microblaze: uaccess: fix put_user and get_user macros
[linux-2.6.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 <net/pkt_sched.h>
28
29 /* Main transmission queue. */
30
31 /* Modifications to data participating in scheduling must be protected with
32  * qdisc_lock(qdisc) spinlock.
33  *
34  * The idea is the following:
35  * - enqueue, dequeue are serialized via qdisc root lock
36  * - ingress filtering is also serialized via qdisc root lock
37  * - updates to tree and tree walking are only done under the rtnl mutex.
38  */
39
40 static inline int dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
41 {
42         q->gso_skb = skb;
43         q->qstats.requeues++;
44         q->q.qlen++;    /* it's still part of the queue */
45         __netif_schedule(q);
46
47         return 0;
48 }
49
50 static inline struct sk_buff *dequeue_skb(struct Qdisc *q)
51 {
52         struct sk_buff *skb = q->gso_skb;
53
54         if (unlikely(skb)) {
55                 struct net_device *dev = qdisc_dev(q);
56                 struct netdev_queue *txq;
57
58                 /* check the reason of requeuing without tx lock first */
59                 txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
60                 if (!netif_tx_queue_stopped(txq) &&
61                     !netif_tx_queue_frozen(txq)) {
62                         q->gso_skb = NULL;
63                         q->q.qlen--;
64                 } else
65                         skb = NULL;
66         } else {
67                 skb = q->dequeue(q);
68         }
69
70         return skb;
71 }
72
73 static inline int handle_dev_cpu_collision(struct sk_buff *skb,
74                                            struct netdev_queue *dev_queue,
75                                            struct Qdisc *q)
76 {
77         int ret;
78
79         if (unlikely(dev_queue->xmit_lock_owner == smp_processor_id())) {
80                 /*
81                  * Same CPU holding the lock. It may be a transient
82                  * configuration error, when hard_start_xmit() recurses. We
83                  * detect it by checking xmit owner and drop the packet when
84                  * deadloop is detected. Return OK to try the next skb.
85                  */
86                 kfree_skb(skb);
87                 if (net_ratelimit())
88                         printk(KERN_WARNING "Dead loop on netdevice %s, "
89                                "fix it urgently!\n", dev_queue->dev->name);
90                 ret = qdisc_qlen(q);
91         } else {
92                 /*
93                  * Another cpu is holding lock, requeue & delay xmits for
94                  * some time.
95                  */
96                 __get_cpu_var(netdev_rx_stat).cpu_collision++;
97                 ret = dev_requeue_skb(skb, q);
98         }
99
100         return ret;
101 }
102
103 /*
104  * Transmit one skb, and handle the return status as required. Holding the
105  * __QDISC_STATE_RUNNING bit guarantees that only one CPU can execute this
106  * function.
107  *
108  * Returns to the caller:
109  *                              0  - queue is empty or throttled.
110  *                              >0 - queue is not empty.
111  */
112 int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
113                     struct net_device *dev, struct netdev_queue *txq,
114                     spinlock_t *root_lock)
115 {
116         int ret = NETDEV_TX_BUSY;
117
118         /* And release qdisc */
119         spin_unlock(root_lock);
120
121         HARD_TX_LOCK(dev, txq, smp_processor_id());
122         if (!netif_tx_queue_stopped(txq) && !netif_tx_queue_frozen(txq))
123                 ret = dev_hard_start_xmit(skb, dev, txq);
124
125         HARD_TX_UNLOCK(dev, txq);
126
127         spin_lock(root_lock);
128
129         if (dev_xmit_complete(ret)) {
130                 /* Driver sent out skb successfully or skb was consumed */
131                 ret = qdisc_qlen(q);
132         } else if (ret == NETDEV_TX_LOCKED) {
133                 /* Driver try lock failed */
134                 ret = handle_dev_cpu_collision(skb, txq, q);
135         } else {
136                 /* Driver returned NETDEV_TX_BUSY - requeue skb */
137                 if (unlikely (ret != NETDEV_TX_BUSY && net_ratelimit()))
138                         printk(KERN_WARNING "BUG %s code %d qlen %d\n",
139                                dev->name, ret, q->q.qlen);
140
141                 ret = dev_requeue_skb(skb, q);
142         }
143
144         if (ret && (netif_tx_queue_stopped(txq) ||
145                     netif_tx_queue_frozen(txq)))
146                 ret = 0;
147
148         return ret;
149 }
150
151 /*
152  * NOTE: Called under qdisc_lock(q) with locally disabled BH.
