net/mlx5: Don't unlock fte while still using it

commit 0fd758d6 upstream.

When adding a new rule to an fte, we need to hold the fte lock
until we add that rule to the fte and increase the fte ref count.

Fixes: 0c56b975 ("net/mlx5_core: Introduce flow steering API")
Signed-off-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -1110,9 +1110,8 @@ static struct mlx5_flow_rule *add_rule_fg(struct mlx5_flow_group *fg,
 				return rule;
 			}
 			rule = add_rule_fte(fte, fg, dest);
-			unlock_ref_node(&fte->node);
 			if (IS_ERR(rule))
-				goto unlock_fg;
+				goto unlock_fte;
 			else
 				goto add_rule;
 		}
@@ -1130,6 +1129,7 @@ static struct mlx5_flow_rule *add_rule_fg(struct mlx5_flow_group *fg,
 		goto unlock_fg;
 	}
 	tree_init_node(&fte->node, 0, del_fte);
+	nested_lock_ref_node(&fte->node, FS_MUTEX_CHILD);
 	rule = add_rule_fte(fte, fg, dest);
 	if (IS_ERR(rule)) {
 		kfree(fte);
@@ -1142,6 +1142,8 @@ static struct mlx5_flow_rule *add_rule_fg(struct mlx5_flow_group *fg,
 	list_add(&fte->node.list, prev);
 add_rule:
 	tree_add_node(&rule->node, &fte->node);
+unlock_fte:
+	unlock_ref_node(&fte->node);
 unlock_fg:
 	unlock_ref_node(&fg->node);
 	return rule;