Version:  2.0.40 2.2.26 2.4.37 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0

Linux/include/linux/wait.h

  1 #ifndef _LINUX_WAIT_H
  2 #define _LINUX_WAIT_H
  3 /*
  4  * Linux wait queue related types and methods
  5  */
  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>
 11 
 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);
 15 
 16 /* __wait_queue::flags */
 17 #define WQ_FLAG_EXCLUSIVE       0x01
 18 #define WQ_FLAG_WOKEN           0x02
 19 
 20 struct __wait_queue {
 21         unsigned int            flags;
 22         void                    *private;
 23         wait_queue_func_t       func;
 24         struct list_head        task_list;
 25 };
 26 
 27 struct wait_bit_key {
 28         void                    *flags;
 29         int                     bit_nr;
 30 #define WAIT_ATOMIC_T_BIT_NR    -1
 31         unsigned long           timeout;
 32 };
 33 
 34 struct wait_bit_queue {
 35         struct wait_bit_key     key;
 36         wait_queue_t            wait;
 37 };
 38 
 39 struct __wait_queue_head {
 40         spinlock_t              lock;
 41         struct list_head        task_list;
 42 };
 43 typedef struct __wait_queue_head wait_queue_head_t;
 44 
 45 struct task_struct;
 46 
 47 /*
 48  * Macros for declaration and initialisaton of the datatypes
 49  */
 50 
 51 #define __WAITQUEUE_INITIALIZER(name, tsk) {                            \
 52         .private        = tsk,                                          \
 53         .func           = default_wake_function,                        \
 54         .task_list      = { NULL, NULL } }
 55 
 56 #define DECLARE_WAITQUEUE(name, tsk)                                    \
 57         wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
 58 
 59 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                           \
 60         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),              \
 61         .task_list      = { &(name).task_list, &(name).task_list } }
 62 
 63 #define DECLARE_WAIT_QUEUE_HEAD(name) \
 64         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
 65 
 66 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)                           \
 67         { .flags = word, .bit_nr = bit, }
 68 
 69 #define __WAIT_ATOMIC_T_KEY_INITIALIZER(p)                              \
 70         { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }
 71 
 72 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
 73 
 74 #define init_waitqueue_head(q)                          \
 75         do {                                            \
 76                 static struct lock_class_key __key;     \
 77                                                         \
 78                 __init_waitqueue_head((q), #q, &__key); \
 79         } while (0)
 80 
 81 #ifdef CONFIG_LOCKDEP
 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)
 86 #else
 87 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
 88 #endif
 89 
 90 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
 91 {
 92         q->flags        = 0;
 93         q->private      = p;
 94         q->func         = default_wake_function;
 95 }
 96 
 97 static inline void
 98 init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func)
 99 {
100         q->flags        = 0;
101         q->private      = NULL;
102         q->func         = func;
103 }
104 
105 static inline int waitqueue_active(wait_queue_head_t *q)
106 {
107         return !list_empty(&q->task_list);
108 }
109 
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);
113 
114 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
115 {
116         list_add(&new->task_list, &head->task_list);
117 }
118 
119 /*
120  * Used for wake-one threads:
121  */
122 static inline void
123 __add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
124 {
125         wait->flags |= WQ_FLAG_EXCLUSIVE;
126         __add_wait_queue(q, wait);
127 }
128 
129 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
130                                          wait_queue_t *new)
131 {
132         list_add_tail(&new->task_list, &head->task_list);
133 }
134 
135 static inline void
136 __add_wait_queue_tail_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
137 {
138         wait->flags |= WQ_FLAG_EXCLUSIVE;
139         __add_wait_queue_tail(q, wait);
140 }
141 
142 static inline void
143 __remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old)
144 {
145         list_del(&old->task_list);
146 }
147 
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);
164 
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)
170 
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)
175 
176 /*
177  * Wakeup macros to be used to report events to the targets.
178  */
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))
187 
188 #define ___wait_cond_timeout(condition)                                 \
189 ({                                                                      \
190         bool __cond = (condition);                                      \
191         if (__cond && !__ret)                                           \
192                 __ret = 1;                                              \
193         __cond || !__ret;                                               \
194 })
195 
196 #define ___wait_is_interruptible(state)                                 \
197         (!__builtin_constant_p(state) ||                                \
198                 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE)  \
199 
200 /*
201  * The below macro ___wait_event() has an explicit shadow of the __ret
202  * variable when used from the wait_event_*() macros.
203  *
204  * This is so that both can use the ___wait_cond_timeout() construct
205  * to wrap the condition.
206  *
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
209  * otherwise.
