[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, 8 insertions, 3 deletions

diff --git a/net/sched/sch_prio.c b/net/sched/sch_prio.c
index 3fc0c0fa5bcc..2567b4c96c1e 100644
--- a/net/sched/sch_prio.c
+++ b/net/sched/sch_prio.c
@@ -222,8 +222,10 @@ static int prio_tune(struct Qdisc *sch, struct rtattr *opt)
 
         for (i=q->bands; i<TCQ_PRIO_BANDS; i++) {
                 struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
-                if (child != &noop_qdisc)
+                if (child != &noop_qdisc) {
+                        qdisc_tree_decrease_qlen(child, child->q.qlen);
                         qdisc_destroy(child);
+                }
         }
         sch_tree_unlock(sch);
 
@@ -236,8 +238,11 @@ static int prio_tune(struct Qdisc *sch, struct rtattr *opt)
                                 sch_tree_lock(sch);
                                 child = xchg(&q->queues[i], child);
 
-                                if (child != &noop_qdisc)
+                                if (child != &noop_qdisc) {
+                                        qdisc_tree_decrease_qlen(child,
+                                                                 child->q.qlen);
                                         qdisc_destroy(child);
+                                }
                                 sch_tree_unlock(sch);
                         }
                 }
@@ -295,7 +300,7 @@ static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
         sch_tree_lock(sch);
         *old = q->queues[band];
         q->queues[band] = new;
-        sch->q.qlen -= (*old)->q.qlen;
+        qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
         qdisc_reset(*old);
         sch_tree_unlock(sch);