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 <linux/if_vlan.h>
29 #include <net/sch_generic.h>
30 #include <net/pkt_sched.h>
33 /* Qdisc to use by default */
34 const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops;
35 EXPORT_SYMBOL(default_qdisc_ops);
37 /* Main transmission queue. */
39 /* Modifications to data participating in scheduling must be protected with
40 * qdisc_lock(qdisc) spinlock.
42 * The idea is the following:
43 * - enqueue, dequeue are serialized via qdisc root lock
44 * - ingress filtering is also serialized via qdisc root lock
45 * - updates to tree and tree walking are only done under the rtnl mutex.
48 static inline int dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
52 q->q.qlen++; /* it's still part of the queue */
58 static void try_bulk_dequeue_skb(struct Qdisc *q,
60 const struct netdev_queue *txq)
62 int bytelimit = qdisc_avail_bulklimit(txq) - skb->len;
64 while (bytelimit > 0) {
65 struct sk_buff *nskb = q->dequeue(q);
70 bytelimit -= nskb->len; /* covers GSO len */
77 /* Note that dequeue_skb can possibly return a SKB list (via skb->next).
78 * A requeued skb (via q->gso_skb) can also be a SKB list.
80 static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate)
82 struct sk_buff *skb = q->gso_skb;
83 const struct netdev_queue *txq = q->dev_queue;
87 /* check the reason of requeuing without tx lock first */
88 txq = skb_get_tx_queue(txq->dev, skb);
89 if (!netif_xmit_frozen_or_stopped(txq)) {
94 /* skb in gso_skb were already validated */
97 if (!(q->flags & TCQ_F_ONETXQUEUE) ||
98 !netif_xmit_frozen_or_stopped(txq)) {
100 if (skb && qdisc_may_bulk(q))
101 try_bulk_dequeue_skb(q, skb, txq);
107 static inline int handle_dev_cpu_collision(struct sk_buff *skb,
108 struct netdev_queue *dev_queue,
113 if (unlikely(dev_queue->xmit_lock_owner == smp_processor_id())) {
115 * Same CPU holding the lock. It may be a transient
116 * configuration error, when hard_start_xmit() recurses. We
117 * detect it by checking xmit owner and drop the packet when
118 * deadloop is detected. Return OK to try the next skb.
121 net_warn_ratelimited("Dead loop on netdevice %s, fix it urgently!\n",
122 dev_queue->dev->name);
126 * Another cpu is holding lock, requeue & delay xmits for
129 __this_cpu_inc(softnet_data.cpu_collision);
130 ret = dev_requeue_skb(skb, q);
137 * Transmit possibly several skbs, and handle the return status as
138 * required. Holding the __QDISC___STATE_RUNNING bit guarantees that
139 * only one CPU can execute this function.
141 * Returns to the caller:
142 * 0 - queue is empty or throttled.
143 * >0 - queue is not empty.
145 int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
146 struct net_device *dev, struct netdev_queue *txq,
147 spinlock_t *root_lock, bool validate)
149 int ret = NETDEV_TX_BUSY;
151 /* And release qdisc */
152 spin_unlock(root_lock);
154 /* Note that we validate skb (GSO, checksum, ...) outside of locks */
156 skb = validate_xmit_skb_list(skb, dev);
159 HARD_TX_LOCK(dev, txq, smp_processor_id());
160 if (!netif_xmit_frozen_or_stopped(txq))
161 skb = dev_hard_start_xmit(skb, dev, txq, &ret);
163 HARD_TX_UNLOCK(dev, txq);
165 spin_lock(root_lock);
167 if (dev_xmit_complete(ret)) {
168 /* Driver sent out skb successfully or skb was consumed */
170 } else if (ret == NETDEV_TX_LOCKED) {
171 /* Driver try lock failed */
172 ret = handle_dev_cpu_collision(skb, txq, q);
174 /* Driver returned NETDEV_TX_BUSY - requeue skb */
175 if (unlikely(ret != NETDEV_TX_BUSY))
176 net_warn_ratelimited("BUG %s code %d qlen %d\n",
177 dev->name, ret, q->q.qlen);
179 ret = dev_requeue_skb(skb, q);
182 if (ret && netif_xmit_frozen_or_stopped(txq))
189 * NOTE: Called under qdisc_lock(q) with locally disabled BH.
