projects / deliverable / linux.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
treewide: replace dev->trans_start update with helper
[deliverable/linux.git] / net / sched / sch_generic.c
1 /*
2 * net/sched/sch_generic.c Generic packet scheduler routines.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 * Jamal Hadi Salim, <hadi@cyberus.ca> 990601
11 * - Ingress support
12 */
13
14 #include <linux/bitops.h>
15 #include <linux/module.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/sched.h>
19 #include <linux/string.h>
20 #include <linux/errno.h>
21 #include <linux/netdevice.h>
22 #include <linux/skbuff.h>
23 #include <linux/rtnetlink.h>
24 #include <linux/init.h>
25 #include <linux/rcupdate.h>
26 #include <linux/list.h>
27 #include <linux/slab.h>
28 #include <linux/if_vlan.h>
29 #include <net/sch_generic.h>
30 #include <net/pkt_sched.h>
31 #include <net/dst.h>
32
33 /* Qdisc to use by default */
34 const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops;
35 EXPORT_SYMBOL(default_qdisc_ops);
36
37 /* Main transmission queue. */
38
39 /* Modifications to data participating in scheduling must be protected with
40 * qdisc_lock(qdisc) spinlock.
41 *
42 * The idea is the following:
43 * - enqueue, dequeue are serialized via qdisc root lock
44 * - ingress filtering is also serialized via qdisc root lock
45 * - updates to tree and tree walking are only done under the rtnl mutex.
46 */
47
48 static inline int dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
49 {
50 q->gso_skb = skb;
51 q->qstats.requeues++;
52 q->q.qlen++; /* it's still part of the queue */
53 __netif_schedule(q);
54
55 return 0;
56 }
57
58 static void try_bulk_dequeue_skb(struct Qdisc *q,
59 struct sk_buff *skb,
60 const struct netdev_queue *txq,
61 int *packets)
62 {
63 int bytelimit = qdisc_avail_bulklimit(txq) - skb->len;
64
65 while (bytelimit > 0) {
66 struct sk_buff *nskb = q->dequeue(q);
67
68 if (!nskb)
69 break;
70
71 bytelimit -= nskb->len; /* covers GSO len */
72 skb->next = nskb;
73 skb = nskb;
74 (*packets)++; /* GSO counts as one pkt */
75 }
76 skb->next = NULL;
77 }
78
79 /* Note that dequeue_skb can possibly return a SKB list (via skb->next).
80 * A requeued skb (via q->gso_skb) can also be a SKB list.
81 */
82 static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
83 int *packets)
84 {
85 struct sk_buff *skb = q->gso_skb;
86 const struct netdev_queue *txq = q->dev_queue;
87
88 *packets = 1;
89 *validate = true;
90 if (unlikely(skb)) {
91 /* check the reason of requeuing without tx lock first */
92 txq = skb_get_tx_queue(txq->dev, skb);
93 if (!netif_xmit_frozen_or_stopped(txq)) {
94 q->gso_skb = NULL;
95 q->q.qlen--;
96 } else
97 skb = NULL;
98 /* skb in gso_skb were already validated */
99 *validate = false;
100 } else {
101 if (!(q->flags & TCQ_F_ONETXQUEUE) ||
102 !netif_xmit_frozen_or_stopped(txq)) {
103 skb = q->dequeue(q);
104 if (skb && qdisc_may_bulk(q))
105 try_bulk_dequeue_skb(q, skb, txq, packets);
106 }
107 }
108 return skb;
109 }
110
111 /*
112 * Transmit possibly several skbs, and handle the return status as
113 * required. Holding the __QDISC___STATE_RUNNING bit guarantees that
114 * only one CPU can execute this function.
115 *
116 * Returns to the caller:
117 * 0 - queue is empty or throttled.
118 * >0 - queue is not empty.
