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1/*
2 * net/sched/sch_generic.c Generic packet scheduler routines.
3 *
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.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 * Jamal Hadi Salim, <hadi@cyberus.ca> 990601
11 * - Ingress support
12 */
13
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>
31#include <net/dst.h>
32
33/* Qdisc to use by default */
34const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops;
35EXPORT_SYMBOL(default_qdisc_ops);
36
37/* Main transmission queue. */
38
39/* Modifications to data participating in scheduling must be protected with
40 * qdisc_lock(qdisc) spinlock.
41 *
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.
46 */
47
48static inline int dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
49{
50 q->gso_skb = skb;
51 q->qstats.requeues++;
52 q->q.qlen++; /* it's still part of the queue */
53 __netif_schedule(q);
54
55 return 0;
56}
57
58static void try_bulk_dequeue_skb(struct Qdisc *q,
59 struct sk_buff *skb,
60 const struct netdev_queue *txq,
61 int *packets)
62{
63 int bytelimit = qdisc_avail_bulklimit(txq) - skb->len;
64
65 while (bytelimit > 0) {
66 struct sk_buff *nskb = q->dequeue(q);
67
68 if (!nskb)
69 break;
70
71 bytelimit -= nskb->len; /* covers GSO len */
72 skb->next = nskb;
73 skb = nskb;
74 (*packets)++; /* GSO counts as one pkt */
75 }
76 skb->next = NULL;
77}
78
79/* Note that dequeue_skb can possibly return a SKB list (via skb->next).
80 * A requeued skb (via q->gso_skb) can also be a SKB list.
81 */
82static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
83 int *packets)
84{
85 struct sk_buff *skb = q->gso_skb;
86 const struct netdev_queue *txq = q->dev_queue;
87
88 *packets = 1;
89 *validate = true;
90 if (unlikely(skb)) {
91 /* check the reason of requeuing without tx lock first */
92 txq = skb_get_tx_queue(txq->dev, skb);
93 if (!netif_xmit_frozen_or_stopped(txq)) {
94 q->gso_skb = NULL;
95 q->q.qlen--;
96 } else
97 skb = NULL;
98 /* skb in gso_skb were already validated */
99 *validate = false;
100 } else {
101 if (!(q->flags & TCQ_F_ONETXQUEUE) ||
102 !netif_xmit_frozen_or_stopped(txq)) {
103 skb = q->dequeue(q);
104 if (skb && qdisc_may_bulk(q))
105 try_bulk_dequeue_skb(q, skb, txq, packets);
106 }
107 }
108 return skb;
109}
110
111static inline int handle_dev_cpu_collision(struct sk_buff *skb,
112 struct netdev_queue *dev_queue,
113 struct Qdisc *q)
114{
115 int ret;
116
117 if (unlikely(dev_queue->xmit_lock_owner == smp_processor_id())) {
118 /*
119 * Same CPU holding the lock. It may be a transient
120 * configuration error, when hard_start_xmit() recurses. We
121 * detect it by checking xmit owner and drop the packet when
122 * deadloop is detected. Return OK to try the next skb.
123 */
124 kfree_skb_list(skb);
125 net_warn_ratelimited("Dead loop on netdevice %s, fix it urgently!\n",
126 dev_queue->dev->name);
127 ret = qdisc_qlen(q);
128 } else {
129 /*
130 * Another cpu is holding lock, requeue & delay xmits for
131 * some time.
132 */
133 __this_cpu_inc(softnet_data.cpu_collision);
134 ret = dev_requeue_skb(skb, q);
135 }
136
137 return ret;
138}
139
140/*
141 * Transmit possibly several skbs, and handle the return status as
142 * required. Holding the __QDISC___STATE_RUNNING bit guarantees that
143 * only one CPU can execute this function.
144 *
145 * Returns to the caller:
146 * 0 - queue is empty or throttled.
147 * >0 - queue is not empty.
148 */
149int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
150 struct net_device *dev, struct netdev_queue *txq,
151 spinlock_t *root_lock, bool validate)
152{
153 int ret = NETDEV_TX_BUSY;
154
155 /* And release qdisc */
156 spin_unlock(root_lock);
157
158 /* Note that we validate skb (GSO, checksum, ...) outside of locks */
159 if (validate)
160 skb = validate_xmit_skb_list(skb, dev);
161
162 if (likely(skb)) {
163 HARD_TX_LOCK(dev, txq, smp_processor_id());
164 if (!netif_xmit_frozen_or_stopped(txq))
165 skb = dev_hard_start_xmit(skb, dev, txq, &ret);
166
167 HARD_TX_UNLOCK(dev, txq);
168 } else {
169 spin_lock(root_lock);
170 return qdisc_qlen(q);
171 }
172 spin_lock(root_lock);
173
174 if (dev_xmit_complete(ret)) {
175 /* Driver sent out skb successfully or skb was consumed */
176 ret = qdisc_qlen(q);
177 } else if (ret == NETDEV_TX_LOCKED) {
178 /* Driver try lock failed */
179 ret = handle_dev_cpu_collision(skb, txq, q);
180 } else {
181 /* Driver returned NETDEV_TX_BUSY - requeue skb */
182 if (unlikely(ret != NETDEV_TX_BUSY))
183 net_warn_ratelimited("BUG %s code %d qlen %d\n",
184 dev->name, ret, q->q.qlen);
185
186 ret = dev_requeue_skb(skb, q);
187 }
188
189 if (ret && netif_xmit_frozen_or_stopped(txq))
190 ret = 0;
191
192 return ret;
193}
194
195/*
196 * NOTE: Called under qdisc_lock(q) with locally disabled BH.
197 *
198 * __QDISC___STATE_RUNNING guarantees only one CPU can process
199 * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
200 * this queue.
201 *
202 * netif_tx_lock serializes accesses to device driver.
203 *
204 * qdisc_lock(q) and netif_tx_lock are mutually exclusive,
205 * if one is grabbed, another must be free.
206 *
207 * Note, that this procedure can be called by a watchdog timer
208 *
209 * Returns to the caller:
210 * 0 - queue is empty or throttled.
211 * >0 - queue is not empty.
212 *
213 */
214static inline int qdisc_restart(struct Qdisc *q, int *packets)
215{
216 struct netdev_queue *txq;
217 struct net_device *dev;
218 spinlock_t *root_lock;
219 struct sk_buff *skb;
220 bool validate;
221
222 /* Dequeue packet */
223 skb = dequeue_skb(q, &validate, packets);
224 if (unlikely(!skb))
225 return 0;
226
227 root_lock = qdisc_lock(q);
228 dev = qdisc_dev(q);
229 txq = skb_get_tx_queue(dev, skb);
230
231 return sch_direct_xmit(skb, q, dev, txq, root_lock, validate);
232}
233
234void __qdisc_run(struct Qdisc *q)
235{
236 int quota = weight_p;
237 int packets;
238
239 while (qdisc_restart(q, &packets)) {
240 /*
241 * Ordered by possible occurrence: Postpone processing if
242 * 1. we've exceeded packet quota
243 * 2. another process needs the CPU;
244 */
245 quota -= packets;
246 if (quota <= 0 || need_resched()) {
247 __netif_schedule(q);
248 break;
249 }
250 }
251
252 qdisc_run_end(q);
253}
254
255unsigned long dev_trans_start(struct net_device *dev)
256{
257 unsigned long val, res;
258 unsigned int i;
259
260 if (is_vlan_dev(dev))
261 dev = vlan_dev_real_dev(dev);
262 res = dev->trans_start;
263 for (i = 0; i < dev->num_tx_queues; i++) {
264 val = netdev_get_tx_queue(dev, i)->trans_start;
265 if (val && time_after(val, res))
266 res = val;
267 }
268 dev->trans_start = res;
269
270 return res;
271}
272EXPORT_SYMBOL(dev_trans_start);
273
274static void dev_watchdog(unsigned long arg)
275{
276 struct net_device *dev = (struct net_device *)arg;
277
278 netif_tx_lock(dev);
279 if (!qdisc_tx_is_noop(dev)) {
280 if (netif_device_present(dev) &&
281 netif_running(dev) &&
282 netif_carrier_ok(dev)) {
283 int some_queue_timedout = 0;
284 unsigned int i;
285 unsigned long trans_start;
286
287 for (i = 0; i < dev->num_tx_queues; i++) {
288 struct netdev_queue *txq;
289
290 txq = netdev_get_tx_queue(dev, i);
291 /*
292 * old device drivers set dev->trans_start
293 */
294 trans_start = txq->trans_start ? : dev->trans_start;
295 if (netif_xmit_stopped(txq) &&
296 time_after(jiffies, (trans_start +
297 dev->watchdog_timeo))) {
298 some_queue_timedout = 1;
299 txq->trans_timeout++;
300 break;
301 }
302 }
303
304 if (some_queue_timedout) {
305 WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",
306 dev->name, netdev_drivername(dev), i);
307 dev->netdev_ops->ndo_tx_timeout(dev);
308 }
309 if (!mod_timer(&dev->watchdog_timer,
310 round_jiffies(jiffies +
311 dev->watchdog_timeo)))
312 dev_hold(dev);
313 }
314 }
315 netif_tx_unlock(dev);
316
317 dev_put(dev);
318}
319
320void __netdev_watchdog_up(struct net_device *dev)
321{
322 if (dev->netdev_ops->ndo_tx_timeout) {
323 if (dev->watchdog_timeo <= 0)
324 dev->watchdog_timeo = 5*HZ;
325 if (!mod_timer(&dev->watchdog_timer,
326 round_jiffies(jiffies + dev->watchdog_timeo)))
327 dev_hold(dev);
328 }
329}
330
331static void dev_watchdog_up(struct net_device *dev)
332{
333 __netdev_watchdog_up(dev);
334}
335
336static void dev_watchdog_down(struct net_device *dev)
337{
338 netif_tx_lock_bh(dev);
339 if (del_timer(&dev->watchdog_timer))
340 dev_put(dev);
341 netif_tx_unlock_bh(dev);
342}
343
344/**
345 * netif_carrier_on - set carrier
346 * @dev: network device
347 *
348 * Device has detected that carrier.