191 * __QDISC___STATE_RUNNING guarantees only one CPU can process
192 * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
195 * netif_tx_lock serializes accesses to device driver.
197 * qdisc_lock(q) and netif_tx_lock are mutually exclusive,
198 * if one is grabbed, another must be free.
200 * Note, that this procedure can be called by a watchdog timer
202 * Returns to the caller:
203 * 0 - queue is empty or throttled.
204 * >0 - queue is not empty.
207 static inline int qdisc_restart(struct Qdisc *q)
209 struct netdev_queue *txq;
210 struct net_device *dev;
211 spinlock_t *root_lock;
216 skb = dequeue_skb(q, &validate);
220 root_lock = qdisc_lock(q);
222 txq = skb_get_tx_queue(dev, skb);
224 return sch_direct_xmit(skb, q, dev, txq, root_lock, validate);
227 void __qdisc_run(struct Qdisc *q)
229 int quota = weight_p;
231 while (qdisc_restart(q)) {
233 * Ordered by possible occurrence: Postpone processing if
234 * 1. we've exceeded packet quota
235 * 2. another process needs the CPU;
237 if (--quota <= 0 || need_resched()) {
246 unsigned long dev_trans_start(struct net_device *dev)
248 unsigned long val, res;
251 if (is_vlan_dev(dev))
252 dev = vlan_dev_real_dev(dev);
253 res = dev->trans_start;
254 for (i = 0; i < dev->num_tx_queues; i++) {
255 val = netdev_get_tx_queue(dev, i)->trans_start;
256 if (val && time_after(val, res))
259 dev->trans_start = res;
263 EXPORT_SYMBOL(dev_trans_start);
265 static void dev_watchdog(unsigned long arg)
267 struct net_device *dev = (struct net_device *)arg;
270 if (!qdisc_tx_is_noop(dev)) {
271 if (netif_device_present(dev) &&
272 netif_running(dev) &&
273 netif_carrier_ok(dev)) {
274 int some_queue_timedout = 0;
276 unsigned long trans_start;
278 for (i = 0; i < dev->num_tx_queues; i++) {
279 struct netdev_queue *txq;
281 txq = netdev_get_tx_queue(dev, i);
283 * old device drivers set dev->trans_start
285 trans_start = txq->trans_start ? : dev->trans_start;
286 if (netif_xmit_stopped(txq) &&
287 time_after(jiffies, (trans_start +
288 dev->watchdog_timeo))) {
289 some_queue_timedout = 1;
290 txq->trans_timeout++;
295 if (some_queue_timedout) {
296 WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",
297 dev->name, netdev_drivername(dev), i);
298 dev->netdev_ops->ndo_tx_timeout(dev);
300 if (!mod_timer(&dev->watchdog_timer,
301 round_jiffies(jiffies +
302 dev->watchdog_timeo)))
306 netif_tx_unlock(dev);
311 void __netdev_watchdog_up(struct net_device *dev)
313 if (dev->netdev_ops->ndo_tx_timeout) {
314 if (dev->watchdog_timeo <= 0)
315 dev->watchdog_timeo = 5*HZ;
316 if (!mod_timer(&dev->watchdog_timer,
317 round_jiffies(jiffies + dev->watchdog_timeo)))
322 static void dev_watchdog_up(struct net_device *dev)
324 __netdev_watchdog_up(dev);
327 static void dev_watchdog_down(struct net_device *dev)
329 netif_tx_lock_bh(dev);
330 if (del_timer(&dev->watchdog_timer))
332 netif_tx_unlock_bh(dev);
336 * netif_carrier_on - set carrier
337 * @dev: network device
339 * Device has detected that carrier.
