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);
16 /* __wait_queue::flags */
17 #define WQ_FLAG_EXCLUSIVE 0x01
18 #define WQ_FLAG_WOKEN 0x02
23 wait_queue_func_t func;
24 struct list_head task_list;
30 #define WAIT_ATOMIC_T_BIT_NR -1
31 unsigned long timeout;
34 struct wait_bit_queue {
35 struct wait_bit_key key;
39 struct __wait_queue_head {
41 struct list_head task_list;
43 typedef struct __wait_queue_head wait_queue_head_t;
48 * Macros for declaration and initialisaton of the datatypes
51 #define __WAITQUEUE_INITIALIZER(name, tsk) { \
53 .func = default_wake_function, \
54 .task_list = { NULL, NULL } }
56 #define DECLARE_WAITQUEUE(name, tsk) \
57 wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
59 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \
60 .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
61 .task_list = { &(name).task_list, &(name).task_list } }
63 #define DECLARE_WAIT_QUEUE_HEAD(name) \
64 wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
66 #define __WAIT_BIT_KEY_INITIALIZER(word, bit) \
67 { .flags = word, .bit_nr = bit, }
69 #define __WAIT_ATOMIC_T_KEY_INITIALIZER(p) \
70 { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }
72 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
74 #define init_waitqueue_head(q) \
76 static struct lock_class_key __key; \
78 __init_waitqueue_head((q), #q, &__key); \
82 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
83 ({ init_waitqueue_head(&name); name; })
84 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
85 wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
87 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
90 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
94 q->func = default_wake_function;
98 init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func)
105 static inline int waitqueue_active(wait_queue_head_t *q)
107 return !list_empty(&q->task_list);
110 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
111 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
112 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
114 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
116 list_add(&new->task_list, &head->task_list);
120 * Used for wake-one threads:
123 __add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
125 wait->flags |= WQ_FLAG_EXCLUSIVE;
126 __add_wait_queue(q, wait);
129 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
132 list_add_tail(&new->task_list, &head->task_list);
136 __add_wait_queue_tail_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
138 wait->flags |= WQ_FLAG_EXCLUSIVE;
139 __add_wait_queue_tail(q, wait);
143 __remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old)
145 list_del(&old->task_list);
148 typedef int wait_bit_action_f(struct wait_bit_key *);
149 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
150 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
151 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
152 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
153 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
154 void __wake_up_bit(wait_queue_head_t *, void *, int);
155 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
156 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
157 void wake_up_bit(void *, int);
158 void wake_up_atomic_t(atomic_t *);
159 int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned);
160 int out_of_line_wait_on_bit_timeout(void *, int, wait_bit_action_f *, unsigned, unsigned long);
161 int out_of_line_wait_on_bit_lock(void *, int, wait_bit_action_f *, unsigned);
162 int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned);
163 wait_queue_head_t *bit_waitqueue(void *, int);
165 #define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL)
166 #define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL)
167 #define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL)
168 #define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL, 1)
169 #define wake_up_all_locked(x) __wake_up_locked((x), TASK_NORMAL, 0)
171 #define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
172 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
173 #define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
174 #define wake_up_interruptible_sync(x) __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
177 * Wakeup macros to be used to report events to the targets.
179 #define wake_up_poll(x, m) \
180 __wake_up(x, TASK_NORMAL, 1, (void *) (m))
181 #define wake_up_locked_poll(x, m) \
182 __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
183 #define wake_up_interruptible_poll(x, m) \
184 __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
185 #define wake_up_interruptible_sync_poll(x, m) \
186 __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
188 #define ___wait_cond_timeout(condition) \
190 bool __cond = (condition); \
191 if (__cond && !__ret) \
196 #define ___wait_is_interruptible(state) \
197 (!__builtin_constant_p(state) || \
198 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE) \
201 * The below macro ___wait_event() has an explicit shadow of the __ret
202 * variable when used from the wait_event_*() macros.
204 * This is so that both can use the ___wait_cond_timeout() construct
205 * to wrap the condition.
