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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 <net/pkt_sched.h>
29#include <net/dst.h>
30
31/* Main transmission queue. */
32
33/* Modifications to data participating in scheduling must be protected with
34 * qdisc_lock(qdisc) spinlock.
35 *
36 * The idea is the following:
37 * - enqueue, dequeue are serialized via qdisc root lock
38 * - ingress filtering is also serialized via qdisc root lock
39 * - updates to tree and tree walking are only done under the rtnl mutex.
40 */
41
42static inline int dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
43{
44 skb_dst_force(skb);
45 q->gso_skb = skb;
46 q->qstats.requeues++;
47 q->q.qlen++; /* it's still part of the queue */
48 __netif_schedule(q);
49
50 return 0;
51}
52
53static inline struct sk_buff *dequeue_skb(struct Qdisc *q)
54{
55 struct sk_buff *skb = q->gso_skb;
56
57 if (unlikely(skb)) {
58 struct net_device *dev = qdisc_dev(q);
59 struct netdev_queue *txq;
60
61 /* check the reason of requeuing without tx lock first */
62 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
63 if (!netif_tx_queue_frozen_or_stopped(txq)) {
64 q->gso_skb = NULL;
65 q->q.qlen--;
66 } else
67 skb = NULL;
68 } else {
69 skb = q->dequeue(q);
70 }
71
72 return skb;
73}
74
75static inline int handle_dev_cpu_collision(struct sk_buff *skb,
76 struct netdev_queue *dev_queue,
77 struct Qdisc *q)
78{
79 int ret;
80
81 if (unlikely(dev_queue->xmit_lock_owner == smp_processor_id())) {
82 /*
83 * Same CPU holding the lock. It may be a transient
84 * configuration error, when hard_start_xmit() recurses. We
85 * detect it by checking xmit owner and drop the packet when
86 * deadloop is detected. Return OK to try the next skb.
87 */
88 kfree_skb(skb);
89 if (net_ratelimit())
90 pr_warning("Dead loop on netdevice %s, fix it urgently!\n",
91 dev_queue->dev->name);
92 ret = qdisc_qlen(q);
93 } else {
94 /*
95 * Another cpu is holding lock, requeue & delay xmits for
96 * some time.
97 */
98 __this_cpu_inc(softnet_data.cpu_collision);
99 ret = dev_requeue_skb(skb, q);
100 }
101
102 return ret;
103}
104
105/*
106 * Transmit one skb, and handle the return status as required. Holding the
107 * __QDISC_STATE_RUNNING bit guarantees that only one CPU can execute this
108 * function.
109 *
110 * Returns to the caller:
111 * 0 - queue is empty or throttled.
112 * >0 - queue is not empty.
113 */
114int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
115 struct net_device *dev, struct netdev_queue *txq,
116 spinlock_t *root_lock)
117{
118 int ret = NETDEV_TX_BUSY;
119
120 /* And release qdisc */
121 spin_unlock(root_lock);
122
123 HARD_TX_LOCK(dev, txq, smp_processor_id());
124 if (!netif_tx_queue_frozen_or_stopped(txq))
125 ret = dev_hard_start_xmit(skb, dev, txq);
126
127 HARD_TX_UNLOCK(dev, txq);
128
129 spin_lock(root_lock);
130
131 if (dev_xmit_complete(ret)) {
132 /* Driver sent out skb successfully or skb was consumed */
133 ret = qdisc_qlen(q);
134 } else if (ret == NETDEV_TX_LOCKED) {
135 /* Driver try lock failed */
136 ret = handle_dev_cpu_collision(skb, txq, q);
137 } else {
138 /* Driver returned NETDEV_TX_BUSY - requeue skb */
139 if (unlikely (ret != NETDEV_TX_BUSY && net_ratelimit()))
140 pr_warning("BUG %s code %d qlen %d\n",
141 dev->name, ret, q->q.qlen);
142
143 ret = dev_requeue_skb(skb, q);
144 }
145
146 if (ret && netif_tx_queue_frozen_or_stopped(txq))
147 ret = 0;
148
149 return ret;
150}
151
152/*
153 * NOTE: Called under qdisc_lock(q) with locally disabled BH.
154 *
155 * __QDISC_STATE_RUNNING guarantees only one CPU can process
156 * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
157 * this queue.
158 *
159 * netif_tx_lock serializes accesses to device driver.
160 *
161 * qdisc_lock(q) and netif_tx_lock are mutually exclusive,
162 * if one is grabbed, another must be free.
163 *
164 * Note, that this procedure can be called by a watchdog timer
165 *
166 * Returns to the caller:
167 * 0 - queue is empty or throttled.
168 * >0 - queue is not empty.
169 *
170 */
171static inline int qdisc_restart(struct Qdisc *q)
172{
173 struct netdev_queue *txq;
174 struct net_device *dev;
175 spinlock_t *root_lock;
176 struct sk_buff *skb;
177
178 /* Dequeue packet */
179 skb = dequeue_skb(q);
180 if (unlikely(!skb))
181 return 0;
182 WARN_ON_ONCE(skb_dst_is_noref(skb));
183 root_lock = qdisc_lock(q);
184 dev = qdisc_dev(q);
185 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
186
187 return sch_direct_xmit(skb, q, dev, txq, root_lock);
188}
189
190void __qdisc_run(struct Qdisc *q)
191{
192 int quota = weight_p;
193
194 while (qdisc_restart(q)) {
195 /*
196 * Ordered by possible occurrence: Postpone processing if
197 * 1. we've exceeded packet quota
198 * 2. another process needs the CPU;
199 */
200 if (--quota <= 0 || need_resched()) {
201 __netif_schedule(q);
202 break;
203 }
204 }
205
206 qdisc_run_end(q);
207}
208
209unsigned long dev_trans_start(struct net_device *dev)
210{
211 unsigned long val, res = dev->trans_start;
212 unsigned int i;
213
214 for (i = 0; i < dev->num_tx_queues; i++) {
215 val = netdev_get_tx_queue(dev, i)->trans_start;
216 if (val && time_after(val, res))
217 res = val;
218 }
219 dev->trans_start = res;
220 return res;
221}
222EXPORT_SYMBOL(dev_trans_start);
223
224static void dev_watchdog(unsigned long arg)
225{
226 struct net_device *dev = (struct net_device *)arg;
227
228 netif_tx_lock(dev);
229 if (!qdisc_tx_is_noop(dev)) {
230 if (netif_device_present(dev) &&
231 netif_running(dev) &&
232 netif_carrier_ok(dev)) {
233 int some_queue_timedout = 0;
234 unsigned int i;
235 unsigned long trans_start;
236
237 for (i = 0; i < dev->num_tx_queues; i++) {
238 struct netdev_queue *txq;
239
240 txq = netdev_get_tx_queue(dev, i);
241 /*
242 * old device drivers set dev->trans_start
243 */
244 trans_start = txq->trans_start ? : dev->trans_start;
245 if (netif_tx_queue_stopped(txq) &&
246 time_after(jiffies, (trans_start +
247 dev->watchdog_timeo))) {
248 some_queue_timedout = 1;
249 break;
250 }
251 }
252
253 if (some_queue_timedout) {
254 WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",
255 dev->name, netdev_drivername(dev), i);
256 dev->netdev_ops->ndo_tx_timeout(dev);
257 }
258 if (!mod_timer(&dev->watchdog_timer,
259 round_jiffies(jiffies +
260 dev->watchdog_timeo)))
261 dev_hold(dev);
262 }
263 }
264 netif_tx_unlock(dev);
265
266 dev_put(dev);
267}
268
269void __netdev_watchdog_up(struct net_device *dev)
270{
271 if (dev->netdev_ops->ndo_tx_timeout) {
272 if (dev->watchdog_timeo <= 0)
273 dev->watchdog_timeo = 5*HZ;
274 if (!mod_timer(&dev->watchdog_timer,
275 round_jiffies(jiffies + dev->watchdog_timeo)))
276 dev_hold(dev);
277 }
278}
279
280static void dev_watchdog_up(struct net_device *dev)
281{
282 __netdev_watchdog_up(dev);
283}
284
285static void dev_watchdog_down(struct net_device *dev)
286{
287 netif_tx_lock_bh(dev);
288 if (del_timer(&dev->watchdog_timer))
289 dev_put(dev);
290 netif_tx_unlock_bh(dev);
291}
292
293/**
294 * netif_carrier_on - set carrier
295 * @dev: network device
296 *
297 * Device has detected that carrier.
