[PATCH v3] net/mlx5: Add error handling in mlx5_query_nic_vport_node_guid()

[Wentao Liang <vulab@iscas.ac.cn>]

The function mlx5_query_nic_vport_node_guid() calls the function
mlx5_query_nic_vport_context() but does not check its return value.
A proper implementation can be found in mlx5_nic_vport_query_local_lb().

Add error handling for mlx5_query_nic_vport_context(). If it fails, free
the out buffer via kvfree() and return error code.

Fixes: 9efa75254593 ("net/mlx5_core: Introduce access functions to query vport RoCE fields")
Cc: stable@vger.kernel.org # v4.5
Target: net
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
---
v3: Explicitly mention target branch. Change improper code.
v2: Remove redundant reassignment. Fix typo error.

 drivers/net/ethernet/mellanox/mlx5/core/vport.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/vport.c b/drivers/net/ethernet/mellanox/mlx5/core/vport.c
index 0d5f750faa45..66e44905c1f0 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/vport.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/vport.c
@@ -465,19 +465,22 @@ int mlx5_query_nic_vport_node_guid(struct mlx5_core_dev *mdev, u64 *node_guid)
 {
 	u32 *out;
 	int outlen = MLX5_ST_SZ_BYTES(query_nic_vport_context_out);
+	int err;
 
 	out = kvzalloc(outlen, GFP_KERNEL);
 	if (!out)
 		return -ENOMEM;
 
-	mlx5_query_nic_vport_context(mdev, 0, out);
+	ret = mlx5_query_nic_vport_context(mdev, 0, out);
+	if (err)
+		goto out;
 
 	*node_guid = MLX5_GET64(query_nic_vport_context_out, out,
 				nic_vport_context.node_guid);
-
+out:
 	kvfree(out);
 
-	return 0;
+	return err;
 }
 EXPORT_SYMBOL_GPL(mlx5_query_nic_vport_node_guid);
 
-- 
2.42.0.windows.2