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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_exclusive_cmd(wq, condition, cmd1, cmd2)           \
362         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 1, 0,  \
363                             cmd1; schedule(); cmd2)
364 /*
365  * Just like wait_event_cmd(), except it sets exclusive flag
366  */
367 #define wait_event_exclusive_cmd(wq, condition, cmd1, cmd2)             \
368 do {                                                                    \
369         if (condition)                                                  \
370                 break;                                                  \
371         __wait_event_exclusive_cmd(wq, condition, cmd1, cmd2);          \
372 } while (0)
373 
374 #define __wait_event_cmd(wq, condition, cmd1, cmd2)                     \
375         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
376                             cmd1; schedule(); cmd2)
377 
378 /**
379  * wait_event_cmd - sleep until a condition gets true
380  * @wq: the waitqueue to wait on
381  * @condition: a C expression for the event to wait for
382  * @cmd1: the command will be executed before sleep
383  * @cmd2: the command will be executed after sleep
384  *
385  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
386  * @condition evaluates to true. The @condition is checked each time
387  * the waitqueue @wq is woken up.
388  *
389  * wake_up() has to be called after changing any variable that could
390  * change the result of the wait condition.
391  */
392 #define wait_event_cmd(wq, condition, cmd1, cmd2)                       \
393 do {                                                                    \
394         if (condition)                                                  \
395                 break;                                                  \
396         __wait_event_cmd(wq, condition, cmd1, cmd2);                    \
397 } while (0)
398 
399 #define __wait_event_interruptible(wq, condition)                       \
400         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
401                       schedule())
402 
403 /**
404  * wait_event_interruptible - sleep until a condition gets true
405  * @wq: the waitqueue to wait on
406  * @condition: a C expression for the event to wait for
407  *
408  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
409  * @condition evaluates to true or a signal is received.
410  * The @condition is checked each time the waitqueue @wq is woken up.
411  *
412  * wake_up() has to be called after changing any variable that could
413  * change the result of the wait condition.
414  *
415  * The function will return -ERESTARTSYS if it was interrupted by a
416  * signal and 0 if @condition evaluated to true.
417  */
418 #define wait_event_interruptible(wq, condition)                         \
419 ({                                                                      \
420         int __ret = 0;                                                  \
421         might_sleep();                                                  \
422         if (!(condition))                                               \
423                 __ret = __wait_event_interruptible(wq, condition);      \
424         __ret;                                                          \
425 })
426 
427 #define __wait_event_interruptible_timeout(wq, condition, timeout)      \
428         ___wait_event(wq, ___wait_cond_timeout(condition),              \
429                       TASK_INTERRUPTIBLE, 0, timeout,                   \
430                       __ret = schedule_timeout(__ret))
431 
432 /**
433  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
434  * @wq: the waitqueue to wait on
435  * @condition: a C expression for the event to wait for
436  * @timeout: timeout, in jiffies
437  *
438  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
439  * @condition evaluates to true or a signal is received.
440  * The @condition is checked each time the waitqueue @wq is woken up.
441  *
442  * wake_up() has to be called after changing any variable that could
443  * change the result of the wait condition.
444  *
445  * Returns:
446  * 0 if the @condition evaluated to %false after the @timeout elapsed,
447  * 1 if the @condition evaluated to %true after the @timeout elapsed,
448  * the remaining jiffies (at least 1) if the @condition evaluated
449  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
450  * interrupted by a signal.