153  *
154  * __QDISC_STATE_RUNNING guarantees only one CPU can process
155  * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
156  * this queue.
157  *
158  *  netif_tx_lock serializes accesses to device driver.
159  *
160  *  qdisc_lock(q) and netif_tx_lock are mutually exclusive,
161  *  if one is grabbed, another must be free.
162  *
163  * Note, that this procedure can be called by a watchdog timer
164  *
165  * Returns to the caller:
166  *                              0  - queue is empty or throttled.
167  *                              >0 - queue is not empty.
168  *
169  */
170 static inline int qdisc_restart(struct Qdisc *q)
171 {
172         struct netdev_queue *txq;
173         struct net_device *dev;
174         spinlock_t *root_lock;
175         struct sk_buff *skb;
176
177         /* Dequeue packet */
178         skb = dequeue_skb(q);
179         if (unlikely(!skb))
180                 return 0;
181
182         root_lock = qdisc_lock(q);
183         dev = qdisc_dev(q);
184         txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
185
186         return sch_direct_xmit(skb, q, dev, txq, root_lock);
187 }
188
189 void __qdisc_run(struct Qdisc *q)
190 {
191         unsigned long start_time = jiffies;
192
193         while (qdisc_restart(q)) {
194                 /*
195                  * Postpone processing if
196                  * 1. another process needs the CPU;
197                  * 2. we've been doing it for too long.
198                  */
199                 if (need_resched() || jiffies != start_time) {
200                         __netif_schedule(q);
201                         break;
202                 }
203         }
204
205         clear_bit(__QDISC_STATE_RUNNING, &q->state);
206 }
207
208 unsigned long dev_trans_start(struct net_device *dev)
209 {
210         unsigned long val, res = dev->trans_start;
211         unsigned int i;
212
213         for (i = 0; i < dev->num_tx_queues; i++) {
214                 val = netdev_get_tx_queue(dev, i)->trans_start;
215                 if (val && time_after(val, res))
216                         res = val;
217         }
218         dev->trans_start = res;
219         return res;
220 }
221 EXPORT_SYMBOL(dev_trans_start);
222
223 static void dev_watchdog(unsigned long arg)
224 {
225         struct net_device *dev = (struct net_device *)arg;
226
227         netif_tx_lock(dev);
228         if (!qdisc_tx_is_noop(dev)) {
229                 if (netif_device_present(dev) &&
230                     netif_running(dev) &&
231                     netif_carrier_ok(dev)) {
232                         int some_queue_timedout = 0;
233                         unsigned int i;
234                         unsigned long trans_start;
235
236                         for (i = 0; i < dev->num_tx_queues; i++) {
237                                 struct netdev_queue *txq;
238
239                                 txq = netdev_get_tx_queue(dev, i);
240                                 /*
241                                  * old device drivers set dev->trans_start
242                                  */
243                                 trans_start = txq->trans_start ? : dev->trans_start;
244                                 if (netif_tx_queue_stopped(txq) &&
245                                     time_after(jiffies, (trans_start +
246                                                          dev->watchdog_timeo))) {
247                                         some_queue_timedout = 1;
248                                         break;
249                                 }
250                         }
251
252                         if (some_queue_timedout) {
253                                 char drivername[64];
254                                 WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",
255                                        dev->name, netdev_drivername(dev, drivername, 64), i);
256                                 dev->netdev_ops->ndo_tx_timeout(dev);
257                         }
258                         if (!mod_timer(&dev->watchdog_timer,
259                                        round_jiffies(jiffies +
260                                                      dev->watchdog_timeo)))
261                                 dev_hold(dev);
262                 }
263         }
264         netif_tx_unlock(dev);
265
266         dev_put(dev);
267 }
268
269 void __netdev_watchdog_up(struct net_device *dev)
270 {
271         if (dev->netdev_ops->ndo_tx_timeout) {
272                 if (dev->watchdog_timeo <= 0)
273                         dev->watchdog_timeo = 5*HZ;
274                 if (!mod_timer(&dev->watchdog_timer,
275                                round_jiffies(jiffies + dev->watchdog_timeo)))
276                         dev_hold(dev);
277         }
278 }
279
280 static void dev_watchdog_up(struct net_device *dev)
281 {
282         __netdev_watchdog_up(dev);
283 }
284
285 static void dev_watchdog_down(struct net_device *dev)
286 {
287         netif_tx_lock_bh(dev);
288         if (del_timer(&dev->watchdog_timer))
289                 dev_put(dev);
290         netif_tx_unlock_bh(dev);
291 }
292
293 /**
294  *      netif_carrier_on - set carrier
295  *      @dev: network device
296  *
297  * Device has detected that carrier.