349 */
350void netif_carrier_on(struct net_device *dev)
351{
352 if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
353 if (dev->reg_state == NETREG_UNINITIALIZED)
354 return;
355 atomic_inc(&dev->carrier_changes);
356 linkwatch_fire_event(dev);
357 if (netif_running(dev))
358 __netdev_watchdog_up(dev);
359 }
360}
361EXPORT_SYMBOL(netif_carrier_on);
362
363/**
364 * netif_carrier_off - clear carrier
365 * @dev: network device
366 *
367 * Device has detected loss of carrier.
368 */
369void netif_carrier_off(struct net_device *dev)
370{
371 if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
372 if (dev->reg_state == NETREG_UNINITIALIZED)
373 return;
374 atomic_inc(&dev->carrier_changes);
375 linkwatch_fire_event(dev);
376 }
377}
378EXPORT_SYMBOL(netif_carrier_off);
379
380/* "NOOP" scheduler: the best scheduler, recommended for all interfaces
381 under all circumstances. It is difficult to invent anything faster or
382 cheaper.
383 */
384
385static int noop_enqueue(struct sk_buff *skb, struct Qdisc *qdisc)
386{
387 kfree_skb(skb);
388 return NET_XMIT_CN;
389}
390
391static struct sk_buff *noop_dequeue(struct Qdisc *qdisc)
392{
393 return NULL;
394}
395
396struct Qdisc_ops noop_qdisc_ops __read_mostly = {
397 .id = "noop",
398 .priv_size = 0,
399 .enqueue = noop_enqueue,
400 .dequeue = noop_dequeue,
401 .peek = noop_dequeue,
402 .owner = THIS_MODULE,
403};
404
405static struct netdev_queue noop_netdev_queue = {
406 .qdisc = &noop_qdisc,
407 .qdisc_sleeping = &noop_qdisc,
408};
409
410struct Qdisc noop_qdisc = {
411 .enqueue = noop_enqueue,
412 .dequeue = noop_dequeue,
413 .flags = TCQ_F_BUILTIN,
414 .ops = &noop_qdisc_ops,
415 .list = LIST_HEAD_INIT(noop_qdisc.list),
416 .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
417 .dev_queue = &noop_netdev_queue,
418 .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
419};
420EXPORT_SYMBOL(noop_qdisc);
421
422static int noqueue_init(struct Qdisc *qdisc, struct nlattr *opt)
423{
424 /* register_qdisc() assigns a default of noop_enqueue if unset,
425 * but __dev_queue_xmit() treats noqueue only as such
426 * if this is NULL - so clear it here. */
427 qdisc->enqueue = NULL;
428 return 0;
429}
430
431struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
432 .id = "noqueue",
433 .priv_size = 0,
434 .init = noqueue_init,
435 .enqueue = noop_enqueue,
436 .dequeue = noop_dequeue,
437 .peek = noop_dequeue,
438 .owner = THIS_MODULE,
439};
440
441static const u8 prio2band[TC_PRIO_MAX + 1] = {
442 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1
443};
444
445/* 3-band FIFO queue: old style, but should be a bit faster than
446 generic prio+fifo combination.
447 */
448
449#define PFIFO_FAST_BANDS 3
450
451/*
452 * Private data for a pfifo_fast scheduler containing:
453 * - queues for the three band
454 * - bitmap indicating which of the bands contain skbs
455 */
456struct pfifo_fast_priv {
457 u32 bitmap;
458 struct sk_buff_head q[PFIFO_FAST_BANDS];
459};
460
461/*
462 * Convert a bitmap to the first band number where an skb is queued, where:
463 * bitmap=0 means there are no skbs on any band.
464 * bitmap=1 means there is an skb on band 0.
465 * bitmap=7 means there are skbs on all 3 bands, etc.
466 */
467static const int bitmap2band[] = {-1, 0, 1, 0, 2, 0, 1, 0};
468
469static inline struct sk_buff_head *band2list(struct pfifo_fast_priv *priv,
470 int band)
471{
472 return priv->q + band;
473}
474
475static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc)
476{
477 if (skb_queue_len(&qdisc->q) < qdisc_dev(qdisc)->tx_queue_len) {
478 int band = prio2band[skb->priority & TC_PRIO_MAX];
479 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
480 struct sk_buff_head *list = band2list(priv, band);
481
482 priv->bitmap |= (1 << band);
483 qdisc->q.qlen++;
484 return __qdisc_enqueue_tail(skb, qdisc, list);
485 }
486
487 return qdisc_drop(skb, qdisc);
488}
489
490static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
491{
492 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
493 int band = bitmap2band[priv->bitmap];
494
495 if (likely(band >= 0)) {
496 struct sk_buff_head *list = band2list(priv, band);
497 struct sk_buff *skb = __qdisc_dequeue_head(qdisc, list);
498
499 qdisc->q.qlen--;
500 if (skb_queue_empty(list))
501 priv->bitmap &= ~(1 << band);
502
503 return skb;
504 }
505
506 return NULL;
507}
508
509static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
510{
511 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
512 int band = bitmap2band[priv->bitmap];
513
514 if (band >= 0) {
515 struct sk_buff_head *list = band2list(priv, band);
516
517 return skb_peek(list);
518 }
519
520 return NULL;
521}
522
523static void pfifo_fast_reset(struct Qdisc *qdisc)
524{
525 int prio;
526 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
527
528 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
529 __qdisc_reset_queue(qdisc, band2list(priv, prio));
530
531 priv->bitmap = 0;
532 qdisc->qstats.backlog = 0;
533 qdisc->q.qlen = 0;
534}
535
536static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
537{
538 struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
539
540 memcpy(&opt.priomap, prio2band, TC_PRIO_MAX + 1);
541 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
542 goto nla_put_failure;
543 return skb->len;
544
545nla_put_failure:
546 return -1;
547}
548
549static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt)
550{
551 int prio;
552 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
553
554 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
555 __skb_queue_head_init(band2list(priv, prio));
556
557 /* Can by-pass the queue discipline */
558 qdisc->flags |= TCQ_F_CAN_BYPASS;
559 return 0;
560}
561
562struct Qdisc_ops pfifo_fast_ops __read_mostly = {
563 .id = "pfifo_fast",
564 .priv_size = sizeof(struct pfifo_fast_priv),
565 .enqueue = pfifo_fast_enqueue,
566 .dequeue = pfifo_fast_dequeue,
567 .peek = pfifo_fast_peek,
568 .init = pfifo_fast_init,
569 .reset = pfifo_fast_reset,
570 .dump = pfifo_fast_dump,
571 .owner = THIS_MODULE,
572};
573EXPORT_SYMBOL(pfifo_fast_ops);
574
575static struct lock_class_key qdisc_tx_busylock;
576
577struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
578 const struct Qdisc_ops *ops)
579{
580 void *p;
581 struct Qdisc *sch;
582 unsigned int size = QDISC_ALIGN(sizeof(*sch)) + ops->priv_size;
583 int err = -ENOBUFS;
584 struct net_device *dev = dev_queue->dev;
585
586 p = kzalloc_node(size, GFP_KERNEL,
587 netdev_queue_numa_node_read(dev_queue));
588
589 if (!p)
590 goto errout;
591 sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
592 /* if we got non aligned memory, ask more and do alignment ourself */
593 if (sch != p) {
594 kfree(p);
595 p = kzalloc_node(size + QDISC_ALIGNTO - 1, GFP_KERNEL,
596 netdev_queue_numa_node_read(dev_queue));
597 if (!p)
598 goto errout;
599 sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
600 sch->padded = (char *) sch - (char *) p;
601 }
602 INIT_LIST_HEAD(&sch->list);
603 skb_queue_head_init(&sch->q);
604
605 spin_lock_init(&sch->busylock);
606 lockdep_set_class(&sch->busylock,
607 dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
608
609 sch->ops = ops;
610 sch->enqueue = ops->enqueue;
611 sch->dequeue = ops->dequeue;
612 sch->dev_queue = dev_queue;
613 dev_hold(dev);
614 atomic_set(&sch->refcnt, 1);
615
616 return sch;
617errout:
618 return ERR_PTR(err);
619}
620
621struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
622 const struct Qdisc_ops *ops,
623 unsigned int parentid)
624{
625 struct Qdisc *sch;
626
627 if (!try_module_get(ops->owner))
628 goto errout;
629
630 sch = qdisc_alloc(dev_queue, ops);
631 if (IS_ERR(sch))
632 goto errout;
633 sch->parent = parentid;
634
635 if (!ops->init || ops->init(sch, NULL) == 0)
636 return sch;
637
638 qdisc_destroy(sch);
639errout:
640 return NULL;
641}
642EXPORT_SYMBOL(qdisc_create_dflt);
643
644/* Under qdisc_lock(qdisc) and BH! */
645
646void qdisc_reset(struct Qdisc *qdisc)
647{
648 const struct Qdisc_ops *ops = qdisc->ops;
649
650 if (ops->reset)
651 ops->reset(qdisc);
652
653 if (qdisc->gso_skb) {
654 kfree_skb_list(qdisc->gso_skb);
655 qdisc->gso_skb = NULL;
656 qdisc->q.qlen = 0;
657 }
658}
659EXPORT_SYMBOL(qdisc_reset);
660
661static void qdisc_rcu_free(struct rcu_head *head)
662{
663 struct Qdisc *qdisc = container_of(head, struct Qdisc, rcu_head);
664
665 if (qdisc_is_percpu_stats(qdisc)) {
666 free_percpu(qdisc->cpu_bstats);
667 free_percpu(qdisc->cpu_qstats);
668 }
669
670 kfree((char *) qdisc - qdisc->padded);
671}
672
673void qdisc_destroy(struct Qdisc *qdisc)
674{
675 const struct Qdisc_ops *ops = qdisc->ops;
676
677 if (qdisc->flags & TCQ_F_BUILTIN ||
678 !atomic_dec_and_test(&qdisc->refcnt))
679 return;
680
681#ifdef CONFIG_NET_SCHED
682 qdisc_list_del(qdisc);
683
684 qdisc_put_stab(rtnl_dereference(qdisc->stab));
685#endif
686 gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est);
687 if (ops->reset)
688 ops->reset(qdisc);
689 if (ops->destroy)
690 ops->destroy(qdisc);
691
692 module_put(ops->owner);
693 dev_put(qdisc_dev(qdisc));
694
695 kfree_skb_list(qdisc->gso_skb);
696 /*
697 * gen_estimator est_timer() might access qdisc->q.lock,
698 * wait a RCU grace period before freeing qdisc.
