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Commit | Line | Data |
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1da177e4 LT |
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 | ||
1da177e4 | 14 | #include <linux/bitops.h> |
1da177e4 LT |
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> | |
1da177e4 | 20 | #include <linux/errno.h> |
1da177e4 LT |
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> | |
1da177e4 LT |
27 | #include <net/pkt_sched.h> |
28 | ||
29 | /* Main transmission queue. */ | |
30 | ||
0463d4ae | 31 | /* Modifications to data participating in scheduling must be protected with |
c7e4f3bb | 32 | * qdisc_root_lock(qdisc) spinlock. |
0463d4ae PM |
33 | * |
34 | * The idea is the following: | |
c7e4f3bb DM |
35 | * - enqueue, dequeue are serialized via qdisc root lock |
36 | * - ingress filtering is also serialized via qdisc root lock | |
0463d4ae | 37 | * - updates to tree and tree walking are only done under the rtnl mutex. |
1da177e4 | 38 | */ |
1da177e4 | 39 | |
c716a81a JHS |
40 | static inline int qdisc_qlen(struct Qdisc *q) |
41 | { | |
c716a81a JHS |
42 | return q->q.qlen; |
43 | } | |
44 | ||
37437bb2 | 45 | static inline int dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q) |
c716a81a | 46 | { |
c716a81a | 47 | if (unlikely(skb->next)) |
d3b753db | 48 | q->gso_skb = skb; |
c716a81a JHS |
49 | else |
50 | q->ops->requeue(skb, q); | |
6c1361a6 | 51 | |
37437bb2 | 52 | __netif_schedule(q); |
c716a81a JHS |
53 | return 0; |
54 | } | |
55 | ||
d3b753db | 56 | static inline struct sk_buff *dequeue_skb(struct Qdisc *q) |
c716a81a | 57 | { |
6c1361a6 | 58 | struct sk_buff *skb; |
c716a81a | 59 | |
d3b753db DM |
60 | if ((skb = q->gso_skb)) |
61 | q->gso_skb = NULL; | |
c716a81a JHS |
62 | else |
63 | skb = q->dequeue(q); | |
64 | ||
65 | return skb; | |
66 | } | |
67 | ||
6c1361a6 | 68 | static inline int handle_dev_cpu_collision(struct sk_buff *skb, |
970565bb | 69 | struct netdev_queue *dev_queue, |
6c1361a6 | 70 | struct Qdisc *q) |
c716a81a | 71 | { |
6c1361a6 | 72 | int ret; |
c716a81a | 73 | |
c773e847 | 74 | if (unlikely(dev_queue->xmit_lock_owner == smp_processor_id())) { |
6c1361a6 KK |
75 | /* |
76 | * Same CPU holding the lock. It may be a transient | |
77 | * configuration error, when hard_start_xmit() recurses. We | |
78 | * detect it by checking xmit owner and drop the packet when | |
79 | * deadloop is detected. Return OK to try the next skb. | |
80 | */ | |
c716a81a | 81 | kfree_skb(skb); |
6c1361a6 KK |
82 | if (net_ratelimit()) |
83 | printk(KERN_WARNING "Dead loop on netdevice %s, " | |
c773e847 | 84 | "fix it urgently!\n", dev_queue->dev->name); |
6c1361a6 KK |
85 | ret = qdisc_qlen(q); |
86 | } else { | |
87 | /* | |
88 | * Another cpu is holding lock, requeue & delay xmits for | |
89 | * some time. | |
90 | */ | |
91 | __get_cpu_var(netdev_rx_stat).cpu_collision++; | |
37437bb2 | 92 | ret = dev_requeue_skb(skb, q); |
c716a81a JHS |
93 | } |
94 | ||
6c1361a6 | 95 | return ret; |
c716a81a JHS |
96 | } |
97 | ||
10297b99 | 98 | /* |