207 * The type inconsistency of the wait_event_*() __ret variable is also
208 * on purpose; we use long where we can return timeout values and int
212 #define ___wait_event(wq, condition, state, exclusive, ret, cmd) \
215 wait_queue_t __wait; \
216 long __ret = ret; /* explicit shadow */ \
218 INIT_LIST_HEAD(&__wait.task_list); \
220 __wait.flags = WQ_FLAG_EXCLUSIVE; \
225 long __int = prepare_to_wait_event(&wq, &__wait, state);\
230 if (___wait_is_interruptible(state) && __int) { \
233 abort_exclusive_wait(&wq, &__wait, \
242 finish_wait(&wq, &__wait); \
246 #define __wait_event(wq, condition) \
247 (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
251 * wait_event - sleep until a condition gets true
252 * @wq: the waitqueue to wait on
253 * @condition: a C expression for the event to wait for
255 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
256 * @condition evaluates to true. The @condition is checked each time
257 * the waitqueue @wq is woken up.
259 * wake_up() has to be called after changing any variable that could
260 * change the result of the wait condition.
262 #define wait_event(wq, condition) \
267 __wait_event(wq, condition); \
270 #define __wait_event_freezable(wq, condition) \
271 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \
272 schedule(); try_to_freeze())
275 * wait_event - sleep (or freeze) until a condition gets true
276 * @wq: the waitqueue to wait on
277 * @condition: a C expression for the event to wait for
279 * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
280 * to system load) until the @condition evaluates to true. The
281 * @condition is checked each time the waitqueue @wq is woken up.
283 * wake_up() has to be called after changing any variable that could
284 * change the result of the wait condition.
286 #define wait_event_freezable(wq, condition) \
291 __ret = __wait_event_freezable(wq, condition); \
295 #define __wait_event_timeout(wq, condition, timeout) \
296 ___wait_event(wq, ___wait_cond_timeout(condition), \
297 TASK_UNINTERRUPTIBLE, 0, timeout, \
298 __ret = schedule_timeout(__ret))
301 * wait_event_timeout - sleep until a condition gets true or a timeout elapses
302 * @wq: the waitqueue to wait on
303 * @condition: a C expression for the event to wait for
304 * @timeout: timeout, in jiffies
306 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
307 * @condition evaluates to true. The @condition is checked each time
308 * the waitqueue @wq is woken up.
310 * wake_up() has to be called after changing any variable that could
311 * change the result of the wait condition.
314 * 0 if the @condition evaluated to %false after the @timeout elapsed,
315 * 1 if the @condition evaluated to %true after the @timeout elapsed,
316 * or the remaining jiffies (at least 1) if the @condition evaluated
317 * to %true before the @timeout elapsed.
319 #define wait_event_timeout(wq, condition, timeout) \
321 long __ret = timeout; \
323 if (!___wait_cond_timeout(condition)) \
324 __ret = __wait_event_timeout(wq, condition, timeout); \
328 #define __wait_event_freezable_timeout(wq, condition, timeout) \
329 ___wait_event(wq, ___wait_cond_timeout(condition), \
330 TASK_INTERRUPTIBLE, 0, timeout, \
331 __ret = schedule_timeout(__ret); try_to_freeze())
334 * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
335 * increasing load and is freezable.
337 #define wait_event_freezable_timeout(wq, condition, timeout) \
339 long __ret = timeout; \
341 if (!___wait_cond_timeout(condition)) \
342 __ret = __wait_event_freezable_timeout(wq, condition, timeout); \
346 #define __wait_event_cmd(wq, condition, cmd1, cmd2) \
347 (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
348 cmd1; schedule(); cmd2)
351 * wait_event_cmd - sleep until a condition gets true
352 * @wq: the waitqueue to wait on
353 * @condition: a C expression for the event to wait for
354 * @cmd1: the command will be executed before sleep
355 * @cmd2: the command will be executed after sleep
357 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
358 * @condition evaluates to true. The @condition is checked each time
359 * the waitqueue @wq is woken up.
361 * wake_up() has to be called after changing any variable that could
362 * change the result of the wait condition.
364 #define wait_event_cmd(wq, condition, cmd1, cmd2) \
369 __wait_event_cmd(wq, condition, cmd1, cmd2); \
372 #define __wait_event_interruptible(wq, condition) \
373 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \
377 * wait_event_interruptible - sleep until a condition gets true
378 * @wq: the waitqueue to wait on
379 * @condition: a C expression for the event to wait for
381 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
382 * @condition evaluates to true or a signal is received.