699 */
700 call_rcu(&qdisc->rcu_head, qdisc_rcu_free);
701}
702EXPORT_SYMBOL(qdisc_destroy);
703
704/* Attach toplevel qdisc to device queue. */
705struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
706 struct Qdisc *qdisc)
707{
708 struct Qdisc *oqdisc = dev_queue->qdisc_sleeping;
709 spinlock_t *root_lock;
710
711 root_lock = qdisc_lock(oqdisc);
712 spin_lock_bh(root_lock);
713
714 /* Prune old scheduler */
715 if (oqdisc && atomic_read(&oqdisc->refcnt) <= 1)
716 qdisc_reset(oqdisc);
717
718 /* ... and graft new one */
719 if (qdisc == NULL)
720 qdisc = &noop_qdisc;
721 dev_queue->qdisc_sleeping = qdisc;
722 rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
723
724 spin_unlock_bh(root_lock);
725
726 return oqdisc;
727}
728EXPORT_SYMBOL(dev_graft_qdisc);
729
730static void attach_one_default_qdisc(struct net_device *dev,
731 struct netdev_queue *dev_queue,
732 void *_unused)
733{
734 struct Qdisc *qdisc;
735 const struct Qdisc_ops *ops = default_qdisc_ops;
736
737 if (dev->priv_flags & IFF_NO_QUEUE)
738 ops = &noqueue_qdisc_ops;
739
740 qdisc = qdisc_create_dflt(dev_queue, ops, TC_H_ROOT);
741 if (!qdisc) {
742 netdev_info(dev, "activation failed\n");
743 return;
744 }
745 if (!netif_is_multiqueue(dev))
746 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
747 dev_queue->qdisc_sleeping = qdisc;
748}
749
750static void attach_default_qdiscs(struct net_device *dev)
751{
752 struct netdev_queue *txq;
753 struct Qdisc *qdisc;
754
755 txq = netdev_get_tx_queue(dev, 0);
756
757 if (!netif_is_multiqueue(dev) ||
758 dev->priv_flags & IFF_NO_QUEUE) {
759 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
760 dev->qdisc = txq->qdisc_sleeping;
761 atomic_inc(&dev->qdisc->refcnt);
762 } else {
763 qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT);
764 if (qdisc) {
765 dev->qdisc = qdisc;
766 qdisc->ops->attach(qdisc);
767 }
768 }
769}
770
771static void transition_one_qdisc(struct net_device *dev,
772 struct netdev_queue *dev_queue,
773 void *_need_watchdog)
774{
775 struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
776 int *need_watchdog_p = _need_watchdog;
777
778 if (!(new_qdisc->flags & TCQ_F_BUILTIN))
779 clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
780
781 rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
782 if (need_watchdog_p) {
783 dev_queue->trans_start = 0;
784 *need_watchdog_p = 1;
785 }
786}
787
788void dev_activate(struct net_device *dev)
789{
790 int need_watchdog;
791
792 /* No queueing discipline is attached to device;
793 * create default one for devices, which need queueing
794 * and noqueue_qdisc for virtual interfaces
795 */
796
797 if (dev->qdisc == &noop_qdisc)
798 attach_default_qdiscs(dev);
799
800 if (!netif_carrier_ok(dev))
801 /* Delay activation until next carrier-on event */
802 return;
803
804 need_watchdog = 0;
805 netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
806 if (dev_ingress_queue(dev))
807 transition_one_qdisc(dev, dev_ingress_queue(dev), NULL);
808
809 if (need_watchdog) {
810 dev->trans_start = jiffies;
811 dev_watchdog_up(dev);
812 }
813}
814EXPORT_SYMBOL(dev_activate);
815
816static void dev_deactivate_queue(struct net_device *dev,
817 struct netdev_queue *dev_queue,
818 void *_qdisc_default)
819{
820 struct Qdisc *qdisc_default = _qdisc_default;
821 struct Qdisc *qdisc;
822
823 qdisc = rtnl_dereference(dev_queue->qdisc);
824 if (qdisc) {
825 spin_lock_bh(qdisc_lock(qdisc));
826
827 if (!(qdisc->flags & TCQ_F_BUILTIN))
828 set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
829
830 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
831 qdisc_reset(qdisc);
832
833 spin_unlock_bh(qdisc_lock(qdisc));
834 }
835}
836
837static bool some_qdisc_is_busy(struct net_device *dev)
838{
839 unsigned int i;
840
841 for (i = 0; i < dev->num_tx_queues; i++) {
842 struct netdev_queue *dev_queue;
843 spinlock_t *root_lock;
844 struct Qdisc *q;
845 int val;
846
847 dev_queue = netdev_get_tx_queue(dev, i);
848 q = dev_queue->qdisc_sleeping;
849 root_lock = qdisc_lock(q);
850
851 spin_lock_bh(root_lock);
852
853 val = (qdisc_is_running(q) ||
854 test_bit(__QDISC_STATE_SCHED, &q->state));
855
856 spin_unlock_bh(root_lock);
857
858 if (val)
859 return true;
860 }
861 return false;
862}
863
864/**
865 * dev_deactivate_many - deactivate transmissions on several devices
866 * @head: list of devices to deactivate
867 *
868 * This function returns only when all outstanding transmissions
869 * have completed, unless all devices are in dismantle phase.
870 */
871void dev_deactivate_many(struct list_head *head)
872{
873 struct net_device *dev;
874 bool sync_needed = false;
875
876 list_for_each_entry(dev, head, close_list) {
877 netdev_for_each_tx_queue(dev, dev_deactivate_queue,
878 &noop_qdisc);
879 if (dev_ingress_queue(dev))
880 dev_deactivate_queue(dev, dev_ingress_queue(dev),
881 &noop_qdisc);
882
883 dev_watchdog_down(dev);
884 sync_needed |= !dev->dismantle;
885 }
886
887 /* Wait for outstanding qdisc-less dev_queue_xmit calls.
888 * This is avoided if all devices are in dismantle phase :
889 * Caller will call synchronize_net() for us
890 */
891 if (sync_needed)
892 synchronize_net();
893
894 /* Wait for outstanding qdisc_run calls. */
895 list_for_each_entry(dev, head, close_list)
896 while (some_qdisc_is_busy(dev))
897 yield();
898}
899
900void dev_deactivate(struct net_device *dev)
901{
902 LIST_HEAD(single);
903
904 list_add(&dev->close_list, &single);
905 dev_deactivate_many(&single);
906 list_del(&single);
907}
908EXPORT_SYMBOL(dev_deactivate);
909
910static void dev_init_scheduler_queue(struct net_device *dev,
911 struct netdev_queue *dev_queue,
912 void *_qdisc)
913{
914 struct Qdisc *qdisc = _qdisc;
915
916 rcu_assign_pointer(dev_queue->qdisc, qdisc);
917 dev_queue->qdisc_sleeping = qdisc;
918}
919
920void dev_init_scheduler(struct net_device *dev)
921{
922 dev->qdisc = &noop_qdisc;
923 netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
924 if (dev_ingress_queue(dev))
925 dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
926
927 setup_timer(&dev->watchdog_timer, dev_watchdog, (unsigned long)dev);
928}
929
930static void shutdown_scheduler_queue(struct net_device *dev,
931 struct netdev_queue *dev_queue,
932 void *_qdisc_default)
933{
934 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
935 struct Qdisc *qdisc_default = _qdisc_default;
936
937 if (qdisc) {
938 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
939 dev_queue->qdisc_sleeping = qdisc_default;
940
941 qdisc_destroy(qdisc);
942 }
943}
944
945void dev_shutdown(struct net_device *dev)
946{
947 netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
948 if (dev_ingress_queue(dev))
949 shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
950 qdisc_destroy(dev->qdisc);
951 dev->qdisc = &noop_qdisc;
952
953 WARN_ON(timer_pending(&dev->watchdog_timer));
954}
955
956void psched_ratecfg_precompute(struct psched_ratecfg *r,
957 const struct tc_ratespec *conf,
958 u64 rate64)
959{
960 memset(r, 0, sizeof(*r));
961 r->overhead = conf->overhead;
962 r->rate_bytes_ps = max_t(u64, conf->rate, rate64);
963 r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK);
964 r->mult = 1;
965 /*
966 * The deal here is to replace a divide by a reciprocal one
967 * in fast path (a reciprocal divide is a multiply and a shift)
968 *
969 * Normal formula would be :
970 * time_in_ns = (NSEC_PER_SEC * len) / rate_bps
971 *
972 * We compute mult/shift to use instead :
973 * time_in_ns = (len * mult) >> shift;
974 *
975 * We try to get the highest possible mult value for accuracy,
976 * but have to make sure no overflows will ever happen.
