3 files changed, 49 insertions, 8 deletions

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index ef0efeca635..e7fb9e0d21b 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -199,19 +199,53 @@ struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle)
 	return NULL;
 }
 
+/*
+ * This lock is needed until some qdiscs stop calling qdisc_tree_decrease_qlen()
+ * without rtnl_lock(); currently hfsc_dequeue(), netem_dequeue(), tbf_dequeue()
+ */
+static DEFINE_SPINLOCK(qdisc_list_lock);
+
+static void qdisc_list_add(struct Qdisc *q)
+{
+	if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
+		spin_lock_bh(&qdisc_list_lock);
+		list_add_tail(&q->list, &qdisc_root_sleeping(q)->list);
+		spin_unlock_bh(&qdisc_list_lock);
+	}
+}
+
+void qdisc_list_del(struct Qdisc *q)
+{
+	if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
+		spin_lock_bh(&qdisc_list_lock);
+		list_del(&q->list);
+		spin_unlock_bh(&qdisc_list_lock);
+	}
+}
+EXPORT_SYMBOL(qdisc_list_del);
+
 struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle)
 {
 	unsigned int i;
+	struct Qdisc *q;
+
+	spin_lock_bh(&qdisc_list_lock);
 
 	for (i = 0; i < dev->num_tx_queues; i++) {
 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
-		struct Qdisc *q, *txq_root = txq->qdisc_sleeping;
+		struct Qdisc *txq_root = txq->qdisc_sleeping;
 
 		q = qdisc_match_from_root(txq_root, handle);
 		if (q)
-			return q;
+			goto unlock;
 	}
-	return qdisc_match_from_root(dev->rx_queue.qdisc_sleeping, handle);
+
+	q = qdisc_match_from_root(dev->rx_queue.qdisc_sleeping, handle);
+
+unlock:
+	spin_unlock_bh(&qdisc_list_lock);
+
+	return q;
 }
 
 static struct Qdisc *qdisc_leaf(struct Qdisc *p, u32 classid)
@@ -444,6 +478,10 @@ void qdisc_watchdog_schedule(struct qdisc_watchdog *wd, psched_time_t expires)
 {
 	ktime_t time;
 
+	if (test_bit(__QDISC_STATE_DEACTIVATED,
+		     &qdisc_root_sleeping(wd->qdisc)->state))
+		return;
+
 	wd->qdisc->flags |= TCQ_F_THROTTLED;
 	time = ktime_set(0, 0);
 	time = ktime_add_ns(time, PSCHED_US2NS(expires));
@@ -806,8 +844,8 @@ qdisc_create(struct net_device *dev, struct netdev_queue *dev_queue,
 				goto err_out3;
 			}
 		}
-		if ((parent != TC_H_ROOT) && !(sch->flags & TCQ_F_INGRESS))
-			list_add_tail(&sch->list, &dev_queue->qdisc_sleeping->list);
+
+		qdisc_list_add(sch);
 
 		return sch;
 	}
diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index 47ef492c4ff..8fa90d68ec6 100644
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -521,6 +521,10 @@ static void cbq_ovl_delay(struct cbq_class *cl)
 	struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
 	psched_tdiff_t delay = cl->undertime - q->now;
 
+	if (test_bit(__QDISC_STATE_DEACTIVATED,
+		     &qdisc_root_sleeping(cl->qdisc)->state))
+		return;
+
 	if (!cl->delayed) {
 		psched_time_t sched = q->now;
 		ktime_t expires;
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index c3ed4d44fc1..5f0ade7806a 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -526,10 +526,9 @@ void qdisc_destroy(struct Qdisc *qdisc)
 	    !atomic_dec_and_test(&qdisc->refcnt))
 		return;
 
-	if (qdisc->parent)
-		list_del(&qdisc->list);
-
 #ifdef CONFIG_NET_SCHED
+	qdisc_list_del(qdisc);
+
 	qdisc_put_stab(qdisc->stab);
 #endif
 	gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est);