net/mlx5: check remaining space while processing Tx burst

The space necessary to store segmented packets cannot be known in advance
and must be verified for each of them.

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>

diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c
index 4934d34e3356403c4bd8379daac531a7388e9670..f270ef933f04799c549800f2476bf1a294e40987 100644 (file)
--- a/drivers/net/mlx5/mlx5_rxtx.c
+++ b/drivers/net/mlx5/mlx5_rxtx.c
@@ -585,50 +585,51 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
        struct txq *txq = (struct txq *)dpdk_txq;
        uint16_t elts_head = txq->elts_head;
        const unsigned int elts_n = txq->elts_n;
-       unsigned int i;
+       unsigned int i = 0;
        unsigned int max;
        unsigned int comp;
        volatile union mlx5_wqe *wqe;
-       struct rte_mbuf *buf;
 
        if (unlikely(!pkts_n))
                return 0;
-       buf = pkts[0];
        /* Prefetch first packet cacheline. */
        tx_prefetch_cqe(txq, txq->cq_ci);
        tx_prefetch_cqe(txq, txq->cq_ci + 1);
-       rte_prefetch0(buf);
+       rte_prefetch0(*pkts);
        /* Start processing. */
        txq_complete(txq);
        max = (elts_n - (elts_head - txq->elts_tail));
        if (max > elts_n)
                max -= elts_n;
-       assert(max >= 1);
-       assert(max <= elts_n);
-       /* Always leave one free entry in the ring. */
-       --max;
-       if (max == 0)
-               return 0;
-       if (max > pkts_n)
-               max = pkts_n;
-       for (i = 0; (i != max); ++i) {
-               unsigned int elts_head_next = (elts_head + 1) & (elts_n - 1);
+       do {
+               struct rte_mbuf *buf;
+               unsigned int elts_head_next;
                uintptr_t addr;
                uint32_t length;
                uint32_t lkey;
 
+               /*
+                * Make sure there is enough room to store this packet and
+                * that one ring entry remains unused.
+                */
+               if (max < 1 + 1)
+                       break;
+               --max;
+               --pkts_n;
+               buf = *(pkts++);
+               elts_head_next = (elts_head + 1) & (elts_n - 1);
                wqe = &(*txq->wqes)[txq->wqe_ci & (txq->wqe_n - 1)];
                rte_prefetch0(wqe);
-               if (i + 1 < max)
-                       rte_prefetch0(pkts[i + 1]);
+               if (pkts_n)
+                       rte_prefetch0(*pkts);
                /* Retrieve buffer information. */
                addr = rte_pktmbuf_mtod(buf, uintptr_t);
                length = DATA_LEN(buf);
                /* Update element. */
                (*txq->elts)[elts_head] = buf;
                /* Prefetch next buffer data. */
-               if (i + 1 < max)
-                       rte_prefetch0(rte_pktmbuf_mtod(pkts[i + 1],
+               if (pkts_n)
+                       rte_prefetch0(rte_pktmbuf_mtod(*pkts,
                                                       volatile void *));
                /* Retrieve Memory Region key for this memory pool. */
                lkey = txq_mp2mr(txq, txq_mb2mp(buf));
@@ -652,8 +653,8 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
                txq->stats.obytes += length;
 #endif
                elts_head = elts_head_next;
-               buf = pkts[i + 1];
-       }
+               ++i;
+       } while (pkts_n);
        /* Take a shortcut if nothing must be sent. */
        if (unlikely(i == 0))
                return 0;
@@ -697,44 +698,45 @@ mlx5_tx_burst_inline(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
        struct txq *txq = (struct txq *)dpdk_txq;
        uint16_t elts_head = txq->elts_head;
        const unsigned int elts_n = txq->elts_n;
-       unsigned int i;
+       unsigned int i = 0;
        unsigned int max;
        unsigned int comp;
        volatile union mlx5_wqe *wqe;
-       struct rte_mbuf *buf;
        unsigned int max_inline = txq->max_inline;
 
