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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 /*
386 * Ordered by possible occurrence: Postpone processing if
387 * 1. we've exceeded packet quota
388 * 2. another process needs the CPU;
389 */
390 quota -= packets;
391 if (quota <= 0 || need_resched()) {
392 __netif_schedule(q);
393 break;
394 }
395 }
396}
397
398unsigned long dev_trans_start(struct net_device *dev)
399{
400 unsigned long val, res;
401 unsigned int i;
402
403 if (is_vlan_dev(dev))
404 dev = vlan_dev_real_dev(dev);
405 else if (netif_is_macvlan(dev))
406 dev = macvlan_dev_real_dev(dev);
407 res = netdev_get_tx_queue(dev, 0)->trans_start;
408 for (i = 1; i < dev->num_tx_queues; i++) {
409 val = netdev_get_tx_queue(dev, i)->trans_start;
410 if (val && time_after(val, res))
411 res = val;
412 }
413
414 return res;
415}
416EXPORT_SYMBOL(dev_trans_start);
417
418static void dev_watchdog(struct timer_list *t)
419{
420 struct net_device *dev = from_timer(dev, t, watchdog_timer);
421
422 netif_tx_lock(dev);
423 if (!qdisc_tx_is_noop(dev)) {
424 if (netif_device_present(dev) &&
425 netif_running(dev) &&
426 netif_carrier_ok(dev)) {
427 int some_queue_timedout = 0;
428 unsigned int i;
429 unsigned long trans_start;
430
431 for (i = 0; i < dev->num_tx_queues; i++) {
432 struct netdev_queue *txq;
433
434 txq = netdev_get_tx_queue(dev, i);
435 trans_start = txq->trans_start;
436 if (netif_xmit_stopped(txq) &&
437 time_after(jiffies, (trans_start +
438 dev->watchdog_timeo))) {
439 some_queue_timedout = 1;
440 txq->trans_timeout++;
441 break;
442 }
443 }
444
445 if (some_queue_timedout) {
446 trace_net_dev_xmit_timeout(dev, i);
447 WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",
448 dev->name, netdev_drivername(dev), i);
449 dev->netdev_ops->ndo_tx_timeout(dev);
450 }
451 if (!mod_timer(&dev->watchdog_timer,
452 round_jiffies(jiffies +
453 dev->watchdog_timeo)))
454 dev_hold(dev);
455 }
456 }
457 netif_tx_unlock(dev);
458
459 dev_put(dev);
460}
461
462void __netdev_watchdog_up(struct net_device *dev)
463{
464 if (dev->netdev_ops->ndo_tx_timeout) {
465 if (dev->watchdog_timeo <= 0)
466 dev->watchdog_timeo = 5*HZ;
467 if (!mod_timer(&dev->watchdog_timer,
468 round_jiffies(jiffies + dev->watchdog_timeo)))
469 dev_hold(dev);
470 }
471}
472
473static void dev_watchdog_up(struct net_device *dev)
474{
475 __netdev_watchdog_up(dev);
476}
477
478static void dev_watchdog_down(struct net_device *dev)
479{
480 netif_tx_lock_bh(dev);
481 if (del_timer(&dev->watchdog_timer))
482 dev_put(dev);
483 netif_tx_unlock_bh(dev);
484}
485
486/**
487 * netif_carrier_on - set carrier
488 * @dev: network device
489 *
490 * Device has detected acquisition of carrier.
491 */
492void netif_carrier_on(struct net_device *dev)
493{
494 if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
495 if (dev->reg_state == NETREG_UNINITIALIZED)
496 return;
497 atomic_inc(&dev->carrier_up_count);
498 linkwatch_fire_event(dev);
499 if (netif_running(dev))
500 __netdev_watchdog_up(dev);
501 }
502}
503EXPORT_SYMBOL(netif_carrier_on);
504
505/**
506 * netif_carrier_off - clear carrier
507 * @dev: network device
508 *
509 * Device has detected loss of carrier.
510 */
511void netif_carrier_off(struct net_device *dev)
512{
513 if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
514 if (dev->reg_state == NETREG_UNINITIALIZED)
515 return;
516 atomic_inc(&dev->carrier_down_count);
517 linkwatch_fire_event(dev);
518 }
519}
520EXPORT_SYMBOL(netif_carrier_off);
521
522/* "NOOP" scheduler: the best scheduler, recommended for all interfaces
523 under all circumstances. It is difficult to invent anything faster or
524 cheaper.
525 */
526
527static int noop_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
528 struct sk_buff **to_free)
529{
530 __qdisc_drop(skb, to_free);
531 return NET_XMIT_CN;
532}
533
534static struct sk_buff *noop_dequeue(struct Qdisc *qdisc)
535{
536 return NULL;
537}
538
539struct Qdisc_ops noop_qdisc_ops __read_mostly = {
540 .id = "noop",
541 .priv_size = 0,
542 .enqueue = noop_enqueue,
543 .dequeue = noop_dequeue,
544 .peek = noop_dequeue,
545 .owner = THIS_MODULE,
546};
547
548static struct netdev_queue noop_netdev_queue = {
549 RCU_POINTER_INITIALIZER(qdisc, &noop_qdisc),
550 .qdisc_sleeping = &noop_qdisc,
551};
552
553struct Qdisc noop_qdisc = {
554 .enqueue = noop_enqueue,
555 .dequeue = noop_dequeue,
556 .flags = TCQ_F_BUILTIN,
557 .ops = &noop_qdisc_ops,
558 .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
559 .dev_queue = &noop_netdev_queue,
560 .running = SEQCNT_ZERO(noop_qdisc.running),
561 .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
562 .gso_skb = {
563 .next = (struct sk_buff *)&noop_qdisc.gso_skb,
564 .prev = (struct sk_buff *)&noop_qdisc.gso_skb,
565 .qlen = 0,
566 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.gso_skb.lock),
567 },
568 .skb_bad_txq = {
569 .next = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
570 .prev = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
571 .qlen = 0,
572 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.skb_bad_txq.lock),
573 },
574};
575EXPORT_SYMBOL(noop_qdisc);
576
577static int noqueue_init(struct Qdisc *qdisc, struct nlattr *opt,
578 struct netlink_ext_ack *extack)
579{
580 /* register_qdisc() assigns a default of noop_enqueue if unset,
581 * but __dev_queue_xmit() treats noqueue only as such
582 * if this is NULL - so clear it here. */
583 qdisc->enqueue = NULL;
584 return 0;
585}
586
587struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
588 .id = "noqueue",
589 .priv_size = 0,
590 .init = noqueue_init,
591 .enqueue = noop_enqueue,
592 .dequeue = noop_dequeue,
593 .peek = noop_dequeue,
594 .owner = THIS_MODULE,
595};
596
597static const u8 prio2band[TC_PRIO_MAX + 1] = {
598 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1
599};
600
601/* 3-band FIFO queue: old style, but should be a bit faster than
602 generic prio+fifo combination.
603 */
604
605#define PFIFO_FAST_BANDS 3
606
607/*
608 * Private data for a pfifo_fast scheduler containing:
609 * - rings for priority bands
610 */
611struct pfifo_fast_priv {
612 struct skb_array q[PFIFO_FAST_BANDS];
613};
614
615static inline struct skb_array *band2list(struct pfifo_fast_priv *priv,
616 int band)
617{
618 return &priv->q[band];
619}
620
621static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
622 struct sk_buff **to_free)
623{
624 int band = prio2band[skb->priority & TC_PRIO_MAX];
625 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
626 struct skb_array *q = band2list(priv, band);
627 unsigned int pkt_len = qdisc_pkt_len(skb);
628 int err;
629
630 err = skb_array_produce(q, skb);
631
632 if (unlikely(err)) {
633 if (qdisc_is_percpu_stats(qdisc))
634 return qdisc_drop_cpu(skb, qdisc, to_free);
635 else
636 return qdisc_drop(skb, qdisc, to_free);
637 }
638
639 qdisc_update_stats_at_enqueue(qdisc, pkt_len);
640 return NET_XMIT_SUCCESS;
641}
642
643static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
644{
645 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
646 struct sk_buff *skb = NULL;
647 int band;
648
649 for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
650 struct skb_array *q = band2list(priv, band);
651
652 if (__skb_array_empty(q))
653 continue;
654
655 skb = __skb_array_consume(q);
656 }
657 if (likely(skb)) {
658 qdisc_update_stats_at_dequeue(qdisc, skb);
659 } else {
660 qdisc->empty = true;
661 }
662
663 return skb;
664}
665
666static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
667{
668 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
669 struct sk_buff *skb = NULL;
670 int band;
671
672 for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
673 struct skb_array *q = band2list(priv, band);
674
675 skb = __skb_array_peek(q);
676 }
677
678 return skb;
679}
680
681static void pfifo_fast_reset(struct Qdisc *qdisc)
682{
683 int i, band;
684 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
685
686 for (band = 0; band < PFIFO_FAST_BANDS; band++) {
687 struct skb_array *q = band2list(priv, band);
688 struct sk_buff *skb;
689
690 /* NULL ring is possible if destroy path is due to a failed
691 * skb_array_init() in pfifo_fast_init() case.
692 */
693 if (!q->ring.queue)
694 continue;
695
696 while ((skb = __skb_array_consume(q)) != NULL)
697 kfree_skb(skb);
698 }
699
700 if (qdisc_is_percpu_stats(qdisc)) {
701 for_each_possible_cpu(i) {
702 struct gnet_stats_queue *q;
703
704 q = per_cpu_ptr(qdisc->cpu_qstats, i);
705 q->backlog = 0;
706 q->qlen = 0;
707 }
708 }
709}
710
711static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
712{
713 struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
714
715 memcpy(&opt.priomap, prio2band, TC_PRIO_MAX + 1);
716 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
717 goto nla_put_failure;
718 return skb->len;
719
720nla_put_failure:
721 return -1;
722}
723
724static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt,
725 struct netlink_ext_ack *extack)
726{
727 unsigned int qlen = qdisc_dev(qdisc)->tx_queue_len;
728 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
729 int prio;
730
731 /* guard against zero length rings */
732 if (!qlen)
733 return -EINVAL;
734
735 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
736 struct skb_array *q = band2list(priv, prio);
737 int err;
738
739 err = skb_array_init(q, qlen, GFP_KERNEL);
740 if (err)
741 return -ENOMEM;
742 }
743
744 /* Can by-pass the queue discipline */
745 qdisc->flags |= TCQ_F_CAN_BYPASS;
746 return 0;
747}
748
749static void pfifo_fast_destroy(struct Qdisc *sch)
750{
751 struct pfifo_fast_priv *priv = qdisc_priv(sch);
752 int prio;
753
754 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
755 struct skb_array *q = band2list(priv, prio);
756
757 /* NULL ring is possible if destroy path is due to a failed
758 * skb_array_init() in pfifo_fast_init() case.