341 void netif_carrier_on(struct net_device *dev)
343 if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
344 if (dev->reg_state == NETREG_UNINITIALIZED)
346 atomic_inc(&dev->carrier_changes);
347 linkwatch_fire_event(dev);
348 if (netif_running(dev))
349 __netdev_watchdog_up(dev);
352 EXPORT_SYMBOL(netif_carrier_on);
355 * netif_carrier_off - clear carrier
356 * @dev: network device
358 * Device has detected loss of carrier.
360 void netif_carrier_off(struct net_device *dev)
362 if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
363 if (dev->reg_state == NETREG_UNINITIALIZED)
365 atomic_inc(&dev->carrier_changes);
366 linkwatch_fire_event(dev);
369 EXPORT_SYMBOL(netif_carrier_off);
371 /* "NOOP" scheduler: the best scheduler, recommended for all interfaces
372 under all circumstances. It is difficult to invent anything faster or
376 static int noop_enqueue(struct sk_buff *skb, struct Qdisc *qdisc)
382 static struct sk_buff *noop_dequeue(struct Qdisc *qdisc)
387 struct Qdisc_ops noop_qdisc_ops __read_mostly = {
390 .enqueue = noop_enqueue,
391 .dequeue = noop_dequeue,
392 .peek = noop_dequeue,
393 .owner = THIS_MODULE,
396 static struct netdev_queue noop_netdev_queue = {
397 .qdisc = &noop_qdisc,
398 .qdisc_sleeping = &noop_qdisc,
401 struct Qdisc noop_qdisc = {
402 .enqueue = noop_enqueue,
403 .dequeue = noop_dequeue,
404 .flags = TCQ_F_BUILTIN,
405 .ops = &noop_qdisc_ops,
406 .list = LIST_HEAD_INIT(noop_qdisc.list),
407 .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
408 .dev_queue = &noop_netdev_queue,
409 .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
411 EXPORT_SYMBOL(noop_qdisc);
413 static struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
416 .enqueue = noop_enqueue,
417 .dequeue = noop_dequeue,
418 .peek = noop_dequeue,
419 .owner = THIS_MODULE,
422 static struct Qdisc noqueue_qdisc;
423 static struct netdev_queue noqueue_netdev_queue = {
424 .qdisc = &noqueue_qdisc,
425 .qdisc_sleeping = &noqueue_qdisc,
428 static struct Qdisc noqueue_qdisc = {
430 .dequeue = noop_dequeue,
431 .flags = TCQ_F_BUILTIN,
432 .ops = &noqueue_qdisc_ops,
433 .list = LIST_HEAD_INIT(noqueue_qdisc.list),
434 .q.lock = __SPIN_LOCK_UNLOCKED(noqueue_qdisc.q.lock),
435 .dev_queue = &noqueue_netdev_queue,
436 .busylock = __SPIN_LOCK_UNLOCKED(noqueue_qdisc.busylock),
440 static const u8 prio2band[TC_PRIO_MAX + 1] = {
441 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1
444 /* 3-band FIFO queue: old style, but should be a bit faster than
445 generic prio+fifo combination.
448 #define PFIFO_FAST_BANDS 3
451 * Private data for a pfifo_fast scheduler containing:
452 * - queues for the three band
453 * - bitmap indicating which of the bands contain skbs
455 struct pfifo_fast_priv {
457 struct sk_buff_head q[PFIFO_FAST_BANDS];
461 * Convert a bitmap to the first band number where an skb is queued, where:
462 * bitmap=0 means there are no skbs on any band.
463 * bitmap=1 means there is an skb on band 0.
464 * bitmap=7 means there are skbs on all 3 bands, etc.
