Line data Source code
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 */
35 : const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops;
36 : EXPORT_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 :
51 0 : static inline struct sk_buff *__skb_dequeue_bad_txq(struct Qdisc *q)
52 : {
53 0 : const struct netdev_queue *txq = q->dev_queue;
54 0 : spinlock_t *lock = NULL;
55 0 : struct sk_buff *skb;
56 :
57 0 : if (q->flags & TCQ_F_NOLOCK) {
58 0 : lock = qdisc_lock(q);
59 0 : spin_lock(lock);
60 : }
61 :
62 0 : skb = skb_peek(&q->skb_bad_txq);
63 0 : if (skb) {
64 : /* check the reason of requeuing without tx lock first */
65 0 : txq = skb_get_tx_queue(txq->dev, skb);
66 0 : if (!netif_xmit_frozen_or_stopped(txq)) {
67 0 : skb = __skb_dequeue(&q->skb_bad_txq);
68 0 : if (qdisc_is_percpu_stats(q)) {
69 0 : qdisc_qstats_cpu_backlog_dec(q, skb);
70 0 : qdisc_qstats_cpu_qlen_dec(q);
71 : } else {
72 0 : qdisc_qstats_backlog_dec(q, skb);
73 0 : q->q.qlen--;
74 : }
75 : } else {
76 : skb = SKB_XOFF_MAGIC;
77 : }
78 : }
79 :
80 0 : if (lock)
81 0 : spin_unlock(lock);
82 :
83 0 : return skb;
84 : }
85 :
86 896 : static inline struct sk_buff *qdisc_dequeue_skb_bad_txq(struct Qdisc *q)
87 : {
88 896 : struct sk_buff *skb = skb_peek(&q->skb_bad_txq);
89 :
90 896 : if (unlikely(skb))
91 0 : skb = __skb_dequeue_bad_txq(q);
92 :
93 896 : return skb;
94 : }
95 :
96 0 : static inline void qdisc_enqueue_skb_bad_txq(struct Qdisc *q,
97 : struct sk_buff *skb)
98 : {
99 0 : spinlock_t *lock = NULL;
100 :
101 0 : if (q->flags & TCQ_F_NOLOCK) {
102 0 : lock = qdisc_lock(q);
103 0 : spin_lock(lock);
104 : }
105 :
106 0 : __skb_queue_tail(&q->skb_bad_txq, skb);
107 :
108 0 : if (qdisc_is_percpu_stats(q)) {
109 0 : qdisc_qstats_cpu_backlog_inc(q, skb);
110 0 : qdisc_qstats_cpu_qlen_inc(q);
111 : } else {
112 0 : qdisc_qstats_backlog_inc(q, skb);
113 0 : q->q.qlen++;
114 : }
115 :
116 0 : if (lock)
117 0 : spin_unlock(lock);
118 0 : }
119 :
120 0 : static inline void dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
121 : {
122 0 : spinlock_t *lock = NULL;
123 :
124 0 : if (q->flags & TCQ_F_NOLOCK) {
125 0 : lock = qdisc_lock(q);
126 0 : spin_lock(lock);
127 : }
128 :
129 0 : while (skb) {
130 0 : struct sk_buff *next = skb->next;
131 :
132 0 : __skb_queue_tail(&q->gso_skb, skb);
133 :
134 : /* it's still part of the queue */
135 0 : if (qdisc_is_percpu_stats(q)) {
136 0 : qdisc_qstats_cpu_requeues_inc(q);
137 0 : qdisc_qstats_cpu_backlog_inc(q, skb);
138 0 : qdisc_qstats_cpu_qlen_inc(q);
139 : } else {
140 0 : q->qstats.requeues++;
141 0 : qdisc_qstats_backlog_inc(q, skb);
142 0 : q->q.qlen++;
143 : }
144 :
145 : skb = next;
146 : }
147 0 : if (lock)
148 0 : spin_unlock(lock);
149 0 : __netif_schedule(q);
150 0 : }
151 :
152 448 : static void try_bulk_dequeue_skb(struct Qdisc *q,
153 : struct sk_buff *skb,
154 : const struct netdev_queue *txq,
155 : int *packets)
156 : {
157 448 : int bytelimit = qdisc_avail_bulklimit(txq) - skb->len;
158 :
159 448 : while (bytelimit > 0) {
160 0 : struct sk_buff *nskb = q->dequeue(q);
161 :
162 0 : if (!nskb)
163 : break;
164 :
165 0 : bytelimit -= nskb->len; /* covers GSO len */
166 0 : skb->next = nskb;
167 0 : skb = nskb;
168 0 : (*packets)++; /* GSO counts as one pkt */
169 : }
170 448 : skb_mark_not_on_list(skb);
171 448 : }
172 :
173 : /* This variant of try_bulk_dequeue_skb() makes sure
174 : * all skbs in the chain are for the same txq
175 : */
176 0 : static void try_bulk_dequeue_skb_slow(struct Qdisc *q,
177 : struct sk_buff *skb,
178 : int *packets)
179 : {
180 0 : int mapping = skb_get_queue_mapping(skb);
181 0 : struct sk_buff *nskb;
182 0 : int cnt = 0;
183 :
184 0 : do {
185 0 : nskb = q->dequeue(q);
186 0 : if (!nskb)
187 : break;
188 0 : if (unlikely(skb_get_queue_mapping(nskb) != mapping)) {
189 0 : qdisc_enqueue_skb_bad_txq(q, nskb);
190 0 : break;
191 : }
192 0 : skb->next = nskb;
193 0 : skb = nskb;
194 0 : } while (++cnt < 8);
195 0 : (*packets) += cnt;
196 0 : skb_mark_not_on_list(skb);
197 0 : }
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 : */
202 896 : static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
203 : int *packets)
204 : {
205 896 : const struct netdev_queue *txq = q->dev_queue;
206 896 : struct sk_buff *skb = NULL;
207 :
208 896 : *packets = 1;
209 896 : if (unlikely(!skb_queue_empty(&q->gso_skb))) {
210 0 : spinlock_t *lock = NULL;
211 :
212 0 : if (q->flags & TCQ_F_NOLOCK) {
213 0 : lock = qdisc_lock(q);
214 0 : spin_lock(lock);
215 : }
216 :
217 0 : 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 0 : if (!skb) {
223 0 : if (lock)
224 0 : spin_unlock(lock);
225 0 : goto validate;
226 : }
227 :
228 : /* skb in gso_skb were already validated */
229 0 : *validate = false;
230 0 : if (xfrm_offload(skb))
