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7#include "sched.h"
8
9void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *key)
10{
11 spin_lock_init(&wq_head->lock);
12 lockdep_set_class_and_name(&wq_head->lock, key, name);
13 INIT_LIST_HEAD(&wq_head->head);
14}
15
16EXPORT_SYMBOL(__init_waitqueue_head);
17
18void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
19{
20 unsigned long flags;
21
22 wq_entry->flags &= ~WQ_FLAG_EXCLUSIVE;
23 spin_lock_irqsave(&wq_head->lock, flags);
24 __add_wait_queue(wq_head, wq_entry);
25 spin_unlock_irqrestore(&wq_head->lock, flags);
26}
27EXPORT_SYMBOL(add_wait_queue);
28
29void add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
30{
31 unsigned long flags;
32
33 wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
34 spin_lock_irqsave(&wq_head->lock, flags);
35 __add_wait_queue_entry_tail(wq_head, wq_entry);
36 spin_unlock_irqrestore(&wq_head->lock, flags);
37}
38EXPORT_SYMBOL(add_wait_queue_exclusive);
39
40void add_wait_queue_priority(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
41{
42 unsigned long flags;
43
44 wq_entry->flags |= WQ_FLAG_EXCLUSIVE | WQ_FLAG_PRIORITY;
45 spin_lock_irqsave(&wq_head->lock, flags);
46 __add_wait_queue(wq_head, wq_entry);
47 spin_unlock_irqrestore(&wq_head->lock, flags);
48}
49EXPORT_SYMBOL_GPL(add_wait_queue_priority);
50
51void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
52{
53 unsigned long flags;
54
55 spin_lock_irqsave(&wq_head->lock, flags);
56 __remove_wait_queue(wq_head, wq_entry);
57 spin_unlock_irqrestore(&wq_head->lock, flags);
58}
59EXPORT_SYMBOL(remove_wait_queue);
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65
66#define WAITQUEUE_WALK_BREAK_CNT 64
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81static int __wake_up_common(struct wait_queue_head *wq_head, unsigned int mode,
82 int nr_exclusive, int wake_flags, void *key,
83 wait_queue_entry_t *bookmark)
84{
85 wait_queue_entry_t *curr, *next;
86 int cnt = 0;
87
88 lockdep_assert_held(&wq_head->lock);
89
90 if (bookmark && (bookmark->flags & WQ_FLAG_BOOKMARK)) {
91 curr = list_next_entry(bookmark, entry);
92
93 list_del(&bookmark->entry);
94 bookmark->flags = 0;
95 } else
96 curr = list_first_entry(&wq_head->head, wait_queue_entry_t, entry);
97
98 if (&curr->entry == &wq_head->head)
99 return nr_exclusive;
100
101 list_for_each_entry_safe_from(curr, next, &wq_head->head, entry) {
102 unsigned flags = curr->flags;
103 int ret;
104
105 if (flags & WQ_FLAG_BOOKMARK)
106 continue;
107
108 ret = curr->func(curr, mode, wake_flags, key);
109 if (ret < 0)
110 break;
111 if (ret && (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
112 break;
113
114 if (bookmark && (++cnt > WAITQUEUE_WALK_BREAK_CNT) &&
115 (&next->entry != &wq_head->head)) {
116 bookmark->flags = WQ_FLAG_BOOKMARK;
117 list_add_tail(&bookmark->entry, &next->entry);
118 break;
119 }
120 }
121
122 return nr_exclusive;
123}
124
125static void __wake_up_common_lock(struct wait_queue_head *wq_head, unsigned int mode,
126 int nr_exclusive, int wake_flags, void *key)
127{
128 unsigned long flags;
129 wait_queue_entry_t bookmark;
130
131 bookmark.flags = 0;
132 bookmark.private = NULL;
133 bookmark.func = NULL;
134 INIT_LIST_HEAD(&bookmark.entry);
135
136 do {
137 spin_lock_irqsave(&wq_head->lock, flags);
138 nr_exclusive = __wake_up_common(wq_head, mode, nr_exclusive,
139 wake_flags, key, &bookmark);
140 spin_unlock_irqrestore(&wq_head->lock, flags);
141 } while (bookmark.flags & WQ_FLAG_BOOKMARK);
142}
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154void __wake_up(struct wait_queue_head *wq_head, unsigned int mode,
155 int nr_exclusive, void *key)
156{
157 __wake_up_common_lock(wq_head, mode, nr_exclusive, 0, key);
158}
159EXPORT_SYMBOL(__wake_up);
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164void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr)
165{
166 __wake_up_common(wq_head, mode, nr, 0, NULL, NULL);
167}
168EXPORT_SYMBOL_GPL(__wake_up_locked);
169
170void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key)
171{
172 __wake_up_common(wq_head, mode, 1, 0, key, NULL);
173}
174EXPORT_SYMBOL_GPL(__wake_up_locked_key);
175
176void __wake_up_locked_key_bookmark(struct wait_queue_head *wq_head,
177 unsigned int mode, void *key, wait_queue_entry_t *bookmark)
178{
179 __wake_up_common(wq_head, mode, 1, 0, key, bookmark);
180}
181EXPORT_SYMBOL_GPL(__wake_up_locked_key_bookmark);
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199void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode,
200 void *key)
201{
202 if (unlikely(!wq_head))
203 return;
204
205 __wake_up_common_lock(wq_head, mode, 1, WF_SYNC, key);
206}
207EXPORT_SYMBOL_GPL(__wake_up_sync_key);
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225void __wake_up_locked_sync_key(struct wait_queue_head *wq_head,