383 * The @condition is checked each time the waitqueue @wq is woken up.
385 * wake_up() has to be called after changing any variable that could
386 * change the result of the wait condition.
388 * The function will return -ERESTARTSYS if it was interrupted by a
389 * signal and 0 if @condition evaluated to true.
391 #define wait_event_interruptible(wq, condition) \
396 __ret = __wait_event_interruptible(wq, condition); \
400 #define __wait_event_interruptible_timeout(wq, condition, timeout) \
401 ___wait_event(wq, ___wait_cond_timeout(condition), \
402 TASK_INTERRUPTIBLE, 0, timeout, \
403 __ret = schedule_timeout(__ret))
406 * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
407 * @wq: the waitqueue to wait on
408 * @condition: a C expression for the event to wait for
409 * @timeout: timeout, in jiffies
411 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
412 * @condition evaluates to true or a signal is received.
413 * The @condition is checked each time the waitqueue @wq is woken up.
415 * wake_up() has to be called after changing any variable that could
416 * change the result of the wait condition.
419 * 0 if the @condition evaluated to %false after the @timeout elapsed,
420 * 1 if the @condition evaluated to %true after the @timeout elapsed,
421 * the remaining jiffies (at least 1) if the @condition evaluated
422 * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
423 * interrupted by a signal.
425 #define wait_event_interruptible_timeout(wq, condition, timeout) \
427 long __ret = timeout; \
429 if (!___wait_cond_timeout(condition)) \
430 __ret = __wait_event_interruptible_timeout(wq, \
431 condition, timeout); \
435 #define __wait_event_hrtimeout(wq, condition, timeout, state) \
438 struct hrtimer_sleeper __t; \
440 hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC, \
442 hrtimer_init_sleeper(&__t, current); \
443 if ((timeout).tv64 != KTIME_MAX) \
444 hrtimer_start_range_ns(&__t.timer, timeout, \
445 current->timer_slack_ns, \
448 __ret = ___wait_event(wq, condition, state, 0, 0, \
455 hrtimer_cancel(&__t.timer); \
456 destroy_hrtimer_on_stack(&__t.timer); \
461 * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
462 * @wq: the waitqueue to wait on
463 * @condition: a C expression for the event to wait for
464 * @timeout: timeout, as a ktime_t
466 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
467 * @condition evaluates to true or a signal is received.
468 * The @condition is checked each time the waitqueue @wq is woken up.
470 * wake_up() has to be called after changing any variable that could
471 * change the result of the wait condition.
473 * The function returns 0 if @condition became true, or -ETIME if the timeout
476 #define wait_event_hrtimeout(wq, condition, timeout) \
481 __ret = __wait_event_hrtimeout(wq, condition, timeout, \
482 TASK_UNINTERRUPTIBLE); \
487 * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
488 * @wq: the waitqueue to wait on
489 * @condition: a C expression for the event to wait for
490 * @timeout: timeout, as a ktime_t
492 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
493 * @condition evaluates to true or a signal is received.
494 * The @condition is checked each time the waitqueue @wq is woken up.
496 * wake_up() has to be called after changing any variable that could
497 * change the result of the wait condition.
499 * The function returns 0 if @condition became true, -ERESTARTSYS if it was
500 * interrupted by a signal, or -ETIME if the timeout elapsed.
