net: sched: sch_tbf: Don't overwrite backlog before dumping

In 2011, in commit b0460e4484 ("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 8d5958f424 ("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>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Petr Machata 2020-01-24 15:23:05 +02:00 committed by David S. Miller
parent 2f64ab27c8
commit c207015274

View File

@ -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;