net/mlx5: fix legacy non-inline multi-packet performance

[dpdk.git] / drivers / net / mlx5 / mlx5_rxtx.c

/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright 2015 6WIND S.A.
 * Copyright 2015-2019 Mellanox Technologies, Ltd
 */

#include <assert.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>

/* Verbs header. */
/* ISO C doesn't support unnamed structs/unions, disabling -pedantic. */
#ifdef PEDANTIC
#pragma GCC diagnostic ignored "-Wpedantic"
#endif
#include <infiniband/verbs.h>
#include <infiniband/mlx5dv.h>
#ifdef PEDANTIC
#pragma GCC diagnostic error "-Wpedantic"
#endif

#include <rte_mbuf.h>
#include <rte_mempool.h>
#include <rte_prefetch.h>
#include <rte_common.h>
#include <rte_branch_prediction.h>
#include <rte_ether.h>
#include <rte_cycles.h>
#include <rte_flow.h>

#include "mlx5.h"
#include "mlx5_utils.h"
#include "mlx5_rxtx.h"
#include "mlx5_autoconf.h"
#include "mlx5_defs.h"
#include "mlx5_prm.h"

/* TX burst subroutines return codes. */
enum mlx5_txcmp_code {
        MLX5_TXCMP_CODE_EXIT = 0,
        MLX5_TXCMP_CODE_ERROR,
        MLX5_TXCMP_CODE_SINGLE,
        MLX5_TXCMP_CODE_MULTI,
        MLX5_TXCMP_CODE_TSO,
        MLX5_TXCMP_CODE_EMPW,
};

/*
 * These defines are used to configure Tx burst routine option set
 * supported at compile time. The not specified options are optimized out
 * out due to if conditions can be explicitly calculated at compile time.
 * The offloads with bigger runtime check (require more CPU cycles to
 * skip) overhead should have the bigger index - this is needed to
 * select the better matching routine function if no exact match and
 * some offloads are not actually requested.
 */
#define MLX5_TXOFF_CONFIG_MULTI (1u << 0) /* Multi-segment packets.*/
#define MLX5_TXOFF_CONFIG_TSO (1u << 1) /* TCP send offload supported.*/
#define MLX5_TXOFF_CONFIG_SWP (1u << 2) /* Tunnels/SW Parser offloads.*/
#define MLX5_TXOFF_CONFIG_CSUM (1u << 3) /* Check Sums offloaded. */
#define MLX5_TXOFF_CONFIG_INLINE (1u << 4) /* Data inlining supported. */
#define MLX5_TXOFF_CONFIG_VLAN (1u << 5) /* VLAN insertion supported.*/
#define MLX5_TXOFF_CONFIG_METADATA (1u << 6) /* Flow metadata. */
#define MLX5_TXOFF_CONFIG_EMPW (1u << 8) /* Enhanced MPW supported.*/
#define MLX5_TXOFF_CONFIG_MPW (1u << 9) /* Legacy MPW supported.*/

/* The most common offloads groups. */
#define MLX5_TXOFF_CONFIG_NONE 0
#define MLX5_TXOFF_CONFIG_FULL (MLX5_TXOFF_CONFIG_MULTI | \
                                MLX5_TXOFF_CONFIG_TSO | \
                                MLX5_TXOFF_CONFIG_SWP | \
                                MLX5_TXOFF_CONFIG_CSUM | \
                                MLX5_TXOFF_CONFIG_INLINE | \
                                MLX5_TXOFF_CONFIG_VLAN | \
                                MLX5_TXOFF_CONFIG_METADATA)

#define MLX5_TXOFF_CONFIG(mask) (olx & MLX5_TXOFF_CONFIG_##mask)

#define MLX5_TXOFF_DECL(func, olx) \
static uint16_t mlx5_tx_burst_##func(void *txq, \
                                     struct rte_mbuf **pkts, \
                                    uint16_t pkts_n) \
{ \
        return mlx5_tx_burst_tmpl((struct mlx5_txq_data *)txq, \
                    pkts, pkts_n, (olx)); \
}

#define MLX5_TXOFF_INFO(func, olx) {mlx5_tx_burst_##func, olx},

static __rte_always_inline uint32_t
rxq_cq_to_pkt_type(struct mlx5_rxq_data *rxq, volatile struct mlx5_cqe *cqe);

static __rte_always_inline int
mlx5_rx_poll_len(struct mlx5_rxq_data *rxq, volatile struct mlx5_cqe *cqe,
                 uint16_t cqe_cnt, volatile struct mlx5_mini_cqe8 **mcqe);

static __rte_always_inline uint32_t
rxq_cq_to_ol_flags(volatile struct mlx5_cqe *cqe);

static __rte_always_inline void
rxq_cq_to_mbuf(struct mlx5_rxq_data *rxq, struct rte_mbuf *pkt,
               volatile struct mlx5_cqe *cqe, uint32_t rss_hash_res);

static __rte_always_inline void
mprq_buf_replace(struct mlx5_rxq_data *rxq, uint16_t rq_idx,
                 const unsigned int strd_n);

static int
mlx5_queue_state_modify(struct rte_eth_dev *dev,
                        struct mlx5_mp_arg_queue_state_modify *sm);

static inline void
mlx5_lro_update_tcp_hdr(struct rte_tcp_hdr *restrict tcp,
                        volatile struct mlx5_cqe *restrict cqe,
                        uint32_t phcsum);

static inline void
mlx5_lro_update_hdr(uint8_t *restrict padd,
                    volatile struct mlx5_cqe *restrict cqe,
                    uint32_t len);

uint32_t mlx5_ptype_table[] __rte_cache_aligned = {
        [0xff] = RTE_PTYPE_ALL_MASK, /* Last entry for errored packet. */
};

uint8_t mlx5_cksum_table[1 << 10] __rte_cache_aligned;
uint8_t mlx5_swp_types_table[1 << 10] __rte_cache_aligned;

/**
 * Build a table to translate Rx completion flags to packet type.
 *
 * @note: fix mlx5_dev_supported_ptypes_get() if any change here.
 */
void
mlx5_set_ptype_table(void)
{
        unsigned int i;
        uint32_t (*p)[RTE_DIM(mlx5_ptype_table)] = &mlx5_ptype_table;

        /* Last entry must not be overwritten, reserved for errored packet. */
        for (i = 0; i < RTE_DIM(mlx5_ptype_table) - 1; ++i)
                (*p)[i] = RTE_PTYPE_UNKNOWN;
        /*
         * The index to the array should have:
         * bit[1:0] = l3_hdr_type
         * bit[4:2] = l4_hdr_type
         * bit[5] = ip_frag
         * bit[6] = tunneled
         * bit[7] = outer_l3_type
         */
        /* L2 */
        (*p)[0x00] = RTE_PTYPE_L2_ETHER;
        /* L3 */
        (*p)[0x01] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_L4_NONFRAG;
        (*p)[0x02] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_L4_NONFRAG;
        /* Fragmented */
        (*p)[0x21] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_L4_FRAG;
        (*p)[0x22] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_L4_FRAG;
        /* TCP */
        (*p)[0x05] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_L4_TCP;
        (*p)[0x06] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_L4_TCP;
        (*p)[0x0d] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_L4_TCP;
        (*p)[0x0e] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_L4_TCP;
        (*p)[0x11] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_L4_TCP;
        (*p)[0x12] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_L4_TCP;
        /* UDP */
        (*p)[0x09] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_L4_UDP;
        (*p)[0x0a] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_L4_UDP;
        /* Repeat with outer_l3_type being set. Just in case. */
        (*p)[0x81] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_L4_NONFRAG;
        (*p)[0x82] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_L4_NONFRAG;
        (*p)[0xa1] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_L4_FRAG;
        (*p)[0xa2] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_L4_FRAG;
        (*p)[0x85] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_L4_TCP;
        (*p)[0x86] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_L4_TCP;
        (*p)[0x8d] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_L4_TCP;
        (*p)[0x8e] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_L4_TCP;
        (*p)[0x91] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_L4_TCP;
        (*p)[0x92] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_L4_TCP;
        (*p)[0x89] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_L4_UDP;
        (*p)[0x8a] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_L4_UDP;
        /* Tunneled - L3 */
        (*p)[0x40] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN;
        (*p)[0x41] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_NONFRAG;
        (*p)[0x42] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_NONFRAG;
        (*p)[0xc0] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN;
        (*p)[0xc1] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_NONFRAG;
        (*p)[0xc2] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_NONFRAG;
        /* Tunneled - Fragmented */
        (*p)[0x61] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_FRAG;
        (*p)[0x62] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_FRAG;
        (*p)[0xe1] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_FRAG;
        (*p)[0xe2] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_FRAG;
        /* Tunneled - TCP */
        (*p)[0x45] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_TCP;
        (*p)[0x46] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_TCP;
        (*p)[0x4d] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_TCP;
        (*p)[0x4e] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_TCP;
        (*p)[0x51] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_TCP;
        (*p)[0x52] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_TCP;
        (*p)[0xc5] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_TCP;
        (*p)[0xc6] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_TCP;
        (*p)[0xcd] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_TCP;
        (*p)[0xce] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_TCP;
        (*p)[0xd1] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_TCP;
        (*p)[0xd2] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_TCP;
        /* Tunneled - UDP */
        (*p)[0x49] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_UDP;
        (*p)[0x4a] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_UDP;
        (*p)[0xc9] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_UDP;
        (*p)[0xca] = RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV6_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L3_IPV4_EXT_UNKNOWN |
                     RTE_PTYPE_INNER_L4_UDP;
}

/**
 * Build a table to translate packet to checksum type of Verbs.
 */
void
mlx5_set_cksum_table(void)
{
        unsigned int i;
        uint8_t v;

        /*
         * The index should have:
         * bit[0] = PKT_TX_TCP_SEG
         * bit[2:3] = PKT_TX_UDP_CKSUM, PKT_TX_TCP_CKSUM
         * bit[4] = PKT_TX_IP_CKSUM
         * bit[8] = PKT_TX_OUTER_IP_CKSUM
         * bit[9] = tunnel
         */
        for (i = 0; i < RTE_DIM(mlx5_cksum_table); ++i) {
                v = 0;
                if (i & (1 << 9)) {
                        /* Tunneled packet. */
                        if (i & (1 << 8)) /* Outer IP. */
                                v |= MLX5_ETH_WQE_L3_CSUM;
                        if (i & (1 << 4)) /* Inner IP. */
                                v |= MLX5_ETH_WQE_L3_INNER_CSUM;
                        if (i & (3 << 2 | 1 << 0)) /* L4 or TSO. */
                                v |= MLX5_ETH_WQE_L4_INNER_CSUM;
                } else {
                        /* No tunnel. */
                        if (i & (1 << 4)) /* IP. */
                                v |= MLX5_ETH_WQE_L3_CSUM;
                        if (i & (3 << 2 | 1 << 0)) /* L4 or TSO. */
                                v |= MLX5_ETH_WQE_L4_CSUM;
                }
                mlx5_cksum_table[i] = v;
        }
}

/**
 * Build a table to translate packet type of mbuf to SWP type of Verbs.
 */
void
mlx5_set_swp_types_table(void)
{
        unsigned int i;
        uint8_t v;

        /*
         * The index should have:
         * bit[0:1] = PKT_TX_L4_MASK
         * bit[4] = PKT_TX_IPV6
         * bit[8] = PKT_TX_OUTER_IPV6
         * bit[9] = PKT_TX_OUTER_UDP
         */
        for (i = 0; i < RTE_DIM(mlx5_swp_types_table); ++i) {
                v = 0;
                if (i & (1 << 8))
                        v |= MLX5_ETH_WQE_L3_OUTER_IPV6;
                if (i & (1 << 9))
                        v |= MLX5_ETH_WQE_L4_OUTER_UDP;
                if (i & (1 << 4))
                        v |= MLX5_ETH_WQE_L3_INNER_IPV6;
                if ((i & 3) == (PKT_TX_UDP_CKSUM >> 52))
                        v |= MLX5_ETH_WQE_L4_INNER_UDP;
                mlx5_swp_types_table[i] = v;
        }
}

/**
 * Set Software Parser flags and offsets in Ethernet Segment of WQE.
 * Flags must be preliminary initialized to zero.
 *
 * @param loc
 *   Pointer to burst routine local context.
 * @param swp_flags
 *   Pointer to store Software Parser flags
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 *
 * @return
 *   Software Parser offsets packed in dword.
 *   Software Parser flags are set by pointer.
 */
static __rte_always_inline uint32_t
txq_mbuf_to_swp(struct mlx5_txq_local *restrict loc,
                uint8_t *swp_flags,
                unsigned int olx)
{
        uint64_t ol, tunnel;
        unsigned int idx, off;
        uint32_t set;

        if (!MLX5_TXOFF_CONFIG(SWP))
                return 0;
        ol = loc->mbuf->ol_flags;
        tunnel = ol & PKT_TX_TUNNEL_MASK;
        /*
         * Check whether Software Parser is required.
         * Only customized tunnels may ask for.
         */
        if (likely(tunnel != PKT_TX_TUNNEL_UDP && tunnel != PKT_TX_TUNNEL_IP))
                return 0;
        /*
         * The index should have:
         * bit[0:1] = PKT_TX_L4_MASK
         * bit[4] = PKT_TX_IPV6
         * bit[8] = PKT_TX_OUTER_IPV6
         * bit[9] = PKT_TX_OUTER_UDP
         */
        idx = (ol & (PKT_TX_L4_MASK | PKT_TX_IPV6 | PKT_TX_OUTER_IPV6)) >> 52;
        idx |= (tunnel == PKT_TX_TUNNEL_UDP) ? (1 << 9) : 0;
        *swp_flags = mlx5_swp_types_table[idx];
        /*
         * Set offsets for SW parser. Since ConnectX-5, SW parser just
         * complements HW parser. SW parser starts to engage only if HW parser
         * can't reach a header. For the older devices, HW parser will not kick
         * in if any of SWP offsets is set. Therefore, all of the L3 offsets
         * should be set regardless of HW offload.
         */
        off = loc->mbuf->outer_l2_len;
        if (MLX5_TXOFF_CONFIG(VLAN) && ol & PKT_TX_VLAN_PKT)
                off += sizeof(struct rte_vlan_hdr);
        set = (off >> 1) << 8; /* Outer L3 offset. */
        off += loc->mbuf->outer_l3_len;
        if (tunnel == PKT_TX_TUNNEL_UDP)
                set |= off >> 1; /* Outer L4 offset. */
        if (ol & (PKT_TX_IPV4 | PKT_TX_IPV6)) { /* Inner IP. */
                const uint64_t csum = ol & PKT_TX_L4_MASK;
                        off += loc->mbuf->l2_len;
                set |= (off >> 1) << 24; /* Inner L3 offset. */
                if (csum == PKT_TX_TCP_CKSUM ||
                    csum == PKT_TX_UDP_CKSUM ||
                    (MLX5_TXOFF_CONFIG(TSO) && ol & PKT_TX_TCP_SEG)) {
                        off += loc->mbuf->l3_len;
                        set |= (off >> 1) << 16; /* Inner L4 offset. */
                }
        }
        set = rte_cpu_to_le_32(set);
        return set;
}

/**
 * Convert the Checksum offloads to Verbs.
 *
 * @param buf
 *   Pointer to the mbuf.
 *
 * @return
 *   Converted checksum flags.
 */
static __rte_always_inline uint8_t
txq_ol_cksum_to_cs(struct rte_mbuf *buf)
{
        uint32_t idx;
        uint8_t is_tunnel = !!(buf->ol_flags & PKT_TX_TUNNEL_MASK);
        const uint64_t ol_flags_mask = PKT_TX_TCP_SEG | PKT_TX_L4_MASK |
                                       PKT_TX_IP_CKSUM | PKT_TX_OUTER_IP_CKSUM;

        /*
         * The index should have:
         * bit[0] = PKT_TX_TCP_SEG
         * bit[2:3] = PKT_TX_UDP_CKSUM, PKT_TX_TCP_CKSUM
         * bit[4] = PKT_TX_IP_CKSUM
         * bit[8] = PKT_TX_OUTER_IP_CKSUM
         * bit[9] = tunnel
         */
        idx = ((buf->ol_flags & ol_flags_mask) >> 50) | (!!is_tunnel << 9);
        return mlx5_cksum_table[idx];
}

/**
 * Internal function to compute the number of used descriptors in an RX queue
 *
 * @param rxq
 *   The Rx queue.
 *
 * @return
 *   The number of used rx descriptor.
 */
static uint32_t
rx_queue_count(struct mlx5_rxq_data *rxq)
{
        struct rxq_zip *zip = &rxq->zip;
        volatile struct mlx5_cqe *cqe;
        const unsigned int cqe_n = (1 << rxq->cqe_n);
        const unsigned int cqe_cnt = cqe_n - 1;
        unsigned int cq_ci;
        unsigned int used;

        /* if we are processing a compressed cqe */
        if (zip->ai) {
                used = zip->cqe_cnt - zip->ca;
                cq_ci = zip->cq_ci;
        } else {
                used = 0;
                cq_ci = rxq->cq_ci;
        }
        cqe = &(*rxq->cqes)[cq_ci & cqe_cnt];
        while (check_cqe(cqe, cqe_n, cq_ci) != MLX5_CQE_STATUS_HW_OWN) {
                int8_t op_own;
                unsigned int n;

                op_own = cqe->op_own;
                if (MLX5_CQE_FORMAT(op_own) == MLX5_COMPRESSED)
                        n = rte_be_to_cpu_32(cqe->byte_cnt);
                else
                        n = 1;
                cq_ci += n;
                used += n;
                cqe = &(*rxq->cqes)[cq_ci & cqe_cnt];
        }
        used = RTE_MIN(used, (1U << rxq->elts_n) - 1);
        return used;
}

/**
 * DPDK callback to check the status of a rx descriptor.
 *
 * @param rx_queue
 *   The Rx queue.
 * @param[in] offset
 *   The index of the descriptor in the ring.
 *
 * @return
 *   The status of the tx descriptor.
 */
int
mlx5_rx_descriptor_status(void *rx_queue, uint16_t offset)
{
        struct mlx5_rxq_data *rxq = rx_queue;
        struct mlx5_rxq_ctrl *rxq_ctrl =
                        container_of(rxq, struct mlx5_rxq_ctrl, rxq);
        struct rte_eth_dev *dev = ETH_DEV(rxq_ctrl->priv);

        if (dev->rx_pkt_burst != mlx5_rx_burst) {
                rte_errno = ENOTSUP;
                return -rte_errno;
        }
        if (offset >= (1 << rxq->elts_n)) {
                rte_errno = EINVAL;
                return -rte_errno;
        }
        if (offset < rx_queue_count(rxq))
                return RTE_ETH_RX_DESC_DONE;
        return RTE_ETH_RX_DESC_AVAIL;
}

/**
 * DPDK callback to get the number of used descriptors in a RX queue
 *
 * @param dev
 *   Pointer to the device structure.
 *
 * @param rx_queue_id
 *   The Rx queue.
 *
 * @return
 *   The number of used rx descriptor.
 *   -EINVAL if the queue is invalid
 */
uint32_t
mlx5_rx_queue_count(struct rte_eth_dev *dev, uint16_t rx_queue_id)
{
        struct mlx5_priv *priv = dev->data->dev_private;
        struct mlx5_rxq_data *rxq;

        if (dev->rx_pkt_burst != mlx5_rx_burst) {
                rte_errno = ENOTSUP;
                return -rte_errno;
        }
        rxq = (*priv->rxqs)[rx_queue_id];
        if (!rxq) {
                rte_errno = EINVAL;
                return -rte_errno;
        }
        return rx_queue_count(rxq);
}

#define MLX5_SYSTEM_LOG_DIR "/var/log"
/**
 * Dump debug information to log file.
 *
 * @param fname
 *   The file name.
 * @param hex_title
 *   If not NULL this string is printed as a header to the output
 *   and the output will be in hexadecimal view.
 * @param buf
 *   This is the buffer address to print out.
 * @param len
 *   The number of bytes to dump out.
 */
void
mlx5_dump_debug_information(const char *fname, const char *hex_title,
                            const void *buf, unsigned int hex_len)
{
        FILE *fd;

        MKSTR(path, "%s/%s", MLX5_SYSTEM_LOG_DIR, fname);
        fd = fopen(path, "a+");
        if (!fd) {
                DRV_LOG(WARNING, "cannot open %s for debug dump", path);
                MKSTR(path2, "./%s", fname);
                fd = fopen(path2, "a+");
                if (!fd) {
                        DRV_LOG(ERR, "cannot open %s for debug dump", path2);
                        return;
                }
                DRV_LOG(INFO, "New debug dump in file %s", path2);
        } else {
                DRV_LOG(INFO, "New debug dump in file %s", path);
        }
        if (hex_title)
                rte_hexdump(fd, hex_title, buf, hex_len);
        else
                fprintf(fd, "%s", (const char *)buf);
        fprintf(fd, "\n\n\n");
        fclose(fd);
}

/**
 * Move QP from error state to running state and initialize indexes.
 *
 * @param txq_ctrl
 *   Pointer to TX queue control structure.
 *
 * @return
 *   0 on success, else -1.
 */
static int
tx_recover_qp(struct mlx5_txq_ctrl *txq_ctrl)
{
        struct mlx5_mp_arg_queue_state_modify sm = {
                        .is_wq = 0,
                        .queue_id = txq_ctrl->txq.idx,
        };

        if (mlx5_queue_state_modify(ETH_DEV(txq_ctrl->priv), &sm))
                return -1;
        txq_ctrl->txq.wqe_ci = 0;
        txq_ctrl->txq.wqe_pi = 0;
        txq_ctrl->txq.elts_comp = 0;
        return 0;
}

/* Return 1 if the error CQE is signed otherwise, sign it and return 0. */
static int
check_err_cqe_seen(volatile struct mlx5_err_cqe *err_cqe)
{
        static const uint8_t magic[] = "seen";
        int ret = 1;
        unsigned int i;

        for (i = 0; i < sizeof(magic); ++i)
                if (!ret || err_cqe->rsvd1[i] != magic[i]) {
                        ret = 0;
                        err_cqe->rsvd1[i] = magic[i];
                }
        return ret;
}

/**
 * Handle error CQE.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param error_cqe
 *   Pointer to the error CQE.
 *
 * @return
 *   Negative value if queue recovery failed,
 *   the last Tx buffer element to free otherwise.
 */
int
mlx5_tx_error_cqe_handle(struct mlx5_txq_data *restrict txq,
                         volatile struct mlx5_err_cqe *err_cqe)
{
        if (err_cqe->syndrome != MLX5_CQE_SYNDROME_WR_FLUSH_ERR) {
                const uint16_t wqe_m = ((1 << txq->wqe_n) - 1);
                struct mlx5_txq_ctrl *txq_ctrl =
                                container_of(txq, struct mlx5_txq_ctrl, txq);
                uint16_t new_wqe_pi = rte_be_to_cpu_16(err_cqe->wqe_counter);
                int seen = check_err_cqe_seen(err_cqe);

                if (!seen && txq_ctrl->dump_file_n <
                    txq_ctrl->priv->config.max_dump_files_num) {
                        MKSTR(err_str, "Unexpected CQE error syndrome "
                              "0x%02x CQN = %u SQN = %u wqe_counter = %u "
                              "wq_ci = %u cq_ci = %u", err_cqe->syndrome,
                              txq->cqe_s, txq->qp_num_8s >> 8,
                              rte_be_to_cpu_16(err_cqe->wqe_counter),
                              txq->wqe_ci, txq->cq_ci);
                        MKSTR(name, "dpdk_mlx5_port_%u_txq_%u_index_%u_%u",
                              PORT_ID(txq_ctrl->priv), txq->idx,
                              txq_ctrl->dump_file_n, (uint32_t)rte_rdtsc());
                        mlx5_dump_debug_information(name, NULL, err_str, 0);
                        mlx5_dump_debug_information(name, "MLX5 Error CQ:",
                                                    (const void *)((uintptr_t)
                                                    txq->cqes),
                                                    sizeof(*err_cqe) *
                                                    (1 << txq->cqe_n));
                        mlx5_dump_debug_information(name, "MLX5 Error SQ:",
                                                    (const void *)((uintptr_t)
                                                    txq->wqes),
                                                    MLX5_WQE_SIZE *
                                                    (1 << txq->wqe_n));
                        txq_ctrl->dump_file_n++;
                }
                if (!seen)
                        /*
                         * Count errors in WQEs units.
                         * Later it can be improved to count error packets,
                         * for example, by SQ parsing to find how much packets
                         * should be counted for each WQE.
                         */
                        txq->stats.oerrors += ((txq->wqe_ci & wqe_m) -
                                                new_wqe_pi) & wqe_m;
                if (tx_recover_qp(txq_ctrl) == 0) {
                        txq->cq_ci++;
                        /* Release all the remaining buffers. */
                        return txq->elts_head;
                }
                /* Recovering failed - try again later on the same WQE. */
                return -1;
        } else {
                txq->cq_ci++;
        }
        /* Do not release buffers. */
        return txq->elts_tail;
}