451  */
452 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
453 ({                                                                      \
454         long __ret = timeout;                                           \
455         might_sleep();                                                  \
456         if (!___wait_cond_timeout(condition))                           \
457                 __ret = __wait_event_interruptible_timeout(wq,          \
458                                                 condition, timeout);    \
459         __ret;                                                          \
460 })
461 
462 #define __wait_event_hrtimeout(wq, condition, timeout, state)           \
463 ({                                                                      \
464         int __ret = 0;                                                  \
465         struct hrtimer_sleeper __t;                                     \
466                                                                         \
467         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
468                               HRTIMER_MODE_REL);                        \
469         hrtimer_init_sleeper(&__t, current);                            \
470         if ((timeout).tv64 != KTIME_MAX)                                \
471                 hrtimer_start_range_ns(&__t.timer, timeout,             \
472                                        current->timer_slack_ns,         \
473                                        HRTIMER_MODE_REL);               \
474                                                                         \
475         __ret = ___wait_event(wq, condition, state, 0, 0,               \
476                 if (!__t.task) {                                        \
477                         __ret = -ETIME;                                 \
478                         break;                                          \
479                 }                                                       \
480                 schedule());                                            \
481                                                                         \
482         hrtimer_cancel(&__t.timer);                                     \
483         destroy_hrtimer_on_stack(&__t.timer);                           \
484         __ret;                                                          \
485 })
486 
487 /**
488  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
489  * @wq: the waitqueue to wait on
490  * @condition: a C expression for the event to wait for
491  * @timeout: timeout, as a ktime_t
492  *
493  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
494  * @condition evaluates to true or a signal is received.
495  * The @condition is checked each time the waitqueue @wq is woken up.
496  *
497  * wake_up() has to be called after changing any variable that could
498  * change the result of the wait condition.
499  *
500  * The function returns 0 if @condition became true, or -ETIME if the timeout
501  * elapsed.
502  */
503 #define wait_event_hrtimeout(wq, condition, timeout)                    \
504 ({                                                                      \
505         int __ret = 0;                                                  \
506         might_sleep();                                                  \
507         if (!(condition))                                               \
508                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
509                                                TASK_UNINTERRUPTIBLE);   \
510         __ret;                                                          \
511 })
512 
513 /**
514  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
515  * @wq: the waitqueue to wait on
516  * @condition: a C expression for the event to wait for
517  * @timeout: timeout, as a ktime_t
518  *
519  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
520  * @condition evaluates to true or a signal is received.
521  * The @condition is checked each time the waitqueue @wq is woken up.
522  *
523  * wake_up() has to be called after changing any variable that could
524  * change the result of the wait condition.
525  *
526  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
527  * interrupted by a signal, or -ETIME if the timeout elapsed.
528  */
529 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
530 ({                                                                      \
531         long __ret = 0;                                                 \
532         might_sleep();                                                  \
533         if (!(condition))                                               \
534                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
535                                                TASK_INTERRUPTIBLE);     \
536         __ret;                                                          \
537 })
538 
539 #define __wait_event_interruptible_exclusive(wq, condition)             \
540         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
541                       schedule())
542 
543 #define wait_event_interruptible_exclusive(wq, condition)               \
544 ({                                                                      \
545         int __ret = 0;                                                  \
546         might_sleep();                                                  \
547         if (!(condition))                                               \
548                 __ret = __wait_event_interruptible_exclusive(wq, condition);\
549         __ret;                                                          \
550 })
551 
552 
553 #define __wait_event_freezable_exclusive(wq, condition)                 \
554         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
555                         schedule(); try_to_freeze())
556 
557 #define wait_event_freezable_exclusive(wq, condition)                   \
558 ({                                                                      \
559         int __ret = 0;                                                  \
560         might_sleep();                                                  \
561         if (!(condition))                                               \
562                 __ret = __wait_event_freezable_exclusive(wq, condition);\
563         __ret;                                                          \
564 })
565 
566 
567 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
568 ({                                                                      \
569         int __ret = 0;                                                  \
570         DEFINE_WAIT(__wait);                                            \
571         if (exclusive)                                                  \
572                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
573         do {                                                            \
574                 if (likely(list_empty(&__wait.task_list)))              \
575                         __add_wait_queue_tail(&(wq), &__wait);          \
576                 set_current_state(TASK_INTERRUPTIBLE);                  \
577                 if (signal_pending(current)) {                          \
578                         __ret = -ERESTARTSYS;                           \
579                         break;                                          \
580                 }                                                       \
581                 if (irq)                                                \
582                         spin_unlock_irq(&(wq).lock);                    \
583                 else                                                    \
584                         spin_unlock(&(wq).lock);                        \
585                 schedule();                                             \
586                 if (irq)                                                \
587                         spin_lock_irq(&(wq).lock);                      \
588                 else                                                    \
589                         spin_lock(&(wq).lock);                          \
590         } while (!(condition));                                         \
591         __remove_wait_queue(&(wq), &__wait);                            \
592         __set_current_state(TASK_RUNNING);                              \
593         __ret;                                                          \
594 })
595 
596 
597 /**
598  * wait_event_interruptible_locked - sleep until a condition gets true
599  * @wq: the waitqueue to wait on
600  * @condition: a C expression for the event to wait for
601  *
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.
