From: Eric Dumazet Date: Mon, 13 Jun 2016 03:01:25 +0000 (-0700) Subject: net_sched: fix pfifo_head_drop behavior vs backlog X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=6c0d54f1897d229748d4f41ef919078db6db2123;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git net_sched: fix pfifo_head_drop behavior vs backlog 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 Cc: WANG Cong Cc: Jamal Hadi Salim Acked-by: Cong Wang Signed-off-by: David S. Miller --- diff --git a/net/sched/sch_fifo.c b/net/sched/sch_fifo.c index 2177eac0a61e..2e4bd2c0a50c 100644 --- a/net/sched/sch_fifo.c +++ b/net/sched/sch_fifo.c @@ -37,14 +37,18 @@ static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch) 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; }