pkt_sched: Use rcu_assign_pointer() to change dev_queue->qdisc

These pointers are RCU protected, so proper primitives should be used.
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sched/sch_api.c

@@ -635,7 +635,7 @@ static struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
 	if (qdisc == NULL)
 		qdisc = &noop_qdisc;
 	dev_queue->qdisc_sleeping = qdisc;
-	dev_queue->qdisc = &noop_qdisc;
+	rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
 
 	spin_unlock_bh(root_lock);
 

net/sched/sch_generic.c

@@ -634,7 +634,7 @@ static void dev_deactivate_queue(struct net_device *dev,
 		if (!(qdisc->flags & TCQ_F_BUILTIN))
 			set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
 
-		dev_queue->qdisc = qdisc_default;
+		rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
 		qdisc_reset(qdisc);
 
 		spin_unlock_bh(qdisc_lock(qdisc));
@@ -709,7 +709,7 @@ static void shutdown_scheduler_queue(struct net_device *dev,
 	struct Qdisc *qdisc_default = _qdisc_default;
 
 	if (qdisc) {
-		dev_queue->qdisc = qdisc_default;
+		rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
 		dev_queue->qdisc_sleeping = qdisc_default;
 
 		qdisc_destroy(qdisc);