83874000 | 99 | * NOTE: Called under qdisc_lock(q) with locally disabled BH. |
6c1361a6 | 100 | * |
e2627c8c | 101 | * __QDISC_STATE_RUNNING guarantees only one CPU can process |
83874000 DM |
102 | * this qdisc at a time. qdisc_lock(q) serializes queue accesses for |
103 | * this queue. | |
6c1361a6 KK |
104 | * |
105 | * netif_tx_lock serializes accesses to device driver. | |
106 | * | |
83874000 | 107 | * qdisc_lock(q) and netif_tx_lock are mutually exclusive, |
6c1361a6 KK |
108 | * if one is grabbed, another must be free. |
109 | * | |
110 | * Note, that this procedure can be called by a watchdog timer | |
111 | * | |
112 | * Returns to the caller: | |
113 | * 0 - queue is empty or throttled. | |
114 | * >0 - queue is not empty. | |
115 | * | |
116 | */ | |
37437bb2 | 117 | static inline int qdisc_restart(struct Qdisc *q) |
1da177e4 | 118 | { |
37437bb2 | 119 | struct netdev_queue *txq; |
5f1a485d | 120 | int ret = NETDEV_TX_BUSY; |
eb6aafe3 | 121 | struct net_device *dev; |
7698b4fc | 122 | spinlock_t *root_lock; |
eb6aafe3 | 123 | struct sk_buff *skb; |
1da177e4 | 124 | |
6c1361a6 | 125 | /* Dequeue packet */ |
d3b753db | 126 | if (unlikely((skb = dequeue_skb(q)) == NULL)) |
c716a81a | 127 | return 0; |
f6a78bfc | 128 | |
7698b4fc DM |
129 | root_lock = qdisc_root_lock(q); |
130 | ||
131 | /* And release qdisc */ | |
132 | spin_unlock(root_lock); | |
c716a81a | 133 | |
37437bb2 DM |
134 | dev = qdisc_dev(q); |
135 | txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb)); | |
eb6aafe3 | 136 | |
c773e847 | 137 | HARD_TX_LOCK(dev, txq, smp_processor_id()); |
5f1a485d | 138 | if (!netif_subqueue_stopped(dev, skb)) |
fd2ea0a7 | 139 | ret = dev_hard_start_xmit(skb, dev, txq); |
c773e847 | 140 | HARD_TX_UNLOCK(dev, txq); |
c716a81a | 141 | |
7698b4fc | 142 | spin_lock(root_lock); |
c716a81a | 143 | |
6c1361a6 KK |
144 | switch (ret) { |
145 | case NETDEV_TX_OK: | |
146 | /* Driver sent out skb successfully */ | |
147 | ret = qdisc_qlen(q); | |
148 | break; | |
149 | ||
150 | case NETDEV_TX_LOCKED: | |
151 | /* Driver try lock failed */ | |
eb6aafe3 | 152 | ret = handle_dev_cpu_collision(skb, txq, q); |
6c1361a6 KK |
153 | break; |
154 | ||
155 | default: | |
156 | /* Driver returned NETDEV_TX_BUSY - requeue skb */ | |
157 | if (unlikely (ret != NETDEV_TX_BUSY && net_ratelimit())) | |
158 | printk(KERN_WARNING "BUG %s code %d qlen %d\n", | |
159 | dev->name, ret, q->q.qlen); | |
160 | ||
37437bb2 | 161 | ret = dev_requeue_skb(skb, q); |
6c1361a6 KK |
162 | break; |
163 | } | |
c716a81a | 164 | |
37437bb2 DM |
165 | if (ret && netif_tx_queue_stopped(txq)) |
166 | ret = 0; | |
167 | ||
6c1361a6 | 168 | return ret; |
1da177e4 LT |
169 | } |
170 | ||
37437bb2 | 171 | void __qdisc_run(struct Qdisc *q) |
48d83325 | 172 | { |
2ba2506c | 173 | unsigned long start_time = jiffies; |
2ba2506c | 174 | |
37437bb2 | 175 | while (qdisc_restart(q)) { |
2ba2506c HX |
176 | /* |
177 | * Postpone processing if | |
178 | * 1. another process needs the CPU; | |
179 | * 2. we've been doing it for too long. | |
180 | */ | |
181 | if (need_resched() || jiffies != start_time) { | |
