From: Talat Batheesh <talatb@mellanox.com>
Date: Sun, 15 Apr 2018 11:26:19 +0300
Subject: net/mlx5: Avoid cleaning flow steering table twice during error flow
Patch-mainline: v4.17-rc4
Git-commit: 9c26f5f89d01ca21560c6b8a8e4054c271cc3a9c
References: bsc#1091532

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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlx5/core/fs_core.c |   23 +++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
@@ -180,6 +180,7 @@ static void del_sw_fte(struct fs_node *n
 static void del_sw_hw_rule(struct fs_node *node);
 static bool mlx5_flow_dests_cmp(struct mlx5_flow_destination *d1,
 				struct mlx5_flow_destination *d2);
+static void cleanup_root_ns(struct mlx5_flow_root_namespace *root_ns);
 static struct mlx5_flow_rule *
 find_flow_rule(struct fs_fte *fte,
 	       struct mlx5_flow_destination *dest);
@@ -2285,23 +2286,27 @@ 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)