1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * net/sched/sch_generic.c Generic packet scheduler routines.
5 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6 * Jamal Hadi Salim, <hadi@cyberus.ca> 990601
10 #include <linux/bitops.h>
11 #include <linux/module.h>
12 #include <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/sched.h>
15 #include <linux/string.h>
16 #include <linux/errno.h>
17 #include <linux/netdevice.h>
18 #include <linux/skbuff.h>
19 #include <linux/rtnetlink.h>
20 #include <linux/init.h>
21 #include <linux/rcupdate.h>
22 #include <linux/list.h>
23 #include <linux/slab.h>
24 #include <linux/if_vlan.h>
25 #include <linux/skb_array.h>
26 #include <linux/if_macvlan.h>
27 #include <net/sch_generic.h>
28 #include <net/pkt_sched.h>
30 #include <trace/events/qdisc.h>
31 #include <trace/events/net.h>
34 /* Qdisc to use by default */
35 const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops;
36 EXPORT_SYMBOL(default_qdisc_ops);
38 /* Main transmission queue. */
40 /* Modifications to data participating in scheduling must be protected with
41 * qdisc_lock(qdisc) spinlock.
43 * The idea is the following:
44 * - enqueue, dequeue are serialized via qdisc root lock
45 * - ingress filtering is also serialized via qdisc root lock
46 * - updates to tree and tree walking are only done under the rtnl mutex.
49 static inline struct sk_buff *__skb_dequeue_bad_txq(struct Qdisc *q)
51 const struct netdev_queue *txq = q->dev_queue;
52 spinlock_t *lock = NULL;
55 if (q->flags & TCQ_F_NOLOCK) {
60 skb = skb_peek(&q->skb_bad_txq);
62 /* check the reason of requeuing without tx lock first */
63 txq = skb_get_tx_queue(txq->dev, skb);
64 if (!netif_xmit_frozen_or_stopped(txq)) {
65 skb = __skb_dequeue(&q->skb_bad_txq);
66 if (qdisc_is_percpu_stats(q)) {
67 qdisc_qstats_cpu_backlog_dec(q, skb);
68 qdisc_qstats_cpu_qlen_dec(q);
70 qdisc_qstats_backlog_dec(q, skb);
84 static inline struct sk_buff *qdisc_dequeue_skb_bad_txq(struct Qdisc *q)
86 struct sk_buff *skb = skb_peek(&q->skb_bad_txq);
89 skb = __skb_dequeue_bad_txq(q);
94 static inline void qdisc_enqueue_skb_bad_txq(struct Qdisc *q,
97 spinlock_t *lock = NULL;
99 if (q->flags & TCQ_F_NOLOCK) {
100 lock = qdisc_lock(q);
104 __skb_queue_tail(&q->skb_bad_txq, skb);
106 if (qdisc_is_percpu_stats(q)) {
107 qdisc_qstats_cpu_backlog_inc(q, skb);
108 qdisc_qstats_cpu_qlen_inc(q);
110 qdisc_qstats_backlog_inc(q, skb);
118 static inline void dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
120 spinlock_t *lock = NULL;
122 if (q->flags & TCQ_F_NOLOCK) {
123 lock = qdisc_lock(q);
128 struct sk_buff *next = skb->next;
130 __skb_queue_tail(&q->gso_skb, skb);
132 /* it's still part of the queue */
133 if (qdisc_is_percpu_stats(q)) {
134 qdisc_qstats_cpu_requeues_inc(q);
135 qdisc_qstats_cpu_backlog_inc(q, skb);
136 qdisc_qstats_cpu_qlen_inc(q);
138 q->qstats.requeues++;
139 qdisc_qstats_backlog_inc(q, skb);
150 static void try_bulk_dequeue_skb(struct Qdisc *q,
152 const struct netdev_queue *txq,
155 int bytelimit = qdisc_avail_bulklimit(txq) - skb->len;
157 while (bytelimit > 0) {
158 struct sk_buff *nskb = q->dequeue(q);
163 bytelimit -= nskb->len; /* covers GSO len */
166 (*packets)++; /* GSO counts as one pkt */
168 skb_mark_not_on_list(skb);
171 /* This variant of try_bulk_dequeue_skb() makes sure
172 * all skbs in the chain are for the same txq
174 static void try_bulk_dequeue_skb_slow(struct Qdisc *q,
178 int mapping = skb_get_queue_mapping(skb);
179 struct sk_buff *nskb;
183 nskb = q->dequeue(q);
186 if (unlikely(skb_get_queue_mapping(nskb) != mapping)) {
187 qdisc_enqueue_skb_bad_txq(q, nskb);
194 skb_mark_not_on_list(skb);
197 /* Note that dequeue_skb can possibly return a SKB list (via skb->next).