119 */
120 int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
121 struct net_device *dev, struct netdev_queue *txq,
122 spinlock_t *root_lock, bool validate)
123 {
124 int ret = NETDEV_TX_BUSY;
125
126 /* And release qdisc */
127 spin_unlock(root_lock);
128
129 /* Note that we validate skb (GSO, checksum, ...) outside of locks */
130 if (validate)
131 skb = validate_xmit_skb_list(skb, dev);
132
133 if (likely(skb)) {
134 HARD_TX_LOCK(dev, txq, smp_processor_id());
135 if (!netif_xmit_frozen_or_stopped(txq))
136 skb = dev_hard_start_xmit(skb, dev, txq, &ret);
137
138 HARD_TX_UNLOCK(dev, txq);
139 } else {
140 spin_lock(root_lock);
141 return qdisc_qlen(q);
142 }
143 spin_lock(root_lock);
144
145 if (dev_xmit_complete(ret)) {
146 /* Driver sent out skb successfully or skb was consumed */
147 ret = qdisc_qlen(q);
148 } else {
149 /* Driver returned NETDEV_TX_BUSY - requeue skb */
150 if (unlikely(ret != NETDEV_TX_BUSY))
151 net_warn_ratelimited("BUG %s code %d qlen %d\n",
152 dev->name, ret, q->q.qlen);
153
154 ret = dev_requeue_skb(skb, q);
155 }
156
157 if (ret && netif_xmit_frozen_or_stopped(txq))
158 ret = 0;
159
160 return ret;
161 }
162
163 /*
164 * NOTE: Called under qdisc_lock(q) with locally disabled BH.
165 *
166 * __QDISC___STATE_RUNNING guarantees only one CPU can process
167 * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
168 * this queue.
169 *
170 * netif_tx_lock serializes accesses to device driver.
171 *
172 * qdisc_lock(q) and netif_tx_lock are mutually exclusive,
173 * if one is grabbed, another must be free.
174 *
175 * Note, that this procedure can be called by a watchdog timer
176 *
177 * Returns to the caller:
178 * 0 - queue is empty or throttled.
179 * >0 - queue is not empty.
180 *
181 */
182 static inline int qdisc_restart(struct Qdisc *q, int *packets)
183 {
184 struct netdev_queue *txq;
185 struct net_device *dev;
186 spinlock_t *root_lock;
187 struct sk_buff *skb;
188 bool validate;
189
190 /* Dequeue packet */
191 skb = dequeue_skb(q, &validate, packets);
192 if (unlikely(!skb))
193 return 0;
194
195 root_lock = qdisc_lock(q);
196 dev = qdisc_dev(q);
197 txq = skb_get_tx_queue(dev, skb);
198
199 return sch_direct_xmit(skb, q, dev, txq, root_lock, validate);
200 }
201
202 void __qdisc_run(struct Qdisc *q)
203 {
204 int quota = weight_p;
205 int packets;
206
207 while (qdisc_restart(q, &packets)) {
208 /*
209 * Ordered by possible occurrence: Postpone processing if
210 * 1. we've exceeded packet quota
211 * 2. another process needs the CPU;
212 */
213 quota -= packets;
214 if (quota <= 0 || need_resched()) {
215 __netif_schedule(q);
216 break;
217 }
218 }
219
220 qdisc_run_end(q);
221 }
222
223 unsigned long dev_trans_start(struct net_device *dev)
224 {
225 unsigned long val, res;
226 unsigned int i;
227
228 if (is_vlan_dev(dev))
229 dev = vlan_dev_real_dev(dev);
230 res = dev->trans_start;
231 for (i = 0; i < dev->num_tx_queues; i++) {
232 val = netdev_get_tx_queue(dev, i)->trans_start;
233 if (val && time_after(val, res))
234 res = val;
235 }
236 dev->trans_start = res;
237
238 return res;
239 }
240 EXPORT_SYMBOL(dev_trans_start);
241
242 static void dev_watchdog(unsigned long arg)
243 {
244 struct net_device *dev = (struct net_device *)arg;
245
246 netif_tx_lock(dev);
247 if (!qdisc_tx_is_noop(dev)) {
248 if (netif_device_present(dev) &&
249 netif_running(dev) &&
250 netif_carrier_ok(dev)) {
251 int some_queue_timedout = 0;
252 unsigned int i;
253 unsigned long trans_start;
254
255 for (i = 0; i < dev->num_tx_queues; i++) {
256 struct netdev_queue *txq;
257
258 txq = netdev_get_tx_queue(dev, i);
259 /*
260 * old device drivers set dev->trans_start
261 */
262 trans_start = txq->trans_start ? : dev->trans_start;
263 if (netif_xmit_stopped(txq) &&
264 time_after(jiffies, (trans_start +
265 dev->watchdog_timeo))) {