759 */
760 if (!q->ring.queue)
761 continue;
762 /* Destroy ring but no need to kfree_skb because a call to
763 * pfifo_fast_reset() has already done that work.
764 */
765 ptr_ring_cleanup(&q->ring, NULL);
766 }
767}
768
769static int pfifo_fast_change_tx_queue_len(struct Qdisc *sch,
770 unsigned int new_len)
771{
772 struct pfifo_fast_priv *priv = qdisc_priv(sch);
773 struct skb_array *bands[PFIFO_FAST_BANDS];
774 int prio;
775
776 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
777 struct skb_array *q = band2list(priv, prio);
778
779 bands[prio] = q;
780 }
781
782 return skb_array_resize_multiple(bands, PFIFO_FAST_BANDS, new_len,
783 GFP_KERNEL);
784}
785
786struct Qdisc_ops pfifo_fast_ops __read_mostly = {
787 .id = "pfifo_fast",
788 .priv_size = sizeof(struct pfifo_fast_priv),
789 .enqueue = pfifo_fast_enqueue,
790 .dequeue = pfifo_fast_dequeue,
791 .peek = pfifo_fast_peek,
792 .init = pfifo_fast_init,
793 .destroy = pfifo_fast_destroy,
794 .reset = pfifo_fast_reset,
795 .dump = pfifo_fast_dump,
796 .change_tx_queue_len = pfifo_fast_change_tx_queue_len,
797 .owner = THIS_MODULE,
798 .static_flags = TCQ_F_NOLOCK | TCQ_F_CPUSTATS,
799};
800EXPORT_SYMBOL(pfifo_fast_ops);
801
802struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
803 const struct Qdisc_ops *ops,
804 struct netlink_ext_ack *extack)
805{
806 void *p;
807 struct Qdisc *sch;
808 unsigned int size = QDISC_ALIGN(sizeof(*sch)) + ops->priv_size;
809 int err = -ENOBUFS;
810 struct net_device *dev;
811
812 if (!dev_queue) {
813 NL_SET_ERR_MSG(extack, "No device queue given");
814 err = -EINVAL;
815 goto errout;
816 }
817
818 dev = dev_queue->dev;
819 p = kzalloc_node(size, GFP_KERNEL,
820 netdev_queue_numa_node_read(dev_queue));
821
822 if (!p)
823 goto errout;
824 sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
825 /* if we got non aligned memory, ask more and do alignment ourself */
826 if (sch != p) {
827 kfree(p);
828 p = kzalloc_node(size + QDISC_ALIGNTO - 1, GFP_KERNEL,
829 netdev_queue_numa_node_read(dev_queue));
830 if (!p)
831 goto errout;
832 sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
833 sch->padded = (char *) sch - (char *) p;
834 }
835 __skb_queue_head_init(&sch->gso_skb);
836 __skb_queue_head_init(&sch->skb_bad_txq);
837 qdisc_skb_head_init(&sch->q);
838 spin_lock_init(&sch->q.lock);
839
840 if (ops->static_flags & TCQ_F_CPUSTATS) {
841 sch->cpu_bstats =
842 netdev_alloc_pcpu_stats(struct gnet_stats_basic_cpu);
843 if (!sch->cpu_bstats)
844 goto errout1;
845
846 sch->cpu_qstats = alloc_percpu(struct gnet_stats_queue);
847 if (!sch->cpu_qstats) {
848 free_percpu(sch->cpu_bstats);
849 goto errout1;
850 }
851 }
852
853 spin_lock_init(&sch->busylock);
854 /* seqlock has the same scope of busylock, for NOLOCK qdisc */
855 spin_lock_init(&sch->seqlock);
856 seqcount_init(&sch->running);
857
858 sch->ops = ops;
859 sch->flags = ops->static_flags;
860 sch->enqueue = ops->enqueue;
861 sch->dequeue = ops->dequeue;
862 sch->dev_queue = dev_queue;
863 sch->empty = true;
864 dev_hold(dev);
865 refcount_set(&sch->refcnt, 1);
866
867 if (sch != &noop_qdisc) {
868 lockdep_set_class(&sch->busylock, &dev->qdisc_tx_busylock_key);
869 lockdep_set_class(&sch->seqlock, &dev->qdisc_tx_busylock_key);
870 lockdep_set_class(&sch->running, &dev->qdisc_running_key);
871 }
872
873 return sch;
874errout1:
875 kfree(p);
876errout:
877 return ERR_PTR(err);
878}
879
880struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
881 const struct Qdisc_ops *ops,
882 unsigned int parentid,
883 struct netlink_ext_ack *extack)
884{
885 struct Qdisc *sch;
886
887 if (!try_module_get(ops->owner)) {
888 NL_SET_ERR_MSG(extack, "Failed to increase module reference counter");
889 return NULL;
890 }
891
892 sch = qdisc_alloc(dev_queue, ops, extack);
893 if (IS_ERR(sch)) {
894 module_put(ops->owner);
895 return NULL;
896 }
897 sch->parent = parentid;
898
899 if (!ops->init || ops->init(sch, NULL, extack) == 0)
900 return sch;
901
902 qdisc_put(sch);
903 return NULL;
904}
905EXPORT_SYMBOL(qdisc_create_dflt);
906
907/* Under qdisc_lock(qdisc) and BH! */
908
909void qdisc_reset(struct Qdisc *qdisc)
910{
911 const struct Qdisc_ops *ops = qdisc->ops;
912 struct sk_buff *skb, *tmp;
913
914 if (ops->reset)
915 ops->reset(qdisc);
916
917 skb_queue_walk_safe(&qdisc->gso_skb, skb, tmp) {
918 __skb_unlink(skb, &qdisc->gso_skb);
919 kfree_skb_list(skb);
920 }
921
922 skb_queue_walk_safe(&qdisc->skb_bad_txq, skb, tmp) {
923 __skb_unlink(skb, &qdisc->skb_bad_txq);
924 kfree_skb_list(skb);
925 }
926
927 qdisc->q.qlen = 0;
928 qdisc->qstats.backlog = 0;
929}
930EXPORT_SYMBOL(qdisc_reset);
931
932void qdisc_free(struct Qdisc *qdisc)
933{
934 if (qdisc_is_percpu_stats(qdisc)) {
935 free_percpu(qdisc->cpu_bstats);
936 free_percpu(qdisc->cpu_qstats);
937 }
938
939 kfree((char *) qdisc - qdisc->padded);
940}
941
942static void qdisc_free_cb(struct rcu_head *head)
943{
944 struct Qdisc *q = container_of(head, struct Qdisc, rcu);
945
946 qdisc_free(q);
947}
948
949static void qdisc_destroy(struct Qdisc *qdisc)
950{
951 const struct Qdisc_ops *ops = qdisc->ops;
952 struct sk_buff *skb, *tmp;
953
954#ifdef CONFIG_NET_SCHED
955 qdisc_hash_del(qdisc);
956
957 qdisc_put_stab(rtnl_dereference(qdisc->stab));
958#endif
959 gen_kill_estimator(&qdisc->rate_est);
960 if (ops->reset)
961 ops->reset(qdisc);
962 if (ops->destroy)
963 ops->destroy(qdisc);
964
965 module_put(ops->owner);
966 dev_put(qdisc_dev(qdisc));
967
968 skb_queue_walk_safe(&qdisc->gso_skb, skb, tmp) {
969 __skb_unlink(skb, &qdisc->gso_skb);
970 kfree_skb_list(skb);
971 }
972
973 skb_queue_walk_safe(&qdisc->skb_bad_txq, skb, tmp) {
974 __skb_unlink(skb, &qdisc->skb_bad_txq);
975 kfree_skb_list(skb);
976 }
977
978 call_rcu(&qdisc->rcu, qdisc_free_cb);
979}
980
981void qdisc_put(struct Qdisc *qdisc)
982{
983 if (!qdisc)
984 return;
985
986 if (qdisc->flags & TCQ_F_BUILTIN ||
987 !refcount_dec_and_test(&qdisc->refcnt))
988 return;
989
990 qdisc_destroy(qdisc);
991}
992EXPORT_SYMBOL(qdisc_put);
993
994/* Version of qdisc_put() that is called with rtnl mutex unlocked.
995 * Intended to be used as optimization, this function only takes rtnl lock if
996 * qdisc reference counter reached zero.