37437bb2 | 182 | __netif_schedule(q); |
d90df3ad | 183 | break; |
2ba2506c HX |
184 | } |
185 | } | |
48d83325 | 186 | |
e2627c8c | 187 | clear_bit(__QDISC_STATE_RUNNING, &q->state); |
48d83325 HX |
188 | } |
189 | ||
1da177e4 LT |
190 | static void dev_watchdog(unsigned long arg) |
191 | { | |
192 | struct net_device *dev = (struct net_device *)arg; | |
193 | ||
932ff279 | 194 | netif_tx_lock(dev); |
e8a0464c | 195 | if (!qdisc_tx_is_noop(dev)) { |
1da177e4 LT |
196 | if (netif_device_present(dev) && |
197 | netif_running(dev) && | |
198 | netif_carrier_ok(dev)) { | |
e8a0464c DM |
199 | int some_queue_stopped = 0; |
200 | unsigned int i; | |
201 | ||
202 | for (i = 0; i < dev->num_tx_queues; i++) { | |
203 | struct netdev_queue *txq; | |
204 | ||
205 | txq = netdev_get_tx_queue(dev, i); | |
206 | if (netif_tx_queue_stopped(txq)) { | |
207 | some_queue_stopped = 1; | |
208 | break; | |
209 | } | |
210 | } | |
338f7566 | 211 | |
e8a0464c DM |
212 | if (some_queue_stopped && |
213 | time_after(jiffies, (dev->trans_start + | |
214 | dev->watchdog_timeo))) { | |
215 | printk(KERN_INFO "NETDEV WATCHDOG: %s: " | |
216 | "transmit timed out\n", | |
338f7566 | 217 | dev->name); |
1da177e4 | 218 | dev->tx_timeout(dev); |
b4192bbd | 219 | WARN_ON_ONCE(1); |
1da177e4 | 220 | } |
e8a0464c DM |
221 | if (!mod_timer(&dev->watchdog_timer, |
222 | round_jiffies(jiffies + | |
223 | dev->watchdog_timeo))) | |
1da177e4 LT |
224 | dev_hold(dev); |
225 | } | |
226 | } | |
932ff279 | 227 | netif_tx_unlock(dev); |
1da177e4 LT |
228 | |
229 | dev_put(dev); | |
230 | } | |
231 | ||
1da177e4 LT |
232 | void __netdev_watchdog_up(struct net_device *dev) |
233 | { | |
234 | if (dev->tx_timeout) { | |
235 | if (dev->watchdog_timeo <= 0) | |
236 | dev->watchdog_timeo = 5*HZ; | |
60468d5b VP |
237 | if (!mod_timer(&dev->watchdog_timer, |
238 | round_jiffies(jiffies + dev->watchdog_timeo))) | |
1da177e4 LT |
239 | dev_hold(dev); |
240 | } | |
241 | } | |
242 | ||
243 | static void dev_watchdog_up(struct net_device *dev) | |
244 | { | |
1da177e4 | 245 | __netdev_watchdog_up(dev); |
1da177e4 LT |
246 | } |
247 | ||
248 | static void dev_watchdog_down(struct net_device *dev) | |
249 | { | |
932ff279 | 250 | netif_tx_lock_bh(dev); |
1da177e4 | 251 | if (del_timer(&dev->watchdog_timer)) |
15333061 | 252 | dev_put(dev); |
932ff279 | 253 | netif_tx_unlock_bh(dev); |
1da177e4 LT |
254 | } |
255 | ||
bea3348e SH |
256 | /** |
257 | * netif_carrier_on - set carrier | |
258 | * @dev: network device | |
259 | * | |
260 | * Device has detected that carrier. | |
261 | */ | |
0a242efc DV |
262 | void netif_carrier_on(struct net_device *dev) |
263 | { | |
bfaae0f0 | 264 | if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) { |
0a242efc | 265 | linkwatch_fire_event(dev); |
bfaae0f0 JG |
266 | if (netif_running(dev)) |
267 | __netdev_watchdog_up(dev); | |
268 | } | |
0a242efc | 269 | } |
62e3ba1b | 270 | EXPORT_SYMBOL(netif_carrier_on); |
0a242efc | 271 | |
bea3348e SH |
272 | /** |
273 | * netif_carrier_off - clear carrier | |
274 | * @dev: network device | |