210  */
211 
212 #define ___wait_event(wq, condition, state, exclusive, ret, cmd)        \
213 ({                                                                      \
214         __label__ __out;                                                \
215         wait_queue_t __wait;                                            \
216         long __ret = ret;       /* explicit shadow */                   \
217                                                                         \
218         INIT_LIST_HEAD(&__wait.task_list);                              \
219         if (exclusive)                                                  \
220                 __wait.flags = WQ_FLAG_EXCLUSIVE;                       \
221         else                                                            \
222                 __wait.flags = 0;                                       \
223                                                                         \
224         for (;;) {                                                      \
225                 long __int = prepare_to_wait_event(&wq, &__wait, state);\
226                                                                         \
227                 if (condition)                                          \
228                         break;                                          \
229                                                                         \
230                 if (___wait_is_interruptible(state) && __int) {         \
231                         __ret = __int;                                  \
232                         if (exclusive) {                                \
233                                 abort_exclusive_wait(&wq, &__wait,      \
234                                                      state, NULL);      \
235                                 goto __out;                             \
236                         }                                               \
237                         break;                                          \
238                 }                                                       \
239                                                                         \
240                 cmd;                                                    \
241         }                                                               \
242         finish_wait(&wq, &__wait);                                      \
243 __out:  __ret;                                                          \
244 })
245 
246 #define __wait_event(wq, condition)                                     \
247         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
248                             schedule())
249 
250 /**
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
254  *
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.
258  *
259  * wake_up() has to be called after changing any variable that could
260  * change the result of the wait condition.
261  */
262 #define wait_event(wq, condition)                                       \
263 do {                                                                    \
264         might_sleep();                                                  \
265         if (condition)                                                  \
266                 break;                                                  \
267         __wait_event(wq, condition);                                    \
268 } while (0)
269 
270 #define __io_wait_event(wq, condition)                                  \
271         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
272                             io_schedule())
273 
274 /*
275  * io_wait_event() -- like wait_event() but with io_schedule()
276  */
277 #define io_wait_event(wq, condition)                                    \
278 do {                                                                    \
279         might_sleep();                                                  \
280         if (condition)                                                  \
281                 break;                                                  \
282         __io_wait_event(wq, condition);                                 \
283 } while (0)
284 
285 #define __wait_event_freezable(wq, condition)                           \
286         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
287                             schedule(); try_to_freeze())
288 
289 /**
290  * wait_event - sleep (or freeze) until a condition gets true
291  * @wq: the waitqueue to wait on
292  * @condition: a C expression for the event to wait for
293  *
294  * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
295  * to system load) until the @condition evaluates to true. The
296  * @condition is checked each time the waitqueue @wq is woken up.
297  *
298  * wake_up() has to be called after changing any variable that could
299  * change the result of the wait condition.
300  */
301 #define wait_event_freezable(wq, condition)                             \
302 ({                                                                      \
303         int __ret = 0;                                                  \
304         might_sleep();                                                  \
305         if (!(condition))                                               \
306                 __ret = __wait_event_freezable(wq, condition);          \
307         __ret;                                                          \
308 })
309 
310 #define __wait_event_timeout(wq, condition, timeout)                    \
311         ___wait_event(wq, ___wait_cond_timeout(condition),              \
312                       TASK_UNINTERRUPTIBLE, 0, timeout,                 \
313                       __ret = schedule_timeout(__ret))
314 
315 /**
316  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
317  * @wq: the waitqueue to wait on
318  * @condition: a C expression for the event to wait for
319  * @timeout: timeout, in jiffies
320  *
321  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
322  * @condition evaluates to true. The @condition is checked each time
323  * the waitqueue @wq is woken up.
324  *
325  * wake_up() has to be called after changing any variable that could
326  * change the result of the wait condition.
327  *
328  * Returns:
329  * 0 if the @condition evaluated to %false after the @timeout elapsed,
330  * 1 if the @condition evaluated to %true after the @timeout elapsed,
331  * or the remaining jiffies (at least 1) if the @condition evaluated
332  * to %true before the @timeout elapsed.
333  */
334 #define wait_event_timeout(wq, condition, timeout)                      \
335 ({                                                                      \
336         long __ret = timeout;                                           \
337         might_sleep();                                                  \
338         if (!___wait_cond_timeout(condition))                           \
339                 __ret = __wait_event_timeout(wq, condition, timeout);   \
340         __ret;                                                          \
341 })
342 
343 #define __wait_event_freezable_timeout(wq, condition, timeout)          \
344         ___wait_event(wq, ___wait_cond_timeout(condition),              \
345                       TASK_INTERRUPTIBLE, 0, timeout,                   \
346                       __ret = schedule_timeout(__ret); try_to_freeze())
347 
348 /*
349  * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
350  * increasing load and is freezable.
