2 * net/sched/sch_generic.c Generic packet scheduler routines.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 * Jamal Hadi Salim, <hadi@cyberus.ca> 990601
14 #include <linux/bitops.h>
15 #include <linux/module.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/sched.h>
19 #include <linux/string.h>
20 #include <linux/errno.h>
21 #include <linux/netdevice.h>
22 #include <linux/skbuff.h>
23 #include <linux/rtnetlink.h>
24 #include <linux/init.h>
25 #include <linux/rcupdate.h>
26 #include <linux/list.h>
27 #include <linux/slab.h>
28 #include <net/pkt_sched.h>
31 /* Main transmission queue. */
33 /* Modifications to data participating in scheduling must be protected with
34 * qdisc_lock(qdisc) spinlock.
36 * The idea is the following:
37 * - enqueue, dequeue are serialized via qdisc root lock
38 * - ingress filtering is also serialized via qdisc root lock
39 * - updates to tree and tree walking are only done under the rtnl mutex.
42 static inline int dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
47 q->q.qlen++; /* it's still part of the queue */
53 static inline struct sk_buff *dequeue_skb(struct Qdisc *q)
55 struct sk_buff *skb = q->gso_skb;
58 struct net_device *dev = qdisc_dev(q);
59 struct netdev_queue *txq;
61 /* check the reason of requeuing without tx lock first */
62 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
63 if (!netif_tx_queue_frozen_or_stopped(txq)) {
75 static inline int handle_dev_cpu_collision(struct sk_buff *skb,
76 struct netdev_queue *dev_queue,
81 if (unlikely(dev_queue->xmit_lock_owner == smp_processor_id())) {
83 * Same CPU holding the lock. It may be a transient
84 * configuration error, when hard_start_xmit() recurses. We
85 * detect it by checking xmit owner and drop the packet when
86 * deadloop is detected. Return OK to try the next skb.
90 pr_warning("Dead loop on netdevice %s, fix it urgently!\n",
91 dev_queue->dev->name);
95 * Another cpu is holding lock, requeue & delay xmits for
98 __this_cpu_inc(softnet_data.cpu_collision);
99 ret = dev_requeue_skb(skb, q);
106 * Transmit one skb, and handle the return status as required. Holding the
107 * __QDISC_STATE_RUNNING bit guarantees that only one CPU can execute this
110 * Returns to the caller:
111 * 0 - queue is empty or throttled.
112 * >0 - queue is not empty.
114 int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
115 struct net_device *dev, struct netdev_queue *txq,
116 spinlock_t *root_lock)
118 int ret = NETDEV_TX_BUSY;
120 /* And release qdisc */
121 spin_unlock(root_lock);
123 HARD_TX_LOCK(dev, txq, smp_processor_id());
124 if (!netif_tx_queue_frozen_or_stopped(txq))
125 ret = dev_hard_start_xmit(skb, dev, txq);
127 HARD_TX_UNLOCK(dev, txq);
129 spin_lock(root_lock);
131 if (dev_xmit_complete(ret)) {
132 /* Driver sent out skb successfully or skb was consumed */
134 } else if (ret == NETDEV_TX_LOCKED) {
135 /* Driver try lock failed */
136 ret = handle_dev_cpu_collision(skb, txq, q);
138 /* Driver returned NETDEV_TX_BUSY - requeue skb */
139 if (unlikely (ret != NETDEV_TX_BUSY && net_ratelimit()))
140 pr_warning("BUG %s code %d qlen %d\n",
141 dev->name, ret, q->q.qlen);
143 ret = dev_requeue_skb(skb, q);
146 if (ret && netif_tx_queue_frozen_or_stopped(txq))
153 * NOTE: Called under qdisc_lock(q) with locally disabled BH.
155 * __QDISC_STATE_RUNNING guarantees only one CPU can process
156 * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
159 * netif_tx_lock serializes accesses to device driver.
161 * qdisc_lock(q) and netif_tx_lock are mutually exclusive,
162 * if one is grabbed, another must be free.
164 * Note, that this procedure can be called by a watchdog timer
166 * Returns to the caller:
167 * 0 - queue is empty or throttled.
168 * >0 - queue is not empty.