605  *
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.
609  *
610  * The lock is locked/unlocked using spin_lock()/spin_unlock()
611  * functions which must match the way they are locked/unlocked outside
612  * of this macro.
613  *
614  * wake_up_locked() has to be called after changing any variable that could
615  * change the result of the wait condition.
616  *
617  * The function will return -ERESTARTSYS if it was interrupted by a
618  * signal and 0 if @condition evaluated to true.
619  */
620 #define wait_event_interruptible_locked(wq, condition)                  \
621         ((condition)                                                    \
622          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
623 
624 /**
625  * wait_event_interruptible_locked_irq - sleep until a condition gets true
626  * @wq: the waitqueue to wait on
627  * @condition: a C expression for the event to wait for
628  *
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.
632  *
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.
636  *
637  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
638  * functions which must match the way they are locked/unlocked outside
639  * of this macro.
640  *
641  * wake_up_locked() has to be called after changing any variable that could
642  * change the result of the wait condition.
643  *
644  * The function will return -ERESTARTSYS if it was interrupted by a
645  * signal and 0 if @condition evaluated to true.
646  */
647 #define wait_event_interruptible_locked_irq(wq, condition)              \
648         ((condition)                                                    \
649          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
650 
651 /**
652  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
653  * @wq: the waitqueue to wait on
654  * @condition: a C expression for the event to wait for
655  *
656  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
657  * @condition evaluates to true or a signal is received.
658  * The @condition is checked each time the waitqueue @wq is woken up.
659  *
660  * It must be called with wq.lock being held.  This spinlock is
661  * unlocked while sleeping but @condition testing is done while lock
662  * is held and when this macro exits the lock is held.
663  *
664  * The lock is locked/unlocked using spin_lock()/spin_unlock()
665  * functions which must match the way they are locked/unlocked outside
666  * of this macro.
667  *
668  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
669  * set thus when other process waits process on the list if this
670  * process is awaken further processes are not considered.
671  *
672  * wake_up_locked() has to be called after changing any variable that could
673  * change the result of the wait condition.
674  *
675  * The function will return -ERESTARTSYS if it was interrupted by a
676  * signal and 0 if @condition evaluated to true.
677  */
678 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
679         ((condition)                                                    \
680          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
681 
682 /**
683  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
684  * @wq: the waitqueue to wait on
685  * @condition: a C expression for the event to wait for
686  *
687  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
688  * @condition evaluates to true or a signal is received.
689  * The @condition is checked each time the waitqueue @wq is woken up.
690  *
691  * It must be called with wq.lock being held.  This spinlock is
692  * unlocked while sleeping but @condition testing is done while lock
693  * is held and when this macro exits the lock is held.
694  *
695  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
696  * functions which must match the way they are locked/unlocked outside
697  * of this macro.
698  *
699  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
700  * set thus when other process waits process on the list if this
701  * process is awaken further processes are not considered.
702  *
703  * wake_up_locked() has to be called after changing any variable that could
704  * change the result of the wait condition.
705  *
706  * The function will return -ERESTARTSYS if it was interrupted by a
707  * signal and 0 if @condition evaluated to true.
708  */
709 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
710         ((condition)                                                    \
711          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
712 
713 
714 #define __wait_event_killable(wq, condition)                            \
715         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
716 
717 /**
718  * wait_event_killable - sleep until a condition gets true
719  * @wq: the waitqueue to wait on
720  * @condition: a C expression for the event to wait for
721  *
722  * The process is put to sleep (TASK_KILLABLE) until the
723  * @condition evaluates to true or a signal is received.