997 */
998
999void qdisc_put_unlocked(struct Qdisc *qdisc)
1000{
1001 if (qdisc->flags & TCQ_F_BUILTIN ||
1002 !refcount_dec_and_rtnl_lock(&qdisc->refcnt))
1003 return;
1004
1005 qdisc_destroy(qdisc);
1006 rtnl_unlock();
1007}
1008EXPORT_SYMBOL(qdisc_put_unlocked);
1009
1010/* Attach toplevel qdisc to device queue. */
1011struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
1012 struct Qdisc *qdisc)
1013{
1014 struct Qdisc *oqdisc = dev_queue->qdisc_sleeping;
1015 spinlock_t *root_lock;
1016
1017 root_lock = qdisc_lock(oqdisc);
1018 spin_lock_bh(root_lock);
1019
1020 /* ... and graft new one */
1021 if (qdisc == NULL)
1022 qdisc = &noop_qdisc;
1023 dev_queue->qdisc_sleeping = qdisc;
1024 rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
1025
1026 spin_unlock_bh(root_lock);
1027
1028 return oqdisc;
1029}
1030EXPORT_SYMBOL(dev_graft_qdisc);
1031
1032static void attach_one_default_qdisc(struct net_device *dev,
1033 struct netdev_queue *dev_queue,
1034 void *_unused)
1035{
1036 struct Qdisc *qdisc;
1037 const struct Qdisc_ops *ops = default_qdisc_ops;
1038
1039 if (dev->priv_flags & IFF_NO_QUEUE)
1040 ops = &noqueue_qdisc_ops;
1041 else if(dev->type == ARPHRD_CAN)
1042 ops = &pfifo_fast_ops;
1043
1044 qdisc = qdisc_create_dflt(dev_queue, ops, TC_H_ROOT, NULL);
1045 if (!qdisc) {
1046 netdev_info(dev, "activation failed\n");
1047 return;
1048 }
1049 if (!netif_is_multiqueue(dev))
1050 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
1051 dev_queue->qdisc_sleeping = qdisc;
1052}
1053
1054static void attach_default_qdiscs(struct net_device *dev)
1055{
1056 struct netdev_queue *txq;
1057 struct Qdisc *qdisc;
1058
1059 txq = netdev_get_tx_queue(dev, 0);
1060
1061 if (!netif_is_multiqueue(dev) ||
1062 dev->priv_flags & IFF_NO_QUEUE) {
1063 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
1064 dev->qdisc = txq->qdisc_sleeping;
1065 qdisc_refcount_inc(dev->qdisc);
1066 } else {
1067 qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT, NULL);
1068 if (qdisc) {
1069 dev->qdisc = qdisc;
1070 qdisc->ops->attach(qdisc);
1071 }
1072 }
1073#ifdef CONFIG_NET_SCHED
1074 if (dev->qdisc != &noop_qdisc)
1075 qdisc_hash_add(dev->qdisc, false);
1076#endif
1077}
1078
1079static void transition_one_qdisc(struct net_device *dev,
1080 struct netdev_queue *dev_queue,
1081 void *_need_watchdog)
1082{
1083 struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
1084 int *need_watchdog_p = _need_watchdog;
1085
1086 if (!(new_qdisc->flags & TCQ_F_BUILTIN))
1087 clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
1088
1089 rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
1090 if (need_watchdog_p) {
1091 dev_queue->trans_start = 0;
1092 *need_watchdog_p = 1;
1093 }
1094}
1095
1096void dev_activate(struct net_device *dev)
1097{
1098 int need_watchdog;
1099
1100 /* No queueing discipline is attached to device;
1101 * create default one for devices, which need queueing
1102 * and noqueue_qdisc for virtual interfaces
1103 */
1104
1105 if (dev->qdisc == &noop_qdisc)
1106 attach_default_qdiscs(dev);
1107
1108 if (!netif_carrier_ok(dev))
1109 /* Delay activation until next carrier-on event */
1110 return;
1111
1112 need_watchdog = 0;
1113 netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
1114 if (dev_ingress_queue(dev))
1115 transition_one_qdisc(dev, dev_ingress_queue(dev), NULL);
1116
1117 if (need_watchdog) {
1118 netif_trans_update(dev);
1119 dev_watchdog_up(dev);
1120 }
1121}
1122EXPORT_SYMBOL(dev_activate);
1123
1124static void dev_deactivate_queue(struct net_device *dev,
1125 struct netdev_queue *dev_queue,
1126 void *_qdisc_default)
1127{
1128 struct Qdisc *qdisc_default = _qdisc_default;
1129 struct Qdisc *qdisc;
1130
1131 qdisc = rtnl_dereference(dev_queue->qdisc);
1132 if (qdisc) {
1133 bool nolock = qdisc->flags & TCQ_F_NOLOCK;
1134
1135 if (nolock)
1136 spin_lock_bh(&qdisc->seqlock);
1137 spin_lock_bh(qdisc_lock(qdisc));
1138
1139 if (!(qdisc->flags & TCQ_F_BUILTIN))
1140 set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
1141
1142 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1143 qdisc_reset(qdisc);
1144
1145 spin_unlock_bh(qdisc_lock(qdisc));
1146 if (nolock)
1147 spin_unlock_bh(&qdisc->seqlock);
1148 }
1149}
1150
1151static bool some_qdisc_is_busy(struct net_device *dev)
1152{
1153 unsigned int i;
1154
1155 for (i = 0; i < dev->num_tx_queues; i++) {
1156 struct netdev_queue *dev_queue;
1157 spinlock_t *root_lock;
1158 struct Qdisc *q;
1159 int val;
1160
1161 dev_queue = netdev_get_tx_queue(dev, i);
1162 q = dev_queue->qdisc_sleeping;
1163
1164 root_lock = qdisc_lock(q);
1165 spin_lock_bh(root_lock);
1166
1167 val = (qdisc_is_running(q) ||
1168 test_bit(__QDISC_STATE_SCHED, &q->state));
1169
1170 spin_unlock_bh(root_lock);
1171
1172 if (val)
1173 return true;
1174 }
1175 return false;
1176}
1177
1178static void dev_qdisc_reset(struct net_device *dev,
1179 struct netdev_queue *dev_queue,
1180 void *none)
1181{
1182 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1183
1184 if (qdisc)
1185 qdisc_reset(qdisc);
1186}
1187
1188/**
1189 * dev_deactivate_many - deactivate transmissions on several devices
1190 * @head: list of devices to deactivate
1191 *
1192 * This function returns only when all outstanding transmissions
1193 * have completed, unless all devices are in dismantle phase.
1194 */
1195void dev_deactivate_many(struct list_head *head)
1196{
1197 struct net_device *dev;
1198
1199 list_for_each_entry(dev, head, close_list) {
1200 netdev_for_each_tx_queue(dev, dev_deactivate_queue,
1201 &noop_qdisc);
1202 if (dev_ingress_queue(dev))
1203 dev_deactivate_queue(dev, dev_ingress_queue(dev),
1204 &noop_qdisc);
1205
1206 dev_watchdog_down(dev);
1207 }
1208
1209 /* Wait for outstanding qdisc-less dev_queue_xmit calls.
1210 * This is avoided if all devices are in dismantle phase :
1211 * Caller will call synchronize_net() for us
1212 */
1213 synchronize_net();
1214
1215 /* Wait for outstanding qdisc_run calls. */
1216 list_for_each_entry(dev, head, close_list) {
1217 while (some_qdisc_is_busy(dev))
1218 yield();
1219 /* The new qdisc is assigned at this point so we can safely
1220 * unwind stale skb lists and qdisc statistics
1221 */
1222 netdev_for_each_tx_queue(dev, dev_qdisc_reset, NULL);
1223 if (dev_ingress_queue(dev))
1224 dev_qdisc_reset(dev, dev_ingress_queue(dev), NULL);
1225 }
1226}
1227
1228void dev_deactivate(struct net_device *dev)
1229{
1230 LIST_HEAD(single);
1231
1232 list_add(&dev->close_list, &single);
1233 dev_deactivate_many(&single);
1234 list_del(&single);
1235}
1236EXPORT_SYMBOL(dev_deactivate);
1237
1238static int qdisc_change_tx_queue_len(struct net_device *dev,
1239 struct netdev_queue *dev_queue)
1240{
1241 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1242 const struct Qdisc_ops *ops = qdisc->ops;
1243
1244 if (ops->change_tx_queue_len)
1245 return ops->change_tx_queue_len(qdisc, dev->tx_queue_len);
1246 return 0;
1247}
1248
1249int dev_qdisc_change_tx_queue_len(struct net_device *dev)
1250{
1251 bool up = dev->flags & IFF_UP;
1252 unsigned int i;
1253 int ret = 0;
1254
1255 if (up)
1256 dev_deactivate(dev);
1257
1258 for (i = 0; i < dev->num_tx_queues; i++) {
1259 ret = qdisc_change_tx_queue_len(dev, &dev->_tx[i]);
1260
1261 /* TODO: revert changes on a partial failure */
1262 if (ret)
1263 break;
1264 }
1265
1266 if (up)
1267 dev_activate(dev);
1268 return ret;
1269}
1270
1271static void dev_init_scheduler_queue(struct net_device *dev,
1272 struct netdev_queue *dev_queue,
1273 void *_qdisc)
1274{
1275 struct Qdisc *qdisc = _qdisc;
1276
1277 rcu_assign_pointer(dev_queue->qdisc, qdisc);
1278 dev_queue->qdisc_sleeping = qdisc;
1279}
1280
1281void dev_init_scheduler(struct net_device *dev)
1282{
1283 dev->qdisc = &noop_qdisc;
1284 netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
1285 if (dev_ingress_queue(dev))
1286 dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1287
1288 timer_setup(&dev->watchdog_timer, dev_watchdog, 0);
1289}
1290
1291static void shutdown_scheduler_queue(struct net_device *dev,
1292 struct netdev_queue *dev_queue,
1293 void *_qdisc_default)
1294{
1295 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1296 struct Qdisc *qdisc_default = _qdisc_default;
1297
1298 if (qdisc) {
1299 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1300 dev_queue->qdisc_sleeping = qdisc_default;
1301
1302 qdisc_put(qdisc);
1303 }
1304}
1305
1306void dev_shutdown(struct net_device *dev)
1307{
1308 netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
1309 if (dev_ingress_queue(dev))
1310 shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1311 qdisc_put(dev->qdisc);
1312 dev->qdisc = &noop_qdisc;
1313
1314 WARN_ON(timer_pending(&dev->watchdog_timer));
1315}
1316
1317void psched_ratecfg_precompute(struct psched_ratecfg *r,
1318 const struct tc_ratespec *conf,
1319 u64 rate64)
1320{
1321 memset(r, 0, sizeof(*r));
1322 r->overhead = conf->overhead;
1323 r->rate_bytes_ps = max_t(u64, conf->rate, rate64);
1324 r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK);
1325 r->mult = 1;
1326 /*
1327 * The deal here is to replace a divide by a reciprocal one
1328 * in fast path (a reciprocal divide is a multiply and a shift)
1329 *
1330 * Normal formula would be :
1331 * time_in_ns = (NSEC_PER_SEC * len) / rate_bps
1332 *
1333 * We compute mult/shift to use instead :
1334 * time_in_ns = (len * mult) >> shift;
1335 *
1336 * We try to get the highest possible mult value for accuracy,
1337 * but have to make sure no overflows will ever happen.
1338 */
1339 if (r->rate_bytes_ps > 0) {
1340 u64 factor = NSEC_PER_SEC;
1341
1342 for (;;) {
1343 r->mult = div64_u64(factor, r->rate_bytes_ps);
1344 if (r->mult & (1U << 31) || factor & (1ULL << 63))
1345 break;
1346 factor <<= 1;
1347 r->shift++;
1348 }
1349 }
1350}
1351EXPORT_SYMBOL(psched_ratecfg_precompute);
1352
1353static void mini_qdisc_rcu_func(struct rcu_head *head)
1354{
1355}
1356
1357void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp,
1358 struct tcf_proto *tp_head)
1359{
1360 /* Protected with chain0->filter_chain_lock.
1361 * Can't access chain directly because tp_head can be NULL.
1362 */
1363 struct mini_Qdisc *miniq_old =
1364 rcu_dereference_protected(*miniqp->p_miniq, 1);
1365 struct mini_Qdisc *miniq;
1366
1367 if (!tp_head) {
1368 RCU_INIT_POINTER(*miniqp->p_miniq, NULL);
1369 /* Wait for flying RCU callback before it is freed. */
1370 rcu_barrier();
1371 return;
1372 }
1373
1374 miniq = !miniq_old || miniq_old == &miniqp->miniq2 ?
1375 &miniqp->miniq1 : &miniqp->miniq2;
1376
1377 /* We need to make sure that readers won't see the miniq
1378 * we are about to modify. So wait until previous call_rcu callback
1379 * is done.
1380 */
1381 rcu_barrier();
1382 miniq->filter_list = tp_head;
1383 rcu_assign_pointer(*miniqp->p_miniq, miniq);
1384
1385 if (miniq_old)
1386 /* This is counterpart of the rcu barriers above. We need to
1387 * block potential new user of miniq_old until all readers
1388 * are not seeing it.