298 */
299void netif_carrier_on(struct net_device *dev)
300{
301 if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
302 if (dev->reg_state == NETREG_UNINITIALIZED)
303 return;
304 linkwatch_fire_event(dev);
305 if (netif_running(dev))
306 __netdev_watchdog_up(dev);
307 }
308}
309EXPORT_SYMBOL(netif_carrier_on);
310
311/**
312 * netif_carrier_off - clear carrier
313 * @dev: network device
314 *
315 * Device has detected loss of carrier.
316 */
317void netif_carrier_off(struct net_device *dev)
318{
319 if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
320 if (dev->reg_state == NETREG_UNINITIALIZED)
321 return;
322 linkwatch_fire_event(dev);
323 }
324}
325EXPORT_SYMBOL(netif_carrier_off);
326
327/**
328 * netif_notify_peers - notify network peers about existence of @dev
329 * @dev: network device
330 *
331 * Generate traffic such that interested network peers are aware of
332 * @dev, such as by generating a gratuitous ARP. This may be used when
333 * a device wants to inform the rest of the network about some sort of
334 * reconfiguration such as a failover event or virtual machine
335 * migration.
336 */
337void netif_notify_peers(struct net_device *dev)
338{
339 rtnl_lock();
340 call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, dev);
341 rtnl_unlock();
342}
343EXPORT_SYMBOL(netif_notify_peers);
344
345/* "NOOP" scheduler: the best scheduler, recommended for all interfaces
346 under all circumstances. It is difficult to invent anything faster or
347 cheaper.
348 */
349
350static int noop_enqueue(struct sk_buff *skb, struct Qdisc * qdisc)
351{
352 kfree_skb(skb);
353 return NET_XMIT_CN;
354}
355
356static struct sk_buff *noop_dequeue(struct Qdisc * qdisc)
357{
358 return NULL;
359}
360
361struct Qdisc_ops noop_qdisc_ops __read_mostly = {
362 .id = "noop",
363 .priv_size = 0,
364 .enqueue = noop_enqueue,
365 .dequeue = noop_dequeue,
366 .peek = noop_dequeue,
367 .owner = THIS_MODULE,
368};
369
370static struct netdev_queue noop_netdev_queue = {
371 .qdisc = &noop_qdisc,
372 .qdisc_sleeping = &noop_qdisc,
373};
374
375struct Qdisc noop_qdisc = {
376 .enqueue = noop_enqueue,
377 .dequeue = noop_dequeue,
378 .flags = TCQ_F_BUILTIN,
379 .ops = &noop_qdisc_ops,
380 .list = LIST_HEAD_INIT(noop_qdisc.list),
381 .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
382 .dev_queue = &noop_netdev_queue,
383 .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
384};
385EXPORT_SYMBOL(noop_qdisc);
386
387static struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
388 .id = "noqueue",
389 .priv_size = 0,
390 .enqueue = noop_enqueue,
391 .dequeue = noop_dequeue,
392 .peek = noop_dequeue,
393 .owner = THIS_MODULE,
394};
395
396static struct Qdisc noqueue_qdisc;
397static struct netdev_queue noqueue_netdev_queue = {
398 .qdisc = &noqueue_qdisc,
399 .qdisc_sleeping = &noqueue_qdisc,
400};
401
402static struct Qdisc noqueue_qdisc = {
403 .enqueue = NULL,
404 .dequeue = noop_dequeue,
405 .flags = TCQ_F_BUILTIN,
406 .ops = &noqueue_qdisc_ops,
407 .list = LIST_HEAD_INIT(noqueue_qdisc.list),
408 .q.lock = __SPIN_LOCK_UNLOCKED(noqueue_qdisc.q.lock),
409 .dev_queue = &noqueue_netdev_queue,
410 .busylock = __SPIN_LOCK_UNLOCKED(noqueue_qdisc.busylock),
411};
412
413
414static const u8 prio2band[TC_PRIO_MAX + 1] = {
415 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1
416};
417
418/* 3-band FIFO queue: old style, but should be a bit faster than
419 generic prio+fifo combination.
420 */
421
422#define PFIFO_FAST_BANDS 3
423
424/*
425 * Private data for a pfifo_fast scheduler containing:
426 * - queues for the three band
427 * - bitmap indicating which of the bands contain skbs
428 */
429struct pfifo_fast_priv {
430 u32 bitmap;
431 struct sk_buff_head q[PFIFO_FAST_BANDS];
432};
433
434/*
435 * Convert a bitmap to the first band number where an skb is queued, where:
436 * bitmap=0 means there are no skbs on any band.
437 * bitmap=1 means there is an skb on band 0.
438 * bitmap=7 means there are skbs on all 3 bands, etc.
439 */
440static const int bitmap2band[] = {-1, 0, 1, 0, 2, 0, 1, 0};
441
442static inline struct sk_buff_head *band2list(struct pfifo_fast_priv *priv,
443 int band)
444{
445 return priv->q + band;
446}
447
448static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc)
449{
450 if (skb_queue_len(&qdisc->q) < qdisc_dev(qdisc)->tx_queue_len) {
451 int band = prio2band[skb->priority & TC_PRIO_MAX];
452 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
453 struct sk_buff_head *list = band2list(priv, band);
454
455 priv->bitmap |= (1 << band);
456 qdisc->q.qlen++;
457 return __qdisc_enqueue_tail(skb, qdisc, list);
458 }
459
460 return qdisc_drop(skb, qdisc);
461}
462
463static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
464{
465 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
466 int band = bitmap2band[priv->bitmap];
467
468 if (likely(band >= 0)) {
469 struct sk_buff_head *list = band2list(priv, band);
470 struct sk_buff *skb = __qdisc_dequeue_head(qdisc, list);
471
472 qdisc->q.qlen--;
473 if (skb_queue_empty(list))
474 priv->bitmap &= ~(1 << band);
475
476 return skb;
477 }
478
479 return NULL;
480}
481
482static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
483{
484 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
485 int band = bitmap2band[priv->bitmap];
486
487 if (band >= 0) {
488 struct sk_buff_head *list = band2list(priv, band);
489
490 return skb_peek(list);
491 }
492
493 return NULL;
494}
495
496static void pfifo_fast_reset(struct Qdisc *qdisc)
497{
498 int prio;
499 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
500
501 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
502 __qdisc_reset_queue(qdisc, band2list(priv, prio));
503
504 priv->bitmap = 0;
505 qdisc->qstats.backlog = 0;
506 qdisc->q.qlen = 0;
507}
508
509static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
510{
511 struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
512
513 memcpy(&opt.priomap, prio2band, TC_PRIO_MAX + 1);
514 NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
515 return skb->len;
516
517nla_put_failure:
518 return -1;
519}
520
521static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt)
522{
523 int prio;
524 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
525
526 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
527 skb_queue_head_init(band2list(priv, prio));
528
529 /* Can by-pass the queue discipline */
530 qdisc->flags |= TCQ_F_CAN_BYPASS;
531 return 0;
532}
533
534struct Qdisc_ops pfifo_fast_ops __read_mostly = {
535 .id = "pfifo_fast",
536 .priv_size = sizeof(struct pfifo_fast_priv),
537 .enqueue = pfifo_fast_enqueue,
538 .dequeue = pfifo_fast_dequeue,
539 .peek = pfifo_fast_peek,
540 .init = pfifo_fast_init,
541 .reset = pfifo_fast_reset,
542 .dump = pfifo_fast_dump,
543 .owner = THIS_MODULE,
544};
545EXPORT_SYMBOL(pfifo_fast_ops);
546
547struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
548 struct Qdisc_ops *ops)
549{
550 void *p;
551 struct Qdisc *sch;
552 unsigned int size = QDISC_ALIGN(sizeof(*sch)) + ops->priv_size;
553 int err = -ENOBUFS;
554
555 p = kzalloc_node(size, GFP_KERNEL,
556 netdev_queue_numa_node_read(dev_queue));
557
558 if (!p)
559 goto errout;
560 sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
