net/mlx4_en: Fix a race between napi poll function and RX ring cleanup

The RX rings were cleaned while there was still possible RX traffic completion
handling.
Change the sequance of events so that the port is closed and the QPs are being
stopped before RX cleanup.
Signed-off-by: NEugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: NAmir Vadai <amirv@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/en_netdev.c

@@ -1635,6 +1635,9 @@ void mlx4_en_stop_port(struct net_device *dev, int detach)
 		return;
 	}
 
+	/* close port*/
+	mlx4_CLOSE_PORT(mdev->dev, priv->port);
+
 	/* Synchronize with tx routine */
 	netif_tx_lock_bh(dev);
 	if (detach)
@@ -1735,14 +1738,11 @@ void mlx4_en_stop_port(struct net_device *dev, int detach)
 		}
 		local_bh_enable();
 
-		mlx4_en_deactivate_rx_ring(priv, &priv->rx_ring[i]);
 		while (test_bit(NAPI_STATE_SCHED, &cq->napi.state))
 			msleep(1);
+		mlx4_en_deactivate_rx_ring(priv, &priv->rx_ring[i]);
 		mlx4_en_deactivate_cq(priv, cq);
 	}
-
-	/* close port*/
-	mlx4_CLOSE_PORT(mdev->dev, priv->port);
 }
 
 static void mlx4_en_restart(struct work_struct *work)