4 * Linux wait queue related types and methods
6 #include <linux/list.h>
7 #include <linux/stddef.h>
8 #include <linux/spinlock.h>
9 #include <asm/current.h>
10 #include <uapi/linux/wait.h>
12 typedef struct __wait_queue wait_queue_t;
13 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key);
14 int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, void *key);
18 #define WQ_FLAG_EXCLUSIVE 0x01
20 wait_queue_func_t func;
21 struct list_head task_list;
27 #define WAIT_ATOMIC_T_BIT_NR -1
30 struct wait_bit_queue {
31 struct wait_bit_key key;
35 struct __wait_queue_head {
37 struct list_head task_list;
39 typedef struct __wait_queue_head wait_queue_head_t;
44 * Macros for declaration and initialisaton of the datatypes
47 #define __WAITQUEUE_INITIALIZER(name, tsk) { \
49 .func = default_wake_function, \
50 .task_list = { NULL, NULL } }
52 #define DECLARE_WAITQUEUE(name, tsk) \
53 wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
55 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \
56 .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
57 .task_list = { &(name).task_list, &(name).task_list } }
59 #define DECLARE_WAIT_QUEUE_HEAD(name) \
60 wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
62 #define __WAIT_BIT_KEY_INITIALIZER(word, bit) \
63 { .flags = word, .bit_nr = bit, }
65 #define __WAIT_ATOMIC_T_KEY_INITIALIZER(p) \
66 { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }
68 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
70 #define init_waitqueue_head(q) \
72 static struct lock_class_key __key; \
74 __init_waitqueue_head((q), #q, &__key); \
78 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
79 ({ init_waitqueue_head(&name); name; })
80 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
81 wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
83 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
86 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
90 q->func = default_wake_function;
94 init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func)
101 static inline int waitqueue_active(wait_queue_head_t *q)
103 return !list_empty(&q->task_list);
106 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
107 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
108 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
110 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
112 list_add(&new->task_list, &head->task_list);
116 * Used for wake-one threads:
119 __add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
121 wait->flags |= WQ_FLAG_EXCLUSIVE;
122 __add_wait_queue(q, wait);
125 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
128 list_add_tail(&new->task_list, &head->task_list);
132 __add_wait_queue_tail_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
134 wait->flags |= WQ_FLAG_EXCLUSIVE;
135 __add_wait_queue_tail(q, wait);
139 __remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old)
141 list_del(&old->task_list);
144 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
145 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
146 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
147 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
148 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
149 void __wake_up_bit(wait_queue_head_t *, void *, int);
150 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
151 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
152 void wake_up_bit(void *, int);
153 void wake_up_atomic_t(atomic_t *);
154 int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned);
155 int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned);
156 int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned);
157 wait_queue_head_t *bit_waitqueue(void *, int);
159 #define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL)
160 #define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL)
161 #define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL)
162 #define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL, 1)
163 #define wake_up_all_locked(x) __wake_up_locked((x), TASK_NORMAL, 0)
165 #define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
166 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
167 #define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
168 #define wake_up_interruptible_sync(x) __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
171 * Wakeup macros to be used to report events to the targets.
173 #define wake_up_poll(x, m) \
174 __wake_up(x, TASK_NORMAL, 1, (void *) (m))
175 #define wake_up_locked_poll(x, m) \
176 __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
177 #define wake_up_interruptible_poll(x, m) \
178 __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
179 #define wake_up_interruptible_sync_poll(x, m) \
180 __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
182 #define ___wait_cond_timeout(condition) \
184 bool __cond = (condition); \
185 if (__cond && !__ret) \
190 #define ___wait_is_interruptible(state) \
191 (!__builtin_constant_p(state) || \
192 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE) \
194 #define ___wait_event(wq, condition, state, exclusive, ret, cmd) \
197 wait_queue_t __wait; \
200 INIT_LIST_HEAD(&__wait.task_list); \
202 __wait.flags = WQ_FLAG_EXCLUSIVE; \
207 long __int = prepare_to_wait_event(&wq, &__wait, state);\
212 if (___wait_is_interruptible(state) && __int) { \
215 abort_exclusive_wait(&wq, &__wait, \
224 finish_wait(&wq, &__wait); \
228 #define __wait_event(wq, condition) \
229 (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
233 * wait_event - sleep until a condition gets true
234 * @wq: the waitqueue to wait on
235 * @condition: a C expression for the event to wait for
237 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
238 * @condition evaluates to true. The @condition is checked each time
239 * the waitqueue @wq is woken up.