561 /* if we got non aligned memory, ask more and do alignment ourself */
562 if (sch != p) {
563 kfree(p);
564 p = kzalloc_node(size + QDISC_ALIGNTO - 1, GFP_KERNEL,
565 netdev_queue_numa_node_read(dev_queue));
566 if (!p)
567 goto errout;
568 sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
569 sch->padded = (char *) sch - (char *) p;
570 }
571 INIT_LIST_HEAD(&sch->list);
572 skb_queue_head_init(&sch->q);
573 spin_lock_init(&sch->busylock);
574 sch->ops = ops;
575 sch->enqueue = ops->enqueue;
576 sch->dequeue = ops->dequeue;
577 sch->dev_queue = dev_queue;
578 dev_hold(qdisc_dev(sch));
579 atomic_set(&sch->refcnt, 1);
580
581 return sch;
582errout:
583 return ERR_PTR(err);
584}
585
586struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
587 struct Qdisc_ops *ops, unsigned int parentid)
588{
589 struct Qdisc *sch;
590
591 sch = qdisc_alloc(dev_queue, ops);
592 if (IS_ERR(sch))
593 goto errout;
594 sch->parent = parentid;
595
596 if (!ops->init || ops->init(sch, NULL) == 0)
597 return sch;
598
599 qdisc_destroy(sch);
600errout:
601 return NULL;
602}
603EXPORT_SYMBOL(qdisc_create_dflt);
604
605/* Under qdisc_lock(qdisc) and BH! */
606
607void qdisc_reset(struct Qdisc *qdisc)
608{
609 const struct Qdisc_ops *ops = qdisc->ops;
610
611 if (ops->reset)
612 ops->reset(qdisc);
613
614 if (qdisc->gso_skb) {
615 kfree_skb(qdisc->gso_skb);
616 qdisc->gso_skb = NULL;
617 qdisc->q.qlen = 0;
618 }
619}
620EXPORT_SYMBOL(qdisc_reset);
621
622static void qdisc_rcu_free(struct rcu_head *head)
623{
624 struct Qdisc *qdisc = container_of(head, struct Qdisc, rcu_head);
625
626 kfree((char *) qdisc - qdisc->padded);
627}
628
629void qdisc_destroy(struct Qdisc *qdisc)
630{
631 const struct Qdisc_ops *ops = qdisc->ops;
632
633 if (qdisc->flags & TCQ_F_BUILTIN ||
634 !atomic_dec_and_test(&qdisc->refcnt))
635 return;
636
637#ifdef CONFIG_NET_SCHED
638 qdisc_list_del(qdisc);
639
640 qdisc_put_stab(rtnl_dereference(qdisc->stab));
641#endif
642 gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est);
643 if (ops->reset)
644 ops->reset(qdisc);
645 if (ops->destroy)
646 ops->destroy(qdisc);
647
648 module_put(ops->owner);
649 dev_put(qdisc_dev(qdisc));
650
651 kfree_skb(qdisc->gso_skb);
652 /*
653 * gen_estimator est_timer() might access qdisc->q.lock,
654 * wait a RCU grace period before freeing qdisc.
655 */
656 call_rcu(&qdisc->rcu_head, qdisc_rcu_free);
657}
658EXPORT_SYMBOL(qdisc_destroy);
659
660/* Attach toplevel qdisc to device queue. */
661struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
662 struct Qdisc *qdisc)
663{
664 struct Qdisc *oqdisc = dev_queue->qdisc_sleeping;
665 spinlock_t *root_lock;
666
667 root_lock = qdisc_lock(oqdisc);
668 spin_lock_bh(root_lock);
669
670 /* Prune old scheduler */
671 if (oqdisc && atomic_read(&oqdisc->refcnt) <= 1)
672 qdisc_reset(oqdisc);
673
674 /* ... and graft new one */
675 if (qdisc == NULL)
676 qdisc = &noop_qdisc;
677 dev_queue->qdisc_sleeping = qdisc;
678 rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
679
680 spin_unlock_bh(root_lock);
681
682 return oqdisc;
683}
684EXPORT_SYMBOL(dev_graft_qdisc);
685
686static void attach_one_default_qdisc(struct net_device *dev,
687 struct netdev_queue *dev_queue,
688 void *_unused)
689{
690 struct Qdisc *qdisc = &noqueue_qdisc;
691
692 if (dev->tx_queue_len) {
693 qdisc = qdisc_create_dflt(dev_queue,
694 &pfifo_fast_ops, TC_H_ROOT);
695 if (!qdisc) {
696 netdev_info(dev, "activation failed\n");
697 return;
698 }
699 }
700 dev_queue->qdisc_sleeping = qdisc;
701}
702
703static void attach_default_qdiscs(struct net_device *dev)
704{
705 struct netdev_queue *txq;
706 struct Qdisc *qdisc;
707
708 txq = netdev_get_tx_queue(dev, 0);
709
710 if (!netif_is_multiqueue(dev) || dev->tx_queue_len == 0) {
711 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
712 dev->qdisc = txq->qdisc_sleeping;
713 atomic_inc(&dev->qdisc->refcnt);
714 } else {
715 qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT);
716 if (qdisc) {
717 qdisc->ops->attach(qdisc);
718 dev->qdisc = qdisc;
719 }
720 }
721}
722
723static void transition_one_qdisc(struct net_device *dev,
724 struct netdev_queue *dev_queue,
725 void *_need_watchdog)
726{
727 struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
728 int *need_watchdog_p = _need_watchdog;
729
730 if (!(new_qdisc->flags & TCQ_F_BUILTIN))
731 clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
732
733 rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
734 if (need_watchdog_p && new_qdisc != &noqueue_qdisc) {
735 dev_queue->trans_start = 0;
736 *need_watchdog_p = 1;
737 }
738}
739
740void dev_activate(struct net_device *dev)
741{
742 int need_watchdog;
743
744 /* No queueing discipline is attached to device;
745 create default one i.e. pfifo_fast for devices,
746 which need queueing and noqueue_qdisc for
747 virtual interfaces
748 */
749
750 if (dev->qdisc == &noop_qdisc)
751 attach_default_qdiscs(dev);
752
753 if (!netif_carrier_ok(dev))
754 /* Delay activation until next carrier-on event */
755 return;
756
757 need_watchdog = 0;
758 netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
759 if (dev_ingress_queue(dev))
760 transition_one_qdisc(dev, dev_ingress_queue(dev), NULL);
761
762 if (need_watchdog) {
763 dev->trans_start = jiffies;
764 dev_watchdog_up(dev);
765 }
766}
767EXPORT_SYMBOL(dev_activate);
768
769static void dev_deactivate_queue(struct net_device *dev,
770 struct netdev_queue *dev_queue,
771 void *_qdisc_default)
772{
773 struct Qdisc *qdisc_default = _qdisc_default;
774 struct Qdisc *qdisc;
775
776 qdisc = dev_queue->qdisc;
777 if (qdisc) {
778 spin_lock_bh(qdisc_lock(qdisc));
779
780 if (!(qdisc->flags & TCQ_F_BUILTIN))
781 set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
782
783 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
784 qdisc_reset(qdisc);
785
786 spin_unlock_bh(qdisc_lock(qdisc));
787 }
788}
789
790static bool some_qdisc_is_busy(struct net_device *dev)
791{
792 unsigned int i;
793
794 for (i = 0; i < dev->num_tx_queues; i++) {
795 struct netdev_queue *dev_queue;
796 spinlock_t *root_lock;
797 struct Qdisc *q;
798 int val;
799
800 dev_queue = netdev_get_tx_queue(dev, i);
801 q = dev_queue->qdisc_sleeping;
802 root_lock = qdisc_lock(q);
803
804 spin_lock_bh(root_lock);
805
806 val = (qdisc_is_running(q) ||
807 test_bit(__QDISC_STATE_SCHED, &q->state));
808
809 spin_unlock_bh(root_lock);
810
811 if (val)
812 return true;
813 }
814 return false;
815}
816
817/**
818 * dev_deactivate_many - deactivate transmissions on several devices
819 * @head: list of devices to deactivate
820 *
821 * This function returns only when all outstanding transmissions
822 * have completed, unless all devices are in dismantle phase.
823 */
824void dev_deactivate_many(struct list_head *head)
825{
826 struct net_device *dev;
827 bool sync_needed = false;
828
829 list_for_each_entry(dev, head, unreg_list) {
830 netdev_for_each_tx_queue(dev, dev_deactivate_queue,
831 &noop_qdisc);
832 if (dev_ingress_queue(dev))
833 dev_deactivate_queue(dev, dev_ingress_queue(dev),
834 &noop_qdisc);
835
836 dev_watchdog_down(dev);
837 sync_needed |= !dev->dismantle;
838 }
839
840 /* Wait for outstanding qdisc-less dev_queue_xmit calls.