275 | * | |
276 | * Device has detected loss of carrier. | |
277 | */ | |
0a242efc DV |
278 | void netif_carrier_off(struct net_device *dev) |
279 | { | |
280 | if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) | |
281 | linkwatch_fire_event(dev); | |
282 | } | |
62e3ba1b | 283 | EXPORT_SYMBOL(netif_carrier_off); |
0a242efc | 284 | |
1da177e4 LT |
285 | /* "NOOP" scheduler: the best scheduler, recommended for all interfaces |
286 | under all circumstances. It is difficult to invent anything faster or | |
287 | cheaper. | |
288 | */ | |
289 | ||
94df109a | 290 | static int noop_enqueue(struct sk_buff *skb, struct Qdisc * qdisc) |
1da177e4 LT |
291 | { |
292 | kfree_skb(skb); | |
293 | return NET_XMIT_CN; | |
294 | } | |
295 | ||
94df109a | 296 | static struct sk_buff *noop_dequeue(struct Qdisc * qdisc) |
1da177e4 LT |
297 | { |
298 | return NULL; | |
299 | } | |
300 | ||
94df109a | 301 | static int noop_requeue(struct sk_buff *skb, struct Qdisc* qdisc) |
1da177e4 LT |
302 | { |
303 | if (net_ratelimit()) | |
94df109a TG |
304 | printk(KERN_DEBUG "%s deferred output. It is buggy.\n", |
305 | skb->dev->name); | |
1da177e4 LT |
306 | kfree_skb(skb); |
307 | return NET_XMIT_CN; | |
308 | } | |
309 | ||
20fea08b | 310 | struct Qdisc_ops noop_qdisc_ops __read_mostly = { |
1da177e4 LT |
311 | .id = "noop", |
312 | .priv_size = 0, | |
313 | .enqueue = noop_enqueue, | |
314 | .dequeue = noop_dequeue, | |
315 | .requeue = noop_requeue, | |
316 | .owner = THIS_MODULE, | |
317 | }; | |
318 | ||
7698b4fc | 319 | static struct netdev_queue noop_netdev_queue = { |
7698b4fc DM |
320 | .qdisc = &noop_qdisc, |
321 | }; | |
322 | ||
1da177e4 LT |
323 | struct Qdisc noop_qdisc = { |
324 | .enqueue = noop_enqueue, | |
325 | .dequeue = noop_dequeue, | |
326 | .flags = TCQ_F_BUILTIN, | |
10297b99 | 327 | .ops = &noop_qdisc_ops, |
1da177e4 | 328 | .list = LIST_HEAD_INIT(noop_qdisc.list), |
83874000 | 329 | .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock), |
7698b4fc | 330 | .dev_queue = &noop_netdev_queue, |
1da177e4 | 331 | }; |
62e3ba1b | 332 | EXPORT_SYMBOL(noop_qdisc); |
1da177e4 | 333 | |
20fea08b | 334 | static struct Qdisc_ops noqueue_qdisc_ops __read_mostly = { |
1da177e4 LT |
335 | .id = "noqueue", |
336 | .priv_size = 0, | |
337 | .enqueue = noop_enqueue, | |
338 | .dequeue = noop_dequeue, | |
339 | .requeue = noop_requeue, | |
340 | .owner = THIS_MODULE, | |
341 | }; | |
342 | ||
30ee42be DM |
343 | static struct Qdisc noqueue_qdisc; |
344 | static struct netdev_queue noqueue_netdev_queue = { | |
345 | .qdisc = &noqueue_qdisc, | |
346 | }; | |
347 | ||
1da177e4 LT |
348 | static struct Qdisc noqueue_qdisc = { |
349 | .enqueue = NULL, | |
350 | .dequeue = noop_dequeue, | |
351 | .flags = TCQ_F_BUILTIN, | |
352 | .ops = &noqueue_qdisc_ops, | |
353 | .list = LIST_HEAD_INIT(noqueue_qdisc.list), | |
30ee42be DM |
354 | .q.lock = __SPIN_LOCK_UNLOCKED(noqueue_qdisc.q.lock), |
355 | .dev_queue = &noqueue_netdev_queue, | |
1da177e4 LT |
356 | }; |
357 | ||
358 | ||
a0c80b80 | 359 | static int fifo_fast_enqueue(struct sk_buff *skb, struct Qdisc* qdisc) |
