ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/target/linux/generic/pending-5.4/620-net_sched-codel-do-not-defer-queue-length-update.patch b/target/linux/generic/pending-5.4/620-net_sched-codel-do-not-defer-queue-length-update.patch
new file mode 100644
index 0000000..ca85b8a
--- /dev/null
+++ b/target/linux/generic/pending-5.4/620-net_sched-codel-do-not-defer-queue-length-update.patch
@@ -0,0 +1,86 @@
+From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
+Date: Mon, 21 Aug 2017 11:14:14 +0300
+Subject: [PATCH] net_sched/codel: do not defer queue length update
+
+When codel wants to drop last packet in ->dequeue() it cannot call
+qdisc_tree_reduce_backlog() right away - it will notify parent qdisc
+about zero qlen and HTB/HFSC will deactivate class. The same class will
+be deactivated second time by caller of ->dequeue(). Currently codel and
+fq_codel defer update. This triggers warning in HFSC when it's qlen != 0
+but there is no active classes.
+
+This patch update parent queue length immediately: just temporary increase
+qlen around qdisc_tree_reduce_backlog() to prevent first class deactivation
+if we have skb to return.
+
+This might open another problem in HFSC - now operation peek could fail and
+deactivate parent class.
+
+Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
+Link: https://bugzilla.kernel.org/show_bug.cgi?id=109581
+---
+
+--- a/net/sched/sch_codel.c
++++ b/net/sched/sch_codel.c
+@@ -95,11 +95,17 @@ static struct sk_buff *codel_qdisc_deque
+ &q->stats, qdisc_pkt_len, codel_get_enqueue_time,
+ drop_func, dequeue_func);
+
+- /* We cant call qdisc_tree_reduce_backlog() if our qlen is 0,
+- * or HTB crashes. Defer it for next round.
++ /* If our qlen is 0 qdisc_tree_reduce_backlog() will deactivate
++ * parent class, dequeue in parent qdisc will do the same if we
++ * return skb. Temporary increment qlen if we have skb.
+ */
+- if (q->stats.drop_count && sch->q.qlen) {
+- qdisc_tree_reduce_backlog(sch, q->stats.drop_count, q->stats.drop_len);
++ if (q->stats.drop_count) {
++ if (skb)
++ sch->q.qlen++;
++ qdisc_tree_reduce_backlog(sch, q->stats.drop_count,
++ q->stats.drop_len);
++ if (skb)
++ sch->q.qlen--;
+ q->stats.drop_count = 0;
+ q->stats.drop_len = 0;
+ }
+--- a/net/sched/sch_fq_codel.c
++++ b/net/sched/sch_fq_codel.c
+@@ -305,6 +305,21 @@ begin:
+ &flow->cvars, &q->cstats, qdisc_pkt_len,
+ codel_get_enqueue_time, drop_func, dequeue_func);
+
++ /* If our qlen is 0 qdisc_tree_reduce_backlog() will deactivate
++ * parent class, dequeue in parent qdisc will do the same if we
++ * return skb. Temporary increment qlen if we have skb.
++ */
++ if (q->cstats.drop_count) {
++ if (skb)
++ sch->q.qlen++;
++ qdisc_tree_reduce_backlog(sch, q->cstats.drop_count,
++ q->cstats.drop_len);
++ if (skb)
++ sch->q.qlen--;
++ q->cstats.drop_count = 0;
++ q->cstats.drop_len = 0;
++ }
++
+ if (!skb) {
+ /* force a pass through old_flows to prevent starvation */
+ if ((head == &q->new_flows) && !list_empty(&q->old_flows))
+@@ -315,15 +330,6 @@ begin:
+ }
+ qdisc_bstats_update(sch, skb);
+ flow->deficit -= qdisc_pkt_len(skb);
+- /* We cant call qdisc_tree_reduce_backlog() if our qlen is 0,
+- * or HTB crashes. Defer it for next round.
+- */
+- if (q->cstats.drop_count && sch->q.qlen) {
+- qdisc_tree_reduce_backlog(sch, q->cstats.drop_count,
+- q->cstats.drop_len);
+- q->cstats.drop_count = 0;
+- q->cstats.drop_len = 0;
+- }
+ return skb;
+ }
+