231 : *validate = true;
232 : /* check the reason of requeuing without tx lock first */
233 0 : txq = skb_get_tx_queue(txq->dev, skb);
234 0 : if (!netif_xmit_frozen_or_stopped(txq)) {
235 0 : skb = __skb_dequeue(&q->gso_skb);
236 0 : if (qdisc_is_percpu_stats(q)) {
237 0 : qdisc_qstats_cpu_backlog_dec(q, skb);
238 0 : qdisc_qstats_cpu_qlen_dec(q);
239 : } else {
240 0 : qdisc_qstats_backlog_dec(q, skb);
241 0 : q->q.qlen--;
242 : }
243 : } else {
244 : skb = NULL;
245 : }
246 0 : if (lock)
247 0 : spin_unlock(lock);
248 0 : goto trace;
249 : }
250 896 : validate:
251 896 : *validate = true;
252 :
253 896 : if ((q->flags & TCQ_F_ONETXQUEUE) &&
254 896 : netif_xmit_frozen_or_stopped(txq))
255 : return skb;
256 :
257 896 : skb = qdisc_dequeue_skb_bad_txq(q);
258 896 : if (unlikely(skb)) {
259 0 : if (skb == SKB_XOFF_MAGIC)
260 : return NULL;
261 0 : goto bulk;
262 : }
263 896 : skb = q->dequeue(q);
264 896 : if (skb) {
265 448 : bulk:
266 448 : if (qdisc_may_bulk(q))
267 448 : try_bulk_dequeue_skb(q, skb, txq, packets);
268 : else
269 0 : try_bulk_dequeue_skb_slow(q, skb, packets);
270 : }
271 448 : trace:
272 896 : trace_qdisc_dequeue(q, txq, *packets, skb);
273 896 : 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 : */
285 448 : bool 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 : {
289 448 : int ret = NETDEV_TX_BUSY;
290 448 : bool again = false;
291 :
292 : /* And release qdisc */
293 448 : if (root_lock)
294 0 : spin_unlock(root_lock);
295 :
296 : /* Note that we validate skb (GSO, checksum, ...) outside of locks */
297 448 : if (validate)
298 448 : 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 :
310 448 : if (likely(skb)) {
311 448 : HARD_TX_LOCK(dev, txq, smp_processor_id());
312 448 : if (!netif_xmit_frozen_or_stopped(txq))
313 448 : skb = dev_hard_start_xmit(skb, dev, txq, &ret);
314 :
315 448 : HARD_TX_UNLOCK(dev, txq);
316 : } else {
317 0 : if (root_lock)
318 0 : spin_lock(root_lock);
319 0 : return true;
320 : }
321 :
322 448 : if (root_lock)
323 0 : spin_lock(root_lock);
324 :
325 448 : if (!dev_xmit_complete(ret)) {
326 : /* Driver returned NETDEV_TX_BUSY - requeue skb */
327 0 : if (unlikely(ret != NETDEV_TX_BUSY))
328 0 : net_warn_ratelimited("BUG %s code %d qlen %d\n",
329 : dev->name, ret, q->q.qlen);
330 :
331 0 : dev_requeue_skb(skb, q);
332 0 : 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 : */
357 896 : static inline bool qdisc_restart(struct Qdisc *q, int *packets)
358 : {
359 896 : spinlock_t *root_lock = NULL;
360 896 : struct netdev_queue *txq;
361 896 : struct net_device *dev;
362 896 : struct sk_buff *skb;
363 896 : bool validate;
364 :
365 : /* Dequeue packet */
366 896 : skb = dequeue_skb(q, &validate, packets);
367 896 : if (unlikely(!skb))
368 : return false;
369 :
370 448 : if (!(q->flags & TCQ_F_NOLOCK))
371 0 : root_lock = qdisc_lock(q);
372 :
373 448 : dev = qdisc_dev(q);
374 448 : txq = skb_get_tx_queue(dev, skb);
375 :
376 448 : return sch_direct_xmit(skb, q, dev, txq, root_lock, validate);
377 : }
378 :
379 448 : void __qdisc_run(struct Qdisc *q)
380 : {
381 448 : int quota = dev_tx_weight;
382 448 : int packets;
383 :
384 896 : while (qdisc_restart(q, &packets)) {
385 448 : quota -= packets;
386 448 : if (quota <= 0) {
387 0 : __netif_schedule(q);
388 0 : break;
389 : }
390 : }
391 448 : }
392 :
393 0 : unsigned long dev_trans_start(struct net_device *dev)
394 : {
395 0 : unsigned long val, res;
396 0 : unsigned int i;
397 :
398 0 : if (is_vlan_dev(dev))
399 0 : dev = vlan_dev_real_dev(dev);
400 0 : else if (netif_is_macvlan(dev))
401 0 : dev = macvlan_dev_real_dev(dev);
402 0 : res = netdev_get_tx_queue(dev, 0)->trans_start;
403 0 : for (i = 1; i < dev->num_tx_queues; i++) {
404 0 : val = netdev_get_tx_queue(dev, i)->trans_start;
405 0 : if (val && time_after(val, res))
406 0 : res = val;
407 : }
408 :
409 0 : return res;
410 : }
411 : EXPORT_SYMBOL(dev_trans_start);
412 :
413 0 : static void dev_watchdog(struct timer_list *t)
414 : {
415 0 : struct net_device *dev = from_timer(dev, t, watchdog_timer);
416 :
417 0 : netif_tx_lock(dev);
418 0 : if (!qdisc_tx_is_noop(dev)) {
419 0 : if (netif_device_present(dev) &&
420 0 : netif_running(dev) &&
421 0 : netif_carrier_ok(dev)) {
422 0 : int some_queue_timedout = 0;
423 : unsigned int i;
424 : unsigned long trans_start;
425 :
426 0 : for (i = 0; i < dev->num_tx_queues; i++) {
427 0 : struct netdev_queue *txq;
428 :
429 0 : txq = netdev_get_tx_queue(dev, i);
430 0 : trans_start = txq->trans_start;
431 0 : if (netif_xmit_stopped(txq) &&
432 0 : time_after(jiffies, (trans_start +
433 : dev->watchdog_timeo))) {
434 0 : some_queue_timedout = 1;
435 0 : txq->trans_timeout++;
436 0 : break;
437 : }
438 : }
439 :
440 0 : if (some_queue_timedout) {
441 0 : trace_net_dev_xmit_timeout(dev, i);