321090e7 | 360 | { |
a0c80b80 | 361 | struct sk_buff_head *list = &qdisc->q; |
1da177e4 | 362 | |
a0c80b80 | 363 | if (skb_queue_len(list) < qdisc_dev(qdisc)->tx_queue_len) |
821d24ae | 364 | return __qdisc_enqueue_tail(skb, qdisc, list); |
821d24ae TG |
365 | |
366 | return qdisc_drop(skb, qdisc); | |
1da177e4 LT |
367 | } |
368 | ||
a0c80b80 | 369 | static struct sk_buff *fifo_fast_dequeue(struct Qdisc* qdisc) |
1da177e4 | 370 | { |
a0c80b80 | 371 | struct sk_buff_head *list = &qdisc->q; |
1da177e4 | 372 | |
a0c80b80 DM |
373 | if (!skb_queue_empty(list)) |
374 | return __qdisc_dequeue_head(qdisc, list); | |
f87a9c3d | 375 | |
1da177e4 LT |
376 | return NULL; |
377 | } | |
378 | ||
a0c80b80 | 379 | static int fifo_fast_requeue(struct sk_buff *skb, struct Qdisc* qdisc) |
1da177e4 | 380 | { |
a0c80b80 | 381 | return __qdisc_requeue(skb, qdisc, &qdisc->q); |
1da177e4 LT |
382 | } |
383 | ||
a0c80b80 | 384 | static void fifo_fast_reset(struct Qdisc* qdisc) |
1da177e4 | 385 | { |
a0c80b80 | 386 | __qdisc_reset_queue(qdisc, &qdisc->q); |
821d24ae | 387 | qdisc->qstats.backlog = 0; |
1da177e4 LT |
388 | } |
389 | ||
a0c80b80 DM |
390 | static struct Qdisc_ops fifo_fast_ops __read_mostly = { |
391 | .id = "fifo_fast", | |
392 | .priv_size = 0, | |
393 | .enqueue = fifo_fast_enqueue, | |
394 | .dequeue = fifo_fast_dequeue, | |
395 | .requeue = fifo_fast_requeue, | |
396 | .reset = fifo_fast_reset, | |
1da177e4 LT |
397 | .owner = THIS_MODULE, |
398 | }; | |
399 | ||
5ce2d488 | 400 | struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue, |
bb949fbd | 401 | struct Qdisc_ops *ops) |
1da177e4 LT |
402 | { |
403 | void *p; | |
404 | struct Qdisc *sch; | |
3d54b82f TG |
405 | unsigned int size; |
406 | int err = -ENOBUFS; | |
1da177e4 LT |
407 | |
408 | /* ensure that the Qdisc and the private data are 32-byte aligned */ | |
3d54b82f TG |
409 | size = QDISC_ALIGN(sizeof(*sch)); |
410 | size += ops->priv_size + (QDISC_ALIGNTO - 1); | |
1da177e4 | 411 | |
0da974f4 | 412 | p = kzalloc(size, GFP_KERNEL); |
1da177e4 | 413 | if (!p) |
3d54b82f | 414 | goto errout; |
3d54b82f TG |
415 | sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p); |
416 | sch->padded = (char *) sch - (char *) p; | |
1da177e4 LT |
417 | |
418 | INIT_LIST_HEAD(&sch->list); | |
419 | skb_queue_head_init(&sch->q); | |
420 | sch->ops = ops; | |
421 | sch->enqueue = ops->enqueue; | |
422 | sch->dequeue = ops->dequeue; | |
bb949fbd | 423 | sch->dev_queue = dev_queue; |
5ce2d488 | 424 | dev_hold(qdisc_dev(sch)); |
1da177e4 | 425 | atomic_set(&sch->refcnt, 1); |
3d54b82f TG |
426 | |
427 | return sch; | |
428 | errout: | |
01e123d7 | 429 | return ERR_PTR(err); |
3d54b82f TG |
430 | } |
431 | ||
bb949fbd DM |
432 | struct Qdisc * qdisc_create_dflt(struct net_device *dev, |
433 | struct netdev_queue *dev_queue, | |
434 | struct Qdisc_ops *ops, | |
9f9afec4 | 435 | unsigned int parentid) |
3d54b82f TG |
436 | { |
437 | struct Qdisc *sch; | |
10297b99 | 438 | |
5ce2d488 | 439 | sch = qdisc_alloc(dev_queue, ops); |
3d54b82f TG |
440 | if (IS_ERR(sch)) |