1389 */
1390 call_rcu(&miniq_old->rcu, mini_qdisc_rcu_func);
1391}
1392EXPORT_SYMBOL(mini_qdisc_pair_swap);
1393
1394void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc,
1395 struct mini_Qdisc __rcu **p_miniq)
1396{
1397 miniqp->miniq1.cpu_bstats = qdisc->cpu_bstats;
1398 miniqp->miniq1.cpu_qstats = qdisc->cpu_qstats;
1399 miniqp->miniq2.cpu_bstats = qdisc->cpu_bstats;
1400 miniqp->miniq2.cpu_qstats = qdisc->cpu_qstats;
1401 miniqp->p_miniq = p_miniq;
1402}
1403EXPORT_SYMBOL(mini_qdisc_pair_init);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/sch_generic.c Generic packet scheduler routines.
4 *
5 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6 * Jamal Hadi Salim, <hadi@cyberus.ca> 990601
7 * - Ingress support
8 */
9
10#include <linux/bitops.h>
11#include <linux/module.h>
12#include <linux/types.h>
13#include <linux/kernel.h>
14#include <linux/sched.h>
15#include <linux/string.h>
16#include <linux/errno.h>
17#include <linux/netdevice.h>
18#include <linux/skbuff.h>
19#include <linux/rtnetlink.h>
20#include <linux/init.h>
21#include <linux/rcupdate.h>
22#include <linux/list.h>
23#include <linux/slab.h>
24#include <linux/if_vlan.h>
25#include <linux/skb_array.h>
26#include <linux/if_macvlan.h>
27#include <net/sch_generic.h>
28#include <net/pkt_sched.h>
29#include <net/dst.h>
30#include <trace/events/qdisc.h>
31#include <trace/events/net.h>
32#include <net/xfrm.h>
33
34/* Qdisc to use by default */
35const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops;
36EXPORT_SYMBOL(default_qdisc_ops);
37
38static void qdisc_maybe_clear_missed(struct Qdisc *q,
39 const struct netdev_queue *txq)
40{
41 clear_bit(__QDISC_STATE_MISSED, &q->state);
42
43 /* Make sure the below netif_xmit_frozen_or_stopped()
44 * checking happens after clearing STATE_MISSED.
45 */
46 smp_mb__after_atomic();
47
48 /* Checking netif_xmit_frozen_or_stopped() again to
49 * make sure STATE_MISSED is set if the STATE_MISSED
50 * set by netif_tx_wake_queue()'s rescheduling of
51 * net_tx_action() is cleared by the above clear_bit().
52 */
53 if (!netif_xmit_frozen_or_stopped(txq))
54 set_bit(__QDISC_STATE_MISSED, &q->state);
55 else
56 set_bit(__QDISC_STATE_DRAINING, &q->state);
57}
58
59/* Main transmission queue. */
60
61/* Modifications to data participating in scheduling must be protected with
62 * qdisc_lock(qdisc) spinlock.
63 *
64 * The idea is the following:
65 * - enqueue, dequeue are serialized via qdisc root lock
66 * - ingress filtering is also serialized via qdisc root lock
67 * - updates to tree and tree walking are only done under the rtnl mutex.
68 */
69
70#define SKB_XOFF_MAGIC ((struct sk_buff *)1UL)
71
72static inline struct sk_buff *__skb_dequeue_bad_txq(struct Qdisc *q)
73{
74 const struct netdev_queue *txq = q->dev_queue;
75 spinlock_t *lock = NULL;
76 struct sk_buff *skb;
77
78 if (q->flags & TCQ_F_NOLOCK) {
79 lock = qdisc_lock(q);
80 spin_lock(lock);
81 }
82
83 skb = skb_peek(&q->skb_bad_txq);
84 if (skb) {
85 /* check the reason of requeuing without tx lock first */
86 txq = skb_get_tx_queue(txq->dev, skb);
87 if (!netif_xmit_frozen_or_stopped(txq)) {
88 skb = __skb_dequeue(&q->skb_bad_txq);
89 if (qdisc_is_percpu_stats(q)) {
90 qdisc_qstats_cpu_backlog_dec(q, skb);
91 qdisc_qstats_cpu_qlen_dec(q);
92 } else {
93 qdisc_qstats_backlog_dec(q, skb);
94 q->q.qlen--;
95 }
96 } else {
97 skb = SKB_XOFF_MAGIC;
98 qdisc_maybe_clear_missed(q, txq);
99 }
100 }
101
102 if (lock)
103 spin_unlock(lock);
104
105 return skb;
106}
107
108static inline struct sk_buff *qdisc_dequeue_skb_bad_txq(struct Qdisc *q)
109{
110 struct sk_buff *skb = skb_peek(&q->skb_bad_txq);
111
112 if (unlikely(skb))
113 skb = __skb_dequeue_bad_txq(q);
114
115 return skb;
116}
117
118static inline void qdisc_enqueue_skb_bad_txq(struct Qdisc *q,
119 struct sk_buff *skb)
120{
121 spinlock_t *lock = NULL;
122
123 if (q->flags & TCQ_F_NOLOCK) {
124 lock = qdisc_lock(q);
125 spin_lock(lock);
126 }
127
128 __skb_queue_tail(&q->skb_bad_txq, skb);
129
130 if (qdisc_is_percpu_stats(q)) {
131 qdisc_qstats_cpu_backlog_inc(q, skb);
132 qdisc_qstats_cpu_qlen_inc(q);
133 } else {
134 qdisc_qstats_backlog_inc(q, skb);
135 q->q.qlen++;
136 }
137
138 if (lock)
139 spin_unlock(lock);
140}
141
142static inline void dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
143{
144 spinlock_t *lock = NULL;
145
146 if (q->flags & TCQ_F_NOLOCK) {
147 lock = qdisc_lock(q);
148 spin_lock(lock);
149 }
150
151 while (skb) {
152 struct sk_buff *next = skb->next;
153
154 __skb_queue_tail(&q->gso_skb, skb);
155
156 /* it's still part of the queue */
157 if (qdisc_is_percpu_stats(q)) {
158 qdisc_qstats_cpu_requeues_inc(q);
159 qdisc_qstats_cpu_backlog_inc(q, skb);
160 qdisc_qstats_cpu_qlen_inc(q);
161 } else {
162 q->qstats.requeues++;
163 qdisc_qstats_backlog_inc(q, skb);
164 q->q.qlen++;
165 }
166
167 skb = next;
168 }
169
170 if (lock) {
171 spin_unlock(lock);
172 set_bit(__QDISC_STATE_MISSED, &q->state);
173 } else {
174 __netif_schedule(q);
175 }
176}
177
178static void try_bulk_dequeue_skb(struct Qdisc *q,
179 struct sk_buff *skb,
180 const struct netdev_queue *txq,
181 int *packets)
182{
183 int bytelimit = qdisc_avail_bulklimit(txq) - skb->len;
184
185 while (bytelimit > 0) {
186 struct sk_buff *nskb = q->dequeue(q);
187
188 if (!nskb)
189 break;
190
191 bytelimit -= nskb->len; /* covers GSO len */
192 skb->next = nskb;
193 skb = nskb;
194 (*packets)++; /* GSO counts as one pkt */
195 }
196 skb_mark_not_on_list(skb);
197}
198
199/* This variant of try_bulk_dequeue_skb() makes sure
200 * all skbs in the chain are for the same txq
201 */
202static void try_bulk_dequeue_skb_slow(struct Qdisc *q,
203 struct sk_buff *skb,
204 int *packets)
205{
206 int mapping = skb_get_queue_mapping(skb);
207 struct sk_buff *nskb;
208 int cnt = 0;
209
210 do {
211 nskb = q->dequeue(q);
212 if (!nskb)
213 break;
214 if (unlikely(skb_get_queue_mapping(nskb) != mapping)) {
215 qdisc_enqueue_skb_bad_txq(q, nskb);
216 break;
217 }
218 skb->next = nskb;
219 skb = nskb;
220 } while (++cnt < 8);
221 (*packets) += cnt;
222 skb_mark_not_on_list(skb);
223}
224
225/* Note that dequeue_skb can possibly return a SKB list (via skb->next).
226 * A requeued skb (via q->gso_skb) can also be a SKB list.
227 */
228static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
229 int *packets)
230{
231 const struct netdev_queue *txq = q->dev_queue;
232 struct sk_buff *skb = NULL;
233
234 *packets = 1;
235 if (unlikely(!skb_queue_empty(&q->gso_skb))) {
236 spinlock_t *lock = NULL;
237
238 if (q->flags & TCQ_F_NOLOCK) {
239 lock = qdisc_lock(q);
240 spin_lock(lock);
241 }
242
243 skb = skb_peek(&q->gso_skb);
244
245 /* skb may be null if another cpu pulls gso_skb off in between
246 * empty check and lock.
247 */
248 if (!skb) {
249 if (lock)
250 spin_unlock(lock);
251 goto validate;
252 }
253
254 /* skb in gso_skb were already validated */
255 *validate = false;
256 if (xfrm_offload(skb))
257 *validate = true;
258 /* check the reason of requeuing without tx lock first */
259 txq = skb_get_tx_queue(txq->dev, skb);
260 if (!netif_xmit_frozen_or_stopped(txq)) {
261 skb = __skb_dequeue(&q->gso_skb);
262 if (qdisc_is_percpu_stats(q)) {
263 qdisc_qstats_cpu_backlog_dec(q, skb);
264 qdisc_qstats_cpu_qlen_dec(q);
265 } else {
266 qdisc_qstats_backlog_dec(q, skb);
267 q->q.qlen--;
268 }
269 } else {
270 skb = NULL;
271 qdisc_maybe_clear_missed(q, txq);
272 }
273 if (lock)
274 spin_unlock(lock);
275 goto trace;
276 }
277validate:
278 *validate = true;
279
280 if ((q->flags & TCQ_F_ONETXQUEUE) &&
281 netif_xmit_frozen_or_stopped(txq)) {
282 qdisc_maybe_clear_missed(q, txq);
283 return skb;
284 }
285
286 skb = qdisc_dequeue_skb_bad_txq(q);
287 if (unlikely(skb)) {
288 if (skb == SKB_XOFF_MAGIC)
289 return NULL;
290 goto bulk;
291 }
292 skb = q->dequeue(q);
293 if (skb) {
294bulk:
295 if (qdisc_may_bulk(q))
296 try_bulk_dequeue_skb(q, skb, txq, packets);
297 else
298 try_bulk_dequeue_skb_slow(q, skb, packets);
299 }
300trace:
301 trace_qdisc_dequeue(q, txq, *packets, skb);
302 return skb;
303}
304
305/*
306 * Transmit possibly several skbs, and handle the return status as
307 * required. Owning qdisc running bit guarantees that only one CPU
308 * can execute this function.