198 * A requeued skb (via q->gso_skb) can also be a SKB list.
200 static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
203 const struct netdev_queue *txq = q->dev_queue;
204 struct sk_buff *skb = NULL;
207 if (unlikely(!skb_queue_empty(&q->gso_skb))) {
208 spinlock_t *lock = NULL;
210 if (q->flags & TCQ_F_NOLOCK) {
211 lock = qdisc_lock(q);
215 skb = skb_peek(&q->gso_skb);
217 /* skb may be null if another cpu pulls gso_skb off in between
218 * empty check and lock.
226 /* skb in gso_skb were already validated */
228 if (xfrm_offload(skb))
230 /* check the reason of requeuing without tx lock first */
231 txq = skb_get_tx_queue(txq->dev, skb);
232 if (!netif_xmit_frozen_or_stopped(txq)) {
233 skb = __skb_dequeue(&q->gso_skb);
234 if (qdisc_is_percpu_stats(q)) {
235 qdisc_qstats_cpu_backlog_dec(q, skb);
236 qdisc_qstats_cpu_qlen_dec(q);
238 qdisc_qstats_backlog_dec(q, skb);
251 if ((q->flags & TCQ_F_ONETXQUEUE) &&
252 netif_xmit_frozen_or_stopped(txq))
255 skb = qdisc_dequeue_skb_bad_txq(q);
261 if (qdisc_may_bulk(q))
262 try_bulk_dequeue_skb(q, skb, txq, packets);
264 try_bulk_dequeue_skb_slow(q, skb, packets);
267 trace_qdisc_dequeue(q, txq, *packets, skb);
272 * Transmit possibly several skbs, and handle the return status as
273 * required. Owning running seqcount bit guarantees that
274 * only one CPU can execute this function.
276 * Returns to the caller:
277 * false - hardware queue frozen backoff
278 * true - feel free to send more pkts
280 bool sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
281 struct net_device *dev, struct netdev_queue *txq,
282 spinlock_t *root_lock, bool validate)
284 int ret = NETDEV_TX_BUSY;
287 /* And release qdisc */
289 spin_unlock(root_lock);
291 /* Note that we validate skb (GSO, checksum, ...) outside of locks */
293 skb = validate_xmit_skb_list(skb, dev, &again);
295 #ifdef CONFIG_XFRM_OFFLOAD
296 if (unlikely(again)) {
298 spin_lock(root_lock);
300 dev_requeue_skb(skb, q);
306 HARD_TX_LOCK(dev, txq, smp_processor_id());
307 if (!netif_xmit_frozen_or_stopped(txq))
308 skb = dev_hard_start_xmit(skb, dev, txq, &ret);
310 HARD_TX_UNLOCK(dev, txq);
313 spin_lock(root_lock);
318 spin_lock(root_lock);
320 if (!dev_xmit_complete(ret)) {
321 /* Driver returned NETDEV_TX_BUSY - requeue skb */
322 if (unlikely(ret != NETDEV_TX_BUSY))
323 net_warn_ratelimited("BUG %s code %d qlen %d\n",
324 dev->name, ret, q->q.qlen);
326 dev_requeue_skb(skb, q);
334 * NOTE: Called under qdisc_lock(q) with locally disabled BH.
336 * running seqcount guarantees only one CPU can process
337 * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
340 * netif_tx_lock serializes accesses to device driver.
342 * qdisc_lock(q) and netif_tx_lock are mutually exclusive,
343 * if one is grabbed, another must be free.
345 * Note, that this procedure can be called by a watchdog timer
347 * Returns to the caller:
348 * 0 - queue is empty or throttled.
349 * >0 - queue is not empty.
