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 <net/hotdata.h>
31 #include <trace/events/qdisc.h>
32 #include <trace/events/net.h>
33 #include <net/xfrm.h>
34
35 /* Qdisc to use by default */
36 const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops;
37 EXPORT_SYMBOL(default_qdisc_ops);
38
39 static void qdisc_maybe_clear_missed(struct Qdisc *q,
40 const struct netdev_queue *txq)
41 {
42 clear_bit(__QDISC_STATE_MISSED, &q->state);
43
44 /* Make sure the below netif_xmit_frozen_or_stopped()
45 * checking happens after clearing STATE_MISSED.
46 */
47 smp_mb__after_atomic();
48
49 /* Checking netif_xmit_frozen_or_stopped() again to
50 * make sure STATE_MISSED is set if the STATE_MISSED
51 * set by netif_tx_wake_queue()'s rescheduling of
52 * net_tx_action() is cleared by the above clear_bit().
53 */
54 if (!netif_xmit_frozen_or_stopped(txq))
55 set_bit(__QDISC_STATE_MISSED, &q->state);
56 else
57 set_bit(__QDISC_STATE_DRAINING, &q->state);
58 }
59
60 /* Main transmission queue. */
61
62 /* Modifications to data participating in scheduling must be protected with
63 * qdisc_lock(qdisc) spinlock.
64 *
65 * The idea is the following:
66 * - enqueue, dequeue are serialized via qdisc root lock
67 * - ingress filtering is also serialized via qdisc root lock
68 * - updates to tree and tree walking are only done under the rtnl mutex.
69 */
70
71 #define SKB_XOFF_MAGIC ((struct sk_buff *)1UL)
72
73 static inline struct sk_buff *__skb_dequeue_bad_txq(struct Qdisc *q)
74 {
75 const struct netdev_queue *txq = q->dev_queue;
76 spinlock_t *lock = NULL;
77 struct sk_buff *skb;
78
79 if (q->flags & TCQ_F_NOLOCK) {
80 lock = qdisc_lock(q);
81 spin_lock(lock);
82 }
83
84 skb = skb_peek(&q->skb_bad_txq);
85 if (skb) {
86 /* check the reason of requeuing without tx lock first */
87 txq = skb_get_tx_queue(txq->dev, skb);
88 if (!netif_xmit_frozen_or_stopped(txq)) {
89 skb = __skb_dequeue(&q->skb_bad_txq);
90 if (qdisc_is_percpu_stats(q)) {
91 qdisc_qstats_cpu_backlog_dec(q, skb);
92 qdisc_qstats_cpu_qlen_dec(q);
93 } else {
94 qdisc_qstats_backlog_dec(q, skb);
95 q->q.qlen--;
96 }
97 } else {
98 skb = SKB_XOFF_MAGIC;
99 qdisc_maybe_clear_missed(q, txq);
100 }
101 }
102
103 if (lock)
104 spin_unlock(lock);
105
106 return skb;
107 }
108
109 static inline struct sk_buff *qdisc_dequeue_skb_bad_txq(struct Qdisc *q)
110 {
111 struct sk_buff *skb = skb_peek(&q->skb_bad_txq);
112
113 if (unlikely(skb))
114 skb = __skb_dequeue_bad_txq(q);
115
116 return skb;
117 }
118
119 static inline void qdisc_enqueue_skb_bad_txq(struct Qdisc *q,
120 struct sk_buff *skb)
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 __skb_queue_tail(&q->skb_bad_txq, skb);
130
131 if (qdisc_is_percpu_stats(q)) {
132 qdisc_qstats_cpu_backlog_inc(q, skb);
133 qdisc_qstats_cpu_qlen_inc(q);
134 } else {
135 qdisc_qstats_backlog_inc(q, skb);
136 q->q.qlen++;
137 }
138
139 if (lock)
140 spin_unlock(lock);
141 }
142
143 static inline void dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
144 {
145 spinlock_t *lock = NULL;
146
147 if (q->flags & TCQ_F_NOLOCK) {
148 lock = qdisc_lock(q);
149 spin_lock(lock);
150 }
151
152 while (skb) {
153 struct sk_buff *next = skb->next;
154
155 __skb_queue_tail(&q->gso_skb, skb);
156
157 /* it's still part of the queue */
158 if (qdisc_is_percpu_stats(q)) {
159 qdisc_qstats_cpu_requeues_inc(q);
160 qdisc_qstats_cpu_backlog_inc(q, skb);
161 qdisc_qstats_cpu_qlen_inc(q);
162 } else {
163 q->qstats.requeues++;
164 qdisc_qstats_backlog_inc(q, skb);
165 q->q.qlen++;
166 }
167
168 skb = next;
169 }
170
171 if (lock) {
172 spin_unlock(lock);
173 set_bit(__QDISC_STATE_MISSED, &q->state);
174 } else {
175 __netif_schedule(q);
176 }
177 }
178
179 static void try_bulk_dequeue_skb(struct Qdisc *q,
180 struct sk_buff *skb,
181 const struct netdev_queue *txq,
182 int *packets)
183 {
184 int bytelimit = qdisc_avail_bulklimit(txq) - skb->len;
185
186 while (bytelimit > 0) {
187 struct sk_buff *nskb = q->dequeue(q);
188
189 if (!nskb)
190 break;
191
192 bytelimit -= nskb->len; /* covers GSO len */
193 skb->next = nskb;
194 skb = nskb;
195 (*packets)++; /* GSO counts as one pkt */
196 }
197 skb_mark_not_on_list(skb);
198 }
199
200 /* This variant of try_bulk_dequeue_skb() makes sure
201 * all skbs in the chain are for the same txq
202 */
203 static void try_bulk_dequeue_skb_slow(struct Qdisc *q,
204 struct sk_buff *skb,
205 int *packets)
206 {
207 int mapping = skb_get_queue_mapping(skb);
208 struct sk_buff *nskb;
209 int cnt = 0;
210
211 do {
212 nskb = q->dequeue(q);
213 if (!nskb)
214 break;
215 if (unlikely(skb_get_queue_mapping(nskb) != mapping)) {
216 qdisc_enqueue_skb_bad_txq(q, nskb);
217 break;
218 }
219 skb->next = nskb;
220 skb = nskb;
221 } while (++cnt < 8);
222 (*packets) += cnt;
223 skb_mark_not_on_list(skb);
224 }
225
226 /* Note that dequeue_skb can possibly return a SKB list (via skb->next).
227 * A requeued skb (via q->gso_skb) can also be a SKB list.
228 */
229 static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
230 int *packets)
231 {
232 const struct netdev_queue *txq = q->dev_queue;
233 struct sk_buff *skb = NULL;
234
235 *packets = 1;
236 if (unlikely(!skb_queue_empty(&q->gso_skb))) {
237 spinlock_t *lock = NULL;
238
239 if (q->flags & TCQ_F_NOLOCK) {
240 lock = qdisc_lock(q);
241 spin_lock(lock);
242 }
243
244 skb = skb_peek(&q->gso_skb);
245
246 /* skb may be null if another cpu pulls gso_skb off in between
247 * empty check and lock.