442 0 : WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",
443 : dev->name, netdev_drivername(dev), i);
444 0 : dev->netdev_ops->ndo_tx_timeout(dev, i);
445 : }
446 0 : if (!mod_timer(&dev->watchdog_timer,
447 : round_jiffies(jiffies +
448 0 : dev->watchdog_timeo)))
449 0 : dev_hold(dev);
450 : }
451 : }
452 0 : netif_tx_unlock(dev);
453 :
454 0 : dev_put(dev);
455 0 : }
456 :
457 3 : void __netdev_watchdog_up(struct net_device *dev)
458 : {
459 3 : if (dev->netdev_ops->ndo_tx_timeout) {
460 0 : if (dev->watchdog_timeo <= 0)
461 0 : dev->watchdog_timeo = 5*HZ;
462 0 : if (!mod_timer(&dev->watchdog_timer,
463 0 : round_jiffies(jiffies + dev->watchdog_timeo)))
464 0 : dev_hold(dev);
465 : }
466 3 : }
467 : EXPORT_SYMBOL_GPL(__netdev_watchdog_up);
468 :
469 3 : static void dev_watchdog_up(struct net_device *dev)
470 : {
471 3 : __netdev_watchdog_up(dev);
472 3 : }
473 :
474 0 : static void dev_watchdog_down(struct net_device *dev)
475 : {
476 0 : netif_tx_lock_bh(dev);
477 0 : if (del_timer(&dev->watchdog_timer))
478 0 : dev_put(dev);
479 0 : netif_tx_unlock_bh(dev);
480 0 : }
481 :
482 : /**
483 : * netif_carrier_on - set carrier
484 : * @dev: network device
485 : *
486 : * Device has detected acquisition of carrier.
487 : */
488 1 : void netif_carrier_on(struct net_device *dev)
489 : {
490 1 : if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
491 1 : if (dev->reg_state == NETREG_UNINITIALIZED)
492 : return;
493 1 : atomic_inc(&dev->carrier_up_count);
494 1 : linkwatch_fire_event(dev);
495 1 : if (netif_running(dev))
496 0 : __netdev_watchdog_up(dev);
497 : }
498 : }
499 : EXPORT_SYMBOL(netif_carrier_on);
500 :
501 : /**
502 : * netif_carrier_off - clear carrier
503 : * @dev: network device
504 : *
505 : * Device has detected loss of carrier.
506 : */
507 1 : void netif_carrier_off(struct net_device *dev)
508 : {
509 1 : if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
510 1 : if (dev->reg_state == NETREG_UNINITIALIZED)
511 : return;
512 1 : atomic_inc(&dev->carrier_down_count);
513 1 : linkwatch_fire_event(dev);
514 : }
515 : }
516 : EXPORT_SYMBOL(netif_carrier_off);
517 :
518 : /* "NOOP" scheduler: the best scheduler, recommended for all interfaces
519 : under all circumstances. It is difficult to invent anything faster or
520 : cheaper.
521 : */
522 :
523 0 : static int noop_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
524 : struct sk_buff **to_free)
525 : {
526 0 : __qdisc_drop(skb, to_free);
527 0 : return NET_XMIT_CN;
528 : }
529 :
530 0 : static struct sk_buff *noop_dequeue(struct Qdisc *qdisc)
531 : {
532 0 : return NULL;
533 : }
534 :
535 : struct Qdisc_ops noop_qdisc_ops __read_mostly = {
536 : .id = "noop",
537 : .priv_size = 0,
538 : .enqueue = noop_enqueue,
539 : .dequeue = noop_dequeue,
540 : .peek = noop_dequeue,
541 : .owner = THIS_MODULE,
542 : };
543 :
544 : static struct netdev_queue noop_netdev_queue = {
545 : RCU_POINTER_INITIALIZER(qdisc, &noop_qdisc),
546 : .qdisc_sleeping = &noop_qdisc,
547 : };
548 :
549 : struct Qdisc noop_qdisc = {
550 : .enqueue = noop_enqueue,
551 : .dequeue = noop_dequeue,
552 : .flags = TCQ_F_BUILTIN,
553 : .ops = &noop_qdisc_ops,
554 : .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
555 : .dev_queue = &noop_netdev_queue,
556 : .running = SEQCNT_ZERO(noop_qdisc.running),
557 : .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
558 : .gso_skb = {
559 : .next = (struct sk_buff *)&noop_qdisc.gso_skb,
560 : .prev = (struct sk_buff *)&noop_qdisc.gso_skb,
561 : .qlen = 0,
562 : .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.gso_skb.lock),
563 : },
564 : .skb_bad_txq = {
565 : .next = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
566 : .prev = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
567 : .qlen = 0,
568 : .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.skb_bad_txq.lock),
569 : },
570 : };
571 : EXPORT_SYMBOL(noop_qdisc);
572 :
573 2 : static int noqueue_init(struct Qdisc *qdisc, struct nlattr *opt,
574 : struct netlink_ext_ack *extack)
575 : {
576 : /* register_qdisc() assigns a default of noop_enqueue if unset,
577 : * but __dev_queue_xmit() treats noqueue only as such
578 : * if this is NULL - so clear it here. */
579 2 : qdisc->enqueue = NULL;
580 2 : return 0;
581 : }
582 :
583 : struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
584 : .id = "noqueue",
585 : .priv_size = 0,
586 : .init = noqueue_init,
587 : .enqueue = noop_enqueue,
588 : .dequeue = noop_dequeue,
589 : .peek = noop_dequeue,
590 : .owner = THIS_MODULE,
591 : };
592 :
593 : static const u8 prio2band[TC_PRIO_MAX + 1] = {
594 : 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1
595 : };
596 :
597 : /* 3-band FIFO queue: old style, but should be a bit faster than
598 : generic prio+fifo combination.