/**
 * Translate RX completion flags to packet type.
 *
 * @param[in] rxq
 *   Pointer to RX queue structure.
 * @param[in] cqe
 *   Pointer to CQE.
 *
 * @note: fix mlx5_dev_supported_ptypes_get() if any change here.
 *
 * @return
 *   Packet type for struct rte_mbuf.
 */
static inline uint32_t
rxq_cq_to_pkt_type(struct mlx5_rxq_data *rxq, volatile struct mlx5_cqe *cqe)
{
        uint8_t idx;
        uint8_t pinfo = cqe->pkt_info;
        uint16_t ptype = cqe->hdr_type_etc;

        /*
         * The index to the array should have:
         * bit[1:0] = l3_hdr_type
         * bit[4:2] = l4_hdr_type
         * bit[5] = ip_frag
         * bit[6] = tunneled
         * bit[7] = outer_l3_type
         */
        idx = ((pinfo & 0x3) << 6) | ((ptype & 0xfc00) >> 10);
        return mlx5_ptype_table[idx] | rxq->tunnel * !!(idx & (1 << 6));
}

/**
 * Initialize Rx WQ and indexes.
 *
 * @param[in] rxq
 *   Pointer to RX queue structure.
 */
void
mlx5_rxq_initialize(struct mlx5_rxq_data *rxq)
{
        const unsigned int wqe_n = 1 << rxq->elts_n;
        unsigned int i;

        for (i = 0; (i != wqe_n); ++i) {
                volatile struct mlx5_wqe_data_seg *scat;
                uintptr_t addr;
                uint32_t byte_count;

                if (mlx5_rxq_mprq_enabled(rxq)) {
                        struct mlx5_mprq_buf *buf = (*rxq->mprq_bufs)[i];

                        scat = &((volatile struct mlx5_wqe_mprq *)
                                rxq->wqes)[i].dseg;
                        addr = (uintptr_t)mlx5_mprq_buf_addr(buf,
                                                         1 << rxq->strd_num_n);
                        byte_count = (1 << rxq->strd_sz_n) *
                                        (1 << rxq->strd_num_n);
                } else {
                        struct rte_mbuf *buf = (*rxq->elts)[i];

                        scat = &((volatile struct mlx5_wqe_data_seg *)
                                        rxq->wqes)[i];
                        addr = rte_pktmbuf_mtod(buf, uintptr_t);
                        byte_count = DATA_LEN(buf);
                }
                /* scat->addr must be able to store a pointer. */
                assert(sizeof(scat->addr) >= sizeof(uintptr_t));
                *scat = (struct mlx5_wqe_data_seg){
                        .addr = rte_cpu_to_be_64(addr),
                        .byte_count = rte_cpu_to_be_32(byte_count),
                        .lkey = mlx5_rx_addr2mr(rxq, addr),
                };
        }
        rxq->consumed_strd = 0;
        rxq->decompressed = 0;
        rxq->rq_pi = 0;
        rxq->zip = (struct rxq_zip){
                .ai = 0,
        };
        /* Update doorbell counter. */
        rxq->rq_ci = wqe_n >> rxq->sges_n;
        rte_cio_wmb();
        *rxq->rq_db = rte_cpu_to_be_32(rxq->rq_ci);
}

/**
 * Modify a Verbs/DevX queue state.
 * This must be called from the primary process.
 *
 * @param dev
 *   Pointer to Ethernet device.
 * @param sm
 *   State modify request parameters.
 *
 * @return
 *   0 in case of success else non-zero value and rte_errno is set.
 */
int
mlx5_queue_state_modify_primary(struct rte_eth_dev *dev,
                        const struct mlx5_mp_arg_queue_state_modify *sm)
{
        int ret;
        struct mlx5_priv *priv = dev->data->dev_private;

        if (sm->is_wq) {
                struct mlx5_rxq_data *rxq = (*priv->rxqs)[sm->queue_id];
                struct mlx5_rxq_ctrl *rxq_ctrl =
                        container_of(rxq, struct mlx5_rxq_ctrl, rxq);

                if (rxq_ctrl->obj->type == MLX5_RXQ_OBJ_TYPE_IBV) {
                        struct ibv_wq_attr mod = {
                                .attr_mask = IBV_WQ_ATTR_STATE,
                                .wq_state = sm->state,
                        };

                        ret = mlx5_glue->modify_wq(rxq_ctrl->obj->wq, &mod);
                } else { /* rxq_ctrl->obj->type == MLX5_RXQ_OBJ_TYPE_DEVX_RQ. */
                        struct mlx5_devx_modify_rq_attr rq_attr;

                        memset(&rq_attr, 0, sizeof(rq_attr));
                        if (sm->state == IBV_WQS_RESET) {
                                rq_attr.rq_state = MLX5_RQC_STATE_ERR;
                                rq_attr.state = MLX5_RQC_STATE_RST;
                        } else if (sm->state == IBV_WQS_RDY) {
                                rq_attr.rq_state = MLX5_RQC_STATE_RST;
                                rq_attr.state = MLX5_RQC_STATE_RDY;
                        } else if (sm->state == IBV_WQS_ERR) {
                                rq_attr.rq_state = MLX5_RQC_STATE_RDY;
                                rq_attr.state = MLX5_RQC_STATE_ERR;
                        }
                        ret = mlx5_devx_cmd_modify_rq(rxq_ctrl->obj->rq,
                                                      &rq_attr);
                }
                if (ret) {
                        DRV_LOG(ERR, "Cannot change Rx WQ state to %u  - %s",
                                        sm->state, strerror(errno));
                        rte_errno = errno;
                        return ret;
                }
        } else {
                struct mlx5_txq_data *txq = (*priv->txqs)[sm->queue_id];
                struct mlx5_txq_ctrl *txq_ctrl =
                        container_of(txq, struct mlx5_txq_ctrl, txq);
                struct ibv_qp_attr mod = {
                        .qp_state = IBV_QPS_RESET,
                        .port_num = (uint8_t)priv->ibv_port,
                };
                struct ibv_qp *qp = txq_ctrl->obj->qp;

                ret = mlx5_glue->modify_qp(qp, &mod, IBV_QP_STATE);
                if (ret) {
                        DRV_LOG(ERR, "Cannot change the Tx QP state to RESET "
                                "%s", strerror(errno));
                        rte_errno = errno;
                        return ret;
                }
                mod.qp_state = IBV_QPS_INIT;
                ret = mlx5_glue->modify_qp(qp, &mod,
                                           (IBV_QP_STATE | IBV_QP_PORT));
                if (ret) {
                        DRV_LOG(ERR, "Cannot change Tx QP state to INIT %s",
                                strerror(errno));
                        rte_errno = errno;
                        return ret;
                }
                mod.qp_state = IBV_QPS_RTR;
                ret = mlx5_glue->modify_qp(qp, &mod, IBV_QP_STATE);
                if (ret) {
                        DRV_LOG(ERR, "Cannot change Tx QP state to RTR %s",
                                strerror(errno));
                        rte_errno = errno;
                        return ret;
                }
                mod.qp_state = IBV_QPS_RTS;
                ret = mlx5_glue->modify_qp(qp, &mod, IBV_QP_STATE);
                if (ret) {
                        DRV_LOG(ERR, "Cannot change Tx QP state to RTS %s",
                                strerror(errno));
                        rte_errno = errno;
                        return ret;
                }
        }
        return 0;
}

/**
 * Modify a Verbs queue state.
 *
 * @param dev
 *   Pointer to Ethernet device.
 * @param sm
 *   State modify request parameters.
 *
 * @return
 *   0 in case of success else non-zero value.
 */
static int
mlx5_queue_state_modify(struct rte_eth_dev *dev,
                        struct mlx5_mp_arg_queue_state_modify *sm)
{
        int ret = 0;

        switch (rte_eal_process_type()) {
        case RTE_PROC_PRIMARY:
                ret = mlx5_queue_state_modify_primary(dev, sm);
                break;
        case RTE_PROC_SECONDARY:
                ret = mlx5_mp_req_queue_state_modify(dev, sm);
                break;
        default:
                break;
        }
        return ret;
}

/**
 * Handle a Rx error.
 * The function inserts the RQ state to reset when the first error CQE is
 * shown, then drains the CQ by the caller function loop. When the CQ is empty,
 * it moves the RQ state to ready and initializes the RQ.
 * Next CQE identification and error counting are in the caller responsibility.
 *
 * @param[in] rxq
 *   Pointer to RX queue structure.
 * @param[in] vec
 *   1 when called from vectorized Rx burst, need to prepare mbufs for the RQ.
 *   0 when called from non-vectorized Rx burst.
 *
 * @return
 *   -1 in case of recovery error, otherwise the CQE status.
 */
int
mlx5_rx_err_handle(struct mlx5_rxq_data *rxq, uint8_t vec)
{
        const uint16_t cqe_n = 1 << rxq->cqe_n;
        const uint16_t cqe_mask = cqe_n - 1;
        const unsigned int wqe_n = 1 << rxq->elts_n;
        struct mlx5_rxq_ctrl *rxq_ctrl =
                        container_of(rxq, struct mlx5_rxq_ctrl, rxq);
        union {
                volatile struct mlx5_cqe *cqe;
                volatile struct mlx5_err_cqe *err_cqe;
        } u = {
                .cqe = &(*rxq->cqes)[rxq->cq_ci & cqe_mask],
        };
        struct mlx5_mp_arg_queue_state_modify sm;
        int ret;

        switch (rxq->err_state) {
        case MLX5_RXQ_ERR_STATE_NO_ERROR:
                rxq->err_state = MLX5_RXQ_ERR_STATE_NEED_RESET;
                /* Fall-through */
        case MLX5_RXQ_ERR_STATE_NEED_RESET:
                sm.is_wq = 1;
                sm.queue_id = rxq->idx;
                sm.state = IBV_WQS_RESET;
                if (mlx5_queue_state_modify(ETH_DEV(rxq_ctrl->priv), &sm))
                        return -1;
                if (rxq_ctrl->dump_file_n <
                    rxq_ctrl->priv->config.max_dump_files_num) {
                        MKSTR(err_str, "Unexpected CQE error syndrome "
                              "0x%02x CQN = %u RQN = %u wqe_counter = %u"
                              " rq_ci = %u cq_ci = %u", u.err_cqe->syndrome,
                              rxq->cqn, rxq_ctrl->wqn,
                              rte_be_to_cpu_16(u.err_cqe->wqe_counter),
                              rxq->rq_ci << rxq->sges_n, rxq->cq_ci);
                        MKSTR(name, "dpdk_mlx5_port_%u_rxq_%u_%u",
                              rxq->port_id, rxq->idx, (uint32_t)rte_rdtsc());
                        mlx5_dump_debug_information(name, NULL, err_str, 0);
                        mlx5_dump_debug_information(name, "MLX5 Error CQ:",
                                                    (const void *)((uintptr_t)
                                                                    rxq->cqes),
                                                    sizeof(*u.cqe) * cqe_n);
                        mlx5_dump_debug_information(name, "MLX5 Error RQ:",
                                                    (const void *)((uintptr_t)
                                                                    rxq->wqes),
                                                    16 * wqe_n);
                        rxq_ctrl->dump_file_n++;
                }
                rxq->err_state = MLX5_RXQ_ERR_STATE_NEED_READY;
                /* Fall-through */
        case MLX5_RXQ_ERR_STATE_NEED_READY:
                ret = check_cqe(u.cqe, cqe_n, rxq->cq_ci);
                if (ret == MLX5_CQE_STATUS_HW_OWN) {
                        rte_cio_wmb();
                        *rxq->cq_db = rte_cpu_to_be_32(rxq->cq_ci);
                        rte_cio_wmb();
                        /*
                         * The RQ consumer index must be zeroed while moving
                         * from RESET state to RDY state.
                         */
                        *rxq->rq_db = rte_cpu_to_be_32(0);
                        rte_cio_wmb();
                        sm.is_wq = 1;
                        sm.queue_id = rxq->idx;
                        sm.state = IBV_WQS_RDY;
                        if (mlx5_queue_state_modify(ETH_DEV(rxq_ctrl->priv),
                                                    &sm))
                                return -1;
                        if (vec) {
                                const uint16_t q_mask = wqe_n - 1;
                                uint16_t elt_idx;
                                struct rte_mbuf **elt;
                                int i;
                                unsigned int n = wqe_n - (rxq->rq_ci -
                                                          rxq->rq_pi);

                                for (i = 0; i < (int)n; ++i) {
                                        elt_idx = (rxq->rq_ci + i) & q_mask;
                                        elt = &(*rxq->elts)[elt_idx];
                                        *elt = rte_mbuf_raw_alloc(rxq->mp);
                                        if (!*elt) {
                                                for (i--; i >= 0; --i) {
                                                        elt_idx = (rxq->rq_ci +
                                                                   i) & q_mask;
                                                        elt = &(*rxq->elts)
                                                                [elt_idx];
                                                        rte_pktmbuf_free_seg
                                                                (*elt);
                                                }
                                                return -1;
                                        }
                                }
                                for (i = 0; i < (int)wqe_n; ++i) {
                                        elt = &(*rxq->elts)[i];
                                        DATA_LEN(*elt) =
                                                (uint16_t)((*elt)->buf_len -
                                                rte_pktmbuf_headroom(*elt));
                                }
                                /* Padding with a fake mbuf for vec Rx. */
                                for (i = 0; i < MLX5_VPMD_DESCS_PER_LOOP; ++i)
                                        (*rxq->elts)[wqe_n + i] =
                                                                &rxq->fake_mbuf;
                        }
                        mlx5_rxq_initialize(rxq);
                        rxq->err_state = MLX5_RXQ_ERR_STATE_NO_ERROR;
                }
                return ret;
        default:
                return -1;
        }
}

/**
 * Get size of the next packet for a given CQE. For compressed CQEs, the
 * consumer index is updated only once all packets of the current one have
 * been processed.
 *
 * @param rxq
 *   Pointer to RX queue.
 * @param cqe
 *   CQE to process.
 * @param[out] mcqe
 *   Store pointer to mini-CQE if compressed. Otherwise, the pointer is not
 *   written.
 *
 * @return
 *   0 in case of empty CQE, otherwise the packet size in bytes.
 */
static inline int
mlx5_rx_poll_len(struct mlx5_rxq_data *rxq, volatile struct mlx5_cqe *cqe,
                 uint16_t cqe_cnt, volatile struct mlx5_mini_cqe8 **mcqe)
{
        struct rxq_zip *zip = &rxq->zip;
        uint16_t cqe_n = cqe_cnt + 1;
        int len;
        uint16_t idx, end;

        do {
                len = 0;
                /* Process compressed data in the CQE and mini arrays. */
                if (zip->ai) {
                        volatile struct mlx5_mini_cqe8 (*mc)[8] =
                                (volatile struct mlx5_mini_cqe8 (*)[8])
                                (uintptr_t)(&(*rxq->cqes)[zip->ca &
                                                          cqe_cnt].pkt_info);

                        len = rte_be_to_cpu_32((*mc)[zip->ai & 7].byte_cnt);
                        *mcqe = &(*mc)[zip->ai & 7];
                        if ((++zip->ai & 7) == 0) {
                                /* Invalidate consumed CQEs */
                                idx = zip->ca;
                                end = zip->na;
                                while (idx != end) {
                                        (*rxq->cqes)[idx & cqe_cnt].op_own =
                                                MLX5_CQE_INVALIDATE;
                                        ++idx;
                                }
                                /*
                                 * Increment consumer index to skip the number
                                 * of CQEs consumed. Hardware leaves holes in
                                 * the CQ ring for software use.
                                 */
                                zip->ca = zip->na;
                                zip->na += 8;
                        }
                        if (unlikely(rxq->zip.ai == rxq->zip.cqe_cnt)) {
                                /* Invalidate the rest */
                                idx = zip->ca;
                                end = zip->cq_ci;

                                while (idx != end) {
                                        (*rxq->cqes)[idx & cqe_cnt].op_own =
                                                MLX5_CQE_INVALIDATE;
                                        ++idx;
                                }
                                rxq->cq_ci = zip->cq_ci;
                                zip->ai = 0;
                        }
                /*
                 * No compressed data, get next CQE and verify if it is
                 * compressed.
                 */
                } else {
                        int ret;
                        int8_t op_own;

                        ret = check_cqe(cqe, cqe_n, rxq->cq_ci);
                        if (unlikely(ret != MLX5_CQE_STATUS_SW_OWN)) {
                                if (unlikely(ret == MLX5_CQE_STATUS_ERR ||
                                             rxq->err_state)) {
                                        ret = mlx5_rx_err_handle(rxq, 0);
                                        if (ret == MLX5_CQE_STATUS_HW_OWN ||
                                            ret == -1)
                                                return 0;
                                } else {
                                        return 0;
                                }
                        }
                        ++rxq->cq_ci;
                        op_own = cqe->op_own;
                        if (MLX5_CQE_FORMAT(op_own) == MLX5_COMPRESSED) {
                                volatile struct mlx5_mini_cqe8 (*mc)[8] =
                                        (volatile struct mlx5_mini_cqe8 (*)[8])
                                        (uintptr_t)(&(*rxq->cqes)
                                                [rxq->cq_ci &
                                                 cqe_cnt].pkt_info);

                                /* Fix endianness. */
                                zip->cqe_cnt = rte_be_to_cpu_32(cqe->byte_cnt);
                                /*
                                 * Current mini array position is the one
                                 * returned by check_cqe64().
                                 *
                                 * If completion comprises several mini arrays,
                                 * as a special case the second one is located
                                 * 7 CQEs after the initial CQE instead of 8
                                 * for subsequent ones.
                                 */
                                zip->ca = rxq->cq_ci;
                                zip->na = zip->ca + 7;
                                /* Compute the next non compressed CQE. */
                                --rxq->cq_ci;
                                zip->cq_ci = rxq->cq_ci + zip->cqe_cnt;
                                /* Get packet size to return. */
                                len = rte_be_to_cpu_32((*mc)[0].byte_cnt);
                                *mcqe = &(*mc)[0];
                                zip->ai = 1;
                                /* Prefetch all to be invalidated */
                                idx = zip->ca;
                                end = zip->cq_ci;
                                while (idx != end) {
                                        rte_prefetch0(&(*rxq->cqes)[(idx) &
                                                                    cqe_cnt]);
                                        ++idx;
                                }
                        } else {
                                len = rte_be_to_cpu_32(cqe->byte_cnt);
                        }
                }
                if (unlikely(rxq->err_state)) {
                        cqe = &(*rxq->cqes)[rxq->cq_ci & cqe_cnt];
                        ++rxq->stats.idropped;
                } else {
                        return len;
                }
        } while (1);
}

/**
 * Translate RX completion flags to offload flags.
 *
 * @param[in] cqe
 *   Pointer to CQE.
 *
 * @return
 *   Offload flags (ol_flags) for struct rte_mbuf.
 */
static inline uint32_t
rxq_cq_to_ol_flags(volatile struct mlx5_cqe *cqe)
{
        uint32_t ol_flags = 0;
        uint16_t flags = rte_be_to_cpu_16(cqe->hdr_type_etc);

        ol_flags =
                TRANSPOSE(flags,
                          MLX5_CQE_RX_L3_HDR_VALID,
                          PKT_RX_IP_CKSUM_GOOD) |
                TRANSPOSE(flags,
                          MLX5_CQE_RX_L4_HDR_VALID,
                          PKT_RX_L4_CKSUM_GOOD);
        return ol_flags;
}

/**
 * Fill in mbuf fields from RX completion flags.
 * Note that pkt->ol_flags should be initialized outside of this function.
 *
 * @param rxq
 *   Pointer to RX queue.
 * @param pkt
 *   mbuf to fill.
 * @param cqe
 *   CQE to process.
 * @param rss_hash_res
 *   Packet RSS Hash result.
 */
static inline void
rxq_cq_to_mbuf(struct mlx5_rxq_data *rxq, struct rte_mbuf *pkt,
               volatile struct mlx5_cqe *cqe, uint32_t rss_hash_res)
{
        /* Update packet information. */
        pkt->packet_type = rxq_cq_to_pkt_type(rxq, cqe);
        if (rss_hash_res && rxq->rss_hash) {
                pkt->hash.rss = rss_hash_res;
                pkt->ol_flags |= PKT_RX_RSS_HASH;
        }
        if (rxq->mark && MLX5_FLOW_MARK_IS_VALID(cqe->sop_drop_qpn)) {
                pkt->ol_flags |= PKT_RX_FDIR;
                if (cqe->sop_drop_qpn !=
                    rte_cpu_to_be_32(MLX5_FLOW_MARK_DEFAULT)) {
                        uint32_t mark = cqe->sop_drop_qpn;

                        pkt->ol_flags |= PKT_RX_FDIR_ID;
                        pkt->hash.fdir.hi = mlx5_flow_mark_get(mark);
                }
        }
        if (rte_flow_dynf_metadata_avail() && cqe->flow_table_metadata) {
                pkt->ol_flags |= PKT_RX_DYNF_METADATA;
                *RTE_FLOW_DYNF_METADATA(pkt) = cqe->flow_table_metadata;
        }
        if (rxq->csum)
                pkt->ol_flags |= rxq_cq_to_ol_flags(cqe);
        if (rxq->vlan_strip &&
            (cqe->hdr_type_etc & rte_cpu_to_be_16(MLX5_CQE_VLAN_STRIPPED))) {
                pkt->ol_flags |= PKT_RX_VLAN | PKT_RX_VLAN_STRIPPED;
                pkt->vlan_tci = rte_be_to_cpu_16(cqe->vlan_info);
        }
        if (rxq->hw_timestamp) {
                pkt->timestamp = rte_be_to_cpu_64(cqe->timestamp);
                pkt->ol_flags |= PKT_RX_TIMESTAMP;
        }
}

/**
 * DPDK callback for RX.
 *
 * @param dpdk_rxq
 *   Generic pointer to RX queue structure.
 * @param[out] pkts
 *   Array to store received packets.
 * @param pkts_n
 *   Maximum number of packets in array.
 *
 * @return
 *   Number of packets successfully received (<= pkts_n).
 */
uint16_t
mlx5_rx_burst(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
{
        struct mlx5_rxq_data *rxq = dpdk_rxq;
        const unsigned int wqe_cnt = (1 << rxq->elts_n) - 1;
        const unsigned int cqe_cnt = (1 << rxq->cqe_n) - 1;
        const unsigned int sges_n = rxq->sges_n;
        struct rte_mbuf *pkt = NULL;
        struct rte_mbuf *seg = NULL;
        volatile struct mlx5_cqe *cqe =
                &(*rxq->cqes)[rxq->cq_ci & cqe_cnt];
        unsigned int i = 0;
        unsigned int rq_ci = rxq->rq_ci << sges_n;
        int len = 0; /* keep its value across iterations. */

        while (pkts_n) {
                unsigned int idx = rq_ci & wqe_cnt;
                volatile struct mlx5_wqe_data_seg *wqe =
                        &((volatile struct mlx5_wqe_data_seg *)rxq->wqes)[idx];
                struct rte_mbuf *rep = (*rxq->elts)[idx];
                volatile struct mlx5_mini_cqe8 *mcqe = NULL;
                uint32_t rss_hash_res;

                if (pkt)
                        NEXT(seg) = rep;
                seg = rep;
                rte_prefetch0(seg);
                rte_prefetch0(cqe);
                rte_prefetch0(wqe);
                rep = rte_mbuf_raw_alloc(rxq->mp);
                if (unlikely(rep == NULL)) {
                        ++rxq->stats.rx_nombuf;
                        if (!pkt) {
                                /*
                                 * no buffers before we even started,
                                 * bail out silently.
                                 */
                                break;
                        }
                        while (pkt != seg) {
                                assert(pkt != (*rxq->elts)[idx]);
                                rep = NEXT(pkt);
                                NEXT(pkt) = NULL;
                                NB_SEGS(pkt) = 1;
                                rte_mbuf_raw_free(pkt);
                                pkt = rep;
                        }
                        break;
                }
                if (!pkt) {
                        cqe = &(*rxq->cqes)[rxq->cq_ci & cqe_cnt];
                        len = mlx5_rx_poll_len(rxq, cqe, cqe_cnt, &mcqe);
                        if (!len) {
                                rte_mbuf_raw_free(rep);
                                break;
                        }
                        pkt = seg;
                        assert(len >= (rxq->crc_present << 2));
                        pkt->ol_flags = 0;
                        /* If compressed, take hash result from mini-CQE. */
                        rss_hash_res = rte_be_to_cpu_32(mcqe == NULL ?
                                                        cqe->rx_hash_res :
                                                        mcqe->rx_hash_result);
                        rxq_cq_to_mbuf(rxq, pkt, cqe, rss_hash_res);
                        if (rxq->crc_present)
                                len -= RTE_ETHER_CRC_LEN;
                        PKT_LEN(pkt) = len;
                        if (cqe->lro_num_seg > 1) {
                                mlx5_lro_update_hdr
                                        (rte_pktmbuf_mtod(pkt, uint8_t *), cqe,
                                         len);
                                pkt->ol_flags |= PKT_RX_LRO;
                                pkt->tso_segsz = len / cqe->lro_num_seg;
                        }
                }
                DATA_LEN(rep) = DATA_LEN(seg);
                PKT_LEN(rep) = PKT_LEN(seg);
                SET_DATA_OFF(rep, DATA_OFF(seg));
                PORT(rep) = PORT(seg);
                (*rxq->elts)[idx] = rep;
                /*
                 * Fill NIC descriptor with the new buffer.  The lkey and size
                 * of the buffers are already known, only the buffer address
                 * changes.
                 */
                wqe->addr = rte_cpu_to_be_64(rte_pktmbuf_mtod(rep, uintptr_t));
                /* If there's only one MR, no need to replace LKey in WQE. */
                if (unlikely(mlx5_mr_btree_len(&rxq->mr_ctrl.cache_bh) > 1))
                        wqe->lkey = mlx5_rx_mb2mr(rxq, rep);
                if (len > DATA_LEN(seg)) {
                        len -= DATA_LEN(seg);
                        ++NB_SEGS(pkt);
                        ++rq_ci;
                        continue;
                }
                DATA_LEN(seg) = len;
#ifdef MLX5_PMD_SOFT_COUNTERS
                /* Increment bytes counter. */
                rxq->stats.ibytes += PKT_LEN(pkt);
#endif
                /* Return packet. */
                *(pkts++) = pkt;
                pkt = NULL;
                --pkts_n;
                ++i;
                /* Align consumer index to the next stride. */
                rq_ci >>= sges_n;
                ++rq_ci;
                rq_ci <<= sges_n;
        }
        if (unlikely((i == 0) && ((rq_ci >> sges_n) == rxq->rq_ci)))
                return 0;
        /* Update the consumer index. */
        rxq->rq_ci = rq_ci >> sges_n;
        rte_cio_wmb();
        *rxq->cq_db = rte_cpu_to_be_32(rxq->cq_ci);
        rte_cio_wmb();
        *rxq->rq_db = rte_cpu_to_be_32(rxq->rq_ci);
#ifdef MLX5_PMD_SOFT_COUNTERS
        /* Increment packets counter. */
        rxq->stats.ipackets += i;
#endif
        return i;
}

