[PATCH] [trusty] (upstream) net/mlx5e: Avoid NULL pointer access in case of configuration failure

[Talat Batheesh]

From: Achiad Shochat <achiad at mellanox.com>

BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1528466

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 at mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz at mellanox.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit a1985740904342a884471348f6e038ee5d706c36)
Signed-off-by: Talat Batheesh <talatb at mellanox.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 876c0e1..521a97d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -1561,6 +1561,12 @@ 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_set_rx_mode_core(priv);
-- 
2.5.0