599 : */
600 :
601 : #define PFIFO_FAST_BANDS 3
602 :
603 : /*
604 : * Private data for a pfifo_fast scheduler containing:
605 : * - rings for priority bands
606 : */
607 : struct pfifo_fast_priv {
608 : struct skb_array q[PFIFO_FAST_BANDS];
609 : };
610 :
611 3042 : static inline struct skb_array *band2list(struct pfifo_fast_priv *priv,
612 : int band)
613 : {
614 3042 : return &priv->q[band];
615 : }
616 :
617 448 : static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
618 : struct sk_buff **to_free)
619 : {
620 448 : int band = prio2band[skb->priority & TC_PRIO_MAX];
621 448 : struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
622 448 : struct skb_array *q = band2list(priv, band);
623 448 : unsigned int pkt_len = qdisc_pkt_len(skb);
624 448 : int err;
625 :
626 448 : err = skb_array_produce(q, skb);
627 :
628 448 : if (unlikely(err)) {
629 0 : if (qdisc_is_percpu_stats(qdisc))
630 0 : return qdisc_drop_cpu(skb, qdisc, to_free);
631 : else
632 0 : return qdisc_drop(skb, qdisc, to_free);
633 : }
634 :
635 448 : qdisc_update_stats_at_enqueue(qdisc, pkt_len);
636 448 : return NET_XMIT_SUCCESS;
637 : }
638 :
639 896 : static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
640 : {
641 896 : struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
642 896 : struct sk_buff *skb = NULL;
643 896 : int band;
644 :
645 3487 : for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
646 2591 : struct skb_array *q = band2list(priv, band);
647 :
648 2591 : if (__skb_array_empty(q))
649 2143 : continue;
650 :
651 448 : skb = __skb_array_consume(q);
652 : }
653 896 : if (likely(skb)) {
654 448 : qdisc_update_stats_at_dequeue(qdisc, skb);
655 : } else {
656 448 : WRITE_ONCE(qdisc->empty, true);
657 : }
658 :
659 896 : return skb;
660 : }
661 :
662 0 : static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
663 : {
664 0 : struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
665 0 : struct sk_buff *skb = NULL;
666 0 : int band;
667 :
668 0 : for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
669 0 : struct skb_array *q = band2list(priv, band);
670 :
671 0 : skb = __skb_array_peek(q);
672 : }
673 :
674 0 : return skb;
675 : }
676 :
677 0 : static void pfifo_fast_reset(struct Qdisc *qdisc)
678 : {
679 0 : int i, band;
680 0 : struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
681 :
682 0 : for (band = 0; band < PFIFO_FAST_BANDS; band++) {
683 0 : struct skb_array *q = band2list(priv, band);
684 0 : struct sk_buff *skb;
685 :
686 : /* NULL ring is possible if destroy path is due to a failed
687 : * skb_array_init() in pfifo_fast_init() case.
688 : */
689 0 : if (!q->ring.queue)
690 0 : continue;
691 :
692 0 : while ((skb = __skb_array_consume(q)) != NULL)
693 0 : kfree_skb(skb);
694 : }
695 :
696 0 : if (qdisc_is_percpu_stats(qdisc)) {
697 0 : for_each_possible_cpu(i) {
698 0 : struct gnet_stats_queue *q;
699 :
700 0 : q = per_cpu_ptr(qdisc->cpu_qstats, i);
701 0 : q->backlog = 0;
702 0 : q->qlen = 0;
703 : }
704 : }
705 0 : }
706 :
707 0 : static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
708 : {
709 0 : struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
710 :
711 0 : memcpy(&opt.priomap, prio2band, TC_PRIO_MAX + 1);
712 0 : if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
713 0 : goto nla_put_failure;
714 0 : return skb->len;
715 :
716 0 : nla_put_failure:
717 0 : return -1;
718 : }
719 :
720 1 : static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt,
721 : struct netlink_ext_ack *extack)
722 : {
723 1 : unsigned int qlen = qdisc_dev(qdisc)->tx_queue_len;
724 1 : struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
725 1 : int prio;
726 :
727 : /* guard against zero length rings */
728 1 : if (!qlen)
729 : return -EINVAL;
730 :
731 4 : for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
732 3 : struct skb_array *q = band2list(priv, prio);
733 3 : int err;
734 :
735 3 : err = skb_array_init(q, qlen, GFP_KERNEL);
736 3 : if (err)
737 : return -ENOMEM;
738 : }
739 :
740 : /* Can by-pass the queue discipline */
741 1 : qdisc->flags |= TCQ_F_CAN_BYPASS;
742 1 : return 0;
743 : }
744 :
745 0 : static void pfifo_fast_destroy(struct Qdisc *sch)
746 : {
747 0 : struct pfifo_fast_priv *priv = qdisc_priv(sch);
748 0 : int prio;
749 :
750 0 : for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
751 0 : struct skb_array *q = band2list(priv, prio);
752 :
753 : /* NULL ring is possible if destroy path is due to a failed
754 : * skb_array_init() in pfifo_fast_init() case.
755 : */
756 0 : if (!q->ring.queue)
757 0 : continue;
758 : /* Destroy ring but no need to kfree_skb because a call to
759 : * pfifo_fast_reset() has already done that work.
