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