466 static const int bitmap2band[] = {-1, 0, 1, 0, 2, 0, 1, 0};
468 static inline struct sk_buff_head *band2list(struct pfifo_fast_priv *priv,
471 return priv->q + band;
474 static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc)
476 if (skb_queue_len(&qdisc->q) < qdisc_dev(qdisc)->tx_queue_len) {
477 int band = prio2band[skb->priority & TC_PRIO_MAX];
478 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
479 struct sk_buff_head *list = band2list(priv, band);
481 priv->bitmap |= (1 << band);
483 return __qdisc_enqueue_tail(skb, qdisc, list);
486 return qdisc_drop(skb, qdisc);
489 static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
491 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
492 int band = bitmap2band[priv->bitmap];
494 if (likely(band >= 0)) {
495 struct sk_buff_head *list = band2list(priv, band);
496 struct sk_buff *skb = __qdisc_dequeue_head(qdisc, list);
499 if (skb_queue_empty(list))
500 priv->bitmap &= ~(1 << band);
508 static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
510 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
511 int band = bitmap2band[priv->bitmap];
514 struct sk_buff_head *list = band2list(priv, band);
516 return skb_peek(list);
522 static void pfifo_fast_reset(struct Qdisc *qdisc)
525 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
527 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
528 __qdisc_reset_queue(qdisc, band2list(priv, prio));
531 qdisc->qstats.backlog = 0;
535 static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
537 struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
539 memcpy(&opt.priomap, prio2band, TC_PRIO_MAX + 1);
540 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
541 goto nla_put_failure;
548 static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt)
551 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
553 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
554 __skb_queue_head_init(band2list(priv, prio));
556 /* Can by-pass the queue discipline */
557 qdisc->flags |= TCQ_F_CAN_BYPASS;
561 struct Qdisc_ops pfifo_fast_ops __read_mostly = {
563 .priv_size = sizeof(struct pfifo_fast_priv),
564 .enqueue = pfifo_fast_enqueue,
565 .dequeue = pfifo_fast_dequeue,
566 .peek = pfifo_fast_peek,
567 .init = pfifo_fast_init,
568 .reset = pfifo_fast_reset,
569 .dump = pfifo_fast_dump,
570 .owner = THIS_MODULE,
573 static struct lock_class_key qdisc_tx_busylock;
575 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
576 const struct Qdisc_ops *ops)
580 unsigned int size = QDISC_ALIGN(sizeof(*sch)) + ops->priv_size;
582 struct net_device *dev = dev_queue->dev;
584 p = kzalloc_node(size, GFP_KERNEL,
585 netdev_queue_numa_node_read(dev_queue));
589 sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
590 /* if we got non aligned memory, ask more and do alignment ourself */
593 p = kzalloc_node(size + QDISC_ALIGNTO - 1, GFP_KERNEL,
594 netdev_queue_numa_node_read(dev_queue));
597 sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
598 sch->padded = (char *) sch - (char *) p;
600 INIT_LIST_HEAD(&sch->list);
601 skb_queue_head_init(&sch->q);
603 spin_lock_init(&sch->busylock);
604 lockdep_set_class(&sch->busylock,
605 dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
608 sch->enqueue = ops->enqueue;
609 sch->dequeue = ops->dequeue;
610 sch->dev_queue = dev_queue;
612 atomic_set(&sch->refcnt, 1);
619 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
620 const struct Qdisc_ops *ops,
621 unsigned int parentid)
625 if (!try_module_get(ops->owner))
628 sch = qdisc_alloc(dev_queue, ops);
631 sch->parent = parentid;
633 if (!ops->init || ops->init(sch, NULL) == 0)
640 EXPORT_SYMBOL(qdisc_create_dflt);
642 /* Under qdisc_lock(qdisc) and BH! */
644 void qdisc_reset(struct Qdisc *qdisc)
646 const struct Qdisc_ops *ops = qdisc->ops;
651 if (qdisc->gso_skb) {
652 kfree_skb_list(qdisc->gso_skb);
653 qdisc->gso_skb = NULL;
657 EXPORT_SYMBOL(qdisc_reset);
659 static void qdisc_rcu_free(struct rcu_head *head)
661 struct Qdisc *qdisc = container_of(head, struct Qdisc, rcu_head);
663 if (qdisc_is_percpu_stats(qdisc))
664 free_percpu(qdisc->cpu_bstats);
666 kfree((char *) qdisc - qdisc->padded);
669 void qdisc_destroy(struct Qdisc *qdisc)
671 const struct Qdisc_ops *ops = qdisc->ops;
673 if (qdisc->flags & TCQ_F_BUILTIN ||
674 !atomic_dec_and_test(&qdisc->refcnt))
677 #ifdef CONFIG_NET_SCHED
678 qdisc_list_del(qdisc);
680 qdisc_put_stab(rtnl_dereference(qdisc->stab));
682 gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est);
688 module_put(ops->owner);
689 dev_put(qdisc_dev(qdisc));
691 kfree_skb_list(qdisc->gso_skb);
693 * gen_estimator est_timer() might access qdisc->q.lock,
694 * wait a RCU grace period before freeing qdisc.