241 * wake_up() has to be called after changing any variable that could
242 * change the result of the wait condition.
244 #define wait_event(wq, condition) \
248 __wait_event(wq, condition); \
251 #define __wait_event_timeout(wq, condition, timeout) \
252 ___wait_event(wq, ___wait_cond_timeout(condition), \
253 TASK_UNINTERRUPTIBLE, 0, timeout, \
254 __ret = schedule_timeout(__ret))
257 * wait_event_timeout - sleep until a condition gets true or a timeout elapses
258 * @wq: the waitqueue to wait on
259 * @condition: a C expression for the event to wait for
260 * @timeout: timeout, in jiffies
262 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
263 * @condition evaluates to true. The @condition is checked each time
264 * the waitqueue @wq is woken up.
266 * wake_up() has to be called after changing any variable that could
267 * change the result of the wait condition.
269 * The function returns 0 if the @timeout elapsed, or the remaining
270 * jiffies (at least 1) if the @condition evaluated to %true before
271 * the @timeout elapsed.
273 #define wait_event_timeout(wq, condition, timeout) \
275 long __ret = timeout; \
276 if (!___wait_cond_timeout(condition)) \
277 __ret = __wait_event_timeout(wq, condition, timeout); \
281 #define __wait_event_cmd(wq, condition, cmd1, cmd2) \
283 DEFINE_WAIT(__wait); \
286 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
293 finish_wait(&wq, &__wait); \
297 * wait_event_cmd - sleep until a condition gets true
298 * @wq: the waitqueue to wait on
299 * @condition: a C expression for the event to wait for
300 * cmd1: the command will be executed before sleep
301 * cmd2: the command will be executed after sleep
303 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
304 * @condition evaluates to true. The @condition is checked each time
305 * the waitqueue @wq is woken up.
307 * wake_up() has to be called after changing any variable that could
308 * change the result of the wait condition.
310 #define wait_event_cmd(wq, condition, cmd1, cmd2) \
314 __wait_event_cmd(wq, condition, cmd1, cmd2); \
317 #define __wait_event_interruptible(wq, condition) \
318 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \
322 * wait_event_interruptible - sleep until a condition gets true
323 * @wq: the waitqueue to wait on
324 * @condition: a C expression for the event to wait for
326 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
327 * @condition evaluates to true or a signal is received.
328 * The @condition is checked each time the waitqueue @wq is woken up.
330 * wake_up() has to be called after changing any variable that could
331 * change the result of the wait condition.
333 * The function will return -ERESTARTSYS if it was interrupted by a
334 * signal and 0 if @condition evaluated to true.
336 #define wait_event_interruptible(wq, condition) \
340 __ret = __wait_event_interruptible(wq, condition); \
344 #define __wait_event_interruptible_timeout(wq, condition, timeout) \
345 ___wait_event(wq, ___wait_cond_timeout(condition), \
346 TASK_INTERRUPTIBLE, 0, timeout, \
347 __ret = schedule_timeout(__ret))
350 * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
351 * @wq: the waitqueue to wait on
352 * @condition: a C expression for the event to wait for
353 * @timeout: timeout, in jiffies
355 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
356 * @condition evaluates to true or a signal is received.
357 * The @condition is checked each time the waitqueue @wq is woken up.
359 * wake_up() has to be called after changing any variable that could
360 * change the result of the wait condition.
363 * 0 if the @timeout elapsed, -%ERESTARTSYS if it was interrupted by
364 * a signal, or the remaining jiffies (at least 1) if the @condition
365 * evaluated to %true before the @timeout elapsed.