977 */
978 if (r->rate_bytes_ps > 0) {
979 u64 factor = NSEC_PER_SEC;
980
981 for (;;) {
982 r->mult = div64_u64(factor, r->rate_bytes_ps);
983 if (r->mult & (1U << 31) || factor & (1ULL << 63))
984 break;
985 factor <<= 1;
986 r->shift++;
987 }
988 }
989}
990EXPORT_SYMBOL(psched_ratecfg_precompute);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/sch_generic.c Generic packet scheduler routines.
4 *
5 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6 * Jamal Hadi Salim, <hadi@cyberus.ca> 990601
7 * - Ingress support
8 */
9
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>
29#include <net/dst.h>
30#include <trace/events/qdisc.h>
31#include <trace/events/net.h>
32#include <net/xfrm.h>
33
34/* Qdisc to use by default */
35const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops;
36EXPORT_SYMBOL(default_qdisc_ops);
37
38static void qdisc_maybe_clear_missed(struct Qdisc *q,
39 const struct netdev_queue *txq)
40{
41 clear_bit(__QDISC_STATE_MISSED, &q->state);
42
43 /* Make sure the below netif_xmit_frozen_or_stopped()
44 * checking happens after clearing STATE_MISSED.
45 */
46 smp_mb__after_atomic();
47
48 /* Checking netif_xmit_frozen_or_stopped() again to
49 * make sure STATE_MISSED is set if the STATE_MISSED
50 * set by netif_tx_wake_queue()'s rescheduling of
51 * net_tx_action() is cleared by the above clear_bit().
52 */
53 if (!netif_xmit_frozen_or_stopped(txq))
54 set_bit(__QDISC_STATE_MISSED, &q->state);
55 else
56 set_bit(__QDISC_STATE_DRAINING, &q->state);
57}
58
59/* Main transmission queue. */
60
61/* Modifications to data participating in scheduling must be protected with
62 * qdisc_lock(qdisc) spinlock.
63 *
64 * The idea is the following:
65 * - enqueue, dequeue are serialized via qdisc root lock
66 * - ingress filtering is also serialized via qdisc root lock
67 * - updates to tree and tree walking are only done under the rtnl mutex.
68 */
69
70#define SKB_XOFF_MAGIC ((struct sk_buff *)1UL)
71
72static inline struct sk_buff *__skb_dequeue_bad_txq(struct Qdisc *q)
73{
74 const struct netdev_queue *txq = q->dev_queue;
75 spinlock_t *lock = NULL;
76 struct sk_buff *skb;
77
78 if (q->flags & TCQ_F_NOLOCK) {
79 lock = qdisc_lock(q);
80 spin_lock(lock);
81 }
82
83 skb = skb_peek(&q->skb_bad_txq);
84 if (skb) {
85 /* check the reason of requeuing without tx lock first */
86 txq = skb_get_tx_queue(txq->dev, skb);
87 if (!netif_xmit_frozen_or_stopped(txq)) {
88 skb = __skb_dequeue(&q->skb_bad_txq);
89 if (qdisc_is_percpu_stats(q)) {
90 qdisc_qstats_cpu_backlog_dec(q, skb);
91 qdisc_qstats_cpu_qlen_dec(q);
92 } else {
93 qdisc_qstats_backlog_dec(q, skb);
94 q->q.qlen--;
95 }
96 } else {
97 skb = SKB_XOFF_MAGIC;
98 qdisc_maybe_clear_missed(q, txq);
99 }
100 }
101
102 if (lock)
103 spin_unlock(lock);
104
105 return skb;
106}
107
108static inline struct sk_buff *qdisc_dequeue_skb_bad_txq(struct Qdisc *q)
109{
110 struct sk_buff *skb = skb_peek(&q->skb_bad_txq);
111
112 if (unlikely(skb))
113 skb = __skb_dequeue_bad_txq(q);
114
115 return skb;
116}
117
118static inline void qdisc_enqueue_skb_bad_txq(struct Qdisc *q,
119 struct sk_buff *skb)
120{
121 spinlock_t *lock = NULL;
122
123 if (q->flags & TCQ_F_NOLOCK) {
124 lock = qdisc_lock(q);
125 spin_lock(lock);
126 }
127
128 __skb_queue_tail(&q->skb_bad_txq, skb);
129
130 if (qdisc_is_percpu_stats(q)) {
131 qdisc_qstats_cpu_backlog_inc(q, skb);
132 qdisc_qstats_cpu_qlen_inc(q);
133 } else {
134 qdisc_qstats_backlog_inc(q, skb);
135 q->q.qlen++;
136 }
137
138 if (lock)
139 spin_unlock(lock);
140}
141
142static inline void dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
143{
144 spinlock_t *lock = NULL;
145
146 if (q->flags & TCQ_F_NOLOCK) {
147 lock = qdisc_lock(q);
148 spin_lock(lock);
149 }
150
151 while (skb) {
152 struct sk_buff *next = skb->next;
153
154 __skb_queue_tail(&q->gso_skb, skb);
155
156 /* it's still part of the queue */
157 if (qdisc_is_percpu_stats(q)) {
158 qdisc_qstats_cpu_requeues_inc(q);
159 qdisc_qstats_cpu_backlog_inc(q, skb);
160 qdisc_qstats_cpu_qlen_inc(q);
161 } else {
162 q->qstats.requeues++;
163 qdisc_qstats_backlog_inc(q, skb);
164 q->q.qlen++;
165 }
166
167 skb = next;
168 }
169
170 if (lock) {
171 spin_unlock(lock);
172 set_bit(__QDISC_STATE_MISSED, &q->state);
173 } else {
174 __netif_schedule(q);
175 }
176}
177
178static void try_bulk_dequeue_skb(struct Qdisc *q,
179 struct sk_buff *skb,
180 const struct netdev_queue *txq,
181 int *packets)
182{
183 int bytelimit = qdisc_avail_bulklimit(txq) - skb->len;
184
185 while (bytelimit > 0) {
186 struct sk_buff *nskb = q->dequeue(q);
187
188 if (!nskb)
189 break;
190
191 bytelimit -= nskb->len; /* covers GSO len */
192 skb->next = nskb;
193 skb = nskb;
194 (*packets)++; /* GSO counts as one pkt */
195 }
196 skb_mark_not_on_list(skb);
197}
198
199/* This variant of try_bulk_dequeue_skb() makes sure
200 * all skbs in the chain are for the same txq
201 */
202static void try_bulk_dequeue_skb_slow(struct Qdisc *q,
203 struct sk_buff *skb,
204 int *packets)
205{
206 int mapping = skb_get_queue_mapping(skb);
207 struct sk_buff *nskb;
208 int cnt = 0;
209
210 do {
211 nskb = q->dequeue(q);
212 if (!nskb)
213 break;
214 if (unlikely(skb_get_queue_mapping(nskb) != mapping)) {
215 qdisc_enqueue_skb_bad_txq(q, nskb);
216 break;
217 }
218 skb->next = nskb;
219 skb = nskb;
220 } while (++cnt < 8);
221 (*packets) += cnt;
222 skb_mark_not_on_list(skb);
223}
224
225/* Note that dequeue_skb can possibly return a SKB list (via skb->next).
226 * A requeued skb (via q->gso_skb) can also be a SKB list.
227 */
228static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
229 int *packets)
230{
231 const struct netdev_queue *txq = q->dev_queue;
232 struct sk_buff *skb = NULL;
233
234 *packets = 1;
235 if (unlikely(!skb_queue_empty(&q->gso_skb))) {
236 spinlock_t *lock = NULL;
237
238 if (q->flags & TCQ_F_NOLOCK) {
239 lock = qdisc_lock(q);
240 spin_lock(lock);
241 }
242
243 skb = skb_peek(&q->gso_skb);
244
245 /* skb may be null if another cpu pulls gso_skb off in between
246 * empty check and lock.
247 */
248 if (!skb) {
249 if (lock)
250 spin_unlock(lock);
251 goto validate;
252 }
253
254 /* skb in gso_skb were already validated */
255 *validate = false;
256 if (xfrm_offload(skb))
257 *validate = true;
258 /* check the reason of requeuing without tx lock first */
259 txq = skb_get_tx_queue(txq->dev, skb);
260 if (!netif_xmit_frozen_or_stopped(txq)) {
261 skb = __skb_dequeue(&q->gso_skb);
262 if (qdisc_is_percpu_stats(q)) {
263 qdisc_qstats_cpu_backlog_dec(q, skb);
264 qdisc_qstats_cpu_qlen_dec(q);
265 } else {
266 qdisc_qstats_backlog_dec(q, skb);
267 q->q.qlen--;
268 }
269 } else {
270 skb = NULL;
271 qdisc_maybe_clear_missed(q, txq);
272 }
273 if (lock)
274 spin_unlock(lock);
275 goto trace;
276 }
277validate:
278 *validate = true;
279
280 if ((q->flags & TCQ_F_ONETXQUEUE) &&
281 netif_xmit_frozen_or_stopped(txq)) {
282 qdisc_maybe_clear_missed(q, txq);
283 return skb;
284 }
285
286 skb = qdisc_dequeue_skb_bad_txq(q);
287 if (unlikely(skb)) {
288 if (skb == SKB_XOFF_MAGIC)
289 return NULL;
290 goto bulk;
291 }
292 skb = q->dequeue(q);
293 if (skb) {
294bulk:
295 if (qdisc_may_bulk(q))
296 try_bulk_dequeue_skb(q, skb, txq, packets);
297 else
298 try_bulk_dequeue_skb_slow(q, skb, packets);
299 }
300trace:
301 trace_qdisc_dequeue(q, txq, *packets, skb);
302 return skb;
303}
304
305/*
306 * Transmit possibly several skbs, and handle the return status as
307 * required. Owning running seqcount bit guarantees that
308 * only one CPU can execute this function.