226 unsigned int mode, void *key)
227{
228 __wake_up_common(wq_head, mode, 1, WF_SYNC, key, NULL);
229}
230EXPORT_SYMBOL_GPL(__wake_up_locked_sync_key);
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235void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode)
236{
237 __wake_up_sync_key(wq_head, mode, NULL);
238}
239EXPORT_SYMBOL_GPL(__wake_up_sync);
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253void
254prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state)
255{
256 unsigned long flags;
257
258 wq_entry->flags &= ~WQ_FLAG_EXCLUSIVE;
259 spin_lock_irqsave(&wq_head->lock, flags);
260 if (list_empty(&wq_entry->entry))
261 __add_wait_queue(wq_head, wq_entry);
262 set_current_state(state);
263 spin_unlock_irqrestore(&wq_head->lock, flags);
264}
265EXPORT_SYMBOL(prepare_to_wait);
266
267
268bool
269prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state)
270{
271 unsigned long flags;
272 bool was_empty = false;
273
274 wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
275 spin_lock_irqsave(&wq_head->lock, flags);
276 if (list_empty(&wq_entry->entry)) {
277 was_empty = list_empty(&wq_head->head);
278 __add_wait_queue_entry_tail(wq_head, wq_entry);
279 }
280 set_current_state(state);
281 spin_unlock_irqrestore(&wq_head->lock, flags);
282 return was_empty;
283}
284EXPORT_SYMBOL(prepare_to_wait_exclusive);
285
286void init_wait_entry(struct wait_queue_entry *wq_entry, int flags)
287{
288 wq_entry->flags = flags;
289 wq_entry->private = current;
290 wq_entry->func = autoremove_wake_function;
291 INIT_LIST_HEAD(&wq_entry->entry);
292}
293EXPORT_SYMBOL(init_wait_entry);
294
295long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state)
296{
297 unsigned long flags;
298 long ret = 0;
299
300 spin_lock_irqsave(&wq_head->lock, flags);
301 if (signal_pending_state(state, current)) {
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314 list_del_init(&wq_entry->entry);
315 ret = -ERESTARTSYS;
316 } else {
317 if (list_empty(&wq_entry->entry)) {
318 if (wq_entry->flags & WQ_FLAG_EXCLUSIVE)
319 __add_wait_queue_entry_tail(wq_head, wq_entry);
320 else
321 __add_wait_queue(wq_head, wq_entry);
322 }
323 set_current_state(state);
324 }
325 spin_unlock_irqrestore(&wq_head->lock, flags);
326
327 return ret;
328}
329EXPORT_SYMBOL(prepare_to_wait_event);
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338int do_wait_intr(wait_queue_head_t *wq, wait_queue_entry_t *wait)
339{
340 if (likely(list_empty(&wait->entry)))
341 __add_wait_queue_entry_tail(wq, wait);
342
343 set_current_state(TASK_INTERRUPTIBLE);
344 if (signal_pending(current))
345 return -ERESTARTSYS;
346
347 spin_unlock(&wq->lock);
348 schedule();
349 spin_lock(&wq->lock);
350
351 return 0;
352}
353EXPORT_SYMBOL(do_wait_intr);
354
355int do_wait_intr_irq(wait_queue_head_t *wq, wait_queue_entry_t *wait)
356{
357 if (likely(list_empty(&wait->entry)))
358 __add_wait_queue_entry_tail(wq, wait);
359
360 set_current_state(TASK_INTERRUPTIBLE);
361 if (signal_pending(current))
362 return -ERESTARTSYS;
363
364 spin_unlock_irq(&wq->lock);
365 schedule();
366 spin_lock_irq(&wq->lock);
367
368 return 0;
369}
370EXPORT_SYMBOL(do_wait_intr_irq);
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381void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
382{
383 unsigned long flags;
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385 __set_current_state(TASK_RUNNING);
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399 if (!list_empty_careful(&wq_entry->entry)) {
400 spin_lock_irqsave(&wq_head->lock, flags);
401 list_del_init(&wq_entry->entry);
402 spin_unlock_irqrestore(&wq_head->lock, flags);
403 }
404}
405EXPORT_SYMBOL(finish_wait);
406
407int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key)
408{
409 int ret = default_wake_function(wq_entry, mode, sync, key);
410
411 if (ret)
412 list_del_init_careful(&wq_entry->entry);
413
414 return ret;
415}
416EXPORT_SYMBOL(autoremove_wake_function);
417
418static inline bool is_kthread_should_stop(void)
419{
420 return (current->flags & PF_KTHREAD) && kthread_should_stop();
421}
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443long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout)
444{
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451 set_current_state(mode);
452 if (!(wq_entry->flags & WQ_FLAG_WOKEN) && !is_kthread_should_stop())
453 timeout = schedule_timeout(timeout);
454 __set_current_state(TASK_RUNNING);
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462 smp_store_mb(wq_entry->flags, wq_entry->flags & ~WQ_FLAG_WOKEN);
463
464 return timeout;
465}
466EXPORT_SYMBOL(wait_woken);
467
468int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key)
469{
470
471 smp_mb();
472 wq_entry->flags |= WQ_FLAG_WOKEN;
473
474 return default_wake_function(wq_entry, mode, sync, key);
475}
476EXPORT_SYMBOL(woken_wake_function);
477