351  */
352 #define wait_event_freezable_timeout(wq, condition, timeout)            \
353 ({                                                                      \
354         long __ret = timeout;                                           \
355         might_sleep();                                                  \
356         if (!___wait_cond_timeout(condition))                           \
357                 __ret = __wait_event_freezable_timeout(wq, condition, timeout); \
358         __ret;                                                          \
359 })
360 
361 #define __wait_event_cmd(wq, condition, cmd1, cmd2)                     \
362         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
363                             cmd1; schedule(); cmd2)
364 
365 /**
366  * wait_event_cmd - sleep until a condition gets true
367  * @wq: the waitqueue to wait on
368  * @condition: a C expression for the event to wait for
369  * @cmd1: the command will be executed before sleep
370  * @cmd2: the command will be executed after sleep
371  *
372  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
373  * @condition evaluates to true. The @condition is checked each time
374  * the waitqueue @wq is woken up.
375  *
376  * wake_up() has to be called after changing any variable that could
377  * change the result of the wait condition.
378  */
379 #define wait_event_cmd(wq, condition, cmd1, cmd2)                       \
380 do {                                                                    \
381         if (condition)                                                  \
382                 break;                                                  \
383         __wait_event_cmd(wq, condition, cmd1, cmd2);                    \
384 } while (0)
385 
386 #define __wait_event_interruptible(wq, condition)                       \
387         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
388                       schedule())
389 
390 /**
391  * wait_event_interruptible - sleep until a condition gets true
392  * @wq: the waitqueue to wait on
393  * @condition: a C expression for the event to wait for
394  *
395  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
396  * @condition evaluates to true or a signal is received.
397  * The @condition is checked each time the waitqueue @wq is woken up.
398  *
399  * wake_up() has to be called after changing any variable that could
400  * change the result of the wait condition.
401  *
402  * The function will return -ERESTARTSYS if it was interrupted by a
403  * signal and 0 if @condition evaluated to true.
404  */
405 #define wait_event_interruptible(wq, condition)                         \
406 ({                                                                      \
407         int __ret = 0;                                                  \
408         might_sleep();                                                  \
409         if (!(condition))                                               \
410                 __ret = __wait_event_interruptible(wq, condition);      \
411         __ret;                                                          \
412 })
413 
414 #define __wait_event_interruptible_timeout(wq, condition, timeout)      \
415         ___wait_event(wq, ___wait_cond_timeout(condition),              \
416                       TASK_INTERRUPTIBLE, 0, timeout,                   \
417                       __ret = schedule_timeout(__ret))
418 
419 /**
420  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
421  * @wq: the waitqueue to wait on
422  * @condition: a C expression for the event to wait for
423  * @timeout: timeout, in jiffies
424  *
425  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
426  * @condition evaluates to true or a signal is received.
427  * The @condition is checked each time the waitqueue @wq is woken up.
428  *
429  * wake_up() has to be called after changing any variable that could
430  * change the result of the wait condition.
431  *
432  * Returns:
433  * 0 if the @condition evaluated to %false after the @timeout elapsed,
434  * 1 if the @condition evaluated to %true after the @timeout elapsed,
435  * the remaining jiffies (at least 1) if the @condition evaluated
436  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
437  * interrupted by a signal.
438  */
439 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
440 ({                                                                      \
441         long __ret = timeout;                                           \
442         might_sleep();                                                  \
443         if (!___wait_cond_timeout(condition))                           \
444                 __ret = __wait_event_interruptible_timeout(wq,          \
445                                                 condition, timeout);    \
446         __ret;                                                          \
447 })
448 
449 #define __wait_event_hrtimeout(wq, condition, timeout, state)           \
450 ({                                                                      \
451         int __ret = 0;                                                  \
452         struct hrtimer_sleeper __t;                                     \
453                                                                         \
454         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
455                               HRTIMER_MODE_REL);                        \
456         hrtimer_init_sleeper(&__t, current);                            \
457         if ((timeout).tv64 != KTIME_MAX)                                \
458                 hrtimer_start_range_ns(&__t.timer, timeout,             \
459                                        current->timer_slack_ns,         \
460                                        HRTIMER_MODE_REL);               \
461                                                                         \
462         __ret = ___wait_event(wq, condition, state, 0, 0,               \
463                 if (!__t.task) {                                        \
464                         __ret = -ETIME;                                 \
465                         break;                                          \
466                 }                                                       \
467                 schedule());                                            \
468                                                                         \
469         hrtimer_cancel(&__t.timer);                                     \
470         destroy_hrtimer_on_stack(&__t.timer);                           \
471         __ret;                                                          \
472 })
473 
474 /**
475  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
476  * @wq: the waitqueue to wait on
477  * @condition: a C expression for the event to wait for
478  * @timeout: timeout, as a ktime_t
479  *
480  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
481  * @condition evaluates to true or a signal is received.
482  * The @condition is checked each time the waitqueue @wq is woken up.
483  *
484  * wake_up() has to be called after changing any variable that could
485  * change the result of the wait condition.