367 #define wait_event_interruptible_timeout(wq, condition, timeout) \
369 long __ret = timeout; \
370 if (!___wait_cond_timeout(condition)) \
371 __ret = __wait_event_interruptible_timeout(wq, \
372 condition, timeout); \
376 #define __wait_event_hrtimeout(wq, condition, timeout, state) \
379 struct hrtimer_sleeper __t; \
381 hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC, \
383 hrtimer_init_sleeper(&__t, current); \
384 if ((timeout).tv64 != KTIME_MAX) \
385 hrtimer_start_range_ns(&__t.timer, timeout, \
386 current->timer_slack_ns, \
389 __ret = ___wait_event(wq, condition, state, 0, 0, \
396 hrtimer_cancel(&__t.timer); \
397 destroy_hrtimer_on_stack(&__t.timer); \
402 * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
403 * @wq: the waitqueue to wait on
404 * @condition: a C expression for the event to wait for
405 * @timeout: timeout, as a ktime_t
407 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
408 * @condition evaluates to true or a signal is received.
409 * The @condition is checked each time the waitqueue @wq is woken up.
411 * wake_up() has to be called after changing any variable that could
412 * change the result of the wait condition.
414 * The function returns 0 if @condition became true, or -ETIME if the timeout
417 #define wait_event_hrtimeout(wq, condition, timeout) \
421 __ret = __wait_event_hrtimeout(wq, condition, timeout, \
422 TASK_UNINTERRUPTIBLE); \
427 * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
428 * @wq: the waitqueue to wait on
429 * @condition: a C expression for the event to wait for
430 * @timeout: timeout, as a ktime_t
432 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
433 * @condition evaluates to true or a signal is received.
434 * The @condition is checked each time the waitqueue @wq is woken up.
436 * wake_up() has to be called after changing any variable that could
437 * change the result of the wait condition.
439 * The function returns 0 if @condition became true, -ERESTARTSYS if it was
440 * interrupted by a signal, or -ETIME if the timeout elapsed.
442 #define wait_event_interruptible_hrtimeout(wq, condition, timeout) \
446 __ret = __wait_event_hrtimeout(wq, condition, timeout, \
447 TASK_INTERRUPTIBLE); \
451 #define __wait_event_interruptible_exclusive(wq, condition) \
452 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \
455 #define wait_event_interruptible_exclusive(wq, condition) \
459 __ret = __wait_event_interruptible_exclusive(wq, condition);\
464 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
467 DEFINE_WAIT(__wait); \
469 __wait.flags |= WQ_FLAG_EXCLUSIVE; \
471 if (likely(list_empty(&__wait.task_list))) \
472 __add_wait_queue_tail(&(wq), &__wait); \
473 set_current_state(TASK_INTERRUPTIBLE); \
474 if (signal_pending(current)) { \
475 __ret = -ERESTARTSYS; \
479 spin_unlock_irq(&(wq).lock); \
481 spin_unlock(&(wq).lock); \
484 spin_lock_irq(&(wq).lock); \
486 spin_lock(&(wq).lock); \
487 } while (!(condition)); \
488 __remove_wait_queue(&(wq), &__wait); \
489 __set_current_state(TASK_RUNNING); \
495 * wait_event_interruptible_locked - sleep until a condition gets true
496 * @wq: the waitqueue to wait on
497 * @condition: a C expression for the event to wait for
499 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
500 * @condition evaluates to true or a signal is received.
501 * The @condition is checked each time the waitqueue @wq is woken up.
503 * It must be called with wq.lock being held. This spinlock is
504 * unlocked while sleeping but @condition testing is done while lock
505 * is held and when this macro exits the lock is held.
507 * The lock is locked/unlocked using spin_lock()/spin_unlock()
508 * functions which must match the way they are locked/unlocked outside
511 * wake_up_locked() has to be called after changing any variable that could
512 * change the result of the wait condition.
514 * The function will return -ERESTARTSYS if it was interrupted by a
515 * signal and 0 if @condition evaluated to true.