724  * The @condition is checked each time the waitqueue @wq is woken up.
725  *
726  * wake_up() has to be called after changing any variable that could
727  * change the result of the wait condition.
728  *
729  * The function will return -ERESTARTSYS if it was interrupted by a
730  * signal and 0 if @condition evaluated to true.
731  */
732 #define wait_event_killable(wq, condition)                              \
733 ({                                                                      \
734         int __ret = 0;                                                  \
735         might_sleep();                                                  \
736         if (!(condition))                                               \
737                 __ret = __wait_event_killable(wq, condition);           \
738         __ret;                                                          \
739 })
740 
741 
742 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
743         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
744                             spin_unlock_irq(&lock);                     \
745                             cmd;                                        \
746                             schedule();                                 \
747                             spin_lock_irq(&lock))
748 
749 /**
750  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
751  *                           condition is checked under the lock. This
752  *                           is expected to be called with the lock
753  *                           taken.
754  * @wq: the waitqueue to wait on
755  * @condition: a C expression for the event to wait for
756  * @lock: a locked spinlock_t, which will be released before cmd
757  *        and schedule() and reacquired afterwards.
758  * @cmd: a command which is invoked outside the critical section before
759  *       sleep
760  *
761  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
762  * @condition evaluates to true. The @condition is checked each time
763  * the waitqueue @wq is woken up.
764  *
765  * wake_up() has to be called after changing any variable that could
766  * change the result of the wait condition.
767  *
768  * This is supposed to be called while holding the lock. The lock is
769  * dropped before invoking the cmd and going to sleep and is reacquired
770  * afterwards.
771  */
772 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
773 do {                                                                    \
774         if (condition)                                                  \
775                 break;                                                  \
776         __wait_event_lock_irq(wq, condition, lock, cmd);                \
777 } while (0)
778 
779 /**
780  * wait_event_lock_irq - sleep until a condition gets true. The
781  *                       condition is checked under the lock. This
782  *                       is expected to be called with the lock
783  *                       taken.
784  * @wq: the waitqueue to wait on
785  * @condition: a C expression for the event to wait for
786  * @lock: a locked spinlock_t, which will be released before schedule()
787  *        and reacquired afterwards.
788  *
789  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
790  * @condition evaluates to true. The @condition is checked each time
791  * the waitqueue @wq is woken up.
792  *
793  * wake_up() has to be called after changing any variable that could
794  * change the result of the wait condition.
795  *
796  * This is supposed to be called while holding the lock. The lock is
797  * dropped before going to sleep and is reacquired afterwards.
798  */
799 #define wait_event_lock_irq(wq, condition, lock)                        \
800 do {                                                                    \
801         if (condition)                                                  \
802                 break;                                                  \
803         __wait_event_lock_irq(wq, condition, lock, );                   \
804 } while (0)
805 
806 
807 #define __wait_event_interruptible_lock_irq(wq, condition, lock, cmd)   \
808         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
809                       spin_unlock_irq(&lock);                           \
810                       cmd;                                              \
811                       schedule();                                       \
812                       spin_lock_irq(&lock))
813 
814 /**
815  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
816  *              The condition is checked under the lock. This is expected to
817  *              be called with the lock taken.
818  * @wq: the waitqueue to wait on
819  * @condition: a C expression for the event to wait for
820  * @lock: a locked spinlock_t, which will be released before cmd and
821  *        schedule() and reacquired afterwards.
822  * @cmd: a command which is invoked outside the critical section before
823  *       sleep
824  *
825  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
826  * @condition evaluates to true or a signal is received. The @condition is
827  * checked each time the waitqueue @wq is woken up.
828  *
829  * wake_up() has to be called after changing any variable that could
830  * change the result of the wait condition.
831  *
832  * This is supposed to be called while holding the lock. The lock is
833  * dropped before invoking the cmd and going to sleep and is reacquired
834  * afterwards.
835  *
836  * The macro will return -ERESTARTSYS if it was interrupted by a signal
837  * and 0 if @condition evaluated to true.
