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Commit 41a23b07 authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
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[NET_SCHED]: Avoid requeue warning on dev_deactivate 



When we relinquish queue_lock in qdisc_restart and then retake it for
requeueing, we might race against dev_deactivate and end up requeueing
onto noop_qdisc.  This causes a warning to be printed.

This patch fixes this by checking this before we requeue.  As an added
bonus, we can remove the same check in __qdisc_run which was added to
prevent dev->gso_skb from being requeued when we're shutting down.

Even though we've had to add a new conditional in its place, it's better
because it only happens on requeues rather than every single time that
qdisc_run is called.

For this to work we also need to move the clearing of gso_skb up in
dev_deactivate as now qdisc_restart can occur even after we wait for
__LINK_STATE_QDISC_RUNNING to clear (but it won't do anything as long
as the queue and gso_skb is already clear).

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cce1fa36

net/sched/sch_generic.c

+8 −10
Original line number Diff line number Diff line
@@ -162,7 +162,9 @@ static inline int qdisc_restart(struct net_device *dev) 
		 */



requeue:

		if (skb->next)

		if (unlikely(q == &noop_qdisc))

			kfree_skb(skb);

		else if (skb->next)

			dev->gso_skb = skb;

		else

			q->ops->requeue(skb, q);
@@ -177,15 +179,11 @@ out: 


void __qdisc_run(struct net_device *dev)

{

	if (unlikely(dev->qdisc == &noop_qdisc))

		goto out;



	do {

		if (!qdisc_restart(dev))

			break;

	} while (!netif_queue_stopped(dev));



out:

	clear_bit(__LINK_STATE_QDISC_RUNNING, &dev->state);

}
@@ -547,6 +545,7 @@ void dev_activate(struct net_device *dev) 
void dev_deactivate(struct net_device *dev)

{

	struct Qdisc *qdisc;

	struct sk_buff *skb;



	spin_lock_bh(&dev->queue_lock);

	qdisc = dev->qdisc;
@@ -554,8 +553,12 @@ void dev_deactivate(struct net_device *dev) 


	qdisc_reset(qdisc);



	skb = dev->gso_skb;

	dev->gso_skb = NULL;

	spin_unlock_bh(&dev->queue_lock);



	kfree_skb(skb);



	dev_watchdog_down(dev);



	/* Wait for outstanding dev_queue_xmit calls. */
@@ -564,11 +567,6 @@ void dev_deactivate(struct net_device *dev) 
	/* Wait for outstanding qdisc_run calls. */

	while (test_bit(__LINK_STATE_QDISC_RUNNING, &dev->state))

		yield();



	if (dev->gso_skb) {

		kfree_skb(dev->gso_skb);

		dev->gso_skb = NULL;

	}

}



void dev_init_scheduler(struct net_device *dev)