441 | goto errout; | |
9f9afec4 | 442 | sch->parent = parentid; |
3d54b82f | 443 | |
1da177e4 LT |
444 | if (!ops->init || ops->init(sch, NULL) == 0) |
445 | return sch; | |
446 | ||
0fbbeb1b | 447 | qdisc_destroy(sch); |
3d54b82f | 448 | errout: |
1da177e4 LT |
449 | return NULL; |
450 | } | |
62e3ba1b | 451 | EXPORT_SYMBOL(qdisc_create_dflt); |
1da177e4 | 452 | |
83874000 | 453 | /* Under qdisc_root_lock(qdisc) and BH! */ |
1da177e4 LT |
454 | |
455 | void qdisc_reset(struct Qdisc *qdisc) | |
456 | { | |
20fea08b | 457 | const struct Qdisc_ops *ops = qdisc->ops; |
1da177e4 LT |
458 | |
459 | if (ops->reset) | |
460 | ops->reset(qdisc); | |
461 | } | |
62e3ba1b | 462 | EXPORT_SYMBOL(qdisc_reset); |
1da177e4 | 463 | |
10297b99 | 464 | /* this is the rcu callback function to clean up a qdisc when there |
1da177e4 LT |
465 | * are no further references to it */ |
466 | ||
467 | static void __qdisc_destroy(struct rcu_head *head) | |
468 | { | |
469 | struct Qdisc *qdisc = container_of(head, struct Qdisc, q_rcu); | |
8a34c5dc DM |
470 | const struct Qdisc_ops *ops = qdisc->ops; |
471 | ||
472 | gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est); | |
473 | if (ops->reset) | |
474 | ops->reset(qdisc); | |
475 | if (ops->destroy) | |
476 | ops->destroy(qdisc); | |
477 | ||
478 | module_put(ops->owner); | |
479 | dev_put(qdisc_dev(qdisc)); | |
480 | ||
83874000 DM |
481 | kfree_skb(qdisc->gso_skb); |
482 | ||
1da177e4 LT |
483 | kfree((char *) qdisc - qdisc->padded); |
484 | } | |
485 | ||
83874000 | 486 | /* Under qdisc_root_lock(qdisc) and BH! */ |
1da177e4 LT |
487 | |
488 | void qdisc_destroy(struct Qdisc *qdisc) | |
489 | { | |
1da177e4 | 490 | if (qdisc->flags & TCQ_F_BUILTIN || |
85670cc1 | 491 | !atomic_dec_and_test(&qdisc->refcnt)) |
1da177e4 LT |
492 | return; |
493 | ||
30723673 DM |
494 | if (qdisc->parent) |
495 | list_del(&qdisc->list); | |
1da177e4 LT |
496 | |
497 | call_rcu(&qdisc->q_rcu, __qdisc_destroy); | |
498 | } | |
62e3ba1b | 499 | EXPORT_SYMBOL(qdisc_destroy); |
1da177e4 | 500 | |
e8a0464c DM |
501 | static bool dev_all_qdisc_sleeping_noop(struct net_device *dev) |
502 | { | |
503 | unsigned int i; | |
504 | ||
505 | for (i = 0; i < dev->num_tx_queues; i++) { | |
506 | struct netdev_queue *txq = netdev_get_tx_queue(dev, i); | |
507 | ||
508 | if (txq->qdisc_sleeping != &noop_qdisc) | |
509 | return false; | |
510 | } | |
511 | return true; | |
512 | } | |
513 | ||
514 | static void attach_one_default_qdisc(struct net_device *dev, | |
515 | struct netdev_queue *dev_queue, | |
516 | void *_unused) | |
517 | { | |
518 | struct Qdisc *qdisc; | |
519 | ||
520 | if (dev->tx_queue_len) { | |
521 | qdisc = qdisc_create_dflt(dev, dev_queue, | |
a0c80b80 | 522 | &fifo_fast_ops, TC_H_ROOT); |
e8a0464c DM |
523 | if (!qdisc) { |
524 | printk(KERN_INFO "%s: activation failed\n", dev->name); | |
525 | return; | |
526 | } | |
e8a0464c DM |
527 | } else { |
528 | qdisc = &noqueue_qdisc; | |
529 | } | |
530 | dev_queue->qdisc_sleeping = qdisc; | |
531 | } | |
532 | ||
533 | static void transition_one_qdisc(struct net_device *dev, | |