841 * This is avoided if all devices are in dismantle phase :
842 * Caller will call synchronize_net() for us
843 */
844 if (sync_needed)
845 synchronize_net();
846
847 /* Wait for outstanding qdisc_run calls. */
848 list_for_each_entry(dev, head, unreg_list)
849 while (some_qdisc_is_busy(dev))
850 yield();
851}
852
853void dev_deactivate(struct net_device *dev)
854{
855 LIST_HEAD(single);
856
857 list_add(&dev->unreg_list, &single);
858 dev_deactivate_many(&single);
859 list_del(&single);
860}
861EXPORT_SYMBOL(dev_deactivate);
862
863static void dev_init_scheduler_queue(struct net_device *dev,
864 struct netdev_queue *dev_queue,
865 void *_qdisc)
866{
867 struct Qdisc *qdisc = _qdisc;
868
869 dev_queue->qdisc = qdisc;
870 dev_queue->qdisc_sleeping = qdisc;
871}
872
873void dev_init_scheduler(struct net_device *dev)
874{
875 dev->qdisc = &noop_qdisc;
876 netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
877 if (dev_ingress_queue(dev))
878 dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
879
880 setup_timer(&dev->watchdog_timer, dev_watchdog, (unsigned long)dev);
881}
882
883static void shutdown_scheduler_queue(struct net_device *dev,
884 struct netdev_queue *dev_queue,
885 void *_qdisc_default)
886{
887 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
888 struct Qdisc *qdisc_default = _qdisc_default;
889
890 if (qdisc) {
891 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
892 dev_queue->qdisc_sleeping = qdisc_default;
893
894 qdisc_destroy(qdisc);
895 }
896}
897
898void dev_shutdown(struct net_device *dev)
899{
900 netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
901 if (dev_ingress_queue(dev))
902 shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
903 qdisc_destroy(dev->qdisc);
904 dev->qdisc = &noop_qdisc;
905
906 WARN_ON(timer_pending(&dev->watchdog_timer));
907}
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 qdisc running bit guarantees that only one CPU
308 * 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 = READ_ONCE(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 res = READ_ONCE(netdev_get_tx_queue(dev, 0)->trans_start);
431 unsigned long val;
432 unsigned int i;
433
434 for (i = 1; i < dev->num_tx_queues; i++) {
435 val = READ_ONCE(netdev_get_tx_queue(dev, i)->trans_start);
436 if (val && time_after(val, res))
437 res = val;
438 }
439
440 return res;
441}
442EXPORT_SYMBOL(dev_trans_start);
443
444static void netif_freeze_queues(struct net_device *dev)
445{
446 unsigned int i;
447 int cpu;
448
449 cpu = smp_processor_id();
450 for (i = 0; i < dev->num_tx_queues; i++) {
451 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
452
453 /* We are the only thread of execution doing a
454 * freeze, but we have to grab the _xmit_lock in
455 * order to synchronize with threads which are in
456 * the ->hard_start_xmit() handler and already
457 * checked the frozen bit.
458 */
459 __netif_tx_lock(txq, cpu);
460 set_bit(__QUEUE_STATE_FROZEN, &txq->state);
461 __netif_tx_unlock(txq);
462 }
463}
464
465void netif_tx_lock(struct net_device *dev)
466{
467 spin_lock(&dev->tx_global_lock);
468 netif_freeze_queues(dev);
469}
470EXPORT_SYMBOL(netif_tx_lock);
471
472static void netif_unfreeze_queues(struct net_device *dev)
473{
474 unsigned int i;
475
476 for (i = 0; i < dev->num_tx_queues; i++) {
477 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
478
479 /* No need to grab the _xmit_lock here. If the
480 * queue is not stopped for another reason, we
481 * force a schedule.
482 */
483 clear_bit(__QUEUE_STATE_FROZEN, &txq->state);
484 netif_schedule_queue(txq);
485 }
486}
487
488void netif_tx_unlock(struct net_device *dev)
489{
490 netif_unfreeze_queues(dev);
491 spin_unlock(&dev->tx_global_lock);
492}
493EXPORT_SYMBOL(netif_tx_unlock);
494
495static void dev_watchdog(struct timer_list *t)
496{
497 struct net_device *dev = from_timer(dev, t, watchdog_timer);
498 bool release = true;
499
500 spin_lock(&dev->tx_global_lock);
501 if (!qdisc_tx_is_noop(dev)) {
502 if (netif_device_present(dev) &&
503 netif_running(dev) &&
504 netif_carrier_ok(dev)) {
505 int some_queue_timedout = 0;
506 unsigned int i;
507 unsigned long trans_start;
508
509 for (i = 0; i < dev->num_tx_queues; i++) {
510 struct netdev_queue *txq;
511
512 txq = netdev_get_tx_queue(dev, i);
513 trans_start = READ_ONCE(txq->trans_start);
514 if (netif_xmit_stopped(txq) &&
515 time_after(jiffies, (trans_start +
516 dev->watchdog_timeo))) {
517 some_queue_timedout = 1;
518 atomic_long_inc(&txq->trans_timeout);
519 break;
520 }
521 }
522
523 if (unlikely(some_queue_timedout)) {
524 trace_net_dev_xmit_timeout(dev, i);
525 WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",
526 dev->name, netdev_drivername(dev), i);
527 netif_freeze_queues(dev);
528 dev->netdev_ops->ndo_tx_timeout(dev, i);
529 netif_unfreeze_queues(dev);
530 }
531 if (!mod_timer(&dev->watchdog_timer,
532 round_jiffies(jiffies +
533 dev->watchdog_timeo)))
534 release = false;
535 }
536 }
537 spin_unlock(&dev->tx_global_lock);
538
539 if (release)
540 netdev_put(dev, &dev->watchdog_dev_tracker);
541}
542
543void __netdev_watchdog_up(struct net_device *dev)
544{
545 if (dev->netdev_ops->ndo_tx_timeout) {
546 if (dev->watchdog_timeo <= 0)
547 dev->watchdog_timeo = 5*HZ;
548 if (!mod_timer(&dev->watchdog_timer,
549 round_jiffies(jiffies + dev->watchdog_timeo)))
550 netdev_hold(dev, &dev->watchdog_dev_tracker,
551 GFP_ATOMIC);
552 }
553}
554EXPORT_SYMBOL_GPL(__netdev_watchdog_up);
555
556static void dev_watchdog_up(struct net_device *dev)
557{
558 __netdev_watchdog_up(dev);
559}
560
561static void dev_watchdog_down(struct net_device *dev)
562{
563 netif_tx_lock_bh(dev);
564 if (del_timer(&dev->watchdog_timer))
565 netdev_put(dev, &dev->watchdog_dev_tracker);
566 netif_tx_unlock_bh(dev);
567}
568
569/**
570 * netif_carrier_on - set carrier
571 * @dev: network device
572 *
573 * Device has detected acquisition of carrier.
574 */
575void netif_carrier_on(struct net_device *dev)
576{
577 if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
578 if (dev->reg_state == NETREG_UNINITIALIZED)
579 return;
580 atomic_inc(&dev->carrier_up_count);
581 linkwatch_fire_event(dev);
582 if (netif_running(dev))
583 __netdev_watchdog_up(dev);
584 }
585}
586EXPORT_SYMBOL(netif_carrier_on);
587
588/**
589 * netif_carrier_off - clear carrier
590 * @dev: network device
591 *
592 * Device has detected loss of carrier.
593 */
594void netif_carrier_off(struct net_device *dev)
595{
596 if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
597 if (dev->reg_state == NETREG_UNINITIALIZED)
598 return;
599 atomic_inc(&dev->carrier_down_count);
600 linkwatch_fire_event(dev);
601 }
602}
603EXPORT_SYMBOL(netif_carrier_off);
604
605/**
606 * netif_carrier_event - report carrier state event
607 * @dev: network device
608 *
609 * Device has detected a carrier event but the carrier state wasn't changed.
610 * Use in drivers when querying carrier state asynchronously, to avoid missing
611 * events (link flaps) if link recovers before it's queried.
