[PATCH 3.16 117/294] net_sched/sfq: update hierarchical backlog when drop packet

[Ben Hutchings]

3.16.50-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Konstantin Khlebnikov <khlebni...@yandex-team.ru>

commit 325d5dc3f7e7c2840b65e4a2988c082c2c0025c5 upstream.

When sfq_enqueue() drops head packet or packet from another queue it
have to update backlog at upper qdiscs too.

Fixes: 2ccccf5fb43f ("net_sched: update hierarchical backlog too")
Signed-off-by: Konstantin Khlebnikov <khlebni...@yandex-team.ru>
Acked-by: Eric Dumazet <eduma...@google.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
 net/sched/sch_sfq.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -460,6 +460,7 @@ congestion_drop:
                qdisc_drop(head, sch);
 
                slot_queue_add(slot, skb);
+               qdisc_tree_reduce_backlog(sch, 0, delta);
                return NET_XMIT_CN;
        }
 
@@ -491,8 +492,10 @@ enqueue:
        /* Return Congestion Notification only if we dropped a packet
         * from this flow.
         */
-       if (qlen != slot->qlen)
+       if (qlen != slot->qlen) {
+               qdisc_tree_reduce_backlog(sch, 0, dropped - qdisc_pkt_len(skb));
                return NET_XMIT_CN;
+       }
 
        /* As we dropped a packet, better let upper stack know this */
        qdisc_tree_reduce_backlog(sch, 1, dropped);