266 some_queue_timedout = 1;
267 txq->trans_timeout++;
268 break;
269 }
270 }
271
272 if (some_queue_timedout) {
273 WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",
274 dev->name, netdev_drivername(dev), i);
275 dev->netdev_ops->ndo_tx_timeout(dev);
276 }
277 if (!mod_timer(&dev->watchdog_timer,
278 round_jiffies(jiffies +
279 dev->watchdog_timeo)))
280 dev_hold(dev);
281 }
282 }
283 netif_tx_unlock(dev);
284
285 dev_put(dev);
286 }
287
288 void __netdev_watchdog_up(struct net_device *dev)
289 {
290 if (dev->netdev_ops->ndo_tx_timeout) {
291 if (dev->watchdog_timeo <= 0)
292 dev->watchdog_timeo = 5*HZ;
293 if (!mod_timer(&dev->watchdog_timer,
294 round_jiffies(jiffies + dev->watchdog_timeo)))
295 dev_hold(dev);
296 }
297 }
298
299 static void dev_watchdog_up(struct net_device *dev)
300 {
301 __netdev_watchdog_up(dev);
302 }
303
304 static void dev_watchdog_down(struct net_device *dev)
305 {
306 netif_tx_lock_bh(dev);
307 if (del_timer(&dev->watchdog_timer))
308 dev_put(dev);
309 netif_tx_unlock_bh(dev);
310 }
311
312 /**
313 * netif_carrier_on - set carrier
314 * @dev: network device
315 *
316 * Device has detected that carrier.
317 */
318 void netif_carrier_on(struct net_device *dev)
319 {
320 if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
321 if (dev->reg_state == NETREG_UNINITIALIZED)
322 return;
323 atomic_inc(&dev->carrier_changes);
324 linkwatch_fire_event(dev);
325 if (netif_running(dev))
326 __netdev_watchdog_up(dev);
327 }
328 }
329 EXPORT_SYMBOL(netif_carrier_on);
330
331 /**
332 * netif_carrier_off - clear carrier
333 * @dev: network device
334 *
335 * Device has detected loss of carrier.
336 */
337 void netif_carrier_off(struct net_device *dev)
338 {
339 if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
340 if (dev->reg_state == NETREG_UNINITIALIZED)
341 return;
342 atomic_inc(&dev->carrier_changes);
343 linkwatch_fire_event(dev);
344 }
345 }
346 EXPORT_SYMBOL(netif_carrier_off);
347
348 /* "NOOP" scheduler: the best scheduler, recommended for all interfaces
349 under all circumstances. It is difficult to invent anything faster or
350 cheaper.
351 */
352
353 static int noop_enqueue(struct sk_buff *skb, struct Qdisc *qdisc)
354 {
355 kfree_skb(skb);
356 return NET_XMIT_CN;
357 }
358
359 static struct sk_buff *noop_dequeue(struct Qdisc *qdisc)
360 {
361 return NULL;
362 }
363
364 struct Qdisc_ops noop_qdisc_ops __read_mostly = {
365 .id = "noop",
366 .priv_size = 0,
367 .enqueue = noop_enqueue,
368 .dequeue = noop_dequeue,
369 .peek = noop_dequeue,
370 .owner = THIS_MODULE,
371 };
372
373 static struct netdev_queue noop_netdev_queue = {
374 .qdisc = &noop_qdisc,
375 .qdisc_sleeping = &noop_qdisc,
376 };
377
378 struct Qdisc noop_qdisc = {
379 .enqueue = noop_enqueue,
380 .dequeue = noop_dequeue,
381 .flags = TCQ_F_BUILTIN,
382 .ops = &noop_qdisc_ops,
383 .list = LIST_HEAD_INIT(noop_qdisc.list),
384 .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
385 .dev_queue = &noop_netdev_queue,
386 .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
387 };
388 EXPORT_SYMBOL(noop_qdisc);
389
390 static int noqueue_init(struct Qdisc *qdisc, struct nlattr *opt)
391 {
392 /* register_qdisc() assigns a default of noop_enqueue if unset,
393 * but __dev_queue_xmit() treats noqueue only as such
394 * if this is NULL - so clear it here. */
395 qdisc->enqueue = NULL;
396 return 0;
397 }
398
399 struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
400 .id = "noqueue",
401 .priv_size = 0,
402 .init = noqueue_init,
403 .enqueue = noop_enqueue,
404 .dequeue = noop_dequeue,
405 .peek = noop_dequeue,
406 .owner = THIS_MODULE,
407 };
408
409 static const u8 prio2band[TC_PRIO_MAX + 1] = {
410 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1
411 };
412
413 /* 3-band FIFO queue: old style, but should be a bit faster than
414 generic prio+fifo combination.