248 */
249 if (!skb) {
250 if (lock)
251 spin_unlock(lock);
252 goto validate;
253 }
254
255 /* skb in gso_skb were already validated */
256 *validate = false;
257 if (xfrm_offload(skb))
258 *validate = true;
259 /* check the reason of requeuing without tx lock first */
260 txq = skb_get_tx_queue(txq->dev, skb);
261 if (!netif_xmit_frozen_or_stopped(txq)) {
262 skb = __skb_dequeue(&q->gso_skb);
263 if (qdisc_is_percpu_stats(q)) {
264 qdisc_qstats_cpu_backlog_dec(q, skb);
265 qdisc_qstats_cpu_qlen_dec(q);
266 } else {
267 qdisc_qstats_backlog_dec(q, skb);
268 q->q.qlen--;
269 }
270 } else {
271 skb = NULL;
272 qdisc_maybe_clear_missed(q, txq);
273 }
274 if (lock)
275 spin_unlock(lock);
276 goto trace;
277 }
278 validate:
279 *validate = true;
280
281 if ((q->flags & TCQ_F_ONETXQUEUE) &&
282 netif_xmit_frozen_or_stopped(txq)) {
283 qdisc_maybe_clear_missed(q, txq);
284 return skb;
285 }
286
287 skb = qdisc_dequeue_skb_bad_txq(q);
288 if (unlikely(skb)) {
289 if (skb == SKB_XOFF_MAGIC)
290 return NULL;
291 goto bulk;
292 }
293 skb = q->dequeue(q);
294 if (skb) {
295 bulk:
296 if (qdisc_may_bulk(q))
297 try_bulk_dequeue_skb(q, skb, txq, packets);
298 else
299 try_bulk_dequeue_skb_slow(q, skb, packets);
300 }
301 trace:
302 trace_qdisc_dequeue(q, txq, *packets, skb);
303 return skb;
304 }
305
306 /*
307 * Transmit possibly several skbs, and handle the return status as
308 * required. Owning qdisc running bit guarantees that only one CPU
309 * can execute this function.
310 *
311 * Returns to the caller:
312 * false - hardware queue frozen backoff
313 * true - feel free to send more pkts
314 */
315 bool sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
316 struct net_device *dev, struct netdev_queue *txq,
317 spinlock_t *root_lock, bool validate)
318 {
319 int ret = NETDEV_TX_BUSY;
320 bool again = false;
321
322 /* And release qdisc */
323 if (root_lock)
324 spin_unlock(root_lock);
325
326 /* Note that we validate skb (GSO, checksum, ...) outside of locks */
327 if (validate)
328 skb = validate_xmit_skb_list(skb, dev, &again);
329
330 #ifdef CONFIG_XFRM_OFFLOAD
331 if (unlikely(again)) {
332 if (root_lock)
333 spin_lock(root_lock);
334
335 dev_requeue_skb(skb, q);
336 return false;
337 }
338 #endif
339
340 if (likely(skb)) {
341 HARD_TX_LOCK(dev, txq, smp_processor_id());
342 if (!netif_xmit_frozen_or_stopped(txq))
343 skb = dev_hard_start_xmit(skb, dev, txq, &ret);
344 else
345 qdisc_maybe_clear_missed(q, txq);
346
347 HARD_TX_UNLOCK(dev, txq);
348 } else {
349 if (root_lock)
350 spin_lock(root_lock);
351 return true;
352 }
353
354 if (root_lock)
355 spin_lock(root_lock);
356
357 if (!dev_xmit_complete(ret)) {
358 /* Driver returned NETDEV_TX_BUSY - requeue skb */
359 if (unlikely(ret != NETDEV_TX_BUSY))
360 net_warn_ratelimited("BUG %s code %d qlen %d\n",
361 dev->name, ret, q->q.qlen);
362
363 dev_requeue_skb(skb, q);
364 return false;
365 }
366
367 return true;
368 }
369
370 /*
371 * NOTE: Called under qdisc_lock(q) with locally disabled BH.
372 *
373 * running seqcount guarantees only one CPU can process
374 * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
375 * this queue.
376 *
377 * netif_tx_lock serializes accesses to device driver.
378 *
379 * qdisc_lock(q) and netif_tx_lock are mutually exclusive,
380 * if one is grabbed, another must be free.
381 *
382 * Note, that this procedure can be called by a watchdog timer
383 *
384 * Returns to the caller:
385 * 0 - queue is empty or throttled.
386 * >0 - queue is not empty.
387 *
388 */
389 static inline bool qdisc_restart(struct Qdisc *q, int *packets)
390 {
391 spinlock_t *root_lock = NULL;
392 struct netdev_queue *txq;
393 struct net_device *dev;
394 struct sk_buff *skb;
395 bool validate;
396
397 /* Dequeue packet */
398 skb = dequeue_skb(q, &validate, packets);
399 if (unlikely(!skb))
400 return false;
401
402 if (!(q->flags & TCQ_F_NOLOCK))
403 root_lock = qdisc_lock(q);
404
405 dev = qdisc_dev(q);
406 txq = skb_get_tx_queue(dev, skb);
407
408 return sch_direct_xmit(skb, q, dev, txq, root_lock, validate);
409 }
410
411 void __qdisc_run(struct Qdisc *q)
412 {
413 int quota = READ_ONCE(net_hotdata.dev_tx_weight);
414 int packets;
415
416 while (qdisc_restart(q, &packets)) {
417 quota -= packets;
418 if (quota <= 0) {
419 if (q->flags & TCQ_F_NOLOCK)
420 set_bit(__QDISC_STATE_MISSED, &q->state);
421 else
422 __netif_schedule(q);
423
424 break;
425 }
426 }
427 }
428
429 unsigned long dev_trans_start(struct net_device *dev)
430 {
431 unsigned long res = READ_ONCE(netdev_get_tx_queue(dev, 0)->trans_start);
432 unsigned long val;
433 unsigned int i;
434
435 for (i = 1; i < dev->num_tx_queues; i++) {
436 val = READ_ONCE(netdev_get_tx_queue(dev, i)->trans_start);
437 if (val && time_after(val, res))
438 res = val;
439 }
440
441 return res;
442 }
443 EXPORT_SYMBOL(dev_trans_start);
444
445 static void netif_freeze_queues(struct net_device *dev)
446 {
447 unsigned int i;
448 int cpu;
449
450 cpu = smp_processor_id();
451 for (i = 0; i < dev->num_tx_queues; i++) {
452 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
453
454 /* We are the only thread of execution doing a
455 * freeze, but we have to grab the _xmit_lock in
456 * order to synchronize with threads which are in
457 * the ->hard_start_xmit() handler and already
458 * checked the frozen bit.