517 #define wait_event_interruptible_locked(wq, condition) \
519 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
522 * wait_event_interruptible_locked_irq - sleep until a condition gets true
523 * @wq: the waitqueue to wait on
524 * @condition: a C expression for the event to wait for
526 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
527 * @condition evaluates to true or a signal is received.
528 * The @condition is checked each time the waitqueue @wq is woken up.
530 * It must be called with wq.lock being held. This spinlock is
531 * unlocked while sleeping but @condition testing is done while lock
532 * is held and when this macro exits the lock is held.
534 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
535 * functions which must match the way they are locked/unlocked outside
538 * wake_up_locked() has to be called after changing any variable that could
539 * change the result of the wait condition.
541 * The function will return -ERESTARTSYS if it was interrupted by a
542 * signal and 0 if @condition evaluated to true.
544 #define wait_event_interruptible_locked_irq(wq, condition) \
546 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
549 * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
550 * @wq: the waitqueue to wait on
551 * @condition: a C expression for the event to wait for
553 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
554 * @condition evaluates to true or a signal is received.
555 * The @condition is checked each time the waitqueue @wq is woken up.
557 * It must be called with wq.lock being held. This spinlock is
558 * unlocked while sleeping but @condition testing is done while lock
559 * is held and when this macro exits the lock is held.
561 * The lock is locked/unlocked using spin_lock()/spin_unlock()
562 * functions which must match the way they are locked/unlocked outside
565 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
566 * set thus when other process waits process on the list if this
567 * process is awaken further processes are not considered.
569 * wake_up_locked() has to be called after changing any variable that could
570 * change the result of the wait condition.
572 * The function will return -ERESTARTSYS if it was interrupted by a
573 * signal and 0 if @condition evaluated to true.
575 #define wait_event_interruptible_exclusive_locked(wq, condition) \
577 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
580 * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
581 * @wq: the waitqueue to wait on
582 * @condition: a C expression for the event to wait for
584 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
585 * @condition evaluates to true or a signal is received.
586 * The @condition is checked each time the waitqueue @wq is woken up.
588 * It must be called with wq.lock being held. This spinlock is
589 * unlocked while sleeping but @condition testing is done while lock
590 * is held and when this macro exits the lock is held.
592 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
593 * functions which must match the way they are locked/unlocked outside
596 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
597 * set thus when other process waits process on the list if this
598 * process is awaken further processes are not considered.
600 * wake_up_locked() has to be called after changing any variable that could
601 * change the result of the wait condition.
603 * The function will return -ERESTARTSYS if it was interrupted by a
604 * signal and 0 if @condition evaluated to true.
606 #define wait_event_interruptible_exclusive_locked_irq(wq, condition) \
608 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
611 #define __wait_event_killable(wq, condition) \
612 ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
615 * wait_event_killable - sleep until a condition gets true
616 * @wq: the waitqueue to wait on
617 * @condition: a C expression for the event to wait for
619 * The process is put to sleep (TASK_KILLABLE) until the
620 * @condition evaluates to true or a signal is received.
621 * The @condition is checked each time the waitqueue @wq is woken up.
623 * wake_up() has to be called after changing any variable that could
624 * change the result of the wait condition.
626 * The function will return -ERESTARTSYS if it was interrupted by a
627 * signal and 0 if @condition evaluated to true.
629 #define wait_event_killable(wq, condition) \
633 __ret = __wait_event_killable(wq, condition); \
638 #define __wait_event_lock_irq(wq, condition, lock, cmd) \
639 (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
640 spin_unlock_irq(&lock); \
643 spin_lock_irq(&lock))
646 * wait_event_lock_irq_cmd - sleep until a condition gets true. The
647 * condition is checked under the lock. This
648 * is expected to be called with the lock
650 * @wq: the waitqueue to wait on
651 * @condition: a C expression for the event to wait for
652 * @lock: a locked spinlock_t, which will be released before cmd
653 * and schedule() and reacquired afterwards.
654 * @cmd: a command which is invoked outside the critical section before
657 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
658 * @condition evaluates to true. The @condition is checked each time
659 * the waitqueue @wq is woken up.
661 * wake_up() has to be called after changing any variable that could
662 * change the result of the wait condition.