309 *
310 * Returns to the caller:
311 * false - hardware queue frozen backoff
312 * true - feel free to send more pkts
313 */
314bool sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
315 struct net_device *dev, struct netdev_queue *txq,
316 spinlock_t *root_lock, bool validate)
317{
318 int ret = NETDEV_TX_BUSY;
319 bool again = false;
320
321 /* And release qdisc */
322 if (root_lock)
323 spin_unlock(root_lock);
324
325 /* Note that we validate skb (GSO, checksum, ...) outside of locks */
326 if (validate)
327 skb = validate_xmit_skb_list(skb, dev, &again);
328
329#ifdef CONFIG_XFRM_OFFLOAD
330 if (unlikely(again)) {
331 if (root_lock)
332 spin_lock(root_lock);
333
334 dev_requeue_skb(skb, q);
335 return false;
336 }
337#endif
338
339 if (likely(skb)) {
340 HARD_TX_LOCK(dev, txq, smp_processor_id());
341 if (!netif_xmit_frozen_or_stopped(txq))
342 skb = dev_hard_start_xmit(skb, dev, txq, &ret);
343 else
344 qdisc_maybe_clear_missed(q, txq);
345
346 HARD_TX_UNLOCK(dev, txq);
347 } else {
348 if (root_lock)
349 spin_lock(root_lock);
350 return true;
351 }
352
353 if (root_lock)
354 spin_lock(root_lock);
355
356 if (!dev_xmit_complete(ret)) {
357 /* Driver returned NETDEV_TX_BUSY - requeue skb */
358 if (unlikely(ret != NETDEV_TX_BUSY))
359 net_warn_ratelimited("BUG %s code %d qlen %d\n",
360 dev->name, ret, q->q.qlen);
361
362 dev_requeue_skb(skb, q);
363 return false;
364 }
365
366 return true;
367}
368
369/*
370 * NOTE: Called under qdisc_lock(q) with locally disabled BH.
371 *
372 * running seqcount guarantees only one CPU can process
373 * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
374 * this queue.
375 *
376 * netif_tx_lock serializes accesses to device driver.
377 *
378 * qdisc_lock(q) and netif_tx_lock are mutually exclusive,
379 * if one is grabbed, another must be free.
380 *
381 * Note, that this procedure can be called by a watchdog timer
382 *
383 * Returns to the caller:
384 * 0 - queue is empty or throttled.
385 * >0 - queue is not empty.
386 *
387 */
388static inline bool qdisc_restart(struct Qdisc *q, int *packets)
389{
390 spinlock_t *root_lock = NULL;
391 struct netdev_queue *txq;
392 struct net_device *dev;
393 struct sk_buff *skb;
394 bool validate;
395
396 /* Dequeue packet */
397 skb = dequeue_skb(q, &validate, packets);
398 if (unlikely(!skb))
399 return false;
400
401 if (!(q->flags & TCQ_F_NOLOCK))
402 root_lock = qdisc_lock(q);
403
404 dev = qdisc_dev(q);
405 txq = skb_get_tx_queue(dev, skb);
406
407 return sch_direct_xmit(skb, q, dev, txq, root_lock, validate);
408}
409
410void __qdisc_run(struct Qdisc *q)
411{
412 int quota = READ_ONCE(dev_tx_weight);
413 int packets;
414
415 while (qdisc_restart(q, &packets)) {
416 quota -= packets;
417 if (quota <= 0) {
418 if (q->flags & TCQ_F_NOLOCK)
419 set_bit(__QDISC_STATE_MISSED, &q->state);
420 else
421 __netif_schedule(q);
422
423 break;
424 }
425 }
426}
427
428unsigned long dev_trans_start(struct net_device *dev)
429{
430 unsigned long res = READ_ONCE(netdev_get_tx_queue(dev, 0)->trans_start);
431 unsigned long val;
432 unsigned int i;
433
434 for (i = 1; i < dev->num_tx_queues; i++) {
435 val = READ_ONCE(netdev_get_tx_queue(dev, i)->trans_start);
436 if (val && time_after(val, res))
437 res = val;
438 }
439
440 return res;
441}
442EXPORT_SYMBOL(dev_trans_start);
443
444static void netif_freeze_queues(struct net_device *dev)
445{
446 unsigned int i;
447 int cpu;
448
449 cpu = smp_processor_id();
450 for (i = 0; i < dev->num_tx_queues; i++) {
451 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
452
453 /* We are the only thread of execution doing a
454 * freeze, but we have to grab the _xmit_lock in
455 * order to synchronize with threads which are in
456 * the ->hard_start_xmit() handler and already
457 * checked the frozen bit.
458 */
459 __netif_tx_lock(txq, cpu);
460 set_bit(__QUEUE_STATE_FROZEN, &txq->state);
461 __netif_tx_unlock(txq);
462 }
463}
464
465void netif_tx_lock(struct net_device *dev)
466{
467 spin_lock(&dev->tx_global_lock);
468 netif_freeze_queues(dev);
469}
470EXPORT_SYMBOL(netif_tx_lock);
471
472static void netif_unfreeze_queues(struct net_device *dev)
473{
474 unsigned int i;
475
476 for (i = 0; i < dev->num_tx_queues; i++) {
477 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
478
479 /* No need to grab the _xmit_lock here. If the
480 * queue is not stopped for another reason, we
481 * force a schedule.
482 */
483 clear_bit(__QUEUE_STATE_FROZEN, &txq->state);
484 netif_schedule_queue(txq);
485 }
486}
487
488void netif_tx_unlock(struct net_device *dev)
489{
490 netif_unfreeze_queues(dev);
491 spin_unlock(&dev->tx_global_lock);
492}
493EXPORT_SYMBOL(netif_tx_unlock);
494
495static void dev_watchdog(struct timer_list *t)
496{
497 struct net_device *dev = from_timer(dev, t, watchdog_timer);
498 bool release = true;
499
500 spin_lock(&dev->tx_global_lock);
501 if (!qdisc_tx_is_noop(dev)) {
502 if (netif_device_present(dev) &&
503 netif_running(dev) &&
504 netif_carrier_ok(dev)) {
505 int some_queue_timedout = 0;
506 unsigned int i;
507 unsigned long trans_start;
508
509 for (i = 0; i < dev->num_tx_queues; i++) {
510 struct netdev_queue *txq;
511
512 txq = netdev_get_tx_queue(dev, i);
513 trans_start = READ_ONCE(txq->trans_start);
514 if (netif_xmit_stopped(txq) &&
515 time_after(jiffies, (trans_start +
516 dev->watchdog_timeo))) {
517 some_queue_timedout = 1;
518 atomic_long_inc(&txq->trans_timeout);
519 break;
520 }
521 }
522
523 if (unlikely(some_queue_timedout)) {
524 trace_net_dev_xmit_timeout(dev, i);
525 WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",
526 dev->name, netdev_drivername(dev), i);
527 netif_freeze_queues(dev);
528 dev->netdev_ops->ndo_tx_timeout(dev, i);
529 netif_unfreeze_queues(dev);
530 }
531 if (!mod_timer(&dev->watchdog_timer,
532 round_jiffies(jiffies +
533 dev->watchdog_timeo)))
534 release = false;
535 }
536 }
537 spin_unlock(&dev->tx_global_lock);
538
539 if (release)
540 netdev_put(dev, &dev->watchdog_dev_tracker);
541}
542
543void __netdev_watchdog_up(struct net_device *dev)
544{
545 if (dev->netdev_ops->ndo_tx_timeout) {
546 if (dev->watchdog_timeo <= 0)
547 dev->watchdog_timeo = 5*HZ;
548 if (!mod_timer(&dev->watchdog_timer,
549 round_jiffies(jiffies + dev->watchdog_timeo)))
550 netdev_hold(dev, &dev->watchdog_dev_tracker,
551 GFP_ATOMIC);
552 }
553}
554EXPORT_SYMBOL_GPL(__netdev_watchdog_up);
555
556static void dev_watchdog_up(struct net_device *dev)
557{
558 __netdev_watchdog_up(dev);
559}
560
561static void dev_watchdog_down(struct net_device *dev)
562{
563 netif_tx_lock_bh(dev);
564 if (del_timer(&dev->watchdog_timer))
565 netdev_put(dev, &dev->watchdog_dev_tracker);
566 netif_tx_unlock_bh(dev);
567}
568
569/**
570 * netif_carrier_on - set carrier
571 * @dev: network device
572 *
573 * Device has detected acquisition of carrier.
574 */
575void netif_carrier_on(struct net_device *dev)
576{
577 if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
578 if (dev->reg_state == NETREG_UNINITIALIZED)
579 return;
580 atomic_inc(&dev->carrier_up_count);
581 linkwatch_fire_event(dev);
582 if (netif_running(dev))
583 __netdev_watchdog_up(dev);
584 }
585}
586EXPORT_SYMBOL(netif_carrier_on);
587
588/**
589 * netif_carrier_off - clear carrier
590 * @dev: network device
591 *
592 * Device has detected loss of carrier.
593 */
594void netif_carrier_off(struct net_device *dev)
595{
596 if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
597 if (dev->reg_state == NETREG_UNINITIALIZED)
598 return;
599 atomic_inc(&dev->carrier_down_count);
600 linkwatch_fire_event(dev);
601 }
602}
603EXPORT_SYMBOL(netif_carrier_off);
604
605/**
606 * netif_carrier_event - report carrier state event
607 * @dev: network device
608 *
609 * Device has detected a carrier event but the carrier state wasn't changed.
610 * Use in drivers when querying carrier state asynchronously, to avoid missing
611 * events (link flaps) if link recovers before it's queried.
612 */
613void netif_carrier_event(struct net_device *dev)
614{
615 if (dev->reg_state == NETREG_UNINITIALIZED)
616 return;
617 atomic_inc(&dev->carrier_up_count);
618 atomic_inc(&dev->carrier_down_count);
619 linkwatch_fire_event(dev);
620}
621EXPORT_SYMBOL_GPL(netif_carrier_event);
622
623/* "NOOP" scheduler: the best scheduler, recommended for all interfaces
624 under all circumstances. It is difficult to invent anything faster or
625 cheaper.
