[PATCH 4.9 21/33] net/mlx5: Avoid cleaning flow steering table twice during error flow

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Talat Batheesh <talatb@mellanox.com>

[ Upstream commit 9c26f5f89d01ca21560c6b8a8e4054c271cc3a9c ]

When we fail to initialize the RX root namespace, we need
to clean only that and not the entire flow steering.

Currently the code may try to clean the flow steering twice
on error witch leads to null pointer deference.
Make sure we clean correctly.

Fixes: fba53f7b5719 ("net/mlx5: Introduce mlx5_flow_steering structure")
Signed-off-by: Talat Batheesh <talatb@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/mellanox/mlx5/core/fs_core.c |   21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
@@ -153,6 +153,7 @@ static void del_rule(struct fs_node *nod
 static void del_flow_table(struct fs_node *node);
 static void del_flow_group(struct fs_node *node);
 static void del_fte(struct fs_node *node);
+static void cleanup_root_ns(struct mlx5_flow_root_namespace *root_ns);
 
 static void tree_init_node(struct fs_node *node,
 			   unsigned int refcount,
@@ -1690,24 +1691,28 @@ static int create_anchor_flow_table(stru
 
 static int init_root_ns(struct mlx5_flow_steering *steering)
 {
+	int err;
 
 	steering->root_ns = create_root_ns(steering, FS_FT_NIC_RX);
 	if (!steering->root_ns)
-		goto cleanup;
+		return -ENOMEM;
 
-	if (init_root_tree(steering, &root_fs, &steering->root_ns->ns.node))
-		goto cleanup;
+	err = init_root_tree(steering, &root_fs, &steering->root_ns->ns.node);
+	if (err)
+		goto out_err;
 
 	set_prio_attrs(steering->root_ns);
 
-	if (create_anchor_flow_table(steering))
-		goto cleanup;
+	err = create_anchor_flow_table(steering);
+	if (err)
+		goto out_err;
 
 	return 0;
 
-cleanup:
-	mlx5_cleanup_fs(steering->dev);
-	return -ENOMEM;
+out_err:
+	cleanup_root_ns(steering->root_ns);
+	steering->root_ns = NULL;
+	return err;
 }
 
 static void clean_tree(struct fs_node *node)