From 3f0947c3ffaed33c1c38b79e4b17f75ba072d3e9 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Mon, 24 Nov 2008 15:46:08 -0800 Subject: [PATCH] pkt_sched: sch_drr: fix drr_dequeue loop() Jarek Poplawski points out: If all child qdiscs of sch_drr are non-work-conserving (e.g. sch_tbf) drr_dequeue() will busy-loop waiting for skbs instead of leaving the job for a watchdog. Checking for list_empty() in each loop isn't necessary either, because this can never be true except the first time. Using non-work-conserving qdiscs as children of DRR makes no sense, simply bail out in that case. Reported-by: Jarek Poplawski Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- net/sched/sch_drr.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/net/sched/sch_drr.c b/net/sched/sch_drr.c index 37e6ab99bbea..e7a7e87b141a 100644 --- a/net/sched/sch_drr.c +++ b/net/sched/sch_drr.c @@ -373,11 +373,13 @@ static struct sk_buff *drr_dequeue(struct Qdisc *sch) struct sk_buff *skb; unsigned int len; - while (!list_empty(&q->active)) { + if (list_empty(&q->active)) + goto out; + while (1) { cl = list_first_entry(&q->active, struct drr_class, alist); skb = cl->qdisc->ops->peek(cl->qdisc); if (skb == NULL) - goto skip; + goto out; len = qdisc_pkt_len(skb); if (len <= cl->deficit) { @@ -390,9 +392,9 @@ static struct sk_buff *drr_dequeue(struct Qdisc *sch) } cl->deficit += cl->quantum; -skip: list_move_tail(&cl->alist, &q->active); } +out: return NULL; } -- 2.30.2