760 : */
761 0 : ptr_ring_cleanup(&q->ring, NULL);
762 : }
763 0 : }
764 :
765 0 : static int pfifo_fast_change_tx_queue_len(struct Qdisc *sch,
766 : unsigned int new_len)
767 : {
768 0 : struct pfifo_fast_priv *priv = qdisc_priv(sch);
769 0 : struct skb_array *bands[PFIFO_FAST_BANDS];
770 0 : int prio;
771 :
772 0 : for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
773 0 : struct skb_array *q = band2list(priv, prio);
774 :
775 0 : bands[prio] = q;
776 : }
777 :
778 0 : return skb_array_resize_multiple(bands, PFIFO_FAST_BANDS, new_len,
779 : GFP_KERNEL);
780 : }
781 :
782 : struct Qdisc_ops pfifo_fast_ops __read_mostly = {
783 : .id = "pfifo_fast",
784 : .priv_size = sizeof(struct pfifo_fast_priv),
785 : .enqueue = pfifo_fast_enqueue,
786 : .dequeue = pfifo_fast_dequeue,
787 : .peek = pfifo_fast_peek,
788 : .init = pfifo_fast_init,
789 : .destroy = pfifo_fast_destroy,
790 : .reset = pfifo_fast_reset,
791 : .dump = pfifo_fast_dump,
792 : .change_tx_queue_len = pfifo_fast_change_tx_queue_len,
793 : .owner = THIS_MODULE,
794 : .static_flags = TCQ_F_NOLOCK | TCQ_F_CPUSTATS,
795 : };
796 : EXPORT_SYMBOL(pfifo_fast_ops);
797 :
798 : static struct lock_class_key qdisc_tx_busylock;
799 : static struct lock_class_key qdisc_running_key;
800 :
801 3 : struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
802 : const struct Qdisc_ops *ops,
803 : struct netlink_ext_ack *extack)
804 : {
805 3 : struct Qdisc *sch;
806 3 : unsigned int size = sizeof(*sch) + ops->priv_size;
807 3 : int err = -ENOBUFS;
808 3 : struct net_device *dev;
809 :
810 3 : if (!dev_queue) {
811 0 : NL_SET_ERR_MSG(extack, "No device queue given");
812 0 : err = -EINVAL;
813 0 : goto errout;
814 : }
815 :
816 3 : dev = dev_queue->dev;
817 3 : sch = kzalloc_node(size, GFP_KERNEL, netdev_queue_numa_node_read(dev_queue));
818 :
819 3 : if (!sch)
820 0 : goto errout;
821 3 : __skb_queue_head_init(&sch->gso_skb);
822 3 : __skb_queue_head_init(&sch->skb_bad_txq);
823 3 : qdisc_skb_head_init(&sch->q);
824 3 : spin_lock_init(&sch->q.lock);
825 :
826 3 : if (ops->static_flags & TCQ_F_CPUSTATS) {
827 2 : sch->cpu_bstats =
828 6 : netdev_alloc_pcpu_stats(struct gnet_stats_basic_cpu);
829 1 : if (!sch->cpu_bstats)
830 0 : goto errout1;
831 :
832 1 : sch->cpu_qstats = alloc_percpu(struct gnet_stats_queue);
833 1 : if (!sch->cpu_qstats) {
834 0 : free_percpu(sch->cpu_bstats);
835 0 : goto errout1;
836 : }
837 : }
838 :
839 3 : spin_lock_init(&sch->busylock);
840 6 : lockdep_set_class(&sch->busylock,
841 : dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
842 :
843 : /* seqlock has the same scope of busylock, for NOLOCK qdisc */
844 3 : spin_lock_init(&sch->seqlock);
845 6 : lockdep_set_class(&sch->busylock,
846 : dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
847 :
848 3 : seqcount_init(&sch->running);
849 6 : lockdep_set_class(&sch->running,
850 : dev->qdisc_running_key ?: &qdisc_running_key);
851 :
852 3 : sch->ops = ops;
853 3 : sch->flags = ops->static_flags;
854 3 : sch->enqueue = ops->enqueue;
855 3 : sch->dequeue = ops->dequeue;
856 3 : sch->dev_queue = dev_queue;
857 3 : sch->empty = true;
858 3 : dev_hold(dev);
859 3 : refcount_set(&sch->refcnt, 1);
860 :
861 3 : return sch;
862 0 : errout1:
863 0 : kfree(sch);
864 0 : errout:
865 0 : return ERR_PTR(err);
866 : }
867 :
868 3 : struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
869 : const struct Qdisc_ops *ops,
870 : unsigned int parentid,
871 : struct netlink_ext_ack *extack)
872 : {
873 3 : struct Qdisc *sch;
874 :
875 3 : if (!try_module_get(ops->owner)) {
876 : NL_SET_ERR_MSG(extack, "Failed to increase module reference counter");
877 : return NULL;
878 : }
879 :
880 3 : sch = qdisc_alloc(dev_queue, ops, extack);
881 3 : if (IS_ERR(sch)) {
882 3 : module_put(ops->owner);
883 : return NULL;
884 : }
885 3 : sch->parent = parentid;
886 :
887 3 : if (!ops->init || ops->init(sch, NULL, extack) == 0) {
888 3 : trace_qdisc_create(ops, dev_queue->dev, parentid);
889 3 : return sch;
890 : }
891 :
892 0 : qdisc_put(sch);
893 0 : return NULL;
894 : }
895 : EXPORT_SYMBOL(qdisc_create_dflt);
896 :
897 : /* Under qdisc_lock(qdisc) and BH! */
898 :
899 0 : void qdisc_reset(struct Qdisc *qdisc)
900 : {
901 0 : const struct Qdisc_ops *ops = qdisc->ops;
902 0 : struct sk_buff *skb, *tmp;
903 :
904 0 : trace_qdisc_reset(qdisc);
905 :
906 0 : if (ops->reset)
907 0 : ops->reset(qdisc);
908 :
909 0 : skb_queue_walk_safe(&qdisc->gso_skb, skb, tmp) {
910 0 : __skb_unlink(skb, &qdisc->gso_skb);
911 0 : kfree_skb_list(skb);
912 : }
913 :
914 0 : skb_queue_walk_safe(&qdisc->skb_bad_txq, skb, tmp) {
915 0 : __skb_unlink(skb, &qdisc->skb_bad_txq);
916 0 : kfree_skb_list(skb);
917 : }
918 :
919 0 : qdisc->q.qlen = 0;
920 0 : qdisc->qstats.backlog = 0;
921 0 : }
922 : EXPORT_SYMBOL(qdisc_reset);
923 :
924 0 : void qdisc_free(struct Qdisc *qdisc)
925 : {
926 0 : if (qdisc_is_percpu_stats(qdisc)) {
927 0 : free_percpu(qdisc->cpu_bstats);
928 0 : free_percpu(qdisc->cpu_qstats);
929 : }
930 :
931 0 : kfree(qdisc);
932 0 : }
933 :
934 0 : static void qdisc_free_cb(struct rcu_head *head)
935 : {
936 0 : struct Qdisc *q = container_of(head, struct Qdisc, rcu);
937 :
938 0 : qdisc_free(q);
939 0 : }
940 :
941 0 : static void qdisc_destroy(struct Qdisc *qdisc)
942 : {
943 0 : const struct Qdisc_ops *ops = qdisc->ops;
944 :
945 : #ifdef CONFIG_NET_SCHED
946 : qdisc_hash_del(qdisc);
947 :
948 : qdisc_put_stab(rtnl_dereference(qdisc->stab));
949 : #endif
950 0 : gen_kill_estimator(&qdisc->rate_est);
951 :
952 0 : qdisc_reset(qdisc);
953 :
954 0 : if (ops->destroy)
955 0 : ops->destroy(qdisc);
956 :
957 0 : module_put(ops->owner);
958 0 : dev_put(qdisc_dev(qdisc));
959 :
960 0 : trace_qdisc_destroy(qdisc);
961 :
962 0 : call_rcu(&qdisc->rcu, qdisc_free_cb);
963 0 : }
964 :
965 0 : void qdisc_put(struct Qdisc *qdisc)
966 : {
967 0 : if (!qdisc)
968 : return;
969 :
970 0 : if (qdisc->flags & TCQ_F_BUILTIN ||
971 0 : !refcount_dec_and_test(&qdisc->refcnt))
972 0 : return;
973 :
974 0 : qdisc_destroy(qdisc);
975 : }
976 : EXPORT_SYMBOL(qdisc_put);
977 :
978 : /* Version of qdisc_put() that is called with rtnl mutex unlocked.