298  */
299 void netif_carrier_on(struct net_device *dev)
300 {
301         if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
302                 if (dev->reg_state == NETREG_UNINITIALIZED)
303                         return;
304                 linkwatch_fire_event(dev);
305                 if (netif_running(dev))
306                         __netdev_watchdog_up(dev);
307         }
308 }
309 EXPORT_SYMBOL(netif_carrier_on);
310
311 /**
312  *      netif_carrier_off - clear carrier
313  *      @dev: network device
314  *
315  * Device has detected loss of carrier.
316  */
317 void netif_carrier_off(struct net_device *dev)
318 {
319         if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
320                 if (dev->reg_state == NETREG_UNINITIALIZED)
321                         return;
322                 linkwatch_fire_event(dev);
323         }
324 }
325 EXPORT_SYMBOL(netif_carrier_off);
326
327 /* "NOOP" scheduler: the best scheduler, recommended for all interfaces
328    under all circumstances. It is difficult to invent anything faster or
329    cheaper.
330  */
331
332 static int noop_enqueue(struct sk_buff *skb, struct Qdisc * qdisc)
333 {
334         kfree_skb(skb);
335         return NET_XMIT_CN;
336 }
337
338 static struct sk_buff *noop_dequeue(struct Qdisc * qdisc)
339 {
340         return NULL;
341 }
342
343 struct Qdisc_ops noop_qdisc_ops __read_mostly = {
344         .id             =       "noop",
345         .priv_size      =       0,
346         .enqueue        =       noop_enqueue,
347         .dequeue        =       noop_dequeue,
348         .peek           =       noop_dequeue,
349         .owner          =       THIS_MODULE,
350 };
351
352 static struct netdev_queue noop_netdev_queue = {
353         .qdisc          =       &noop_qdisc,
354         .qdisc_sleeping =       &noop_qdisc,
355 };
356
357 struct Qdisc noop_qdisc = {
358         .enqueue        =       noop_enqueue,
359         .dequeue        =       noop_dequeue,
360         .flags          =       TCQ_F_BUILTIN,
361         .ops            =       &noop_qdisc_ops,
362         .list           =       LIST_HEAD_INIT(noop_qdisc.list),
363         .q.lock         =       __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
364         .dev_queue      =       &noop_netdev_queue,
365 };
366 EXPORT_SYMBOL(noop_qdisc);
367
368 static struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
369         .id             =       "noqueue",
370         .priv_size      =       0,
371         .enqueue        =       noop_enqueue,
372         .dequeue        =       noop_dequeue,
373         .peek           =       noop_dequeue,
374         .owner          =       THIS_MODULE,
375 };
376
377 static struct Qdisc noqueue_qdisc;
378 static struct netdev_queue noqueue_netdev_queue = {
379         .qdisc          =       &noqueue_qdisc,
380         .qdisc_sleeping =       &noqueue_qdisc,
381 };
382
383 static struct Qdisc noqueue_qdisc = {
384         .enqueue        =       NULL,
385         .dequeue        =       noop_dequeue,
386         .flags          =       TCQ_F_BUILTIN,
387         .ops            =       &noqueue_qdisc_ops,
388         .list           =       LIST_HEAD_INIT(noqueue_qdisc.list),
389         .q.lock         =       __SPIN_LOCK_UNLOCKED(noqueue_qdisc.q.lock),
390         .dev_queue      =       &noqueue_netdev_queue,
391 };
392
393
394 static const u8 prio2band[TC_PRIO_MAX+1] =
395         { 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1 };
396
397 /* 3-band FIFO queue: old style, but should be a bit faster than
398    generic prio+fifo combination.
399  */
400
401 #define PFIFO_FAST_BANDS 3
402
403 /*
404  * Private data for a pfifo_fast scheduler containing:
405  *      - queues for the three band
406  *      - bitmap indicating which of the bands contain skbs
407  */
408 struct pfifo_fast_priv {
409         u32 bitmap;
410         struct sk_buff_head q[PFIFO_FAST_BANDS];
411 };
412
413 /*
414  * Convert a bitmap to the first band number where an skb is queued, where:
415  *      bitmap=0 means there are no skbs on any band.
416  *      bitmap=1 means there is an skb on band 0.
417  *      bitmap=7 means there are skbs on all 3 bands, etc.
