[PATCH net-next 1/3] net: sched: ensure n arg not empty before call bind_class

[Zhengchao Shao <shaozhengchao@xxxxxxxxxx>]

All bind_class callbacks are directly returned when n arg is empty.
Therefore, bind_class is invoked only when n arg is not empty.

Signed-off-by: Zhengchao Shao <shaozhengchao@xxxxxxxxxx>
---
 net/sched/sch_api.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index db1569fac57c..f9d5403bb1b7 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1898,7 +1898,7 @@ static int tcf_node_bind(struct tcf_proto *tp, void *n, struct tcf_walker *arg)
 {
 	struct tcf_bind_args *a = (void *)arg;
 
-	if (tp->ops->bind_class) {
+	if (n && tp->ops->bind_class) {
 		struct Qdisc *q = tcf_block_q(tp->chain->block);
 
 		sch_tree_lock(q);
-- 
2.17.1