[NET_SCHED]: Avoid requeue warning on dev_deactivate (41a23b07) · Commits · 戴 / test

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:

Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by:

David S. Miller <davem@davemloft.net>

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)

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