418  */
419 static const int bitmap2band[] = {-1, 0, 1, 0, 2, 0, 1, 0};
420
421 static inline struct sk_buff_head *band2list(struct pfifo_fast_priv *priv,
422                                              int band)
423 {
424         return priv->q + band;
425 }
426
427 static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc* qdisc)
428 {
429         if (skb_queue_len(&qdisc->q) < qdisc_dev(qdisc)->tx_queue_len) {
430                 int band = prio2band[skb->priority & TC_PRIO_MAX];
431                 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
432                 struct sk_buff_head *list = band2list(priv, band);
433
434                 priv->bitmap |= (1 << band);
435                 qdisc->q.qlen++;
436                 return __qdisc_enqueue_tail(skb, qdisc, list);
437         }
438
439         return qdisc_drop(skb, qdisc);
440 }
441
442 static struct sk_buff *pfifo_fast_dequeue(struct Qdisc* qdisc)
443 {
444         struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
445         int band = bitmap2band[priv->bitmap];
446
447         if (likely(band >= 0)) {
448                 struct sk_buff_head *list = band2list(priv, band);
449                 struct sk_buff *skb = __qdisc_dequeue_head(qdisc, list);
450
451                 qdisc->q.qlen--;
452                 if (skb_queue_empty(list))
453                         priv->bitmap &= ~(1 << band);
454
455                 return skb;
456         }
457
458         return NULL;
459 }
460
461 static struct sk_buff *pfifo_fast_peek(struct Qdisc* qdisc)
462 {
463         struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
464         int band = bitmap2band[priv->bitmap];
465
466         if (band >= 0) {
467                 struct sk_buff_head *list = band2list(priv, band);
468
469                 return skb_peek(list);
470         }
471
472         return NULL;
473 }
474
475 static void pfifo_fast_reset(struct Qdisc* qdisc)
476 {
477         int prio;
478         struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
479
480         for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
481                 __qdisc_reset_queue(qdisc, band2list(priv, prio));
482
483         priv->bitmap = 0;
484         qdisc->qstats.backlog = 0;
485         qdisc->q.qlen = 0;
486 }
487
488 static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
489 {
490         struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
491
492         memcpy(&opt.priomap, prio2band, TC_PRIO_MAX+1);
493         NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
494         return skb->len;
495
496 nla_put_failure:
497         return -1;
498 }
499
500 static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt)
501 {
502         int prio;
503         struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
504
505         for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
506                 skb_queue_head_init(band2list(priv, prio));
507
508         return 0;
509 }
510
511 struct Qdisc_ops pfifo_fast_ops __read_mostly = {
512         .id             =       "pfifo_fast",
513         .priv_size      =       sizeof(struct pfifo_fast_priv),
514         .enqueue        =       pfifo_fast_enqueue,
515         .dequeue        =       pfifo_fast_dequeue,
516         .peek           =       pfifo_fast_peek,
517         .init           =       pfifo_fast_init,
518         .reset          =       pfifo_fast_reset,
519         .dump           =       pfifo_fast_dump,
520         .owner          =       THIS_MODULE,
521 };
522
523 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
524                           struct Qdisc_ops *ops)
525 {
526         void *p;
527         struct Qdisc *sch;
528         unsigned int size;
529         int err = -ENOBUFS;
530
531         /* ensure that the Qdisc and the private data are 32-byte aligned */
532         size = QDISC_ALIGN(sizeof(*sch));
533         size += ops->priv_size + (QDISC_ALIGNTO - 1);
534
535         p = kzalloc(size, GFP_KERNEL);
536         if (!p)
537                 goto errout;
538         sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
539         sch->padded = (char *) sch - (char *) p;
540
541         INIT_LIST_HEAD(&sch->list);
542         skb_queue_head_init(&sch->q);
543         sch->ops = ops;
544         sch->enqueue = ops->enqueue;
545         sch->dequeue = ops->dequeue;
546         sch->dev_queue = dev_queue;
547         dev_hold(qdisc_dev(sch));
548         atomic_set(&sch->refcnt, 1);
549
550         return sch;
551 errout:
552         return ERR_PTR(err);
553 }
554
555 struct Qdisc * qdisc_create_dflt(struct net_device *dev,
556                                  struct netdev_queue *dev_queue,