459 */
460 __netif_tx_lock(txq, cpu);
461 set_bit(__QUEUE_STATE_FROZEN, &txq->state);
462 __netif_tx_unlock(txq);
463 }
464 }
465
466 void netif_tx_lock(struct net_device *dev)
467 {
468 spin_lock(&dev->tx_global_lock);
469 netif_freeze_queues(dev);
470 }
471 EXPORT_SYMBOL(netif_tx_lock);
472
473 static void netif_unfreeze_queues(struct net_device *dev)
474 {
475 unsigned int i;
476
477 for (i = 0; i < dev->num_tx_queues; i++) {
478 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
479
480 /* No need to grab the _xmit_lock here. If the
481 * queue is not stopped for another reason, we
482 * force a schedule.
483 */
484 clear_bit(__QUEUE_STATE_FROZEN, &txq->state);
485 netif_schedule_queue(txq);
486 }
487 }
488
489 void netif_tx_unlock(struct net_device *dev)
490 {
491 netif_unfreeze_queues(dev);
492 spin_unlock(&dev->tx_global_lock);
493 }
494 EXPORT_SYMBOL(netif_tx_unlock);
495
496 static void dev_watchdog(struct timer_list *t)
497 {
498 struct net_device *dev = from_timer(dev, t, watchdog_timer);
499 bool release = true;
500
501 spin_lock(&dev->tx_global_lock);
502 if (!qdisc_tx_is_noop(dev)) {
503 if (netif_device_present(dev) &&
504 netif_running(dev) &&
505 netif_carrier_ok(dev)) {
506 unsigned int timedout_ms = 0;
507 unsigned int i;
508 unsigned long trans_start;
509 unsigned long oldest_start = jiffies;
510
511 for (i = 0; i < dev->num_tx_queues; i++) {
512 struct netdev_queue *txq;
513
514 txq = netdev_get_tx_queue(dev, i);
515 trans_start = READ_ONCE(txq->trans_start);
516 if (!netif_xmit_stopped(txq))
517 continue;
518 if (time_after(jiffies, trans_start + dev->watchdog_timeo)) {
519 timedout_ms = jiffies_to_msecs(jiffies - trans_start);
520 atomic_long_inc(&txq->trans_timeout);
521 break;
522 }
523 if (time_after(oldest_start, trans_start))
524 oldest_start = trans_start;
525 }
526
527 if (unlikely(timedout_ms)) {
528 trace_net_dev_xmit_timeout(dev, i);
529 netdev_crit(dev, "NETDEV WATCHDOG: CPU: %d: transmit queue %u timed out %u ms\n",
530 raw_smp_processor_id(),
531 i, timedout_ms);
532 netif_freeze_queues(dev);
533 dev->netdev_ops->ndo_tx_timeout(dev, i);
534 netif_unfreeze_queues(dev);
535 }
536 if (!mod_timer(&dev->watchdog_timer,
537 round_jiffies(oldest_start +
538 dev->watchdog_timeo)))
539 release = false;
540 }
541 }
542 spin_unlock(&dev->tx_global_lock);
543
544 if (release)
545 netdev_put(dev, &dev->watchdog_dev_tracker);
546 }
547
548 void __netdev_watchdog_up(struct net_device *dev)
549 {
550 if (dev->netdev_ops->ndo_tx_timeout) {
551 if (dev->watchdog_timeo <= 0)
552 dev->watchdog_timeo = 5*HZ;
553 if (!mod_timer(&dev->watchdog_timer,
554 round_jiffies(jiffies + dev->watchdog_timeo)))
555 netdev_hold(dev, &dev->watchdog_dev_tracker,
556 GFP_ATOMIC);
557 }
558 }
559 EXPORT_SYMBOL_GPL(__netdev_watchdog_up);
560
561 static void dev_watchdog_up(struct net_device *dev)
562 {
563 __netdev_watchdog_up(dev);
564 }
565
566 static void dev_watchdog_down(struct net_device *dev)
567 {
568 netif_tx_lock_bh(dev);
569 if (del_timer(&dev->watchdog_timer))
570 netdev_put(dev, &dev->watchdog_dev_tracker);
571 netif_tx_unlock_bh(dev);
572 }
573
574 /**
575 * netif_carrier_on - set carrier
576 * @dev: network device
577 *
578 * Device has detected acquisition of carrier.
579 */
580 void netif_carrier_on(struct net_device *dev)
581 {
582 if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
583 if (dev->reg_state == NETREG_UNINITIALIZED)
584 return;
585 atomic_inc(&dev->carrier_up_count);
586 linkwatch_fire_event(dev);
587 if (netif_running(dev))
588 __netdev_watchdog_up(dev);
589 }
590 }
591 EXPORT_SYMBOL(netif_carrier_on);
592
593 /**
594 * netif_carrier_off - clear carrier
595 * @dev: network device
596 *
597 * Device has detected loss of carrier.
598 */
599 void netif_carrier_off(struct net_device *dev)
600 {
601 if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
602 if (dev->reg_state == NETREG_UNINITIALIZED)
603 return;
604 atomic_inc(&dev->carrier_down_count);
605 linkwatch_fire_event(dev);
606 }
607 }
608 EXPORT_SYMBOL(netif_carrier_off);
609
610 /**
611 * netif_carrier_event - report carrier state event
612 * @dev: network device
613 *
614 * Device has detected a carrier event but the carrier state wasn't changed.
615 * Use in drivers when querying carrier state asynchronously, to avoid missing
616 * events (link flaps) if link recovers before it's queried.
617 */
618 void netif_carrier_event(struct net_device *dev)
619 {
620 if (dev->reg_state == NETREG_UNINITIALIZED)
621 return;
622 atomic_inc(&dev->carrier_up_count);
623 atomic_inc(&dev->carrier_down_count);
624 linkwatch_fire_event(dev);
625 }
626 EXPORT_SYMBOL_GPL(netif_carrier_event);
627
628 /* "NOOP" scheduler: the best scheduler, recommended for all interfaces
629 under all circumstances. It is difficult to invent anything faster or
630 cheaper.