502 #define wait_event_interruptible_hrtimeout(wq, condition, timeout) \
507 __ret = __wait_event_hrtimeout(wq, condition, timeout, \
508 TASK_INTERRUPTIBLE); \
512 #define __wait_event_interruptible_exclusive(wq, condition) \
513 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \
516 #define wait_event_interruptible_exclusive(wq, condition) \
521 __ret = __wait_event_interruptible_exclusive(wq, condition);\
526 #define __wait_event_freezable_exclusive(wq, condition) \
527 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \
528 schedule(); try_to_freeze())
530 #define wait_event_freezable_exclusive(wq, condition) \
535 __ret = __wait_event_freezable_exclusive(wq, condition);\
540 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
543 DEFINE_WAIT(__wait); \
545 __wait.flags |= WQ_FLAG_EXCLUSIVE; \
547 if (likely(list_empty(&__wait.task_list))) \
548 __add_wait_queue_tail(&(wq), &__wait); \
549 set_current_state(TASK_INTERRUPTIBLE); \
550 if (signal_pending(current)) { \
551 __ret = -ERESTARTSYS; \
555 spin_unlock_irq(&(wq).lock); \
557 spin_unlock(&(wq).lock); \
560 spin_lock_irq(&(wq).lock); \
562 spin_lock(&(wq).lock); \
563 } while (!(condition)); \
564 __remove_wait_queue(&(wq), &__wait); \
565 __set_current_state(TASK_RUNNING); \
571 * wait_event_interruptible_locked - sleep until a condition gets true
572 * @wq: the waitqueue to wait on
573 * @condition: a C expression for the event to wait for
575 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
576 * @condition evaluates to true or a signal is received.
577 * The @condition is checked each time the waitqueue @wq is woken up.
579 * It must be called with wq.lock being held. This spinlock is
580 * unlocked while sleeping but @condition testing is done while lock
581 * is held and when this macro exits the lock is held.
583 * The lock is locked/unlocked using spin_lock()/spin_unlock()
584 * functions which must match the way they are locked/unlocked outside
587 * wake_up_locked() has to be called after changing any variable that could
588 * change the result of the wait condition.
590 * The function will return -ERESTARTSYS if it was interrupted by a
591 * signal and 0 if @condition evaluated to true.
593 #define wait_event_interruptible_locked(wq, condition) \
595 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
598 * wait_event_interruptible_locked_irq - sleep until a condition gets true
599 * @wq: the waitqueue to wait on
600 * @condition: a C expression for the event to wait for
602 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
603 * @condition evaluates to true or a signal is received.
604 * The @condition is checked each time the waitqueue @wq is woken up.
606 * It must be called with wq.lock being held. This spinlock is
607 * unlocked while sleeping but @condition testing is done while lock
608 * is held and when this macro exits the lock is held.
610 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
611 * functions which must match the way they are locked/unlocked outside
614 * wake_up_locked() has to be called after changing any variable that could
615 * change the result of the wait condition.
617 * The function will return -ERESTARTSYS if it was interrupted by a
618 * signal and 0 if @condition evaluated to true.
620 #define wait_event_interruptible_locked_irq(wq, condition) \
622 ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
625 * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
626 * @wq: the waitqueue to wait on
627 * @condition: a C expression for the event to wait for
629 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
630 * @condition evaluates to true or a signal is received.
631 * The @condition is checked each time the waitqueue @wq is woken up.
633 * It must be called with wq.lock being held. This spinlock is
634 * unlocked while sleeping but @condition testing is done while lock
635 * is held and when this macro exits the lock is held.
637 * The lock is locked/unlocked using spin_lock()/spin_unlock()
638 * functions which must match the way they are locked/unlocked outside
641 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
642 * set thus when other process waits process on the list if this
643 * process is awaken further processes are not considered.
645 * wake_up_locked() has to be called after changing any variable that could
646 * change the result of the wait condition.
648 * The function will return -ERESTARTSYS if it was interrupted by a
649 * signal and 0 if @condition evaluated to true.
651 #define wait_event_interruptible_exclusive_locked(wq, condition) \
653 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
656 * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
657 * @wq: the waitqueue to wait on
658 * @condition: a C expression for the event to wait for
660 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
661 * @condition evaluates to true or a signal is received.
662 * The @condition is checked each time the waitqueue @wq is woken up.
664 * It must be called with wq.lock being held. This spinlock is
665 * unlocked while sleeping but @condition testing is done while lock
666 * is held and when this macro exits the lock is held.
668 * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
669 * functions which must match the way they are locked/unlocked outside
672 * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
673 * set thus when other process waits process on the list if this
674 * process is awaken further processes are not considered.
676 * wake_up_locked() has to be called after changing any variable that could
677 * change the result of the wait condition.
679 * The function will return -ERESTARTSYS if it was interrupted by a
680 * signal and 0 if @condition evaluated to true.