415 */
416
417 #define PFIFO_FAST_BANDS 3
418
419 /*
420 * Private data for a pfifo_fast scheduler containing:
421 * - queues for the three band
422 * - bitmap indicating which of the bands contain skbs
423 */
424 struct pfifo_fast_priv {
425 u32 bitmap;
426 struct sk_buff_head q[PFIFO_FAST_BANDS];
427 };
428
429 /*
430 * Convert a bitmap to the first band number where an skb is queued, where:
431 * bitmap=0 means there are no skbs on any band.
432 * bitmap=1 means there is an skb on band 0.
433 * bitmap=7 means there are skbs on all 3 bands, etc.
434 */
435 static const int bitmap2band[] = {-1, 0, 1, 0, 2, 0, 1, 0};
436
437 static inline struct sk_buff_head *band2list(struct pfifo_fast_priv *priv,
438 int band)
439 {
440 return priv->q + band;
441 }
442
443 static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc)
444 {
445 if (skb_queue_len(&qdisc->q) < qdisc_dev(qdisc)->tx_queue_len) {
446 int band = prio2band[skb->priority & TC_PRIO_MAX];
447 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
448 struct sk_buff_head *list = band2list(priv, band);
449
450 priv->bitmap |= (1 << band);
451 qdisc->q.qlen++;
452 return __qdisc_enqueue_tail(skb, qdisc, list);
453 }
454
455 return qdisc_drop(skb, qdisc);
456 }
457
458 static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
459 {
460 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
461 int band = bitmap2band[priv->bitmap];
462
463 if (likely(band >= 0)) {
464 struct sk_buff_head *list = band2list(priv, band);
465 struct sk_buff *skb = __qdisc_dequeue_head(qdisc, list);
466
467 qdisc->q.qlen--;
468 if (skb_queue_empty(list))
469 priv->bitmap &= ~(1 << band);
470
471 return skb;
472 }
473
474 return NULL;
475 }
476
477 static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
478 {
479 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
480 int band = bitmap2band[priv->bitmap];
481
482 if (band >= 0) {
483 struct sk_buff_head *list = band2list(priv, band);
484
485 return skb_peek(list);
486 }
487
488 return NULL;
489 }
490
491 static void pfifo_fast_reset(struct Qdisc *qdisc)
492 {
493 int prio;
494 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
495
496 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
497 __qdisc_reset_queue(qdisc, band2list(priv, prio));
498
499 priv->bitmap = 0;
500 qdisc->qstats.backlog = 0;
501 qdisc->q.qlen = 0;
502 }
503
504 static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
505 {
506 struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
507
508 memcpy(&opt.priomap, prio2band, TC_PRIO_MAX + 1);
509 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
510 goto nla_put_failure;
511 return skb->len;
512
513 nla_put_failure:
514 return -1;
515 }
516
517 static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt)
518 {
519 int prio;
520 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
521
522 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
523 __skb_queue_head_init(band2list(priv, prio));
524
525 /* Can by-pass the queue discipline */
526 qdisc->flags |= TCQ_F_CAN_BYPASS;
527 return 0;
528 }
529
530 struct Qdisc_ops pfifo_fast_ops __read_mostly = {
531 .id = "pfifo_fast",
532 .priv_size = sizeof(struct pfifo_fast_priv),
533 .enqueue = pfifo_fast_enqueue,
534 .dequeue = pfifo_fast_dequeue,
535 .peek = pfifo_fast_peek,