309 *
310 * Returns to the caller:
311 * false - hardware queue frozen backoff
312 * true - feel free to send more pkts
313 */
314bool sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
315 struct net_device *dev, struct netdev_queue *txq,
316 spinlock_t *root_lock, bool validate)
317{
318 int ret = NETDEV_TX_BUSY;
319 bool again = false;
320
321 /* And release qdisc */
322 if (root_lock)
323 spin_unlock(root_lock);
324
325 /* Note that we validate skb (GSO, checksum, ...) outside of locks */
326 if (validate)
327 skb = validate_xmit_skb_list(skb, dev, &again);
328
329#ifdef CONFIG_XFRM_OFFLOAD
330 if (unlikely(again)) {
331 if (root_lock)
332 spin_lock(root_lock);
333
334 dev_requeue_skb(skb, q);
335 return false;
336 }
337#endif
338
339 if (likely(skb)) {
340 HARD_TX_LOCK(dev, txq, smp_processor_id());
341 if (!netif_xmit_frozen_or_stopped(txq))
342 skb = dev_hard_start_xmit(skb, dev, txq, &ret);
343 else
344 qdisc_maybe_clear_missed(q, txq);
345
346 HARD_TX_UNLOCK(dev, txq);
347 } else {
348 if (root_lock)
349 spin_lock(root_lock);
350 return true;
351 }
352
353 if (root_lock)
354 spin_lock(root_lock);
355
356 if (!dev_xmit_complete(ret)) {
357 /* Driver returned NETDEV_TX_BUSY - requeue skb */
358 if (unlikely(ret != NETDEV_TX_BUSY))
359 net_warn_ratelimited("BUG %s code %d qlen %d\n",
360 dev->name, ret, q->q.qlen);
361
362 dev_requeue_skb(skb, q);
363 return false;
364 }
365
366 return true;
367}
368
369/*
370 * NOTE: Called under qdisc_lock(q) with locally disabled BH.
371 *
372 * running seqcount guarantees only one CPU can process
373 * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
374 * this queue.
375 *
376 * netif_tx_lock serializes accesses to device driver.
377 *
378 * qdisc_lock(q) and netif_tx_lock are mutually exclusive,
379 * if one is grabbed, another must be free.
380 *
381 * Note, that this procedure can be called by a watchdog timer
382 *
383 * Returns to the caller:
384 * 0 - queue is empty or throttled.
385 * >0 - queue is not empty.
386 *
387 */
388static inline bool qdisc_restart(struct Qdisc *q, int *packets)
389{
390 spinlock_t *root_lock = NULL;
391 struct netdev_queue *txq;
392 struct net_device *dev;
393 struct sk_buff *skb;
394 bool validate;
395
396 /* Dequeue packet */
397 skb = dequeue_skb(q, &validate, packets);
398 if (unlikely(!skb))
399 return false;
400
401 if (!(q->flags & TCQ_F_NOLOCK))
402 root_lock = qdisc_lock(q);
403
404 dev = qdisc_dev(q);
405 txq = skb_get_tx_queue(dev, skb);
406
407 return sch_direct_xmit(skb, q, dev, txq, root_lock, validate);
408}
409
410void __qdisc_run(struct Qdisc *q)
411{
412 int quota = dev_tx_weight;
413 int packets;
414
415 while (qdisc_restart(q, &packets)) {
416 quota -= packets;
417 if (quota <= 0) {
418 if (q->flags & TCQ_F_NOLOCK)
419 set_bit(__QDISC_STATE_MISSED, &q->state);
420 else
421 __netif_schedule(q);
422
423 break;
424 }
425 }
426}
427
428unsigned long dev_trans_start(struct net_device *dev)
429{
430 unsigned long val, res;
431 unsigned int i;
432
433 if (is_vlan_dev(dev))
434 dev = vlan_dev_real_dev(dev);
435 else if (netif_is_macvlan(dev))
436 dev = macvlan_dev_real_dev(dev);
437 res = netdev_get_tx_queue(dev, 0)->trans_start;
438 for (i = 1; i < dev->num_tx_queues; i++) {
439 val = netdev_get_tx_queue(dev, i)->trans_start;
440 if (val && time_after(val, res))
441 res = val;
442 }
443
444 return res;
445}
446EXPORT_SYMBOL(dev_trans_start);
447
448static void dev_watchdog(struct timer_list *t)
449{
450 struct net_device *dev = from_timer(dev, t, watchdog_timer);
451
452 netif_tx_lock(dev);
453 if (!qdisc_tx_is_noop(dev)) {
454 if (netif_device_present(dev) &&
455 netif_running(dev) &&
456 netif_carrier_ok(dev)) {
457 int some_queue_timedout = 0;
458 unsigned int i;
459 unsigned long trans_start;
460
461 for (i = 0; i < dev->num_tx_queues; i++) {
462 struct netdev_queue *txq;
463
464 txq = netdev_get_tx_queue(dev, i);
465 trans_start = txq->trans_start;
466 if (netif_xmit_stopped(txq) &&
467 time_after(jiffies, (trans_start +
468 dev->watchdog_timeo))) {
469 some_queue_timedout = 1;
470 txq->trans_timeout++;
471 break;
472 }
473 }
474
475 if (some_queue_timedout) {
476 trace_net_dev_xmit_timeout(dev, i);
477 WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",
478 dev->name, netdev_drivername(dev), i);
479 dev->netdev_ops->ndo_tx_timeout(dev, i);
480 }
481 if (!mod_timer(&dev->watchdog_timer,
482 round_jiffies(jiffies +
483 dev->watchdog_timeo)))
484 dev_hold(dev);
485 }
486 }
487 netif_tx_unlock(dev);
488
489 dev_put(dev);
490}
491
492void __netdev_watchdog_up(struct net_device *dev)
493{
494 if (dev->netdev_ops->ndo_tx_timeout) {
495 if (dev->watchdog_timeo <= 0)
496 dev->watchdog_timeo = 5*HZ;
497 if (!mod_timer(&dev->watchdog_timer,
498 round_jiffies(jiffies + dev->watchdog_timeo)))
499 dev_hold(dev);
500 }
501}
502EXPORT_SYMBOL_GPL(__netdev_watchdog_up);
503
504static void dev_watchdog_up(struct net_device *dev)
505{
506 __netdev_watchdog_up(dev);
507}
508
509static void dev_watchdog_down(struct net_device *dev)
510{
511 netif_tx_lock_bh(dev);
512 if (del_timer(&dev->watchdog_timer))
513 dev_put(dev);
514 netif_tx_unlock_bh(dev);
515}
516
517/**
518 * netif_carrier_on - set carrier
519 * @dev: network device
520 *
521 * Device has detected acquisition of carrier.
522 */
523void netif_carrier_on(struct net_device *dev)
524{
525 if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
526 if (dev->reg_state == NETREG_UNINITIALIZED)
527 return;
528 atomic_inc(&dev->carrier_up_count);
529 linkwatch_fire_event(dev);
530 if (netif_running(dev))
531 __netdev_watchdog_up(dev);
532 }
533}
534EXPORT_SYMBOL(netif_carrier_on);
535
536/**
537 * netif_carrier_off - clear carrier
538 * @dev: network device
539 *
540 * Device has detected loss of carrier.
541 */
542void netif_carrier_off(struct net_device *dev)
543{
544 if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
545 if (dev->reg_state == NETREG_UNINITIALIZED)
546 return;
547 atomic_inc(&dev->carrier_down_count);
548 linkwatch_fire_event(dev);
549 }
550}
551EXPORT_SYMBOL(netif_carrier_off);
552
553/**
554 * netif_carrier_event - report carrier state event
555 * @dev: network device
556 *
557 * Device has detected a carrier event but the carrier state wasn't changed.
558 * Use in drivers when querying carrier state asynchronously, to avoid missing
559 * events (link flaps) if link recovers before it's queried.
560 */
561void netif_carrier_event(struct net_device *dev)
562{
563 if (dev->reg_state == NETREG_UNINITIALIZED)
564 return;
565 atomic_inc(&dev->carrier_up_count);
566 atomic_inc(&dev->carrier_down_count);
567 linkwatch_fire_event(dev);
568}
569EXPORT_SYMBOL_GPL(netif_carrier_event);
570
571/* "NOOP" scheduler: the best scheduler, recommended for all interfaces
572 under all circumstances. It is difficult to invent anything faster or
573 cheaper.
574 */
575
576static int noop_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
577 struct sk_buff **to_free)
578{
579 __qdisc_drop(skb, to_free);
580 return NET_XMIT_CN;
581}
582
583static struct sk_buff *noop_dequeue(struct Qdisc *qdisc)
584{
585 return NULL;
586}
587
588struct Qdisc_ops noop_qdisc_ops __read_mostly = {
589 .id = "noop",
590 .priv_size = 0,
591 .enqueue = noop_enqueue,
592 .dequeue = noop_dequeue,
593 .peek = noop_dequeue,
594 .owner = THIS_MODULE,
595};
596
597static struct netdev_queue noop_netdev_queue = {
598 RCU_POINTER_INITIALIZER(qdisc, &noop_qdisc),
599 .qdisc_sleeping = &noop_qdisc,
600};
601
602struct Qdisc noop_qdisc = {
603 .enqueue = noop_enqueue,
604 .dequeue = noop_dequeue,
605 .flags = TCQ_F_BUILTIN,
606 .ops = &noop_qdisc_ops,
607 .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
608 .dev_queue = &noop_netdev_queue,
609 .running = SEQCNT_ZERO(noop_qdisc.running),
610 .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
611 .gso_skb = {
612 .next = (struct sk_buff *)&noop_qdisc.gso_skb,
613 .prev = (struct sk_buff *)&noop_qdisc.gso_skb,
614 .qlen = 0,
615 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.gso_skb.lock),
616 },
617 .skb_bad_txq = {
618 .next = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
619 .prev = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
620 .qlen = 0,
621 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.skb_bad_txq.lock),
622 },
623};
624EXPORT_SYMBOL(noop_qdisc);
625
626static int noqueue_init(struct Qdisc *qdisc, struct nlattr *opt,
627 struct netlink_ext_ack *extack)
628{
629 /* register_qdisc() assigns a default of noop_enqueue if unset,
630 * but __dev_queue_xmit() treats noqueue only as such
631 * if this is NULL - so clear it here. */
632 qdisc->enqueue = NULL;
633 return 0;
634}
635
636struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
637 .id = "noqueue",
638 .priv_size = 0,
639 .init = noqueue_init,
640 .enqueue = noop_enqueue,
641 .dequeue = noop_dequeue,
642 .peek = noop_dequeue,
643 .owner = THIS_MODULE,
644};
645
646static const u8 prio2band[TC_PRIO_MAX + 1] = {
647 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1
648};
649
650/* 3-band FIFO queue: old style, but should be a bit faster than
651 generic prio+fifo combination.