612 */
613void netif_carrier_event(struct net_device *dev)
614{
615 if (dev->reg_state == NETREG_UNINITIALIZED)
616 return;
617 atomic_inc(&dev->carrier_up_count);
618 atomic_inc(&dev->carrier_down_count);
619 linkwatch_fire_event(dev);
620}
621EXPORT_SYMBOL_GPL(netif_carrier_event);
622
623/* "NOOP" scheduler: the best scheduler, recommended for all interfaces
624 under all circumstances. It is difficult to invent anything faster or
625 cheaper.
626 */
627
628static int noop_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
629 struct sk_buff **to_free)
630{
631 __qdisc_drop(skb, to_free);
632 return NET_XMIT_CN;
633}
634
635static struct sk_buff *noop_dequeue(struct Qdisc *qdisc)
636{
637 return NULL;
638}
639
640struct Qdisc_ops noop_qdisc_ops __read_mostly = {
641 .id = "noop",
642 .priv_size = 0,
643 .enqueue = noop_enqueue,
644 .dequeue = noop_dequeue,
645 .peek = noop_dequeue,
646 .owner = THIS_MODULE,
647};
648
649static struct netdev_queue noop_netdev_queue = {
650 RCU_POINTER_INITIALIZER(qdisc, &noop_qdisc),
651 .qdisc_sleeping = &noop_qdisc,
652};
653
654struct Qdisc noop_qdisc = {
655 .enqueue = noop_enqueue,
656 .dequeue = noop_dequeue,
657 .flags = TCQ_F_BUILTIN,
658 .ops = &noop_qdisc_ops,
659 .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
660 .dev_queue = &noop_netdev_queue,
661 .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
662 .gso_skb = {
663 .next = (struct sk_buff *)&noop_qdisc.gso_skb,
664 .prev = (struct sk_buff *)&noop_qdisc.gso_skb,
665 .qlen = 0,
666 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.gso_skb.lock),
667 },
668 .skb_bad_txq = {
669 .next = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
670 .prev = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
671 .qlen = 0,
672 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.skb_bad_txq.lock),
673 },
674};
675EXPORT_SYMBOL(noop_qdisc);
676
677static int noqueue_init(struct Qdisc *qdisc, struct nlattr *opt,
678 struct netlink_ext_ack *extack)
679{
680 /* register_qdisc() assigns a default of noop_enqueue if unset,
681 * but __dev_queue_xmit() treats noqueue only as such
682 * if this is NULL - so clear it here. */
683 qdisc->enqueue = NULL;
684 return 0;
685}
686
687struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
688 .id = "noqueue",
689 .priv_size = 0,
690 .init = noqueue_init,
691 .enqueue = noop_enqueue,
692 .dequeue = noop_dequeue,
693 .peek = noop_dequeue,
694 .owner = THIS_MODULE,
695};
696
697static const u8 prio2band[TC_PRIO_MAX + 1] = {
698 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1
699};
700
701/* 3-band FIFO queue: old style, but should be a bit faster than
702 generic prio+fifo combination.
703 */
704
705#define PFIFO_FAST_BANDS 3
706
707/*
708 * Private data for a pfifo_fast scheduler containing:
709 * - rings for priority bands
710 */
711struct pfifo_fast_priv {
712 struct skb_array q[PFIFO_FAST_BANDS];
713};
714
715static inline struct skb_array *band2list(struct pfifo_fast_priv *priv,
716 int band)
717{
718 return &priv->q[band];
719}
720
721static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
722 struct sk_buff **to_free)
723{
724 int band = prio2band[skb->priority & TC_PRIO_MAX];
725 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
726 struct skb_array *q = band2list(priv, band);
727 unsigned int pkt_len = qdisc_pkt_len(skb);
728 int err;
729
730 err = skb_array_produce(q, skb);
731
732 if (unlikely(err)) {
733 if (qdisc_is_percpu_stats(qdisc))
734 return qdisc_drop_cpu(skb, qdisc, to_free);
735 else
736 return qdisc_drop(skb, qdisc, to_free);
737 }
738
739 qdisc_update_stats_at_enqueue(qdisc, pkt_len);
740 return NET_XMIT_SUCCESS;
741}
742
743static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
744{
745 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
746 struct sk_buff *skb = NULL;
747 bool need_retry = true;
748 int band;
749
750retry:
751 for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
752 struct skb_array *q = band2list(priv, band);
753
754 if (__skb_array_empty(q))
755 continue;
756
757 skb = __skb_array_consume(q);
758 }
759 if (likely(skb)) {
760 qdisc_update_stats_at_dequeue(qdisc, skb);
761 } else if (need_retry &&
762 READ_ONCE(qdisc->state) & QDISC_STATE_NON_EMPTY) {
763 /* Delay clearing the STATE_MISSED here to reduce
764 * the overhead of the second spin_trylock() in
765 * qdisc_run_begin() and __netif_schedule() calling
766 * in qdisc_run_end().
767 */
768 clear_bit(__QDISC_STATE_MISSED, &qdisc->state);
769 clear_bit(__QDISC_STATE_DRAINING, &qdisc->state);
770
771 /* Make sure dequeuing happens after clearing
772 * STATE_MISSED.
773 */
774 smp_mb__after_atomic();
775
776 need_retry = false;
777
778 goto retry;
779 }
780
781 return skb;
782}
783
784static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
785{
786 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
787 struct sk_buff *skb = NULL;
788 int band;
789
790 for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
791 struct skb_array *q = band2list(priv, band);
792
793 skb = __skb_array_peek(q);
794 }
795
796 return skb;
797}
798
799static void pfifo_fast_reset(struct Qdisc *qdisc)
800{
801 int i, band;
802 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
803
804 for (band = 0; band < PFIFO_FAST_BANDS; band++) {
805 struct skb_array *q = band2list(priv, band);
806 struct sk_buff *skb;
807
808 /* NULL ring is possible if destroy path is due to a failed
809 * skb_array_init() in pfifo_fast_init() case.
810 */
811 if (!q->ring.queue)
812 continue;
813
814 while ((skb = __skb_array_consume(q)) != NULL)
815 kfree_skb(skb);
816 }
817
818 if (qdisc_is_percpu_stats(qdisc)) {
819 for_each_possible_cpu(i) {
820 struct gnet_stats_queue *q;
821
822 q = per_cpu_ptr(qdisc->cpu_qstats, i);
823 q->backlog = 0;
824 q->qlen = 0;
825 }
826 }
827}
828
829static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
830{
831 struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
832
833 memcpy(&opt.priomap, prio2band, TC_PRIO_MAX + 1);
834 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
835 goto nla_put_failure;
836 return skb->len;
837
838nla_put_failure:
839 return -1;
840}
841
842static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt,
843 struct netlink_ext_ack *extack)
844{
845 unsigned int qlen = qdisc_dev(qdisc)->tx_queue_len;
846 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
847 int prio;
848
849 /* guard against zero length rings */
850 if (!qlen)
851 return -EINVAL;
852
853 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
854 struct skb_array *q = band2list(priv, prio);
855 int err;
856
857 err = skb_array_init(q, qlen, GFP_KERNEL);
858 if (err)
859 return -ENOMEM;
860 }
861
862 /* Can by-pass the queue discipline */
863 qdisc->flags |= TCQ_F_CAN_BYPASS;
864 return 0;
865}
866
867static void pfifo_fast_destroy(struct Qdisc *sch)
868{
869 struct pfifo_fast_priv *priv = qdisc_priv(sch);
870 int prio;
871
872 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
873 struct skb_array *q = band2list(priv, prio);
874
875 /* NULL ring is possible if destroy path is due to a failed
876 * skb_array_init() in pfifo_fast_init() case.
877 */
878 if (!q->ring.queue)
879 continue;
880 /* Destroy ring but no need to kfree_skb because a call to
881 * pfifo_fast_reset() has already done that work.