/**
 * Update LRO packet TCP header.
 * The HW LRO feature doesn't update the TCP header after coalescing the
 * TCP segments but supplies information in CQE to fill it by SW.
 *
 * @param tcp
 *   Pointer to the TCP header.
 * @param cqe
 *   Pointer to the completion entry..
 * @param phcsum
 *   The L3 pseudo-header checksum.
 */
static inline void
mlx5_lro_update_tcp_hdr(struct rte_tcp_hdr *restrict tcp,
                        volatile struct mlx5_cqe *restrict cqe,
                        uint32_t phcsum)
{
        uint8_t l4_type = (rte_be_to_cpu_16(cqe->hdr_type_etc) &
                           MLX5_CQE_L4_TYPE_MASK) >> MLX5_CQE_L4_TYPE_SHIFT;
        /*
         * The HW calculates only the TCP payload checksum, need to complete
         * the TCP header checksum and the L3 pseudo-header checksum.
         */
        uint32_t csum = phcsum + cqe->csum;

        if (l4_type == MLX5_L4_HDR_TYPE_TCP_EMPTY_ACK ||
            l4_type == MLX5_L4_HDR_TYPE_TCP_WITH_ACL) {
                tcp->tcp_flags |= RTE_TCP_ACK_FLAG;
                tcp->recv_ack = cqe->lro_ack_seq_num;
                tcp->rx_win = cqe->lro_tcp_win;
        }
        if (cqe->lro_tcppsh_abort_dupack & MLX5_CQE_LRO_PUSH_MASK)
                tcp->tcp_flags |= RTE_TCP_PSH_FLAG;
        tcp->cksum = 0;
        csum += rte_raw_cksum(tcp, (tcp->data_off & 0xF) * 4);
        csum = ((csum & 0xffff0000) >> 16) + (csum & 0xffff);
        csum = (~csum) & 0xffff;
        if (csum == 0)
                csum = 0xffff;
        tcp->cksum = csum;
}

/**
 * Update LRO packet headers.
 * The HW LRO feature doesn't update the L3/TCP headers after coalescing the
 * TCP segments but supply information in CQE to fill it by SW.
 *
 * @param padd
 *   The packet address.
 * @param cqe
 *   Pointer to the completion entry..
 * @param len
 *   The packet length.
 */
static inline void
mlx5_lro_update_hdr(uint8_t *restrict padd,
                    volatile struct mlx5_cqe *restrict cqe,
                    uint32_t len)
{
        union {
                struct rte_ether_hdr *eth;
                struct rte_vlan_hdr *vlan;
                struct rte_ipv4_hdr *ipv4;
                struct rte_ipv6_hdr *ipv6;
                struct rte_tcp_hdr *tcp;
                uint8_t *hdr;
        } h = {
                        .hdr = padd,
        };
        uint16_t proto = h.eth->ether_type;
        uint32_t phcsum;

        h.eth++;
        while (proto == RTE_BE16(RTE_ETHER_TYPE_VLAN) ||
               proto == RTE_BE16(RTE_ETHER_TYPE_QINQ)) {
                proto = h.vlan->eth_proto;
                h.vlan++;
        }
        if (proto == RTE_BE16(RTE_ETHER_TYPE_IPV4)) {
                h.ipv4->time_to_live = cqe->lro_min_ttl;
                h.ipv4->total_length = rte_cpu_to_be_16(len - (h.hdr - padd));
                h.ipv4->hdr_checksum = 0;
                h.ipv4->hdr_checksum = rte_ipv4_cksum(h.ipv4);
                phcsum = rte_ipv4_phdr_cksum(h.ipv4, 0);
                h.ipv4++;
        } else {
                h.ipv6->hop_limits = cqe->lro_min_ttl;
                h.ipv6->payload_len = rte_cpu_to_be_16(len - (h.hdr - padd) -
                                                       sizeof(*h.ipv6));
                phcsum = rte_ipv6_phdr_cksum(h.ipv6, 0);
                h.ipv6++;
        }
        mlx5_lro_update_tcp_hdr(h.tcp, cqe, phcsum);
}

void
mlx5_mprq_buf_free_cb(void *addr __rte_unused, void *opaque)
{
        struct mlx5_mprq_buf *buf = opaque;

        if (rte_atomic16_read(&buf->refcnt) == 1) {
                rte_mempool_put(buf->mp, buf);
        } else if (rte_atomic16_add_return(&buf->refcnt, -1) == 0) {
                rte_atomic16_set(&buf->refcnt, 1);
                rte_mempool_put(buf->mp, buf);
        }
}

void
mlx5_mprq_buf_free(struct mlx5_mprq_buf *buf)
{
        mlx5_mprq_buf_free_cb(NULL, buf);
}

static inline void
mprq_buf_replace(struct mlx5_rxq_data *rxq, uint16_t rq_idx,
                 const unsigned int strd_n)
{
        struct mlx5_mprq_buf *rep = rxq->mprq_repl;
        volatile struct mlx5_wqe_data_seg *wqe =
                &((volatile struct mlx5_wqe_mprq *)rxq->wqes)[rq_idx].dseg;
        void *addr;

        assert(rep != NULL);
        /* Replace MPRQ buf. */
        (*rxq->mprq_bufs)[rq_idx] = rep;
        /* Replace WQE. */
        addr = mlx5_mprq_buf_addr(rep, strd_n);
        wqe->addr = rte_cpu_to_be_64((uintptr_t)addr);
        /* If there's only one MR, no need to replace LKey in WQE. */
        if (unlikely(mlx5_mr_btree_len(&rxq->mr_ctrl.cache_bh) > 1))
                wqe->lkey = mlx5_rx_addr2mr(rxq, (uintptr_t)addr);
        /* Stash a mbuf for next replacement. */
        if (likely(!rte_mempool_get(rxq->mprq_mp, (void **)&rep)))
                rxq->mprq_repl = rep;
        else
                rxq->mprq_repl = NULL;
}

/**
 * DPDK callback for RX with Multi-Packet RQ support.
 *
 * @param dpdk_rxq
 *   Generic pointer to RX queue structure.
 * @param[out] pkts
 *   Array to store received packets.
 * @param pkts_n
 *   Maximum number of packets in array.
 *
 * @return
 *   Number of packets successfully received (<= pkts_n).
 */
uint16_t
mlx5_rx_burst_mprq(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
{
        struct mlx5_rxq_data *rxq = dpdk_rxq;
        const unsigned int strd_n = 1 << rxq->strd_num_n;
        const unsigned int strd_sz = 1 << rxq->strd_sz_n;
        const unsigned int strd_shift =
                MLX5_MPRQ_STRIDE_SHIFT_BYTE * rxq->strd_shift_en;
        const unsigned int cq_mask = (1 << rxq->cqe_n) - 1;
        const unsigned int wq_mask = (1 << rxq->elts_n) - 1;
        volatile struct mlx5_cqe *cqe = &(*rxq->cqes)[rxq->cq_ci & cq_mask];
        unsigned int i = 0;
        uint32_t rq_ci = rxq->rq_ci;
        uint16_t consumed_strd = rxq->consumed_strd;
        uint16_t headroom_sz = rxq->strd_headroom_en * RTE_PKTMBUF_HEADROOM;
        struct mlx5_mprq_buf *buf = (*rxq->mprq_bufs)[rq_ci & wq_mask];

        while (i < pkts_n) {
                struct rte_mbuf *pkt;
                void *addr;
                int ret;
                unsigned int len;
                uint16_t strd_cnt;
                uint16_t strd_idx;
                uint32_t offset;
                uint32_t byte_cnt;
                volatile struct mlx5_mini_cqe8 *mcqe = NULL;
                uint32_t rss_hash_res = 0;
                uint8_t lro_num_seg;

                if (consumed_strd == strd_n) {
                        /* Replace WQE only if the buffer is still in use. */
                        if (rte_atomic16_read(&buf->refcnt) > 1) {
                                mprq_buf_replace(rxq, rq_ci & wq_mask, strd_n);
                                /* Release the old buffer. */
                                mlx5_mprq_buf_free(buf);
                        } else if (unlikely(rxq->mprq_repl == NULL)) {
                                struct mlx5_mprq_buf *rep;

                                /*
                                 * Currently, the MPRQ mempool is out of buffer
                                 * and doing memcpy regardless of the size of Rx
                                 * packet. Retry allocation to get back to
                                 * normal.
                                 */
                                if (!rte_mempool_get(rxq->mprq_mp,
                                                     (void **)&rep))
                                        rxq->mprq_repl = rep;
                        }
                        /* Advance to the next WQE. */
                        consumed_strd = 0;
                        ++rq_ci;
                        buf = (*rxq->mprq_bufs)[rq_ci & wq_mask];
                }
                cqe = &(*rxq->cqes)[rxq->cq_ci & cq_mask];
                ret = mlx5_rx_poll_len(rxq, cqe, cq_mask, &mcqe);
                if (!ret)
                        break;
                byte_cnt = ret;
                strd_cnt = (byte_cnt & MLX5_MPRQ_STRIDE_NUM_MASK) >>
                           MLX5_MPRQ_STRIDE_NUM_SHIFT;
                assert(strd_cnt);
                consumed_strd += strd_cnt;
                if (byte_cnt & MLX5_MPRQ_FILLER_MASK)
                        continue;
                if (mcqe == NULL) {
                        rss_hash_res = rte_be_to_cpu_32(cqe->rx_hash_res);
                        strd_idx = rte_be_to_cpu_16(cqe->wqe_counter);
                } else {
                        /* mini-CQE for MPRQ doesn't have hash result. */
                        strd_idx = rte_be_to_cpu_16(mcqe->stride_idx);
                }
                assert(strd_idx < strd_n);
                assert(!((rte_be_to_cpu_16(cqe->wqe_id) ^ rq_ci) & wq_mask));
                lro_num_seg = cqe->lro_num_seg;
                /*
                 * Currently configured to receive a packet per a stride. But if
                 * MTU is adjusted through kernel interface, device could
                 * consume multiple strides without raising an error. In this
                 * case, the packet should be dropped because it is bigger than
                 * the max_rx_pkt_len.
                 */
                if (unlikely(!lro_num_seg && strd_cnt > 1)) {
                        ++rxq->stats.idropped;
                        continue;
                }
                pkt = rte_pktmbuf_alloc(rxq->mp);
                if (unlikely(pkt == NULL)) {
                        ++rxq->stats.rx_nombuf;
                        break;
                }
                len = (byte_cnt & MLX5_MPRQ_LEN_MASK) >> MLX5_MPRQ_LEN_SHIFT;
                assert((int)len >= (rxq->crc_present << 2));
                if (rxq->crc_present)
                        len -= RTE_ETHER_CRC_LEN;
                offset = strd_idx * strd_sz + strd_shift;
                addr = RTE_PTR_ADD(mlx5_mprq_buf_addr(buf, strd_n), offset);
                /*
                 * Memcpy packets to the target mbuf if:
                 * - The size of packet is smaller than mprq_max_memcpy_len.
                 * - Out of buffer in the Mempool for Multi-Packet RQ.
                 */
                if (len <= rxq->mprq_max_memcpy_len || rxq->mprq_repl == NULL) {
                        /*
                         * When memcpy'ing packet due to out-of-buffer, the
                         * packet must be smaller than the target mbuf.
                         */
                        if (unlikely(rte_pktmbuf_tailroom(pkt) < len)) {
                                rte_pktmbuf_free_seg(pkt);
                                ++rxq->stats.idropped;
                                continue;
                        }
                        rte_memcpy(rte_pktmbuf_mtod(pkt, void *), addr, len);
                        DATA_LEN(pkt) = len;
                } else {
                        rte_iova_t buf_iova;
                        struct rte_mbuf_ext_shared_info *shinfo;
                        uint16_t buf_len = strd_cnt * strd_sz;
                        void *buf_addr;

                        /* Increment the refcnt of the whole chunk. */
                        rte_atomic16_add_return(&buf->refcnt, 1);
                        assert((uint16_t)rte_atomic16_read(&buf->refcnt) <=
                               strd_n + 1);
                        buf_addr = RTE_PTR_SUB(addr, headroom_sz);
                        /*
                         * MLX5 device doesn't use iova but it is necessary in a
                         * case where the Rx packet is transmitted via a
                         * different PMD.
                         */
                        buf_iova = rte_mempool_virt2iova(buf) +
                                   RTE_PTR_DIFF(buf_addr, buf);
                        shinfo = &buf->shinfos[strd_idx];
                        rte_mbuf_ext_refcnt_set(shinfo, 1);
                        /*
                         * EXT_ATTACHED_MBUF will be set to pkt->ol_flags when
                         * attaching the stride to mbuf and more offload flags
                         * will be added below by calling rxq_cq_to_mbuf().
                         * Other fields will be overwritten.
                         */
                        rte_pktmbuf_attach_extbuf(pkt, buf_addr, buf_iova,
                                                  buf_len, shinfo);
                        /* Set mbuf head-room. */
                        pkt->data_off = headroom_sz;
                        assert(pkt->ol_flags == EXT_ATTACHED_MBUF);
                        /*
                         * Prevent potential overflow due to MTU change through
                         * kernel interface.
                         */
                        if (unlikely(rte_pktmbuf_tailroom(pkt) < len)) {
                                rte_pktmbuf_free_seg(pkt);
                                ++rxq->stats.idropped;
                                continue;
                        }
                        DATA_LEN(pkt) = len;
                        /*
                         * LRO packet may consume all the stride memory, in this
                         * case packet head-room space is not guaranteed so must
                         * to add an empty mbuf for the head-room.
                         */
                        if (!rxq->strd_headroom_en) {
                                struct rte_mbuf *headroom_mbuf =
                                                rte_pktmbuf_alloc(rxq->mp);

                                if (unlikely(headroom_mbuf == NULL)) {
                                        rte_pktmbuf_free_seg(pkt);
                                        ++rxq->stats.rx_nombuf;
                                        break;
                                }
                                PORT(pkt) = rxq->port_id;
                                NEXT(headroom_mbuf) = pkt;
                                pkt = headroom_mbuf;
                                NB_SEGS(pkt) = 2;
                        }
                }
                rxq_cq_to_mbuf(rxq, pkt, cqe, rss_hash_res);
                if (lro_num_seg > 1) {
                        mlx5_lro_update_hdr(addr, cqe, len);
                        pkt->ol_flags |= PKT_RX_LRO;
                        pkt->tso_segsz = strd_sz;
                }
                PKT_LEN(pkt) = len;
                PORT(pkt) = rxq->port_id;
#ifdef MLX5_PMD_SOFT_COUNTERS
                /* Increment bytes counter. */
                rxq->stats.ibytes += PKT_LEN(pkt);
#endif
                /* Return packet. */
                *(pkts++) = pkt;
                ++i;
        }
        /* Update the consumer indexes. */
        rxq->consumed_strd = consumed_strd;
        rte_cio_wmb();
        *rxq->cq_db = rte_cpu_to_be_32(rxq->cq_ci);
        if (rq_ci != rxq->rq_ci) {
                rxq->rq_ci = rq_ci;
                rte_cio_wmb();
                *rxq->rq_db = rte_cpu_to_be_32(rxq->rq_ci);
        }
#ifdef MLX5_PMD_SOFT_COUNTERS
        /* Increment packets counter. */
        rxq->stats.ipackets += i;
#endif
        return i;
}

/**
 * Dummy DPDK callback for TX.
 *
 * This function is used to temporarily replace the real callback during
 * unsafe control operations on the queue, or in case of error.
 *
 * @param dpdk_txq
 *   Generic pointer to TX queue structure.
 * @param[in] pkts
 *   Packets to transmit.
 * @param pkts_n
 *   Number of packets in array.
 *
 * @return
 *   Number of packets successfully transmitted (<= pkts_n).
 */
uint16_t
removed_tx_burst(void *dpdk_txq __rte_unused,
                 struct rte_mbuf **pkts __rte_unused,
                 uint16_t pkts_n __rte_unused)
{
        rte_mb();
        return 0;
}

/**
 * Dummy DPDK callback for RX.
 *
 * This function is used to temporarily replace the real callback during
 * unsafe control operations on the queue, or in case of error.
 *
 * @param dpdk_rxq
 *   Generic pointer to RX queue structure.
 * @param[out] pkts
 *   Array to store received packets.
 * @param pkts_n
 *   Maximum number of packets in array.
 *
 * @return
 *   Number of packets successfully received (<= pkts_n).
 */
uint16_t
removed_rx_burst(void *dpdk_txq __rte_unused,
                 struct rte_mbuf **pkts __rte_unused,
                 uint16_t pkts_n __rte_unused)
{
        rte_mb();
        return 0;
}

/*
 * Vectorized Rx/Tx routines are not compiled in when required vector
 * instructions are not supported on a target architecture. The following null
 * stubs are needed for linkage when those are not included outside of this file
 * (e.g.  mlx5_rxtx_vec_sse.c for x86).
 */

__rte_weak uint16_t
mlx5_rx_burst_vec(void *dpdk_txq __rte_unused,
                  struct rte_mbuf **pkts __rte_unused,
                  uint16_t pkts_n __rte_unused)
{
        return 0;
}

__rte_weak int
mlx5_rxq_check_vec_support(struct mlx5_rxq_data *rxq __rte_unused)
{
        return -ENOTSUP;
}

__rte_weak int
mlx5_check_vec_rx_support(struct rte_eth_dev *dev __rte_unused)
{
        return -ENOTSUP;
}

/**
 * Free the mbufs from the linear array of pointers.
 *
 * @param pkts
 *   Pointer to array of packets to be free.
 * @param pkts_n
 *   Number of packets to be freed.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 */
static __rte_always_inline void
mlx5_tx_free_mbuf(struct rte_mbuf **restrict pkts,
                  unsigned int pkts_n,
                  unsigned int olx __rte_unused)
{
        struct rte_mempool *pool = NULL;
        struct rte_mbuf **p_free = NULL;
        struct rte_mbuf *mbuf;
        unsigned int n_free = 0;

        /*
         * The implemented algorithm eliminates
         * copying pointers to temporary array
         * for rte_mempool_put_bulk() calls.
         */
        assert(pkts);
        assert(pkts_n);
        for (;;) {
                for (;;) {
                        /*
                         * Decrement mbuf reference counter, detach
                         * indirect and external buffers if needed.
                         */
                        mbuf = rte_pktmbuf_prefree_seg(*pkts);
                        if (likely(mbuf != NULL)) {
                                assert(mbuf == *pkts);
                                if (likely(n_free != 0)) {
                                        if (unlikely(pool != mbuf->pool))
                                                /* From different pool. */
                                                break;
                                } else {
                                        /* Start new scan array. */
                                        pool = mbuf->pool;
                                        p_free = pkts;
                                }
                                ++n_free;
                                ++pkts;
                                --pkts_n;
                                if (unlikely(pkts_n == 0)) {
                                        mbuf = NULL;
                                        break;
                                }
                        } else {
                                /*
                                 * This happens if mbuf is still referenced.
                                 * We can't put it back to the pool, skip.
                                 */
                                ++pkts;
                                --pkts_n;
                                if (unlikely(n_free != 0))
                                        /* There is some array to free.*/
                                        break;
                                if (unlikely(pkts_n == 0))
                                        /* Last mbuf, nothing to free. */
                                        return;
                        }
                }
                for (;;) {
                        /*
                         * This loop is implemented to avoid multiple
                         * inlining of rte_mempool_put_bulk().
                         */
                        assert(pool);
                        assert(p_free);
                        assert(n_free);
                        /*
                         * Free the array of pre-freed mbufs
                         * belonging to the same memory pool.
                         */
                        rte_mempool_put_bulk(pool, (void *)p_free, n_free);
                        if (unlikely(mbuf != NULL)) {
                                /* There is the request to start new scan. */
                                pool = mbuf->pool;
                                p_free = pkts++;
                                n_free = 1;
                                --pkts_n;
                                if (likely(pkts_n != 0))
                                        break;
                                /*
                                 * This is the last mbuf to be freed.
                                 * Do one more loop iteration to complete.
                                 * This is rare case of the last unique mbuf.
                                 */
                                mbuf = NULL;
                                continue;
                        }
                        if (likely(pkts_n == 0))
                                return;
                        n_free = 0;
                        break;
                }
        }
}

/**
 * Free the mbuf from the elts ring buffer till new tail.
 *
 * @param txq
 *   Pointer to Tx queue structure.
 * @param tail
 *   Index in elts to free up to, becomes new elts tail.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 */
static __rte_always_inline void
mlx5_tx_free_elts(struct mlx5_txq_data *restrict txq,
                  uint16_t tail,
                  unsigned int olx __rte_unused)
{
        uint16_t n_elts = tail - txq->elts_tail;

        assert(n_elts);
        assert(n_elts <= txq->elts_s);
        /*
         * Implement a loop to support ring buffer wraparound
         * with single inlining of mlx5_tx_free_mbuf().
         */
        do {
                unsigned int part;

                part = txq->elts_s - (txq->elts_tail & txq->elts_m);
                part = RTE_MIN(part, n_elts);
                assert(part);
                assert(part <= txq->elts_s);
                mlx5_tx_free_mbuf(&txq->elts[txq->elts_tail & txq->elts_m],
                                  part, olx);
                txq->elts_tail += part;
                n_elts -= part;
        } while (n_elts);
}

/**
 * Store the mbuf being sent into elts ring buffer.
 * On Tx completion these mbufs will be freed.
 *
 * @param txq
 *   Pointer to Tx queue structure.
 * @param pkts
 *   Pointer to array of packets to be stored.
 * @param pkts_n
 *   Number of packets to be stored.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 */
static __rte_always_inline void
mlx5_tx_copy_elts(struct mlx5_txq_data *restrict txq,
                  struct rte_mbuf **restrict pkts,
                  unsigned int pkts_n,
                  unsigned int olx __rte_unused)
{
        unsigned int part;
        struct rte_mbuf **elts = (struct rte_mbuf **)txq->elts;

        assert(pkts);
        assert(pkts_n);
        part = txq->elts_s - (txq->elts_head & txq->elts_m);
        assert(part);
        assert(part <= txq->elts_s);
        /* This code is a good candidate for vectorizing with SIMD. */
        rte_memcpy((void *)(elts + (txq->elts_head & txq->elts_m)),
                   (void *)pkts,
                   RTE_MIN(part, pkts_n) * sizeof(struct rte_mbuf *));
        txq->elts_head += pkts_n;
        if (unlikely(part < pkts_n))
                /* The copy is wrapping around the elts array. */
                rte_memcpy((void *)elts, (void *)(pkts + part),
                           (pkts_n - part) * sizeof(struct rte_mbuf *));
}