557                                  struct Qdisc_ops *ops,
558                                  unsigned int parentid)
559 {
560         struct Qdisc *sch;
561
562         sch = qdisc_alloc(dev_queue, ops);
563         if (IS_ERR(sch))
564                 goto errout;
565         sch->parent = parentid;
566
567         if (!ops->init || ops->init(sch, NULL) == 0)
568                 return sch;
569
570         qdisc_destroy(sch);
571 errout:
572         return NULL;
573 }
574 EXPORT_SYMBOL(qdisc_create_dflt);
575
576 /* Under qdisc_lock(qdisc) and BH! */
577
578 void qdisc_reset(struct Qdisc *qdisc)
579 {
580         const struct Qdisc_ops *ops = qdisc->ops;
581
582         if (ops->reset)
583                 ops->reset(qdisc);
584
585         if (qdisc->gso_skb) {
586                 kfree_skb(qdisc->gso_skb);
587                 qdisc->gso_skb = NULL;
588                 qdisc->q.qlen = 0;
589         }
590 }
591 EXPORT_SYMBOL(qdisc_reset);
592
593 void qdisc_destroy(struct Qdisc *qdisc)
594 {
595         const struct Qdisc_ops  *ops = qdisc->ops;
596
597         if (qdisc->flags & TCQ_F_BUILTIN ||
598             !atomic_dec_and_test(&qdisc->refcnt))
599                 return;
600
601 #ifdef CONFIG_NET_SCHED
602         qdisc_list_del(qdisc);
603
604         qdisc_put_stab(qdisc->stab);
605 #endif
606         gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est);
607         if (ops->reset)
608                 ops->reset(qdisc);
609         if (ops->destroy)
610                 ops->destroy(qdisc);
611
612         module_put(ops->owner);
613         dev_put(qdisc_dev(qdisc));
614
615         kfree_skb(qdisc->gso_skb);
616         kfree((char *) qdisc - qdisc->padded);
617 }
618 EXPORT_SYMBOL(qdisc_destroy);
619
620 /* Attach toplevel qdisc to device queue. */
621 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
622                               struct Qdisc *qdisc)
623 {
624         struct Qdisc *oqdisc = dev_queue->qdisc_sleeping;
625         spinlock_t *root_lock;
626
627         root_lock = qdisc_lock(oqdisc);
628         spin_lock_bh(root_lock);
629
630         /* Prune old scheduler */
631         if (oqdisc && atomic_read(&oqdisc->refcnt) <= 1)
632                 qdisc_reset(oqdisc);
633
634         /* ... and graft new one */
635         if (qdisc == NULL)
636                 qdisc = &noop_qdisc;
637         dev_queue->qdisc_sleeping = qdisc;
638         rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
639
640         spin_unlock_bh(root_lock);
641
642         return oqdisc;
643 }
644
645 static void attach_one_default_qdisc(struct net_device *dev,
646                                      struct netdev_queue *dev_queue,
647                                      void *_unused)
648 {
649         struct Qdisc *qdisc;
650
651         if (dev->tx_queue_len) {
652                 qdisc = qdisc_create_dflt(dev, dev_queue,
653                                           &pfifo_fast_ops, TC_H_ROOT);
654                 if (!qdisc) {
655                         printk(KERN_INFO "%s: activation failed\n", dev->name);
656                         return;
657                 }
658
659                 /* Can by-pass the queue discipline for default qdisc */
660                 qdisc->flags |= TCQ_F_CAN_BYPASS;
661         } else {
662                 qdisc =  &noqueue_qdisc;
663         }
664         dev_queue->qdisc_sleeping = qdisc;
665 }
666
667 static void attach_default_qdiscs(struct net_device *dev)
668 {
669         struct netdev_queue *txq;
670         struct Qdisc *qdisc;
671
672         txq = netdev_get_tx_queue(dev, 0);
673
674         if (!netif_is_multiqueue(dev) || dev->tx_queue_len == 0) {
675                 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
676                 dev->qdisc = txq->qdisc_sleeping;
677                 atomic_inc(&dev->qdisc->refcnt);
678         } else {
679                 qdisc = qdisc_create_dflt(dev, txq, &mq_qdisc_ops, TC_H_ROOT);
680                 if (qdisc) {
681                         qdisc->ops->attach(qdisc);
682                         dev->qdisc = qdisc;
683                 }
684         }
685 }
686
687 static void transition_one_qdisc(struct net_device *dev,
688                                  struct netdev_queue *dev_queue,
689                                  void *_need_watchdog)
690 {
691         struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
692         int *need_watchdog_p = _need_watchdog;
693
694         if (!(new_qdisc->flags & TCQ_F_BUILTIN))
695                 clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
696
697         rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