171 static inline int qdisc_restart(struct Qdisc *q)
173 struct netdev_queue *txq;
174 struct net_device *dev;
175 spinlock_t *root_lock;
179 skb = dequeue_skb(q);
182 WARN_ON_ONCE(skb_dst_is_noref(skb));
183 root_lock = qdisc_lock(q);
185 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
187 return sch_direct_xmit(skb, q, dev, txq, root_lock);
190 void __qdisc_run(struct Qdisc *q)
192 unsigned long start_time = jiffies;
194 while (qdisc_restart(q)) {
196 * Postpone processing if
197 * 1. another process needs the CPU;
198 * 2. we've been doing it for too long.
200 if (need_resched() || jiffies != start_time) {
209 unsigned long dev_trans_start(struct net_device *dev)
211 unsigned long val, res = dev->trans_start;
214 for (i = 0; i < dev->num_tx_queues; i++) {
215 val = netdev_get_tx_queue(dev, i)->trans_start;
216 if (val && time_after(val, res))
219 dev->trans_start = res;
222 EXPORT_SYMBOL(dev_trans_start);
224 static void dev_watchdog(unsigned long arg)
226 struct net_device *dev = (struct net_device *)arg;
229 if (!qdisc_tx_is_noop(dev)) {
230 if (netif_device_present(dev) &&
231 netif_running(dev) &&
232 netif_carrier_ok(dev)) {
233 int some_queue_timedout = 0;
235 unsigned long trans_start;
237 for (i = 0; i < dev->num_tx_queues; i++) {
238 struct netdev_queue *txq;
240 txq = netdev_get_tx_queue(dev, i);
242 * old device drivers set dev->trans_start
244 trans_start = txq->trans_start ? : dev->trans_start;
245 if (netif_tx_queue_stopped(txq) &&
246 time_after(jiffies, (trans_start +
247 dev->watchdog_timeo))) {
248 some_queue_timedout = 1;
253 if (some_queue_timedout) {
255 WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",
256 dev->name, netdev_drivername(dev, drivername, 64), i);
257 dev->netdev_ops->ndo_tx_timeout(dev);
259 if (!mod_timer(&dev->watchdog_timer,
260 round_jiffies(jiffies +
261 dev->watchdog_timeo)))
265 netif_tx_unlock(dev);
270 void __netdev_watchdog_up(struct net_device *dev)
272 if (dev->netdev_ops->ndo_tx_timeout) {
273 if (dev->watchdog_timeo <= 0)
274 dev->watchdog_timeo = 5*HZ;
275 if (!mod_timer(&dev->watchdog_timer,
276 round_jiffies(jiffies + dev->watchdog_timeo)))
281 static void dev_watchdog_up(struct net_device *dev)
283 __netdev_watchdog_up(dev);
286 static void dev_watchdog_down(struct net_device *dev)
288 netif_tx_lock_bh(dev);
289 if (del_timer(&dev->watchdog_timer))
291 netif_tx_unlock_bh(dev);
295 * netif_carrier_on - set carrier
296 * @dev: network device
298 * Device has detected that carrier.
300 void netif_carrier_on(struct net_device *dev)
302 if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
303 if (dev->reg_state == NETREG_UNINITIALIZED)
305 linkwatch_fire_event(dev);
306 if (netif_running(dev))
307 __netdev_watchdog_up(dev);
310 EXPORT_SYMBOL(netif_carrier_on);
313 * netif_carrier_off - clear carrier
314 * @dev: network device
316 * Device has detected loss of carrier.
