net/mlx5e: Avoid NULL pointer access in case of configuration failure

In case a configuration operation that involves closing and re-opening
resources (e.g RX/TX queue size change) fails at the re-opening stage
these resources will remain closed.
So when executing (following) configuration operations (e.g ifconfig
down) we cannot assume that these resources are available.
Signed-off-by: Achiad Shochat <achiad@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx5/core/en_main.c

@@ -1404,6 +1404,12 @@ int mlx5e_close_locked(struct net_device *netdev)
 {
 	struct mlx5e_priv *priv = netdev_priv(netdev);
 
+	/* May already be CLOSED in case a previous configuration operation
+	 * (e.g RX/TX queue size change) that involves close&open failed.
+	 */
+	if (!test_bit(MLX5E_STATE_OPENED, &priv->state))
+		return 0;
+
 	clear_bit(MLX5E_STATE_OPENED, &priv->state);
 
 	mlx5e_redirect_rqts(priv);