[PATCH v5 net 2/6] net/sched: sch_clsact: Only create under TC_H_CLSACT

[Peilin Ye]

From: Peilin Ye <peilin.ye@xxxxxxxxxxxxx>

clsact Qdiscs are only supposed to be created under TC_H_CLSACT (which
equals TC_H_INGRESS).  Return -EOPNOTSUPP if 'parent' is not
TC_H_CLSACT.

Fixes: 1f211a1b929c ("net, sched: add clsact qdisc")
Signed-off-by: Peilin Ye <peilin.ye@xxxxxxxxxxxxx>
---
change in v5:
  - avoid underflowing @egress_needed_key in ->destroy(), reported by
    Pedro

change in v3, v4:
  - add in-body From: tag

 net/sched/sch_ingress.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/sched/sch_ingress.c b/net/sched/sch_ingress.c
index f9ef6deb2770..35963929e117 100644
--- a/net/sched/sch_ingress.c
+++ b/net/sched/sch_ingress.c
@@ -225,6 +225,9 @@ static int clsact_init(struct Qdisc *sch, struct nlattr *opt,
 	struct net_device *dev = qdisc_dev(sch);
 	int err;
 
+	if (sch->parent != TC_H_CLSACT)
+		return -EOPNOTSUPP;
+
 	net_inc_ingress_queue();
 	net_inc_egress_queue();
 
@@ -254,6 +257,9 @@ static void clsact_destroy(struct Qdisc *sch)
 {
 	struct clsact_sched_data *q = qdisc_priv(sch);
 
+	if (sch->parent != TC_H_CLSACT)
+		return;
+
 	tcf_block_put_ext(q->egress_block, sch, &q->egress_block_info);
 	tcf_block_put_ext(q->ingress_block, sch, &q->ingress_block_info);
 
-- 
2.20.1