Merge branch 'net-sched-fix-stats-accounting-for-child-NOLOCK-qdiscs'

Paolo Abeni says:

====================
net: sched: fix stats accounting for child NOLOCK qdiscs

Currently, stats accounting for NOLOCK qdisc enslaved to classful (lock)
qdiscs is buggy. Per CPU values are ignored in most places, as a result,
stats dump in the above scenario always report 0 length backlog and parent
backlog len is not updated correctly on NOLOCK qdisc removal.

The first patch address stats dumping, and the second one child qdisc removal.
I'm targeting the net tree as this is a bugfix, but it could be moved to
net-next due to the relatively large diffstat.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 14 deletions

diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 24cc220a3218..d2ab463f22ae 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -845,16 +845,6 @@ qdisc_peek_len(struct Qdisc *sch)
 }
 
 static void
-hfsc_purge_queue(struct Qdisc *sch, struct hfsc_class *cl)
-{
-	unsigned int len = cl->qdisc->q.qlen;
-	unsigned int backlog = cl->qdisc->qstats.backlog;
-
-	qdisc_reset(cl->qdisc);
-	qdisc_tree_reduce_backlog(cl->qdisc, len, backlog);
-}
-
-static void
 hfsc_adjust_levels(struct hfsc_class *cl)
 {
 	struct hfsc_class *p;
@@ -1076,7 +1066,7 @@ hfsc_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
 	qdisc_class_hash_insert(&q->clhash, &cl->cl_common);
 	list_add_tail(&cl->siblings, &parent->children);
 	if (parent->level == 0)
-		hfsc_purge_queue(sch, parent);
+		qdisc_purge_queue(parent->qdisc);
 	hfsc_adjust_levels(parent);
 	sch_tree_unlock(sch);
 
@@ -1112,7 +1102,7 @@ hfsc_delete_class(struct Qdisc *sch, unsigned long arg)
 	list_del(&cl->siblings);
 	hfsc_adjust_levels(cl->cl_parent);
 
-	hfsc_purge_queue(sch, cl);
+	qdisc_purge_queue(cl->qdisc);
 	qdisc_class_hash_remove(&q->clhash, &cl->cl_common);
 
 	sch_tree_unlock(sch);
@@ -1328,8 +1318,9 @@ hfsc_dump_class_stats(struct Qdisc *sch, unsigned long arg,
 {
 	struct hfsc_class *cl = (struct hfsc_class *)arg;
 	struct tc_hfsc_stats xstats;
+	__u32 qlen;
 
-	cl->qstats.backlog = cl->qdisc->qstats.backlog;
+	qdisc_qstats_qlen_backlog(cl->qdisc, &qlen, &cl->qstats.backlog);
 	xstats.level   = cl->level;
 	xstats.period  = cl->cl_vtperiod;
 	xstats.work    = cl->cl_total;
@@ -1337,7 +1328,7 @@ hfsc_dump_class_stats(struct Qdisc *sch, unsigned long arg,
 
 	if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch), d, NULL, &cl->bstats) < 0 ||
 	    gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
-	    gnet_stats_copy_queue(d, NULL, &cl->qstats, cl->qdisc->q.qlen) < 0)
+	    gnet_stats_copy_queue(d, NULL, &cl->qstats, qlen) < 0)
 		return -1;
 
 	return gnet_stats_copy_app(d, &xstats, sizeof(xstats));