979 : * Intended to be used as optimization, this function only takes rtnl lock if
980 : * qdisc reference counter reached zero.
981 : */
982 :
983 0 : void qdisc_put_unlocked(struct Qdisc *qdisc)
984 : {
985 0 : if (qdisc->flags & TCQ_F_BUILTIN ||
986 0 : !refcount_dec_and_rtnl_lock(&qdisc->refcnt))
987 0 : return;
988 :
989 0 : qdisc_destroy(qdisc);
990 0 : rtnl_unlock();
991 : }
992 : EXPORT_SYMBOL(qdisc_put_unlocked);
993 :
994 : /* Attach toplevel qdisc to device queue. */
995 0 : struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
996 : struct Qdisc *qdisc)
997 : {
998 0 : struct Qdisc *oqdisc = dev_queue->qdisc_sleeping;
999 0 : spinlock_t *root_lock;
1000 :
1001 0 : root_lock = qdisc_lock(oqdisc);
1002 0 : spin_lock_bh(root_lock);
1003 :
1004 : /* ... and graft new one */
1005 0 : if (qdisc == NULL)
1006 0 : qdisc = &noop_qdisc;
1007 0 : dev_queue->qdisc_sleeping = qdisc;
1008 0 : rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
1009 :
1010 0 : spin_unlock_bh(root_lock);
1011 :
1012 0 : return oqdisc;
1013 : }
1014 : EXPORT_SYMBOL(dev_graft_qdisc);
1015 :
1016 3 : static void attach_one_default_qdisc(struct net_device *dev,
1017 : struct netdev_queue *dev_queue,
1018 : void *_unused)
1019 : {
1020 3 : struct Qdisc *qdisc;
1021 3 : const struct Qdisc_ops *ops = default_qdisc_ops;
1022 :
1023 3 : if (dev->priv_flags & IFF_NO_QUEUE)
1024 : ops = &noqueue_qdisc_ops;
1025 1 : else if(dev->type == ARPHRD_CAN)
1026 0 : ops = &pfifo_fast_ops;
1027 :
1028 3 : qdisc = qdisc_create_dflt(dev_queue, ops, TC_H_ROOT, NULL);
1029 3 : if (!qdisc)
1030 : return;
1031 :
1032 3 : if (!netif_is_multiqueue(dev))
1033 3 : qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
1034 3 : dev_queue->qdisc_sleeping = qdisc;
1035 : }
1036 :
1037 3 : static void attach_default_qdiscs(struct net_device *dev)
1038 : {
1039 3 : struct netdev_queue *txq;
1040 3 : struct Qdisc *qdisc;
1041 :
1042 3 : txq = netdev_get_tx_queue(dev, 0);
1043 :
1044 3 : if (!netif_is_multiqueue(dev) ||
1045 0 : dev->priv_flags & IFF_NO_QUEUE) {
1046 3 : netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
1047 3 : dev->qdisc = txq->qdisc_sleeping;
1048 3 : qdisc_refcount_inc(dev->qdisc);
1049 : } else {
1050 0 : qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT, NULL);
1051 0 : if (qdisc) {
1052 0 : dev->qdisc = qdisc;
1053 0 : qdisc->ops->attach(qdisc);
1054 : }
1055 : }
1056 :
1057 : /* Detect default qdisc setup/init failed and fallback to "noqueue" */
1058 3 : if (dev->qdisc == &noop_qdisc) {
1059 0 : netdev_warn(dev, "default qdisc (%s) fail, fallback to %s\n",
1060 0 : default_qdisc_ops->id, noqueue_qdisc_ops.id);
1061 0 : dev->priv_flags |= IFF_NO_QUEUE;
1062 0 : netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
1063 0 : dev->qdisc = txq->qdisc_sleeping;
1064 0 : qdisc_refcount_inc(dev->qdisc);
1065 0 : dev->priv_flags ^= IFF_NO_QUEUE;
1066 : }
1067 :
1068 : #ifdef CONFIG_NET_SCHED
1069 : if (dev->qdisc != &noop_qdisc)
1070 : qdisc_hash_add(dev->qdisc, false);
1071 : #endif
1072 3 : }
1073 :
1074 3 : static void transition_one_qdisc(struct net_device *dev,
1075 : struct netdev_queue *dev_queue,
1076 : void *_need_watchdog)
1077 : {
1078 3 : struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
1079 3 : int *need_watchdog_p = _need_watchdog;
1080 :
1081 3 : if (!(new_qdisc->flags & TCQ_F_BUILTIN))
1082 3 : clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
1083 :
1084 3 : rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
1085 3 : if (need_watchdog_p) {
1086 3 : dev_queue->trans_start = 0;
1087 3 : *need_watchdog_p = 1;
1088 : }
1089 3 : }
1090 :
1091 3 : void dev_activate(struct net_device *dev)
1092 : {
1093 3 : int need_watchdog;
1094 :
1095 : /* No queueing discipline is attached to device;
1096 : * create default one for devices, which need queueing
1097 : * and noqueue_qdisc for virtual interfaces
1098 : */
1099 :
1100 3 : if (dev->qdisc == &noop_qdisc)
1101 3 : attach_default_qdiscs(dev);