882 */
883 ptr_ring_cleanup(&q->ring, NULL);
884 }
885}
886
887static int pfifo_fast_change_tx_queue_len(struct Qdisc *sch,
888 unsigned int new_len)
889{
890 struct pfifo_fast_priv *priv = qdisc_priv(sch);
891 struct skb_array *bands[PFIFO_FAST_BANDS];
892 int prio;
893
894 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
895 struct skb_array *q = band2list(priv, prio);
896
897 bands[prio] = q;
898 }
899
900 return skb_array_resize_multiple(bands, PFIFO_FAST_BANDS, new_len,
901 GFP_KERNEL);
902}
903
904struct Qdisc_ops pfifo_fast_ops __read_mostly = {
905 .id = "pfifo_fast",
906 .priv_size = sizeof(struct pfifo_fast_priv),
907 .enqueue = pfifo_fast_enqueue,
908 .dequeue = pfifo_fast_dequeue,
909 .peek = pfifo_fast_peek,
910 .init = pfifo_fast_init,
911 .destroy = pfifo_fast_destroy,
912 .reset = pfifo_fast_reset,
913 .dump = pfifo_fast_dump,
914 .change_tx_queue_len = pfifo_fast_change_tx_queue_len,
915 .owner = THIS_MODULE,
916 .static_flags = TCQ_F_NOLOCK | TCQ_F_CPUSTATS,
917};
918EXPORT_SYMBOL(pfifo_fast_ops);
919
920static struct lock_class_key qdisc_tx_busylock;
921
922struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
923 const struct Qdisc_ops *ops,
924 struct netlink_ext_ack *extack)
925{
926 struct Qdisc *sch;
927 unsigned int size = sizeof(*sch) + ops->priv_size;
928 int err = -ENOBUFS;
929 struct net_device *dev;
930
931 if (!dev_queue) {
932 NL_SET_ERR_MSG(extack, "No device queue given");
933 err = -EINVAL;
934 goto errout;
935 }
936
937 dev = dev_queue->dev;
938 sch = kzalloc_node(size, GFP_KERNEL, netdev_queue_numa_node_read(dev_queue));
939
940 if (!sch)
941 goto errout;
942 __skb_queue_head_init(&sch->gso_skb);
943 __skb_queue_head_init(&sch->skb_bad_txq);
944 gnet_stats_basic_sync_init(&sch->bstats);
945 spin_lock_init(&sch->q.lock);
946
947 if (ops->static_flags & TCQ_F_CPUSTATS) {
948 sch->cpu_bstats =
949 netdev_alloc_pcpu_stats(struct gnet_stats_basic_sync);
950 if (!sch->cpu_bstats)
951 goto errout1;
952
953 sch->cpu_qstats = alloc_percpu(struct gnet_stats_queue);
954 if (!sch->cpu_qstats) {
955 free_percpu(sch->cpu_bstats);
956 goto errout1;
957 }
958 }
959
960 spin_lock_init(&sch->busylock);
961 lockdep_set_class(&sch->busylock,
962 dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
963
964 /* seqlock has the same scope of busylock, for NOLOCK qdisc */
965 spin_lock_init(&sch->seqlock);
966 lockdep_set_class(&sch->seqlock,
967 dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
968
969 sch->ops = ops;
970 sch->flags = ops->static_flags;
971 sch->enqueue = ops->enqueue;
972 sch->dequeue = ops->dequeue;
973 sch->dev_queue = dev_queue;
974 netdev_hold(dev, &sch->dev_tracker, GFP_KERNEL);
975 refcount_set(&sch->refcnt, 1);
976
977 return sch;
978errout1:
979 kfree(sch);
980errout:
981 return ERR_PTR(err);
982}
983
984struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
985 const struct Qdisc_ops *ops,
986 unsigned int parentid,
987 struct netlink_ext_ack *extack)
988{
989 struct Qdisc *sch;
990
991 if (!try_module_get(ops->owner)) {
992 NL_SET_ERR_MSG(extack, "Failed to increase module reference counter");
993 return NULL;
994 }
995
996 sch = qdisc_alloc(dev_queue, ops, extack);
997 if (IS_ERR(sch)) {
998 module_put(ops->owner);
999 return NULL;
1000 }
1001 sch->parent = parentid;
1002
1003 if (!ops->init || ops->init(sch, NULL, extack) == 0) {
1004 trace_qdisc_create(ops, dev_queue->dev, parentid);
1005 return sch;
1006 }
1007
1008 qdisc_put(sch);
1009 return NULL;
1010}
1011EXPORT_SYMBOL(qdisc_create_dflt);
1012
1013/* Under qdisc_lock(qdisc) and BH! */
1014
1015void qdisc_reset(struct Qdisc *qdisc)
1016{
1017 const struct Qdisc_ops *ops = qdisc->ops;
1018
1019 trace_qdisc_reset(qdisc);
1020
1021 if (ops->reset)
1022 ops->reset(qdisc);
1023
1024 __skb_queue_purge(&qdisc->gso_skb);
1025 __skb_queue_purge(&qdisc->skb_bad_txq);
1026
1027 qdisc->q.qlen = 0;
1028 qdisc->qstats.backlog = 0;
1029}
1030EXPORT_SYMBOL(qdisc_reset);
1031
1032void qdisc_free(struct Qdisc *qdisc)
1033{
1034 if (qdisc_is_percpu_stats(qdisc)) {
1035 free_percpu(qdisc->cpu_bstats);
1036 free_percpu(qdisc->cpu_qstats);
1037 }
1038
1039 kfree(qdisc);
1040}
1041
1042static void qdisc_free_cb(struct rcu_head *head)
1043{
1044 struct Qdisc *q = container_of(head, struct Qdisc, rcu);
1045
1046 qdisc_free(q);
1047}
1048
1049static void qdisc_destroy(struct Qdisc *qdisc)
1050{
1051 const struct Qdisc_ops *ops = qdisc->ops;
1052
1053#ifdef CONFIG_NET_SCHED
1054 qdisc_hash_del(qdisc);
1055
1056 qdisc_put_stab(rtnl_dereference(qdisc->stab));
1057#endif
1058 gen_kill_estimator(&qdisc->rate_est);
1059
1060 qdisc_reset(qdisc);
1061
1062 if (ops->destroy)
1063 ops->destroy(qdisc);
1064
1065 module_put(ops->owner);
1066 netdev_put(qdisc_dev(qdisc), &qdisc->dev_tracker);
1067
1068 trace_qdisc_destroy(qdisc);
1069
1070 call_rcu(&qdisc->rcu, qdisc_free_cb);
1071}
1072
1073void qdisc_put(struct Qdisc *qdisc)
1074{
1075 if (!qdisc)
1076 return;
1077
1078 if (qdisc->flags & TCQ_F_BUILTIN ||
1079 !refcount_dec_and_test(&qdisc->refcnt))
1080 return;
1081
1082 qdisc_destroy(qdisc);
1083}
1084EXPORT_SYMBOL(qdisc_put);
1085
1086/* Version of qdisc_put() that is called with rtnl mutex unlocked.
1087 * Intended to be used as optimization, this function only takes rtnl lock if
1088 * qdisc reference counter reached zero.