        if (unlikely(!pkts_n))
                return 0;
-       buf = pkts[0];
        /* Prefetch first packet cacheline. */
        tx_prefetch_cqe(txq, txq->cq_ci);
        tx_prefetch_cqe(txq, txq->cq_ci + 1);
-       rte_prefetch0(buf);
+       rte_prefetch0(*pkts);
        /* Start processing. */
        txq_complete(txq);
        max = (elts_n - (elts_head - txq->elts_tail));
        if (max > elts_n)
                max -= elts_n;
-       assert(max >= 1);
-       assert(max <= elts_n);
-       /* Always leave one free entry in the ring. */
-       --max;
-       if (max == 0)
-               return 0;
-       if (max > pkts_n)
-               max = pkts_n;
-       for (i = 0; (i != max); ++i) {
-               unsigned int elts_head_next = (elts_head + 1) & (elts_n - 1);
+       do {
+               struct rte_mbuf *buf;
+               unsigned int elts_head_next;
                uintptr_t addr;
                uint32_t length;
                uint32_t lkey;
 
+               /*
+                * Make sure there is enough room to store this packet and
+                * that one ring entry remains unused.
+                */
+               if (max < 1 + 1)
+                       break;
+               --max;
+               --pkts_n;
+               buf = *(pkts++);
+               elts_head_next = (elts_head + 1) & (elts_n - 1);
                wqe = &(*txq->wqes)[txq->wqe_ci & (txq->wqe_n - 1)];
                tx_prefetch_wqe(txq, txq->wqe_ci);
                tx_prefetch_wqe(txq, txq->wqe_ci + 1);
-               if (i + 1 < max)
-                       rte_prefetch0(pkts[i + 1]);
+               if (pkts_n)
+                       rte_prefetch0(*pkts);
                /* Should we enable HW CKSUM offload */
                if (buf->ol_flags &
                    (PKT_TX_IP_CKSUM | PKT_TX_TCP_CKSUM | PKT_TX_UDP_CKSUM)) {
@@ -750,8 +752,8 @@ mlx5_tx_burst_inline(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
                /* Update element. */
                (*txq->elts)[elts_head] = buf;
                /* Prefetch next buffer data. */
-               if (i + 1 < max)
-                       rte_prefetch0(rte_pktmbuf_mtod(pkts[i + 1],
+               if (pkts_n)
+                       rte_prefetch0(rte_pktmbuf_mtod(*pkts,
                                                       volatile void *));
                if (length <= max_inline) {
                        if (buf->ol_flags & PKT_TX_VLAN_PKT)
@@ -771,12 +773,12 @@ mlx5_tx_burst_inline(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
                }
                wqe->inl.ctrl.data[2] = 0;
                elts_head = elts_head_next;
-               buf = pkts[i + 1];
 #ifdef MLX5_PMD_SOFT_COUNTERS
                /* Increment sent bytes counter. */
                txq->stats.obytes += length;
 #endif
-       }
+               ++i;
+       } while (pkts_n);
        /* Take a shortcut if nothing must be sent. */
        if (unlikely(i == 0))
                return 0;
@@ -887,13 +889,15 @@ mlx5_tx_burst_mpw(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
        struct txq *txq = (struct txq *)dpdk_txq;
        uint16_t elts_head = txq->elts_head;
        const unsigned int elts_n = txq->elts_n;
-       unsigned int i;
+       unsigned int i = 0;
        unsigned int max;
        unsigned int comp;
        struct mlx5_mpw mpw = {
                .state = MLX5_MPW_STATE_CLOSED,
        };
 
+       if (unlikely(!pkts_n))
+               return 0;
        /* Prefetch first packet cacheline. */
        tx_prefetch_cqe(txq, txq->cq_ci);
        tx_prefetch_wqe(txq, txq->wqe_ci);
@@ -903,22 +907,24 @@ mlx5_tx_burst_mpw(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
        max = (elts_n - (elts_head - txq->elts_tail));
        if (max > elts_n)
                max -= elts_n;
-       assert(max >= 1);
-       assert(max <= elts_n);
-       /* Always leave one free entry in the ring. */
-       --max;
-       if (max == 0)
-               return 0;
-       if (max > pkts_n)
-               max = pkts_n;
-       for (i = 0; (i != max); ++i) {
-               struct rte_mbuf *buf = pkts[i];
+       do {
+               struct rte_mbuf *buf;
                volatile struct mlx5_wqe_data_seg *dseg;
-               unsigned int elts_head_next = (elts_head + 1) & (elts_n - 1);
+               unsigned int elts_head_next;
                uintptr_t addr;
                uint32_t length;
                uint32_t cs_flags = 0;
 