838  */
839 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
840 ({                                                                      \
841         int __ret = 0;                                                  \
842         if (!(condition))                                               \
843                 __ret = __wait_event_interruptible_lock_irq(wq,         \
844                                                 condition, lock, cmd);  \
845         __ret;                                                          \
846 })
847 
848 /**
849  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
850  *              The condition is checked under the lock. This is expected
851  *              to be called with the lock taken.
852  * @wq: the waitqueue to wait on
853  * @condition: a C expression for the event to wait for
854  * @lock: a locked spinlock_t, which will be released before schedule()
855  *        and reacquired afterwards.
856  *
857  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
858  * @condition evaluates to true or signal is received. The @condition is
859  * checked each time the waitqueue @wq is woken up.
860  *
861  * wake_up() has to be called after changing any variable that could
862  * change the result of the wait condition.
863  *
864  * This is supposed to be called while holding the lock. The lock is
865  * dropped before going to sleep and is reacquired afterwards.
866  *
867  * The macro will return -ERESTARTSYS if it was interrupted by a signal
868  * and 0 if @condition evaluated to true.
869  */
870 #define wait_event_interruptible_lock_irq(wq, condition, lock)          \
871 ({                                                                      \
872         int __ret = 0;                                                  \
873         if (!(condition))                                               \
874                 __ret = __wait_event_interruptible_lock_irq(wq,         \
875                                                 condition, lock,);      \
876         __ret;                                                          \
877 })
878 
879 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
880                                                     lock, timeout)      \
881         ___wait_event(wq, ___wait_cond_timeout(condition),              \
882                       TASK_INTERRUPTIBLE, 0, timeout,                   \
883                       spin_unlock_irq(&lock);                           \
884                       __ret = schedule_timeout(__ret);                  \
885                       spin_lock_irq(&lock));
886 
887 /**
888  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
889  *              true or a timeout elapses. The condition is checked under
890  *              the lock. This is expected to be called with the lock taken.
891  * @wq: the waitqueue to wait on
892  * @condition: a C expression for the event to wait for
893  * @lock: a locked spinlock_t, which will be released before schedule()
894  *        and reacquired afterwards.
895  * @timeout: timeout, in jiffies
896  *
897  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
898  * @condition evaluates to true or signal is received. The @condition is
899  * checked each time the waitqueue @wq is woken up.
900  *
901  * wake_up() has to be called after changing any variable that could
902  * change the result of the wait condition.
903  *
904  * This is supposed to be called while holding the lock. The lock is
905  * dropped before going to sleep and is reacquired afterwards.
906  *
907  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
908  * was interrupted by a signal, and the remaining jiffies otherwise
909  * if the condition evaluated to true before the timeout elapsed.
910  */
911 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
912                                                   timeout)              \
913 ({                                                                      \
914         long __ret = timeout;                                           \
915         if (!___wait_cond_timeout(condition))                           \
916                 __ret = __wait_event_interruptible_lock_irq_timeout(    \
917                                         wq, condition, lock, timeout);  \
918         __ret;                                                          \
919 })
920 
921 /*
922  * Waitqueues which are removed from the waitqueue_head at wakeup time
923  */
924 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
925 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
926 long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state);
927 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
928 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key);
929 long wait_woken(wait_queue_t *wait, unsigned mode, long timeout);
930 int woken_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
931 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
932 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
933 
934 #define DEFINE_WAIT_FUNC(name, function)                                \
935         wait_queue_t name = {                                           \
936                 .private        = current,                              \
937                 .func           = function,                             \
938                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
939         }
940 
941 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
942 
943 #define DEFINE_WAIT_BIT(name, word, bit)                                \
944         struct wait_bit_queue name = {                                  \
945                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
946                 .wait   = {                                             \
947                         .private        = current,                      \
948                         .func           = wake_bit_function,            \
949                         .task_list      =                               \
950                                 LIST_HEAD_INIT((name).wait.task_list),  \
951                 },                                                      \
952         }
953 
954 #define init_wait(wait)                                                 \
955         do {                                                            \
956                 (wait)->private = current;                              \
957                 (wait)->func = autoremove_wake_function;                \
958                 INIT_LIST_HEAD(&(wait)->task_list);                     \
959                 (wait)->flags = 0;                                      \
960         } while (0)
961 
962 
963 extern int bit_wait(struct wait_bit_key *);
964 extern int bit_wait_io(struct wait_bit_key *);
965 extern int bit_wait_timeout(struct wait_bit_key *);
966 extern int bit_wait_io_timeout(struct wait_bit_key *);
967 
968 /**
969  * wait_on_bit - 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
973  *
974  * There is a standard hashed waitqueue table for generic use. This
975  * is the part of the hashtable's accessor API that waits on a bit.