1089 */
1090
1091void qdisc_put_unlocked(struct Qdisc *qdisc)
1092{
1093 if (qdisc->flags & TCQ_F_BUILTIN ||
1094 !refcount_dec_and_rtnl_lock(&qdisc->refcnt))
1095 return;
1096
1097 qdisc_destroy(qdisc);
1098 rtnl_unlock();
1099}
1100EXPORT_SYMBOL(qdisc_put_unlocked);
1101
1102/* Attach toplevel qdisc to device queue. */
1103struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
1104 struct Qdisc *qdisc)
1105{
1106 struct Qdisc *oqdisc = dev_queue->qdisc_sleeping;
1107 spinlock_t *root_lock;
1108
1109 root_lock = qdisc_lock(oqdisc);
1110 spin_lock_bh(root_lock);
1111
1112 /* ... and graft new one */
1113 if (qdisc == NULL)
1114 qdisc = &noop_qdisc;
1115 dev_queue->qdisc_sleeping = qdisc;
1116 rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
1117
1118 spin_unlock_bh(root_lock);
1119
1120 return oqdisc;
1121}
1122EXPORT_SYMBOL(dev_graft_qdisc);
1123
1124static void shutdown_scheduler_queue(struct net_device *dev,
1125 struct netdev_queue *dev_queue,
1126 void *_qdisc_default)
1127{
1128 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1129 struct Qdisc *qdisc_default = _qdisc_default;
1130
1131 if (qdisc) {
1132 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1133 dev_queue->qdisc_sleeping = qdisc_default;
1134
1135 qdisc_put(qdisc);
1136 }
1137}
1138
1139static void attach_one_default_qdisc(struct net_device *dev,
1140 struct netdev_queue *dev_queue,
1141 void *_unused)
1142{
1143 struct Qdisc *qdisc;
1144 const struct Qdisc_ops *ops = default_qdisc_ops;
1145
1146 if (dev->priv_flags & IFF_NO_QUEUE)
1147 ops = &noqueue_qdisc_ops;
1148 else if(dev->type == ARPHRD_CAN)
1149 ops = &pfifo_fast_ops;
1150
1151 qdisc = qdisc_create_dflt(dev_queue, ops, TC_H_ROOT, NULL);
1152 if (!qdisc)
1153 return;
1154
1155 if (!netif_is_multiqueue(dev))
1156 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
1157 dev_queue->qdisc_sleeping = qdisc;
1158}
1159
1160static void attach_default_qdiscs(struct net_device *dev)
1161{
1162 struct netdev_queue *txq;
1163 struct Qdisc *qdisc;
1164
1165 txq = netdev_get_tx_queue(dev, 0);
1166
1167 if (!netif_is_multiqueue(dev) ||
1168 dev->priv_flags & IFF_NO_QUEUE) {
1169 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
1170 qdisc = txq->qdisc_sleeping;
1171 rcu_assign_pointer(dev->qdisc, qdisc);
1172 qdisc_refcount_inc(qdisc);
1173 } else {
1174 qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT, NULL);
1175 if (qdisc) {
1176 rcu_assign_pointer(dev->qdisc, qdisc);
1177 qdisc->ops->attach(qdisc);
1178 }
1179 }
1180 qdisc = rtnl_dereference(dev->qdisc);
1181
1182 /* Detect default qdisc setup/init failed and fallback to "noqueue" */
1183 if (qdisc == &noop_qdisc) {
1184 netdev_warn(dev, "default qdisc (%s) fail, fallback to %s\n",
1185 default_qdisc_ops->id, noqueue_qdisc_ops.id);
1186 netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
1187 dev->priv_flags |= IFF_NO_QUEUE;
1188 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
1189 qdisc = txq->qdisc_sleeping;
1190 rcu_assign_pointer(dev->qdisc, qdisc);
1191 qdisc_refcount_inc(qdisc);
1192 dev->priv_flags ^= IFF_NO_QUEUE;
1193 }
1194
1195#ifdef CONFIG_NET_SCHED
1196 if (qdisc != &noop_qdisc)
1197 qdisc_hash_add(qdisc, false);
1198#endif
1199}
1200
1201static void transition_one_qdisc(struct net_device *dev,
1202 struct netdev_queue *dev_queue,
1203 void *_need_watchdog)
1204{
1205 struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
1206 int *need_watchdog_p = _need_watchdog;
1207
1208 if (!(new_qdisc->flags & TCQ_F_BUILTIN))
1209 clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
1210
1211 rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
1212 if (need_watchdog_p) {
1213 WRITE_ONCE(dev_queue->trans_start, 0);
1214 *need_watchdog_p = 1;
1215 }
1216}
1217
1218void dev_activate(struct net_device *dev)
1219{
1220 int need_watchdog;
1221
1222 /* No queueing discipline is attached to device;
1223 * create default one for devices, which need queueing
1224 * and noqueue_qdisc for virtual interfaces
1225 */
1226
1227 if (rtnl_dereference(dev->qdisc) == &noop_qdisc)
1228 attach_default_qdiscs(dev);
1229
1230 if (!netif_carrier_ok(dev))
1231 /* Delay activation until next carrier-on event */
1232 return;
1233
1234 need_watchdog = 0;
1235 netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
1236 if (dev_ingress_queue(dev))
1237 transition_one_qdisc(dev, dev_ingress_queue(dev), NULL);
1238
1239 if (need_watchdog) {
1240 netif_trans_update(dev);
1241 dev_watchdog_up(dev);
1242 }
1243}
1244EXPORT_SYMBOL(dev_activate);
1245
1246static void qdisc_deactivate(struct Qdisc *qdisc)
1247{
1248 if (qdisc->flags & TCQ_F_BUILTIN)
1249 return;
1250
1251 set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
1252}
1253
1254static void dev_deactivate_queue(struct net_device *dev,
1255 struct netdev_queue *dev_queue,
1256 void *_qdisc_default)
1257{
1258 struct Qdisc *qdisc_default = _qdisc_default;
1259 struct Qdisc *qdisc;
1260
1261 qdisc = rtnl_dereference(dev_queue->qdisc);
1262 if (qdisc) {
1263 qdisc_deactivate(qdisc);
1264 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1265 }
1266}
1267
1268static void dev_reset_queue(struct net_device *dev,
1269 struct netdev_queue *dev_queue,
1270 void *_unused)
1271{
1272 struct Qdisc *qdisc;
1273 bool nolock;
1274
1275 qdisc = dev_queue->qdisc_sleeping;
1276 if (!qdisc)
1277 return;
1278
1279 nolock = qdisc->flags & TCQ_F_NOLOCK;
1280
1281 if (nolock)
1282 spin_lock_bh(&qdisc->seqlock);
1283 spin_lock_bh(qdisc_lock(qdisc));
1284
1285 qdisc_reset(qdisc);
1286
1287 spin_unlock_bh(qdisc_lock(qdisc));
1288 if (nolock) {
1289 clear_bit(__QDISC_STATE_MISSED, &qdisc->state);
1290 clear_bit(__QDISC_STATE_DRAINING, &qdisc->state);
1291 spin_unlock_bh(&qdisc->seqlock);
1292 }
1293}
1294
1295static bool some_qdisc_is_busy(struct net_device *dev)
1296{
1297 unsigned int i;
1298
1299 for (i = 0; i < dev->num_tx_queues; i++) {
1300 struct netdev_queue *dev_queue;
1301 spinlock_t *root_lock;
1302 struct Qdisc *q;
1303 int val;
1304
1305 dev_queue = netdev_get_tx_queue(dev, i);
1306 q = dev_queue->qdisc_sleeping;
1307
1308 root_lock = qdisc_lock(q);
1309 spin_lock_bh(root_lock);
1310
1311 val = (qdisc_is_running(q) ||
1312 test_bit(__QDISC_STATE_SCHED, &q->state));
1313
1314 spin_unlock_bh(root_lock);
1315
1316 if (val)
1317 return true;
1318 }
1319 return false;
1320}
1321
1322/**
1323 * dev_deactivate_many - deactivate transmissions on several devices
1324 * @head: list of devices to deactivate
1325 *
1326 * This function returns only when all outstanding transmissions
1327 * have completed, unless all devices are in dismantle phase.
1328 */
1329void dev_deactivate_many(struct list_head *head)
1330{
1331 struct net_device *dev;
1332
1333 list_for_each_entry(dev, head, close_list) {
1334 netdev_for_each_tx_queue(dev, dev_deactivate_queue,
1335 &noop_qdisc);
1336 if (dev_ingress_queue(dev))
1337 dev_deactivate_queue(dev, dev_ingress_queue(dev),
1338 &noop_qdisc);
1339
1340 dev_watchdog_down(dev);
1341 }
1342
1343 /* Wait for outstanding qdisc-less dev_queue_xmit calls or
1344 * outstanding qdisc enqueuing calls.
1345 * This is avoided if all devices are in dismantle phase :
1346 * Caller will call synchronize_net() for us
1347 */
1348 synchronize_net();
1349
1350 list_for_each_entry(dev, head, close_list) {
1351 netdev_for_each_tx_queue(dev, dev_reset_queue, NULL);
1352
1353 if (dev_ingress_queue(dev))
1354 dev_reset_queue(dev, dev_ingress_queue(dev), NULL);
1355 }
1356
1357 /* Wait for outstanding qdisc_run calls. */
1358 list_for_each_entry(dev, head, close_list) {
1359 while (some_qdisc_is_busy(dev)) {
1360 /* wait_event() would avoid this sleep-loop but would
1361 * require expensive checks in the fast paths of packet
1362 * processing which isn't worth it.