352 static inline bool qdisc_restart(struct Qdisc *q, int *packets)
354 spinlock_t *root_lock = NULL;
355 struct netdev_queue *txq;
356 struct net_device *dev;
361 skb = dequeue_skb(q, &validate, packets);
365 if (!(q->flags & TCQ_F_NOLOCK))
366 root_lock = qdisc_lock(q);
369 txq = skb_get_tx_queue(dev, skb);
371 return sch_direct_xmit(skb, q, dev, txq, root_lock, validate);
374 void __qdisc_run(struct Qdisc *q)
376 int quota = dev_tx_weight;
379 while (qdisc_restart(q, &packets)) {
381 * Ordered by possible occurrence: Postpone processing if
382 * 1. we've exceeded packet quota
383 * 2. another process needs the CPU;
386 if (quota <= 0 || need_resched()) {
393 unsigned long dev_trans_start(struct net_device *dev)
395 unsigned long val, res;
398 if (is_vlan_dev(dev))
399 dev = vlan_dev_real_dev(dev);
400 else if (netif_is_macvlan(dev))
401 dev = macvlan_dev_real_dev(dev);
402 res = netdev_get_tx_queue(dev, 0)->trans_start;
403 for (i = 1; i < dev->num_tx_queues; i++) {
404 val = netdev_get_tx_queue(dev, i)->trans_start;
405 if (val && time_after(val, res))
411 EXPORT_SYMBOL(dev_trans_start);
413 static void dev_watchdog(struct timer_list *t)
415 struct net_device *dev = from_timer(dev, t, watchdog_timer);
418 if (!qdisc_tx_is_noop(dev)) {
419 if (netif_device_present(dev) &&
420 netif_running(dev) &&
421 netif_carrier_ok(dev)) {
422 int some_queue_timedout = 0;
424 unsigned long trans_start;
426 for (i = 0; i < dev->num_tx_queues; i++) {
427 struct netdev_queue *txq;
429 txq = netdev_get_tx_queue(dev, i);
430 trans_start = txq->trans_start;
431 if (netif_xmit_stopped(txq) &&
432 time_after(jiffies, (trans_start +
433 dev->watchdog_timeo))) {
434 some_queue_timedout = 1;
435 txq->trans_timeout++;
440 if (some_queue_timedout) {
441 trace_net_dev_xmit_timeout(dev, i);
442 WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",
443 dev->name, netdev_drivername(dev), i);
444 dev->netdev_ops->ndo_tx_timeout(dev);
446 if (!mod_timer(&dev->watchdog_timer,
447 round_jiffies(jiffies +
448 dev->watchdog_timeo)))
452 netif_tx_unlock(dev);
457 void __netdev_watchdog_up(struct net_device *dev)
459 if (dev->netdev_ops->ndo_tx_timeout) {
460 if (dev->watchdog_timeo <= 0)
461 dev->watchdog_timeo = 5*HZ;
462 if (!mod_timer(&dev->watchdog_timer,
463 round_jiffies(jiffies + dev->watchdog_timeo)))
468 static void dev_watchdog_up(struct net_device *dev)
470 __netdev_watchdog_up(dev);
473 static void dev_watchdog_down(struct net_device *dev)
475 netif_tx_lock_bh(dev);
476 if (del_timer(&dev->watchdog_timer))
478 netif_tx_unlock_bh(dev);
482 * netif_carrier_on - set carrier
483 * @dev: network device
485 * Device has detected acquisition of carrier.
487 void netif_carrier_on(struct net_device *dev)
489 if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
490 if (dev->reg_state == NETREG_UNINITIALIZED)
492 atomic_inc(&dev->carrier_up_count);
493 linkwatch_fire_event(dev);
494 if (netif_running(dev))
495 __netdev_watchdog_up(dev);
498 EXPORT_SYMBOL(netif_carrier_on);
501 * netif_carrier_off - clear carrier
502 * @dev: network device
504 * Device has detected loss of carrier.
