[PATCH 4.19 115/140] sch_cake: Correctly update parent qlen when splitting GSO packets

Greg Kroah-Hartman
2019-12-16T18:06:05Z

From: Toke Høiland-Jørgensen <toke@redhat.com>

[ Upstream commit 8c6c37fdc20ec9ffaa342f827a8e20afe736fb0c ]

To ensure parent qdiscs have the same notion of the number of enqueued
packets even after splitting a GSO packet, update the qdisc tree with the
number of packets that was added due to the split.

Reported-by: Pete Heist <pete@heistp.net>
Tested-by: Pete Heist <pete@heistp.net>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/sched/sch_cake.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c
index 9fd37d91b5ed0..e4cf72b0675e1 100644
--- a/net/sched/sch_cake.c
+++ b/net/sched/sch_cake.c
@@ -1666,7 +1666,7 @@ static s32 cake_enqueue(struct sk_buff *skb, struct Qdisc *sch,
if (skb_is_gso(skb) && q->rate_flags & CAKE_FLAG_SPLIT_GSO) {
struct sk_buff *segs, *nskb;
netdev_features_t features = netif_skb_features(skb);
- unsigned int slen = 0;
+ unsigned int slen = 0, numsegs = 0;

segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
if (IS_ERR_OR_NULL(segs))
@@ -1682,6 +1682,7 @@ static s32 cake_enqueue(struct sk_buff *skb, struct Qdisc *sch,
flow_queue_add(flow, segs);

sch->q.qlen++;
+ numsegs++;
slen += segs->len;
q->buffer_used += segs->truesize;
b->packets++;
@@ -1695,7 +1696,7 @@ static s32 cake_enqueue(struct sk_buff *skb, struct Qdisc *sch,
sch->qstats.backlog += slen;
q->avg_window_bytes += slen;

- qdisc_tree_reduce_backlog(sch, 1, len);
+ qdisc_tree_reduce_backlog(sch, 1-numsegs, len-slen);
consume_skb(skb);
} else {
/* not splitting */
--
2.20.1