631 */
632
633 static int noop_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
634 struct sk_buff **to_free)
635 {
636 dev_core_stats_tx_dropped_inc(skb->dev);
637 __qdisc_drop(skb, to_free);
638 return NET_XMIT_CN;
639 }
640
641 static struct sk_buff *noop_dequeue(struct Qdisc *qdisc)
642 {
643 return NULL;
644 }
645
646 struct Qdisc_ops noop_qdisc_ops __read_mostly = {
647 .id = "noop",
648 .priv_size = 0,
649 .enqueue = noop_enqueue,
650 .dequeue = noop_dequeue,
651 .peek = noop_dequeue,
652 .owner = THIS_MODULE,
653 };
654
655 static struct netdev_queue noop_netdev_queue = {
656 RCU_POINTER_INITIALIZER(qdisc, &noop_qdisc),
657 RCU_POINTER_INITIALIZER(qdisc_sleeping, &noop_qdisc),
658 };
659
660 struct Qdisc noop_qdisc = {
661 .enqueue = noop_enqueue,
662 .dequeue = noop_dequeue,
663 .flags = TCQ_F_BUILTIN,
664 .ops = &noop_qdisc_ops,
665 .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
666 .dev_queue = &noop_netdev_queue,
667 .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
668 .gso_skb = {
669 .next = (struct sk_buff *)&noop_qdisc.gso_skb,
670 .prev = (struct sk_buff *)&noop_qdisc.gso_skb,
671 .qlen = 0,
672 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.gso_skb.lock),
673 },
674 .skb_bad_txq = {
675 .next = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
676 .prev = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
677 .qlen = 0,
678 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.skb_bad_txq.lock),
679 },
680 .owner = -1,
681 };
682 EXPORT_SYMBOL(noop_qdisc);
683
684 static int noqueue_init(struct Qdisc *qdisc, struct nlattr *opt,
685 struct netlink_ext_ack *extack)
686 {
687 /* register_qdisc() assigns a default of noop_enqueue if unset,
688 * but __dev_queue_xmit() treats noqueue only as such
689 * if this is NULL - so clear it here. */
690 qdisc->enqueue = NULL;
691 return 0;
692 }
693
694 struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
695 .id = "noqueue",
696 .priv_size = 0,
697 .init = noqueue_init,
698 .enqueue = noop_enqueue,
699 .dequeue = noop_dequeue,
700 .peek = noop_dequeue,
701 .owner = THIS_MODULE,
702 };
703
704 const u8 sch_default_prio2band[TC_PRIO_MAX + 1] = {
705 1, 2, 2, 2, 1, 2, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1
706 };
707 EXPORT_SYMBOL(sch_default_prio2band);
708
709 /* 3-band FIFO queue: old style, but should be a bit faster than
710 generic prio+fifo combination.
711 */
712
713 #define PFIFO_FAST_BANDS 3
714
715 /*
716 * Private data for a pfifo_fast scheduler containing:
717 * - rings for priority bands
718 */
719 struct pfifo_fast_priv {
720 struct skb_array q[PFIFO_FAST_BANDS];
721 };
722
723 static inline struct skb_array *band2list(struct pfifo_fast_priv *priv,
724 int band)
725 {
726 return &priv->q[band];
727 }
728
729 static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
730 struct sk_buff **to_free)
731 {
732 int band = sch_default_prio2band[skb->priority & TC_PRIO_MAX];
733 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
734 struct skb_array *q = band2list(priv, band);
735 unsigned int pkt_len = qdisc_pkt_len(skb);
736 int err;
737
738 err = skb_array_produce(q, skb);
739
740 if (unlikely(err)) {
741 if (qdisc_is_percpu_stats(qdisc))
742 return qdisc_drop_cpu(skb, qdisc, to_free);
743 else
744 return qdisc_drop(skb, qdisc, to_free);
745 }
746
747 qdisc_update_stats_at_enqueue(qdisc, pkt_len);
748 return NET_XMIT_SUCCESS;
749 }
750
751 static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
752 {
753 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
754 struct sk_buff *skb = NULL;
755 bool need_retry = true;
756 int band;
757
758 retry:
759 for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
760 struct skb_array *q = band2list(priv, band);
761
762 if (__skb_array_empty(q))
763 continue;
764
765 skb = __skb_array_consume(q);
766 }
767 if (likely(skb)) {
768 qdisc_update_stats_at_dequeue(qdisc, skb);
769 } else if (need_retry &&
770 READ_ONCE(qdisc->state) & QDISC_STATE_NON_EMPTY) {
771 /* Delay clearing the STATE_MISSED here to reduce
772 * the overhead of the second spin_trylock() in
773 * qdisc_run_begin() and __netif_schedule() calling
774 * in qdisc_run_end().
775 */
776 clear_bit(__QDISC_STATE_MISSED, &qdisc->state);
777 clear_bit(__QDISC_STATE_DRAINING, &qdisc->state);
778
779 /* Make sure dequeuing happens after clearing
780 * STATE_MISSED.
781 */
782 smp_mb__after_atomic();
783
784 need_retry = false;
785
786 goto retry;
787 }
788
789 return skb;
790 }
791
792 static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
793 {
794 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
795 struct sk_buff *skb = NULL;
796 int band;
797
798 for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
799 struct skb_array *q = band2list(priv, band);
800
801 skb = __skb_array_peek(q);
802 }
803
804 return skb;
805 }
806
807 static void pfifo_fast_reset(struct Qdisc *qdisc)
808 {
809 int i, band;
810 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
811
812 for (band = 0; band < PFIFO_FAST_BANDS; band++) {
813 struct skb_array *q = band2list(priv, band);
814 struct sk_buff *skb;
815
816 /* NULL ring is possible if destroy path is due to a failed
817 * skb_array_init() in pfifo_fast_init() case.
818 */
819 if (!q->ring.queue)
820 continue;
821
822 while ((skb = __skb_array_consume(q)) != NULL)
823 kfree_skb(skb);
824 }
825
826 if (qdisc_is_percpu_stats(qdisc)) {
827 for_each_possible_cpu(i) {
828 struct gnet_stats_queue *q;
829
830 q = per_cpu_ptr(qdisc->cpu_qstats, i);
831 q->backlog = 0;
832 q->qlen = 0;
833 }
834 }
835 }
836
837 static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
838 {
839 struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
840
841 memcpy(&opt.priomap, sch_default_prio2band, TC_PRIO_MAX + 1);
842 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
843 goto nla_put_failure;
844 return skb->len;
845
846 nla_put_failure:
847 return -1;
848 }
849
850 static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt,
851 struct netlink_ext_ack *extack)
852 {
853 unsigned int qlen = qdisc_dev(qdisc)->tx_queue_len;
854 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
855 int prio;
856
857 /* guard against zero length rings */
858 if (!qlen)
859 return -EINVAL;
860
861 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
862 struct skb_array *q = band2list(priv, prio);
863 int err;
864
865 err = skb_array_init(q, qlen, GFP_KERNEL);
866 if (err)
867 return -ENOMEM;
868 }
869
870 /* Can by-pass the queue discipline */
871 qdisc->flags |= TCQ_F_CAN_BYPASS;
872 return 0;
873 }
874
875 static void pfifo_fast_destroy(struct Qdisc *sch)
876 {
877 struct pfifo_fast_priv *priv = qdisc_priv(sch);
878 int prio;
879
880 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
881 struct skb_array *q = band2list(priv, prio);
882
883 /* NULL ring is possible if destroy path is due to a failed
884 * skb_array_init() in pfifo_fast_init() case.