318 void netif_carrier_off(struct net_device *dev)
320 if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
321 if (dev->reg_state == NETREG_UNINITIALIZED)
323 linkwatch_fire_event(dev);
326 EXPORT_SYMBOL(netif_carrier_off);
329 * netif_notify_peers - notify network peers about existence of @dev
330 * @dev: network device
332 * Generate traffic such that interested network peers are aware of
333 * @dev, such as by generating a gratuitous ARP. This may be used when
334 * a device wants to inform the rest of the network about some sort of
335 * reconfiguration such as a failover event or virtual machine
338 void netif_notify_peers(struct net_device *dev)
341 call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, dev);
344 EXPORT_SYMBOL(netif_notify_peers);
346 /* "NOOP" scheduler: the best scheduler, recommended for all interfaces
347 under all circumstances. It is difficult to invent anything faster or
351 static int noop_enqueue(struct sk_buff *skb, struct Qdisc * qdisc)
357 static struct sk_buff *noop_dequeue(struct Qdisc * qdisc)
362 struct Qdisc_ops noop_qdisc_ops __read_mostly = {
365 .enqueue = noop_enqueue,
366 .dequeue = noop_dequeue,
367 .peek = noop_dequeue,
368 .owner = THIS_MODULE,
371 static struct netdev_queue noop_netdev_queue = {
372 .qdisc = &noop_qdisc,
373 .qdisc_sleeping = &noop_qdisc,
376 struct Qdisc noop_qdisc = {
377 .enqueue = noop_enqueue,
378 .dequeue = noop_dequeue,
379 .flags = TCQ_F_BUILTIN,
380 .ops = &noop_qdisc_ops,
381 .list = LIST_HEAD_INIT(noop_qdisc.list),
382 .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
383 .dev_queue = &noop_netdev_queue,
384 .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
386 EXPORT_SYMBOL(noop_qdisc);
388 static struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
391 .enqueue = noop_enqueue,
392 .dequeue = noop_dequeue,
393 .peek = noop_dequeue,
394 .owner = THIS_MODULE,
397 static struct Qdisc noqueue_qdisc;
398 static struct netdev_queue noqueue_netdev_queue = {
399 .qdisc = &noqueue_qdisc,
400 .qdisc_sleeping = &noqueue_qdisc,
403 static struct Qdisc noqueue_qdisc = {
405 .dequeue = noop_dequeue,
406 .flags = TCQ_F_BUILTIN,
407 .ops = &noqueue_qdisc_ops,
408 .list = LIST_HEAD_INIT(noqueue_qdisc.list),
409 .q.lock = __SPIN_LOCK_UNLOCKED(noqueue_qdisc.q.lock),
410 .dev_queue = &noqueue_netdev_queue,
411 .busylock = __SPIN_LOCK_UNLOCKED(noqueue_qdisc.busylock),
415 static const u8 prio2band[TC_PRIO_MAX + 1] = {
416 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1
419 /* 3-band FIFO queue: old style, but should be a bit faster than
420 generic prio+fifo combination.
423 #define PFIFO_FAST_BANDS 3
426 * Private data for a pfifo_fast scheduler containing:
427 * - queues for the three band
428 * - bitmap indicating which of the bands contain skbs
430 struct pfifo_fast_priv {
432 struct sk_buff_head q[PFIFO_FAST_BANDS];
436 * Convert a bitmap to the first band number where an skb is queued, where:
437 * bitmap=0 means there are no skbs on any band.
438 * bitmap=1 means there is an skb on band 0.
439 * bitmap=7 means there are skbs on all 3 bands, etc.
441 static const int bitmap2band[] = {-1, 0, 1, 0, 2, 0, 1, 0};
443 static inline struct sk_buff_head *band2list(struct pfifo_fast_priv *priv,
446 return priv->q + band;
449 static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc)
451 if (skb_queue_len(&qdisc->q) < qdisc_dev(qdisc)->tx_queue_len) {
452 int band = prio2band[skb->priority & TC_PRIO_MAX];
453 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
454 struct sk_buff_head *list = band2list(priv, band);
456 priv->bitmap |= (1 << band);
458 return __qdisc_enqueue_tail(skb, qdisc, list);
461 return qdisc_drop(skb, qdisc);
464 static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
466 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
467 int band = bitmap2band[priv->bitmap];
469 if (likely(band >= 0)) {
470 struct sk_buff_head *list = band2list(priv, band);
471 struct sk_buff *skb = __qdisc_dequeue_head(qdisc, list);
474 if (skb_queue_empty(list))
475 priv->bitmap &= ~(1 << band);
483 static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
485 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