976  * For instance, if one were to have waiters on a bitflag, one would
977  * call wait_on_bit() in threads waiting for the bit to clear.
978  * One uses wait_on_bit() where one is waiting for the bit to clear,
979  * but has no intention of setting it.
980  * Returned value will be zero if the bit was cleared, or non-zero
981  * if the process received a signal and the mode permitted wakeup
982  * on that signal.
983  */
984 static inline int
985 wait_on_bit(unsigned long *word, int bit, unsigned mode)
986 {
987         might_sleep();
988         if (!test_bit(bit, word))
989                 return 0;
990         return out_of_line_wait_on_bit(word, bit,
991                                        bit_wait,
992                                        mode);
993 }
994 
995 /**
996  * wait_on_bit_io - wait for a bit to be cleared
997  * @word: the word being waited on, a kernel virtual address
998  * @bit: the bit of the word being waited on
999  * @mode: the task state to sleep in
1000  *
1001  * Use the standard hashed waitqueue table to wait for a bit
1002  * to be cleared.  This is similar to wait_on_bit(), but calls
1003  * io_schedule() instead of schedule() for the actual waiting.
1004  *
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
1007  * on that signal.
1008  */
1009 static inline int
1010 wait_on_bit_io(unsigned long *word, int bit, unsigned mode)
1011 {
1012         might_sleep();
1013         if (!test_bit(bit, word))
1014                 return 0;
1015         return out_of_line_wait_on_bit(word, bit,
1016                                        bit_wait_io,
1017                                        mode);
1018 }
1019 
1020 /**
1021  * wait_on_bit_timeout - wait for a bit to be cleared or a timeout elapses
1022  * @word: the word being waited on, a kernel virtual address
1023  * @bit: the bit of the word being waited on
1024  * @mode: the task state to sleep in
1025  * @timeout: timeout, in jiffies
1026  *
1027  * Use the standard hashed waitqueue table to wait for a bit
1028  * to be cleared. This is similar to wait_on_bit(), except also takes a
1029  * timeout parameter.
1030  *
1031  * Returned value will be zero if the bit was cleared before the
1032  * @timeout elapsed, or non-zero if the @timeout elapsed or process
1033  * received a signal and the mode permitted wakeup on that signal.
1034  */
1035 static inline int
1036 wait_on_bit_timeout(unsigned long *word, int bit, unsigned mode,
1037                     unsigned long timeout)
1038 {
1039         might_sleep();
1040         if (!test_bit(bit, word))
1041                 return 0;
1042         return out_of_line_wait_on_bit_timeout(word, bit,
1043                                                bit_wait_timeout,
1044                                                mode, timeout);
1045 }
1046 
1047 /**
1048  * wait_on_bit_action - wait for a bit to be cleared
1049  * @word: the word being waited on, a kernel virtual address
1050  * @bit: the bit of the word being waited on
1051  * @action: the function used to sleep, which may take special actions
1052  * @mode: the task state to sleep in
1053  *
1054  * Use the standard hashed waitqueue table to wait for a bit
1055  * to be cleared, and allow the waiting action to be specified.
1056  * This is like wait_on_bit() but allows fine control of how the waiting
1057  * is done.
1058  *
1059  * Returned value will be zero if the bit was cleared, or non-zero
1060  * if the process received a signal and the mode permitted wakeup
1061  * on that signal.