/**
 * Update completion queue consuming index via doorbell
 * and flush the completed data buffers.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param valid CQE pointer
 *   if not NULL update txq->wqe_pi and flush the buffers
 * @param itail
 *   if not negative - flush the buffers till this index.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 */
static __rte_always_inline void
mlx5_tx_comp_flush(struct mlx5_txq_data *restrict txq,
                   volatile struct mlx5_cqe *last_cqe,
                   int itail,
                   unsigned int olx __rte_unused)
{
        uint16_t tail;

        if (likely(last_cqe != NULL)) {
                txq->wqe_pi = rte_be_to_cpu_16(last_cqe->wqe_counter);
                tail = ((volatile struct mlx5_wqe_cseg *)
                        (txq->wqes + (txq->wqe_pi & txq->wqe_m)))->misc;
        } else if (itail >= 0) {
                tail = (uint16_t)itail;
        } else {
                return;
        }
        rte_compiler_barrier();
        *txq->cq_db = rte_cpu_to_be_32(txq->cq_ci);
        if (likely(tail != txq->elts_tail)) {
                mlx5_tx_free_elts(txq, tail, olx);
                assert(tail == txq->elts_tail);
        }
}

/**
 * Manage TX completions. This routine checks the CQ for
 * arrived CQEs, deduces the last accomplished WQE in SQ,
 * updates SQ producing index and frees all completed mbufs.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 *
 * NOTE: not inlined intentionally, it makes tx_burst
 * routine smaller, simple and faster - from experiments.
 */
static void
mlx5_tx_handle_completion(struct mlx5_txq_data *restrict txq,
                          unsigned int olx __rte_unused)
{
        unsigned int count = MLX5_TX_COMP_MAX_CQE;
        volatile struct mlx5_cqe *last_cqe = NULL;
        int ret;

        static_assert(MLX5_CQE_STATUS_HW_OWN < 0, "Must be negative value");
        static_assert(MLX5_CQE_STATUS_SW_OWN < 0, "Must be negative value");
        do {
                volatile struct mlx5_cqe *cqe;

                cqe = &txq->cqes[txq->cq_ci & txq->cqe_m];
                ret = check_cqe(cqe, txq->cqe_s, txq->cq_ci);
                if (unlikely(ret != MLX5_CQE_STATUS_SW_OWN)) {
                        if (likely(ret != MLX5_CQE_STATUS_ERR)) {
                                /* No new CQEs in completion queue. */
                                assert(ret == MLX5_CQE_STATUS_HW_OWN);
                                break;
                        }
                        /*
                         * Some error occurred, try to restart.
                         * We have no barrier after WQE related Doorbell
                         * written, make sure all writes are completed
                         * here, before we might perform SQ reset.
                         */
                        rte_wmb();
                        ret = mlx5_tx_error_cqe_handle
                                (txq, (volatile struct mlx5_err_cqe *)cqe);
                        /*
                         * Flush buffers, update consuming index
                         * if recovery succeeded. Otherwise
                         * just try to recover later.
                         */
                        last_cqe = NULL;
                        break;
                }
                /* Normal transmit completion. */
                ++txq->cq_ci;
                last_cqe = cqe;
#ifndef NDEBUG
                if (txq->cq_pi)
                        --txq->cq_pi;
#endif
        /*
         * We have to restrict the amount of processed CQEs
         * in one tx_burst routine call. The CQ may be large
         * and many CQEs may be updated by the NIC in one
         * transaction. Buffers freeing is time consuming,
         * multiple iterations may introduce significant
         * latency.
         */
        } while (--count);
        mlx5_tx_comp_flush(txq, last_cqe, ret, olx);
}

/**
 * Check if the completion request flag should be set in the last WQE.
 * Both pushed mbufs and WQEs are monitored and the completion request
 * flag is set if any of thresholds is reached.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param multi,
 *   Routine is called from multi-segment sending loop,
 *   do not correct the elts_head according to the pkts_copy.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 */
static __rte_always_inline void
mlx5_tx_request_completion(struct mlx5_txq_data *restrict txq,
                           struct mlx5_txq_local *restrict loc,
                           bool multi,
                           unsigned int olx)
{
        uint16_t head = txq->elts_head;
        unsigned int part;

        part = (MLX5_TXOFF_CONFIG(INLINE) || multi) ?
               0 : loc->pkts_sent - loc->pkts_copy;
        head += part;
        if ((uint16_t)(head - txq->elts_comp) >= MLX5_TX_COMP_THRESH ||
             (MLX5_TXOFF_CONFIG(INLINE) &&
             (uint16_t)(txq->wqe_ci - txq->wqe_comp) >= txq->wqe_thres)) {
                volatile struct mlx5_wqe *last = loc->wqe_last;

                txq->elts_comp = head;
                if (MLX5_TXOFF_CONFIG(INLINE))
                        txq->wqe_comp = txq->wqe_ci;
                /* Request unconditional completion on last WQE. */
                last->cseg.flags = RTE_BE32(MLX5_COMP_ALWAYS <<
                                            MLX5_COMP_MODE_OFFSET);
                /* Save elts_head in unused "immediate" field of WQE. */
                last->cseg.misc = head;
                /*
                 * A CQE slot must always be available. Count the
                 * issued CEQ "always" request instead of production
                 * index due to here can be CQE with errors and
                 * difference with ci may become inconsistent.
                 */
                assert(txq->cqe_s > ++txq->cq_pi);
        }
}

/**
 * DPDK callback to check the status of a tx descriptor.
 *
 * @param tx_queue
 *   The tx queue.
 * @param[in] offset
 *   The index of the descriptor in the ring.
 *
 * @return
 *   The status of the tx descriptor.
 */
int
mlx5_tx_descriptor_status(void *tx_queue, uint16_t offset)
{
        struct mlx5_txq_data *restrict txq = tx_queue;
        uint16_t used;

        mlx5_tx_handle_completion(txq, 0);
        used = txq->elts_head - txq->elts_tail;
        if (offset < used)
                return RTE_ETH_TX_DESC_FULL;
        return RTE_ETH_TX_DESC_DONE;
}

/**
 * Build the Control Segment with specified opcode:
 * - MLX5_OPCODE_SEND
 * - MLX5_OPCODE_ENHANCED_MPSW
 * - MLX5_OPCODE_TSO
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param wqe
 *   Pointer to WQE to fill with built Control Segment.
 * @param ds
 *   Supposed length of WQE in segments.
 * @param opcode
 *   SQ WQE opcode to put into Control Segment.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 */
static __rte_always_inline void
mlx5_tx_cseg_init(struct mlx5_txq_data *restrict txq,
                  struct mlx5_txq_local *restrict loc __rte_unused,
                  struct mlx5_wqe *restrict wqe,
                  unsigned int ds,
                  unsigned int opcode,
                  unsigned int olx __rte_unused)
{
        struct mlx5_wqe_cseg *restrict cs = &wqe->cseg;

        /* For legacy MPW replace the EMPW by TSO with modifier. */
        if (MLX5_TXOFF_CONFIG(MPW) && opcode == MLX5_OPCODE_ENHANCED_MPSW)
                opcode = MLX5_OPCODE_TSO | MLX5_OPC_MOD_MPW << 24;
        cs->opcode = rte_cpu_to_be_32((txq->wqe_ci << 8) | opcode);
        cs->sq_ds = rte_cpu_to_be_32(txq->qp_num_8s | ds);
        cs->flags = RTE_BE32(MLX5_COMP_ONLY_FIRST_ERR <<
                             MLX5_COMP_MODE_OFFSET);
        cs->misc = RTE_BE32(0);
}

/**
 * Build the Ethernet Segment without inlined data.
 * Supports Software Parser, Checksums and VLAN
 * insertion Tx offload features.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param wqe
 *   Pointer to WQE to fill with built Ethernet Segment.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 */
static __rte_always_inline void
mlx5_tx_eseg_none(struct mlx5_txq_data *restrict txq __rte_unused,
                  struct mlx5_txq_local *restrict loc,
                  struct mlx5_wqe *restrict wqe,
                  unsigned int olx)
{
        struct mlx5_wqe_eseg *restrict es = &wqe->eseg;
        uint32_t csum;

        /*
         * Calculate and set check sum flags first, dword field
         * in segment may be shared with Software Parser flags.
         */
        csum = MLX5_TXOFF_CONFIG(CSUM) ? txq_ol_cksum_to_cs(loc->mbuf) : 0;
        es->flags = rte_cpu_to_le_32(csum);
        /*
         * Calculate and set Software Parser offsets and flags.
         * These flags a set for custom UDP and IP tunnel packets.
         */
        es->swp_offs = txq_mbuf_to_swp(loc, &es->swp_flags, olx);
        /* Fill metadata field if needed. */
        es->metadata = MLX5_TXOFF_CONFIG(METADATA) ?
                       loc->mbuf->ol_flags & PKT_TX_DYNF_METADATA ?
                       *RTE_FLOW_DYNF_METADATA(loc->mbuf) : 0 : 0;
        /* Engage VLAN tag insertion feature if requested. */
        if (MLX5_TXOFF_CONFIG(VLAN) &&
            loc->mbuf->ol_flags & PKT_TX_VLAN_PKT) {
                /*
                 * We should get here only if device support
                 * this feature correctly.
                 */
                assert(txq->vlan_en);
                es->inline_hdr = rte_cpu_to_be_32(MLX5_ETH_WQE_VLAN_INSERT |
                                                  loc->mbuf->vlan_tci);
        } else {
                es->inline_hdr = RTE_BE32(0);
        }
}

/**
 * Build the Ethernet Segment with minimal inlined data
 * of MLX5_ESEG_MIN_INLINE_SIZE bytes length. This is
 * used to fill the gap in single WQEBB WQEs.
 * Supports Software Parser, Checksums and VLAN
 * insertion Tx offload features.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param wqe
 *   Pointer to WQE to fill with built Ethernet Segment.
 * @param vlan
 *   Length of VLAN tag insertion if any.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 */
static __rte_always_inline void
mlx5_tx_eseg_dmin(struct mlx5_txq_data *restrict txq __rte_unused,
                  struct mlx5_txq_local *restrict loc,
                  struct mlx5_wqe *restrict wqe,
                  unsigned int vlan,
                  unsigned int olx)
{
        struct mlx5_wqe_eseg *restrict es = &wqe->eseg;
        uint32_t csum;
        uint8_t *psrc, *pdst;

        /*
         * Calculate and set check sum flags first, dword field
         * in segment may be shared with Software Parser flags.
         */
        csum = MLX5_TXOFF_CONFIG(CSUM) ? txq_ol_cksum_to_cs(loc->mbuf) : 0;
        es->flags = rte_cpu_to_le_32(csum);
        /*
         * Calculate and set Software Parser offsets and flags.
         * These flags a set for custom UDP and IP tunnel packets.
         */
        es->swp_offs = txq_mbuf_to_swp(loc, &es->swp_flags, olx);
        /* Fill metadata field if needed. */
        es->metadata = MLX5_TXOFF_CONFIG(METADATA) ?
                       loc->mbuf->ol_flags & PKT_TX_DYNF_METADATA ?
                       *RTE_FLOW_DYNF_METADATA(loc->mbuf) : 0 : 0;
        static_assert(MLX5_ESEG_MIN_INLINE_SIZE ==
                                (sizeof(uint16_t) +
                                 sizeof(rte_v128u32_t)),
                      "invalid Ethernet Segment data size");
        static_assert(MLX5_ESEG_MIN_INLINE_SIZE ==
                                (sizeof(uint16_t) +
                                 sizeof(struct rte_vlan_hdr) +
                                 2 * RTE_ETHER_ADDR_LEN),
                      "invalid Ethernet Segment data size");
        psrc = rte_pktmbuf_mtod(loc->mbuf, uint8_t *);
        es->inline_hdr_sz = RTE_BE16(MLX5_ESEG_MIN_INLINE_SIZE);
        es->inline_data = *(unaligned_uint16_t *)psrc;
        psrc += sizeof(uint16_t);
        pdst = (uint8_t *)(es + 1);
        if (MLX5_TXOFF_CONFIG(VLAN) && vlan) {
                /* Implement VLAN tag insertion as part inline data. */
                memcpy(pdst, psrc, 2 * RTE_ETHER_ADDR_LEN - sizeof(uint16_t));
                pdst += 2 * RTE_ETHER_ADDR_LEN - sizeof(uint16_t);
                psrc += 2 * RTE_ETHER_ADDR_LEN - sizeof(uint16_t);
                /* Insert VLAN ethertype + VLAN tag. */
                *(unaligned_uint32_t *)pdst = rte_cpu_to_be_32
                                                ((RTE_ETHER_TYPE_VLAN << 16) |
                                                 loc->mbuf->vlan_tci);
                pdst += sizeof(struct rte_vlan_hdr);
                /* Copy the rest two bytes from packet data. */
                assert(pdst == RTE_PTR_ALIGN(pdst, sizeof(uint16_t)));
                *(uint16_t *)pdst = *(unaligned_uint16_t *)psrc;
        } else {
                /* Fill the gap in the title WQEBB with inline data. */
                rte_mov16(pdst, psrc);
        }
}

/**
 * Build the Ethernet Segment with entire packet
 * data inlining. Checks the boundary of WQEBB and
 * ring buffer wrapping, supports Software Parser,
 * Checksums and VLAN insertion Tx offload features.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param wqe
 *   Pointer to WQE to fill with built Ethernet Segment.
 * @param vlan
 *   Length of VLAN tag insertion if any.
 * @param inlen
 *   Length of data to inline (VLAN included, if any).
 * @param tso
 *   TSO flag, set mss field from the packet.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 *
 * @return
 *   Pointer to the next Data Segment (aligned and wrapped around).
 */
static __rte_always_inline struct mlx5_wqe_dseg *
mlx5_tx_eseg_data(struct mlx5_txq_data *restrict txq,
                  struct mlx5_txq_local *restrict loc,
                  struct mlx5_wqe *restrict wqe,
                  unsigned int vlan,
                  unsigned int inlen,
                  unsigned int tso,
                  unsigned int olx)
{
        struct mlx5_wqe_eseg *restrict es = &wqe->eseg;
        uint32_t csum;
        uint8_t *psrc, *pdst;
        unsigned int part;

        /*
         * Calculate and set check sum flags first, dword field
         * in segment may be shared with Software Parser flags.
         */
        csum = MLX5_TXOFF_CONFIG(CSUM) ? txq_ol_cksum_to_cs(loc->mbuf) : 0;
        if (tso) {
                csum <<= 24;
                csum |= loc->mbuf->tso_segsz;
                es->flags = rte_cpu_to_be_32(csum);
        } else {
                es->flags = rte_cpu_to_le_32(csum);
        }
        /*
         * Calculate and set Software Parser offsets and flags.
         * These flags a set for custom UDP and IP tunnel packets.
         */
        es->swp_offs = txq_mbuf_to_swp(loc, &es->swp_flags, olx);
        /* Fill metadata field if needed. */
        es->metadata = MLX5_TXOFF_CONFIG(METADATA) ?
                       loc->mbuf->ol_flags & PKT_TX_DYNF_METADATA ?
                       *RTE_FLOW_DYNF_METADATA(loc->mbuf) : 0 : 0;
        static_assert(MLX5_ESEG_MIN_INLINE_SIZE ==
                                (sizeof(uint16_t) +
                                 sizeof(rte_v128u32_t)),
                      "invalid Ethernet Segment data size");
        static_assert(MLX5_ESEG_MIN_INLINE_SIZE ==
                                (sizeof(uint16_t) +
                                 sizeof(struct rte_vlan_hdr) +
                                 2 * RTE_ETHER_ADDR_LEN),
                      "invalid Ethernet Segment data size");
        psrc = rte_pktmbuf_mtod(loc->mbuf, uint8_t *);
        es->inline_hdr_sz = rte_cpu_to_be_16(inlen);
        es->inline_data = *(unaligned_uint16_t *)psrc;
        psrc += sizeof(uint16_t);
        pdst = (uint8_t *)(es + 1);
        if (MLX5_TXOFF_CONFIG(VLAN) && vlan) {
                /* Implement VLAN tag insertion as part inline data. */
                memcpy(pdst, psrc, 2 * RTE_ETHER_ADDR_LEN - sizeof(uint16_t));
                pdst += 2 * RTE_ETHER_ADDR_LEN - sizeof(uint16_t);
                psrc += 2 * RTE_ETHER_ADDR_LEN - sizeof(uint16_t);
                /* Insert VLAN ethertype + VLAN tag. */
                *(unaligned_uint32_t *)pdst = rte_cpu_to_be_32
                                                ((RTE_ETHER_TYPE_VLAN << 16) |
                                                 loc->mbuf->vlan_tci);
                pdst += sizeof(struct rte_vlan_hdr);
                /* Copy the rest two bytes from packet data. */
                assert(pdst == RTE_PTR_ALIGN(pdst, sizeof(uint16_t)));
                *(uint16_t *)pdst = *(unaligned_uint16_t *)psrc;
                psrc += sizeof(uint16_t);
        } else {
                /* Fill the gap in the title WQEBB with inline data. */
                rte_mov16(pdst, psrc);
                psrc += sizeof(rte_v128u32_t);
        }
        pdst = (uint8_t *)(es + 2);
        assert(inlen >= MLX5_ESEG_MIN_INLINE_SIZE);
        assert(pdst < (uint8_t *)txq->wqes_end);
        inlen -= MLX5_ESEG_MIN_INLINE_SIZE;
        if (!inlen) {
                assert(pdst == RTE_PTR_ALIGN(pdst, MLX5_WSEG_SIZE));
                return (struct mlx5_wqe_dseg *)pdst;
        }
        /*
         * The WQEBB space availability is checked by caller.
         * Here we should be aware of WQE ring buffer wraparound only.
         */
        part = (uint8_t *)txq->wqes_end - pdst;
        part = RTE_MIN(part, inlen);
        do {
                rte_memcpy(pdst, psrc, part);
                inlen -= part;
                if (likely(!inlen)) {
                        /*
                         * If return value is not used by the caller
                         * the code below will be optimized out.
                         */
                        pdst += part;
                        pdst = RTE_PTR_ALIGN(pdst, MLX5_WSEG_SIZE);
                        if (unlikely(pdst >= (uint8_t *)txq->wqes_end))
                                pdst = (uint8_t *)txq->wqes;
                        return (struct mlx5_wqe_dseg *)pdst;
                }
                pdst = (uint8_t *)txq->wqes;
                psrc += part;
                part = inlen;
        } while (true);
}

/**
 * Copy data from chain of mbuf to the specified linear buffer.
 * Checksums and VLAN insertion Tx offload features. If data
 * from some mbuf copied completely this mbuf is freed. Local
 * structure is used to keep the byte stream state.
 *
 * @param pdst
 *   Pointer to the destination linear buffer.
 * @param loc
 *   Pointer to burst routine local context.
 * @param len
 *   Length of data to be copied.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 */
static __rte_always_inline void
mlx5_tx_mseg_memcpy(uint8_t *pdst,
                    struct mlx5_txq_local *restrict loc,
                    unsigned int len,
                    unsigned int olx __rte_unused)
{
        struct rte_mbuf *mbuf;
        unsigned int part, dlen;
        uint8_t *psrc;

        assert(len);
        do {
                /* Allow zero length packets, must check first. */
                dlen = rte_pktmbuf_data_len(loc->mbuf);
                if (dlen <= loc->mbuf_off) {
                        /* Exhausted packet, just free. */
                        mbuf = loc->mbuf;
                        loc->mbuf = mbuf->next;
                        rte_pktmbuf_free_seg(mbuf);
                        loc->mbuf_off = 0;
                        assert(loc->mbuf_nseg > 1);
                        assert(loc->mbuf);
                        --loc->mbuf_nseg;
                        continue;
                }
                dlen -= loc->mbuf_off;
                psrc = rte_pktmbuf_mtod_offset(loc->mbuf, uint8_t *,
                                               loc->mbuf_off);
                part = RTE_MIN(len, dlen);
                rte_memcpy(pdst, psrc, part);
                loc->mbuf_off += part;
                len -= part;
                if (!len) {
                        if (loc->mbuf_off >= rte_pktmbuf_data_len(loc->mbuf)) {
                                loc->mbuf_off = 0;
                                /* Exhausted packet, just free. */
                                mbuf = loc->mbuf;
                                loc->mbuf = mbuf->next;
                                rte_pktmbuf_free_seg(mbuf);
                                loc->mbuf_off = 0;
                                assert(loc->mbuf_nseg >= 1);
                                --loc->mbuf_nseg;
                        }
                        return;
                }
                pdst += part;
        } while (true);
}

/**
 * Build the Ethernet Segment with inlined data from
 * multi-segment packet. Checks the boundary of WQEBB
 * and ring buffer wrapping, supports Software Parser,
 * Checksums and VLAN insertion Tx offload features.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param wqe
 *   Pointer to WQE to fill with built Ethernet Segment.
 * @param vlan
 *   Length of VLAN tag insertion if any.
 * @param inlen
 *   Length of data to inline (VLAN included, if any).
 * @param tso
 *   TSO flag, set mss field from the packet.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 *
 * @return
 *   Pointer to the next Data Segment (aligned and
 *   possible NOT wrapped around - caller should do
 *   wrapping check on its own).
 */
static __rte_always_inline struct mlx5_wqe_dseg *
mlx5_tx_eseg_mdat(struct mlx5_txq_data *restrict txq,
                  struct mlx5_txq_local *restrict loc,
                  struct mlx5_wqe *restrict wqe,
                  unsigned int vlan,
                  unsigned int inlen,
                  unsigned int tso,
                  unsigned int olx)
{
        struct mlx5_wqe_eseg *restrict es = &wqe->eseg;
        uint32_t csum;
        uint8_t *pdst;
        unsigned int part;

        /*
         * Calculate and set check sum flags first, uint32_t field
         * in segment may be shared with Software Parser flags.
         */
        csum = MLX5_TXOFF_CONFIG(CSUM) ? txq_ol_cksum_to_cs(loc->mbuf) : 0;
        if (tso) {
                csum <<= 24;
                csum |= loc->mbuf->tso_segsz;
                es->flags = rte_cpu_to_be_32(csum);
        } else {
                es->flags = rte_cpu_to_le_32(csum);
        }
        /*
         * Calculate and set Software Parser offsets and flags.
         * These flags a set for custom UDP and IP tunnel packets.
         */
        es->swp_offs = txq_mbuf_to_swp(loc, &es->swp_flags, olx);
        /* Fill metadata field if needed. */
        es->metadata = MLX5_TXOFF_CONFIG(METADATA) ?
                       loc->mbuf->ol_flags & PKT_TX_DYNF_METADATA ?
                       *RTE_FLOW_DYNF_METADATA(loc->mbuf) : 0 : 0;
        static_assert(MLX5_ESEG_MIN_INLINE_SIZE ==
                                (sizeof(uint16_t) +
                                 sizeof(rte_v128u32_t)),
                      "invalid Ethernet Segment data size");
        static_assert(MLX5_ESEG_MIN_INLINE_SIZE ==
                                (sizeof(uint16_t) +
                                 sizeof(struct rte_vlan_hdr) +
                                 2 * RTE_ETHER_ADDR_LEN),
                      "invalid Ethernet Segment data size");
        assert(inlen >= MLX5_ESEG_MIN_INLINE_SIZE);
        es->inline_hdr_sz = rte_cpu_to_be_16(inlen);
        pdst = (uint8_t *)&es->inline_data;
        if (MLX5_TXOFF_CONFIG(VLAN) && vlan) {
                /* Implement VLAN tag insertion as part inline data. */
                mlx5_tx_mseg_memcpy(pdst, loc, 2 * RTE_ETHER_ADDR_LEN, olx);
                pdst += 2 * RTE_ETHER_ADDR_LEN;
                *(unaligned_uint32_t *)pdst = rte_cpu_to_be_32
                                                ((RTE_ETHER_TYPE_VLAN << 16) |
                                                 loc->mbuf->vlan_tci);
                pdst += sizeof(struct rte_vlan_hdr);
                inlen -= 2 * RTE_ETHER_ADDR_LEN + sizeof(struct rte_vlan_hdr);
        }
        assert(pdst < (uint8_t *)txq->wqes_end);
        /*
         * The WQEBB space availability is checked by caller.
         * Here we should be aware of WQE ring buffer wraparound only.
         */
        part = (uint8_t *)txq->wqes_end - pdst;
        part = RTE_MIN(part, inlen);
        assert(part);
        do {
                mlx5_tx_mseg_memcpy(pdst, loc, part, olx);
                inlen -= part;
                if (likely(!inlen)) {
                        pdst += part;
                        pdst = RTE_PTR_ALIGN(pdst, MLX5_WSEG_SIZE);
                        return (struct mlx5_wqe_dseg *)pdst;
                }
                pdst = (uint8_t *)txq->wqes;
                part = inlen;
        } while (true);
}