486  *
487  * The function returns 0 if @condition became true, or -ETIME if the timeout
488  * elapsed.
489  */
490 #define wait_event_hrtimeout(wq, condition, timeout)                    \
491 ({                                                                      \
492         int __ret = 0;                                                  \
493         might_sleep();                                                  \
494         if (!(condition))                                               \
495                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
496                                                TASK_UNINTERRUPTIBLE);   \
497         __ret;                                                          \
498 })
499 
500 /**
501  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
502  * @wq: the waitqueue to wait on
503  * @condition: a C expression for the event to wait for
504  * @timeout: timeout, as a ktime_t
505  *
506  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
507  * @condition evaluates to true or a signal is received.
508  * The @condition is checked each time the waitqueue @wq is woken up.
509  *
510  * wake_up() has to be called after changing any variable that could
511  * change the result of the wait condition.
512  *
513  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
514  * interrupted by a signal, or -ETIME if the timeout elapsed.
515  */
516 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
517 ({                                                                      \
518         long __ret = 0;                                                 \
519         might_sleep();                                                  \
520         if (!(condition))                                               \
521                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
522                                                TASK_INTERRUPTIBLE);     \
523         __ret;                                                          \
524 })
525 
526 #define __wait_event_interruptible_exclusive(wq, condition)             \
527         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
528                       schedule())
529 
530 #define wait_event_interruptible_exclusive(wq, condition)               \
531 ({                                                                      \
532         int __ret = 0;                                                  \
533         might_sleep();                                                  \
534         if (!(condition))                                               \
535                 __ret = __wait_event_interruptible_exclusive(wq, condition);\
536         __ret;                                                          \
537 })
538 
539 
540 #define __wait_event_freezable_exclusive(wq, condition)                 \
541         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
542                         schedule(); try_to_freeze())
543 
544 #define wait_event_freezable_exclusive(wq, condition)                   \
545 ({                                                                      \
546         int __ret = 0;                                                  \
547         might_sleep();                                                  \
548         if (!(condition))                                               \
549                 __ret = __wait_event_freezable_exclusive(wq, condition);\
550         __ret;                                                          \
551 })
552 
553 
554 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
555 ({                                                                      \
556         int __ret = 0;                                                  \
557         DEFINE_WAIT(__wait);                                            \
558         if (exclusive)                                                  \
559                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
560         do {                                                            \
561                 if (likely(list_empty(&__wait.task_list)))              \
562                         __add_wait_queue_tail(&(wq), &__wait);          \
563                 set_current_state(TASK_INTERRUPTIBLE);                  \
564                 if (signal_pending(current)) {                          \
565                         __ret = -ERESTARTSYS;                           \
566                         break;                                          \
567                 }                                                       \
568                 if (irq)                                                \
569                         spin_unlock_irq(&(wq).lock);                    \
570                 else                                                    \
571                         spin_unlock(&(wq).lock);                        \
572                 schedule();                                             \
573                 if (irq)                                                \
574                         spin_lock_irq(&(wq).lock);                      \
575                 else                                                    \
576                         spin_lock(&(wq).lock);                          \
577         } while (!(condition));                                         \
578         __remove_wait_queue(&(wq), &__wait);                            \
579         __set_current_state(TASK_RUNNING);                              \
580         __ret;                                                          \
581 })
582 
583 
584 /**
585  * wait_event_interruptible_locked - sleep until a condition gets true
586  * @wq: the waitqueue to wait on
587  * @condition: a C expression for the event to wait for
588  *
589  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
590  * @condition evaluates to true or a signal is received.
591  * The @condition is checked each time the waitqueue @wq is woken up.
592  *
593  * It must be called with wq.lock being held.  This spinlock is
594  * unlocked while sleeping but @condition testing is done while lock
595  * is held and when this macro exits the lock is held.
596  *
597  * The lock is locked/unlocked using spin_lock()/spin_unlock()
598  * functions which must match the way they are locked/unlocked outside
599  * of this macro.
600  *
601  * wake_up_locked() has to be called after changing any variable that could
602  * change the result of the wait condition.
603  *
604  * The function will return -ERESTARTSYS if it was interrupted by a
605  * signal and 0 if @condition evaluated to true.
606  */
607 #define wait_event_interruptible_locked(wq, condition)                  \
608         ((condition)                                                    \
609          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
610 
611 /**
612  * wait_event_interruptible_locked_irq - sleep until a condition gets true
613  * @wq: the waitqueue to wait on
614  * @condition: a C expression for the event to wait for
615  *
616  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
617  * @condition evaluates to true or a signal is received.
618  * The @condition is checked each time the waitqueue @wq is woken up.
619  *
620  * It must be called with wq.lock being held.  This spinlock is
621  * unlocked while sleeping but @condition testing is done while lock
622  * is held and when this macro exits the lock is held.
