[PATCH net-next v3] net_sched: dsmark: use qdisc_dequeue_peeked()

[PATCH net-next v3] net_sched: dsmark: use qdisc_dequeue_peeked()

[Kyeong Yoo]

This fix is for dsmark similar to commit 3557619f0f6f7496ed453d4825e249
("net_sched: prio: use qdisc_dequeue_peeked")
and makes use of qdisc_dequeue_peeked() instead of direct dequeue() call.

First time, wrr peeks dsmark, which will then peek into sfq.
sfq dequeues an skb and it's stored in sch->gso_skb.
Next time, wrr tries to dequeue from dsmark, which will call sfq dequeue
directly. This results skipping the previously peeked skb.

So changed dsmark dequeue to call qdisc_dequeue_peeked() instead to use
peeked skb if exists.

Signed-off-by: Kyeong Yoo <kyeong.yoo@alliedtelesis.co.nz>
---
 net/sched/sch_dsmark.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/sch_dsmark.c b/net/sched/sch_dsmark.c
index f357f34..b204472 100644
--- a/net/sched/sch_dsmark.c
+++ b/net/sched/sch_dsmark.c
@@ -281,7 +281,7 @@ static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)
 
 	pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 
-	skb = p->q->ops->dequeue(p->q);
+	skb = qdisc_dequeue_peeked(p->q);
 	if (skb == NULL)
 		return NULL;
 

Re: [PATCH net-next v3] net_sched: dsmark: use qdisc_dequeue_peeked()

[David Miller]

From: Kyeong Yoo <kyeong.yoo@alliedtelesis.co.nz>
Date: Mon, 07 Mar 2016 17:07:57 +1300

> This fix is for dsmark similar to commit 3557619f0f6f7496ed453d4825e249
> ("net_sched: prio: use qdisc_dequeue_peeked")
> and makes use of qdisc_dequeue_peeked() instead of direct dequeue() call.
> 
> First time, wrr peeks dsmark, which will then peek into sfq.
> sfq dequeues an skb and it's stored in sch->gso_skb.
> Next time, wrr tries to dequeue from dsmark, which will call sfq dequeue
> directly. This results skipping the previously peeked skb.
> 
> So changed dsmark dequeue to call qdisc_dequeue_peeked() instead to use
> peeked skb if exists.
> 
> Signed-off-by: Kyeong Yoo <kyeong.yoo@alliedtelesis.co.nz>

Applied, thank you.