652 */
653
654#define PFIFO_FAST_BANDS 3
655
656/*
657 * Private data for a pfifo_fast scheduler containing:
658 * - rings for priority bands
659 */
660struct pfifo_fast_priv {
661 struct skb_array q[PFIFO_FAST_BANDS];
662};
663
664static inline struct skb_array *band2list(struct pfifo_fast_priv *priv,
665 int band)
666{
667 return &priv->q[band];
668}
669
670static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
671 struct sk_buff **to_free)
672{
673 int band = prio2band[skb->priority & TC_PRIO_MAX];
674 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
675 struct skb_array *q = band2list(priv, band);
676 unsigned int pkt_len = qdisc_pkt_len(skb);
677 int err;
678
679 err = skb_array_produce(q, skb);
680
681 if (unlikely(err)) {
682 if (qdisc_is_percpu_stats(qdisc))
683 return qdisc_drop_cpu(skb, qdisc, to_free);
684 else
685 return qdisc_drop(skb, qdisc, to_free);
686 }
687
688 qdisc_update_stats_at_enqueue(qdisc, pkt_len);
689 return NET_XMIT_SUCCESS;
690}
691
692static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
693{
694 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
695 struct sk_buff *skb = NULL;
696 bool need_retry = true;
697 int band;
698
699retry:
700 for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
701 struct skb_array *q = band2list(priv, band);
702
703 if (__skb_array_empty(q))
704 continue;
705
706 skb = __skb_array_consume(q);
707 }
708 if (likely(skb)) {
709 qdisc_update_stats_at_dequeue(qdisc, skb);
710 } else if (need_retry &&
711 READ_ONCE(qdisc->state) & QDISC_STATE_NON_EMPTY) {
712 /* Delay clearing the STATE_MISSED here to reduce
713 * the overhead of the second spin_trylock() in
714 * qdisc_run_begin() and __netif_schedule() calling
715 * in qdisc_run_end().
716 */
717 clear_bit(__QDISC_STATE_MISSED, &qdisc->state);
718 clear_bit(__QDISC_STATE_DRAINING, &qdisc->state);
719
720 /* Make sure dequeuing happens after clearing
721 * STATE_MISSED.
722 */
723 smp_mb__after_atomic();
724
725 need_retry = false;
726
727 goto retry;
728 }
729
730 return skb;
731}
732
733static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
734{
735 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
736 struct sk_buff *skb = NULL;
737 int band;
738
739 for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
740 struct skb_array *q = band2list(priv, band);
741
742 skb = __skb_array_peek(q);
743 }
744
745 return skb;
746}
747
748static void pfifo_fast_reset(struct Qdisc *qdisc)
749{
750 int i, band;
751 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
752
753 for (band = 0; band < PFIFO_FAST_BANDS; band++) {
754 struct skb_array *q = band2list(priv, band);
755 struct sk_buff *skb;
756
757 /* NULL ring is possible if destroy path is due to a failed
758 * skb_array_init() in pfifo_fast_init() case.
759 */
760 if (!q->ring.queue)
761 continue;
762
763 while ((skb = __skb_array_consume(q)) != NULL)
764 kfree_skb(skb);
765 }
766
767 if (qdisc_is_percpu_stats(qdisc)) {
768 for_each_possible_cpu(i) {
769 struct gnet_stats_queue *q;
770
771 q = per_cpu_ptr(qdisc->cpu_qstats, i);
772 q->backlog = 0;
773 q->qlen = 0;
774 }
775 }
776}
777
778static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
779{
780 struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
781
782 memcpy(&opt.priomap, prio2band, TC_PRIO_MAX + 1);
783 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
784 goto nla_put_failure;
785 return skb->len;
786
787nla_put_failure:
788 return -1;
789}
790
791static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt,
792 struct netlink_ext_ack *extack)
793{
794 unsigned int qlen = qdisc_dev(qdisc)->tx_queue_len;
795 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
796 int prio;
797
798 /* guard against zero length rings */
799 if (!qlen)
800 return -EINVAL;
801
802 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
803 struct skb_array *q = band2list(priv, prio);
804 int err;
805
806 err = skb_array_init(q, qlen, GFP_KERNEL);
807 if (err)
808 return -ENOMEM;
809 }
810
811 /* Can by-pass the queue discipline */
812 qdisc->flags |= TCQ_F_CAN_BYPASS;
813 return 0;
814}
815
816static void pfifo_fast_destroy(struct Qdisc *sch)
817{
818 struct pfifo_fast_priv *priv = qdisc_priv(sch);
819 int prio;
820
821 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
822 struct skb_array *q = band2list(priv, prio);
823
824 /* NULL ring is possible if destroy path is due to a failed
825 * skb_array_init() in pfifo_fast_init() case.
826 */
827 if (!q->ring.queue)
828 continue;
829 /* Destroy ring but no need to kfree_skb because a call to
830 * pfifo_fast_reset() has already done that work.
831 */
832 ptr_ring_cleanup(&q->ring, NULL);
833 }
834}
835
836static int pfifo_fast_change_tx_queue_len(struct Qdisc *sch,
837 unsigned int new_len)
838{
839 struct pfifo_fast_priv *priv = qdisc_priv(sch);
840 struct skb_array *bands[PFIFO_FAST_BANDS];
841 int prio;
842
843 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
844 struct skb_array *q = band2list(priv, prio);
845
846 bands[prio] = q;
847 }
848
849 return skb_array_resize_multiple(bands, PFIFO_FAST_BANDS, new_len,
850 GFP_KERNEL);
851}
852
853struct Qdisc_ops pfifo_fast_ops __read_mostly = {
854 .id = "pfifo_fast",
855 .priv_size = sizeof(struct pfifo_fast_priv),
856 .enqueue = pfifo_fast_enqueue,
857 .dequeue = pfifo_fast_dequeue,
858 .peek = pfifo_fast_peek,
859 .init = pfifo_fast_init,
860 .destroy = pfifo_fast_destroy,
861 .reset = pfifo_fast_reset,
862 .dump = pfifo_fast_dump,
863 .change_tx_queue_len = pfifo_fast_change_tx_queue_len,
864 .owner = THIS_MODULE,
865 .static_flags = TCQ_F_NOLOCK | TCQ_F_CPUSTATS,
866};
867EXPORT_SYMBOL(pfifo_fast_ops);
868
869static struct lock_class_key qdisc_tx_busylock;
870static struct lock_class_key qdisc_running_key;
871
872struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
873 const struct Qdisc_ops *ops,
874 struct netlink_ext_ack *extack)
875{
876 struct Qdisc *sch;
877 unsigned int size = sizeof(*sch) + ops->priv_size;
878 int err = -ENOBUFS;
879 struct net_device *dev;
880
881 if (!dev_queue) {
882 NL_SET_ERR_MSG(extack, "No device queue given");
883 err = -EINVAL;
884 goto errout;
885 }
886
887 dev = dev_queue->dev;
888 sch = kzalloc_node(size, GFP_KERNEL, netdev_queue_numa_node_read(dev_queue));
889
890 if (!sch)
891 goto errout;
892 __skb_queue_head_init(&sch->gso_skb);
893 __skb_queue_head_init(&sch->skb_bad_txq);
894 qdisc_skb_head_init(&sch->q);
895 spin_lock_init(&sch->q.lock);
896
897 if (ops->static_flags & TCQ_F_CPUSTATS) {
898 sch->cpu_bstats =
899 netdev_alloc_pcpu_stats(struct gnet_stats_basic_cpu);
900 if (!sch->cpu_bstats)
901 goto errout1;
902
903 sch->cpu_qstats = alloc_percpu(struct gnet_stats_queue);
904 if (!sch->cpu_qstats) {
905 free_percpu(sch->cpu_bstats);
906 goto errout1;
907 }
908 }
909
910 spin_lock_init(&sch->busylock);
911 lockdep_set_class(&sch->busylock,
912 dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
913
914 /* seqlock has the same scope of busylock, for NOLOCK qdisc */
915 spin_lock_init(&sch->seqlock);
916 lockdep_set_class(&sch->seqlock,
917 dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
918
919 seqcount_init(&sch->running);
920 lockdep_set_class(&sch->running,
921 dev->qdisc_running_key ?: &qdisc_running_key);
922
923 sch->ops = ops;
924 sch->flags = ops->static_flags;
925 sch->enqueue = ops->enqueue;
926 sch->dequeue = ops->dequeue;
927 sch->dev_queue = dev_queue;
928 dev_hold(dev);
929 refcount_set(&sch->refcnt, 1);
930
931 return sch;
932errout1:
933 kfree(sch);
934errout:
935 return ERR_PTR(err);
936}
937
938struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
939 const struct Qdisc_ops *ops,
940 unsigned int parentid,
941 struct netlink_ext_ack *extack)
942{
943 struct Qdisc *sch;
944
945 if (!try_module_get(ops->owner)) {
946 NL_SET_ERR_MSG(extack, "Failed to increase module reference counter");
947 return NULL;
948 }
949
950 sch = qdisc_alloc(dev_queue, ops, extack);
951 if (IS_ERR(sch)) {
952 module_put(ops->owner);
953 return NULL;
954 }
955 sch->parent = parentid;
956
957 if (!ops->init || ops->init(sch, NULL, extack) == 0) {