626 */
627
628static int noop_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
629 struct sk_buff **to_free)
630{
631 __qdisc_drop(skb, to_free);
632 return NET_XMIT_CN;
633}
634
635static struct sk_buff *noop_dequeue(struct Qdisc *qdisc)
636{
637 return NULL;
638}
639
640struct Qdisc_ops noop_qdisc_ops __read_mostly = {
641 .id = "noop",
642 .priv_size = 0,
643 .enqueue = noop_enqueue,
644 .dequeue = noop_dequeue,
645 .peek = noop_dequeue,
646 .owner = THIS_MODULE,
647};
648
649static struct netdev_queue noop_netdev_queue = {
650 RCU_POINTER_INITIALIZER(qdisc, &noop_qdisc),
651 .qdisc_sleeping = &noop_qdisc,
652};
653
654struct Qdisc noop_qdisc = {
655 .enqueue = noop_enqueue,
656 .dequeue = noop_dequeue,
657 .flags = TCQ_F_BUILTIN,
658 .ops = &noop_qdisc_ops,
659 .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
660 .dev_queue = &noop_netdev_queue,
661 .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
662 .gso_skb = {
663 .next = (struct sk_buff *)&noop_qdisc.gso_skb,
664 .prev = (struct sk_buff *)&noop_qdisc.gso_skb,
665 .qlen = 0,
666 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.gso_skb.lock),
667 },
668 .skb_bad_txq = {
669 .next = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
670 .prev = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
671 .qlen = 0,
672 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.skb_bad_txq.lock),
673 },
674};
675EXPORT_SYMBOL(noop_qdisc);
676
677static int noqueue_init(struct Qdisc *qdisc, struct nlattr *opt,
678 struct netlink_ext_ack *extack)
679{
680 /* register_qdisc() assigns a default of noop_enqueue if unset,
681 * but __dev_queue_xmit() treats noqueue only as such
682 * if this is NULL - so clear it here. */
683 qdisc->enqueue = NULL;
684 return 0;
685}
686
687struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
688 .id = "noqueue",
689 .priv_size = 0,
690 .init = noqueue_init,
691 .enqueue = noop_enqueue,
692 .dequeue = noop_dequeue,
693 .peek = noop_dequeue,
694 .owner = THIS_MODULE,
695};
696
697static const u8 prio2band[TC_PRIO_MAX + 1] = {
698 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1
699};
700
701/* 3-band FIFO queue: old style, but should be a bit faster than
702 generic prio+fifo combination.
703 */
704
705#define PFIFO_FAST_BANDS 3
706
707/*
708 * Private data for a pfifo_fast scheduler containing:
709 * - rings for priority bands
710 */
711struct pfifo_fast_priv {
712 struct skb_array q[PFIFO_FAST_BANDS];
713};
714
715static inline struct skb_array *band2list(struct pfifo_fast_priv *priv,
716 int band)
717{
718 return &priv->q[band];
719}
720
721static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
722 struct sk_buff **to_free)
723{
724 int band = prio2band[skb->priority & TC_PRIO_MAX];
725 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
726 struct skb_array *q = band2list(priv, band);
727 unsigned int pkt_len = qdisc_pkt_len(skb);
728 int err;
729
730 err = skb_array_produce(q, skb);
731
732 if (unlikely(err)) {
733 if (qdisc_is_percpu_stats(qdisc))
734 return qdisc_drop_cpu(skb, qdisc, to_free);
735 else
736 return qdisc_drop(skb, qdisc, to_free);
737 }
738
739 qdisc_update_stats_at_enqueue(qdisc, pkt_len);
740 return NET_XMIT_SUCCESS;
741}
742
743static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
744{
745 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
746 struct sk_buff *skb = NULL;
747 bool need_retry = true;
748 int band;
749
750retry:
751 for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
752 struct skb_array *q = band2list(priv, band);
753
754 if (__skb_array_empty(q))
755 continue;
756
757 skb = __skb_array_consume(q);
758 }
759 if (likely(skb)) {
760 qdisc_update_stats_at_dequeue(qdisc, skb);
761 } else if (need_retry &&
762 READ_ONCE(qdisc->state) & QDISC_STATE_NON_EMPTY) {
763 /* Delay clearing the STATE_MISSED here to reduce
764 * the overhead of the second spin_trylock() in
765 * qdisc_run_begin() and __netif_schedule() calling
766 * in qdisc_run_end().
767 */
768 clear_bit(__QDISC_STATE_MISSED, &qdisc->state);
769 clear_bit(__QDISC_STATE_DRAINING, &qdisc->state);
770
771 /* Make sure dequeuing happens after clearing
772 * STATE_MISSED.
773 */
774 smp_mb__after_atomic();
775
776 need_retry = false;
777
778 goto retry;
779 }
780
781 return skb;
782}
783
784static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
785{
786 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
787 struct sk_buff *skb = NULL;
788 int band;
789
790 for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
791 struct skb_array *q = band2list(priv, band);
792
793 skb = __skb_array_peek(q);
794 }
795
796 return skb;
797}
798
799static void pfifo_fast_reset(struct Qdisc *qdisc)
800{
801 int i, band;
802 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
803
804 for (band = 0; band < PFIFO_FAST_BANDS; band++) {
805 struct skb_array *q = band2list(priv, band);
806 struct sk_buff *skb;
807
808 /* NULL ring is possible if destroy path is due to a failed
809 * skb_array_init() in pfifo_fast_init() case.
810 */
811 if (!q->ring.queue)
812 continue;
813
814 while ((skb = __skb_array_consume(q)) != NULL)
815 kfree_skb(skb);
816 }
817
818 if (qdisc_is_percpu_stats(qdisc)) {
819 for_each_possible_cpu(i) {
820 struct gnet_stats_queue *q;
821
822 q = per_cpu_ptr(qdisc->cpu_qstats, i);
823 q->backlog = 0;
824 q->qlen = 0;
825 }
826 }
827}
828
829static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
830{
831 struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
832
833 memcpy(&opt.priomap, prio2band, TC_PRIO_MAX + 1);
834 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
835 goto nla_put_failure;
836 return skb->len;
837
838nla_put_failure:
839 return -1;
840}
841
842static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt,
843 struct netlink_ext_ack *extack)
844{
845 unsigned int qlen = qdisc_dev(qdisc)->tx_queue_len;
846 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
847 int prio;
848
849 /* guard against zero length rings */
850 if (!qlen)
851 return -EINVAL;
852
853 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
854 struct skb_array *q = band2list(priv, prio);
855 int err;
856
857 err = skb_array_init(q, qlen, GFP_KERNEL);
858 if (err)
859 return -ENOMEM;
860 }
861
862 /* Can by-pass the queue discipline */
863 qdisc->flags |= TCQ_F_CAN_BYPASS;
864 return 0;
865}
866
867static void pfifo_fast_destroy(struct Qdisc *sch)
868{
869 struct pfifo_fast_priv *priv = qdisc_priv(sch);
870 int prio;
871
872 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
873 struct skb_array *q = band2list(priv, prio);
874
875 /* NULL ring is possible if destroy path is due to a failed
876 * skb_array_init() in pfifo_fast_init() case.
877 */
878 if (!q->ring.queue)
879 continue;
880 /* Destroy ring but no need to kfree_skb because a call to
881 * pfifo_fast_reset() has already done that work.
882 */
883 ptr_ring_cleanup(&q->ring, NULL);
884 }
885}
886
887static int pfifo_fast_change_tx_queue_len(struct Qdisc *sch,
888 unsigned int new_len)
889{
890 struct pfifo_fast_priv *priv = qdisc_priv(sch);
891 struct skb_array *bands[PFIFO_FAST_BANDS];
892 int prio;
893
894 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
895 struct skb_array *q = band2list(priv, prio);
896
897 bands[prio] = q;
898 }
899
900 return skb_array_resize_multiple(bands, PFIFO_FAST_BANDS, new_len,
901 GFP_KERNEL);
902}
903
904struct Qdisc_ops pfifo_fast_ops __read_mostly = {
905 .id = "pfifo_fast",
906 .priv_size = sizeof(struct pfifo_fast_priv),
907 .enqueue = pfifo_fast_enqueue,
908 .dequeue = pfifo_fast_dequeue,
909 .peek = pfifo_fast_peek,
910 .init = pfifo_fast_init,
911 .destroy = pfifo_fast_destroy,
912 .reset = pfifo_fast_reset,
913 .dump = pfifo_fast_dump,
914 .change_tx_queue_len = pfifo_fast_change_tx_queue_len,
915 .owner = THIS_MODULE,
916 .static_flags = TCQ_F_NOLOCK | TCQ_F_CPUSTATS,
917};
918EXPORT_SYMBOL(pfifo_fast_ops);
919
920static struct lock_class_key qdisc_tx_busylock;
921
922struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
923 const struct Qdisc_ops *ops,
924 struct netlink_ext_ack *extack)
925{
926 struct Qdisc *sch;
927 unsigned int size = sizeof(*sch) + ops->priv_size;
928 int err = -ENOBUFS;
929 struct net_device *dev;
930
931 if (!dev_queue) {
932 NL_SET_ERR_MSG(extack, "No device queue given");
933 err = -EINVAL;
934 goto errout;
935 }
936
937 dev = dev_queue->dev;
938 sch = kzalloc_node(size, GFP_KERNEL, netdev_queue_numa_node_read(dev_queue));
939
940 if (!sch)
941 goto errout;
942 __skb_queue_head_init(&sch->gso_skb);
943 __skb_queue_head_init(&sch->skb_bad_txq);
944 gnet_stats_basic_sync_init(&sch->bstats);
945 spin_lock_init(&sch->q.lock);
946
947 if (ops->static_flags & TCQ_F_CPUSTATS) {
948 sch->cpu_bstats =
949 netdev_alloc_pcpu_stats(struct gnet_stats_basic_sync);
950 if (!sch->cpu_bstats)
951 goto errout1;
952
953 sch->cpu_qstats = alloc_percpu(struct gnet_stats_queue);
954 if (!sch->cpu_qstats) {
955 free_percpu(sch->cpu_bstats);
956 goto errout1;
957 }
958 }
959
960 spin_lock_init(&sch->busylock);
961 lockdep_set_class(&sch->busylock,
962 dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
963
964 /* seqlock has the same scope of busylock, for NOLOCK qdisc */
965 spin_lock_init(&sch->seqlock);
966 lockdep_set_class(&sch->seqlock,
967 dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
968
969 sch->ops = ops;
970 sch->flags = ops->static_flags;
971 sch->enqueue = ops->enqueue;
972 sch->dequeue = ops->dequeue;
973 sch->dev_queue = dev_queue;
974 netdev_hold(dev, &sch->dev_tracker, GFP_KERNEL);
975 refcount_set(&sch->refcnt, 1);
976
977 return sch;
978errout1:
979 kfree(sch);
980errout:
981 return ERR_PTR(err);
982}
983
984struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
985 const struct Qdisc_ops *ops,
986 unsigned int parentid,
987 struct netlink_ext_ack *extack)
988{
989 struct Qdisc *sch;
990
991 if (!try_module_get(ops->owner)) {
992 NL_SET_ERR_MSG(extack, "Failed to increase module reference counter");
993 return NULL;
994 }
995
996 sch = qdisc_alloc(dev_queue, ops, extack);
997 if (IS_ERR(sch)) {
998 module_put(ops->owner);
999 return NULL;
1000 }
1001 sch->parent = parentid;
1002
1003 if (!ops->init || ops->init(sch, NULL, extack) == 0) {
1004 trace_qdisc_create(ops, dev_queue->dev, parentid);
1005 return sch;
1006 }
1007
1008 qdisc_put(sch);
1009 return NULL;
1010}
1011EXPORT_SYMBOL(qdisc_create_dflt);
1012
1013/* Under qdisc_lock(qdisc) and BH! */
1014
1015void qdisc_reset(struct Qdisc *qdisc)
1016{
1017 const struct Qdisc_ops *ops = qdisc->ops;
1018
1019 trace_qdisc_reset(qdisc);
1020
1021 if (ops->reset)
1022 ops->reset(qdisc);
1023
1024 __skb_queue_purge(&qdisc->gso_skb);
1025 __skb_queue_purge(&qdisc->skb_bad_txq);
1026
1027 qdisc->q.qlen = 0;
1028 qdisc->qstats.backlog = 0;
1029}
1030EXPORT_SYMBOL(qdisc_reset);
1031
1032void qdisc_free(struct Qdisc *qdisc)
1033{
1034 if (qdisc_is_percpu_stats(qdisc)) {
1035 free_percpu(qdisc->cpu_bstats);
1036 free_percpu(qdisc->cpu_qstats);
1037 }
1038
1039 kfree(qdisc);
1040}
1041
1042static void qdisc_free_cb(struct rcu_head *head)
1043{
1044 struct Qdisc *q = container_of(head, struct Qdisc, rcu);
1045
1046 qdisc_free(q);
1047}
1048
1049static void qdisc_destroy(struct Qdisc *qdisc)
1050{
1051 const struct Qdisc_ops *ops = qdisc->ops;
1052
1053#ifdef CONFIG_NET_SCHED
1054 qdisc_hash_del(qdisc);
1055
1056 qdisc_put_stab(rtnl_dereference(qdisc->stab));
1057#endif
1058 gen_kill_estimator(&qdisc->rate_est);
1059
1060 qdisc_reset(qdisc);
1061
1062 if (ops->destroy)
1063 ops->destroy(qdisc);
1064
1065 module_put(ops->owner);
1066 netdev_put(qdisc_dev(qdisc), &qdisc->dev_tracker);
1067
1068 trace_qdisc_destroy(qdisc);
1069
1070 call_rcu(&qdisc->rcu, qdisc_free_cb);
1071}
1072
1073void qdisc_put(struct Qdisc *qdisc)
1074{
1075 if (!qdisc)
1076 return;
1077
1078 if (qdisc->flags & TCQ_F_BUILTIN ||
1079 !refcount_dec_and_test(&qdisc->refcnt))
1080 return;
1081
1082 qdisc_destroy(qdisc);
1083}
1084EXPORT_SYMBOL(qdisc_put);
1085
1086/* Version of qdisc_put() that is called with rtnl mutex unlocked.
