net/mlx5: fix secondary process initialization ordering

[ upstream commit 69b44d6 ]

The memory barrier is used to ensure that the response is returned
only after the Tx/Rx function is set, it should place after the Rx/Tx
function is set.

Fixes: 2aac5b5 ("net/mlx5: sync stop/start with secondary process")

Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>

drivers/net/mlx5/linux/mlx5_mp_os.c

@@ -130,7 +130,6 @@ struct rte_mp_msg mp_res;
 	switch (param->type) {
 	case MLX5_MP_REQ_START_RXTX:
 		DRV_LOG(INFO, "port %u starting datapath", dev->data->port_id);
-		rte_mb();
 		dev->rx_pkt_burst = mlx5_select_rx_function(dev);
 		dev->tx_pkt_burst = mlx5_select_tx_function(dev);
 		ppriv = (struct mlx5_proc_priv *)dev->process_private;
@@ -147,6 +146,7 @@ struct rte_mp_msg mp_res;
 				return -rte_errno;
 			}
 		}
+		rte_mb();
 		mp_init_msg(&priv->mp_id, &mp_res, param->type);
 		res->result = 0;
 		ret = rte_mp_reply(&mp_res, peer);