From: Petr Machata <petrm@mellanox.com>
Date: Fri, 24 Jan 2020 15:23:05 +0200
Subject: net: sched: sch_tbf: Don't overwrite backlog before dumping
Patch-mainline: v5.6-rc1
Git-commit: c2070152747ebc294f018e4b28bf2d9f719a6b36
References: bsc#1154353

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/sched/sch_tbf.c |    1 -
 1 file changed, 1 deletion(-)

--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -443,7 +443,6 @@ static int tbf_dump(struct Qdisc *sch, s
 	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;