664 * This is supposed to be called while holding the lock. The lock is
665 * dropped before invoking the cmd and going to sleep and is reacquired
668 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd) \
672 __wait_event_lock_irq(wq, condition, lock, cmd); \
676 * wait_event_lock_irq - sleep until a condition gets true. The
677 * condition is checked under the lock. This
678 * is expected to be called with the lock
680 * @wq: the waitqueue to wait on
681 * @condition: a C expression for the event to wait for
682 * @lock: a locked spinlock_t, which will be released before schedule()
683 * and reacquired afterwards.
685 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
686 * @condition evaluates to true. The @condition is checked each time
687 * the waitqueue @wq is woken up.
689 * wake_up() has to be called after changing any variable that could
690 * change the result of the wait condition.
692 * This is supposed to be called while holding the lock. The lock is
693 * dropped before going to sleep and is reacquired afterwards.
695 #define wait_event_lock_irq(wq, condition, lock) \
699 __wait_event_lock_irq(wq, condition, lock, ); \
703 #define __wait_event_interruptible_lock_irq(wq, condition, lock, cmd) \
704 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \
705 spin_unlock_irq(&lock); \
708 spin_lock_irq(&lock))
711 * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
712 * The condition is checked under the lock. This is expected to
713 * be called with the lock taken.
714 * @wq: the waitqueue to wait on
715 * @condition: a C expression for the event to wait for
716 * @lock: a locked spinlock_t, which will be released before cmd and
717 * schedule() and reacquired afterwards.
718 * @cmd: a command which is invoked outside the critical section before
721 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
722 * @condition evaluates to true or a signal is received. The @condition is
723 * checked each time the waitqueue @wq is woken up.
725 * wake_up() has to be called after changing any variable that could
726 * change the result of the wait condition.
728 * This is supposed to be called while holding the lock. The lock is
729 * dropped before invoking the cmd and going to sleep and is reacquired
732 * The macro will return -ERESTARTSYS if it was interrupted by a signal
733 * and 0 if @condition evaluated to true.
735 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
739 __ret = __wait_event_interruptible_lock_irq(wq, \
740 condition, lock, cmd); \
745 * wait_event_interruptible_lock_irq - sleep until a condition gets true.
746 * The condition is checked under the lock. This is expected
747 * to be called with the lock taken.
748 * @wq: the waitqueue to wait on
749 * @condition: a C expression for the event to wait for
750 * @lock: a locked spinlock_t, which will be released before schedule()
751 * and reacquired afterwards.
753 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
754 * @condition evaluates to true or signal is received. The @condition is
755 * checked each time the waitqueue @wq is woken up.
757 * wake_up() has to be called after changing any variable that could
758 * change the result of the wait condition.
760 * This is supposed to be called while holding the lock. The lock is
761 * dropped before going to sleep and is reacquired afterwards.
763 * The macro will return -ERESTARTSYS if it was interrupted by a signal
764 * and 0 if @condition evaluated to true.
766 #define wait_event_interruptible_lock_irq(wq, condition, lock) \
770 __ret = __wait_event_interruptible_lock_irq(wq, \
775 #define __wait_event_interruptible_lock_irq_timeout(wq, condition, \
777 ___wait_event(wq, ___wait_cond_timeout(condition), \
778 TASK_INTERRUPTIBLE, 0, ret, \
779 spin_unlock_irq(&lock); \
780 __ret = schedule_timeout(__ret); \
781 spin_lock_irq(&lock));
784 * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
785 * true or a timeout elapses. The condition is checked under
786 * the lock. This is expected to be called with the lock taken.
787 * @wq: the waitqueue to wait on
788 * @condition: a C expression for the event to wait for
789 * @lock: a locked spinlock_t, which will be released before schedule()
790 * and reacquired afterwards.
791 * @timeout: timeout, in jiffies
793 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
794 * @condition evaluates to true or signal is received. The @condition is
795 * checked each time the waitqueue @wq is woken up.
797 * wake_up() has to be called after changing any variable that could
798 * change the result of the wait condition.
