[NET_SCHED]: Fix endless loops (part 2): "simple" qdiscs

Convert the "simple" qdiscs to use qdisc_tree_decrease_qlen() where
necessary:

- all graft operations
- destruction of old child qdiscs in prio, red and tbf change operation
- purging of queue in sfq change operation

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 2 deletions

diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index 2562a6040b76..23b7624354f5 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -348,8 +348,10 @@ static int tbf_change(struct Qdisc* sch, struct rtattr *opt)
 	}
 
 	sch_tree_lock(sch);
-	if (child)
+	if (child) {
+		qdisc_tree_decrease_qlen(q->qdisc, q->qdisc->q.qlen);
 		qdisc_destroy(xchg(&q->qdisc, child));
+	}
 	q->limit = qopt->limit;
 	q->mtu = qopt->mtu;
 	q->max_size = max_size;
@@ -451,8 +453,8 @@ static int tbf_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 
 	sch_tree_lock(sch);
 	*old = xchg(&q->qdisc, new);
+	qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
 	qdisc_reset(*old);
-	sch->q.qlen = 0;
 	sch_tree_unlock(sch);
 
 	return 0;