Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 01/32] net_sched: fix pfifo_head_drop behavior vs backlog | Date | Wed, 6 Jul 2016 18:19:11 -0700 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet <edumazet@google.com>
[ Upstream commit 6c0d54f1897d229748d4f41ef919078db6db2123 ]
When the qdisc is full, we drop a packet at the head of the queue, queue the current skb and return NET_XMIT_CN
Now we track backlog on upper qdiscs, we need to call qdisc_tree_reduce_backlog(), even if the qlen did not change.
Fixes: 2ccccf5fb43f ("net_sched: update hierarchical backlog too") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: WANG Cong <xiyou.wangcong@gmail.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/sched/sch_fifo.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/net/sched/sch_fifo.c +++ b/net/sched/sch_fifo.c @@ -37,14 +37,18 @@ static int pfifo_enqueue(struct sk_buff static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc *sch) { + unsigned int prev_backlog; + if (likely(skb_queue_len(&sch->q) < sch->limit)) return qdisc_enqueue_tail(skb, sch); + prev_backlog = sch->qstats.backlog; /* queue full, remove one skb to fulfill the limit */ __qdisc_queue_drop_head(sch, &sch->q); qdisc_qstats_drop(sch); qdisc_enqueue_tail(skb, sch); + qdisc_tree_reduce_backlog(sch, 0, prev_backlog - sch->qstats.backlog); return NET_XMIT_CN; }
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