623  *
624  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
625  * functions which must match the way they are locked/unlocked outside
626  * of this macro.
627  *
628  * wake_up_locked() has to be called after changing any variable that could
629  * change the result of the wait condition.
630  *
631  * The function will return -ERESTARTSYS if it was interrupted by a
632  * signal and 0 if @condition evaluated to true.
633  */
634 #define wait_event_interruptible_locked_irq(wq, condition)              \
635         ((condition)                                                    \
636          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
637 
638 /**
639  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
640  * @wq: the waitqueue to wait on
641  * @condition: a C expression for the event to wait for
642  *
643  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
644  * @condition evaluates to true or a signal is received.
645  * The @condition is checked each time the waitqueue @wq is woken up.
646  *
647  * It must be called with wq.lock being held.  This spinlock is
648  * unlocked while sleeping but @condition testing is done while lock
649  * is held and when this macro exits the lock is held.
650  *
651  * The lock is locked/unlocked using spin_lock()/spin_unlock()
652  * functions which must match the way they are locked/unlocked outside
653  * of this macro.
654  *
655  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
656  * set thus when other process waits process on the list if this
657  * process is awaken further processes are not considered.
658  *
659  * wake_up_locked() has to be called after changing any variable that could
660  * change the result of the wait condition.
661  *
662  * The function will return -ERESTARTSYS if it was interrupted by a
663  * signal and 0 if @condition evaluated to true.
664  */
665 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
666         ((condition)                                                    \
667          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
668 
669 /**
670  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
671  * @wq: the waitqueue to wait on
672  * @condition: a C expression for the event to wait for
673  *
674  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
675  * @condition evaluates to true or a signal is received.
676  * The @condition is checked each time the waitqueue @wq is woken up.
677  *
678  * It must be called with wq.lock being held.  This spinlock is
679  * unlocked while sleeping but @condition testing is done while lock
680  * is held and when this macro exits the lock is held.
681  *
682  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
683  * functions which must match the way they are locked/unlocked outside
684  * of this macro.
685  *
686  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
687  * set thus when other process waits process on the list if this
688  * process is awaken further processes are not considered.
689  *
690  * wake_up_locked() has to be called after changing any variable that could
691  * change the result of the wait condition.
692  *
693  * The function will return -ERESTARTSYS if it was interrupted by a
694  * signal and 0 if @condition evaluated to true.
695  */
696 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
697         ((condition)                                                    \
698          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
699 
700 
701 #define __wait_event_killable(wq, condition)                            \
702         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
703 
704 /**
705  * wait_event_killable - sleep until a condition gets true
706  * @wq: the waitqueue to wait on
707  * @condition: a C expression for the event to wait for
708  *
709  * The process is put to sleep (TASK_KILLABLE) until the
710  * @condition evaluates to true or a signal is received.
711  * The @condition is checked each time the waitqueue @wq is woken up.
712  *
713  * wake_up() has to be called after changing any variable that could
714  * change the result of the wait condition.
715  *
716  * The function will return -ERESTARTSYS if it was interrupted by a
717  * signal and 0 if @condition evaluated to true.
718  */
719 #define wait_event_killable(wq, condition)                              \
720 ({                                                                      \
721         int __ret = 0;                                                  \
722         might_sleep();                                                  \
723         if (!(condition))                                               \
724                 __ret = __wait_event_killable(wq, condition);           \
725         __ret;                                                          \
726 })
727 
728 
729 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
730         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
731                             spin_unlock_irq(&lock);                     \
732                             cmd;                                        \
733                             schedule();                                 \
734                             spin_lock_irq(&lock))
735 
736 /**
737  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
738  *                           condition is checked under the lock. This
739  *                           is expected to be called with the lock
740  *                           taken.
741  * @wq: the waitqueue to wait on
742  * @condition: a C expression for the event to wait for
743  * @lock: a locked spinlock_t, which will be released before cmd
744  *        and schedule() and reacquired afterwards.
745  * @cmd: a command which is invoked outside the critical section before
746  *       sleep
747  *
748  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
749  * @condition evaluates to true. The @condition is checked each time
750  * the waitqueue @wq is woken up.
751  *
752  * wake_up() has to be called after changing any variable that could
753  * change the result of the wait condition.
754  *
755  * This is supposed to be called while holding the lock. The lock is
756  * dropped before invoking the cmd and going to sleep and is reacquired
757  * afterwards.
758  */
759 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
760 do {                                                                    \
761         if (condition)                                                  \
762                 break;                                                  \
763         __wait_event_lock_irq(wq, condition, lock, cmd);                \
764 } while (0)
765 
766 /**
767  * wait_event_lock_irq - sleep until a condition gets true. The
768  *                       condition is checked under the lock. This
769  *                       is expected to be called with the lock
770  *                       taken.