/**
 * Build the Data Segment of pointer type.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param dseg
 *   Pointer to WQE to fill with built Data Segment.
 * @param buf
 *   Data buffer to point.
 * @param len
 *   Data buffer length.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 */
static __rte_always_inline void
mlx5_tx_dseg_ptr(struct mlx5_txq_data *restrict txq,
                 struct mlx5_txq_local *restrict loc,
                 struct mlx5_wqe_dseg *restrict dseg,
                 uint8_t *buf,
                 unsigned int len,
                 unsigned int olx __rte_unused)

{
        assert(len);
        dseg->bcount = rte_cpu_to_be_32(len);
        dseg->lkey = mlx5_tx_mb2mr(txq, loc->mbuf);
        dseg->pbuf = rte_cpu_to_be_64((uintptr_t)buf);
}

/**
 * Build the Data Segment of pointer type or inline
 * if data length is less than buffer in minimal
 * Data Segment size.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param dseg
 *   Pointer to WQE to fill with built Data Segment.
 * @param buf
 *   Data buffer to point.
 * @param len
 *   Data buffer length.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 */
static __rte_always_inline void
mlx5_tx_dseg_iptr(struct mlx5_txq_data *restrict txq,
                  struct mlx5_txq_local *restrict loc,
                  struct mlx5_wqe_dseg *restrict dseg,
                  uint8_t *buf,
                  unsigned int len,
                  unsigned int olx __rte_unused)

{
        uintptr_t dst, src;

        assert(len);
        if (len > MLX5_DSEG_MIN_INLINE_SIZE) {
                dseg->bcount = rte_cpu_to_be_32(len);
                dseg->lkey = mlx5_tx_mb2mr(txq, loc->mbuf);
                dseg->pbuf = rte_cpu_to_be_64((uintptr_t)buf);

                return;
        }
        dseg->bcount = rte_cpu_to_be_32(len | MLX5_ETH_WQE_DATA_INLINE);
        /* Unrolled implementation of generic rte_memcpy. */
        dst = (uintptr_t)&dseg->inline_data[0];
        src = (uintptr_t)buf;
        if (len & 0x08) {
#ifdef RTE_ARCH_STRICT_ALIGN
                assert(dst == RTE_PTR_ALIGN(dst, sizeof(uint32_t)));
                *(uint32_t *)dst = *(unaligned_uint32_t *)src;
                dst += sizeof(uint32_t);
                src += sizeof(uint32_t);
                *(uint32_t *)dst = *(unaligned_uint32_t *)src;
                dst += sizeof(uint32_t);
                src += sizeof(uint32_t);
#else
                *(uint64_t *)dst = *(unaligned_uint64_t *)src;
                dst += sizeof(uint64_t);
                src += sizeof(uint64_t);
#endif
        }
        if (len & 0x04) {
                *(uint32_t *)dst = *(unaligned_uint32_t *)src;
                dst += sizeof(uint32_t);
                src += sizeof(uint32_t);
        }
        if (len & 0x02) {
                *(uint16_t *)dst = *(unaligned_uint16_t *)src;
                dst += sizeof(uint16_t);
                src += sizeof(uint16_t);
        }
        if (len & 0x01)
                *(uint8_t *)dst = *(uint8_t *)src;
}

/**
 * Build the Data Segment of inlined data from single
 * segment packet, no VLAN insertion.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param dseg
 *   Pointer to WQE to fill with built Data Segment.
 * @param buf
 *   Data buffer to point.
 * @param len
 *   Data buffer length.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 *
 * @return
 *   Pointer to the next Data Segment after inlined data.
 *   Ring buffer wraparound check is needed. We do not
 *   do it here because it may not be needed for the
 *   last packet in the eMPW session.
 */
static __rte_always_inline struct mlx5_wqe_dseg *
mlx5_tx_dseg_empw(struct mlx5_txq_data *restrict txq,
                  struct mlx5_txq_local *restrict loc __rte_unused,
                  struct mlx5_wqe_dseg *restrict dseg,
                  uint8_t *buf,
                  unsigned int len,
                  unsigned int olx __rte_unused)
{
        unsigned int part;
        uint8_t *pdst;

        dseg->bcount = rte_cpu_to_be_32(len | MLX5_ETH_WQE_DATA_INLINE);
        pdst = &dseg->inline_data[0];
        /*
         * The WQEBB space availability is checked by caller.
         * Here we should be aware of WQE ring buffer wraparound only.
         */
        part = (uint8_t *)txq->wqes_end - pdst;
        part = RTE_MIN(part, len);
        do {
                rte_memcpy(pdst, buf, part);
                len -= part;
                if (likely(!len)) {
                        pdst += part;
                        pdst = RTE_PTR_ALIGN(pdst, MLX5_WSEG_SIZE);
                        /* Note: no final wraparound check here. */
                        return (struct mlx5_wqe_dseg *)pdst;
                }
                pdst = (uint8_t *)txq->wqes;
                buf += part;
                part = len;
        } while (true);
}

/**
 * Build the Data Segment of inlined data from single
 * segment packet with VLAN insertion.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param dseg
 *   Pointer to the dseg fill with built Data Segment.
 * @param buf
 *   Data buffer to point.
 * @param len
 *   Data buffer length.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 *
 * @return
 *   Pointer to the next Data Segment after inlined data.
 *   Ring buffer wraparound check is needed.
 */
static __rte_always_inline struct mlx5_wqe_dseg *
mlx5_tx_dseg_vlan(struct mlx5_txq_data *restrict txq,
                  struct mlx5_txq_local *restrict loc __rte_unused,
                  struct mlx5_wqe_dseg *restrict dseg,
                  uint8_t *buf,
                  unsigned int len,
                  unsigned int olx __rte_unused)

{
        unsigned int part;
        uint8_t *pdst;

        assert(len > MLX5_ESEG_MIN_INLINE_SIZE);
        static_assert(MLX5_DSEG_MIN_INLINE_SIZE ==
                                 (2 * RTE_ETHER_ADDR_LEN),
                      "invalid Data Segment data size");
        dseg->bcount = rte_cpu_to_be_32((len + sizeof(struct rte_vlan_hdr)) |
                                        MLX5_ETH_WQE_DATA_INLINE);
        pdst = &dseg->inline_data[0];
        memcpy(pdst, buf, MLX5_DSEG_MIN_INLINE_SIZE);
        buf += MLX5_DSEG_MIN_INLINE_SIZE;
        pdst += MLX5_DSEG_MIN_INLINE_SIZE;
        len -= MLX5_DSEG_MIN_INLINE_SIZE;
        /* Insert VLAN ethertype + VLAN tag. Pointer is aligned. */
        assert(pdst == RTE_PTR_ALIGN(pdst, MLX5_WSEG_SIZE));
        if (unlikely(pdst >= (uint8_t *)txq->wqes_end))
                pdst = (uint8_t *)txq->wqes;
        *(uint32_t *)pdst = rte_cpu_to_be_32((RTE_ETHER_TYPE_VLAN << 16) |
                                              loc->mbuf->vlan_tci);
        pdst += sizeof(struct rte_vlan_hdr);
        /*
         * The WQEBB space availability is checked by caller.
         * Here we should be aware of WQE ring buffer wraparound only.
         */
        part = (uint8_t *)txq->wqes_end - pdst;
        part = RTE_MIN(part, len);
        do {
                rte_memcpy(pdst, buf, part);
                len -= part;
                if (likely(!len)) {
                        pdst += part;
                        pdst = RTE_PTR_ALIGN(pdst, MLX5_WSEG_SIZE);
                        /* Note: no final wraparound check here. */
                        return (struct mlx5_wqe_dseg *)pdst;
                }
                pdst = (uint8_t *)txq->wqes;
                buf += part;
                part = len;
        } while (true);
}

/**
 * Build the Ethernet Segment with optionally inlined data with
 * VLAN insertion and following Data Segments (if any) from
 * multi-segment packet. Used by ordinary send and TSO.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param wqe
 *   Pointer to WQE to fill with built Ethernet/Data Segments.
 * @param vlan
 *   Length of VLAN header to insert, 0 means no VLAN insertion.
 * @param inlen
 *   Data length to inline. For TSO this parameter specifies
 *   exact value, for ordinary send routine can be aligned by
 *   caller to provide better WQE space saving and data buffer
 *   start address alignment. This length includes VLAN header
 *   being inserted.
 * @param tso
 *   Zero means ordinary send, inlined data can be extended,
 *   otherwise this is TSO, inlined data length is fixed.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 *
 * @return
 *   Actual size of built WQE in segments.
 */
static __rte_always_inline unsigned int
mlx5_tx_mseg_build(struct mlx5_txq_data *restrict txq,
                   struct mlx5_txq_local *restrict loc,
                   struct mlx5_wqe *restrict wqe,
                   unsigned int vlan,
                   unsigned int inlen,
                   unsigned int tso,
                   unsigned int olx __rte_unused)
{
        struct mlx5_wqe_dseg *restrict dseg;
        unsigned int ds;

        assert((rte_pktmbuf_pkt_len(loc->mbuf) + vlan) >= inlen);
        loc->mbuf_nseg = NB_SEGS(loc->mbuf);
        loc->mbuf_off = 0;

        dseg = mlx5_tx_eseg_mdat(txq, loc, wqe, vlan, inlen, tso, olx);
        if (!loc->mbuf_nseg)
                goto dseg_done;
        /*
         * There are still some mbuf remaining, not inlined.
         * The first mbuf may be partially inlined and we
         * must process the possible non-zero data offset.
         */
        if (loc->mbuf_off) {
                unsigned int dlen;
                uint8_t *dptr;

                /*
                 * Exhausted packets must be dropped before.
                 * Non-zero offset means there are some data
                 * remained in the packet.
                 */
                assert(loc->mbuf_off < rte_pktmbuf_data_len(loc->mbuf));
                assert(rte_pktmbuf_data_len(loc->mbuf));
                dptr = rte_pktmbuf_mtod_offset(loc->mbuf, uint8_t *,
                                               loc->mbuf_off);
                dlen = rte_pktmbuf_data_len(loc->mbuf) - loc->mbuf_off;
                /*
                 * Build the pointer/minimal data Data Segment.
                 * Do ring buffer wrapping check in advance.
                 */
                if ((uintptr_t)dseg >= (uintptr_t)txq->wqes_end)
                        dseg = (struct mlx5_wqe_dseg *)txq->wqes;
                mlx5_tx_dseg_iptr(txq, loc, dseg, dptr, dlen, olx);
                /* Store the mbuf to be freed on completion. */
                assert(loc->elts_free);
                txq->elts[txq->elts_head++ & txq->elts_m] = loc->mbuf;
                --loc->elts_free;
                ++dseg;
                if (--loc->mbuf_nseg == 0)
                        goto dseg_done;
                loc->mbuf = loc->mbuf->next;
                loc->mbuf_off = 0;
        }
        do {
                if (unlikely(!rte_pktmbuf_data_len(loc->mbuf))) {
                        struct rte_mbuf *mbuf;

                        /* Zero length segment found, just skip. */
                        mbuf = loc->mbuf;
                        loc->mbuf = loc->mbuf->next;
                        rte_pktmbuf_free_seg(mbuf);
                        if (--loc->mbuf_nseg == 0)
                                break;
                } else {
                        if ((uintptr_t)dseg >= (uintptr_t)txq->wqes_end)
                                dseg = (struct mlx5_wqe_dseg *)txq->wqes;
                        mlx5_tx_dseg_iptr
                                (txq, loc, dseg,
                                 rte_pktmbuf_mtod(loc->mbuf, uint8_t *),
                                 rte_pktmbuf_data_len(loc->mbuf), olx);
                        assert(loc->elts_free);
                        txq->elts[txq->elts_head++ & txq->elts_m] = loc->mbuf;
                        --loc->elts_free;
                        ++dseg;
                        if (--loc->mbuf_nseg == 0)
                                break;
                        loc->mbuf = loc->mbuf->next;
                }
        } while (true);

dseg_done:
        /* Calculate actual segments used from the dseg pointer. */
        if ((uintptr_t)wqe < (uintptr_t)dseg)
                ds = ((uintptr_t)dseg - (uintptr_t)wqe) / MLX5_WSEG_SIZE;
        else
                ds = (((uintptr_t)dseg - (uintptr_t)wqe) +
                      txq->wqe_s * MLX5_WQE_SIZE) / MLX5_WSEG_SIZE;
        return ds;
}

/**
 * Tx one packet function for multi-segment TSO. Supports all
 * types of Tx offloads, uses MLX5_OPCODE_TSO to build WQEs,
 * sends one packet per WQE.
 *
 * This routine is responsible for storing processed mbuf
 * into elts ring buffer and update elts_head.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 *
 * @return
 *   MLX5_TXCMP_CODE_EXIT - sending is done or impossible.
 *   MLX5_TXCMP_CODE_ERROR - some unrecoverable error occurred.
 * Local context variables partially updated.
 */
static __rte_always_inline enum mlx5_txcmp_code
mlx5_tx_packet_multi_tso(struct mlx5_txq_data *restrict txq,
                        struct mlx5_txq_local *restrict loc,
                        unsigned int olx)
{
        struct mlx5_wqe *restrict wqe;
        unsigned int ds, dlen, inlen, ntcp, vlan = 0;

        /*
         * Calculate data length to be inlined to estimate
         * the required space in WQE ring buffer.
         */
        dlen = rte_pktmbuf_pkt_len(loc->mbuf);
        if (MLX5_TXOFF_CONFIG(VLAN) && loc->mbuf->ol_flags & PKT_TX_VLAN_PKT)
                vlan = sizeof(struct rte_vlan_hdr);
        inlen = loc->mbuf->l2_len + vlan +
                loc->mbuf->l3_len + loc->mbuf->l4_len;
        if (unlikely((!inlen || !loc->mbuf->tso_segsz)))
                return MLX5_TXCMP_CODE_ERROR;
        if (loc->mbuf->ol_flags & PKT_TX_TUNNEL_MASK)
                inlen += loc->mbuf->outer_l2_len + loc->mbuf->outer_l3_len;
        /* Packet must contain all TSO headers. */
        if (unlikely(inlen > MLX5_MAX_TSO_HEADER ||
                     inlen <= MLX5_ESEG_MIN_INLINE_SIZE ||
                     inlen > (dlen + vlan)))
                return MLX5_TXCMP_CODE_ERROR;
        assert(inlen >= txq->inlen_mode);
        /*
         * Check whether there are enough free WQEBBs:
         * - Control Segment
         * - Ethernet Segment
         * - First Segment of inlined Ethernet data
         * - ... data continued ...
         * - Data Segments of pointer/min inline type
         */
        ds = NB_SEGS(loc->mbuf) + 2 + (inlen -
                                       MLX5_ESEG_MIN_INLINE_SIZE +
                                       MLX5_WSEG_SIZE +
                                       MLX5_WSEG_SIZE - 1) / MLX5_WSEG_SIZE;
        if (unlikely(loc->wqe_free < ((ds + 3) / 4)))
                return MLX5_TXCMP_CODE_EXIT;
        /* Check for maximal WQE size. */
        if (unlikely((MLX5_WQE_SIZE_MAX / MLX5_WSEG_SIZE) < ((ds + 3) / 4)))
                return MLX5_TXCMP_CODE_ERROR;
#ifdef MLX5_PMD_SOFT_COUNTERS
        /* Update sent data bytes/packets counters. */
        ntcp = (dlen - (inlen - vlan) + loc->mbuf->tso_segsz - 1) /
                loc->mbuf->tso_segsz;
        /*
         * One will be added for mbuf itself
         * at the end of the mlx5_tx_burst from
         * loc->pkts_sent field.
         */
        --ntcp;
        txq->stats.opackets += ntcp;
        txq->stats.obytes += dlen + vlan + ntcp * inlen;
#endif
        wqe = txq->wqes + (txq->wqe_ci & txq->wqe_m);
        loc->wqe_last = wqe;
        mlx5_tx_cseg_init(txq, loc, wqe, 0, MLX5_OPCODE_TSO, olx);
        ds = mlx5_tx_mseg_build(txq, loc, wqe, vlan, inlen, 1, olx);
        wqe->cseg.sq_ds = rte_cpu_to_be_32(txq->qp_num_8s | ds);
        txq->wqe_ci += (ds + 3) / 4;
        loc->wqe_free -= (ds + 3) / 4;
        /* Request CQE generation if limits are reached. */
        mlx5_tx_request_completion(txq, loc, true, olx);
        return MLX5_TXCMP_CODE_MULTI;
}

/**
 * Tx one packet function for multi-segment SEND. Supports all
 * types of Tx offloads, uses MLX5_OPCODE_SEND to build WQEs,
 * sends one packet per WQE, without any data inlining in
 * Ethernet Segment.
 *
 * This routine is responsible for storing processed mbuf
 * into elts ring buffer and update elts_head.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 *
 * @return
 *   MLX5_TXCMP_CODE_EXIT - sending is done or impossible.
 *   MLX5_TXCMP_CODE_ERROR - some unrecoverable error occurred.
 * Local context variables partially updated.
 */
static __rte_always_inline enum mlx5_txcmp_code
mlx5_tx_packet_multi_send(struct mlx5_txq_data *restrict txq,
                          struct mlx5_txq_local *restrict loc,
                          unsigned int olx)
{
        struct mlx5_wqe_dseg *restrict dseg;
        struct mlx5_wqe *restrict wqe;
        unsigned int ds, nseg;

        assert(NB_SEGS(loc->mbuf) > 1);
        /*
         * No inline at all, it means the CPU cycles saving
         * is prioritized at configuration, we should not
         * copy any packet data to WQE.
         */
        nseg = NB_SEGS(loc->mbuf);
        ds = 2 + nseg;
        if (unlikely(loc->wqe_free < ((ds + 3) / 4)))
                return MLX5_TXCMP_CODE_EXIT;
        /* Check for maximal WQE size. */
        if (unlikely((MLX5_WQE_SIZE_MAX / MLX5_WSEG_SIZE) < ((ds + 3) / 4)))
                return MLX5_TXCMP_CODE_ERROR;
        /*
         * Some Tx offloads may cause an error if
         * packet is not long enough, check against
         * assumed minimal length.
         */
        if (rte_pktmbuf_pkt_len(loc->mbuf) <= MLX5_ESEG_MIN_INLINE_SIZE)
                return MLX5_TXCMP_CODE_ERROR;
#ifdef MLX5_PMD_SOFT_COUNTERS
        /* Update sent data bytes counter. */
        txq->stats.obytes += rte_pktmbuf_pkt_len(loc->mbuf);
        if (MLX5_TXOFF_CONFIG(VLAN) &&
            loc->mbuf->ol_flags & PKT_TX_VLAN_PKT)
                txq->stats.obytes += sizeof(struct rte_vlan_hdr);
#endif
        /*
         * SEND WQE, one WQEBB:
         * - Control Segment, SEND opcode
         * - Ethernet Segment, optional VLAN, no inline
         * - Data Segments, pointer only type
         */
        wqe = txq->wqes + (txq->wqe_ci & txq->wqe_m);
        loc->wqe_last = wqe;
        mlx5_tx_cseg_init(txq, loc, wqe, ds, MLX5_OPCODE_SEND, olx);
        mlx5_tx_eseg_none(txq, loc, wqe, olx);
        dseg = &wqe->dseg[0];
        do {
                if (unlikely(!rte_pktmbuf_data_len(loc->mbuf))) {
                        struct rte_mbuf *mbuf;

                        /*
                         * Zero length segment found, have to
                         * correct total size of WQE in segments.
                         * It is supposed to be rare occasion, so
                         * in normal case (no zero length segments)
                         * we avoid extra writing to the Control
                         * Segment.
                         */
                        --ds;
                        wqe->cseg.sq_ds -= RTE_BE32(1);
                        mbuf = loc->mbuf;
                        loc->mbuf = mbuf->next;
                        rte_pktmbuf_free_seg(mbuf);
                        if (--nseg == 0)
                                break;
                } else {
                        mlx5_tx_dseg_ptr
                                (txq, loc, dseg,
                                 rte_pktmbuf_mtod(loc->mbuf, uint8_t *),
                                 rte_pktmbuf_data_len(loc->mbuf), olx);
                        txq->elts[txq->elts_head++ & txq->elts_m] = loc->mbuf;
                        --loc->elts_free;
                        if (--nseg == 0)
                                break;
                        ++dseg;
                        if ((uintptr_t)dseg >= (uintptr_t)txq->wqes_end)
                                dseg = (struct mlx5_wqe_dseg *)txq->wqes;
                        loc->mbuf = loc->mbuf->next;
                }
        } while (true);
        txq->wqe_ci += (ds + 3) / 4;
        loc->wqe_free -= (ds + 3) / 4;
        /* Request CQE generation if limits are reached. */
        mlx5_tx_request_completion(txq, loc, true, olx);
        return MLX5_TXCMP_CODE_MULTI;
}

/**
 * Tx one packet function for multi-segment SEND. Supports all
 * types of Tx offloads, uses MLX5_OPCODE_SEND to build WQEs,
 * sends one packet per WQE, with data inlining in
 * Ethernet Segment and minimal Data Segments.
 *
 * This routine is responsible for storing processed mbuf
 * into elts ring buffer and update elts_head.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 *
 * @return
 *   MLX5_TXCMP_CODE_EXIT - sending is done or impossible.
 *   MLX5_TXCMP_CODE_ERROR - some unrecoverable error occurred.
 * Local context variables partially updated.
 */
static __rte_always_inline enum mlx5_txcmp_code
mlx5_tx_packet_multi_inline(struct mlx5_txq_data *restrict txq,
                            struct mlx5_txq_local *restrict loc,
                            unsigned int olx)
{
        struct mlx5_wqe *restrict wqe;
        unsigned int ds, inlen, dlen, vlan = 0;

        assert(MLX5_TXOFF_CONFIG(INLINE));
        assert(NB_SEGS(loc->mbuf) > 1);
        /*
         * First calculate data length to be inlined
         * to estimate the required space for WQE.
         */
        dlen = rte_pktmbuf_pkt_len(loc->mbuf);
        if (MLX5_TXOFF_CONFIG(VLAN) && loc->mbuf->ol_flags & PKT_TX_VLAN_PKT)
                vlan = sizeof(struct rte_vlan_hdr);
        inlen = dlen + vlan;
        /* Check against minimal length. */
        if (inlen <= MLX5_ESEG_MIN_INLINE_SIZE)
                return MLX5_TXCMP_CODE_ERROR;
        assert(txq->inlen_send >= MLX5_ESEG_MIN_INLINE_SIZE);
        if (inlen > txq->inlen_send) {
                struct rte_mbuf *mbuf;
                unsigned int nxlen;
                uintptr_t start;

                /*
                 * Packet length exceeds the allowed inline
                 * data length, check whether the minimal
                 * inlining is required.
                 */
                if (txq->inlen_mode) {
                        assert(txq->inlen_mode >= MLX5_ESEG_MIN_INLINE_SIZE);
                        assert(txq->inlen_mode <= txq->inlen_send);
                        inlen = txq->inlen_mode;
                } else {
                        if (!vlan || txq->vlan_en) {
                                /*
                                 * VLAN insertion will be done inside by HW.
                                 * It is not utmost effective - VLAN flag is
                                 * checked twice, but we should proceed the
                                 * inlining length correctly and take into
                                 * account the VLAN header being inserted.
                                 */
                                return mlx5_tx_packet_multi_send
                                                        (txq, loc, olx);
                        }
                        inlen = MLX5_ESEG_MIN_INLINE_SIZE;
                }
                /*
                 * Now we know the minimal amount of data is requested
                 * to inline. Check whether we should inline the buffers
                 * from the chain beginning to eliminate some mbufs.
                 */
                mbuf = loc->mbuf;
                nxlen = rte_pktmbuf_data_len(mbuf);
                if (unlikely(nxlen <= txq->inlen_send)) {
                        /* We can inline first mbuf at least. */
                        if (nxlen < inlen) {
                                unsigned int smlen;