696 call_rcu(&qdisc->rcu_head, qdisc_rcu_free);
698 EXPORT_SYMBOL(qdisc_destroy);
700 /* Attach toplevel qdisc to device queue. */
701 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
704 struct Qdisc *oqdisc = dev_queue->qdisc_sleeping;
705 spinlock_t *root_lock;
707 root_lock = qdisc_lock(oqdisc);
708 spin_lock_bh(root_lock);
710 /* Prune old scheduler */
711 if (oqdisc && atomic_read(&oqdisc->refcnt) <= 1)
714 /* ... and graft new one */
717 dev_queue->qdisc_sleeping = qdisc;
718 rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
720 spin_unlock_bh(root_lock);
724 EXPORT_SYMBOL(dev_graft_qdisc);
726 static void attach_one_default_qdisc(struct net_device *dev,
727 struct netdev_queue *dev_queue,
730 struct Qdisc *qdisc = &noqueue_qdisc;
732 if (dev->tx_queue_len) {
733 qdisc = qdisc_create_dflt(dev_queue,
734 default_qdisc_ops, TC_H_ROOT);
736 netdev_info(dev, "activation failed\n");
739 if (!netif_is_multiqueue(dev))
740 qdisc->flags |= TCQ_F_ONETXQUEUE;
742 dev_queue->qdisc_sleeping = qdisc;
745 static void attach_default_qdiscs(struct net_device *dev)
747 struct netdev_queue *txq;
750 txq = netdev_get_tx_queue(dev, 0);
752 if (!netif_is_multiqueue(dev) || dev->tx_queue_len == 0) {
753 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
754 dev->qdisc = txq->qdisc_sleeping;
755 atomic_inc(&dev->qdisc->refcnt);
757 qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT);
760 qdisc->ops->attach(qdisc);
765 static void transition_one_qdisc(struct net_device *dev,
766 struct netdev_queue *dev_queue,
767 void *_need_watchdog)
769 struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
770 int *need_watchdog_p = _need_watchdog;
772 if (!(new_qdisc->flags & TCQ_F_BUILTIN))
773 clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
775 rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
776 if (need_watchdog_p && new_qdisc != &noqueue_qdisc) {
777 dev_queue->trans_start = 0;
778 *need_watchdog_p = 1;
782 void dev_activate(struct net_device *dev)
786 /* No queueing discipline is attached to device;
787 * create default one for devices, which need queueing
788 * and noqueue_qdisc for virtual interfaces
791 if (dev->qdisc == &noop_qdisc)
792 attach_default_qdiscs(dev);
794 if (!netif_carrier_ok(dev))
795 /* Delay activation until next carrier-on event */
799 netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
800 if (dev_ingress_queue(dev))
801 transition_one_qdisc(dev, dev_ingress_queue(dev), NULL);
804 dev->trans_start = jiffies;
805 dev_watchdog_up(dev);
808 EXPORT_SYMBOL(dev_activate);
810 static void dev_deactivate_queue(struct net_device *dev,
811 struct netdev_queue *dev_queue,
812 void *_qdisc_default)
814 struct Qdisc *qdisc_default = _qdisc_default;
817 qdisc = rtnl_dereference(dev_queue->qdisc);
819 spin_lock_bh(qdisc_lock(qdisc));
821 if (!(qdisc->flags & TCQ_F_BUILTIN))
822 set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
824 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
827 spin_unlock_bh(qdisc_lock(qdisc));
831 static bool some_qdisc_is_busy(struct net_device *dev)
835 for (i = 0; i < dev->num_tx_queues; i++) {
836 struct netdev_queue *dev_queue;
837 spinlock_t *root_lock;
841 dev_queue = netdev_get_tx_queue(dev, i);
842 q = dev_queue->qdisc_sleeping;
843 root_lock = qdisc_lock(q);
845 spin_lock_bh(root_lock);
847 val = (qdisc_is_running(q) ||
848 test_bit(__QDISC_STATE_SCHED, &q->state));
850 spin_unlock_bh(root_lock);
859 * dev_deactivate_many - deactivate transmissions on several devices
860 * @head: list of devices to deactivate
862 * This function returns only when all outstanding transmissions
863 * have completed, unless all devices are in dismantle phase.