506 void netif_carrier_off(struct net_device *dev)
508 if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
509 if (dev->reg_state == NETREG_UNINITIALIZED)
511 atomic_inc(&dev->carrier_down_count);
512 linkwatch_fire_event(dev);
515 EXPORT_SYMBOL(netif_carrier_off);
517 /* "NOOP" scheduler: the best scheduler, recommended for all interfaces
518 under all circumstances. It is difficult to invent anything faster or
522 static int noop_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
523 struct sk_buff **to_free)
525 __qdisc_drop(skb, to_free);
529 static struct sk_buff *noop_dequeue(struct Qdisc *qdisc)
534 struct Qdisc_ops noop_qdisc_ops __read_mostly = {
537 .enqueue = noop_enqueue,
538 .dequeue = noop_dequeue,
539 .peek = noop_dequeue,
540 .owner = THIS_MODULE,
543 static struct netdev_queue noop_netdev_queue = {
544 RCU_POINTER_INITIALIZER(qdisc, &noop_qdisc),
545 .qdisc_sleeping = &noop_qdisc,
548 struct Qdisc noop_qdisc = {
549 .enqueue = noop_enqueue,
550 .dequeue = noop_dequeue,
551 .flags = TCQ_F_BUILTIN,
552 .ops = &noop_qdisc_ops,
553 .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
554 .dev_queue = &noop_netdev_queue,
555 .running = SEQCNT_ZERO(noop_qdisc.running),
556 .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
558 .next = (struct sk_buff *)&noop_qdisc.gso_skb,
559 .prev = (struct sk_buff *)&noop_qdisc.gso_skb,
561 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.gso_skb.lock),
564 .next = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
565 .prev = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
567 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.skb_bad_txq.lock),
570 EXPORT_SYMBOL(noop_qdisc);
572 static int noqueue_init(struct Qdisc *qdisc, struct nlattr *opt,
573 struct netlink_ext_ack *extack)
575 /* register_qdisc() assigns a default of noop_enqueue if unset,
576 * but __dev_queue_xmit() treats noqueue only as such
577 * if this is NULL - so clear it here. */
578 qdisc->enqueue = NULL;
582 struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
585 .init = noqueue_init,
586 .enqueue = noop_enqueue,
587 .dequeue = noop_dequeue,
588 .peek = noop_dequeue,
589 .owner = THIS_MODULE,
592 static const u8 prio2band[TC_PRIO_MAX + 1] = {
593 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1
596 /* 3-band FIFO queue: old style, but should be a bit faster than
597 generic prio+fifo combination.
600 #define PFIFO_FAST_BANDS 3
603 * Private data for a pfifo_fast scheduler containing:
604 * - rings for priority bands
606 struct pfifo_fast_priv {
607 struct skb_array q[PFIFO_FAST_BANDS];
610 static inline struct skb_array *band2list(struct pfifo_fast_priv *priv,
613 return &priv->q[band];
616 static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
617 struct sk_buff **to_free)
619 int band = prio2band[skb->priority & TC_PRIO_MAX];
620 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
621 struct skb_array *q = band2list(priv, band);
622 unsigned int pkt_len = qdisc_pkt_len(skb);
625 err = skb_array_produce(q, skb);
628 if (qdisc_is_percpu_stats(qdisc))
629 return qdisc_drop_cpu(skb, qdisc, to_free);
631 return qdisc_drop(skb, qdisc, to_free);
634 qdisc_update_stats_at_enqueue(qdisc, pkt_len);
635 return NET_XMIT_SUCCESS;
638 static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
640 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
641 struct sk_buff *skb = NULL;
644 for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
645 struct skb_array *q = band2list(priv, band);
647 if (__skb_array_empty(q))
650 skb = __skb_array_consume(q);
653 qdisc_update_stats_at_dequeue(qdisc, skb);
661 static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
663 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
664 struct sk_buff *skb = NULL;
667 for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
668 struct skb_array *q = band2list(priv, band);
670 skb = __skb_array_peek(q);
676 static void pfifo_fast_reset(struct Qdisc *qdisc)
679 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
681 for (band = 0; band < PFIFO_FAST_BANDS; band++) {
682 struct skb_array *q = band2list(priv, band);
685 /* NULL ring is possible if destroy path is due to a failed
686 * skb_array_init() in pfifo_fast_init() case.
691 while ((skb = __skb_array_consume(q)) != NULL)
695 if (qdisc_is_percpu_stats(qdisc)) {
696 for_each_possible_cpu(i) {
697 struct gnet_stats_queue *q;
699 q = per_cpu_ptr(qdisc->cpu_qstats, i);
706 static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
708 struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
710 memcpy(&opt.priomap, prio2band, TC_PRIO_MAX + 1);
711 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
712 goto nla_put_failure;
719 static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt,
720 struct netlink_ext_ack *extack)
722 unsigned int qlen = qdisc_dev(qdisc)->tx_queue_len;
723 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
726 /* guard against zero length rings */
730 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
731 struct skb_array *q = band2list(priv, prio);
734 err = skb_array_init(q, qlen, GFP_KERNEL);
739 /* Can by-pass the queue discipline */
740 qdisc->flags |= TCQ_F_CAN_BYPASS;
744 static void pfifo_fast_destroy(struct Qdisc *sch)
746 struct pfifo_fast_priv *priv = qdisc_priv(sch);
749 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
750 struct skb_array *q = band2list(priv, prio);
752 /* NULL ring is possible if destroy path is due to a failed
753 * skb_array_init() in pfifo_fast_init() case.
757 /* Destroy ring but no need to kfree_skb because a call to
758 * pfifo_fast_reset() has already done that work.