698         if (need_watchdog_p && new_qdisc != &noqueue_qdisc) {
699                 dev_queue->trans_start = 0;
700                 *need_watchdog_p = 1;
701         }
702 }
703
704 void dev_activate(struct net_device *dev)
705 {
706         int need_watchdog;
707
708         /* No queueing discipline is attached to device;
709            create default one i.e. pfifo_fast for devices,
710            which need queueing and noqueue_qdisc for
711            virtual interfaces
712          */
713
714         if (dev->qdisc == &noop_qdisc)
715                 attach_default_qdiscs(dev);
716
717         if (!netif_carrier_ok(dev))
718                 /* Delay activation until next carrier-on event */
719                 return;
720
721         need_watchdog = 0;
722         netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
723         transition_one_qdisc(dev, &dev->rx_queue, NULL);
724
725         if (need_watchdog) {
726                 dev->trans_start = jiffies;
727                 dev_watchdog_up(dev);
728         }
729 }
730
731 static void dev_deactivate_queue(struct net_device *dev,
732                                  struct netdev_queue *dev_queue,
733                                  void *_qdisc_default)
734 {
735         struct Qdisc *qdisc_default = _qdisc_default;
736         struct Qdisc *qdisc;
737
738         qdisc = dev_queue->qdisc;
739         if (qdisc) {
740                 spin_lock_bh(qdisc_lock(qdisc));
741
742                 if (!(qdisc->flags & TCQ_F_BUILTIN))
743                         set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
744
745                 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
746                 qdisc_reset(qdisc);
747
748                 spin_unlock_bh(qdisc_lock(qdisc));
749         }
750 }
751
752 static bool some_qdisc_is_busy(struct net_device *dev)
753 {
754         unsigned int i;
755
756         for (i = 0; i < dev->num_tx_queues; i++) {
757                 struct netdev_queue *dev_queue;
758                 spinlock_t *root_lock;
759                 struct Qdisc *q;
760                 int val;
761
762                 dev_queue = netdev_get_tx_queue(dev, i);
763                 q = dev_queue->qdisc_sleeping;
764                 root_lock = qdisc_lock(q);
765
766                 spin_lock_bh(root_lock);
767
768                 val = (test_bit(__QDISC_STATE_RUNNING, &q->state) ||
769                        test_bit(__QDISC_STATE_SCHED, &q->state));
770
771                 spin_unlock_bh(root_lock);
772
773                 if (val)
774                         return true;
775         }
776         return false;
777 }
778
779 void dev_deactivate(struct net_device *dev)
780 {
781         netdev_for_each_tx_queue(dev, dev_deactivate_queue, &noop_qdisc);
782         dev_deactivate_queue(dev, &dev->rx_queue, &noop_qdisc);
783
784         dev_watchdog_down(dev);
785
786         /* Wait for outstanding qdisc-less dev_queue_xmit calls. */
787         synchronize_rcu();
788
789         /* Wait for outstanding qdisc_run calls. */
790         while (some_qdisc_is_busy(dev))
791                 yield();
792 }
793
794 static void dev_init_scheduler_queue(struct net_device *dev,
795                                      struct netdev_queue *dev_queue,
796                                      void *_qdisc)
797 {
798         struct Qdisc *qdisc = _qdisc;
799
800         dev_queue->qdisc = qdisc;
801         dev_queue->qdisc_sleeping = qdisc;
802 }
803
804 void dev_init_scheduler(struct net_device *dev)
805 {
806         dev->qdisc = &noop_qdisc;
807         netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
808         dev_init_scheduler_queue(dev, &dev->rx_queue, &noop_qdisc);
809
810         setup_timer(&dev->watchdog_timer, dev_watchdog, (unsigned long)dev);
811 }
812
813 static void shutdown_scheduler_queue(struct net_device *dev,
814                                      struct netdev_queue *dev_queue,
815                                      void *_qdisc_default)
816 {
817         struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
818         struct Qdisc *qdisc_default = _qdisc_default;
819
820         if (qdisc) {
821                 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
822                 dev_queue->qdisc_sleeping = qdisc_default;
823
824                 qdisc_destroy(qdisc);
825         }
826 }
827
828 void dev_shutdown(struct net_device *dev)
829 {
830         netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
831         shutdown_scheduler_queue(dev, &dev->rx_queue, &noop_qdisc);
832         qdisc_destroy(dev->qdisc);
833         dev->qdisc = &noop_qdisc;
834
835         WARN_ON(timer_pending(&dev->watchdog_timer));
836 }