771  * @wq: the waitqueue to wait on
772  * @condition: a C expression for the event to wait for
773  * @lock: a locked spinlock_t, which will be released before schedule()
774  *        and reacquired afterwards.
775  *
776  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
777  * @condition evaluates to true. The @condition is checked each time
778  * the waitqueue @wq is woken up.
779  *
780  * wake_up() has to be called after changing any variable that could
781  * change the result of the wait condition.
782  *
783  * This is supposed to be called while holding the lock. The lock is
784  * dropped before going to sleep and is reacquired afterwards.
785  */
786 #define wait_event_lock_irq(wq, condition, lock)                        \
787 do {                                                                    \
788         if (condition)                                                  \
789                 break;                                                  \
790         __wait_event_lock_irq(wq, condition, lock, );                   \
791 } while (0)
792 
793 
794 #define __wait_event_interruptible_lock_irq(wq, condition, lock, cmd)   \
795         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
796                       spin_unlock_irq(&lock);                           \
797                       cmd;                                              \
798                       schedule();                                       \
799                       spin_lock_irq(&lock))
800 
801 /**
802  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
803  *              The condition is checked under the lock. This is expected to
804  *              be called with the lock taken.
805  * @wq: the waitqueue to wait on
806  * @condition: a C expression for the event to wait for
807  * @lock: a locked spinlock_t, which will be released before cmd and
808  *        schedule() and reacquired afterwards.
809  * @cmd: a command which is invoked outside the critical section before
810  *       sleep
811  *
812  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
813  * @condition evaluates to true or a signal is received. The @condition is
814  * checked each time the waitqueue @wq is woken up.
815  *
816  * wake_up() has to be called after changing any variable that could
817  * change the result of the wait condition.
818  *
819  * This is supposed to be called while holding the lock. The lock is
820  * dropped before invoking the cmd and going to sleep and is reacquired
821  * afterwards.
822  *
823  * The macro will return -ERESTARTSYS if it was interrupted by a signal
824  * and 0 if @condition evaluated to true.
825  */
826 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
827 ({                                                                      \
828         int __ret = 0;                                                  \
829         if (!(condition))                                               \
830                 __ret = __wait_event_interruptible_lock_irq(wq,         \
831                                                 condition, lock, cmd);  \
832         __ret;                                                          \
833 })
834 
835 /**
836  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
837  *              The condition is checked under the lock. This is expected
838  *              to be called with the lock taken.
839  * @wq: the waitqueue to wait on
840  * @condition: a C expression for the event to wait for
841  * @lock: a locked spinlock_t, which will be released before schedule()
842  *        and reacquired afterwards.
843  *
844  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
845  * @condition evaluates to true or signal is received. The @condition is
846  * checked each time the waitqueue @wq is woken up.
847  *
848  * wake_up() has to be called after changing any variable that could
849  * change the result of the wait condition.
850  *
851  * This is supposed to be called while holding the lock. The lock is
852  * dropped before going to sleep and is reacquired afterwards.
853  *
854  * The macro will return -ERESTARTSYS if it was interrupted by a signal
855  * and 0 if @condition evaluated to true.
856  */
857 #define wait_event_interruptible_lock_irq(wq, condition, lock)          \
858 ({                                                                      \
859         int __ret = 0;                                                  \
860         if (!(condition))                                               \
861                 __ret = __wait_event_interruptible_lock_irq(wq,         \
862                                                 condition, lock,);      \
863         __ret;                                                          \
864 })
865 
866 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
867                                                     lock, timeout)      \
868         ___wait_event(wq, ___wait_cond_timeout(condition),              \
869                       TASK_INTERRUPTIBLE, 0, timeout,                   \
870                       spin_unlock_irq(&lock);                           \
871                       __ret = schedule_timeout(__ret);                  \
872                       spin_lock_irq(&lock));
873 
874 /**
875  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
876  *              true or a timeout elapses. The condition is checked under
877  *              the lock. This is expected to be called with the lock taken.
878  * @wq: the waitqueue to wait on
879  * @condition: a C expression for the event to wait for
880  * @lock: a locked spinlock_t, which will be released before schedule()
881  *        and reacquired afterwards.
882  * @timeout: timeout, in jiffies
883  *
884  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
885  * @condition evaluates to true or signal is received. The @condition is
886  * checked each time the waitqueue @wq is woken up.
887  *
888  * wake_up() has to be called after changing any variable that could
889  * change the result of the wait condition.
890  *
891  * This is supposed to be called while holding the lock. The lock is
892  * dropped before going to sleep and is reacquired afterwards.
893  *
894  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
895  * was interrupted by a signal, and the remaining jiffies otherwise
896  * if the condition evaluated to true before the timeout elapsed.