1087 * Intended to be used as optimization, this function only takes rtnl lock if
1088 * qdisc reference counter reached zero.
1089 */
1090
1091void qdisc_put_unlocked(struct Qdisc *qdisc)
1092{
1093 if (qdisc->flags & TCQ_F_BUILTIN ||
1094 !refcount_dec_and_rtnl_lock(&qdisc->refcnt))
1095 return;
1096
1097 qdisc_destroy(qdisc);
1098 rtnl_unlock();
1099}
1100EXPORT_SYMBOL(qdisc_put_unlocked);
1101
1102/* Attach toplevel qdisc to device queue. */
1103struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
1104 struct Qdisc *qdisc)
1105{
1106 struct Qdisc *oqdisc = dev_queue->qdisc_sleeping;
1107 spinlock_t *root_lock;
1108
1109 root_lock = qdisc_lock(oqdisc);
1110 spin_lock_bh(root_lock);
1111
1112 /* ... and graft new one */
1113 if (qdisc == NULL)
1114 qdisc = &noop_qdisc;
1115 dev_queue->qdisc_sleeping = qdisc;
1116 rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
1117
1118 spin_unlock_bh(root_lock);
1119
1120 return oqdisc;
1121}
1122EXPORT_SYMBOL(dev_graft_qdisc);
1123
1124static void shutdown_scheduler_queue(struct net_device *dev,
1125 struct netdev_queue *dev_queue,
1126 void *_qdisc_default)
1127{
1128 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1129 struct Qdisc *qdisc_default = _qdisc_default;
1130
1131 if (qdisc) {
1132 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1133 dev_queue->qdisc_sleeping = qdisc_default;
1134
1135 qdisc_put(qdisc);
1136 }
1137}
1138
1139static void attach_one_default_qdisc(struct net_device *dev,
1140 struct netdev_queue *dev_queue,
1141 void *_unused)
1142{
1143 struct Qdisc *qdisc;
1144 const struct Qdisc_ops *ops = default_qdisc_ops;
1145
1146 if (dev->priv_flags & IFF_NO_QUEUE)
1147 ops = &noqueue_qdisc_ops;
1148 else if(dev->type == ARPHRD_CAN)
1149 ops = &pfifo_fast_ops;
1150
1151 qdisc = qdisc_create_dflt(dev_queue, ops, TC_H_ROOT, NULL);
1152 if (!qdisc)
1153 return;
1154
1155 if (!netif_is_multiqueue(dev))
1156 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
1157 dev_queue->qdisc_sleeping = qdisc;
1158}
1159
1160static void attach_default_qdiscs(struct net_device *dev)
1161{
1162 struct netdev_queue *txq;
1163 struct Qdisc *qdisc;
1164
1165 txq = netdev_get_tx_queue(dev, 0);
1166
1167 if (!netif_is_multiqueue(dev) ||
1168 dev->priv_flags & IFF_NO_QUEUE) {
1169 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
1170 qdisc = txq->qdisc_sleeping;
1171 rcu_assign_pointer(dev->qdisc, qdisc);
1172 qdisc_refcount_inc(qdisc);
1173 } else {
1174 qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT, NULL);
1175 if (qdisc) {
1176 rcu_assign_pointer(dev->qdisc, qdisc);
1177 qdisc->ops->attach(qdisc);
1178 }
1179 }
1180 qdisc = rtnl_dereference(dev->qdisc);
1181
1182 /* Detect default qdisc setup/init failed and fallback to "noqueue" */
1183 if (qdisc == &noop_qdisc) {
1184 netdev_warn(dev, "default qdisc (%s) fail, fallback to %s\n",
1185 default_qdisc_ops->id, noqueue_qdisc_ops.id);
1186 netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
1187 dev->priv_flags |= IFF_NO_QUEUE;
1188 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
1189 qdisc = txq->qdisc_sleeping;
1190 rcu_assign_pointer(dev->qdisc, qdisc);
1191 qdisc_refcount_inc(qdisc);
1192 dev->priv_flags ^= IFF_NO_QUEUE;
1193 }
1194
1195#ifdef CONFIG_NET_SCHED
1196 if (qdisc != &noop_qdisc)
1197 qdisc_hash_add(qdisc, false);
1198#endif
1199}
1200
1201static void transition_one_qdisc(struct net_device *dev,
1202 struct netdev_queue *dev_queue,
1203 void *_need_watchdog)
1204{
1205 struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
1206 int *need_watchdog_p = _need_watchdog;
1207
1208 if (!(new_qdisc->flags & TCQ_F_BUILTIN))
1209 clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
1210
1211 rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
1212 if (need_watchdog_p) {
1213 WRITE_ONCE(dev_queue->trans_start, 0);
1214 *need_watchdog_p = 1;
1215 }
1216}
1217
1218void dev_activate(struct net_device *dev)
1219{
1220 int need_watchdog;
1221
1222 /* No queueing discipline is attached to device;
1223 * create default one for devices, which need queueing
1224 * and noqueue_qdisc for virtual interfaces
1225 */
1226
1227 if (rtnl_dereference(dev->qdisc) == &noop_qdisc)
1228 attach_default_qdiscs(dev);
1229
1230 if (!netif_carrier_ok(dev))
1231 /* Delay activation until next carrier-on event */
1232 return;
1233
1234 need_watchdog = 0;
1235 netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
1236 if (dev_ingress_queue(dev))
1237 transition_one_qdisc(dev, dev_ingress_queue(dev), NULL);
1238
1239 if (need_watchdog) {
1240 netif_trans_update(dev);
1241 dev_watchdog_up(dev);
1242 }
1243}
1244EXPORT_SYMBOL(dev_activate);
1245
1246static void qdisc_deactivate(struct Qdisc *qdisc)
1247{
1248 if (qdisc->flags & TCQ_F_BUILTIN)
1249 return;
1250
1251 set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
1252}
1253
1254static void dev_deactivate_queue(struct net_device *dev,
1255 struct netdev_queue *dev_queue,
1256 void *_qdisc_default)
1257{
1258 struct Qdisc *qdisc_default = _qdisc_default;
1259 struct Qdisc *qdisc;
1260
1261 qdisc = rtnl_dereference(dev_queue->qdisc);
1262 if (qdisc) {
1263 qdisc_deactivate(qdisc);
1264 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1265 }
1266}
1267
1268static void dev_reset_queue(struct net_device *dev,
1269 struct netdev_queue *dev_queue,
1270 void *_unused)
1271{
1272 struct Qdisc *qdisc;
1273 bool nolock;
1274
1275 qdisc = dev_queue->qdisc_sleeping;
1276 if (!qdisc)
1277 return;
1278
1279 nolock = qdisc->flags & TCQ_F_NOLOCK;
1280
1281 if (nolock)
1282 spin_lock_bh(&qdisc->seqlock);
1283 spin_lock_bh(qdisc_lock(qdisc));
1284
1285 qdisc_reset(qdisc);
1286
1287 spin_unlock_bh(qdisc_lock(qdisc));
1288 if (nolock) {
1289 clear_bit(__QDISC_STATE_MISSED, &qdisc->state);
1290 clear_bit(__QDISC_STATE_DRAINING, &qdisc->state);
1291 spin_unlock_bh(&qdisc->seqlock);
1292 }
1293}
1294
1295static bool some_qdisc_is_busy(struct net_device *dev)
1296{
1297 unsigned int i;
1298
1299 for (i = 0; i < dev->num_tx_queues; i++) {
1300 struct netdev_queue *dev_queue;
1301 spinlock_t *root_lock;
1302 struct Qdisc *q;
1303 int val;
1304
1305 dev_queue = netdev_get_tx_queue(dev, i);
1306 q = dev_queue->qdisc_sleeping;
1307
1308 root_lock = qdisc_lock(q);
1309 spin_lock_bh(root_lock);
1310
1311 val = (qdisc_is_running(q) ||
1312 test_bit(__QDISC_STATE_SCHED, &q->state));
1313
1314 spin_unlock_bh(root_lock);
1315
1316 if (val)
1317 return true;
1318 }
1319 return false;
1320}
1321
1322/**
1323 * dev_deactivate_many - deactivate transmissions on several devices
1324 * @head: list of devices to deactivate
1325 *
1326 * This function returns only when all outstanding transmissions
1327 * have completed, unless all devices are in dismantle phase.
