net/mlx5: fix Rx scatter mode validation

If the mbuf size of the Rx mempool supplied by the user in the Rx setup
is unable to contain the maximum Rx packet length in addition to the
mbuf head-room, the Rx scatter offload must be configured. Otherwise,
there is not enough space in single mbuf to contain a packet with size
of the maximum Rx packet length.

The PMD did not return an error in the above mentioned case.

Return an error in the above case.

Fixes: 7d6bf6b866b8 ("net/mlx5: add Multi-Packet Rx support")
Fixes: edad38fcd00e ("net/mlx: enhance Rx scatter mode detection")
Cc: stable@dpdk.org
Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>

diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
index 441f158..dc878f2 100644 (file)
--- a/drivers/net/mlx5/mlx5_rxq.c
+++ b/drivers/net/mlx5/mlx5_rxq.c
@@ -1616,7 +1616,20 @@ mlx5_rxq_new(struct rte_eth_dev *dev, uint16_t idx, uint16_t desc,
        uint64_t offloads = conf->offloads |
                           dev->data->dev_conf.rxmode.offloads;
        const int mprq_en = mlx5_check_mprq_support(dev) > 0;
-
+       unsigned int max_rx_pkt_len = dev->data->dev_conf.rxmode.max_rx_pkt_len;
+       unsigned int non_scatter_min_mbuf_size = max_rx_pkt_len +
+                                                       RTE_PKTMBUF_HEADROOM;
+
+       if (non_scatter_min_mbuf_size > mb_len && !(offloads &
+                                                   DEV_RX_OFFLOAD_SCATTER)) {
+               DRV_LOG(ERR, "port %u Rx queue %u: Scatter offload is not"
+                       " configured and no enough mbuf space(%u) to contain "
+                       "the maximum RX packet length(%u) with head-room(%u)",
+                       dev->data->port_id, idx, mb_len, max_rx_pkt_len,
+                       RTE_PKTMBUF_HEADROOM);
+               rte_errno = ENOSPC;
+               return NULL;
+       }
        tmpl = rte_calloc_socket("RXQ", 1,
                                 sizeof(*tmpl) +
                                 desc_n * sizeof(struct rte_mbuf *),
@@ -1642,9 +1655,8 @@ mlx5_rxq_new(struct rte_eth_dev *dev, uint16_t idx, uint16_t desc,
         *    stride.
         *  Otherwise, enable Rx scatter if necessary.
         */
-       assert(mb_len >= RTE_PKTMBUF_HEADROOM * strd_headroom_en);
-       mprq_stride_size = dev->data->dev_conf.rxmode.max_rx_pkt_len +
-                               RTE_PKTMBUF_HEADROOM * strd_headroom_en;
+       mprq_stride_size = max_rx_pkt_len + RTE_PKTMBUF_HEADROOM *
+                               strd_headroom_en;
        if (mprq_en &&
            desc > (1U << config->mprq.stride_num_n) &&
            mprq_stride_size <= (1U << config->mprq.max_stride_size_n)) {
@@ -1666,13 +1678,10 @@ mlx5_rxq_new(struct rte_eth_dev *dev, uint16_t idx, uint16_t desc,
                        " strd_num_n = %u, strd_sz_n = %u",
                        dev->data->port_id, idx,
                        tmpl->rxq.strd_num_n, tmpl->rxq.strd_sz_n);
-       } else if (dev->data->dev_conf.rxmode.max_rx_pkt_len <=
-                  (mb_len - RTE_PKTMBUF_HEADROOM)) {
+       } else if (max_rx_pkt_len <= (mb_len - RTE_PKTMBUF_HEADROOM)) {
                tmpl->rxq.sges_n = 0;
        } else if (offloads & DEV_RX_OFFLOAD_SCATTER) {
-               unsigned int size =
-                       RTE_PKTMBUF_HEADROOM +
-                       dev->data->dev_conf.rxmode.max_rx_pkt_len;
+               unsigned int size = non_scatter_min_mbuf_size;
                unsigned int sges_n;
 
                /*
@@ -1684,24 +1693,16 @@ mlx5_rxq_new(struct rte_eth_dev *dev, uint16_t idx, uint16_t desc,
                /* Make sure rxq.sges_n did not overflow. */
                size = mb_len * (1 << tmpl->rxq.sges_n);
                size -= RTE_PKTMBUF_HEADROOM;
-               if (size < dev->data->dev_conf.rxmode.max_rx_pkt_len) {
+               if (size < max_rx_pkt_len) {
                        DRV_LOG(ERR,
                                "port %u too many SGEs (%u) needed to handle"
                                " requested maximum packet size %u",
                                dev->data->port_id,
                                1 << sges_n,
-                               dev->data->dev_conf.rxmode.max_rx_pkt_len);
+                               max_rx_pkt_len);
                        rte_errno = EOVERFLOW;
                        goto error;
                }
-       } else {
-               DRV_LOG(WARNING,
-                       "port %u the requested maximum Rx packet size (%u) is"
-                       " larger than a single mbuf (%u) and scattered mode has"
-                       " not been requested",
-                       dev->data->port_id,
-                       dev->data->dev_conf.rxmode.max_rx_pkt_len,
-                       mb_len - RTE_PKTMBUF_HEADROOM);
        }
        if (mprq_en && !mlx5_rxq_mprq_enabled(&tmpl->rxq))
                DRV_LOG(WARNING,