486 int band = bitmap2band[priv->bitmap];
489 struct sk_buff_head *list = band2list(priv, band);
491 return skb_peek(list);
497 static void pfifo_fast_reset(struct Qdisc *qdisc)
500 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
502 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
503 __qdisc_reset_queue(qdisc, band2list(priv, prio));
506 qdisc->qstats.backlog = 0;
510 static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
512 struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
514 memcpy(&opt.priomap, prio2band, TC_PRIO_MAX + 1);
515 NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
522 static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt)
525 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
527 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
528 skb_queue_head_init(band2list(priv, prio));
533 struct Qdisc_ops pfifo_fast_ops __read_mostly = {
535 .priv_size = sizeof(struct pfifo_fast_priv),
536 .enqueue = pfifo_fast_enqueue,
537 .dequeue = pfifo_fast_dequeue,
538 .peek = pfifo_fast_peek,
539 .init = pfifo_fast_init,
540 .reset = pfifo_fast_reset,
541 .dump = pfifo_fast_dump,
542 .owner = THIS_MODULE,
544 EXPORT_SYMBOL(pfifo_fast_ops);
546 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
547 struct Qdisc_ops *ops)
554 /* ensure that the Qdisc and the private data are 64-byte aligned */
555 size = QDISC_ALIGN(sizeof(*sch));
556 size += ops->priv_size + (QDISC_ALIGNTO - 1);
558 p = kzalloc_node(size, GFP_KERNEL,
559 netdev_queue_numa_node_read(dev_queue));
563 sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
564 sch->padded = (char *) sch - (char *) p;
566 INIT_LIST_HEAD(&sch->list);
567 skb_queue_head_init(&sch->q);
568 spin_lock_init(&sch->busylock);
570 sch->enqueue = ops->enqueue;
571 sch->dequeue = ops->dequeue;
572 sch->dev_queue = dev_queue;
573 dev_hold(qdisc_dev(sch));
574 atomic_set(&sch->refcnt, 1);
581 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
582 struct Qdisc_ops *ops, unsigned int parentid)
586 sch = qdisc_alloc(dev_queue, ops);
589 sch->parent = parentid;
591 if (!ops->init || ops->init(sch, NULL) == 0)
598 EXPORT_SYMBOL(qdisc_create_dflt);
600 /* Under qdisc_lock(qdisc) and BH! */
602 void qdisc_reset(struct Qdisc *qdisc)
604 const struct Qdisc_ops *ops = qdisc->ops;
609 if (qdisc->gso_skb) {
610 kfree_skb(qdisc->gso_skb);
611 qdisc->gso_skb = NULL;
615 EXPORT_SYMBOL(qdisc_reset);
617 static void qdisc_rcu_free(struct rcu_head *head)
619 struct Qdisc *qdisc = container_of(head, struct Qdisc, rcu_head);
621 kfree((char *) qdisc - qdisc->padded);
624 void qdisc_destroy(struct Qdisc *qdisc)
626 const struct Qdisc_ops *ops = qdisc->ops;
628 if (qdisc->flags & TCQ_F_BUILTIN ||
629 !atomic_dec_and_test(&qdisc->refcnt))
632 #ifdef CONFIG_NET_SCHED
633 qdisc_list_del(qdisc);
635 qdisc_put_stab(qdisc->stab);
637 gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est);
643 module_put(ops->owner);
644 dev_put(qdisc_dev(qdisc));
646 kfree_skb(qdisc->gso_skb);
648 * gen_estimator est_timer() might access qdisc->q.lock,
649 * wait a RCU grace period before freeing qdisc.
651 call_rcu(&qdisc->rcu_head, qdisc_rcu_free);
653 EXPORT_SYMBOL(qdisc_destroy);
655 /* Attach toplevel qdisc to device queue. */
656 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
659 struct Qdisc *oqdisc = dev_queue->qdisc_sleeping;
660 spinlock_t *root_lock;
662 root_lock = qdisc_lock(oqdisc);
663 spin_lock_bh(root_lock);
665 /* Prune old scheduler */
666 if (oqdisc && atomic_read(&oqdisc->refcnt) <= 1)
669 /* ... and graft new one */
672 dev_queue->qdisc_sleeping = qdisc;
673 rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
675 spin_unlock_bh(root_lock);
679 EXPORT_SYMBOL(dev_graft_qdisc);
681 static void attach_one_default_qdisc(struct net_device *dev,
682 struct netdev_queue *dev_queue,
685 struct Qdisc *qdisc = &noqueue_qdisc;
687 if (dev->tx_queue_len) {
688 qdisc = qdisc_create_dflt(dev_queue,
689 &pfifo_fast_ops, TC_H_ROOT);
691 netdev_info(dev, "activation failed\n");
695 /* Can by-pass the queue discipline for default qdisc */
696 qdisc->flags |= TCQ_F_CAN_BYPASS;
698 dev_queue->qdisc_sleeping = qdisc;
701 static void attach_default_qdiscs(struct net_device *dev)
