mlx4_en: Fix a race at restart task

The query whether the port is up or not should be done at
the execution of the restart task and not when it is queued.
Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/mlx4/en_netdev.c

@@ -348,11 +348,9 @@ static void mlx4_en_tx_timeout(struct net_device *dev)
 	if (netif_msg_timer(priv))
 		mlx4_warn(mdev, "Tx timeout called on port:%d\n", priv->port);
 
-	if (netif_carrier_ok(dev)) {
 	priv->port_stats.tx_timeout++;
 	mlx4_dbg(DRV, priv, "Scheduling watchdog\n");
 	queue_work(mdev->workqueue, &priv->watchdog_task);
-	}
 }
 
 
@@ -761,9 +759,14 @@ static void mlx4_en_restart(struct work_struct *work)
 	struct net_device *dev = priv->dev;
 
 	mlx4_dbg(DRV, priv, "Watchdog task called for port %d\n", priv->port);
+
+	mutex_lock(&mdev->state_lock);
+	if (priv->port_up) {
 		mlx4_en_stop_port(dev);
 		if (mlx4_en_start_port(dev))
 			mlx4_err(mdev, "Failed restarting port %d\n", priv->port);
+	}
+	mutex_unlock(&mdev->state_lock);
 }