From: Dust Li <dust.li@linux.alibaba.com>
Date: Thu, 28 Nov 2019 14:29:09 +0800
Subject: net: sched: fix `tc -s class show` no bstats on class with nolock
 subqueues
Git-commit: 14e54ab9143fa60794d13ea0a66c792a2046a8f3
Patch-mainline: 5.5-rc1
References: networking-stable-19_12_03

When a classful qdisc's child qdisc has set the flag
TCQ_F_CPUSTATS (pfifo_fast for example), the child qdisc's
cpu_bstats should be passed to gnet_stats_copy_basic(),
but many classful qdisc didn't do that. As a result,
`tc -s class show dev DEV` always return 0 for bytes and
packets in this case.

Pass the child qdisc's cpu_bstats to gnet_stats_copy_basic()
to fix this issue.

The qstats also has this problem, but it has been fixed
in 5dd431b6b9 ("net: sched: introduce and use qstats read...")
and bstats still remains buggy.

Fixes: 22e0f8b9322c ("net: sched: make bstats per cpu and estimator RCU safe")
Signed-off-by: Dust Li <dust.li@linux.alibaba.com>
Signed-off-by: Tony Lu <tonylu@linux.alibaba.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 net/sched/sch_mq.c     |    3 ++-
 net/sched/sch_mqprio.c |    4 ++--
 net/sched/sch_multiq.c |    2 +-
 net/sched/sch_prio.c   |    2 +-
 4 files changed, 6 insertions(+), 5 deletions(-)

--- a/net/sched/sch_mq.c
+++ b/net/sched/sch_mq.c
@@ -195,7 +195,8 @@ static int mq_dump_class_stats(struct Qd
 	struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
 
 	sch = dev_queue->qdisc_sleeping;
-	if (gnet_stats_copy_basic(&sch->running, d, NULL, &sch->bstats) < 0 ||
+	if (gnet_stats_copy_basic(&sch->running, d, sch->cpu_bstats,
+				  &sch->bstats) < 0 ||
 	    qdisc_qstats_copy(d, sch) < 0)
 		return -1;
 	return 0;
--- a/net/sched/sch_mqprio.c
+++ b/net/sched/sch_mqprio.c
@@ -370,8 +370,8 @@ static int mqprio_dump_class_stats(struc
 		struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
 
 		sch = dev_queue->qdisc_sleeping;
-		if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
-					  d, NULL, &sch->bstats) < 0 ||
+		if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch), d,
+					  sch->cpu_bstats, &sch->bstats) < 0 ||
 		    qdisc_qstats_copy(d, sch) < 0)
 			return -1;
 	}
--- a/net/sched/sch_multiq.c
+++ b/net/sched/sch_multiq.c
@@ -340,7 +340,7 @@ static int multiq_dump_class_stats(struc
 
 	cl_q = q->queues[cl - 1];
 	if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
-				  d, NULL, &cl_q->bstats) < 0 ||
+				  d, cl_q->cpu_bstats, &cl_q->bstats) < 0 ||
 	    qdisc_qstats_copy(d, cl_q) < 0)
 		return -1;
 
--- a/net/sched/sch_prio.c
+++ b/net/sched/sch_prio.c
@@ -298,7 +298,7 @@ static int prio_dump_class_stats(struct
 
 	cl_q = q->queues[cl - 1];
 	if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
-				  d, NULL, &cl_q->bstats) < 0 ||
+				  d, cl_q->cpu_bstats, &cl_q->bstats) < 0 ||
 	    qdisc_qstats_copy(d, cl_q) < 0)
 		return -1;