[dpdk-stable] [PATCH] net/mlx5: fix Tx when first segment size is too short

[Nelio Laranjeiro <nelio.laranjeiro@6wind.com>]

First segment size must be at least 18 bytes, packets not respecting this
are silently not sent by the NIC but counted as sent by the PMD.  The only
way to figure out is compiling the PMD in debug mode.

Cc: stable@dpdk.org
Fixes: 6579c27c11a5 ("net/mlx5: remove gather loop on segments")

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

---

v2: fix the commit log.
---
 drivers/net/mlx5/mlx5_rxtx.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c
index 823aac8..e2e8a22 100644
--- a/drivers/net/mlx5/mlx5_rxtx.c
+++ b/drivers/net/mlx5/mlx5_rxtx.c
@@ -485,7 +485,8 @@ mlx5_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
 #ifdef MLX5_PMD_SOFT_COUNTERS
 		total_length = length;
 #endif
-		assert(length >= MLX5_WQE_DWORD_SIZE);
+		if (length < (MLX5_WQE_DWORD_SIZE + 2))
+			break;
 		/* Update element. */
 		(*txq->elts)[elts_head] = buf;
 		elts_head = (elts_head + 1) & (elts_n - 1);
-- 
2.1.4