1062  */
1063 static inline int
1064 wait_on_bit_action(unsigned long *word, int bit, wait_bit_action_f *action,
1065                    unsigned mode)
1066 {
1067         might_sleep();
1068         if (!test_bit(bit, word))
1069                 return 0;
1070         return out_of_line_wait_on_bit(word, bit, action, mode);
1071 }
1072 
1073 /**
1074  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
1075  * @word: the word being waited on, a kernel virtual address
1076  * @bit: the bit of the word being waited on
1077  * @mode: the task state to sleep in
1078  *
1079  * There is a standard hashed waitqueue table for generic use. This
1080  * is the part of the hashtable's accessor API that waits on a bit
1081  * when one intends to set it, for instance, trying to lock bitflags.
1082  * For instance, if one were to have waiters trying to set bitflag
1083  * and waiting for it to clear before setting it, one would call
1084  * wait_on_bit() in threads waiting to be able to set the bit.
1085  * One uses wait_on_bit_lock() where one is waiting for the bit to
1086  * clear with the intention of setting it, and when done, clearing it.
1087  *
1088  * Returns zero if the bit was (eventually) found to be clear and was
1089  * set.  Returns non-zero if a signal was delivered to the process and
1090  * the @mode allows that signal to wake the process.
1091  */
1092 static inline int
1093 wait_on_bit_lock(unsigned long *word, int bit, unsigned mode)
1094 {
1095         might_sleep();
1096         if (!test_and_set_bit(bit, word))
1097                 return 0;
1098         return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode);
1099 }
1100 
1101 /**
1102  * wait_on_bit_lock_io - wait for a bit to be cleared, when wanting to set it
1103  * @word: the word being waited on, a kernel virtual address
1104  * @bit: the bit of the word being waited on
1105  * @mode: the task state to sleep in
1106  *
1107  * Use the standard hashed waitqueue table to wait for a bit
1108  * to be cleared and then to atomically set it.  This is similar
1109  * to wait_on_bit(), but calls io_schedule() instead of schedule()
1110  * for the actual waiting.
1111  *
1112  * Returns zero if the bit was (eventually) found to be clear and was
1113  * set.  Returns non-zero if a signal was delivered to the process and
1114  * the @mode allows that signal to wake the process.
1115  */
1116 static inline int
1117 wait_on_bit_lock_io(unsigned long *word, int bit, unsigned mode)
1118 {
1119         might_sleep();
1120         if (!test_and_set_bit(bit, word))
1121                 return 0;
1122         return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode);
1123 }
1124 
1125 /**
1126  * wait_on_bit_lock_action - wait for a bit to be cleared, when wanting to set it
1127  * @word: the word being waited on, a kernel virtual address
1128  * @bit: the bit of the word being waited on
1129  * @action: the function used to sleep, which may take special actions
1130  * @mode: the task state to sleep in
1131  *
1132  * Use the standard hashed waitqueue table to wait for a bit
1133  * to be cleared and then to set it, and allow the waiting action
1134  * to be specified.
1135  * This is like wait_on_bit() but allows fine control of how the waiting
1136  * is done.
1137  *
1138  * Returns zero if the bit was (eventually) found to be clear and was
1139  * set.  Returns non-zero if a signal was delivered to the process and
1140  * the @mode allows that signal to wake the process.
1141  */
1142 static inline int
1143 wait_on_bit_lock_action(unsigned long *word, int bit, wait_bit_action_f *action,
1144                         unsigned mode)
1145 {
1146         might_sleep();
1147         if (!test_and_set_bit(bit, word))
1148                 return 0;
1149         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
1150 }
1151 
1152 /**
1153  * wait_on_atomic_t - Wait for an atomic_t to become 0
1154  * @val: The atomic value being waited on, a kernel virtual address
1155  * @action: the function used to sleep, which may take special actions
1156  * @mode: the task state to sleep in
1157  *
1158  * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
1159  * the purpose of getting a waitqueue, but we set the key to a bit number
1160  * outside of the target 'word'.
1161  */
1162 static inline
1163 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
1164 {
1165         might_sleep();
1166         if (atomic_read(val) == 0)
1167                 return 0;
1168         return out_of_line_wait_on_atomic_t(val, action, mode);
1169 }
1170 
1171 #endif /* _LINUX_WAIT_H */
1172 

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