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