                                /* Scan mbufs till inlen filled. */
                                do {
                                        smlen = nxlen;
                                        mbuf = NEXT(mbuf);
                                        assert(mbuf);
                                        nxlen = rte_pktmbuf_data_len(mbuf);
                                        nxlen += smlen;
                                } while (unlikely(nxlen < inlen));
                                if (unlikely(nxlen > txq->inlen_send)) {
                                        /* We cannot inline entire mbuf. */
                                        smlen = inlen - smlen;
                                        start = rte_pktmbuf_mtod_offset
                                                    (mbuf, uintptr_t, smlen);
                                        goto do_align;
                                }
                        }
                        do {
                                inlen = nxlen;
                                mbuf = NEXT(mbuf);
                                /* There should be not end of packet. */
                                assert(mbuf);
                                nxlen = inlen + rte_pktmbuf_data_len(mbuf);
                        } while (unlikely(nxlen < txq->inlen_send));
                }
                start = rte_pktmbuf_mtod(mbuf, uintptr_t);
                /*
                 * Check whether we can do inline to align start
                 * address of data buffer to cacheline.
                 */
do_align:
                start = (~start + 1) & (RTE_CACHE_LINE_SIZE - 1);
                if (unlikely(start)) {
                        start += inlen;
                        if (start <= txq->inlen_send)
                                inlen = start;
                }
        }
        /*
         * Check whether there are enough free WQEBBs:
         * - Control Segment
         * - Ethernet Segment
         * - First Segment of inlined Ethernet data
         * - ... data continued ...
         * - Data Segments of pointer/min inline type
         *
         * Estimate the number of Data Segments conservatively,
         * supposing no any mbufs is being freed during inlining.
         */
        assert(inlen <= txq->inlen_send);
        ds = NB_SEGS(loc->mbuf) + 2 + (inlen -
                                       MLX5_ESEG_MIN_INLINE_SIZE +
                                       MLX5_WSEG_SIZE +
                                       MLX5_WSEG_SIZE - 1) / MLX5_WSEG_SIZE;
        if (unlikely(loc->wqe_free < ((ds + 3) / 4)))
                return MLX5_TXCMP_CODE_EXIT;
        /* Check for maximal WQE size. */
        if (unlikely((MLX5_WQE_SIZE_MAX / MLX5_WSEG_SIZE) < ((ds + 3) / 4)))
                return MLX5_TXCMP_CODE_ERROR;
#ifdef MLX5_PMD_SOFT_COUNTERS
        /* Update sent data bytes/packets counters. */
        txq->stats.obytes += dlen + vlan;
#endif
        wqe = txq->wqes + (txq->wqe_ci & txq->wqe_m);
        loc->wqe_last = wqe;
        mlx5_tx_cseg_init(txq, loc, wqe, 0, MLX5_OPCODE_SEND, olx);
        ds = mlx5_tx_mseg_build(txq, loc, wqe, vlan, inlen, 0, olx);
        wqe->cseg.sq_ds = rte_cpu_to_be_32(txq->qp_num_8s | ds);
        txq->wqe_ci += (ds + 3) / 4;
        loc->wqe_free -= (ds + 3) / 4;
        /* Request CQE generation if limits are reached. */
        mlx5_tx_request_completion(txq, loc, true, olx);
        return MLX5_TXCMP_CODE_MULTI;
}

/**
 * Tx burst function for multi-segment packets. Supports all
 * types of Tx offloads, uses MLX5_OPCODE_SEND/TSO to build WQEs,
 * sends one packet per WQE. Function stops sending if it
 * encounters the single-segment packet.
 *
 * This routine is responsible for storing processed mbuf
 * into elts ring buffer and update elts_head.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param[in] pkts
 *   Packets to transmit.
 * @param pkts_n
 *   Number of packets in array.
 * @param loc
 *   Pointer to burst routine local context.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 *
 * @return
 *   MLX5_TXCMP_CODE_EXIT - sending is done or impossible.
 *   MLX5_TXCMP_CODE_ERROR - some unrecoverable error occurred.
 *   MLX5_TXCMP_CODE_SINGLE - single-segment packet encountered.
 *   MLX5_TXCMP_CODE_TSO - TSO single-segment packet encountered.
 * Local context variables updated.
 */
static __rte_always_inline enum mlx5_txcmp_code
mlx5_tx_burst_mseg(struct mlx5_txq_data *restrict txq,
                   struct rte_mbuf **restrict pkts,
                   unsigned int pkts_n,
                   struct mlx5_txq_local *restrict loc,
                   unsigned int olx)
{
        assert(loc->elts_free && loc->wqe_free);
        assert(pkts_n > loc->pkts_sent);
        pkts += loc->pkts_sent + 1;
        pkts_n -= loc->pkts_sent;
        for (;;) {
                enum mlx5_txcmp_code ret;

                assert(NB_SEGS(loc->mbuf) > 1);
                /*
                 * Estimate the number of free elts quickly but
                 * conservatively. Some segment may be fully inlined
                 * and freed, ignore this here - precise estimation
                 * is costly.
                 */
                if (loc->elts_free < NB_SEGS(loc->mbuf))
                        return MLX5_TXCMP_CODE_EXIT;
                if (MLX5_TXOFF_CONFIG(TSO) &&
                    unlikely(loc->mbuf->ol_flags & PKT_TX_TCP_SEG)) {
                        /* Proceed with multi-segment TSO. */
                        ret = mlx5_tx_packet_multi_tso(txq, loc, olx);
                } else if (MLX5_TXOFF_CONFIG(INLINE)) {
                        /* Proceed with multi-segment SEND with inlining. */
                        ret = mlx5_tx_packet_multi_inline(txq, loc, olx);
                } else {
                        /* Proceed with multi-segment SEND w/o inlining. */
                        ret = mlx5_tx_packet_multi_send(txq, loc, olx);
                }
                if (ret == MLX5_TXCMP_CODE_EXIT)
                        return MLX5_TXCMP_CODE_EXIT;
                if (ret == MLX5_TXCMP_CODE_ERROR)
                        return MLX5_TXCMP_CODE_ERROR;
                /* WQE is built, go to the next packet. */
                ++loc->pkts_sent;
                --pkts_n;
                if (unlikely(!pkts_n || !loc->elts_free || !loc->wqe_free))
                        return MLX5_TXCMP_CODE_EXIT;
                loc->mbuf = *pkts++;
                if (pkts_n > 1)
                        rte_prefetch0(*pkts);
                if (likely(NB_SEGS(loc->mbuf) > 1))
                        continue;
                /* Here ends the series of multi-segment packets. */
                if (MLX5_TXOFF_CONFIG(TSO) &&
                    unlikely(loc->mbuf->ol_flags & PKT_TX_TCP_SEG))
                        return MLX5_TXCMP_CODE_TSO;
                return MLX5_TXCMP_CODE_SINGLE;
        }
        assert(false);
}

/**
 * Tx burst function for single-segment packets with TSO.
 * Supports all types of Tx offloads, except multi-packets.
 * Uses MLX5_OPCODE_TSO to build WQEs, sends one packet per WQE.
 * Function stops sending if it encounters the multi-segment
 * packet or packet without TSO requested.
 *
 * The routine is responsible for storing processed mbuf
 * into elts ring buffer and update elts_head if inline
 * offloads is requested due to possible early freeing
 * of the inlined mbufs (can not store pkts array in elts
 * as a batch).
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param[in] pkts
 *   Packets to transmit.
 * @param pkts_n
 *   Number of packets in array.
 * @param loc
 *   Pointer to burst routine local context.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 *
 * @return
 *   MLX5_TXCMP_CODE_EXIT - sending is done or impossible.
 *   MLX5_TXCMP_CODE_ERROR - some unrecoverable error occurred.
 *   MLX5_TXCMP_CODE_SINGLE - single-segment packet encountered.
 *   MLX5_TXCMP_CODE_MULTI - multi-segment packet encountered.
 * Local context variables updated.
 */
static __rte_always_inline enum mlx5_txcmp_code
mlx5_tx_burst_tso(struct mlx5_txq_data *restrict txq,
                  struct rte_mbuf **restrict pkts,
                  unsigned int pkts_n,
                  struct mlx5_txq_local *restrict loc,
                  unsigned int olx)
{
        assert(loc->elts_free && loc->wqe_free);
        assert(pkts_n > loc->pkts_sent);
        pkts += loc->pkts_sent + 1;
        pkts_n -= loc->pkts_sent;
        for (;;) {
                struct mlx5_wqe_dseg *restrict dseg;
                struct mlx5_wqe *restrict wqe;
                unsigned int ds, dlen, hlen, ntcp, vlan = 0;
                uint8_t *dptr;

                assert(NB_SEGS(loc->mbuf) == 1);
                dlen = rte_pktmbuf_data_len(loc->mbuf);
                if (MLX5_TXOFF_CONFIG(VLAN) &&
                    loc->mbuf->ol_flags & PKT_TX_VLAN_PKT) {
                        vlan = sizeof(struct rte_vlan_hdr);
                }
                /*
                 * First calculate the WQE size to check
                 * whether we have enough space in ring buffer.
                 */
                hlen = loc->mbuf->l2_len + vlan +
                       loc->mbuf->l3_len + loc->mbuf->l4_len;
                if (unlikely((!hlen || !loc->mbuf->tso_segsz)))
                        return MLX5_TXCMP_CODE_ERROR;
                if (loc->mbuf->ol_flags & PKT_TX_TUNNEL_MASK)
                        hlen += loc->mbuf->outer_l2_len +
                                loc->mbuf->outer_l3_len;
                /* Segment must contain all TSO headers. */
                if (unlikely(hlen > MLX5_MAX_TSO_HEADER ||
                             hlen <= MLX5_ESEG_MIN_INLINE_SIZE ||
                             hlen > (dlen + vlan)))
                        return MLX5_TXCMP_CODE_ERROR;
                /*
                 * Check whether there are enough free WQEBBs:
                 * - Control Segment
                 * - Ethernet Segment
                 * - First Segment of inlined Ethernet data
                 * - ... data continued ...
                 * - Finishing Data Segment of pointer type
                 */
                ds = 4 + (hlen - MLX5_ESEG_MIN_INLINE_SIZE +
                          MLX5_WSEG_SIZE - 1) / MLX5_WSEG_SIZE;
                if (loc->wqe_free < ((ds + 3) / 4))
                        return MLX5_TXCMP_CODE_EXIT;
#ifdef MLX5_PMD_SOFT_COUNTERS
                /* Update sent data bytes/packets counters. */
                ntcp = (dlen + vlan - hlen +
                        loc->mbuf->tso_segsz - 1) /
                        loc->mbuf->tso_segsz;
                /*
                 * One will be added for mbuf itself at the end
                 * of the mlx5_tx_burst from loc->pkts_sent field.
                 */
                --ntcp;
                txq->stats.opackets += ntcp;
                txq->stats.obytes += dlen + vlan + ntcp * hlen;
#endif
                /*
                 * Build the TSO WQE:
                 * - Control Segment
                 * - Ethernet Segment with hlen bytes inlined
                 * - Data Segment of pointer type
                 */
                wqe = txq->wqes + (txq->wqe_ci & txq->wqe_m);
                loc->wqe_last = wqe;
                mlx5_tx_cseg_init(txq, loc, wqe, ds,
                                  MLX5_OPCODE_TSO, olx);
                dseg = mlx5_tx_eseg_data(txq, loc, wqe, vlan, hlen, 1, olx);
                dptr = rte_pktmbuf_mtod(loc->mbuf, uint8_t *) + hlen - vlan;
                dlen -= hlen - vlan;
                mlx5_tx_dseg_ptr(txq, loc, dseg, dptr, dlen, olx);
                /*
                 * WQE is built, update the loop parameters
                 * and go to the next packet.
                 */
                txq->wqe_ci += (ds + 3) / 4;
                loc->wqe_free -= (ds + 3) / 4;
                if (MLX5_TXOFF_CONFIG(INLINE))
                        txq->elts[txq->elts_head++ & txq->elts_m] = loc->mbuf;
                --loc->elts_free;
                ++loc->pkts_sent;
                --pkts_n;
                /* Request CQE generation if limits are reached. */
                mlx5_tx_request_completion(txq, loc, false, olx);
                if (unlikely(!pkts_n || !loc->elts_free || !loc->wqe_free))
                        return MLX5_TXCMP_CODE_EXIT;
                loc->mbuf = *pkts++;
                if (pkts_n > 1)
                        rte_prefetch0(*pkts);
                if (MLX5_TXOFF_CONFIG(MULTI) &&
                    unlikely(NB_SEGS(loc->mbuf) > 1))
                        return MLX5_TXCMP_CODE_MULTI;
                if (likely(!(loc->mbuf->ol_flags & PKT_TX_TCP_SEG)))
                        return MLX5_TXCMP_CODE_SINGLE;
                /* Continue with the next TSO packet. */
        }
        assert(false);
}

/**
 * Analyze the packet and select the best method to send.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 * @param newp
 *   The predefined flag whether do complete check for
 *   multi-segment packets and TSO.
 *
 * @return
 *  MLX5_TXCMP_CODE_MULTI - multi-segment packet encountered.
 *  MLX5_TXCMP_CODE_TSO - TSO required, use TSO/LSO.
 *  MLX5_TXCMP_CODE_SINGLE - single-segment packet, use SEND.
 *  MLX5_TXCMP_CODE_EMPW - single-segment packet, use MPW.
 */
static __rte_always_inline enum mlx5_txcmp_code
mlx5_tx_able_to_empw(struct mlx5_txq_data *restrict txq,
                     struct mlx5_txq_local *restrict loc,
                     unsigned int olx,
                     bool newp)
{
        /* Check for multi-segment packet. */
        if (newp &&
            MLX5_TXOFF_CONFIG(MULTI) &&
            unlikely(NB_SEGS(loc->mbuf) > 1))
                return MLX5_TXCMP_CODE_MULTI;
        /* Check for TSO packet. */
        if (newp &&
            MLX5_TXOFF_CONFIG(TSO) &&
            unlikely(loc->mbuf->ol_flags & PKT_TX_TCP_SEG))
                return MLX5_TXCMP_CODE_TSO;
        /* Check if eMPW is enabled at all. */
        if (!MLX5_TXOFF_CONFIG(EMPW))
                return MLX5_TXCMP_CODE_SINGLE;
        /* Check if eMPW can be engaged. */
        if (MLX5_TXOFF_CONFIG(VLAN) &&
            unlikely(loc->mbuf->ol_flags & PKT_TX_VLAN_PKT) &&
                (!MLX5_TXOFF_CONFIG(INLINE) ||
                 unlikely((rte_pktmbuf_data_len(loc->mbuf) +
                           sizeof(struct rte_vlan_hdr)) > txq->inlen_empw))) {
                /*
                 * eMPW does not support VLAN insertion offload,
                 * we have to inline the entire packet but
                 * packet is too long for inlining.
                 */
                return MLX5_TXCMP_CODE_SINGLE;
        }
        return MLX5_TXCMP_CODE_EMPW;
}

/**
 * Check the next packet attributes to match with the eMPW batch ones.
 * In addition, for legacy MPW the packet length is checked either.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param es
 *   Pointer to Ethernet Segment of eMPW batch.
 * @param loc
 *   Pointer to burst routine local context.
 * @param dlen
 *   Length of previous packet in MPW descriptor.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 *
 * @return
 *  true - packet match with eMPW batch attributes.
 *  false - no match, eMPW should be restarted.
 */
static __rte_always_inline bool
mlx5_tx_match_empw(struct mlx5_txq_data *restrict txq __rte_unused,
                   struct mlx5_wqe_eseg *restrict es,
                   struct mlx5_txq_local *restrict loc,
                   uint32_t dlen,
                   unsigned int olx)
{
        uint8_t swp_flags = 0;

        /* Compare the checksum flags, if any. */
        if (MLX5_TXOFF_CONFIG(CSUM) &&
            txq_ol_cksum_to_cs(loc->mbuf) != es->cs_flags)
                return false;
        /* Compare the Software Parser offsets and flags. */
        if (MLX5_TXOFF_CONFIG(SWP) &&
            (es->swp_offs != txq_mbuf_to_swp(loc, &swp_flags, olx) ||
             es->swp_flags != swp_flags))
                return false;
        /* Fill metadata field if needed. */
        if (MLX5_TXOFF_CONFIG(METADATA) &&
                es->metadata != (loc->mbuf->ol_flags & PKT_TX_DYNF_METADATA ?
                                 *RTE_FLOW_DYNF_METADATA(loc->mbuf) : 0))
                return false;
        /* Legacy MPW can send packets with the same lengt only. */
        if (MLX5_TXOFF_CONFIG(MPW) &&
            dlen != rte_pktmbuf_data_len(loc->mbuf))
                return false;
        /* There must be no VLAN packets in eMPW loop. */
        if (MLX5_TXOFF_CONFIG(VLAN))
                assert(!(loc->mbuf->ol_flags & PKT_TX_VLAN_PKT));
        return true;
}

/*
 * Update send loop variables and WQE for eMPW loop
 * without data inlining. Number of Data Segments is
 * equal to the number of sent packets.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param ds
 *   Number of packets/Data Segments/Packets.
 * @param slen
 *   Accumulated statistics, bytes sent
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 *
 * @return
 *  true - packet match with eMPW batch attributes.
 *  false - no match, eMPW should be restarted.
 */
static __rte_always_inline void
mlx5_tx_sdone_empw(struct mlx5_txq_data *restrict txq,
                   struct mlx5_txq_local *restrict loc,
                   unsigned int ds,
                   unsigned int slen,
                   unsigned int olx)
{
        assert(!MLX5_TXOFF_CONFIG(INLINE));
#ifdef MLX5_PMD_SOFT_COUNTERS
        /* Update sent data bytes counter. */
         txq->stats.obytes += slen;
#else
        (void)slen;
#endif
        loc->elts_free -= ds;
        loc->pkts_sent += ds;
        ds += 2;
        loc->wqe_last->cseg.sq_ds = rte_cpu_to_be_32(txq->qp_num_8s | ds);
        txq->wqe_ci += (ds + 3) / 4;
        loc->wqe_free -= (ds + 3) / 4;
        /* Request CQE generation if limits are reached. */
        mlx5_tx_request_completion(txq, loc, false, olx);
}

/*
 * Update send loop variables and WQE for eMPW loop
 * with data inlining. Gets the size of pushed descriptors
 * and data to the WQE.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param loc
 *   Pointer to burst routine local context.
 * @param len
 *   Total size of descriptor/data in bytes.
 * @param slen
 *   Accumulated statistics, data bytes sent.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 *
 * @return
 *  true - packet match with eMPW batch attributes.
 *  false - no match, eMPW should be restarted.
 */
static __rte_always_inline void
mlx5_tx_idone_empw(struct mlx5_txq_data *restrict txq,
                   struct mlx5_txq_local *restrict loc,
                   unsigned int len,
                   unsigned int slen,
                   unsigned int olx __rte_unused)
{
        assert(MLX5_TXOFF_CONFIG(INLINE));
        assert((len % MLX5_WSEG_SIZE) == 0);
#ifdef MLX5_PMD_SOFT_COUNTERS
        /* Update sent data bytes counter. */
         txq->stats.obytes += slen;
#else
        (void)slen;
#endif
        len = len / MLX5_WSEG_SIZE + 2;
        loc->wqe_last->cseg.sq_ds = rte_cpu_to_be_32(txq->qp_num_8s | len);
        txq->wqe_ci += (len + 3) / 4;
        loc->wqe_free -= (len + 3) / 4;
        /* Request CQE generation if limits are reached. */
        mlx5_tx_request_completion(txq, loc, false, olx);
}

/**
 * The set of Tx burst functions for single-segment packets
 * without TSO and with Multi-Packet Writing feature support.
 * Supports all types of Tx offloads, except multi-packets
 * and TSO.
 *
 * Uses MLX5_OPCODE_EMPW to build WQEs if possible and sends
 * as many packet per WQE as it can. If eMPW is not configured
 * or packet can not be sent with eMPW (VLAN insertion) the
 * ordinary SEND opcode is used and only one packet placed
 * in WQE.
 *
 * Functions stop sending if it encounters the multi-segment
 * packet or packet with TSO requested.
 *
 * The routines are responsible for storing processed mbuf
 * into elts ring buffer and update elts_head if inlining
 * offload is requested. Otherwise the copying mbufs to elts
 * can be postponed and completed at the end of burst routine.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param[in] pkts
 *   Packets to transmit.
 * @param pkts_n
 *   Number of packets in array.
 * @param loc
 *   Pointer to burst routine local context.
 * @param olx
 *   Configured Tx offloads mask. It is fully defined at
 *   compile time and may be used for optimization.
 *
 * @return
 *   MLX5_TXCMP_CODE_EXIT - sending is done or impossible.
 *   MLX5_TXCMP_CODE_ERROR - some unrecoverable error occurred.
 *   MLX5_TXCMP_CODE_MULTI - multi-segment packet encountered.
 *   MLX5_TXCMP_CODE_TSO - TSO packet encountered.
 *   MLX5_TXCMP_CODE_SINGLE - used inside functions set.
 *   MLX5_TXCMP_CODE_EMPW - used inside functions set.
 *
 * Local context variables updated.
 *
 *
 * The routine sends packets with MLX5_OPCODE_EMPW
 * without inlining, this is dedicated optimized branch.
 * No VLAN insertion is supported.
 */
static __rte_always_inline enum mlx5_txcmp_code
mlx5_tx_burst_empw_simple(struct mlx5_txq_data *restrict txq,
                          struct rte_mbuf **restrict pkts,
                          unsigned int pkts_n,
                          struct mlx5_txq_local *restrict loc,
                          unsigned int olx)
{
        /*
         * Subroutine is the part of mlx5_tx_burst_single()
         * and sends single-segment packet with eMPW opcode
         * without data inlining.
         */
        assert(!MLX5_TXOFF_CONFIG(INLINE));
        assert(MLX5_TXOFF_CONFIG(EMPW));
        assert(loc->elts_free && loc->wqe_free);
        assert(pkts_n > loc->pkts_sent);
        static_assert(MLX5_EMPW_MIN_PACKETS >= 2, "invalid min size");
        pkts += loc->pkts_sent + 1;
        pkts_n -= loc->pkts_sent;
        for (;;) {
                struct mlx5_wqe_dseg *restrict dseg;
                struct mlx5_wqe_eseg *restrict eseg;
                enum mlx5_txcmp_code ret;
                unsigned int part, loop;
                unsigned int slen = 0;

next_empw:
                assert(NB_SEGS(loc->mbuf) == 1);
                part = RTE_MIN(pkts_n, MLX5_TXOFF_CONFIG(MPW) ?
                                       MLX5_MPW_MAX_PACKETS :
                                       MLX5_EMPW_MAX_PACKETS);
                if (unlikely(loc->elts_free < part)) {
                        /* We have no enough elts to save all mbufs. */
                        if (unlikely(loc->elts_free < MLX5_EMPW_MIN_PACKETS))
                                return MLX5_TXCMP_CODE_EXIT;
                        /* But we still able to send at least minimal eMPW. */
                        part = loc->elts_free;
                }
                /* Check whether we have enough WQEs */
                if (unlikely(loc->wqe_free < ((2 + part + 3) / 4))) {
                        if (unlikely(loc->wqe_free <
                                ((2 + MLX5_EMPW_MIN_PACKETS + 3) / 4)))
                                return MLX5_TXCMP_CODE_EXIT;
                        part = (loc->wqe_free * 4) - 2;
                }
                if (likely(part > 1))
                        rte_prefetch0(*pkts);
                loc->wqe_last = txq->wqes + (txq->wqe_ci & txq->wqe_m);
                /*
                 * Build eMPW title WQEBB:
                 * - Control Segment, eMPW opcode
                 * - Ethernet Segment, no inline
                 */
                mlx5_tx_cseg_init(txq, loc, loc->wqe_last, part + 2,
                                  MLX5_OPCODE_ENHANCED_MPSW, olx);
                mlx5_tx_eseg_none(txq, loc, loc->wqe_last,
                                  olx & ~MLX5_TXOFF_CONFIG_VLAN);
                eseg = &loc->wqe_last->eseg;
                dseg = &loc->wqe_last->dseg[0];
                loop = part;
                /* Store the packet length for legacy MPW. */
                if (MLX5_TXOFF_CONFIG(MPW))
                        eseg->mss = rte_cpu_to_be_16
                                        (rte_pktmbuf_data_len(loc->mbuf));
                for (;;) {
                        uint32_t dlen = rte_pktmbuf_data_len(loc->mbuf);
#ifdef MLX5_PMD_SOFT_COUNTERS
                        /* Update sent data bytes counter. */
                        slen += dlen;
#endif
                        mlx5_tx_dseg_ptr
                                (txq, loc, dseg,
                                 rte_pktmbuf_mtod(loc->mbuf, uint8_t *),
                                 dlen, olx);
                        if (unlikely(--loop == 0))
                                break;
                        loc->mbuf = *pkts++;
                        if (likely(loop > 1))
                                rte_prefetch0(*pkts);
                        ret = mlx5_tx_able_to_empw(txq, loc, olx, true);
                        /*
                         * Unroll the completion code to avoid
                         * returning variable value - it results in
                         * unoptimized sequent checking in caller.
                         */
                        if (ret == MLX5_TXCMP_CODE_MULTI) {
                                part -= loop;
                                mlx5_tx_sdone_empw(txq, loc, part, slen, olx);
                                if (unlikely(!loc->elts_free ||
                                             !loc->wqe_free))
                                        return MLX5_TXCMP_CODE_EXIT;
                                return MLX5_TXCMP_CODE_MULTI;
                        }
                        assert(NB_SEGS(loc->mbuf) == 1);
                        if (ret == MLX5_TXCMP_CODE_TSO) {
                                part -= loop;
                                mlx5_tx_sdone_empw(txq, loc, part, slen, olx);
                                if (unlikely(!loc->elts_free ||
                                             !loc->wqe_free))
                                        return MLX5_TXCMP_CODE_EXIT;
                                return MLX5_TXCMP_CODE_TSO;
                        }
                        if (ret == MLX5_TXCMP_CODE_SINGLE) {
                                part -= loop;
                                mlx5_tx_sdone_empw(txq, loc, part, slen, olx);
                                if (unlikely(!loc->elts_free ||
                                             !loc->wqe_free))
                                        return MLX5_TXCMP_CODE_EXIT;
                                return MLX5_TXCMP_CODE_SINGLE;
                        }
                        if (ret != MLX5_TXCMP_CODE_EMPW) {
                                assert(false);
                                part -= loop;
                                mlx5_tx_sdone_empw(txq, loc, part, slen, olx);
                                return MLX5_TXCMP_CODE_ERROR;
                        }
                        /*
                         * Check whether packet parameters coincide
                         * within assumed eMPW batch:
                         * - check sum settings
                         * - metadata value
                         * - software parser settings
                         * - packets length (legacy MPW only)
                         */
                        if (!mlx5_tx_match_empw(txq, eseg, loc, dlen, olx)) {
                                assert(loop);
                                part -= loop;
                                mlx5_tx_sdone_empw(txq, loc, part, slen, olx);
                                if (unlikely(!loc->elts_free ||
                                             !loc->wqe_free))
                                        return MLX5_TXCMP_CODE_EXIT;
                                pkts_n -= part;
                                goto next_empw;
                        }
                        /* Packet attributes match, continue the same eMPW. */
                        ++dseg;
                        if ((uintptr_t)dseg >= (uintptr_t)txq->wqes_end)
                                dseg = (struct mlx5_wqe_dseg *)txq->wqes;
                }
                /* eMPW is built successfully, update loop parameters. */
                assert(!loop);
                assert(pkts_n >= part);
#ifdef MLX5_PMD_SOFT_COUNTERS
                /* Update sent data bytes counter. */
                txq->stats.obytes += slen;
#endif
                loc->elts_free -= part;
                loc->pkts_sent += part;
                txq->wqe_ci += (2 + part + 3) / 4;
                loc->wqe_free -= (2 + part + 3) / 4;
                pkts_n -= part;
                /* Request CQE generation if limits are reached. */
                mlx5_tx_request_completion(txq, loc, false, olx);
                if (unlikely(!pkts_n || !loc->elts_free || !loc->wqe_free))
                        return MLX5_TXCMP_CODE_EXIT;
                loc->mbuf = *pkts++;
                ret = mlx5_tx_able_to_empw(txq, loc, olx, true);
                if (unlikely(ret != MLX5_TXCMP_CODE_EMPW))
                        return ret;
                /* Continue sending eMPW batches. */
        }
        assert(false);
}

