net/mlx5: mitigate Rx doorbell memory barrier

The RQ WQEs must be written in the memory before the HW gets the RQ
doorbell, hence a memory barrier should be triggered after the WQEs
writing and before the doorbell writing.

The current code used rte_wmb barrier which ensures that all the memory
stores were done while it is enough to use rte_cio_wmb barrier for the
local memory stores because the WQEs are in local memory.

CC: stable@dpdk.org
Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Shahaf Shuler <shahafs@mellanox.com>

diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
index 1ac4020..07adeb5 100644 (file)
--- a/drivers/net/mlx5/mlx5_rxq.c
+++ b/drivers/net/mlx5/mlx5_rxq.c
@@ -1076,7 +1076,7 @@ mlx5_rxq_ibv_new(struct rte_eth_dev *dev, uint16_t idx)
        rxq_data->decompressed = 0;
        /* Update doorbell counter. */
        rxq_data->rq_ci = wqe_n >> rxq_data->sges_n;
-       rte_wmb();
+       rte_cio_wmb();
        *rxq_data->rq_db = rte_cpu_to_be_32(rxq_data->rq_ci);
        DRV_LOG(DEBUG, "port %u rxq %u updated with %p", dev->data->port_id,
                idx, (void *)&tmpl);