diff options
| author | Toke Høiland-Jørgensen <toke@redhat.com> | 2019-01-09 17:09:43 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-01-15 20:12:00 -0800 |
| commit | 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea (patch) | |
| tree | 29e8d6fccf9da0a9c19129f477a0ef0ae244464d /net/sched/sch_drr.c | |
| parent | f6bab199315b70fd83fe3ee0947bc84c7a35f3d4 (diff) | |
sched: Fix detection of empty queues in child qdiscs
Several qdiscs check on enqueue whether the packet was enqueued to a class
with an empty queue, in which case the class is activated. This is done by
checking if the qlen is exactly 1 after enqueue. However, if GSO splitting
is enabled in the child qdisc, a single packet can result in a qlen longer
than 1. This means the activation check fails, leading to a stalled queue.
Fix this by checking if the queue is empty *before* enqueue, and running
the activation logic if this was the case.
Reported-by: Pete Heist <pete@heistp.net>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/sch_drr.c')
| -rw-r--r-- | net/sched/sch_drr.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/net/sched/sch_drr.c b/net/sched/sch_drr.c index feaf47178653..09b800991065 100644 --- a/net/sched/sch_drr.c +++ b/net/sched/sch_drr.c @@ -354,6 +354,7 @@ static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct drr_sched *q = qdisc_priv(sch); struct drr_class *cl; int err = 0; + bool first; cl = drr_classify(skb, sch, &err); if (cl == NULL) { @@ -363,6 +364,7 @@ static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch, return err; } + first = !cl->qdisc->q.qlen; err = qdisc_enqueue(skb, cl->qdisc, to_free); if (unlikely(err != NET_XMIT_SUCCESS)) { if (net_xmit_drop_count(err)) { @@ -372,7 +374,7 @@ static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch, return err; } - if (cl->qdisc->q.qlen == 1) { + if (first) { list_add_tail(&cl->alist, &q->active); cl->deficit = cl->quantum; } |