760 ptr_ring_cleanup(&q->ring, NULL);
764 static int pfifo_fast_change_tx_queue_len(struct Qdisc *sch,
765 unsigned int new_len)
767 struct pfifo_fast_priv *priv = qdisc_priv(sch);
768 struct skb_array *bands[PFIFO_FAST_BANDS];
771 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
772 struct skb_array *q = band2list(priv, prio);
777 return skb_array_resize_multiple(bands, PFIFO_FAST_BANDS, new_len,
781 struct Qdisc_ops pfifo_fast_ops __read_mostly = {
783 .priv_size = sizeof(struct pfifo_fast_priv),
784 .enqueue = pfifo_fast_enqueue,
785 .dequeue = pfifo_fast_dequeue,
786 .peek = pfifo_fast_peek,
787 .init = pfifo_fast_init,
788 .destroy = pfifo_fast_destroy,
789 .reset = pfifo_fast_reset,
790 .dump = pfifo_fast_dump,
791 .change_tx_queue_len = pfifo_fast_change_tx_queue_len,
792 .owner = THIS_MODULE,
793 .static_flags = TCQ_F_NOLOCK | TCQ_F_CPUSTATS,
795 EXPORT_SYMBOL(pfifo_fast_ops);
797 static struct lock_class_key qdisc_tx_busylock;
798 static struct lock_class_key qdisc_running_key;
800 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
801 const struct Qdisc_ops *ops,
802 struct netlink_ext_ack *extack)
806 unsigned int size = QDISC_ALIGN(sizeof(*sch)) + ops->priv_size;
808 struct net_device *dev;
811 NL_SET_ERR_MSG(extack, "No device queue given");
816 dev = dev_queue->dev;
817 p = kzalloc_node(size, GFP_KERNEL,
818 netdev_queue_numa_node_read(dev_queue));
822 sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
823 /* if we got non aligned memory, ask more and do alignment ourself */
826 p = kzalloc_node(size + QDISC_ALIGNTO - 1, GFP_KERNEL,
827 netdev_queue_numa_node_read(dev_queue));
830 sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
831 sch->padded = (char *) sch - (char *) p;
833 __skb_queue_head_init(&sch->gso_skb);
834 __skb_queue_head_init(&sch->skb_bad_txq);
835 qdisc_skb_head_init(&sch->q);
836 spin_lock_init(&sch->q.lock);
838 if (ops->static_flags & TCQ_F_CPUSTATS) {
840 netdev_alloc_pcpu_stats(struct gnet_stats_basic_cpu);
841 if (!sch->cpu_bstats)
844 sch->cpu_qstats = alloc_percpu(struct gnet_stats_queue);
845 if (!sch->cpu_qstats) {
846 free_percpu(sch->cpu_bstats);
851 spin_lock_init(&sch->busylock);
852 lockdep_set_class(&sch->busylock,
853 dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
855 /* seqlock has the same scope of busylock, for NOLOCK qdisc */
856 spin_lock_init(&sch->seqlock);
857 lockdep_set_class(&sch->busylock,
858 dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
860 seqcount_init(&sch->running);
861 lockdep_set_class(&sch->running,
862 dev->qdisc_running_key ?: &qdisc_running_key);
865 sch->flags = ops->static_flags;
866 sch->enqueue = ops->enqueue;
867 sch->dequeue = ops->dequeue;
868 sch->dev_queue = dev_queue;
871 refcount_set(&sch->refcnt, 1);
880 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
881 const struct Qdisc_ops *ops,
882 unsigned int parentid,
883 struct netlink_ext_ack *extack)
887 if (!try_module_get(ops->owner)) {
888 NL_SET_ERR_MSG(extack, "Failed to increase module reference counter");
892 sch = qdisc_alloc(dev_queue, ops, extack);
894 module_put(ops->owner);
897 sch->parent = parentid;
899 if (!ops->init || ops->init(sch, NULL, extack) == 0)
905 EXPORT_SYMBOL(qdisc_create_dflt);
