[PATCH net-next 01/14] net: sched: sch_tbf: Don't overwrite backlog before dumping

Ido Schimmel
2020-01-24T13:24:07Z

In 2011, in commit b0460e4484f9 ("sch_tbf: report backlog information"),
TBF started copying backlog depth from the child Qdisc before dumping, with
the motivation that the backlog was otherwise not visible in "tc -s qdisc
show".

Later, in 2016, in commit 8d5958f424b6 ("sch_tbf: update backlog as well"),
TBF got a full-blown backlog tracking. However it kept copying the child's
backlog over before dumping.

That line is now unnecessary, so remove it.

As shown in the following example, backlog is still reported correctly:

# tc -s qdisc show dev veth0 invisible
qdisc tbf 1: root refcnt 2 rate 1Mbit burst 128Kb lat 82.8s
Sent 505475370 bytes 406985 pkt (dropped 0, overlimits 812544 requeues 0)
backlog 81972b 66p requeues 0
qdisc bfifo 0: parent 1:1 limit 10Mb
Sent 505475370 bytes 406985 pkt (dropped 0, overlimits 0 requeues 0)
backlog 81972b 66p requeues 0

Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
---
net/sched/sch_tbf.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index 2cd94973795c..7ae317958090 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -441,7 +441,6 @@ static int tbf_dump(struct Qdisc *sch, struct sk_buff *skb)
struct nlattr *nest;
struct tc_tbf_qopt opt;

- sch->qstats.backlog = q->qdisc->qstats.backlog;
nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
if (nest == NULL)
goto nla_put_failure;
--
2.24.1