1102 :
1103 3 : if (!netif_carrier_ok(dev))
1104 : /* Delay activation until next carrier-on event */
1105 0 : return;
1106 :
1107 3 : need_watchdog = 0;
1108 3 : netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
1109 3 : if (dev_ingress_queue(dev))
1110 0 : transition_one_qdisc(dev, dev_ingress_queue(dev), NULL);
1111 :
1112 3 : if (need_watchdog) {
1113 3 : netif_trans_update(dev);
1114 6 : dev_watchdog_up(dev);
1115 : }
1116 : }
1117 : EXPORT_SYMBOL(dev_activate);
1118 :
1119 0 : static void qdisc_deactivate(struct Qdisc *qdisc)
1120 : {
1121 0 : if (qdisc->flags & TCQ_F_BUILTIN)
1122 : return;
1123 :
1124 0 : set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
1125 : }
1126 :
1127 0 : static void dev_deactivate_queue(struct net_device *dev,
1128 : struct netdev_queue *dev_queue,
1129 : void *_qdisc_default)
1130 : {
1131 0 : struct Qdisc *qdisc_default = _qdisc_default;
1132 0 : struct Qdisc *qdisc;
1133 :
1134 0 : qdisc = rtnl_dereference(dev_queue->qdisc);
1135 0 : if (qdisc) {
1136 0 : qdisc_deactivate(qdisc);
1137 0 : rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1138 : }
1139 0 : }
1140 :
1141 0 : static void dev_reset_queue(struct net_device *dev,
1142 : struct netdev_queue *dev_queue,
1143 : void *_unused)
1144 : {
1145 0 : struct Qdisc *qdisc;
1146 0 : bool nolock;
1147 :
1148 0 : qdisc = dev_queue->qdisc_sleeping;
1149 0 : if (!qdisc)
1150 : return;
1151 :
1152 0 : nolock = qdisc->flags & TCQ_F_NOLOCK;
1153 :
1154 0 : if (nolock)
1155 0 : spin_lock_bh(&qdisc->seqlock);
1156 0 : spin_lock_bh(qdisc_lock(qdisc));
1157 :
1158 0 : qdisc_reset(qdisc);
1159 :
1160 0 : spin_unlock_bh(qdisc_lock(qdisc));
1161 0 : if (nolock)
1162 0 : spin_unlock_bh(&qdisc->seqlock);
1163 : }
1164 :
1165 0 : static bool some_qdisc_is_busy(struct net_device *dev)
1166 : {
1167 0 : unsigned int i;
1168 :
1169 0 : for (i = 0; i < dev->num_tx_queues; i++) {
1170 0 : struct netdev_queue *dev_queue;
1171 0 : spinlock_t *root_lock;
1172 0 : struct Qdisc *q;
1173 0 : int val;
1174 :
1175 0 : dev_queue = netdev_get_tx_queue(dev, i);
1176 0 : q = dev_queue->qdisc_sleeping;
1177 :
1178 0 : root_lock = qdisc_lock(q);
1179 0 : spin_lock_bh(root_lock);
1180 :
1181 0 : val = (qdisc_is_running(q) ||
1182 0 : test_bit(__QDISC_STATE_SCHED, &q->state));
1183 :
1184 0 : spin_unlock_bh(root_lock);
1185 :
1186 0 : if (val)
1187 : return true;
1188 : }
1189 : return false;
1190 : }
1191 :
1192 : /**
1193 : * dev_deactivate_many - deactivate transmissions on several devices
1194 : * @head: list of devices to deactivate
1195 : *
1196 : * This function returns only when all outstanding transmissions
1197 : * have completed, unless all devices are in dismantle phase.
1198 : */
1199 0 : void dev_deactivate_many(struct list_head *head)
1200 : {
1201 0 : struct net_device *dev;
1202 :
1203 0 : list_for_each_entry(dev, head, close_list) {
1204 0 : netdev_for_each_tx_queue(dev, dev_deactivate_queue,
1205 : &noop_qdisc);
1206 0 : if (dev_ingress_queue(dev))
1207 0 : dev_deactivate_queue(dev, dev_ingress_queue(dev),
1208 : &noop_qdisc);
1209 :
1210 0 : dev_watchdog_down(dev);
1211 : }
1212 :
1213 : /* Wait for outstanding qdisc-less dev_queue_xmit calls or
1214 : * outstanding qdisc enqueuing calls.
1215 : * This is avoided if all devices are in dismantle phase :
1216 : * Caller will call synchronize_net() for us
1217 : */
1218 0 : synchronize_net();
1219 :
1220 0 : list_for_each_entry(dev, head, close_list) {
1221 0 : netdev_for_each_tx_queue(dev, dev_reset_queue, NULL);
1222 :
1223 0 : if (dev_ingress_queue(dev))
1224 0 : dev_reset_queue(dev, dev_ingress_queue(dev), NULL);
1225 : }
1226 :
1227 : /* Wait for outstanding qdisc_run calls. */
1228 0 : list_for_each_entry(dev, head, close_list) {
1229 0 : while (some_qdisc_is_busy(dev)) {
1230 : /* wait_event() would avoid this sleep-loop but would
1231 : * require expensive checks in the fast paths of packet
1232 : * processing which isn't worth it.