800 * This is supposed to be called while holding the lock. The lock is
801 * dropped before going to sleep and is reacquired afterwards.
803 * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
804 * was interrupted by a signal, and the remaining jiffies otherwise
805 * if the condition evaluated to true before the timeout elapsed.
807 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock, \
810 long __ret = timeout; \
811 if (!___wait_cond_timeout(condition)) \
812 __ret = __wait_event_interruptible_lock_irq_timeout( \
813 wq, condition, lock, timeout); \
819 * These are the old interfaces to sleep waiting for an event.
820 * They are racy. DO NOT use them, use the wait_event* interfaces above.
821 * We plan to remove these interfaces.
823 extern void sleep_on(wait_queue_head_t *q);
824 extern long sleep_on_timeout(wait_queue_head_t *q, signed long timeout);
825 extern void interruptible_sleep_on(wait_queue_head_t *q);
826 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q, signed long timeout);
829 * Waitqueues which are removed from the waitqueue_head at wakeup time
831 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
832 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
833 long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state);
834 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
835 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key);
836 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
837 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
839 #define DEFINE_WAIT_FUNC(name, function) \
840 wait_queue_t name = { \
841 .private = current, \
843 .task_list = LIST_HEAD_INIT((name).task_list), \
846 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
848 #define DEFINE_WAIT_BIT(name, word, bit) \
849 struct wait_bit_queue name = { \
850 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \
852 .private = current, \
853 .func = wake_bit_function, \
855 LIST_HEAD_INIT((name).wait.task_list), \
859 #define init_wait(wait) \
861 (wait)->private = current; \
862 (wait)->func = autoremove_wake_function; \
863 INIT_LIST_HEAD(&(wait)->task_list); \
868 * wait_on_bit - wait for a bit to be cleared
869 * @word: the word being waited on, a kernel virtual address
870 * @bit: the bit of the word being waited on
871 * @action: the function used to sleep, which may take special actions
872 * @mode: the task state to sleep in
874 * There is a standard hashed waitqueue table for generic use. This
875 * is the part of the hashtable's accessor API that waits on a bit.
876 * For instance, if one were to have waiters on a bitflag, one would
877 * call wait_on_bit() in threads waiting for the bit to clear.
878 * One uses wait_on_bit() where one is waiting for the bit to clear,
879 * but has no intention of setting it.
882 wait_on_bit(void *word, int bit, int (*action)(void *), unsigned mode)
884 if (!test_bit(bit, word))
886 return out_of_line_wait_on_bit(word, bit, action, mode);
890 * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
891 * @word: the word being waited on, a kernel virtual address
892 * @bit: the bit of the word being waited on
893 * @action: the function used to sleep, which may take special actions
894 * @mode: the task state to sleep in
896 * There is a standard hashed waitqueue table for generic use. This
897 * is the part of the hashtable's accessor API that waits on a bit
898 * when one intends to set it, for instance, trying to lock bitflags.
899 * For instance, if one were to have waiters trying to set bitflag
900 * and waiting for it to clear before setting it, one would call
901 * wait_on_bit() in threads waiting to be able to set the bit.
902 * One uses wait_on_bit_lock() where one is waiting for the bit to
903 * clear with the intention of setting it, and when done, clearing it.
906 wait_on_bit_lock(void *word, int bit, int (*action)(void *), unsigned mode)
908 if (!test_and_set_bit(bit, word))
910 return out_of_line_wait_on_bit_lock(word, bit, action, mode);
914 * wait_on_atomic_t - Wait for an atomic_t to become 0
915 * @val: The atomic value being waited on, a kernel virtual address
916 * @action: the function used to sleep, which may take special actions
917 * @mode: the task state to sleep in
919 * Wait for an atomic_t to become 0. We abuse the bit-wait waitqueue table for
920 * the purpose of getting a waitqueue, but we set the key to a bit number
921 * outside of the target 'word'.
924 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
926 if (atomic_read(val) == 0)
928 return out_of_line_wait_on_atomic_t(val, action, mode);
931 #endif /* _LINUX_WAIT_H */