907 /* Under qdisc_lock(qdisc) and BH! */
909 void qdisc_reset(struct Qdisc *qdisc)
911 const struct Qdisc_ops *ops = qdisc->ops;
912 struct sk_buff *skb, *tmp;
917 skb_queue_walk_safe(&qdisc->gso_skb, skb, tmp) {
918 __skb_unlink(skb, &qdisc->gso_skb);
922 skb_queue_walk_safe(&qdisc->skb_bad_txq, skb, tmp) {
923 __skb_unlink(skb, &qdisc->skb_bad_txq);
928 qdisc->qstats.backlog = 0;
930 EXPORT_SYMBOL(qdisc_reset);
932 void qdisc_free(struct Qdisc *qdisc)
934 if (qdisc_is_percpu_stats(qdisc)) {
935 free_percpu(qdisc->cpu_bstats);
936 free_percpu(qdisc->cpu_qstats);
939 kfree((char *) qdisc - qdisc->padded);
942 static void qdisc_free_cb(struct rcu_head *head)
944 struct Qdisc *q = container_of(head, struct Qdisc, rcu);
949 static void qdisc_destroy(struct Qdisc *qdisc)
951 const struct Qdisc_ops *ops = qdisc->ops;
952 struct sk_buff *skb, *tmp;
954 #ifdef CONFIG_NET_SCHED
955 qdisc_hash_del(qdisc);
957 qdisc_put_stab(rtnl_dereference(qdisc->stab));
959 gen_kill_estimator(&qdisc->rate_est);
965 module_put(ops->owner);
966 dev_put(qdisc_dev(qdisc));
968 skb_queue_walk_safe(&qdisc->gso_skb, skb, tmp) {
969 __skb_unlink(skb, &qdisc->gso_skb);
973 skb_queue_walk_safe(&qdisc->skb_bad_txq, skb, tmp) {
974 __skb_unlink(skb, &qdisc->skb_bad_txq);
978 call_rcu(&qdisc->rcu, qdisc_free_cb);
981 void qdisc_put(struct Qdisc *qdisc)
983 if (qdisc->flags & TCQ_F_BUILTIN ||
984 !refcount_dec_and_test(&qdisc->refcnt))
987 qdisc_destroy(qdisc);
989 EXPORT_SYMBOL(qdisc_put);
991 /* Version of qdisc_put() that is called with rtnl mutex unlocked.
992 * Intended to be used as optimization, this function only takes rtnl lock if
993 * qdisc reference counter reached zero.
996 void qdisc_put_unlocked(struct Qdisc *qdisc)
998 if (qdisc->flags & TCQ_F_BUILTIN ||
999 !refcount_dec_and_rtnl_lock(&qdisc->refcnt))
1002 qdisc_destroy(qdisc);
1005 EXPORT_SYMBOL(qdisc_put_unlocked);
1007 /* Attach toplevel qdisc to device queue. */
1008 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
1009 struct Qdisc *qdisc)
1011 struct Qdisc *oqdisc = dev_queue->qdisc_sleeping;
1012 spinlock_t *root_lock;
1014 root_lock = qdisc_lock(oqdisc);
1015 spin_lock_bh(root_lock);
1017 /* ... and graft new one */
1019 qdisc = &noop_qdisc;
1020 dev_queue->qdisc_sleeping = qdisc;
1021 rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
1023 spin_unlock_bh(root_lock);
1027 EXPORT_SYMBOL(dev_graft_qdisc);
1029 static void attach_one_default_qdisc(struct net_device *dev,
1030 struct netdev_queue *dev_queue,
1033 struct Qdisc *qdisc;
1034 const struct Qdisc_ops *ops = default_qdisc_ops;
1036 if (dev->priv_flags & IFF_NO_QUEUE)
1037 ops = &noqueue_qdisc_ops;
1039 qdisc = qdisc_create_dflt(dev_queue, ops, TC_H_ROOT, NULL);
1041 netdev_info(dev, "activation failed\n");
1044 if (!netif_is_multiqueue(dev))
1045 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
1046 dev_queue->qdisc_sleeping = qdisc;
1049 static void attach_default_qdiscs(struct net_device *dev)
1051 struct netdev_queue *txq;
1052 struct Qdisc *qdisc;
1054 txq = netdev_get_tx_queue(dev, 0);
1056 if (!netif_is_multiqueue(dev) ||
1057 dev->priv_flags & IFF_NO_QUEUE) {
1058 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