885 */
886 if (!q->ring.queue)
887 continue;
888 /* Destroy ring but no need to kfree_skb because a call to
889 * pfifo_fast_reset() has already done that work.
890 */
891 ptr_ring_cleanup(&q->ring, NULL);
892 }
893 }
894
895 static int pfifo_fast_change_tx_queue_len(struct Qdisc *sch,
896 unsigned int new_len)
897 {
898 struct pfifo_fast_priv *priv = qdisc_priv(sch);
899 struct skb_array *bands[PFIFO_FAST_BANDS];
900 int prio;
901
902 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
903 struct skb_array *q = band2list(priv, prio);
904
905 bands[prio] = q;
906 }
907
908 return skb_array_resize_multiple(bands, PFIFO_FAST_BANDS, new_len,
909 GFP_KERNEL);
910 }
911
912 struct Qdisc_ops pfifo_fast_ops __read_mostly = {
913 .id = "pfifo_fast",
914 .priv_size = sizeof(struct pfifo_fast_priv),
915 .enqueue = pfifo_fast_enqueue,
916 .dequeue = pfifo_fast_dequeue,
917 .peek = pfifo_fast_peek,
918 .init = pfifo_fast_init,
919 .destroy = pfifo_fast_destroy,
920 .reset = pfifo_fast_reset,
921 .dump = pfifo_fast_dump,
922 .change_tx_queue_len = pfifo_fast_change_tx_queue_len,
923 .owner = THIS_MODULE,
924 .static_flags = TCQ_F_NOLOCK | TCQ_F_CPUSTATS,
925 };
926 EXPORT_SYMBOL(pfifo_fast_ops);
927
928 static struct lock_class_key qdisc_tx_busylock;
929
930 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
931 const struct Qdisc_ops *ops,
932 struct netlink_ext_ack *extack)
933 {
934 struct Qdisc *sch;
935 unsigned int size = sizeof(*sch) + ops->priv_size;
936 int err = -ENOBUFS;
937 struct net_device *dev;
938
939 if (!dev_queue) {
940 NL_SET_ERR_MSG(extack, "No device queue given");
941 err = -EINVAL;
942 goto errout;
943 }
944
945 dev = dev_queue->dev;
946 sch = kzalloc_node(size, GFP_KERNEL, netdev_queue_numa_node_read(dev_queue));
947
948 if (!sch)
949 goto errout;
950 __skb_queue_head_init(&sch->gso_skb);
951 __skb_queue_head_init(&sch->skb_bad_txq);
952 gnet_stats_basic_sync_init(&sch->bstats);
953 lockdep_register_key(&sch->root_lock_key);
954 spin_lock_init(&sch->q.lock);
955 lockdep_set_class(&sch->q.lock, &sch->root_lock_key);
956
957 if (ops->static_flags & TCQ_F_CPUSTATS) {
958 sch->cpu_bstats =
959 netdev_alloc_pcpu_stats(struct gnet_stats_basic_sync);
960 if (!sch->cpu_bstats)
961 goto errout1;
962
963 sch->cpu_qstats = alloc_percpu(struct gnet_stats_queue);
964 if (!sch->cpu_qstats) {
965 free_percpu(sch->cpu_bstats);
966 goto errout1;
967 }
968 }
969
970 spin_lock_init(&sch->busylock);
971 lockdep_set_class(&sch->busylock,
972 dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
973
974 /* seqlock has the same scope of busylock, for NOLOCK qdisc */
975 spin_lock_init(&sch->seqlock);
976 lockdep_set_class(&sch->seqlock,
977 dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
978
979 sch->ops = ops;
980 sch->flags = ops->static_flags;
981 sch->enqueue = ops->enqueue;
982 sch->dequeue = ops->dequeue;
983 sch->dev_queue = dev_queue;
984 sch->owner = -1;
985 netdev_hold(dev, &sch->dev_tracker, GFP_KERNEL);
986 refcount_set(&sch->refcnt, 1);
987
988 return sch;
989 errout1:
990 lockdep_unregister_key(&sch->root_lock_key);
991 kfree(sch);
992 errout:
993 return ERR_PTR(err);
994 }
995
996 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
997 const struct Qdisc_ops *ops,
998 unsigned int parentid,
999 struct netlink_ext_ack *extack)
1000 {
1001 struct Qdisc *sch;
1002
1003 if (!try_module_get(ops->owner)) {
1004 NL_SET_ERR_MSG(extack, "Failed to increase module reference counter");
1005 return NULL;
1006 }
1007
1008 sch = qdisc_alloc(dev_queue, ops, extack);
1009 if (IS_ERR(sch)) {
1010 module_put(ops->owner);
1011 return NULL;
1012 }
1013 sch->parent = parentid;
1014
1015 if (!ops->init || ops->init(sch, NULL, extack) == 0) {
1016 trace_qdisc_create(ops, dev_queue->dev, parentid);
1017 return sch;
1018 }
1019
1020 qdisc_put(sch);
1021 return NULL;
1022 }
1023 EXPORT_SYMBOL(qdisc_create_dflt);
1024
1025 /* Under qdisc_lock(qdisc) and BH! */
1026
1027 void qdisc_reset(struct Qdisc *qdisc)
1028 {
1029 const struct Qdisc_ops *ops = qdisc->ops;
1030
1031 trace_qdisc_reset(qdisc);
1032
1033 if (ops->reset)
1034 ops->reset(qdisc);
1035
1036 __skb_queue_purge(&qdisc->gso_skb);
1037 __skb_queue_purge(&qdisc->skb_bad_txq);
1038
1039 qdisc->q.qlen = 0;
1040 qdisc->qstats.backlog = 0;
1041 }
1042 EXPORT_SYMBOL(qdisc_reset);
1043
1044 void qdisc_free(struct Qdisc *qdisc)
1045 {
1046 if (qdisc_is_percpu_stats(qdisc)) {
1047 free_percpu(qdisc->cpu_bstats);
1048 free_percpu(qdisc->cpu_qstats);
1049 }
1050
1051 kfree(qdisc);
1052 }
1053
1054 static void qdisc_free_cb(struct rcu_head *head)
1055 {
1056 struct Qdisc *q = container_of(head, struct Qdisc, rcu);
1057
1058 qdisc_free(q);
1059 }
1060
1061 static void __qdisc_destroy(struct Qdisc *qdisc)
1062 {
1063 const struct Qdisc_ops *ops = qdisc->ops;
1064 struct net_device *dev = qdisc_dev(qdisc);
1065
1066 #ifdef CONFIG_NET_SCHED
1067 qdisc_hash_del(qdisc);
1068
1069 qdisc_put_stab(rtnl_dereference(qdisc->stab));
1070 #endif
1071 gen_kill_estimator(&qdisc->rate_est);
1072
1073 qdisc_reset(qdisc);
1074
1075
1076 if (ops->destroy)
1077 ops->destroy(qdisc);
1078
1079 lockdep_unregister_key(&qdisc->root_lock_key);
1080 module_put(ops->owner);
1081 netdev_put(dev, &qdisc->dev_tracker);
1082
1083 trace_qdisc_destroy(qdisc);
1084
1085 call_rcu(&qdisc->rcu, qdisc_free_cb);
1086 }
1087
1088 void qdisc_destroy(struct Qdisc *qdisc)
1089 {
1090 if (qdisc->flags & TCQ_F_BUILTIN)
1091 return;
1092
1093 __qdisc_destroy(qdisc);
1094 }
1095
1096 void qdisc_put(struct Qdisc *qdisc)
1097 {
1098 if (!qdisc)
1099 return;
1100
1101 if (qdisc->flags & TCQ_F_BUILTIN ||
1102 !refcount_dec_and_test(&qdisc->refcnt))
1103 return;
1104
1105 __qdisc_destroy(qdisc);
1106 }
1107 EXPORT_SYMBOL(qdisc_put);
1108
1109 /* Version of qdisc_put() that is called with rtnl mutex unlocked.