534 | struct netdev_queue *dev_queue, | |
535 | void *_need_watchdog) | |
536 | { | |
83874000 | 537 | struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping; |
e8a0464c DM |
538 | int *need_watchdog_p = _need_watchdog; |
539 | ||
83874000 DM |
540 | rcu_assign_pointer(dev_queue->qdisc, new_qdisc); |
541 | if (new_qdisc != &noqueue_qdisc) | |
e8a0464c | 542 | *need_watchdog_p = 1; |
e8a0464c DM |
543 | } |
544 | ||
1da177e4 LT |
545 | void dev_activate(struct net_device *dev) |
546 | { | |
e8a0464c | 547 | int need_watchdog; |
b0e1e646 | 548 | |
1da177e4 | 549 | /* No queueing discipline is attached to device; |
a0c80b80 DM |
550 | * create default one i.e. fifo_fast for devices, |
551 | * which need queueing and noqueue_qdisc for | |
552 | * virtual interfaces. | |
1da177e4 LT |
553 | */ |
554 | ||
e8a0464c DM |
555 | if (dev_all_qdisc_sleeping_noop(dev)) |
556 | netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL); | |
1da177e4 | 557 | |
cacaddf5 TC |
558 | if (!netif_carrier_ok(dev)) |
559 | /* Delay activation until next carrier-on event */ | |
560 | return; | |
561 | ||
e8a0464c DM |
562 | need_watchdog = 0; |
563 | netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog); | |
564 | ||
565 | if (need_watchdog) { | |
1da177e4 LT |
566 | dev->trans_start = jiffies; |
567 | dev_watchdog_up(dev); | |
568 | } | |
b0e1e646 DM |
569 | } |
570 | ||
e8a0464c DM |
571 | static void dev_deactivate_queue(struct net_device *dev, |
572 | struct netdev_queue *dev_queue, | |
573 | void *_qdisc_default) | |
b0e1e646 | 574 | { |
e8a0464c | 575 | struct Qdisc *qdisc_default = _qdisc_default; |
d3b753db | 576 | struct sk_buff *skb = NULL; |
970565bb | 577 | struct Qdisc *qdisc; |
970565bb | 578 | |
970565bb | 579 | qdisc = dev_queue->qdisc; |
b0e1e646 | 580 | if (qdisc) { |
83874000 DM |
581 | spin_lock_bh(qdisc_lock(qdisc)); |
582 | ||
b0e1e646 DM |
583 | dev_queue->qdisc = qdisc_default; |
584 | qdisc_reset(qdisc); | |
d3b753db | 585 | |
83874000 | 586 | spin_unlock_bh(qdisc_lock(qdisc)); |
b0e1e646 | 587 | } |
970565bb | 588 | |
970565bb | 589 | kfree_skb(skb); |
1da177e4 LT |
590 | } |
591 | ||
e8a0464c DM |
592 | static bool some_qdisc_is_running(struct net_device *dev, int lock) |
593 | { | |
594 | unsigned int i; | |
595 | ||
596 | for (i = 0; i < dev->num_tx_queues; i++) { | |
597 | struct netdev_queue *dev_queue; | |
7698b4fc | 598 | spinlock_t *root_lock; |
e2627c8c | 599 | struct Qdisc *q; |
e8a0464c DM |
600 | int val; |
601 | ||
602 | dev_queue = netdev_get_tx_queue(dev, i); | |
e2627c8c | 603 | q = dev_queue->qdisc; |
7698b4fc | 604 | root_lock = qdisc_root_lock(q); |
e8a0464c DM |
605 | |
606 | if (lock) | |
7698b4fc | 607 | spin_lock_bh(root_lock); |
e8a0464c | 608 | |
e2627c8c | 609 | val = test_bit(__QDISC_STATE_RUNNING, &q->state); |
e8a0464c DM |
610 | |
611 | if (lock) | |
7698b4fc | 612 | spin_unlock_bh(root_lock); |
e8a0464c DM |
613 | |
614 | if (val) | |
615 | return true; | |
616 | } | |
617 | return false; | |
618 | } | |
619 | ||
1da177e4 LT |
620 | void dev_deactivate(struct net_device *dev) |
