net/mlx5: fix sync when handling Tx completions

Function mlx5_tx_complete() reads completion entry information
from Tx queue.
For some processors not having strongly-ordered memory model,
there has to be a memory barrier between reading the entry index
and the entry fields, in order to guarantee data is valid.

Fixes: 54d3fe948dba ("net/mlx5: poll completion queue once per a call")
Cc: stable@dpdk.org
Signed-off-by: Dekel Peled <dekelp@mellanox.com>
Acked-by: Shahaf Shuler <shahafs@mellanox.com>

diff --git a/drivers/net/mlx5/mlx5_rxtx.h b/drivers/net/mlx5/mlx5_rxtx.h
index c0e1adf140a1f522d0cffe853aefb7a6bb858a69..53115dde3d30f93d3e80c8de8489a1a2eb871ac9 100644 (file)
--- a/drivers/net/mlx5/mlx5_rxtx.h
+++ b/drivers/net/mlx5/mlx5_rxtx.h
@@ -568,6 +568,7 @@ mlx5_tx_complete(struct mlx5_txq_data *txq)
        }
 #endif /* NDEBUG */
        ++cq_ci;
+       rte_cio_rmb();
        txq->wqe_pi = rte_be_to_cpu_16(cqe->wqe_counter);
        ctrl = (volatile struct mlx5_wqe_ctrl *)
                tx_mlx5_wqe(txq, txq->wqe_pi);