1059 dev->qdisc = txq->qdisc_sleeping;
1060 qdisc_refcount_inc(dev->qdisc);
1062 qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT, NULL);
1065 qdisc->ops->attach(qdisc);
1068 #ifdef CONFIG_NET_SCHED
1069 if (dev->qdisc != &noop_qdisc)
1070 qdisc_hash_add(dev->qdisc, false);
1074 static void transition_one_qdisc(struct net_device *dev,
1075 struct netdev_queue *dev_queue,
1076 void *_need_watchdog)
1078 struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
1079 int *need_watchdog_p = _need_watchdog;
1081 if (!(new_qdisc->flags & TCQ_F_BUILTIN))
1082 clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
1084 rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
1085 if (need_watchdog_p) {
1086 dev_queue->trans_start = 0;
1087 *need_watchdog_p = 1;
1091 void dev_activate(struct net_device *dev)
1095 /* No queueing discipline is attached to device;
1096 * create default one for devices, which need queueing
1097 * and noqueue_qdisc for virtual interfaces
1100 if (dev->qdisc == &noop_qdisc)
1101 attach_default_qdiscs(dev);
1103 if (!netif_carrier_ok(dev))
1104 /* Delay activation until next carrier-on event */
1108 netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
1109 if (dev_ingress_queue(dev))
1110 transition_one_qdisc(dev, dev_ingress_queue(dev), NULL);
1112 if (need_watchdog) {
1113 netif_trans_update(dev);
1114 dev_watchdog_up(dev);
1117 EXPORT_SYMBOL(dev_activate);
1119 static void dev_deactivate_queue(struct net_device *dev,
1120 struct netdev_queue *dev_queue,
1121 void *_qdisc_default)
1123 struct Qdisc *qdisc_default = _qdisc_default;
1124 struct Qdisc *qdisc;
1126 qdisc = rtnl_dereference(dev_queue->qdisc);
1128 bool nolock = qdisc->flags & TCQ_F_NOLOCK;
1131 spin_lock_bh(&qdisc->seqlock);
1132 spin_lock_bh(qdisc_lock(qdisc));
1134 if (!(qdisc->flags & TCQ_F_BUILTIN))
1135 set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
1137 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1140 spin_unlock_bh(qdisc_lock(qdisc));
1142 spin_unlock_bh(&qdisc->seqlock);
1146 static bool some_qdisc_is_busy(struct net_device *dev)
1150 for (i = 0; i < dev->num_tx_queues; i++) {
1151 struct netdev_queue *dev_queue;
1152 spinlock_t *root_lock;
1156 dev_queue = netdev_get_tx_queue(dev, i);
1157 q = dev_queue->qdisc_sleeping;
1159 root_lock = qdisc_lock(q);
1160 spin_lock_bh(root_lock);
1162 val = (qdisc_is_running(q) ||
1163 test_bit(__QDISC_STATE_SCHED, &q->state));
1165 spin_unlock_bh(root_lock);
1173 static void dev_qdisc_reset(struct net_device *dev,
1174 struct netdev_queue *dev_queue,
1177 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1184 * dev_deactivate_many - deactivate transmissions on several devices
1185 * @head: list of devices to deactivate
1187 * This function returns only when all outstanding transmissions
1188 * have completed, unless all devices are in dismantle phase.
1190 void dev_deactivate_many(struct list_head *head)
1192 struct net_device *dev;
1194 list_for_each_entry(dev, head, close_list) {
1195 netdev_for_each_tx_queue(dev, dev_deactivate_queue,
1197 if (dev_ingress_queue(dev))
1198 dev_deactivate_queue(dev, dev_ingress_queue(dev),
1201 dev_watchdog_down(dev);
1204 /* Wait for outstanding qdisc-less dev_queue_xmit calls.