536 .init = pfifo_fast_init,
537 .reset = pfifo_fast_reset,
538 .dump = pfifo_fast_dump,
539 .owner = THIS_MODULE,
540 };
541 EXPORT_SYMBOL(pfifo_fast_ops);
542
543 static struct lock_class_key qdisc_tx_busylock;
544
545 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
546 const struct Qdisc_ops *ops)
547 {
548 void *p;
549 struct Qdisc *sch;
550 unsigned int size = QDISC_ALIGN(sizeof(*sch)) + ops->priv_size;
551 int err = -ENOBUFS;
552 struct net_device *dev = dev_queue->dev;
553
554 p = kzalloc_node(size, GFP_KERNEL,
555 netdev_queue_numa_node_read(dev_queue));
556
557 if (!p)
558 goto errout;
559 sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
560 /* if we got non aligned memory, ask more and do alignment ourself */
561 if (sch != p) {
562 kfree(p);
563 p = kzalloc_node(size + QDISC_ALIGNTO - 1, GFP_KERNEL,
564 netdev_queue_numa_node_read(dev_queue));
565 if (!p)
566 goto errout;
567 sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
568 sch->padded = (char *) sch - (char *) p;
569 }
570 INIT_LIST_HEAD(&sch->list);
571 skb_queue_head_init(&sch->q);
572
573 spin_lock_init(&sch->busylock);
574 lockdep_set_class(&sch->busylock,
575 dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
576
577 sch->ops = ops;
578 sch->enqueue = ops->enqueue;
579 sch->dequeue = ops->dequeue;
580 sch->dev_queue = dev_queue;
581 dev_hold(dev);
582 atomic_set(&sch->refcnt, 1);
583
584 return sch;
585 errout:
586 return ERR_PTR(err);
587 }
588
589 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
590 const struct Qdisc_ops *ops,
591 unsigned int parentid)
592 {
593 struct Qdisc *sch;
594
595 if (!try_module_get(ops->owner))
596 goto errout;
597
598 sch = qdisc_alloc(dev_queue, ops);
599 if (IS_ERR(sch))
600 goto errout;
601 sch->parent = parentid;
602
603 if (!ops->init || ops->init(sch, NULL) == 0)
604 return sch;
605
606 qdisc_destroy(sch);
607 errout:
608 return NULL;
609 }
610 EXPORT_SYMBOL(qdisc_create_dflt);
611
612 /* Under qdisc_lock(qdisc) and BH! */
613
614 void qdisc_reset(struct Qdisc *qdisc)
615 {
616 const struct Qdisc_ops *ops = qdisc->ops;
617
618 if (ops->reset)
619 ops->reset(qdisc);
620
621 if (qdisc->gso_skb) {
622 kfree_skb_list(qdisc->gso_skb);
623 qdisc->gso_skb = NULL;
624 qdisc->q.qlen = 0;
625 }
626 }
627 EXPORT_SYMBOL(qdisc_reset);
628
629 static void qdisc_rcu_free(struct rcu_head *head)
630 {
631 struct Qdisc *qdisc = container_of(head, struct Qdisc, rcu_head);
632
633 if (qdisc_is_percpu_stats(qdisc)) {
634 free_percpu(qdisc->cpu_bstats);
635 free_percpu(qdisc->cpu_qstats);
636 }
637
638 kfree((char *) qdisc - qdisc->padded);
639 }
640
641 void qdisc_destroy(struct Qdisc *qdisc)
642 {
643 const struct Qdisc_ops *ops = qdisc->ops;
644
645 if (qdisc->flags & TCQ_F_BUILTIN ||
646 !atomic_dec_and_test(&qdisc->refcnt))
647 return;
648
649 #ifdef CONFIG_NET_SCHED
650 qdisc_list_del(qdisc);
651
652 qdisc_put_stab(rtnl_dereference(qdisc->stab));
653 #endif
654 gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est);
655 if (ops->reset)
656 ops->reset(qdisc);
657 if (ops->destroy)
658 ops->destroy(qdisc);
659
660 module_put(ops->owner);
661 dev_put(qdisc_dev(qdisc));
662
663 kfree_skb_list(qdisc->gso_skb);
664 /*
665 * gen_estimator est_timer() might access qdisc->q.lock,
666 * wait a RCU grace period before freeing qdisc.