682 #define wait_event_interruptible_exclusive_locked_irq(wq, condition) \
684 ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
687 #define __wait_event_killable(wq, condition) \
688 ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
691 * wait_event_killable - sleep until a condition gets true
692 * @wq: the waitqueue to wait on
693 * @condition: a C expression for the event to wait for
695 * The process is put to sleep (TASK_KILLABLE) until the
696 * @condition evaluates to true or a signal is received.
697 * The @condition is checked each time the waitqueue @wq is woken up.
699 * wake_up() has to be called after changing any variable that could
700 * change the result of the wait condition.
702 * The function will return -ERESTARTSYS if it was interrupted by a
703 * signal and 0 if @condition evaluated to true.
705 #define wait_event_killable(wq, condition) \
710 __ret = __wait_event_killable(wq, condition); \
715 #define __wait_event_lock_irq(wq, condition, lock, cmd) \
716 (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
717 spin_unlock_irq(&lock); \
720 spin_lock_irq(&lock))
723 * wait_event_lock_irq_cmd - sleep until a condition gets true. The
724 * condition is checked under the lock. This
725 * is expected to be called with the lock
727 * @wq: the waitqueue to wait on
728 * @condition: a C expression for the event to wait for
729 * @lock: a locked spinlock_t, which will be released before cmd
730 * and schedule() and reacquired afterwards.
731 * @cmd: a command which is invoked outside the critical section before
734 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
735 * @condition evaluates to true. The @condition is checked each time
736 * the waitqueue @wq is woken up.
738 * wake_up() has to be called after changing any variable that could
739 * change the result of the wait condition.
741 * This is supposed to be called while holding the lock. The lock is
742 * dropped before invoking the cmd and going to sleep and is reacquired
745 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd) \
749 __wait_event_lock_irq(wq, condition, lock, cmd); \
753 * wait_event_lock_irq - sleep until a condition gets true. The
754 * condition is checked under the lock. This
755 * is expected to be called with the lock
757 * @wq: the waitqueue to wait on
758 * @condition: a C expression for the event to wait for
759 * @lock: a locked spinlock_t, which will be released before schedule()
760 * and reacquired afterwards.
762 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
763 * @condition evaluates to true. The @condition is checked each time
764 * the waitqueue @wq is woken up.
766 * wake_up() has to be called after changing any variable that could
767 * change the result of the wait condition.
769 * This is supposed to be called while holding the lock. The lock is
770 * dropped before going to sleep and is reacquired afterwards.
772 #define wait_event_lock_irq(wq, condition, lock) \
776 __wait_event_lock_irq(wq, condition, lock, ); \
780 #define __wait_event_interruptible_lock_irq(wq, condition, lock, cmd) \
781 ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \
782 spin_unlock_irq(&lock); \
785 spin_lock_irq(&lock))
788 * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
789 * The condition is checked under the lock. This is expected to
790 * be called with the lock taken.
791 * @wq: the waitqueue to wait on
792 * @condition: a C expression for the event to wait for
793 * @lock: a locked spinlock_t, which will be released before cmd and
794 * schedule() and reacquired afterwards.
795 * @cmd: a command which is invoked outside the critical section before
798 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
799 * @condition evaluates to true or a signal is received. The @condition is
800 * checked each time the waitqueue @wq is woken up.
802 * wake_up() has to be called after changing any variable that could
803 * change the result of the wait condition.
805 * This is supposed to be called while holding the lock. The lock is
806 * dropped before invoking the cmd and going to sleep and is reacquired
809 * The macro will return -ERESTARTSYS if it was interrupted by a signal
810 * and 0 if @condition evaluated to true.
812 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
816 __ret = __wait_event_interruptible_lock_irq(wq, \
817 condition, lock, cmd); \
822 * wait_event_interruptible_lock_irq - sleep until a condition gets true.
823 * The condition is checked under the lock. This is expected
824 * to be called with the lock taken.
825 * @wq: the waitqueue to wait on
826 * @condition: a C expression for the event to wait for
827 * @lock: a locked spinlock_t, which will be released before schedule()
828 * and reacquired afterwards.
830 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
831 * @condition evaluates to true or signal is received. The @condition is
832 * checked each time the waitqueue @wq is woken up.
834 * wake_up() has to be called after changing any variable that could
835 * change the result of the wait condition.
837 * This is supposed to be called while holding the lock. The lock is
838 * dropped before going to sleep and is reacquired afterwards.