1363 */
1364 schedule_timeout_uninterruptible(1);
1365 }
1366 }
1367}
1368
1369void dev_deactivate(struct net_device *dev)
1370{
1371 LIST_HEAD(single);
1372
1373 list_add(&dev->close_list, &single);
1374 dev_deactivate_many(&single);
1375 list_del(&single);
1376}
1377EXPORT_SYMBOL(dev_deactivate);
1378
1379static int qdisc_change_tx_queue_len(struct net_device *dev,
1380 struct netdev_queue *dev_queue)
1381{
1382 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1383 const struct Qdisc_ops *ops = qdisc->ops;
1384
1385 if (ops->change_tx_queue_len)
1386 return ops->change_tx_queue_len(qdisc, dev->tx_queue_len);
1387 return 0;
1388}
1389
1390void dev_qdisc_change_real_num_tx(struct net_device *dev,
1391 unsigned int new_real_tx)
1392{
1393 struct Qdisc *qdisc = rtnl_dereference(dev->qdisc);
1394
1395 if (qdisc->ops->change_real_num_tx)
1396 qdisc->ops->change_real_num_tx(qdisc, new_real_tx);
1397}
1398
1399void mq_change_real_num_tx(struct Qdisc *sch, unsigned int new_real_tx)
1400{
1401#ifdef CONFIG_NET_SCHED
1402 struct net_device *dev = qdisc_dev(sch);
1403 struct Qdisc *qdisc;
1404 unsigned int i;
1405
1406 for (i = new_real_tx; i < dev->real_num_tx_queues; i++) {
1407 qdisc = netdev_get_tx_queue(dev, i)->qdisc_sleeping;
1408 /* Only update the default qdiscs we created,
1409 * qdiscs with handles are always hashed.
1410 */
1411 if (qdisc != &noop_qdisc && !qdisc->handle)
1412 qdisc_hash_del(qdisc);
1413 }
1414 for (i = dev->real_num_tx_queues; i < new_real_tx; i++) {
1415 qdisc = netdev_get_tx_queue(dev, i)->qdisc_sleeping;
1416 if (qdisc != &noop_qdisc && !qdisc->handle)
1417 qdisc_hash_add(qdisc, false);
1418 }
1419#endif
1420}
1421EXPORT_SYMBOL(mq_change_real_num_tx);
1422
1423int dev_qdisc_change_tx_queue_len(struct net_device *dev)
1424{
1425 bool up = dev->flags & IFF_UP;
1426 unsigned int i;
1427 int ret = 0;
1428
1429 if (up)
1430 dev_deactivate(dev);
1431
1432 for (i = 0; i < dev->num_tx_queues; i++) {
1433 ret = qdisc_change_tx_queue_len(dev, &dev->_tx[i]);
1434
1435 /* TODO: revert changes on a partial failure */
1436 if (ret)
1437 break;
1438 }
1439
1440 if (up)
1441 dev_activate(dev);
1442 return ret;
1443}
1444
1445static void dev_init_scheduler_queue(struct net_device *dev,
1446 struct netdev_queue *dev_queue,
1447 void *_qdisc)
1448{
1449 struct Qdisc *qdisc = _qdisc;
1450
1451 rcu_assign_pointer(dev_queue->qdisc, qdisc);
1452 dev_queue->qdisc_sleeping = qdisc;
1453}
1454
1455void dev_init_scheduler(struct net_device *dev)
1456{
1457 rcu_assign_pointer(dev->qdisc, &noop_qdisc);
1458 netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
1459 if (dev_ingress_queue(dev))
1460 dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1461
1462 timer_setup(&dev->watchdog_timer, dev_watchdog, 0);
1463}
1464
1465void dev_shutdown(struct net_device *dev)
1466{
1467 netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
1468 if (dev_ingress_queue(dev))
1469 shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1470 qdisc_put(rtnl_dereference(dev->qdisc));
1471 rcu_assign_pointer(dev->qdisc, &noop_qdisc);
1472
1473 WARN_ON(timer_pending(&dev->watchdog_timer));
1474}
1475
1476/**
1477 * psched_ratecfg_precompute__() - Pre-compute values for reciprocal division
1478 * @rate: Rate to compute reciprocal division values of
1479 * @mult: Multiplier for reciprocal division
1480 * @shift: Shift for reciprocal division
1481 *
1482 * The multiplier and shift for reciprocal division by rate are stored
1483 * in mult and shift.
1484 *
1485 * The deal here is to replace a divide by a reciprocal one
1486 * in fast path (a reciprocal divide is a multiply and a shift)
1487 *
1488 * Normal formula would be :
1489 * time_in_ns = (NSEC_PER_SEC * len) / rate_bps
1490 *
1491 * We compute mult/shift to use instead :
1492 * time_in_ns = (len * mult) >> shift;
1493 *
1494 * We try to get the highest possible mult value for accuracy,
1495 * but have to make sure no overflows will ever happen.
1496 *
1497 * reciprocal_value() is not used here it doesn't handle 64-bit values.
1498 */
1499static void psched_ratecfg_precompute__(u64 rate, u32 *mult, u8 *shift)
1500{
1501 u64 factor = NSEC_PER_SEC;
1502
1503 *mult = 1;
1504 *shift = 0;
1505
1506 if (rate <= 0)
1507 return;
1508
1509 for (;;) {
1510 *mult = div64_u64(factor, rate);
1511 if (*mult & (1U << 31) || factor & (1ULL << 63))
1512 break;
1513 factor <<= 1;
1514 (*shift)++;
1515 }
1516}
1517
1518void psched_ratecfg_precompute(struct psched_ratecfg *r,
1519 const struct tc_ratespec *conf,
1520 u64 rate64)
1521{
1522 memset(r, 0, sizeof(*r));
1523 r->overhead = conf->overhead;
1524 r->mpu = conf->mpu;
1525 r->rate_bytes_ps = max_t(u64, conf->rate, rate64);
1526 r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK);
1527 psched_ratecfg_precompute__(r->rate_bytes_ps, &r->mult, &r->shift);
1528}
1529EXPORT_SYMBOL(psched_ratecfg_precompute);
1530
1531void psched_ppscfg_precompute(struct psched_pktrate *r, u64 pktrate64)
1532{
1533 r->rate_pkts_ps = pktrate64;
1534 psched_ratecfg_precompute__(r->rate_pkts_ps, &r->mult, &r->shift);
1535}
1536EXPORT_SYMBOL(psched_ppscfg_precompute);
1537
1538void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp,
1539 struct tcf_proto *tp_head)
1540{
1541 /* Protected with chain0->filter_chain_lock.
1542 * Can't access chain directly because tp_head can be NULL.
1543 */
1544 struct mini_Qdisc *miniq_old =
1545 rcu_dereference_protected(*miniqp->p_miniq, 1);
1546 struct mini_Qdisc *miniq;
1547
1548 if (!tp_head) {
1549 RCU_INIT_POINTER(*miniqp->p_miniq, NULL);
1550 } else {
1551 miniq = miniq_old != &miniqp->miniq1 ?
1552 &miniqp->miniq1 : &miniqp->miniq2;
1553
1554 /* We need to make sure that readers won't see the miniq
1555 * we are about to modify. So ensure that at least one RCU
1556 * grace period has elapsed since the miniq was made
1557 * inactive.
1558 */
1559 if (IS_ENABLED(CONFIG_PREEMPT_RT))
1560 cond_synchronize_rcu(miniq->rcu_state);
1561 else if (!poll_state_synchronize_rcu(miniq->rcu_state))
1562 synchronize_rcu_expedited();
1563
1564 miniq->filter_list = tp_head;
1565 rcu_assign_pointer(*miniqp->p_miniq, miniq);
1566 }
1567
1568 if (miniq_old)
1569 /* This is counterpart of the rcu sync above. We need to
1570 * block potential new user of miniq_old until all readers
1571 * are not seeing it.
1572 */
1573 miniq_old->rcu_state = start_poll_synchronize_rcu();
1574}
1575EXPORT_SYMBOL(mini_qdisc_pair_swap);
1576
1577void mini_qdisc_pair_block_init(struct mini_Qdisc_pair *miniqp,
1578 struct tcf_block *block)
1579{
1580 miniqp->miniq1.block = block;
1581 miniqp->miniq2.block = block;
1582}
1583EXPORT_SYMBOL(mini_qdisc_pair_block_init);
1584
1585void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc,
1586 struct mini_Qdisc __rcu **p_miniq)
1587{
1588 miniqp->miniq1.cpu_bstats = qdisc->cpu_bstats;
1589 miniqp->miniq1.cpu_qstats = qdisc->cpu_qstats;
1590 miniqp->miniq2.cpu_bstats = qdisc->cpu_bstats;
1591 miniqp->miniq2.cpu_qstats = qdisc->cpu_qstats;
1592 miniqp->miniq1.rcu_state = get_state_synchronize_rcu();
1593 miniqp->miniq2.rcu_state = miniqp->miniq1.rcu_state;
1594 miniqp->p_miniq = p_miniq;
1595}
1596EXPORT_SYMBOL(mini_qdisc_pair_init);