1110 * Intended to be used as optimization, this function only takes rtnl lock if
1111 * qdisc reference counter reached zero.
1112 */
1113
1114 void qdisc_put_unlocked(struct Qdisc *qdisc)
1115 {
1116 if (qdisc->flags & TCQ_F_BUILTIN ||
1117 !refcount_dec_and_rtnl_lock(&qdisc->refcnt))
1118 return;
1119
1120 __qdisc_destroy(qdisc);
1121 rtnl_unlock();
1122 }
1123 EXPORT_SYMBOL(qdisc_put_unlocked);
1124
1125 /* Attach toplevel qdisc to device queue. */
1126 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
1127 struct Qdisc *qdisc)
1128 {
1129 struct Qdisc *oqdisc = rtnl_dereference(dev_queue->qdisc_sleeping);
1130 spinlock_t *root_lock;
1131
1132 root_lock = qdisc_lock(oqdisc);
1133 spin_lock_bh(root_lock);
1134
1135 /* ... and graft new one */
1136 if (qdisc == NULL)
1137 qdisc = &noop_qdisc;
1138 rcu_assign_pointer(dev_queue->qdisc_sleeping, qdisc);
1139 rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
1140
1141 spin_unlock_bh(root_lock);
1142
1143 return oqdisc;
1144 }
1145 EXPORT_SYMBOL(dev_graft_qdisc);
1146
1147 static void shutdown_scheduler_queue(struct net_device *dev,
1148 struct netdev_queue *dev_queue,
1149 void *_qdisc_default)
1150 {
1151 struct Qdisc *qdisc = rtnl_dereference(dev_queue->qdisc_sleeping);
1152 struct Qdisc *qdisc_default = _qdisc_default;
1153
1154 if (qdisc) {
1155 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1156 rcu_assign_pointer(dev_queue->qdisc_sleeping, qdisc_default);
1157
1158 qdisc_put(qdisc);
1159 }
1160 }
1161
1162 static void attach_one_default_qdisc(struct net_device *dev,
1163 struct netdev_queue *dev_queue,
1164 void *_unused)
1165 {
1166 struct Qdisc *qdisc;
1167 const struct Qdisc_ops *ops = default_qdisc_ops;
1168
1169 if (dev->priv_flags & IFF_NO_QUEUE)
1170 ops = &noqueue_qdisc_ops;
1171 else if(dev->type == ARPHRD_CAN)
1172 ops = &pfifo_fast_ops;
1173
1174 qdisc = qdisc_create_dflt(dev_queue, ops, TC_H_ROOT, NULL);
1175 if (!qdisc)
1176 return;
1177
1178 if (!netif_is_multiqueue(dev))
1179 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
1180 rcu_assign_pointer(dev_queue->qdisc_sleeping, qdisc);
1181 }
1182
1183 static void attach_default_qdiscs(struct net_device *dev)
1184 {
1185 struct netdev_queue *txq;
1186 struct Qdisc *qdisc;
1187
1188 txq = netdev_get_tx_queue(dev, 0);
1189
1190 if (!netif_is_multiqueue(dev) ||
1191 dev->priv_flags & IFF_NO_QUEUE) {
1192 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
1193 qdisc = rtnl_dereference(txq->qdisc_sleeping);
1194 rcu_assign_pointer(dev->qdisc, qdisc);
1195 qdisc_refcount_inc(qdisc);
1196 } else {
1197 qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT, NULL);
1198 if (qdisc) {
1199 rcu_assign_pointer(dev->qdisc, qdisc);
1200 qdisc->ops->attach(qdisc);
1201 }
1202 }
1203 qdisc = rtnl_dereference(dev->qdisc);
1204
1205 /* Detect default qdisc setup/init failed and fallback to "noqueue" */
1206 if (qdisc == &noop_qdisc) {
1207 netdev_warn(dev, "default qdisc (%s) fail, fallback to %s\n",
1208 default_qdisc_ops->id, noqueue_qdisc_ops.id);
1209 netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
1210 dev->priv_flags |= IFF_NO_QUEUE;
1211 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
1212 qdisc = rtnl_dereference(txq->qdisc_sleeping);
1213 rcu_assign_pointer(dev->qdisc, qdisc);
1214 qdisc_refcount_inc(qdisc);
1215 dev->priv_flags ^= IFF_NO_QUEUE;
1216 }
1217
1218 #ifdef CONFIG_NET_SCHED
1219 if (qdisc != &noop_qdisc)
1220 qdisc_hash_add(qdisc, false);
1221 #endif
1222 }
1223
1224 static void transition_one_qdisc(struct net_device *dev,
1225 struct netdev_queue *dev_queue,
1226 void *_need_watchdog)
1227 {
1228 struct Qdisc *new_qdisc = rtnl_dereference(dev_queue->qdisc_sleeping);
1229 int *need_watchdog_p = _need_watchdog;
1230
1231 if (!(new_qdisc->flags & TCQ_F_BUILTIN))
1232 clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
1233
1234 rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
1235 if (need_watchdog_p) {
1236 WRITE_ONCE(dev_queue->trans_start, 0);
1237 *need_watchdog_p = 1;
1238 }
1239 }
1240
1241 void dev_activate(struct net_device *dev)
1242 {
1243 int need_watchdog;
1244
1245 /* No queueing discipline is attached to device;
1246 * create default one for devices, which need queueing
1247 * and noqueue_qdisc for virtual interfaces
1248 */
1249
1250 if (rtnl_dereference(dev->qdisc) == &noop_qdisc)
1251 attach_default_qdiscs(dev);
1252
1253 if (!netif_carrier_ok(dev))
1254 /* Delay activation until next carrier-on event */
1255 return;
1256
1257 need_watchdog = 0;
1258 netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
1259 if (dev_ingress_queue(dev))
1260 transition_one_qdisc(dev, dev_ingress_queue(dev), NULL);
1261
1262 if (need_watchdog) {
1263 netif_trans_update(dev);