621 | { | |
e8a0464c | 622 | bool running; |
1da177e4 | 623 | |
e8a0464c | 624 | netdev_for_each_tx_queue(dev, dev_deactivate_queue, &noop_qdisc); |
41a23b07 | 625 | |
1da177e4 LT |
626 | dev_watchdog_down(dev); |
627 | ||
ce0e32e6 | 628 | /* Wait for outstanding qdisc-less dev_queue_xmit calls. */ |
d4828d85 | 629 | synchronize_rcu(); |
1da177e4 | 630 | |
d4828d85 | 631 | /* Wait for outstanding qdisc_run calls. */ |
ce0e32e6 | 632 | do { |
e8a0464c | 633 | while (some_qdisc_is_running(dev, 0)) |
ce0e32e6 HX |
634 | yield(); |
635 | ||
636 | /* | |
637 | * Double-check inside queue lock to ensure that all effects | |
638 | * of the queue run are visible when we return. | |
639 | */ | |
e8a0464c | 640 | running = some_qdisc_is_running(dev, 1); |
ce0e32e6 HX |
641 | |
642 | /* | |
643 | * The running flag should never be set at this point because | |
644 | * we've already set dev->qdisc to noop_qdisc *inside* the same | |
645 | * pair of spin locks. That is, if any qdisc_run starts after | |
646 | * our initial test it should see the noop_qdisc and then | |
647 | * clear the RUNNING bit before dropping the queue lock. So | |
648 | * if it is set here then we've found a bug. | |
649 | */ | |
650 | } while (WARN_ON_ONCE(running)); | |
1da177e4 LT |
651 | } |
652 | ||
b0e1e646 DM |
653 | static void dev_init_scheduler_queue(struct net_device *dev, |
654 | struct netdev_queue *dev_queue, | |
e8a0464c | 655 | void *_qdisc) |
b0e1e646 | 656 | { |
e8a0464c DM |
657 | struct Qdisc *qdisc = _qdisc; |
658 | ||
b0e1e646 DM |
659 | dev_queue->qdisc = qdisc; |
660 | dev_queue->qdisc_sleeping = qdisc; | |
b0e1e646 DM |
661 | } |
662 | ||
1da177e4 LT |
663 | void dev_init_scheduler(struct net_device *dev) |
664 | { | |
e8a0464c | 665 | netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc); |
b0e1e646 | 666 | dev_init_scheduler_queue(dev, &dev->rx_queue, NULL); |
1da177e4 | 667 | |
b24b8a24 | 668 | setup_timer(&dev->watchdog_timer, dev_watchdog, (unsigned long)dev); |
1da177e4 LT |
669 | } |
670 | ||
e8a0464c DM |
671 | static void shutdown_scheduler_queue(struct net_device *dev, |
672 | struct netdev_queue *dev_queue, | |
673 | void *_qdisc_default) | |
1da177e4 | 674 | { |
b0e1e646 | 675 | struct Qdisc *qdisc = dev_queue->qdisc_sleeping; |
e8a0464c | 676 | struct Qdisc *qdisc_default = _qdisc_default; |
b0e1e646 DM |
677 | |
678 | if (qdisc) { | |
17715e62 DM |
679 | spinlock_t *root_lock = qdisc_root_lock(qdisc); |
680 | ||
b0e1e646 DM |
681 | dev_queue->qdisc = qdisc_default; |
682 | dev_queue->qdisc_sleeping = qdisc_default; | |
1da177e4 | 683 | |
17715e62 | 684 | spin_lock(root_lock); |
1da177e4 | 685 | qdisc_destroy(qdisc); |
17715e62 | 686 | spin_unlock(root_lock); |
10297b99 | 687 | } |
b0e1e646 DM |
688 | } |
689 | ||
690 | void dev_shutdown(struct net_device *dev) | |
691 | { | |
e8a0464c DM |
692 | netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc); |
693 | shutdown_scheduler_queue(dev, &dev->rx_queue, NULL); | |
1da177e4 | 694 | BUG_TRAP(!timer_pending(&dev->watchdog_timer)); |
1da177e4 | 695 | } |