958 trace_qdisc_create(ops, dev_queue->dev, parentid);
959 return sch;
960 }
961
962 qdisc_put(sch);
963 return NULL;
964}
965EXPORT_SYMBOL(qdisc_create_dflt);
966
967/* Under qdisc_lock(qdisc) and BH! */
968
969void qdisc_reset(struct Qdisc *qdisc)
970{
971 const struct Qdisc_ops *ops = qdisc->ops;
972 struct sk_buff *skb, *tmp;
973
974 trace_qdisc_reset(qdisc);
975
976 if (ops->reset)
977 ops->reset(qdisc);
978
979 skb_queue_walk_safe(&qdisc->gso_skb, skb, tmp) {
980 __skb_unlink(skb, &qdisc->gso_skb);
981 kfree_skb_list(skb);
982 }
983
984 skb_queue_walk_safe(&qdisc->skb_bad_txq, skb, tmp) {
985 __skb_unlink(skb, &qdisc->skb_bad_txq);
986 kfree_skb_list(skb);
987 }
988
989 qdisc->q.qlen = 0;
990 qdisc->qstats.backlog = 0;
991}
992EXPORT_SYMBOL(qdisc_reset);
993
994void qdisc_free(struct Qdisc *qdisc)
995{
996 if (qdisc_is_percpu_stats(qdisc)) {
997 free_percpu(qdisc->cpu_bstats);
998 free_percpu(qdisc->cpu_qstats);
999 }
1000
1001 kfree(qdisc);
1002}
1003
1004static void qdisc_free_cb(struct rcu_head *head)
1005{
1006 struct Qdisc *q = container_of(head, struct Qdisc, rcu);
1007
1008 qdisc_free(q);
1009}
1010
1011static void qdisc_destroy(struct Qdisc *qdisc)
1012{
1013 const struct Qdisc_ops *ops = qdisc->ops;
1014
1015#ifdef CONFIG_NET_SCHED
1016 qdisc_hash_del(qdisc);
1017
1018 qdisc_put_stab(rtnl_dereference(qdisc->stab));
1019#endif
1020 gen_kill_estimator(&qdisc->rate_est);
1021
1022 qdisc_reset(qdisc);
1023
1024 if (ops->destroy)
1025 ops->destroy(qdisc);
1026
1027 module_put(ops->owner);
1028 dev_put(qdisc_dev(qdisc));
1029
1030 trace_qdisc_destroy(qdisc);
1031
1032 call_rcu(&qdisc->rcu, qdisc_free_cb);
1033}
1034
1035void qdisc_put(struct Qdisc *qdisc)
1036{
1037 if (!qdisc)
1038 return;
1039
1040 if (qdisc->flags & TCQ_F_BUILTIN ||
1041 !refcount_dec_and_test(&qdisc->refcnt))
1042 return;
1043
1044 qdisc_destroy(qdisc);
1045}
1046EXPORT_SYMBOL(qdisc_put);
1047
1048/* Version of qdisc_put() that is called with rtnl mutex unlocked.
1049 * Intended to be used as optimization, this function only takes rtnl lock if
1050 * qdisc reference counter reached zero.
1051 */
1052
1053void qdisc_put_unlocked(struct Qdisc *qdisc)
1054{
1055 if (qdisc->flags & TCQ_F_BUILTIN ||
1056 !refcount_dec_and_rtnl_lock(&qdisc->refcnt))
1057 return;
1058
1059 qdisc_destroy(qdisc);
1060 rtnl_unlock();
1061}
1062EXPORT_SYMBOL(qdisc_put_unlocked);
1063
1064/* Attach toplevel qdisc to device queue. */
1065struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
1066 struct Qdisc *qdisc)
1067{
1068 struct Qdisc *oqdisc = dev_queue->qdisc_sleeping;
1069 spinlock_t *root_lock;
1070
1071 root_lock = qdisc_lock(oqdisc);
1072 spin_lock_bh(root_lock);
1073
1074 /* ... and graft new one */
1075 if (qdisc == NULL)
1076 qdisc = &noop_qdisc;
1077 dev_queue->qdisc_sleeping = qdisc;
1078 rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
1079
1080 spin_unlock_bh(root_lock);
1081
1082 return oqdisc;
1083}
1084EXPORT_SYMBOL(dev_graft_qdisc);
1085
1086static void attach_one_default_qdisc(struct net_device *dev,
1087 struct netdev_queue *dev_queue,
1088 void *_unused)
1089{
1090 struct Qdisc *qdisc;
1091 const struct Qdisc_ops *ops = default_qdisc_ops;
1092
1093 if (dev->priv_flags & IFF_NO_QUEUE)
1094 ops = &noqueue_qdisc_ops;
1095 else if(dev->type == ARPHRD_CAN)
1096 ops = &pfifo_fast_ops;
1097
1098 qdisc = qdisc_create_dflt(dev_queue, ops, TC_H_ROOT, NULL);
1099 if (!qdisc)
1100 return;
1101
1102 if (!netif_is_multiqueue(dev))
1103 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
1104 dev_queue->qdisc_sleeping = qdisc;
1105}
1106
1107static void attach_default_qdiscs(struct net_device *dev)
1108{
1109 struct netdev_queue *txq;
1110 struct Qdisc *qdisc;
1111
1112 txq = netdev_get_tx_queue(dev, 0);
1113
1114 if (!netif_is_multiqueue(dev) ||
1115 dev->priv_flags & IFF_NO_QUEUE) {
1116 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
1117 dev->qdisc = txq->qdisc_sleeping;
1118 qdisc_refcount_inc(dev->qdisc);
1119 } else {
1120 qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT, NULL);
1121 if (qdisc) {
1122 dev->qdisc = qdisc;
1123 qdisc->ops->attach(qdisc);
1124 }
1125 }
1126
1127 /* Detect default qdisc setup/init failed and fallback to "noqueue" */
1128 if (dev->qdisc == &noop_qdisc) {
1129 netdev_warn(dev, "default qdisc (%s) fail, fallback to %s\n",
1130 default_qdisc_ops->id, noqueue_qdisc_ops.id);
1131 dev->priv_flags |= IFF_NO_QUEUE;
1132 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
1133 dev->qdisc = txq->qdisc_sleeping;
1134 qdisc_refcount_inc(dev->qdisc);
1135 dev->priv_flags ^= IFF_NO_QUEUE;
1136 }
1137
1138#ifdef CONFIG_NET_SCHED
1139 if (dev->qdisc != &noop_qdisc)
1140 qdisc_hash_add(dev->qdisc, false);
1141#endif
1142}
1143
1144static void transition_one_qdisc(struct net_device *dev,
1145 struct netdev_queue *dev_queue,
1146 void *_need_watchdog)
1147{
1148 struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
1149 int *need_watchdog_p = _need_watchdog;
1150
1151 if (!(new_qdisc->flags & TCQ_F_BUILTIN))
1152 clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
1153
1154 rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
1155 if (need_watchdog_p) {
1156 dev_queue->trans_start = 0;
1157 *need_watchdog_p = 1;
1158 }
1159}
1160
1161void dev_activate(struct net_device *dev)
1162{
1163 int need_watchdog;
1164
1165 /* No queueing discipline is attached to device;
1166 * create default one for devices, which need queueing
1167 * and noqueue_qdisc for virtual interfaces
1168 */
1169
1170 if (dev->qdisc == &noop_qdisc)
1171 attach_default_qdiscs(dev);
1172
1173 if (!netif_carrier_ok(dev))
1174 /* Delay activation until next carrier-on event */
1175 return;
1176
1177 need_watchdog = 0;
1178 netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
1179 if (dev_ingress_queue(dev))
1180 transition_one_qdisc(dev, dev_ingress_queue(dev), NULL);
1181
1182 if (need_watchdog) {
1183 netif_trans_update(dev);
1184 dev_watchdog_up(dev);
1185 }
1186}
1187EXPORT_SYMBOL(dev_activate);
1188
1189static void qdisc_deactivate(struct Qdisc *qdisc)
1190{
1191 if (qdisc->flags & TCQ_F_BUILTIN)
1192 return;
1193
1194 set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
1195}
1196
1197static void dev_deactivate_queue(struct net_device *dev,
1198 struct netdev_queue *dev_queue,
1199 void *_qdisc_default)
1200{
1201 struct Qdisc *qdisc_default = _qdisc_default;
1202 struct Qdisc *qdisc;
1203
1204 qdisc = rtnl_dereference(dev_queue->qdisc);
1205 if (qdisc) {
1206 qdisc_deactivate(qdisc);
1207 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1208 }
1209}
1210
1211static void dev_reset_queue(struct net_device *dev,
1212 struct netdev_queue *dev_queue,
1213 void *_unused)
1214{
1215 struct Qdisc *qdisc;
1216 bool nolock;
1217
1218 qdisc = dev_queue->qdisc_sleeping;
1219 if (!qdisc)
1220 return;
1221
1222 nolock = qdisc->flags & TCQ_F_NOLOCK;
1223
1224 if (nolock)
1225 spin_lock_bh(&qdisc->seqlock);
1226 spin_lock_bh(qdisc_lock(qdisc));
1227
1228 qdisc_reset(qdisc);
1229
1230 spin_unlock_bh(qdisc_lock(qdisc));
1231 if (nolock) {
1232 clear_bit(__QDISC_STATE_MISSED, &qdisc->state);
1233 clear_bit(__QDISC_STATE_DRAINING, &qdisc->state);
1234 spin_unlock_bh(&qdisc->seqlock);
1235 }
1236}
1237
1238static bool some_qdisc_is_busy(struct net_device *dev)
1239{
1240 unsigned int i;
1241
1242 for (i = 0; i < dev->num_tx_queues; i++) {
1243 struct netdev_queue *dev_queue;
1244 spinlock_t *root_lock;
1245 struct Qdisc *q;
1246 int val;
1247
1248 dev_queue = netdev_get_tx_queue(dev, i);
1249 q = dev_queue->qdisc_sleeping;
1250
1251 root_lock = qdisc_lock(q);
1252 spin_lock_bh(root_lock);
1253
1254 val = (qdisc_is_running(q) ||
1255 test_bit(__QDISC_STATE_SCHED, &q->state));
1256
1257 spin_unlock_bh(root_lock);
1258
1259 if (val)
1260 return true;
1261 }
1262 return false;
1263}
1264
1265/**
1266 * dev_deactivate_many - deactivate transmissions on several devices
1267 * @head: list of devices to deactivate
1268 *
1269 * This function returns only when all outstanding transmissions
1270 * have completed, unless all devices are in dismantle phase.