/**
 * The routine sends packets with MLX5_OPCODE_EMPW
 * with inlining, optionally supports VLAN insertion.
 */
static __rte_always_inline enum mlx5_txcmp_code
mlx5_tx_burst_empw_inline(struct mlx5_txq_data *restrict txq,
                          struct rte_mbuf **restrict pkts,
                          unsigned int pkts_n,
                          struct mlx5_txq_local *restrict loc,
                          unsigned int olx)
{
        /*
         * Subroutine is the part of mlx5_tx_burst_single()
         * and sends single-segment packet with eMPW opcode
         * with data inlining.
         */
        assert(MLX5_TXOFF_CONFIG(INLINE));
        assert(MLX5_TXOFF_CONFIG(EMPW));
        assert(loc->elts_free && loc->wqe_free);
        assert(pkts_n > loc->pkts_sent);
        static_assert(MLX5_EMPW_MIN_PACKETS >= 2, "invalid min size");
        pkts += loc->pkts_sent + 1;
        pkts_n -= loc->pkts_sent;
        for (;;) {
                struct mlx5_wqe_dseg *restrict dseg;
                struct mlx5_wqe_eseg *restrict eseg;
                enum mlx5_txcmp_code ret;
                unsigned int room, part, nlim;
                unsigned int slen = 0;

                assert(NB_SEGS(loc->mbuf) == 1);
                /*
                 * Limits the amount of packets in one WQE
                 * to improve CQE latency generation.
                 */
                nlim = RTE_MIN(pkts_n, MLX5_EMPW_MAX_PACKETS);
                /* Check whether we have minimal amount WQEs */
                if (unlikely(loc->wqe_free <
                            ((2 + MLX5_EMPW_MIN_PACKETS + 3) / 4)))
                        return MLX5_TXCMP_CODE_EXIT;
                if (likely(pkts_n > 1))
                        rte_prefetch0(*pkts);
                loc->wqe_last = txq->wqes + (txq->wqe_ci & txq->wqe_m);
                /*
                 * Build eMPW title WQEBB:
                 * - Control Segment, eMPW opcode, zero DS
                 * - Ethernet Segment, no inline
                 */
                mlx5_tx_cseg_init(txq, loc, loc->wqe_last, 0,
                                  MLX5_OPCODE_ENHANCED_MPSW, olx);
                mlx5_tx_eseg_none(txq, loc, loc->wqe_last,
                                  olx & ~MLX5_TXOFF_CONFIG_VLAN);
                eseg = &loc->wqe_last->eseg;
                dseg = &loc->wqe_last->dseg[0];
                /* Store the packet length for legacy MPW. */
                if (MLX5_TXOFF_CONFIG(MPW))
                        eseg->mss = rte_cpu_to_be_16
                                        (rte_pktmbuf_data_len(loc->mbuf));
                room = RTE_MIN(MLX5_WQE_SIZE_MAX / MLX5_WQE_SIZE,
                               loc->wqe_free) * MLX5_WQE_SIZE -
                                        MLX5_WQE_CSEG_SIZE -
                                        MLX5_WQE_ESEG_SIZE;
                /* Build WQE till we have space, packets and resources. */
                part = room;
                for (;;) {
                        uint32_t dlen = rte_pktmbuf_data_len(loc->mbuf);
                        uint8_t *dptr = rte_pktmbuf_mtod(loc->mbuf, uint8_t *);
                        unsigned int tlen;

                        assert(room >= MLX5_WQE_DSEG_SIZE);
                        assert((room % MLX5_WQE_DSEG_SIZE) == 0);
                        assert((uintptr_t)dseg < (uintptr_t)txq->wqes_end);
                        /*
                         * Some Tx offloads may cause an error if
                         * packet is not long enough, check against
                         * assumed minimal length.
                         */
                        if (unlikely(dlen <= MLX5_ESEG_MIN_INLINE_SIZE)) {
                                part -= room;
                                if (unlikely(!part))
                                        return MLX5_TXCMP_CODE_ERROR;
                                /*
                                 * We have some successfully built
                                 * packet Data Segments to send.
                                 */
                                mlx5_tx_idone_empw(txq, loc, part, slen, olx);
                                return MLX5_TXCMP_CODE_ERROR;
                        }
                        /* Inline or not inline - that's the Question. */
                        if (dlen > txq->inlen_empw)
                                goto pointer_empw;
                        /* Inline entire packet, optional VLAN insertion. */
                        tlen = sizeof(dseg->bcount) + dlen;
                        if (MLX5_TXOFF_CONFIG(VLAN) &&
                            loc->mbuf->ol_flags & PKT_TX_VLAN_PKT) {
                                /*
                                 * The packet length must be checked in
                                 * mlx5_tx_able_to_empw() and packet
                                 * fits into inline length guaranteed.
                                 */
                                assert((dlen + sizeof(struct rte_vlan_hdr)) <=
                                        txq->inlen_empw);
                                tlen += sizeof(struct rte_vlan_hdr);
                                if (room < tlen)
                                        break;
                                dseg = mlx5_tx_dseg_vlan(txq, loc, dseg,
                                                         dptr, dlen, olx);
#ifdef MLX5_PMD_SOFT_COUNTERS
                                /* Update sent data bytes counter. */
                                slen += sizeof(struct rte_vlan_hdr);
#endif
                        } else {
                                if (room < tlen)
                                        break;
                                dseg = mlx5_tx_dseg_empw(txq, loc, dseg,
                                                         dptr, dlen, olx);
                        }
                        tlen = RTE_ALIGN(tlen, MLX5_WSEG_SIZE);
                        assert(room >= tlen);
                        room -= tlen;
                        /*
                         * Packet data are completely inlined,
                         * free the packet immediately.
                         */
                        rte_pktmbuf_free_seg(loc->mbuf);
                        goto next_mbuf;
pointer_empw:
                        /*
                         * Not inlinable VLAN packets are
                         * proceeded outside of this routine.
                         */
                        assert(room >= MLX5_WQE_DSEG_SIZE);
                        if (MLX5_TXOFF_CONFIG(VLAN))
                                assert(!(loc->mbuf->ol_flags &
                                         PKT_TX_VLAN_PKT));
                        mlx5_tx_dseg_ptr(txq, loc, dseg, dptr, dlen, olx);
                        /* We have to store mbuf in elts.*/
                        txq->elts[txq->elts_head++ & txq->elts_m] = loc->mbuf;
                        room -= MLX5_WQE_DSEG_SIZE;
                        /* Ring buffer wraparound is checked at the loop end.*/
                        ++dseg;
next_mbuf:
#ifdef MLX5_PMD_SOFT_COUNTERS
                        /* Update sent data bytes counter. */
                        slen += dlen;
#endif
                        loc->pkts_sent++;
                        loc->elts_free--;
                        pkts_n--;
                        if (unlikely(!pkts_n || !loc->elts_free)) {
                                /*
                                 * We have no resources/packets to
                                 * continue build descriptors.
                                 */
                                part -= room;
                                mlx5_tx_idone_empw(txq, loc, part, slen, olx);
                                return MLX5_TXCMP_CODE_EXIT;
                        }
                        loc->mbuf = *pkts++;
                        if (likely(pkts_n > 1))
                                rte_prefetch0(*pkts);
                        ret = mlx5_tx_able_to_empw(txq, loc, olx, true);
                        /*
                         * Unroll the completion code to avoid
                         * returning variable value - it results in
                         * unoptimized sequent checking in caller.
                         */
                        if (ret == MLX5_TXCMP_CODE_MULTI) {
                                part -= room;
                                mlx5_tx_idone_empw(txq, loc, part, slen, olx);
                                if (unlikely(!loc->elts_free ||
                                             !loc->wqe_free))
                                        return MLX5_TXCMP_CODE_EXIT;
                                return MLX5_TXCMP_CODE_MULTI;
                        }
                        assert(NB_SEGS(loc->mbuf) == 1);
                        if (ret == MLX5_TXCMP_CODE_TSO) {
                                part -= room;
                                mlx5_tx_idone_empw(txq, loc, part, slen, olx);
                                if (unlikely(!loc->elts_free ||
                                             !loc->wqe_free))
                                        return MLX5_TXCMP_CODE_EXIT;
                                return MLX5_TXCMP_CODE_TSO;
                        }
                        if (ret == MLX5_TXCMP_CODE_SINGLE) {
                                part -= room;
                                mlx5_tx_idone_empw(txq, loc, part, slen, olx);
                                if (unlikely(!loc->elts_free ||
                                             !loc->wqe_free))
                                        return MLX5_TXCMP_CODE_EXIT;
                                return MLX5_TXCMP_CODE_SINGLE;
                        }
                        if (ret != MLX5_TXCMP_CODE_EMPW) {
                                assert(false);
                                part -= room;
                                mlx5_tx_idone_empw(txq, loc, part, slen, olx);
                                return MLX5_TXCMP_CODE_ERROR;
                        }
                        /* Check if we have minimal room left. */
                        nlim--;
                        if (unlikely(!nlim || room < MLX5_WQE_DSEG_SIZE))
                                break;
                        /*
                         * Check whether packet parameters coincide
                         * within assumed eMPW batch:
                         * - check sum settings
                         * - metadata value
                         * - software parser settings
                         * - packets length (legacy MPW only)
                         */
                        if (!mlx5_tx_match_empw(txq, eseg, loc, dlen, olx))
                                break;
                        /* Packet attributes match, continue the same eMPW. */
                        if ((uintptr_t)dseg >= (uintptr_t)txq->wqes_end)
                                dseg = (struct mlx5_wqe_dseg *)txq->wqes;
                }
                /*
                 * We get here to close an existing eMPW
                 * session and start the new one.
                 */
                assert(pkts_n);
                part -= room;
                if (unlikely(!part))
                        return MLX5_TXCMP_CODE_EXIT;
                mlx5_tx_idone_empw(txq, loc, part, slen, olx);
                if (unlikely(!loc->elts_free ||
                             !loc->wqe_free))
                        return MLX5_TXCMP_CODE_EXIT;
                /* Continue the loop with new eMPW session. */
        }
        assert(false);
}

/**
 * The routine sends packets with ordinary MLX5_OPCODE_SEND.
 * Data inlining and VLAN insertion are supported.
 */
static __rte_always_inline enum mlx5_txcmp_code
mlx5_tx_burst_single_send(struct mlx5_txq_data *restrict txq,
                          struct rte_mbuf **restrict pkts,
                          unsigned int pkts_n,
                          struct mlx5_txq_local *restrict loc,
                          unsigned int olx)
{
        /*
         * Subroutine is the part of mlx5_tx_burst_single()
         * and sends single-segment packet with SEND opcode.
         */
        assert(loc->elts_free && loc->wqe_free);
        assert(pkts_n > loc->pkts_sent);
        pkts += loc->pkts_sent + 1;
        pkts_n -= loc->pkts_sent;
        for (;;) {
                struct mlx5_wqe *restrict wqe;
                enum mlx5_txcmp_code ret;

                assert(NB_SEGS(loc->mbuf) == 1);
                if (MLX5_TXOFF_CONFIG(INLINE)) {
                        unsigned int inlen, vlan = 0;

                        inlen = rte_pktmbuf_data_len(loc->mbuf);
                        if (MLX5_TXOFF_CONFIG(VLAN) &&
                            loc->mbuf->ol_flags & PKT_TX_VLAN_PKT) {
                                vlan = sizeof(struct rte_vlan_hdr);
                                inlen += vlan;
                                static_assert((sizeof(struct rte_vlan_hdr) +
                                               sizeof(struct rte_ether_hdr)) ==
                                               MLX5_ESEG_MIN_INLINE_SIZE,
                                               "invalid min inline data size");
                        }
                        /*
                         * If inlining is enabled at configuration time
                         * the limit must be not less than minimal size.
                         * Otherwise we would do extra check for data
                         * size to avoid crashes due to length overflow.
                         */
                        assert(txq->inlen_send >= MLX5_ESEG_MIN_INLINE_SIZE);
                        if (inlen <= txq->inlen_send) {
                                unsigned int seg_n, wqe_n;

                                rte_prefetch0(rte_pktmbuf_mtod
                                                (loc->mbuf, uint8_t *));
                                /* Check against minimal length. */
                                if (inlen <= MLX5_ESEG_MIN_INLINE_SIZE)
                                        return MLX5_TXCMP_CODE_ERROR;
                                /*
                                 * Completely inlined packet data WQE:
                                 * - Control Segment, SEND opcode
                                 * - Ethernet Segment, no VLAN insertion
                                 * - Data inlined, VLAN optionally inserted
                                 * - Alignment to MLX5_WSEG_SIZE
                                 * Have to estimate amount of WQEBBs
                                 */
                                seg_n = (inlen + 3 * MLX5_WSEG_SIZE -
                                         MLX5_ESEG_MIN_INLINE_SIZE +
                                         MLX5_WSEG_SIZE - 1) / MLX5_WSEG_SIZE;
                                /* Check if there are enough WQEBBs. */
                                wqe_n = (seg_n + 3) / 4;
                                if (wqe_n > loc->wqe_free)
                                        return MLX5_TXCMP_CODE_EXIT;
                                wqe = txq->wqes + (txq->wqe_ci & txq->wqe_m);
                                loc->wqe_last = wqe;
                                mlx5_tx_cseg_init(txq, loc, wqe, seg_n,
                                                  MLX5_OPCODE_SEND, olx);
                                mlx5_tx_eseg_data(txq, loc, wqe,
                                                  vlan, inlen, 0, olx);
                                txq->wqe_ci += wqe_n;
                                loc->wqe_free -= wqe_n;
                                /*
                                 * Packet data are completely inlined,
                                 * free the packet immediately.
                                 */
                                rte_pktmbuf_free_seg(loc->mbuf);
                        } else if ((!MLX5_TXOFF_CONFIG(EMPW) ||
                                     MLX5_TXOFF_CONFIG(MPW)) &&
                                        txq->inlen_mode) {
                                /*
                                 * If minimal inlining is requested the eMPW
                                 * feature should be disabled due to data is
                                 * inlined into Ethernet Segment, which can
                                 * not contain inlined data for eMPW due to
                                 * segment shared for all packets.
                                 */
                                struct mlx5_wqe_dseg *restrict dseg;
                                unsigned int ds;
                                uint8_t *dptr;

                                /*
                                 * The inline-mode settings require
                                 * to inline the specified amount of
                                 * data bytes to the Ethernet Segment.
                                 * We should check the free space in
                                 * WQE ring buffer to inline partially.
                                 */
                                assert(txq->inlen_send >= txq->inlen_mode);
                                assert(inlen > txq->inlen_mode);
                                assert(txq->inlen_mode >=
                                                MLX5_ESEG_MIN_INLINE_SIZE);
                                /*
                                 * Check whether there are enough free WQEBBs:
                                 * - Control Segment
                                 * - Ethernet Segment
                                 * - First Segment of inlined Ethernet data
                                 * - ... data continued ...
                                 * - Finishing Data Segment of pointer type
                                 */
                                ds = (MLX5_WQE_CSEG_SIZE +
                                      MLX5_WQE_ESEG_SIZE +
                                      MLX5_WQE_DSEG_SIZE +
                                      txq->inlen_mode -
                                      MLX5_ESEG_MIN_INLINE_SIZE +
                                      MLX5_WQE_DSEG_SIZE +
                                      MLX5_WSEG_SIZE - 1) / MLX5_WSEG_SIZE;
                                if (loc->wqe_free < ((ds + 3) / 4))
                                        return MLX5_TXCMP_CODE_EXIT;
                                /*
                                 * Build the ordinary SEND WQE:
                                 * - Control Segment
                                 * - Ethernet Segment, inline inlen_mode bytes
                                 * - Data Segment of pointer type
                                 */
                                wqe = txq->wqes + (txq->wqe_ci & txq->wqe_m);
                                loc->wqe_last = wqe;
                                mlx5_tx_cseg_init(txq, loc, wqe, ds,
                                                  MLX5_OPCODE_SEND, olx);
                                dseg = mlx5_tx_eseg_data(txq, loc, wqe, vlan,
                                                         txq->inlen_mode,
                                                         0, olx);
                                dptr = rte_pktmbuf_mtod(loc->mbuf, uint8_t *) +
                                       txq->inlen_mode - vlan;
                                inlen -= txq->inlen_mode;
                                mlx5_tx_dseg_ptr(txq, loc, dseg,
                                                 dptr, inlen, olx);
                                /*
                                 * WQE is built, update the loop parameters
                                 * and got to the next packet.
                                 */
                                txq->wqe_ci += (ds + 3) / 4;
                                loc->wqe_free -= (ds + 3) / 4;
                                /* We have to store mbuf in elts.*/
                                assert(MLX5_TXOFF_CONFIG(INLINE));
                                txq->elts[txq->elts_head++ & txq->elts_m] =
                                                loc->mbuf;
                                --loc->elts_free;
                        } else {
                                uint8_t *dptr;
                                unsigned int dlen;

                                /*
                                 * Partially inlined packet data WQE, we have
                                 * some space in title WQEBB, we can fill it
                                 * with some packet data. It takes one WQEBB,
                                 * it is available, no extra space check:
                                 * - Control Segment, SEND opcode
                                 * - Ethernet Segment, no VLAN insertion
                                 * - MLX5_ESEG_MIN_INLINE_SIZE bytes of Data
                                 * - Data Segment, pointer type
                                 *
                                 * We also get here if VLAN insertion is not
                                 * supported by HW, the inline is enabled.
                                 */
                                wqe = txq->wqes + (txq->wqe_ci & txq->wqe_m);
                                loc->wqe_last = wqe;
                                mlx5_tx_cseg_init(txq, loc, wqe, 4,
                                                  MLX5_OPCODE_SEND, olx);
                                mlx5_tx_eseg_dmin(txq, loc, wqe, vlan, olx);
                                dptr = rte_pktmbuf_mtod(loc->mbuf, uint8_t *) +
                                       MLX5_ESEG_MIN_INLINE_SIZE - vlan;
                                /*
                                 * The length check is performed above, by
                                 * comparing with txq->inlen_send. We should
                                 * not get overflow here.
                                 */
                                assert(inlen > MLX5_ESEG_MIN_INLINE_SIZE);
                                dlen = inlen - MLX5_ESEG_MIN_INLINE_SIZE;
                                mlx5_tx_dseg_ptr(txq, loc, &wqe->dseg[1],
                                                 dptr, dlen, olx);
                                ++txq->wqe_ci;
                                --loc->wqe_free;
                                /* We have to store mbuf in elts.*/
                                assert(MLX5_TXOFF_CONFIG(INLINE));
                                txq->elts[txq->elts_head++ & txq->elts_m] =
                                                loc->mbuf;
                                --loc->elts_free;
                        }
#ifdef MLX5_PMD_SOFT_COUNTERS
                        /* Update sent data bytes counter. */
                        txq->stats.obytes += vlan +
                                        rte_pktmbuf_data_len(loc->mbuf);
#endif
                } else {
                        /*
                         * No inline at all, it means the CPU cycles saving
                         * is prioritized at configuration, we should not
                         * copy any packet data to WQE.
                         *
                         * SEND WQE, one WQEBB:
                         * - Control Segment, SEND opcode
                         * - Ethernet Segment, optional VLAN, no inline
                         * - Data Segment, pointer type
                         */
                        wqe = txq->wqes + (txq->wqe_ci & txq->wqe_m);
                        loc->wqe_last = wqe;
                        mlx5_tx_cseg_init(txq, loc, wqe, 3,
                                          MLX5_OPCODE_SEND, olx);
                        mlx5_tx_eseg_none(txq, loc, wqe, olx);
                        mlx5_tx_dseg_ptr
                                (txq, loc, &wqe->dseg[0],
                                 rte_pktmbuf_mtod(loc->mbuf, uint8_t *),
                                 rte_pktmbuf_data_len(loc->mbuf), olx);
                        ++txq->wqe_ci;
                        --loc->wqe_free;
                        /*
                         * We should not store mbuf pointer in elts
                         * if no inlining is configured, this is done
                         * by calling routine in a batch copy.
                         */
                        assert(!MLX5_TXOFF_CONFIG(INLINE));
                        --loc->elts_free;
#ifdef MLX5_PMD_SOFT_COUNTERS
                        /* Update sent data bytes counter. */
                        txq->stats.obytes += rte_pktmbuf_data_len(loc->mbuf);
                        if (MLX5_TXOFF_CONFIG(VLAN) &&
                            loc->mbuf->ol_flags & PKT_TX_VLAN_PKT)
                                txq->stats.obytes +=
                                        sizeof(struct rte_vlan_hdr);
#endif
                }
                ++loc->pkts_sent;
                --pkts_n;
                /* Request CQE generation if limits are reached. */
                mlx5_tx_request_completion(txq, loc, false, olx);
                if (unlikely(!pkts_n || !loc->elts_free || !loc->wqe_free))
                        return MLX5_TXCMP_CODE_EXIT;
                loc->mbuf = *pkts++;
                if (pkts_n > 1)
                        rte_prefetch0(*pkts);
                ret = mlx5_tx_able_to_empw(txq, loc, olx, true);
                if (unlikely(ret != MLX5_TXCMP_CODE_SINGLE))
                        return ret;
        }
        assert(false);
}

static __rte_always_inline enum mlx5_txcmp_code
mlx5_tx_burst_single(struct mlx5_txq_data *restrict txq,
                     struct rte_mbuf **restrict pkts,
                     unsigned int pkts_n,
                     struct mlx5_txq_local *restrict loc,
                     unsigned int olx)
{
        enum mlx5_txcmp_code ret;

        ret = mlx5_tx_able_to_empw(txq, loc, olx, false);
        if (ret == MLX5_TXCMP_CODE_SINGLE)
                goto ordinary_send;
        assert(ret == MLX5_TXCMP_CODE_EMPW);
        for (;;) {
                /* Optimize for inline/no inline eMPW send. */
                ret = (MLX5_TXOFF_CONFIG(INLINE)) ?
                        mlx5_tx_burst_empw_inline
                                (txq, pkts, pkts_n, loc, olx) :
                        mlx5_tx_burst_empw_simple
                                (txq, pkts, pkts_n, loc, olx);
                if (ret != MLX5_TXCMP_CODE_SINGLE)
                        return ret;
                /* The resources to send one packet should remain. */
                assert(loc->elts_free && loc->wqe_free);
ordinary_send:
                ret = mlx5_tx_burst_single_send(txq, pkts, pkts_n, loc, olx);
                assert(ret != MLX5_TXCMP_CODE_SINGLE);
                if (ret != MLX5_TXCMP_CODE_EMPW)
                        return ret;
                /* The resources to send one packet should remain. */
                assert(loc->elts_free && loc->wqe_free);
        }
}