865 void dev_deactivate_many(struct list_head *head)
867 struct net_device *dev;
868 bool sync_needed = false;
870 list_for_each_entry(dev, head, close_list) {
871 netdev_for_each_tx_queue(dev, dev_deactivate_queue,
873 if (dev_ingress_queue(dev))
874 dev_deactivate_queue(dev, dev_ingress_queue(dev),
877 dev_watchdog_down(dev);
878 sync_needed |= !dev->dismantle;
881 /* Wait for outstanding qdisc-less dev_queue_xmit calls.
882 * This is avoided if all devices are in dismantle phase :
883 * Caller will call synchronize_net() for us
888 /* Wait for outstanding qdisc_run calls. */
889 list_for_each_entry(dev, head, close_list)
890 while (some_qdisc_is_busy(dev))
894 void dev_deactivate(struct net_device *dev)
898 list_add(&dev->close_list, &single);
899 dev_deactivate_many(&single);
902 EXPORT_SYMBOL(dev_deactivate);
904 static void dev_init_scheduler_queue(struct net_device *dev,
905 struct netdev_queue *dev_queue,
908 struct Qdisc *qdisc = _qdisc;
910 rcu_assign_pointer(dev_queue->qdisc, qdisc);
911 dev_queue->qdisc_sleeping = qdisc;
914 void dev_init_scheduler(struct net_device *dev)
916 dev->qdisc = &noop_qdisc;
917 netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
918 if (dev_ingress_queue(dev))
919 dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
921 setup_timer(&dev->watchdog_timer, dev_watchdog, (unsigned long)dev);
924 static void shutdown_scheduler_queue(struct net_device *dev,
925 struct netdev_queue *dev_queue,
926 void *_qdisc_default)
928 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
929 struct Qdisc *qdisc_default = _qdisc_default;
932 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
933 dev_queue->qdisc_sleeping = qdisc_default;
935 qdisc_destroy(qdisc);
939 void dev_shutdown(struct net_device *dev)
941 netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
942 if (dev_ingress_queue(dev))
943 shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
944 qdisc_destroy(dev->qdisc);
945 dev->qdisc = &noop_qdisc;
947 WARN_ON(timer_pending(&dev->watchdog_timer));
950 void psched_ratecfg_precompute(struct psched_ratecfg *r,
951 const struct tc_ratespec *conf,
954 memset(r, 0, sizeof(*r));
955 r->overhead = conf->overhead;
956 r->rate_bytes_ps = max_t(u64, conf->rate, rate64);
957 r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK);
960 * The deal here is to replace a divide by a reciprocal one
961 * in fast path (a reciprocal divide is a multiply and a shift)
963 * Normal formula would be :
964 * time_in_ns = (NSEC_PER_SEC * len) / rate_bps
966 * We compute mult/shift to use instead :
967 * time_in_ns = (len * mult) >> shift;
969 * We try to get the highest possible mult value for accuracy,
970 * but have to make sure no overflows will ever happen.
972 if (r->rate_bytes_ps > 0) {
973 u64 factor = NSEC_PER_SEC;
976 r->mult = div64_u64(factor, r->rate_bytes_ps);
977 if (r->mult & (1U << 31) || factor & (1ULL << 63))
984 EXPORT_SYMBOL(psched_ratecfg_precompute);