840 * The macro will return -ERESTARTSYS if it was interrupted by a signal
841 * and 0 if @condition evaluated to true.
843 #define wait_event_interruptible_lock_irq(wq, condition, lock) \
847 __ret = __wait_event_interruptible_lock_irq(wq, \
852 #define __wait_event_interruptible_lock_irq_timeout(wq, condition, \
854 ___wait_event(wq, ___wait_cond_timeout(condition), \
855 TASK_INTERRUPTIBLE, 0, timeout, \
856 spin_unlock_irq(&lock); \
857 __ret = schedule_timeout(__ret); \
858 spin_lock_irq(&lock));
861 * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
862 * true or a timeout elapses. The condition is checked under
863 * the lock. This is expected to be called with the lock taken.
864 * @wq: the waitqueue to wait on
865 * @condition: a C expression for the event to wait for
866 * @lock: a locked spinlock_t, which will be released before schedule()
867 * and reacquired afterwards.
868 * @timeout: timeout, in jiffies
870 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
871 * @condition evaluates to true or signal is received. The @condition is
872 * checked each time the waitqueue @wq is woken up.
874 * wake_up() has to be called after changing any variable that could
875 * change the result of the wait condition.
877 * This is supposed to be called while holding the lock. The lock is
878 * dropped before going to sleep and is reacquired afterwards.
880 * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
881 * was interrupted by a signal, and the remaining jiffies otherwise
882 * if the condition evaluated to true before the timeout elapsed.
884 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock, \
887 long __ret = timeout; \
888 if (!___wait_cond_timeout(condition)) \
889 __ret = __wait_event_interruptible_lock_irq_timeout( \
890 wq, condition, lock, timeout); \
895 * Waitqueues which are removed from the waitqueue_head at wakeup time
897 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
898 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
899 long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state);
900 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
901 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key);
902 long wait_woken(wait_queue_t *wait, unsigned mode, long timeout);
903 int woken_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
904 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
905 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
907 #define DEFINE_WAIT_FUNC(name, function) \
908 wait_queue_t name = { \
909 .private = current, \
911 .task_list = LIST_HEAD_INIT((name).task_list), \
914 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
916 #define DEFINE_WAIT_BIT(name, word, bit) \
917 struct wait_bit_queue name = { \
918 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \
920 .private = current, \
921 .func = wake_bit_function, \
923 LIST_HEAD_INIT((name).wait.task_list), \
927 #define init_wait(wait) \
929 (wait)->private = current; \
930 (wait)->func = autoremove_wake_function; \
931 INIT_LIST_HEAD(&(wait)->task_list); \
936 extern int bit_wait(struct wait_bit_key *);
937 extern int bit_wait_io(struct wait_bit_key *);
938 extern int bit_wait_timeout(struct wait_bit_key *);
939 extern int bit_wait_io_timeout(struct wait_bit_key *);
942 * wait_on_bit - wait for a bit to be cleared
943 * @word: the word being waited on, a kernel virtual address
944 * @bit: the bit of the word being waited on
945 * @mode: the task state to sleep in
947 * There is a standard hashed waitqueue table for generic use. This
948 * is the part of the hashtable's accessor API that waits on a bit.
949 * For instance, if one were to have waiters on a bitflag, one would
950 * call wait_on_bit() in threads waiting for the bit to clear.
951 * One uses wait_on_bit() where one is waiting for the bit to clear,
952 * but has no intention of setting it.
953 * Returned value will be zero if the bit was cleared, or non-zero
954 * if the process received a signal and the mode permitted wakeup
958 wait_on_bit(void *word, int bit, unsigned mode)
961 if (!test_bit(bit, word))
963 return out_of_line_wait_on_bit(word, bit,
969 * wait_on_bit_io - wait for a bit to be cleared
970 * @word: the word being waited on, a kernel virtual address
971 * @bit: the bit of the word being waited on
972 * @mode: the task state to sleep in
974 * Use the standard hashed waitqueue table to wait for a bit
975 * to be cleared. This is similar to wait_on_bit(), but calls
976 * io_schedule() instead of schedule() for the actual waiting.