1271 */
1272void dev_deactivate_many(struct list_head *head)
1273{
1274 struct net_device *dev;
1275
1276 list_for_each_entry(dev, head, close_list) {
1277 netdev_for_each_tx_queue(dev, dev_deactivate_queue,
1278 &noop_qdisc);
1279 if (dev_ingress_queue(dev))
1280 dev_deactivate_queue(dev, dev_ingress_queue(dev),
1281 &noop_qdisc);
1282
1283 dev_watchdog_down(dev);
1284 }
1285
1286 /* Wait for outstanding qdisc-less dev_queue_xmit calls or
1287 * outstanding qdisc enqueuing calls.
1288 * This is avoided if all devices are in dismantle phase :
1289 * Caller will call synchronize_net() for us
1290 */
1291 synchronize_net();
1292
1293 list_for_each_entry(dev, head, close_list) {
1294 netdev_for_each_tx_queue(dev, dev_reset_queue, NULL);
1295
1296 if (dev_ingress_queue(dev))
1297 dev_reset_queue(dev, dev_ingress_queue(dev), NULL);
1298 }
1299
1300 /* Wait for outstanding qdisc_run calls. */
1301 list_for_each_entry(dev, head, close_list) {
1302 while (some_qdisc_is_busy(dev)) {
1303 /* wait_event() would avoid this sleep-loop but would
1304 * require expensive checks in the fast paths of packet
1305 * processing which isn't worth it.
1306 */
1307 schedule_timeout_uninterruptible(1);
1308 }
1309 }
1310}
1311
1312void dev_deactivate(struct net_device *dev)
1313{
1314 LIST_HEAD(single);
1315
1316 list_add(&dev->close_list, &single);
1317 dev_deactivate_many(&single);
1318 list_del(&single);
1319}
1320EXPORT_SYMBOL(dev_deactivate);
1321
1322static int qdisc_change_tx_queue_len(struct net_device *dev,
1323 struct netdev_queue *dev_queue)
1324{
1325 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1326 const struct Qdisc_ops *ops = qdisc->ops;
1327
1328 if (ops->change_tx_queue_len)
1329 return ops->change_tx_queue_len(qdisc, dev->tx_queue_len);
1330 return 0;
1331}
1332
1333int dev_qdisc_change_tx_queue_len(struct net_device *dev)
1334{
1335 bool up = dev->flags & IFF_UP;
1336 unsigned int i;
1337 int ret = 0;
1338
1339 if (up)
1340 dev_deactivate(dev);
1341
1342 for (i = 0; i < dev->num_tx_queues; i++) {
1343 ret = qdisc_change_tx_queue_len(dev, &dev->_tx[i]);
1344
1345 /* TODO: revert changes on a partial failure */
1346 if (ret)
1347 break;
1348 }
1349
1350 if (up)
1351 dev_activate(dev);
1352 return ret;
1353}
1354
1355static void dev_init_scheduler_queue(struct net_device *dev,
1356 struct netdev_queue *dev_queue,
1357 void *_qdisc)
1358{
1359 struct Qdisc *qdisc = _qdisc;
1360
1361 rcu_assign_pointer(dev_queue->qdisc, qdisc);
1362 dev_queue->qdisc_sleeping = qdisc;
1363}
1364
1365void dev_init_scheduler(struct net_device *dev)
1366{
1367 dev->qdisc = &noop_qdisc;
1368 netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
1369 if (dev_ingress_queue(dev))
1370 dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1371
1372 timer_setup(&dev->watchdog_timer, dev_watchdog, 0);
1373}
1374
1375static void shutdown_scheduler_queue(struct net_device *dev,
1376 struct netdev_queue *dev_queue,
1377 void *_qdisc_default)
1378{
1379 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1380 struct Qdisc *qdisc_default = _qdisc_default;
1381
1382 if (qdisc) {
1383 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1384 dev_queue->qdisc_sleeping = qdisc_default;
1385
1386 qdisc_put(qdisc);
1387 }
1388}
1389
1390void dev_shutdown(struct net_device *dev)
1391{
1392 netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
1393 if (dev_ingress_queue(dev))
1394 shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1395 qdisc_put(dev->qdisc);
1396 dev->qdisc = &noop_qdisc;
1397
1398 WARN_ON(timer_pending(&dev->watchdog_timer));
1399}
1400
1401/**
1402 * psched_ratecfg_precompute__() - Pre-compute values for reciprocal division
1403 * @rate: Rate to compute reciprocal division values of
1404 * @mult: Multiplier for reciprocal division
1405 * @shift: Shift for reciprocal division
1406 *
1407 * The multiplier and shift for reciprocal division by rate are stored
1408 * in mult and shift.
1409 *
1410 * The deal here is to replace a divide by a reciprocal one
1411 * in fast path (a reciprocal divide is a multiply and a shift)
1412 *
1413 * Normal formula would be :
1414 * time_in_ns = (NSEC_PER_SEC * len) / rate_bps
1415 *
1416 * We compute mult/shift to use instead :
1417 * time_in_ns = (len * mult) >> shift;
1418 *
1419 * We try to get the highest possible mult value for accuracy,
1420 * but have to make sure no overflows will ever happen.
1421 *
1422 * reciprocal_value() is not used here it doesn't handle 64-bit values.
1423 */
1424static void psched_ratecfg_precompute__(u64 rate, u32 *mult, u8 *shift)
1425{
1426 u64 factor = NSEC_PER_SEC;
1427
1428 *mult = 1;
1429 *shift = 0;
1430
1431 if (rate <= 0)
1432 return;
1433
1434 for (;;) {
1435 *mult = div64_u64(factor, rate);
1436 if (*mult & (1U << 31) || factor & (1ULL << 63))
1437 break;
1438 factor <<= 1;
1439 (*shift)++;
1440 }
1441}
1442
1443void psched_ratecfg_precompute(struct psched_ratecfg *r,
1444 const struct tc_ratespec *conf,
1445 u64 rate64)
1446{
1447 memset(r, 0, sizeof(*r));
1448 r->overhead = conf->overhead;
1449 r->rate_bytes_ps = max_t(u64, conf->rate, rate64);
1450 r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK);
1451 psched_ratecfg_precompute__(r->rate_bytes_ps, &r->mult, &r->shift);
1452}
1453EXPORT_SYMBOL(psched_ratecfg_precompute);
1454
1455void psched_ppscfg_precompute(struct psched_pktrate *r, u64 pktrate64)
1456{
1457 r->rate_pkts_ps = pktrate64;
1458 psched_ratecfg_precompute__(r->rate_pkts_ps, &r->mult, &r->shift);
1459}
1460EXPORT_SYMBOL(psched_ppscfg_precompute);
1461
1462static void mini_qdisc_rcu_func(struct rcu_head *head)
1463{
1464}
1465
1466void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp,
1467 struct tcf_proto *tp_head)
1468{
1469 /* Protected with chain0->filter_chain_lock.
1470 * Can't access chain directly because tp_head can be NULL.
1471 */
1472 struct mini_Qdisc *miniq_old =
1473 rcu_dereference_protected(*miniqp->p_miniq, 1);
1474 struct mini_Qdisc *miniq;
1475
1476 if (!tp_head) {
1477 RCU_INIT_POINTER(*miniqp->p_miniq, NULL);
1478 /* Wait for flying RCU callback before it is freed. */
1479 rcu_barrier();
1480 return;
1481 }
1482
1483 miniq = !miniq_old || miniq_old == &miniqp->miniq2 ?
1484 &miniqp->miniq1 : &miniqp->miniq2;
1485
1486 /* We need to make sure that readers won't see the miniq
1487 * we are about to modify. So wait until previous call_rcu callback
1488 * is done.
1489 */
1490 rcu_barrier();
1491 miniq->filter_list = tp_head;
1492 rcu_assign_pointer(*miniqp->p_miniq, miniq);
1493
1494 if (miniq_old)
1495 /* This is counterpart of the rcu barriers above. We need to
1496 * block potential new user of miniq_old until all readers
1497 * are not seeing it.
1498 */
1499 call_rcu(&miniq_old->rcu, mini_qdisc_rcu_func);
1500}
1501EXPORT_SYMBOL(mini_qdisc_pair_swap);
1502
1503void mini_qdisc_pair_block_init(struct mini_Qdisc_pair *miniqp,
1504 struct tcf_block *block)
1505{
1506 miniqp->miniq1.block = block;
1507 miniqp->miniq2.block = block;
1508}
1509EXPORT_SYMBOL(mini_qdisc_pair_block_init);
1510
1511void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc,
1512 struct mini_Qdisc __rcu **p_miniq)
1513{
1514 miniqp->miniq1.cpu_bstats = qdisc->cpu_bstats;
1515 miniqp->miniq1.cpu_qstats = qdisc->cpu_qstats;
1516 miniqp->miniq2.cpu_bstats = qdisc->cpu_bstats;
1517 miniqp->miniq2.cpu_qstats = qdisc->cpu_qstats;
1518 miniqp->p_miniq = p_miniq;
1519}
1520EXPORT_SYMBOL(mini_qdisc_pair_init);