667 */
668 call_rcu(&qdisc->rcu_head, qdisc_rcu_free);
669 }
670 EXPORT_SYMBOL(qdisc_destroy);
671
672 /* Attach toplevel qdisc to device queue. */
673 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
674 struct Qdisc *qdisc)
675 {
676 struct Qdisc *oqdisc = dev_queue->qdisc_sleeping;
677 spinlock_t *root_lock;
678
679 root_lock = qdisc_lock(oqdisc);
680 spin_lock_bh(root_lock);
681
682 /* Prune old scheduler */
683 if (oqdisc && atomic_read(&oqdisc->refcnt) <= 1)
684 qdisc_reset(oqdisc);
685
686 /* ... and graft new one */
687 if (qdisc == NULL)
688 qdisc = &noop_qdisc;
689 dev_queue->qdisc_sleeping = qdisc;
690 rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
691
692 spin_unlock_bh(root_lock);
693
694 return oqdisc;
695 }
696 EXPORT_SYMBOL(dev_graft_qdisc);
697
698 static void attach_one_default_qdisc(struct net_device *dev,
699 struct netdev_queue *dev_queue,
700 void *_unused)
701 {
702 struct Qdisc *qdisc;
703 const struct Qdisc_ops *ops = default_qdisc_ops;
704
705 if (dev->priv_flags & IFF_NO_QUEUE)
706 ops = &noqueue_qdisc_ops;
707
708 qdisc = qdisc_create_dflt(dev_queue, ops, TC_H_ROOT);
709 if (!qdisc) {
710 netdev_info(dev, "activation failed\n");
711 return;
712 }
713 if (!netif_is_multiqueue(dev))
714 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
715 dev_queue->qdisc_sleeping = qdisc;
716 }
717
718 static void attach_default_qdiscs(struct net_device *dev)
719 {
720 struct netdev_queue *txq;
721 struct Qdisc *qdisc;
722
723 txq = netdev_get_tx_queue(dev, 0);
724
725 if (!netif_is_multiqueue(dev) ||
726 dev->priv_flags & IFF_NO_QUEUE) {
727 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
728 dev->qdisc = txq->qdisc_sleeping;
729 atomic_inc(&dev->qdisc->refcnt);
730 } else {
731 qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT);
732 if (qdisc) {
733 dev->qdisc = qdisc;
734 qdisc->ops->attach(qdisc);
735 }
736 }
737 }
738
739 static void transition_one_qdisc(struct net_device *dev,
740 struct netdev_queue *dev_queue,
741 void *_need_watchdog)
742 {
743 struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
744 int *need_watchdog_p = _need_watchdog;
745
746 if (!(new_qdisc->flags & TCQ_F_BUILTIN))
747 clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
748
749 rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
750 if (need_watchdog_p) {
751 dev_queue->trans_start = 0;
752 *need_watchdog_p = 1;
753 }
754 }
755
756 void dev_activate(struct net_device *dev)
757 {
758 int need_watchdog;
759
760 /* No queueing discipline is attached to device;
761 * create default one for devices, which need queueing
762 * and noqueue_qdisc for virtual interfaces
763 */
764
765 if (dev->qdisc == &noop_qdisc)
766 attach_default_qdiscs(dev);
767
768 if (!netif_carrier_ok(dev))
769 /* Delay activation until next carrier-on event */
770 return;
771
772 need_watchdog = 0;
773 netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
774 if (dev_ingress_queue(dev))
775 transition_one_qdisc(dev, dev_ingress_queue(dev), NULL);
776
777 if (need_watchdog) {
778 netif_trans_update(dev);
779 dev_watchdog_up(dev);
780 }
781 }
782 EXPORT_SYMBOL(dev_activate);
783
784 static void dev_deactivate_queue(struct net_device *dev,
785 struct netdev_queue *dev_queue,
786 void *_qdisc_default)
787 {
788 struct Qdisc *qdisc_default = _qdisc_default;
789 struct Qdisc *qdisc;
790
791 qdisc = rtnl_dereference(dev_queue->qdisc);
792 if (qdisc) {
793 spin_lock_bh(qdisc_lock(qdisc));
794
795 if (!(qdisc->flags & TCQ_F_BUILTIN))
796 set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
797
798 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
799 qdisc_reset(qdisc);
800
801 spin_unlock_bh(qdisc_lock(qdisc));
802 }
803 }
804
805 static bool some_qdisc_is_busy(struct net_device *dev)
806 {
807 unsigned int i;
808
809 for (i = 0; i < dev->num_tx_queues; i++) {
810 struct netdev_queue *dev_queue;
811 spinlock_t *root_lock;
812 struct Qdisc *q;
813 int val;
814
815 dev_queue = netdev_get_tx_queue(dev, i);
816 q = dev_queue->qdisc_sleeping;
817 root_lock = qdisc_lock(q);
818
819 spin_lock_bh(root_lock);
820
821 val = (qdisc_is_running(q) ||
822 test_bit(__QDISC_STATE_SCHED, &q->state));
823
824 spin_unlock_bh(root_lock);
825
826 if (val)
827 return true;
828 }
829 return false;
830 }
831
832 /**
833 * dev_deactivate_many - deactivate transmissions on several devices
834 * @head: list of devices to deactivate
835 *
836 * This function returns only when all outstanding transmissions
837 * have completed, unless all devices are in dismantle phase.