1205 * This is avoided if all devices are in dismantle phase :
1206 * Caller will call synchronize_net() for us
1210 /* Wait for outstanding qdisc_run calls. */
1211 list_for_each_entry(dev, head, close_list) {
1212 while (some_qdisc_is_busy(dev))
1214 /* The new qdisc is assigned at this point so we can safely
1215 * unwind stale skb lists and qdisc statistics
1217 netdev_for_each_tx_queue(dev, dev_qdisc_reset, NULL);
1218 if (dev_ingress_queue(dev))
1219 dev_qdisc_reset(dev, dev_ingress_queue(dev), NULL);
1223 void dev_deactivate(struct net_device *dev)
1227 list_add(&dev->close_list, &single);
1228 dev_deactivate_many(&single);
1231 EXPORT_SYMBOL(dev_deactivate);
1233 static int qdisc_change_tx_queue_len(struct net_device *dev,
1234 struct netdev_queue *dev_queue)
1236 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1237 const struct Qdisc_ops *ops = qdisc->ops;
1239 if (ops->change_tx_queue_len)
1240 return ops->change_tx_queue_len(qdisc, dev->tx_queue_len);
1244 int dev_qdisc_change_tx_queue_len(struct net_device *dev)
1246 bool up = dev->flags & IFF_UP;
1251 dev_deactivate(dev);
1253 for (i = 0; i < dev->num_tx_queues; i++) {
1254 ret = qdisc_change_tx_queue_len(dev, &dev->_tx[i]);
1256 /* TODO: revert changes on a partial failure */
1266 static void dev_init_scheduler_queue(struct net_device *dev,
1267 struct netdev_queue *dev_queue,
1270 struct Qdisc *qdisc = _qdisc;
1272 rcu_assign_pointer(dev_queue->qdisc, qdisc);
1273 dev_queue->qdisc_sleeping = qdisc;
1276 void dev_init_scheduler(struct net_device *dev)
1278 dev->qdisc = &noop_qdisc;
1279 netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
1280 if (dev_ingress_queue(dev))
1281 dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1283 timer_setup(&dev->watchdog_timer, dev_watchdog, 0);
1286 static void shutdown_scheduler_queue(struct net_device *dev,
1287 struct netdev_queue *dev_queue,
1288 void *_qdisc_default)
1290 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1291 struct Qdisc *qdisc_default = _qdisc_default;
1294 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1295 dev_queue->qdisc_sleeping = qdisc_default;
1301 void dev_shutdown(struct net_device *dev)
1303 netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
1304 if (dev_ingress_queue(dev))
1305 shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1306 qdisc_put(dev->qdisc);
1307 dev->qdisc = &noop_qdisc;
1309 WARN_ON(timer_pending(&dev->watchdog_timer));
1312 void psched_ratecfg_precompute(struct psched_ratecfg *r,
1313 const struct tc_ratespec *conf,
1316 memset(r, 0, sizeof(*r));
1317 r->overhead = conf->overhead;
1318 r->rate_bytes_ps = max_t(u64, conf->rate, rate64);
1319 r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK);
1322 * The deal here is to replace a divide by a reciprocal one
1323 * in fast path (a reciprocal divide is a multiply and a shift)
1325 * Normal formula would be :
1326 * time_in_ns = (NSEC_PER_SEC * len) / rate_bps
1328 * We compute mult/shift to use instead :
1329 * time_in_ns = (len * mult) >> shift;
1331 * We try to get the highest possible mult value for accuracy,
1332 * but have to make sure no overflows will ever happen.
1334 if (r->rate_bytes_ps > 0) {
1335 u64 factor = NSEC_PER_SEC;
1338 r->mult = div64_u64(factor, r->rate_bytes_ps);
1339 if (r->mult & (1U << 31) || factor & (1ULL << 63))
1346 EXPORT_SYMBOL(psched_ratecfg_precompute);
1348 static void mini_qdisc_rcu_func(struct rcu_head *head)
1352 void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp,
1353 struct tcf_proto *tp_head)
1355 /* Protected with chain0->filter_chain_lock.
1356 * Can't access chain directly because tp_head can be NULL.
1358 struct mini_Qdisc *miniq_old =
1359 rcu_dereference_protected(*miniqp->p_miniq, 1);
1360 struct mini_Qdisc *miniq;
1363 RCU_INIT_POINTER(*miniqp->p_miniq, NULL);
1364 /* Wait for flying RCU callback before it is freed. */
1369 miniq = !miniq_old || miniq_old == &miniqp->miniq2 ?
1370 &miniqp->miniq1 : &miniqp->miniq2;
1372 /* We need to make sure that readers won't see the miniq
1373 * we are about to modify. So wait until previous call_rcu callback
1377 miniq->filter_list = tp_head;
1378 rcu_assign_pointer(*miniqp->p_miniq, miniq);
1381 /* This is counterpart of the rcu barriers above. We need to
1382 * block potential new user of miniq_old until all readers
1383 * are not seeing it.
1385 call_rcu(&miniq_old->rcu, mini_qdisc_rcu_func);
1387 EXPORT_SYMBOL(mini_qdisc_pair_swap);
1389 void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc,
1390 struct mini_Qdisc __rcu **p_miniq)
1392 miniqp->miniq1.cpu_bstats = qdisc->cpu_bstats;
1393 miniqp->miniq1.cpu_qstats = qdisc->cpu_qstats;
1394 miniqp->miniq2.cpu_bstats = qdisc->cpu_bstats;
1395 miniqp->miniq2.cpu_qstats = qdisc->cpu_qstats;
1396 miniqp->p_miniq = p_miniq;
1398 EXPORT_SYMBOL(mini_qdisc_pair_init);