897  */
898 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
899                                                   timeout)              \
900 ({                                                                      \
901         long __ret = timeout;                                           \
902         if (!___wait_cond_timeout(condition))                           \
903                 __ret = __wait_event_interruptible_lock_irq_timeout(    \
904                                         wq, condition, lock, timeout);  \
905         __ret;                                                          \
906 })
907 
908 /*
909  * Waitqueues which are removed from the waitqueue_head at wakeup time
910  */
911 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
912 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
913 long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state);
914 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
915 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key);
916 long wait_woken(wait_queue_t *wait, unsigned mode, long timeout);
917 int woken_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
918 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
919 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
920 
921 #define DEFINE_WAIT_FUNC(name, function)                                \
922         wait_queue_t name = {                                           \
923                 .private        = current,                              \
924                 .func           = function,                             \
925                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
926         }
927 
928 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
929 
930 #define DEFINE_WAIT_BIT(name, word, bit)                                \
931         struct wait_bit_queue name = {                                  \
932                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
933                 .wait   = {                                             \
934                         .private        = current,                      \
935                         .func           = wake_bit_function,            \
936                         .task_list      =                               \
937                                 LIST_HEAD_INIT((name).wait.task_list),  \
938                 },                                                      \
939         }
940 
941 #define init_wait(wait)                                                 \
942         do {                                                            \
943                 (wait)->private = current;                              \
944                 (wait)->func = autoremove_wake_function;                \
945                 INIT_LIST_HEAD(&(wait)->task_list);                     \
946                 (wait)->flags = 0;                                      \
947         } while (0)
948 
949 
950 extern int bit_wait(struct wait_bit_key *);
951 extern int bit_wait_io(struct wait_bit_key *);
952 extern int bit_wait_timeout(struct wait_bit_key *);
953 extern int bit_wait_io_timeout(struct wait_bit_key *);
954 
955 /**
956  * wait_on_bit - wait for a bit to be cleared
957  * @word: the word being waited on, a kernel virtual address
958  * @bit: the bit of the word being waited on
959  * @mode: the task state to sleep in
960  *
961  * There is a standard hashed waitqueue table for generic use. This
962  * is the part of the hashtable's accessor API that waits on a bit.
963  * For instance, if one were to have waiters on a bitflag, one would
964  * call wait_on_bit() in threads waiting for the bit to clear.
965  * One uses wait_on_bit() where one is waiting for the bit to clear,
966  * but has no intention of setting it.
967  * Returned value will be zero if the bit was cleared, or non-zero
968  * if the process received a signal and the mode permitted wakeup
969  * on that signal.
970  */
971 static inline int
972 wait_on_bit(void *word, int bit, unsigned mode)
973 {
974         might_sleep();
975         if (!test_bit(bit, word))
976                 return 0;
977         return out_of_line_wait_on_bit(word, bit,
978                                        bit_wait,
979                                        mode);
980 }
981 
982 /**
983  * wait_on_bit_io - wait for a bit to be cleared
984  * @word: the word being waited on, a kernel virtual address
985  * @bit: the bit of the word being waited on
986  * @mode: the task state to sleep in
987  *
988  * Use the standard hashed waitqueue table to wait for a bit
989  * to be cleared.  This is similar to wait_on_bit(), but calls
990  * io_schedule() instead of schedule() for the actual waiting.
991  *
992  * Returned value will be zero if the bit was cleared, or non-zero
993  * if the process received a signal and the mode permitted wakeup
994  * on that signal.
995  */
996 static inline int
997 wait_on_bit_io(void *word, int bit, unsigned mode)
998 {
999         might_sleep();
1000         if (!test_bit(bit, word))
1001                 return 0;
1002         return out_of_line_wait_on_bit(word, bit,
1003                                        bit_wait_io,
1004                                        mode);
1005 }
1006 
1007 /**
1008  * wait_on_bit_timeout - wait for a bit to be cleared or a timeout elapses
1009  * @word: the word being waited on, a kernel virtual address
1010  * @bit: the bit of the word being waited on
1011  * @mode: the task state to sleep in
1012  * @timeout: timeout, in jiffies
1013  *
1014  * Use the standard hashed waitqueue table to wait for a bit
1015  * to be cleared. This is similar to wait_on_bit(), except also takes a
1016  * timeout parameter.
1017  *
1018  * Returned value will be zero if the bit was cleared before the
1019  * @timeout elapsed, or non-zero if the @timeout elapsed or process
1020  * received a signal and the mode permitted wakeup on that signal.