838 */
839 void dev_deactivate_many(struct list_head *head)
840 {
841 struct net_device *dev;
842 bool sync_needed = false;
843
844 list_for_each_entry(dev, head, close_list) {
845 netdev_for_each_tx_queue(dev, dev_deactivate_queue,
846 &noop_qdisc);
847 if (dev_ingress_queue(dev))
848 dev_deactivate_queue(dev, dev_ingress_queue(dev),
849 &noop_qdisc);
850
851 dev_watchdog_down(dev);
852 sync_needed |= !dev->dismantle;
853 }
854
855 /* Wait for outstanding qdisc-less dev_queue_xmit calls.
856 * This is avoided if all devices are in dismantle phase :
857 * Caller will call synchronize_net() for us
858 */
859 if (sync_needed)
860 synchronize_net();
861
862 /* Wait for outstanding qdisc_run calls. */
863 list_for_each_entry(dev, head, close_list)
864 while (some_qdisc_is_busy(dev))
865 yield();
866 }
867
868 void dev_deactivate(struct net_device *dev)
869 {
870 LIST_HEAD(single);
871
872 list_add(&dev->close_list, &single);
873 dev_deactivate_many(&single);
874 list_del(&single);
875 }
876 EXPORT_SYMBOL(dev_deactivate);
877
878 static void dev_init_scheduler_queue(struct net_device *dev,
879 struct netdev_queue *dev_queue,
880 void *_qdisc)
881 {
882 struct Qdisc *qdisc = _qdisc;
883
884 rcu_assign_pointer(dev_queue->qdisc, qdisc);
885 dev_queue->qdisc_sleeping = qdisc;
886 }
887
888 void dev_init_scheduler(struct net_device *dev)
889 {
890 dev->qdisc = &noop_qdisc;
891 netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
892 if (dev_ingress_queue(dev))
893 dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
894
895 setup_timer(&dev->watchdog_timer, dev_watchdog, (unsigned long)dev);
896 }
897
898 static void shutdown_scheduler_queue(struct net_device *dev,
899 struct netdev_queue *dev_queue,
900 void *_qdisc_default)
901 {
902 struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
903 struct Qdisc *qdisc_default = _qdisc_default;
904
905 if (qdisc) {
906 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
907 dev_queue->qdisc_sleeping = qdisc_default;
908
909 qdisc_destroy(qdisc);
910 }
911 }
912
913 void dev_shutdown(struct net_device *dev)
914 {
915 netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
916 if (dev_ingress_queue(dev))
917 shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
918 qdisc_destroy(dev->qdisc);
919 dev->qdisc = &noop_qdisc;
920
921 WARN_ON(timer_pending(&dev->watchdog_timer));
922 }
923
924 void psched_ratecfg_precompute(struct psched_ratecfg *r,
925 const struct tc_ratespec *conf,
926 u64 rate64)
927 {
928 memset(r, 0, sizeof(*r));
929 r->overhead = conf->overhead;
930 r->rate_bytes_ps = max_t(u64, conf->rate, rate64);
931 r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK);
932 r->mult = 1;
933 /*
934 * The deal here is to replace a divide by a reciprocal one
935 * in fast path (a reciprocal divide is a multiply and a shift)
936 *
937 * Normal formula would be :
938 * time_in_ns = (NSEC_PER_SEC * len) / rate_bps
939 *
940 * We compute mult/shift to use instead :
941 * time_in_ns = (len * mult) >> shift;
942 *
943 * We try to get the highest possible mult value for accuracy,
944 * but have to make sure no overflows will ever happen.
945 */
946 if (r->rate_bytes_ps > 0) {
947 u64 factor = NSEC_PER_SEC;
948
949 for (;;) {
950 r->mult = div64_u64(factor, r->rate_bytes_ps);
951 if (r->mult & (1U << 31) || factor & (1ULL << 63))
952 break;
953 factor <<= 1;
954 r->shift++;
955 }
956 }
957 }
958 EXPORT_SYMBOL(psched_ratecfg_precompute);
Linux kernel - Deliverables
This page took 0.05266 seconds and 5 git commands to generate.