1264 dev_watchdog_up(dev);
1265 }
1266 }
1267 EXPORT_SYMBOL(dev_activate);
1268
1269 static void qdisc_deactivate(struct Qdisc *qdisc)
1270 {
1271 if (qdisc->flags & TCQ_F_BUILTIN)
1272 return;
1273
1274 set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
1275 }
1276
1277 static void dev_deactivate_queue(struct net_device *dev,
1278 struct netdev_queue *dev_queue,
1279 void *_qdisc_default)
1280 {
1281 struct Qdisc *qdisc_default = _qdisc_default;
1282 struct Qdisc *qdisc;
1283
1284 qdisc = rtnl_dereference(dev_queue->qdisc);
1285 if (qdisc) {
1286 qdisc_deactivate(qdisc);
1287 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1288 }
1289 }
1290
1291 static void dev_reset_queue(struct net_device *dev,
1292 struct netdev_queue *dev_queue,
1293 void *_unused)
1294 {
1295 struct Qdisc *qdisc;
1296 bool nolock;
1297
1298 qdisc = rtnl_dereference(dev_queue->qdisc_sleeping);
1299 if (!qdisc)
1300 return;
1301
1302 nolock = qdisc->flags & TCQ_F_NOLOCK;
1303
1304 if (nolock)
1305 spin_lock_bh(&qdisc->seqlock);
1306 spin_lock_bh(qdisc_lock(qdisc));
1307
1308 qdisc_reset(qdisc);
1309
1310 spin_unlock_bh(qdisc_lock(qdisc));
1311 if (nolock) {
1312 clear_bit(__QDISC_STATE_MISSED, &qdisc->state);
1313 clear_bit(__QDISC_STATE_DRAINING, &qdisc->state);
1314 spin_unlock_bh(&qdisc->seqlock);
1315 }
1316 }
1317
1318 static bool some_qdisc_is_busy(struct net_device *dev)
1319 {
1320 unsigned int i;
1321
1322 for (i = 0; i < dev->num_tx_queues; i++) {
1323 struct netdev_queue *dev_queue;
1324 spinlock_t *root_lock;
1325 struct Qdisc *q;
1326 int val;
1327
1328 dev_queue = netdev_get_tx_queue(dev, i);
1329 q = rtnl_dereference(dev_queue->qdisc_sleeping);
1330
1331 root_lock = qdisc_lock(q);
1332 spin_lock_bh(root_lock);
1333
1334 val = (qdisc_is_running(q) ||
1335 test_bit(__QDISC_STATE_SCHED, &q->state));
1336
1337 spin_unlock_bh(root_lock);
1338
1339 if (val)
1340 return true;
1341 }
1342 return false;
1343 }
1344
1345 /**
1346 * dev_deactivate_many - deactivate transmissions on several devices
1347 * @head: list of devices to deactivate
1348 *
1349 * This function returns only when all outstanding transmissions
1350 * have completed, unless all devices are in dismantle phase.
1351 */
1352 void dev_deactivate_many(struct list_head *head)
1353 {
1354 struct net_device *dev;
1355
1356 list_for_each_entry(dev, head, close_list) {
1357 netdev_for_each_tx_queue(dev, dev_deactivate_queue,
1358 &noop_qdisc);
1359 if (dev_ingress_queue(dev))
1360 dev_deactivate_queue(dev, dev_ingress_queue(dev),
1361 &noop_qdisc);
1362
1363 dev_watchdog_down(dev);
1364 }
1365
1366 /* Wait for outstanding qdisc-less dev_queue_xmit calls or
1367 * outstanding qdisc enqueuing calls.
1368 * This is avoided if all devices are in dismantle phase :
1369 * Caller will call synchronize_net() for us
1370 */
1371 synchronize_net();
1372
1373 list_for_each_entry(dev, head, close_list) {
1374 netdev_for_each_tx_queue(dev, dev_reset_queue, NULL);
1375
1376 if (dev_ingress_queue(dev))
1377 dev_reset_queue(dev, dev_ingress_queue(dev), NULL);
1378 }
1379
1380 /* Wait for outstanding qdisc_run calls. */
1381 list_for_each_entry(dev, head, close_list) {
1382 while (some_qdisc_is_busy(dev)) {
1383 /* wait_event() would avoid this sleep-loop but would
1384 * require expensive checks in the fast paths of packet
1385 * processing which isn't worth it.
1386 */
1387 schedule_timeout_uninterruptible(1);
1388 }
1389 }
1390 }
1391
1392 void dev_deactivate(struct net_device *dev)
1393 {
1394 LIST_HEAD(single);
1395
1396 list_add(&dev->close_list, &single);
1397 dev_deactivate_many(&single);
1398 list_del(&single);
1399 }
1400 EXPORT_SYMBOL(dev_deactivate);
1401
1402 static int qdisc_change_tx_queue_len(struct net_device *dev,
1403 struct netdev_queue *dev_queue)
1404 {
1405 struct Qdisc *qdisc = rtnl_dereference(dev_queue->qdisc_sleeping);
1406 const struct Qdisc_ops *ops = qdisc->ops;
1407
1408 if (ops->change_tx_queue_len)
1409 return ops->change_tx_queue_len(qdisc, dev->tx_queue_len);
1410 return 0;
1411 }
1412
1413 void dev_qdisc_change_real_num_tx(struct net_device *dev,
1414 unsigned int new_real_tx)
1415 {
1416 struct Qdisc *qdisc = rtnl_dereference(dev->qdisc);
1417
1418 if (qdisc->ops->change_real_num_tx)
1419 qdisc->ops->change_real_num_tx(qdisc, new_real_tx);
1420 }
1421
1422 void mq_change_real_num_tx(struct Qdisc *sch, unsigned int new_real_tx)
1423 {
1424 #ifdef CONFIG_NET_SCHED
1425 struct net_device *dev = qdisc_dev(sch);
1426 struct Qdisc *qdisc;
1427 unsigned int i;
1428
1429 for (i = new_real_tx; i < dev->real_num_tx_queues; i++) {
1430 qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc_sleeping);
1431 /* Only update the default qdiscs we created,
1432 * qdiscs with handles are always hashed.