978 * Returned value will be zero if the bit was cleared, or non-zero
979 * if the process received a signal and the mode permitted wakeup
983 wait_on_bit_io(void *word, int bit, unsigned mode)
986 if (!test_bit(bit, word))
988 return out_of_line_wait_on_bit(word, bit,
994 * wait_on_bit_action - wait for a bit to be cleared
995 * @word: the word being waited on, a kernel virtual address
996 * @bit: the bit of the word being waited on
997 * @action: the function used to sleep, which may take special actions
998 * @mode: the task state to sleep in
1000 * Use the standard hashed waitqueue table to wait for a bit
1001 * to be cleared, and allow the waiting action to be specified.
1002 * This is like wait_on_bit() but allows fine control of how the waiting
1005 * Returned value will be zero if the bit was cleared, or non-zero
1006 * if the process received a signal and the mode permitted wakeup
1010 wait_on_bit_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
1013 if (!test_bit(bit, word))
1015 return out_of_line_wait_on_bit(word, bit, action, mode);
1019 * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
1020 * @word: the word being waited on, a kernel virtual address
1021 * @bit: the bit of the word being waited on
1022 * @mode: the task state to sleep in
1024 * There is a standard hashed waitqueue table for generic use. This
1025 * is the part of the hashtable's accessor API that waits on a bit
1026 * when one intends to set it, for instance, trying to lock bitflags.
1027 * For instance, if one were to have waiters trying to set bitflag
1028 * and waiting for it to clear before setting it, one would call
1029 * wait_on_bit() in threads waiting to be able to set the bit.
1030 * One uses wait_on_bit_lock() where one is waiting for the bit to
1031 * clear with the intention of setting it, and when done, clearing it.
1033 * Returns zero if the bit was (eventually) found to be clear and was
1034 * set. Returns non-zero if a signal was delivered to the process and
1035 * the @mode allows that signal to wake the process.
1038 wait_on_bit_lock(void *word, int bit, unsigned mode)
1041 if (!test_and_set_bit(bit, word))
1043 return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode);
1047 * wait_on_bit_lock_io - wait for a bit to be cleared, when wanting to set it
1048 * @word: the word being waited on, a kernel virtual address
1049 * @bit: the bit of the word being waited on
1050 * @mode: the task state to sleep in
1052 * Use the standard hashed waitqueue table to wait for a bit
1053 * to be cleared and then to atomically set it. This is similar
1054 * to wait_on_bit(), but calls io_schedule() instead of schedule()
1055 * for the actual waiting.
1057 * Returns zero if the bit was (eventually) found to be clear and was
1058 * set. Returns non-zero if a signal was delivered to the process and
1059 * the @mode allows that signal to wake the process.
1062 wait_on_bit_lock_io(void *word, int bit, unsigned mode)
1065 if (!test_and_set_bit(bit, word))
1067 return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode);
1071 * wait_on_bit_lock_action - wait for a bit to be cleared, when wanting to set it
1072 * @word: the word being waited on, a kernel virtual address
1073 * @bit: the bit of the word being waited on
1074 * @action: the function used to sleep, which may take special actions
1075 * @mode: the task state to sleep in
1077 * Use the standard hashed waitqueue table to wait for a bit
1078 * to be cleared and then to set it, and allow the waiting action
1080 * This is like wait_on_bit() but allows fine control of how the waiting
1083 * Returns zero if the bit was (eventually) found to be clear and was
1084 * set. Returns non-zero if a signal was delivered to the process and
1085 * the @mode allows that signal to wake the process.
1088 wait_on_bit_lock_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
1091 if (!test_and_set_bit(bit, word))
1093 return out_of_line_wait_on_bit_lock(word, bit, action, mode);
1097 * wait_on_atomic_t - Wait for an atomic_t to become 0
1098 * @val: The atomic value being waited on, a kernel virtual address
1099 * @action: the function used to sleep, which may take special actions
1100 * @mode: the task state to sleep in
1102 * Wait for an atomic_t to become 0. We abuse the bit-wait waitqueue table for
1103 * the purpose of getting a waitqueue, but we set the key to a bit number
1104 * outside of the target 'word'.
1107 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
1110 if (atomic_read(val) == 0)
1112 return out_of_line_wait_on_atomic_t(val, action, mode);
1115 #endif /* _LINUX_WAIT_H */