1021  */
1022 static inline int
1023 wait_on_bit_timeout(void *word, int bit, unsigned mode, unsigned long timeout)
1024 {
1025         might_sleep();
1026         if (!test_bit(bit, word))
1027                 return 0;
1028         return out_of_line_wait_on_bit_timeout(word, bit,
1029                                                bit_wait_timeout,
1030                                                mode, timeout);
1031 }
1032 
1033 /**
1034  * wait_on_bit_action - wait for a bit to be cleared
1035  * @word: the word being waited on, a kernel virtual address
1036  * @bit: the bit of the word being waited on
1037  * @action: the function used to sleep, which may take special actions
1038  * @mode: the task state to sleep in
1039  *
1040  * Use the standard hashed waitqueue table to wait for a bit
1041  * to be cleared, and allow the waiting action to be specified.
1042  * This is like wait_on_bit() but allows fine control of how the waiting
1043  * is done.
1044  *
1045  * Returned value will be zero if the bit was cleared, or non-zero
1046  * if the process received a signal and the mode permitted wakeup
1047  * on that signal.
1048  */
1049 static inline int
1050 wait_on_bit_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
1051 {
1052         might_sleep();
1053         if (!test_bit(bit, word))
1054                 return 0;
1055         return out_of_line_wait_on_bit(word, bit, action, mode);
1056 }
1057 
1058 /**
1059  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
1060  * @word: the word being waited on, a kernel virtual address
1061  * @bit: the bit of the word being waited on
1062  * @mode: the task state to sleep in
1063  *
1064  * There is a standard hashed waitqueue table for generic use. This
1065  * is the part of the hashtable's accessor API that waits on a bit
1066  * when one intends to set it, for instance, trying to lock bitflags.
1067  * For instance, if one were to have waiters trying to set bitflag
1068  * and waiting for it to clear before setting it, one would call
1069  * wait_on_bit() in threads waiting to be able to set the bit.
1070  * One uses wait_on_bit_lock() where one is waiting for the bit to
1071  * clear with the intention of setting it, and when done, clearing it.
1072  *
1073  * Returns zero if the bit was (eventually) found to be clear and was
1074  * set.  Returns non-zero if a signal was delivered to the process and
1075  * the @mode allows that signal to wake the process.
1076  */
1077 static inline int
1078 wait_on_bit_lock(void *word, int bit, unsigned mode)
1079 {
1080         might_sleep();
1081         if (!test_and_set_bit(bit, word))
1082                 return 0;
1083         return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode);
1084 }
1085 
1086 /**
1087  * wait_on_bit_lock_io - wait for a bit to be cleared, when wanting to set it
1088  * @word: the word being waited on, a kernel virtual address
1089  * @bit: the bit of the word being waited on
1090  * @mode: the task state to sleep in
1091  *
1092  * Use the standard hashed waitqueue table to wait for a bit
1093  * to be cleared and then to atomically set it.  This is similar
1094  * to wait_on_bit(), but calls io_schedule() instead of schedule()
1095  * for the actual waiting.
1096  *
1097  * Returns zero if the bit was (eventually) found to be clear and was
1098  * set.  Returns non-zero if a signal was delivered to the process and
1099  * the @mode allows that signal to wake the process.
1100  */
1101 static inline int
1102 wait_on_bit_lock_io(void *word, int bit, unsigned mode)
1103 {
1104         might_sleep();
1105         if (!test_and_set_bit(bit, word))
1106                 return 0;
1107         return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode);
1108 }
1109 
1110 /**
1111  * wait_on_bit_lock_action - wait for a bit to be cleared, when wanting to set it
1112  * @word: the word being waited on, a kernel virtual address
1113  * @bit: the bit of the word being waited on
1114  * @action: the function used to sleep, which may take special actions
1115  * @mode: the task state to sleep in
1116  *
1117  * Use the standard hashed waitqueue table to wait for a bit
1118  * to be cleared and then to set it, and allow the waiting action
1119  * to be specified.
1120  * This is like wait_on_bit() but allows fine control of how the waiting
1121  * is done.
1122  *
1123  * Returns zero if the bit was (eventually) found to be clear and was
1124  * set.  Returns non-zero if a signal was delivered to the process and
1125  * the @mode allows that signal to wake the process.
1126  */
1127 static inline int
1128 wait_on_bit_lock_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
1129 {
1130         might_sleep();
1131         if (!test_and_set_bit(bit, word))
1132                 return 0;
1133         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
1134 }
1135 
1136 /**
1137  * wait_on_atomic_t - Wait for an atomic_t to become 0
1138  * @val: The atomic value being waited on, a kernel virtual address
1139  * @action: the function used to sleep, which may take special actions
1140  * @mode: the task state to sleep in
1141  *
1142  * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
1143  * the purpose of getting a waitqueue, but we set the key to a bit number
1144  * outside of the target 'word'.
1145  */
1146 static inline
1147 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
1148 {
1149         might_sleep();
1150         if (atomic_read(val) == 0)
1151                 return 0;
1152         return out_of_line_wait_on_atomic_t(val, action, mode);
1153 }
1154 
1155 #endif /* _LINUX_WAIT_H */
1156 

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