/**
 * DPDK Tx callback template. This is configured template
 * used to generate routines optimized for specified offload setup.
 * One of this generated functions is chosen at SQ configuration
 * time.
 *
 * @param txq
 *   Generic pointer to TX queue structure.
 * @param[in] pkts
 *   Packets to transmit.
 * @param pkts_n
 *   Number of packets in array.
 * @param olx
 *   Configured offloads mask, presents the bits of MLX5_TXOFF_CONFIG_xxx
 *   values. Should be static to take compile time static configuration
 *   advantages.
 *
 * @return
 *   Number of packets successfully transmitted (<= pkts_n).
 */
static __rte_always_inline uint16_t
mlx5_tx_burst_tmpl(struct mlx5_txq_data *restrict txq,
                   struct rte_mbuf **restrict pkts,
                   uint16_t pkts_n,
                   unsigned int olx)
{
        struct mlx5_txq_local loc;
        enum mlx5_txcmp_code ret;
        unsigned int part;

        assert(txq->elts_s >= (uint16_t)(txq->elts_head - txq->elts_tail));
        assert(txq->wqe_s >= (uint16_t)(txq->wqe_ci - txq->wqe_pi));
        if (unlikely(!pkts_n))
                return 0;
        loc.pkts_sent = 0;
        loc.pkts_copy = 0;
        loc.wqe_last = NULL;

send_loop:
        loc.pkts_loop = loc.pkts_sent;
        /*
         * Check if there are some CQEs, if any:
         * - process an encountered errors
         * - process the completed WQEs
         * - free related mbufs
         * - doorbell the NIC about processed CQEs
         */
        rte_prefetch0(*(pkts + loc.pkts_sent));
        mlx5_tx_handle_completion(txq, olx);
        /*
         * Calculate the number of available resources - elts and WQEs.
         * There are two possible different scenarios:
         * - no data inlining into WQEs, one WQEBB may contains upto
         *   four packets, in this case elts become scarce resource
         * - data inlining into WQEs, one packet may require multiple
         *   WQEBBs, the WQEs become the limiting factor.
         */
        assert(txq->elts_s >= (uint16_t)(txq->elts_head - txq->elts_tail));
        loc.elts_free = txq->elts_s -
                                (uint16_t)(txq->elts_head - txq->elts_tail);
        assert(txq->wqe_s >= (uint16_t)(txq->wqe_ci - txq->wqe_pi));
        loc.wqe_free = txq->wqe_s -
                                (uint16_t)(txq->wqe_ci - txq->wqe_pi);
        if (unlikely(!loc.elts_free || !loc.wqe_free))
                goto burst_exit;
        for (;;) {
                /*
                 * Fetch the packet from array. Usually this is
                 * the first packet in series of multi/single
                 * segment packets.
                 */
                loc.mbuf = *(pkts + loc.pkts_sent);
                /* Dedicated branch for multi-segment packets. */
                if (MLX5_TXOFF_CONFIG(MULTI) &&
                    unlikely(NB_SEGS(loc.mbuf) > 1)) {
                        /*
                         * Multi-segment packet encountered.
                         * Hardware is able to process it only
                         * with SEND/TSO opcodes, one packet
                         * per WQE, do it in dedicated routine.
                         */
enter_send_multi:
                        assert(loc.pkts_sent >= loc.pkts_copy);
                        part = loc.pkts_sent - loc.pkts_copy;
                        if (!MLX5_TXOFF_CONFIG(INLINE) && part) {
                                /*
                                 * There are some single-segment mbufs not
                                 * stored in elts. The mbufs must be in the
                                 * same order as WQEs, so we must copy the
                                 * mbufs to elts here, before the coming
                                 * multi-segment packet mbufs is appended.
                                 */
                                mlx5_tx_copy_elts(txq, pkts + loc.pkts_copy,
                                                  part, olx);
                                loc.pkts_copy = loc.pkts_sent;
                        }
                        assert(pkts_n > loc.pkts_sent);
                        ret = mlx5_tx_burst_mseg(txq, pkts, pkts_n, &loc, olx);
                        if (!MLX5_TXOFF_CONFIG(INLINE))
                                loc.pkts_copy = loc.pkts_sent;
                        /*
                         * These returned code checks are supposed
                         * to be optimized out due to routine inlining.
                         */
                        if (ret == MLX5_TXCMP_CODE_EXIT) {
                                /*
                                 * The routine returns this code when
                                 * all packets are sent or there is no
                                 * enough resources to complete request.
                                 */
                                break;
                        }
                        if (ret == MLX5_TXCMP_CODE_ERROR) {
                                /*
                                 * The routine returns this code when
                                 * some error in the incoming packets
                                 * format occurred.
                                 */
                                txq->stats.oerrors++;
                                break;
                        }
                        if (ret == MLX5_TXCMP_CODE_SINGLE) {
                                /*
                                 * The single-segment packet was encountered
                                 * in the array, try to send it with the
                                 * best optimized way, possible engaging eMPW.
                                 */
                                goto enter_send_single;
                        }
                        if (MLX5_TXOFF_CONFIG(TSO) &&
                            ret == MLX5_TXCMP_CODE_TSO) {
                                /*
                                 * The single-segment TSO packet was
                                 * encountered in the array.
                                 */
                                goto enter_send_tso;
                        }
                        /* We must not get here. Something is going wrong. */
                        assert(false);
                        txq->stats.oerrors++;
                        break;
                }
                /* Dedicated branch for single-segment TSO packets. */
                if (MLX5_TXOFF_CONFIG(TSO) &&
                    unlikely(loc.mbuf->ol_flags & PKT_TX_TCP_SEG)) {
                        /*
                         * TSO might require special way for inlining
                         * (dedicated parameters) and is sent with
                         * MLX5_OPCODE_TSO opcode only, provide this
                         * in dedicated branch.
                         */
enter_send_tso:
                        assert(NB_SEGS(loc.mbuf) == 1);
                        assert(pkts_n > loc.pkts_sent);
                        ret = mlx5_tx_burst_tso(txq, pkts, pkts_n, &loc, olx);
                        /*
                         * These returned code checks are supposed
                         * to be optimized out due to routine inlining.
                         */
                        if (ret == MLX5_TXCMP_CODE_EXIT)
                                break;
                        if (ret == MLX5_TXCMP_CODE_ERROR) {
                                txq->stats.oerrors++;
                                break;
                        }
                        if (ret == MLX5_TXCMP_CODE_SINGLE)
                                goto enter_send_single;
                        if (MLX5_TXOFF_CONFIG(MULTI) &&
                            ret == MLX5_TXCMP_CODE_MULTI) {
                                /*
                                 * The multi-segment packet was
                                 * encountered in the array.
                                 */
                                goto enter_send_multi;
                        }
                        /* We must not get here. Something is going wrong. */
                        assert(false);
                        txq->stats.oerrors++;
                        break;
                }
                /*
                 * The dedicated branch for the single-segment packets
                 * without TSO. Often these ones can be sent using
                 * MLX5_OPCODE_EMPW with multiple packets in one WQE.
                 * The routine builds the WQEs till it encounters
                 * the TSO or multi-segment packet (in case if these
                 * offloads are requested at SQ configuration time).
                 */
enter_send_single:
                assert(pkts_n > loc.pkts_sent);
                ret = mlx5_tx_burst_single(txq, pkts, pkts_n, &loc, olx);
                /*
                 * These returned code checks are supposed
                 * to be optimized out due to routine inlining.
                 */
                if (ret == MLX5_TXCMP_CODE_EXIT)
                        break;
                if (ret == MLX5_TXCMP_CODE_ERROR) {
                        txq->stats.oerrors++;
                        break;
                }
                if (MLX5_TXOFF_CONFIG(MULTI) &&
                    ret == MLX5_TXCMP_CODE_MULTI) {
                        /*
                         * The multi-segment packet was
                         * encountered in the array.
                         */
                        goto enter_send_multi;
                }
                if (MLX5_TXOFF_CONFIG(TSO) &&
                    ret == MLX5_TXCMP_CODE_TSO) {
                        /*
                         * The single-segment TSO packet was
                         * encountered in the array.
                         */
                        goto enter_send_tso;
                }
                /* We must not get here. Something is going wrong. */
                assert(false);
                txq->stats.oerrors++;
                break;
        }
        /*
         * Main Tx loop is completed, do the rest:
         * - set completion request if thresholds are reached
         * - doorbell the hardware
         * - copy the rest of mbufs to elts (if any)
         */
        assert(MLX5_TXOFF_CONFIG(INLINE) || loc.pkts_sent >= loc.pkts_copy);
        /* Take a shortcut if nothing is sent. */
        if (unlikely(loc.pkts_sent == loc.pkts_loop))
                goto burst_exit;
        /*
         * Ring QP doorbell immediately after WQE building completion
         * to improve latencies. The pure software related data treatment
         * can be completed after doorbell. Tx CQEs for this SQ are
         * processed in this thread only by the polling.
         *
         * The rdma core library can map doorbell register in two ways,
         * depending on the environment variable "MLX5_SHUT_UP_BF":
         *
         * - as regular cached memory, the variable is either missing or
         *   set to zero. This type of mapping may cause the significant
         *   doorbell register writing latency and requires explicit
         *   memory write barrier to mitigate this issue and prevent
         *   write combining.
         *
         * - as non-cached memory, the variable is present and set to
         *   not "0" value. This type of mapping may cause performance
         *   impact under heavy loading conditions but the explicit write
         *   memory barrier is not required and it may improve core
         *   performance.
         *
         * - the legacy behaviour (prior 19.08 release) was to use some
         *   heuristics to decide whether write memory barrier should
         *   be performed. This behavior is supported with specifying
         *   tx_db_nc=2, write barrier is skipped if application
         *   provides the full recommended burst of packets, it
         *   supposes the next packets are coming and the write barrier
         *   will be issued on the next burst (after descriptor writing,
         *   at least).
         */
        mlx5_tx_dbrec_cond_wmb(txq, loc.wqe_last, !txq->db_nc &&
                        (!txq->db_heu || pkts_n % MLX5_TX_DEFAULT_BURST));
        /* Not all of the mbufs may be stored into elts yet. */
        part = MLX5_TXOFF_CONFIG(INLINE) ? 0 : loc.pkts_sent - loc.pkts_copy;
        if (!MLX5_TXOFF_CONFIG(INLINE) && part) {
                /*
                 * There are some single-segment mbufs not stored in elts.
                 * It can be only if the last packet was single-segment.
                 * The copying is gathered into one place due to it is
                 * a good opportunity to optimize that with SIMD.
                 * Unfortunately if inlining is enabled the gaps in
                 * pointer array may happen due to early freeing of the
                 * inlined mbufs.
                 */
                mlx5_tx_copy_elts(txq, pkts + loc.pkts_copy, part, olx);
                loc.pkts_copy = loc.pkts_sent;
        }
        assert(txq->elts_s >= (uint16_t)(txq->elts_head - txq->elts_tail));
        assert(txq->wqe_s >= (uint16_t)(txq->wqe_ci - txq->wqe_pi));
        if (pkts_n > loc.pkts_sent) {
                /*
                 * If burst size is large there might be no enough CQE
                 * fetched from completion queue and no enough resources
                 * freed to send all the packets.
                 */
                goto send_loop;
        }
burst_exit:
#ifdef MLX5_PMD_SOFT_COUNTERS
        /* Increment sent packets counter. */
        txq->stats.opackets += loc.pkts_sent;
#endif
        return loc.pkts_sent;
}

/* Generate routines with Enhanced Multi-Packet Write support. */
MLX5_TXOFF_DECL(full_empw,
                MLX5_TXOFF_CONFIG_FULL | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_DECL(none_empw,
                MLX5_TXOFF_CONFIG_NONE | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_DECL(md_empw,
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_DECL(mt_empw,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_DECL(mtsc_empw,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_DECL(mti_empw,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_INLINE |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_DECL(mtv_empw,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_DECL(mtiv_empw,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_DECL(sc_empw,
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_DECL(sci_empw,
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_INLINE |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_DECL(scv_empw,
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_DECL(sciv_empw,
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_DECL(i_empw,
                MLX5_TXOFF_CONFIG_INLINE |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_DECL(v_empw,
                MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_DECL(iv_empw,
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

/* Generate routines without Enhanced Multi-Packet Write support. */
MLX5_TXOFF_DECL(full,
                MLX5_TXOFF_CONFIG_FULL)

MLX5_TXOFF_DECL(none,
                MLX5_TXOFF_CONFIG_NONE)

MLX5_TXOFF_DECL(md,
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_DECL(mt,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_DECL(mtsc,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_DECL(mti,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_INLINE |
                MLX5_TXOFF_CONFIG_METADATA)


MLX5_TXOFF_DECL(mtv,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA)


MLX5_TXOFF_DECL(mtiv,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_DECL(sc,
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_DECL(sci,
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_INLINE |
                MLX5_TXOFF_CONFIG_METADATA)


MLX5_TXOFF_DECL(scv,
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA)


MLX5_TXOFF_DECL(sciv,
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_DECL(i,
                MLX5_TXOFF_CONFIG_INLINE |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_DECL(v,
                MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_DECL(iv,
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA)

/*
 * Generate routines with Legacy Multi-Packet Write support.
 * This mode is supported by ConnectX-4LX only and imposes
 * offload limitations, not supported:
 *   - ACL/Flows (metadata are becoming meaningless)
 *   - WQE Inline headers
 *   - SRIOV (E-Switch offloads)
 *   - VLAN insertion
 *   - tunnel encapsulation/decapsulation
 *   - TSO
 */
MLX5_TXOFF_DECL(none_mpw,
                MLX5_TXOFF_CONFIG_NONE | MLX5_TXOFF_CONFIG_EMPW |
                MLX5_TXOFF_CONFIG_MPW)

MLX5_TXOFF_DECL(mci_mpw,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_EMPW |
                MLX5_TXOFF_CONFIG_MPW)

MLX5_TXOFF_DECL(i_mpw,
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_EMPW |
                MLX5_TXOFF_CONFIG_MPW)

/*
 * Array of declared and compiled Tx burst function and corresponding
 * supported offloads set. The array is used to select the Tx burst
 * function for specified offloads set at Tx queue configuration time.
 */
const struct {
        eth_tx_burst_t func;
        unsigned int olx;
} txoff_func[] = {
MLX5_TXOFF_INFO(full_empw,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_INFO(none_empw,
                MLX5_TXOFF_CONFIG_NONE | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_INFO(md_empw,
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_INFO(mt_empw,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_INFO(mtsc_empw,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_INFO(mti_empw,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_INLINE |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_INFO(mtv_empw,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_INFO(mtiv_empw,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_INFO(sc_empw,
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_INFO(sci_empw,
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_INLINE |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_INFO(scv_empw,
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_INFO(sciv_empw,
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_INFO(i_empw,
                MLX5_TXOFF_CONFIG_INLINE |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_INFO(v_empw,
                MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_INFO(iv_empw,
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA | MLX5_TXOFF_CONFIG_EMPW)

MLX5_TXOFF_INFO(full,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_INFO(none,
                MLX5_TXOFF_CONFIG_NONE)

MLX5_TXOFF_INFO(md,
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_INFO(mt,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_INFO(mtsc,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_INFO(mti,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_INLINE |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_INFO(mtv,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_INFO(mtiv,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_TSO |
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_INFO(sc,
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_INFO(sci,
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_INLINE |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_INFO(scv,
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_INFO(sciv,
                MLX5_TXOFF_CONFIG_SWP | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_INFO(i,
                MLX5_TXOFF_CONFIG_INLINE |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_INFO(v,
                MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_INFO(iv,
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_VLAN |
                MLX5_TXOFF_CONFIG_METADATA)

MLX5_TXOFF_INFO(none_mpw,
                MLX5_TXOFF_CONFIG_NONE | MLX5_TXOFF_CONFIG_EMPW |
                MLX5_TXOFF_CONFIG_MPW)

MLX5_TXOFF_INFO(mci_mpw,
                MLX5_TXOFF_CONFIG_MULTI | MLX5_TXOFF_CONFIG_CSUM |
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_EMPW |
                MLX5_TXOFF_CONFIG_MPW)

MLX5_TXOFF_INFO(i_mpw,
                MLX5_TXOFF_CONFIG_INLINE | MLX5_TXOFF_CONFIG_EMPW |
                MLX5_TXOFF_CONFIG_MPW)
};

/**
 * Configure the Tx function to use. The routine checks configured
 * Tx offloads for the device and selects appropriate Tx burst
 * routine. There are multiple Tx burst routines compiled from
 * the same template in the most optimal way for the dedicated
 * Tx offloads set.
 *
 * @param dev
 *   Pointer to private data structure.
 *
 * @return
 *   Pointer to selected Tx burst function.
 */
eth_tx_burst_t
mlx5_select_tx_function(struct rte_eth_dev *dev)
{
        struct mlx5_priv *priv = dev->data->dev_private;
        struct mlx5_dev_config *config = &priv->config;
        uint64_t tx_offloads = dev->data->dev_conf.txmode.offloads;
        unsigned int diff = 0, olx = 0, i, m;

        static_assert(MLX5_WQE_SIZE_MAX / MLX5_WSEG_SIZE <=
                      MLX5_DSEG_MAX, "invalid WQE max size");
        static_assert(MLX5_WQE_CSEG_SIZE == MLX5_WSEG_SIZE,
                      "invalid WQE Control Segment size");
        static_assert(MLX5_WQE_ESEG_SIZE == MLX5_WSEG_SIZE,
                      "invalid WQE Ethernet Segment size");
        static_assert(MLX5_WQE_DSEG_SIZE == MLX5_WSEG_SIZE,
                      "invalid WQE Data Segment size");
        static_assert(MLX5_WQE_SIZE == 4 * MLX5_WSEG_SIZE,
                      "invalid WQE size");
        assert(priv);
        if (tx_offloads & DEV_TX_OFFLOAD_MULTI_SEGS) {
                /* We should support Multi-Segment Packets. */
                olx |= MLX5_TXOFF_CONFIG_MULTI;
        }
        if (tx_offloads & (DEV_TX_OFFLOAD_TCP_TSO |
                           DEV_TX_OFFLOAD_VXLAN_TNL_TSO |
                           DEV_TX_OFFLOAD_GRE_TNL_TSO |
                           DEV_TX_OFFLOAD_IP_TNL_TSO |
                           DEV_TX_OFFLOAD_UDP_TNL_TSO)) {
                /* We should support TCP Send Offload. */
                olx |= MLX5_TXOFF_CONFIG_TSO;
        }
        if (tx_offloads & (DEV_TX_OFFLOAD_IP_TNL_TSO |
                           DEV_TX_OFFLOAD_UDP_TNL_TSO |
                           DEV_TX_OFFLOAD_OUTER_IPV4_CKSUM)) {
                /* We should support Software Parser for Tunnels. */
                olx |= MLX5_TXOFF_CONFIG_SWP;
        }
        if (tx_offloads & (DEV_TX_OFFLOAD_IPV4_CKSUM |
                           DEV_TX_OFFLOAD_UDP_CKSUM |
                           DEV_TX_OFFLOAD_TCP_CKSUM |
                           DEV_TX_OFFLOAD_OUTER_IPV4_CKSUM)) {
                /* We should support IP/TCP/UDP Checksums. */
                olx |= MLX5_TXOFF_CONFIG_CSUM;
        }
        if (tx_offloads & DEV_TX_OFFLOAD_VLAN_INSERT) {
                /* We should support VLAN insertion. */
                olx |= MLX5_TXOFF_CONFIG_VLAN;
        }
        if (priv->txqs_n && (*priv->txqs)[0]) {
                struct mlx5_txq_data *txd = (*priv->txqs)[0];

                if (txd->inlen_send) {
                        /*
                         * Check the data inline requirements. Data inline
                         * is enabled on per device basis, we can check
                         * the first Tx queue only.
                         *
                         * If device does not support VLAN insertion in WQE
                         * and some queues are requested to perform VLAN
                         * insertion offload than inline must be enabled.
                         */
                        olx |= MLX5_TXOFF_CONFIG_INLINE;
                }
        }
        if (config->mps == MLX5_MPW_ENHANCED &&
            config->txq_inline_min <= 0) {
                /*
                 * The NIC supports Enhanced Multi-Packet Write
                 * and does not require minimal inline data.
                 */
                olx |= MLX5_TXOFF_CONFIG_EMPW;
        }
        if (rte_flow_dynf_metadata_avail()) {
                /* We should support Flow metadata. */
                olx |= MLX5_TXOFF_CONFIG_METADATA;
        }
        if (config->mps == MLX5_MPW) {
                /*
                 * The NIC supports Legacy Multi-Packet Write.
                 * The MLX5_TXOFF_CONFIG_MPW controls the
                 * descriptor building method in combination
                 * with MLX5_TXOFF_CONFIG_EMPW.
                 */
                if (!(olx & (MLX5_TXOFF_CONFIG_TSO |
                             MLX5_TXOFF_CONFIG_SWP |
                             MLX5_TXOFF_CONFIG_VLAN |
                             MLX5_TXOFF_CONFIG_METADATA)))
                        olx |= MLX5_TXOFF_CONFIG_EMPW |
                               MLX5_TXOFF_CONFIG_MPW;
        }
        /*
         * Scan the routines table to find the minimal
         * satisfying routine with requested offloads.
         */
        m = RTE_DIM(txoff_func);
        for (i = 0; i < RTE_DIM(txoff_func); i++) {
                unsigned int tmp;

                tmp = txoff_func[i].olx;
                if (tmp == olx) {
                        /* Meets requested offloads exactly.*/
                        m = i;
                        break;
                }
                if ((tmp & olx) != olx) {
                        /* Does not meet requested offloads at all. */
                        continue;
                }
                if ((olx ^ tmp) & MLX5_TXOFF_CONFIG_EMPW)
                        /* Do not enable eMPW if not configured. */
                        continue;
                if ((olx ^ tmp) & MLX5_TXOFF_CONFIG_INLINE)
                        /* Do not enable inlining if not configured. */
                        continue;
                /*
                 * Some routine meets the requirements.
                 * Check whether it has minimal amount
                 * of not requested offloads.
                 */
                tmp = __builtin_popcountl(tmp & ~olx);
                if (m >= RTE_DIM(txoff_func) || tmp < diff) {
                        /* First or better match, save and continue. */
                        m = i;
                        diff = tmp;
                        continue;
                }
                if (tmp == diff) {
                        tmp = txoff_func[i].olx ^ txoff_func[m].olx;
                        if (__builtin_ffsl(txoff_func[i].olx & ~tmp) <
                            __builtin_ffsl(txoff_func[m].olx & ~tmp)) {
                                /* Lighter not requested offload. */
                                m = i;
                        }
                }
        }
        if (m >= RTE_DIM(txoff_func)) {
                DRV_LOG(DEBUG, "port %u has no selected Tx function"
                               " for requested offloads %04X",
                                dev->data->port_id, olx);
                return NULL;
        }
        DRV_LOG(DEBUG, "port %u has selected Tx function"
                       " supporting offloads %04X/%04X",
                        dev->data->port_id, olx, txoff_func[m].olx);
        if (txoff_func[m].olx & MLX5_TXOFF_CONFIG_MULTI)
                DRV_LOG(DEBUG, "\tMULTI (multi segment)");
        if (txoff_func[m].olx & MLX5_TXOFF_CONFIG_TSO)
                DRV_LOG(DEBUG, "\tTSO   (TCP send offload)");
        if (txoff_func[m].olx & MLX5_TXOFF_CONFIG_SWP)
                DRV_LOG(DEBUG, "\tSWP   (software parser)");
        if (txoff_func[m].olx & MLX5_TXOFF_CONFIG_CSUM)
                DRV_LOG(DEBUG, "\tCSUM  (checksum offload)");
        if (txoff_func[m].olx & MLX5_TXOFF_CONFIG_INLINE)
                DRV_LOG(DEBUG, "\tINLIN (inline data)");
        if (txoff_func[m].olx & MLX5_TXOFF_CONFIG_VLAN)
                DRV_LOG(DEBUG, "\tVLANI (VLAN insertion)");
        if (txoff_func[m].olx & MLX5_TXOFF_CONFIG_METADATA)
                DRV_LOG(DEBUG, "\tMETAD (tx Flow metadata)");
        if (txoff_func[m].olx & MLX5_TXOFF_CONFIG_EMPW) {
                if (txoff_func[m].olx & MLX5_TXOFF_CONFIG_MPW)
                        DRV_LOG(DEBUG, "\tMPW   (Legacy MPW)");
                else
                        DRV_LOG(DEBUG, "\tEMPW  (Enhanced MPW)");
        }
        return txoff_func[m].func;
}