1433 */
1434 if (qdisc != &noop_qdisc && !qdisc->handle)
1435 qdisc_hash_del(qdisc);
1436 }
1437 for (i = dev->real_num_tx_queues; i < new_real_tx; i++) {
1438 qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc_sleeping);
1439 if (qdisc != &noop_qdisc && !qdisc->handle)
1440 qdisc_hash_add(qdisc, false);
1441 }
1442 #endif
1443 }
1444 EXPORT_SYMBOL(mq_change_real_num_tx);
1445
1446 int dev_qdisc_change_tx_queue_len(struct net_device *dev)
1447 {
1448 bool up = dev->flags & IFF_UP;
1449 unsigned int i;
1450 int ret = 0;
1451
1452 if (up)
1453 dev_deactivate(dev);
1454
1455 for (i = 0; i < dev->num_tx_queues; i++) {
1456 ret = qdisc_change_tx_queue_len(dev, &dev->_tx[i]);
1457
1458 /* TODO: revert changes on a partial failure */
1459 if (ret)
1460 break;
1461 }
1462
1463 if (up)
1464 dev_activate(dev);
1465 return ret;
1466 }
1467
1468 static void dev_init_scheduler_queue(struct net_device *dev,
1469 struct netdev_queue *dev_queue,
1470 void *_qdisc)
1471 {
1472 struct Qdisc *qdisc = _qdisc;
1473
1474 rcu_assign_pointer(dev_queue->qdisc, qdisc);
1475 rcu_assign_pointer(dev_queue->qdisc_sleeping, qdisc);
1476 }
1477
1478 void dev_init_scheduler(struct net_device *dev)
1479 {
1480 rcu_assign_pointer(dev->qdisc, &noop_qdisc);
1481 netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
1482 if (dev_ingress_queue(dev))
1483 dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1484
1485 timer_setup(&dev->watchdog_timer, dev_watchdog, 0);
1486 }
1487
1488 void dev_shutdown(struct net_device *dev)
1489 {
1490 netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
1491 if (dev_ingress_queue(dev))
1492 shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1493 qdisc_put(rtnl_dereference(dev->qdisc));
1494 rcu_assign_pointer(dev->qdisc, &noop_qdisc);
1495
1496 WARN_ON(timer_pending(&dev->watchdog_timer));
1497 }
1498
1499 /**
1500 * psched_ratecfg_precompute__() - Pre-compute values for reciprocal division
1501 * @rate: Rate to compute reciprocal division values of
1502 * @mult: Multiplier for reciprocal division
1503 * @shift: Shift for reciprocal division
1504 *
1505 * The multiplier and shift for reciprocal division by rate are stored
1506 * in mult and shift.
1507 *
1508 * The deal here is to replace a divide by a reciprocal one
1509 * in fast path (a reciprocal divide is a multiply and a shift)
1510 *
1511 * Normal formula would be :
1512 * time_in_ns = (NSEC_PER_SEC * len) / rate_bps
1513 *
1514 * We compute mult/shift to use instead :
1515 * time_in_ns = (len * mult) >> shift;
1516 *
1517 * We try to get the highest possible mult value for accuracy,
1518 * but have to make sure no overflows will ever happen.
1519 *
1520 * reciprocal_value() is not used here it doesn't handle 64-bit values.
1521 */
1522 static void psched_ratecfg_precompute__(u64 rate, u32 *mult, u8 *shift)
1523 {
1524 u64 factor = NSEC_PER_SEC;
1525
1526 *mult = 1;
1527 *shift = 0;
1528
1529 if (rate <= 0)
1530 return;
1531
1532 for (;;) {
1533 *mult = div64_u64(factor, rate);
1534 if (*mult & (1U << 31) || factor & (1ULL << 63))
1535 break;
1536 factor <<= 1;
1537 (*shift)++;
1538 }
1539 }
1540
1541 void psched_ratecfg_precompute(struct psched_ratecfg *r,
1542 const struct tc_ratespec *conf,
1543 u64 rate64)
1544 {
1545 memset(r, 0, sizeof(*r));
1546 r->overhead = conf->overhead;
1547 r->mpu = conf->mpu;
1548 r->rate_bytes_ps = max_t(u64, conf->rate, rate64);
1549 r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK);
1550 psched_ratecfg_precompute__(r->rate_bytes_ps, &r->mult, &r->shift);
1551 }
1552 EXPORT_SYMBOL(psched_ratecfg_precompute);
1553
1554 void psched_ppscfg_precompute(struct psched_pktrate *r, u64 pktrate64)
1555 {
1556 r->rate_pkts_ps = pktrate64;
1557 psched_ratecfg_precompute__(r->rate_pkts_ps, &r->mult, &r->shift);
1558 }
1559 EXPORT_SYMBOL(psched_ppscfg_precompute);
1560
1561 void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp,
1562 struct tcf_proto *tp_head)
1563 {
1564 /* Protected with chain0->filter_chain_lock.
1565 * Can't access chain directly because tp_head can be NULL.
1566 */
1567 struct mini_Qdisc *miniq_old =
1568 rcu_dereference_protected(*miniqp->p_miniq, 1);
1569 struct mini_Qdisc *miniq;
1570
1571 if (!tp_head) {
1572 RCU_INIT_POINTER(*miniqp->p_miniq, NULL);
1573 } else {
1574 miniq = miniq_old != &miniqp->miniq1 ?
1575 &miniqp->miniq1 : &miniqp->miniq2;
1576
1577 /* We need to make sure that readers won't see the miniq
1578 * we are about to modify. So ensure that at least one RCU
1579 * grace period has elapsed since the miniq was made
1580 * inactive.
1581 */
1582 if (IS_ENABLED(CONFIG_PREEMPT_RT))
1583 cond_synchronize_rcu(miniq->rcu_state);
1584 else if (!poll_state_synchronize_rcu(miniq->rcu_state))
1585 synchronize_rcu_expedited();
1586
1587 miniq->filter_list = tp_head;
1588 rcu_assign_pointer(*miniqp->p_miniq, miniq);
1589 }
1590
1591 if (miniq_old)
1592 /* This is counterpart of the rcu sync above. We need to
1593 * block potential new user of miniq_old until all readers
1594 * are not seeing it.
1595 */
1596 miniq_old->rcu_state = start_poll_synchronize_rcu();
1597 }
1598 EXPORT_SYMBOL(mini_qdisc_pair_swap);
1599
1600 void mini_qdisc_pair_block_init(struct mini_Qdisc_pair *miniqp,
1601 struct tcf_block *block)
1602 {
1603 miniqp->miniq1.block = block;
1604 miniqp->miniq2.block = block;
1605 }
1606 EXPORT_SYMBOL(mini_qdisc_pair_block_init);
1607
1608 void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc,
1609 struct mini_Qdisc __rcu **p_miniq)
1610 {
1611 miniqp->miniq1.cpu_bstats = qdisc->cpu_bstats;
1612 miniqp->miniq1.cpu_qstats = qdisc->cpu_qstats;
1613 miniqp->miniq2.cpu_bstats = qdisc->cpu_bstats;
1614 miniqp->miniq2.cpu_qstats = qdisc->cpu_qstats;
1615 miniqp->miniq1.rcu_state = get_state_synchronize_rcu();
1616 miniqp->miniq2.rcu_state = miniqp->miniq1.rcu_state;
1617 miniqp->p_miniq = p_miniq;
1618 }
1619 EXPORT_SYMBOL(mini_qdisc_pair_init);
1620
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