1328 */
1329void dev_deactivate_many(struct list_head *head)
1330{
1331 struct net_device *dev;
1332
1333 list_for_each_entry(dev, head, close_list) {
1334 netdev_for_each_tx_queue(dev, dev_deactivate_queue,
1335 &noop_qdisc);
1336 if (dev_ingress_queue(dev))
1337 dev_deactivate_queue(dev, dev_ingress_queue(dev),
1338 &noop_qdisc);
1339
1340 dev_watchdog_down(dev);
1341 }
1342
1343 /* Wait for outstanding qdisc-less dev_queue_xmit calls or
1344 * outstanding qdisc enqueuing calls.
1345 * This is avoided if all devices are in dismantle phase :
1346 * Caller will call synchronize_net() for us
1347 */
1348 synchronize_net();
1349
1350 list_for_each_entry(dev, head, close_list) {
1351 netdev_for_each_tx_queue(dev, dev_reset_queue, NULL);
1352
1353 if (dev_ingress_queue(dev))
1354 dev_reset_queue(dev, dev_ingress_queue(dev), NULL);
1355 }
1356
1357 /* Wait for outstanding qdisc_run calls. */
1358 list_for_each_entry(dev, head, close_list) {
1359 while (some_qdisc_is_busy(dev)) {
1360 /* wait_event() would avoid this sleep-loop but would
1361 * require expensive checks in the fast paths of packet
1362 * processing which isn't worth it.
1363 */
1364 schedule_timeout_uninterruptible(1);
1365 }
1366 }
1367}
1368
1369void dev_deactivate(struct net_device *dev)
1370{
1371 LIST_HEAD(single);
1372
1373 list_add(&dev->close_list, &single);
1374 dev_deactivate_many(&single);
1375 list_del(&single);
1376}
1377EXPORT_SYMBOL(dev_deactivate);
1378
1379static int qdisc_change_tx_queue_len(struct net_device *dev,
1380 struct netdev_queue *dev_queue)
1381{
1382 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1383 const struct Qdisc_ops *ops = qdisc->ops;
1384
1385 if (ops->change_tx_queue_len)
1386 return ops->change_tx_queue_len(qdisc, dev->tx_queue_len);
1387 return 0;
1388}
1389
1390void dev_qdisc_change_real_num_tx(struct net_device *dev,
1391 unsigned int new_real_tx)
1392{
1393 struct Qdisc *qdisc = rtnl_dereference(dev->qdisc);
1394
1395 if (qdisc->ops->change_real_num_tx)
1396 qdisc->ops->change_real_num_tx(qdisc, new_real_tx);
1397}
1398
1399void mq_change_real_num_tx(struct Qdisc *sch, unsigned int new_real_tx)
1400{
1401#ifdef CONFIG_NET_SCHED
1402 struct net_device *dev = qdisc_dev(sch);
1403 struct Qdisc *qdisc;
1404 unsigned int i;
1405
1406 for (i = new_real_tx; i < dev->real_num_tx_queues; i++) {
1407 qdisc = netdev_get_tx_queue(dev, i)->qdisc_sleeping;
1408 /* Only update the default qdiscs we created,
1409 * qdiscs with handles are always hashed.
1410 */
1411 if (qdisc != &noop_qdisc && !qdisc->handle)
1412 qdisc_hash_del(qdisc);
1413 }
1414 for (i = dev->real_num_tx_queues; i < new_real_tx; i++) {
1415 qdisc = netdev_get_tx_queue(dev, i)->qdisc_sleeping;
1416 if (qdisc != &noop_qdisc && !qdisc->handle)
1417 qdisc_hash_add(qdisc, false);
1418 }
1419#endif
1420}
1421EXPORT_SYMBOL(mq_change_real_num_tx);
1422
1423int dev_qdisc_change_tx_queue_len(struct net_device *dev)
1424{
1425 bool up = dev->flags & IFF_UP;
1426 unsigned int i;
1427 int ret = 0;
1428
1429 if (up)
1430 dev_deactivate(dev);
1431
1432 for (i = 0; i < dev->num_tx_queues; i++) {
1433 ret = qdisc_change_tx_queue_len(dev, &dev->_tx[i]);
1434
1435 /* TODO: revert changes on a partial failure */
1436 if (ret)
1437 break;
1438 }
1439
1440 if (up)
1441 dev_activate(dev);
1442 return ret;
1443}
1444
1445static void dev_init_scheduler_queue(struct net_device *dev,
1446 struct netdev_queue *dev_queue,
1447 void *_qdisc)
1448{
1449 struct Qdisc *qdisc = _qdisc;
1450
1451 rcu_assign_pointer(dev_queue->qdisc, qdisc);
1452 dev_queue->qdisc_sleeping = qdisc;
1453}
1454
1455void dev_init_scheduler(struct net_device *dev)
1456{
1457 rcu_assign_pointer(dev->qdisc, &noop_qdisc);
1458 netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
1459 if (dev_ingress_queue(dev))
1460 dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1461
1462 timer_setup(&dev->watchdog_timer, dev_watchdog, 0);
1463}
1464
1465void dev_shutdown(struct net_device *dev)
1466{
1467 netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
1468 if (dev_ingress_queue(dev))
1469 shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1470 qdisc_put(rtnl_dereference(dev->qdisc));
1471 rcu_assign_pointer(dev->qdisc, &noop_qdisc);
1472
1473 WARN_ON(timer_pending(&dev->watchdog_timer));
1474}
1475
1476/**
1477 * psched_ratecfg_precompute__() - Pre-compute values for reciprocal division
1478 * @rate: Rate to compute reciprocal division values of
1479 * @mult: Multiplier for reciprocal division
1480 * @shift: Shift for reciprocal division
1481 *
1482 * The multiplier and shift for reciprocal division by rate are stored
1483 * in mult and shift.
1484 *
1485 * The deal here is to replace a divide by a reciprocal one
1486 * in fast path (a reciprocal divide is a multiply and a shift)
1487 *
1488 * Normal formula would be :
1489 * time_in_ns = (NSEC_PER_SEC * len) / rate_bps
1490 *
1491 * We compute mult/shift to use instead :
1492 * time_in_ns = (len * mult) >> shift;
1493 *
1494 * We try to get the highest possible mult value for accuracy,
1495 * but have to make sure no overflows will ever happen.
1496 *
1497 * reciprocal_value() is not used here it doesn't handle 64-bit values.
1498 */
1499static void psched_ratecfg_precompute__(u64 rate, u32 *mult, u8 *shift)
1500{
1501 u64 factor = NSEC_PER_SEC;
1502
1503 *mult = 1;
1504 *shift = 0;
1505
1506 if (rate <= 0)
1507 return;
1508
1509 for (;;) {
1510 *mult = div64_u64(factor, rate);
1511 if (*mult & (1U << 31) || factor & (1ULL << 63))
1512 break;
1513 factor <<= 1;
1514 (*shift)++;
1515 }
1516}
1517
1518void psched_ratecfg_precompute(struct psched_ratecfg *r,
1519 const struct tc_ratespec *conf,
1520 u64 rate64)
1521{
1522 memset(r, 0, sizeof(*r));
1523 r->overhead = conf->overhead;
1524 r->mpu = conf->mpu;
1525 r->rate_bytes_ps = max_t(u64, conf->rate, rate64);
1526 r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK);
1527 psched_ratecfg_precompute__(r->rate_bytes_ps, &r->mult, &r->shift);
1528}
1529EXPORT_SYMBOL(psched_ratecfg_precompute);
1530
1531void psched_ppscfg_precompute(struct psched_pktrate *r, u64 pktrate64)
1532{
1533 r->rate_pkts_ps = pktrate64;
1534 psched_ratecfg_precompute__(r->rate_pkts_ps, &r->mult, &r->shift);
1535}
1536EXPORT_SYMBOL(psched_ppscfg_precompute);
1537
1538void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp,
1539 struct tcf_proto *tp_head)
1540{
1541 /* Protected with chain0->filter_chain_lock.
1542 * Can't access chain directly because tp_head can be NULL.
1543 */
1544 struct mini_Qdisc *miniq_old =
1545 rcu_dereference_protected(*miniqp->p_miniq, 1);
1546 struct mini_Qdisc *miniq;
1547
1548 if (!tp_head) {
1549 RCU_INIT_POINTER(*miniqp->p_miniq, NULL);
1550 } else {
1551 miniq = miniq_old != &miniqp->miniq1 ?
1552 &miniqp->miniq1 : &miniqp->miniq2;
1553
1554 /* We need to make sure that readers won't see the miniq
1555 * we are about to modify. So ensure that at least one RCU
1556 * grace period has elapsed since the miniq was made
1557 * inactive.
1558 */
1559 if (IS_ENABLED(CONFIG_PREEMPT_RT))
1560 cond_synchronize_rcu(miniq->rcu_state);
1561 else if (!poll_state_synchronize_rcu(miniq->rcu_state))
1562 synchronize_rcu_expedited();
1563
1564 miniq->filter_list = tp_head;
1565 rcu_assign_pointer(*miniqp->p_miniq, miniq);
1566 }
1567
1568 if (miniq_old)
1569 /* This is counterpart of the rcu sync above. We need to
1570 * block potential new user of miniq_old until all readers
1571 * are not seeing it.
1572 */
1573 miniq_old->rcu_state = start_poll_synchronize_rcu();
1574}
1575EXPORT_SYMBOL(mini_qdisc_pair_swap);
1576
1577void mini_qdisc_pair_block_init(struct mini_Qdisc_pair *miniqp,
1578 struct tcf_block *block)
1579{
1580 miniqp->miniq1.block = block;
1581 miniqp->miniq2.block = block;
1582}
1583EXPORT_SYMBOL(mini_qdisc_pair_block_init);
1584
1585void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc,
1586 struct mini_Qdisc __rcu **p_miniq)
1587{
1588 miniqp->miniq1.cpu_bstats = qdisc->cpu_bstats;
1589 miniqp->miniq1.cpu_qstats = qdisc->cpu_qstats;
1590 miniqp->miniq2.cpu_bstats = qdisc->cpu_bstats;
1591 miniqp->miniq2.cpu_qstats = qdisc->cpu_qstats;
1592 miniqp->miniq1.rcu_state = get_state_synchronize_rcu();
1593 miniqp->miniq2.rcu_state = miniqp->miniq1.rcu_state;
1594 miniqp->p_miniq = p_miniq;
1595}
1596EXPORT_SYMBOL(mini_qdisc_pair_init);