1233 : */
1234 0 : schedule_timeout_uninterruptible(1);
1235 : }
1236 : }
1237 0 : }
1238 :
1239 0 : void dev_deactivate(struct net_device *dev)
1240 : {
1241 0 : LIST_HEAD(single);
1242 :
1243 0 : list_add(&dev->close_list, &single);
1244 0 : dev_deactivate_many(&single);
1245 0 : list_del(&single);
1246 0 : }
1247 : EXPORT_SYMBOL(dev_deactivate);
1248 :
1249 0 : static int qdisc_change_tx_queue_len(struct net_device *dev,
1250 : struct netdev_queue *dev_queue)
1251 : {
1252 0 : struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1253 0 : const struct Qdisc_ops *ops = qdisc->ops;
1254 :
1255 0 : if (ops->change_tx_queue_len)
1256 0 : return ops->change_tx_queue_len(qdisc, dev->tx_queue_len);
1257 : return 0;
1258 : }
1259 :
1260 0 : int dev_qdisc_change_tx_queue_len(struct net_device *dev)
1261 : {
1262 0 : bool up = dev->flags & IFF_UP;
1263 0 : unsigned int i;
1264 0 : int ret = 0;
1265 :
1266 0 : if (up)
1267 0 : dev_deactivate(dev);
1268 :
1269 0 : for (i = 0; i < dev->num_tx_queues; i++) {
1270 0 : ret = qdisc_change_tx_queue_len(dev, &dev->_tx[i]);
1271 :
1272 : /* TODO: revert changes on a partial failure */
1273 0 : if (ret)
1274 : break;
1275 : }
1276 :
1277 0 : if (up)
1278 0 : dev_activate(dev);
1279 0 : return ret;
1280 : }
1281 :
1282 3 : static void dev_init_scheduler_queue(struct net_device *dev,
1283 : struct netdev_queue *dev_queue,
1284 : void *_qdisc)
1285 : {
1286 3 : struct Qdisc *qdisc = _qdisc;
1287 :
1288 3 : rcu_assign_pointer(dev_queue->qdisc, qdisc);
1289 3 : dev_queue->qdisc_sleeping = qdisc;
1290 0 : }
1291 :
1292 3 : void dev_init_scheduler(struct net_device *dev)
1293 : {
1294 3 : dev->qdisc = &noop_qdisc;
1295 3 : netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
1296 3 : if (dev_ingress_queue(dev))
1297 0 : dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1298 :
1299 3 : timer_setup(&dev->watchdog_timer, dev_watchdog, 0);
1300 3 : }
1301 :
1302 0 : static void shutdown_scheduler_queue(struct net_device *dev,
1303 : struct netdev_queue *dev_queue,
1304 : void *_qdisc_default)
1305 : {
1306 0 : struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1307 0 : struct Qdisc *qdisc_default = _qdisc_default;
1308 :
1309 0 : if (qdisc) {
1310 0 : rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1311 0 : dev_queue->qdisc_sleeping = qdisc_default;
1312 :
1313 0 : qdisc_put(qdisc);
1314 : }
1315 0 : }
1316 :
1317 0 : void dev_shutdown(struct net_device *dev)
1318 : {
1319 0 : netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
1320 0 : if (dev_ingress_queue(dev))
1321 0 : shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1322 0 : qdisc_put(dev->qdisc);
1323 0 : dev->qdisc = &noop_qdisc;
1324 :
1325 0 : WARN_ON(timer_pending(&dev->watchdog_timer));
1326 0 : }
1327 :
1328 0 : void psched_ratecfg_precompute(struct psched_ratecfg *r,
1329 : const struct tc_ratespec *conf,
1330 : u64 rate64)
1331 : {
1332 0 : memset(r, 0, sizeof(*r));
1333 0 : r->overhead = conf->overhead;
1334 0 : r->rate_bytes_ps = max_t(u64, conf->rate, rate64);
1335 0 : r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK);
1336 0 : r->mult = 1;
1337 : /*
1338 : * The deal here is to replace a divide by a reciprocal one
1339 : * in fast path (a reciprocal divide is a multiply and a shift)
1340 : *
1341 : * Normal formula would be :
1342 : * time_in_ns = (NSEC_PER_SEC * len) / rate_bps
1343 : *
1344 : * We compute mult/shift to use instead :
1345 : * time_in_ns = (len * mult) >> shift;
1346 : *
1347 : * We try to get the highest possible mult value for accuracy,
1348 : * but have to make sure no overflows will ever happen.
1349 : */
1350 0 : if (r->rate_bytes_ps > 0) {
1351 : u64 factor = NSEC_PER_SEC;
1352 :
1353 0 : for (;;) {
1354 0 : r->mult = div64_u64(factor, r->rate_bytes_ps);
1355 0 : if (r->mult & (1U << 31) || factor & (1ULL << 63))
1356 : break;
1357 0 : factor <<= 1;
1358 0 : r->shift++;
1359 : }
1360 : }
1361 0 : }
1362 : EXPORT_SYMBOL(psched_ratecfg_precompute);
1363 :
1364 0 : static void mini_qdisc_rcu_func(struct rcu_head *head)
1365 : {
1366 0 : }
1367 :
1368 0 : void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp,
1369 : struct tcf_proto *tp_head)
1370 : {
1371 : /* Protected with chain0->filter_chain_lock.
1372 : * Can't access chain directly because tp_head can be NULL.
1373 : */
1374 0 : struct mini_Qdisc *miniq_old =
1375 0 : rcu_dereference_protected(*miniqp->p_miniq, 1);
1376 0 : struct mini_Qdisc *miniq;
1377 :
1378 0 : if (!tp_head) {
1379 0 : RCU_INIT_POINTER(*miniqp->p_miniq, NULL);
1380 : /* Wait for flying RCU callback before it is freed. */
1381 0 : rcu_barrier();
1382 0 : return;
1383 : }
1384 :
1385 0 : miniq = !miniq_old || miniq_old == &miniqp->miniq2 ?
1386 0 : &miniqp->miniq1 : &miniqp->miniq2;
1387 :
1388 : /* We need to make sure that readers won't see the miniq
1389 : * we are about to modify. So wait until previous call_rcu callback
1390 : * is done.
1391 : */
1392 0 : rcu_barrier();
1393 0 : miniq->filter_list = tp_head;
1394 0 : rcu_assign_pointer(*miniqp->p_miniq, miniq);
1395 :
1396 0 : if (miniq_old)
1397 : /* This is counterpart of the rcu barriers above. We need to
1398 : * block potential new user of miniq_old until all readers
1399 : * are not seeing it.
1400 : */
1401 0 : call_rcu(&miniq_old->rcu, mini_qdisc_rcu_func);
1402 : }
1403 : EXPORT_SYMBOL(mini_qdisc_pair_swap);
1404 :
1405 0 : void mini_qdisc_pair_block_init(struct mini_Qdisc_pair *miniqp,
1406 : struct tcf_block *block)
1407 : {
1408 0 : miniqp->miniq1.block = block;
1409 0 : miniqp->miniq2.block = block;
1410 0 : }
1411 : EXPORT_SYMBOL(mini_qdisc_pair_block_init);
1412 :
1413 0 : void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc,
1414 : struct mini_Qdisc __rcu **p_miniq)
1415 : {
1416 0 : miniqp->miniq1.cpu_bstats = qdisc->cpu_bstats;
1417 0 : miniqp->miniq1.cpu_qstats = qdisc->cpu_qstats;
1418 0 : miniqp->miniq2.cpu_bstats = qdisc->cpu_bstats;
1419 0 : miniqp->miniq2.cpu_qstats = qdisc->cpu_qstats;
1420 0 : miniqp->p_miniq = p_miniq;
1421 0 : }
1422 : EXPORT_SYMBOL(mini_qdisc_pair_init);
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