1 files changed, 38 insertions, 10 deletions

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index a64132a5db36..531fac1d2875 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -901,7 +901,7 @@ struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
 	if (!ops->init || ops->init(sch, NULL, extack) == 0)
 		return sch;
 
-	qdisc_destroy(sch);
+	qdisc_put(sch);
 	return NULL;
 }
 EXPORT_SYMBOL(qdisc_create_dflt);
@@ -941,15 +941,18 @@ void qdisc_free(struct Qdisc *qdisc)
 	kfree((char *) qdisc - qdisc->padded);
 }
 
-void qdisc_destroy(struct Qdisc *qdisc)
+void qdisc_free_cb(struct rcu_head *head)
+{
+	struct Qdisc *q = container_of(head, struct Qdisc, rcu);
+
+	qdisc_free(q);
+}
+
+static void qdisc_destroy(struct Qdisc *qdisc)
 {
 	const struct Qdisc_ops  *ops = qdisc->ops;
 	struct sk_buff *skb, *tmp;
 
-	if (qdisc->flags & TCQ_F_BUILTIN ||
-	    !refcount_dec_and_test(&qdisc->refcnt))
-		return;
-
 #ifdef CONFIG_NET_SCHED
 	qdisc_hash_del(qdisc);
 
@@ -974,9 +977,34 @@ void qdisc_destroy(struct Qdisc *qdisc)
 		kfree_skb_list(skb);
 	}
 
-	qdisc_free(qdisc);
+	call_rcu(&qdisc->rcu, qdisc_free_cb);
+}
+
+void qdisc_put(struct Qdisc *qdisc)
+{
+	if (qdisc->flags & TCQ_F_BUILTIN ||
+	    !refcount_dec_and_test(&qdisc->refcnt))
+		return;
+
+	qdisc_destroy(qdisc);
+}
+EXPORT_SYMBOL(qdisc_put);
+
+/* Version of qdisc_put() that is called with rtnl mutex unlocked.
+ * Intended to be used as optimization, this function only takes rtnl lock if
+ * qdisc reference counter reached zero.
+ */
+
+void qdisc_put_unlocked(struct Qdisc *qdisc)
+{
+	if (qdisc->flags & TCQ_F_BUILTIN ||
+	    !refcount_dec_and_rtnl_lock(&qdisc->refcnt))
+		return;
+
+	qdisc_destroy(qdisc);
+	rtnl_unlock();
 }
-EXPORT_SYMBOL(qdisc_destroy);
+EXPORT_SYMBOL(qdisc_put_unlocked);
 
 /* Attach toplevel qdisc to device queue. */
 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
@@ -1270,7 +1298,7 @@ static void shutdown_scheduler_queue(struct net_device *dev,
 		rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
 		dev_queue->qdisc_sleeping = qdisc_default;
 
-		qdisc_destroy(qdisc);
+		qdisc_put(qdisc);
 	}
 }
 
@@ -1279,7 +1307,7 @@ void dev_shutdown(struct net_device *dev)
 	netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
 	if (dev_ingress_queue(dev))
 		shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
-	qdisc_destroy(dev->qdisc);
+	qdisc_put(dev->qdisc);
 	dev->qdisc = &noop_qdisc;
 
 	WARN_ON(timer_pending(&dev->watchdog_timer));