703 struct netdev_queue *txq;
706 txq = netdev_get_tx_queue(dev, 0);
708 if (!netif_is_multiqueue(dev) || dev->tx_queue_len == 0) {
709 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
710 dev->qdisc = txq->qdisc_sleeping;
711 atomic_inc(&dev->qdisc->refcnt);
713 qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT);
715 qdisc->ops->attach(qdisc);
721 static void transition_one_qdisc(struct net_device *dev,
722 struct netdev_queue *dev_queue,
723 void *_need_watchdog)
725 struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
726 int *need_watchdog_p = _need_watchdog;
728 if (!(new_qdisc->flags & TCQ_F_BUILTIN))
729 clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
731 rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
732 if (need_watchdog_p && new_qdisc != &noqueue_qdisc) {
733 dev_queue->trans_start = 0;
734 *need_watchdog_p = 1;
738 void dev_activate(struct net_device *dev)
742 /* No queueing discipline is attached to device;
743 create default one i.e. pfifo_fast for devices,
744 which need queueing and noqueue_qdisc for
748 if (dev->qdisc == &noop_qdisc)
749 attach_default_qdiscs(dev);
751 if (!netif_carrier_ok(dev))
752 /* Delay activation until next carrier-on event */
756 netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
757 if (dev_ingress_queue(dev))
758 transition_one_qdisc(dev, dev_ingress_queue(dev), NULL);
761 dev->trans_start = jiffies;
762 dev_watchdog_up(dev);
765 EXPORT_SYMBOL(dev_activate);
767 static void dev_deactivate_queue(struct net_device *dev,
768 struct netdev_queue *dev_queue,
769 void *_qdisc_default)
771 struct Qdisc *qdisc_default = _qdisc_default;
774 qdisc = dev_queue->qdisc;
776 spin_lock_bh(qdisc_lock(qdisc));
778 if (!(qdisc->flags & TCQ_F_BUILTIN))
779 set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
781 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
784 spin_unlock_bh(qdisc_lock(qdisc));
788 static bool some_qdisc_is_busy(struct net_device *dev)
792 for (i = 0; i < dev->num_tx_queues; i++) {
793 struct netdev_queue *dev_queue;
794 spinlock_t *root_lock;
798 dev_queue = netdev_get_tx_queue(dev, i);
799 q = dev_queue->qdisc_sleeping;
800 root_lock = qdisc_lock(q);
802 spin_lock_bh(root_lock);
804 val = (qdisc_is_running(q) ||
805 test_bit(__QDISC_STATE_SCHED, &q->state));
807 spin_unlock_bh(root_lock);
815 void dev_deactivate_many(struct list_head *head)
817 struct net_device *dev;
819 list_for_each_entry(dev, head, unreg_list) {
820 netdev_for_each_tx_queue(dev, dev_deactivate_queue,
822 if (dev_ingress_queue(dev))
823 dev_deactivate_queue(dev, dev_ingress_queue(dev),
826 dev_watchdog_down(dev);
829 /* Wait for outstanding qdisc-less dev_queue_xmit calls. */
832 /* Wait for outstanding qdisc_run calls. */
833 list_for_each_entry(dev, head, unreg_list)
834 while (some_qdisc_is_busy(dev))
838 void dev_deactivate(struct net_device *dev)
842 list_add(&dev->unreg_list, &single);
843 dev_deactivate_many(&single);
845 EXPORT_SYMBOL(dev_deactivate);
847 static void dev_init_scheduler_queue(struct net_device *dev,
848 struct netdev_queue *dev_queue,
851 struct Qdisc *qdisc = _qdisc;
853 dev_queue->qdisc = qdisc;
854 dev_queue->qdisc_sleeping = qdisc;
857 void dev_init_scheduler(struct net_device *dev)
859 dev->qdisc = &noop_qdisc;
860 netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
861 if (dev_ingress_queue(dev))
862 dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
864 setup_timer(&dev->watchdog_timer, dev_watchdog, (unsigned long)dev);
867 static void shutdown_scheduler_queue(struct net_device *dev,
868 struct netdev_queue *dev_queue,
869 void *_qdisc_default)
871 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
872 struct Qdisc *qdisc_default = _qdisc_default;
875 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
876 dev_queue->qdisc_sleeping = qdisc_default;
878 qdisc_destroy(qdisc);
882 void dev_shutdown(struct net_device *dev)
884 netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
885 if (dev_ingress_queue(dev))
886 shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
887 qdisc_destroy(dev->qdisc);
888 dev->qdisc = &noop_qdisc;
890 WARN_ON(timer_pending(&dev->watchdog_timer));