+               /*
+                * Make sure there is enough room to store this packet and
+                * that one ring entry remains unused.
+                */
+               if (max < 1 + 1)
+                       break;
+               --max;
+               --pkts_n;
+               buf = *(pkts++);
+               elts_head_next = (elts_head + 1) & (elts_n - 1);
                /* Should we enable HW CKSUM offload */
                if (buf->ol_flags &
                    (PKT_TX_IP_CKSUM | PKT_TX_TCP_CKSUM | PKT_TX_UDP_CKSUM))
@@ -951,7 +957,8 @@ mlx5_tx_burst_mpw(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
                /* Increment sent bytes counter. */
                txq->stats.obytes += length;
 #endif
-       }
+               ++i;
+       } while (pkts_n);
        /* Take a shortcut if nothing must be sent. */
        if (unlikely(i == 0))
                return 0;
@@ -1059,7 +1066,7 @@ mlx5_tx_burst_mpw_inline(void *dpdk_txq, struct rte_mbuf **pkts,
        struct txq *txq = (struct txq *)dpdk_txq;
        uint16_t elts_head = txq->elts_head;
        const unsigned int elts_n = txq->elts_n;
-       unsigned int i;
+       unsigned int i = 0;
        unsigned int max;
        unsigned int comp;
        unsigned int inline_room = txq->max_inline;
@@ -1067,6 +1074,8 @@ mlx5_tx_burst_mpw_inline(void *dpdk_txq, struct rte_mbuf **pkts,
                .state = MLX5_MPW_STATE_CLOSED,
        };
 
+       if (unlikely(!pkts_n))
+               return 0;
        /* Prefetch first packet cacheline. */
        tx_prefetch_cqe(txq, txq->cq_ci);
        tx_prefetch_wqe(txq, txq->wqe_ci);
@@ -1076,21 +1085,23 @@ mlx5_tx_burst_mpw_inline(void *dpdk_txq, struct rte_mbuf **pkts,
        max = (elts_n - (elts_head - txq->elts_tail));
        if (max > elts_n)
                max -= elts_n;
-       assert(max >= 1);
-       assert(max <= elts_n);
-       /* Always leave one free entry in the ring. */
-       --max;
-       if (max == 0)
-               return 0;
-       if (max > pkts_n)
-               max = pkts_n;
-       for (i = 0; (i != max); ++i) {
-               struct rte_mbuf *buf = pkts[i];
-               unsigned int elts_head_next = (elts_head + 1) & (elts_n - 1);
+       do {
+               struct rte_mbuf *buf;
+               unsigned int elts_head_next;
                uintptr_t addr;
                uint32_t length;
                uint32_t cs_flags = 0;
 
+               /*
+                * Make sure there is enough room to store this packet and
+                * that one ring entry remains unused.
+                */
+               if (max < 1 + 1)
+                       break;
+               --max;
+               --pkts_n;
+               buf = *(pkts++);
+               elts_head_next = (elts_head + 1) & (elts_n - 1);
                /* Should we enable HW CKSUM offload */
                if (buf->ol_flags &
                    (PKT_TX_IP_CKSUM | PKT_TX_TCP_CKSUM | PKT_TX_UDP_CKSUM))
@@ -1177,7 +1188,8 @@ mlx5_tx_burst_mpw_inline(void *dpdk_txq, struct rte_mbuf **pkts,
                /* Increment sent bytes counter. */
                txq->stats.obytes += length;
 #endif
-       }
+               ++i;
+       } while (pkts_n);
        /* Take a shortcut if nothing must be sent. */
        if (unlikely(i == 0))
                return 0;