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TOMOYO Linux Cross Reference
Linux/include/linux/wait.h

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  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 
 10 #include <asm/current.h>
 11 #include <uapi/linux/wait.h>
 12 
 13 typedef struct wait_queue_entry wait_queue_entry_t;
 14 
 15 typedef int (*wait_queue_func_t)(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key);
 16 int default_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key);
 17 
 18 /* wait_queue_entry::flags */
 19 #define WQ_FLAG_EXCLUSIVE       0x01
 20 #define WQ_FLAG_WOKEN           0x02
 21 
 22 /*
 23  * A single wait-queue entry structure:
 24  */
 25 struct wait_queue_entry {
 26         unsigned int            flags;
 27         void                    *private;
 28         wait_queue_func_t       func;
 29         struct list_head        entry;
 30 };
 31 
 32 struct wait_queue_head {
 33         spinlock_t              lock;
 34         struct list_head        head;
 35 };
 36 typedef struct wait_queue_head wait_queue_head_t;
 37 
 38 struct task_struct;
 39 
 40 /*
 41  * Macros for declaration and initialisaton of the datatypes
 42  */
 43 
 44 #define __WAITQUEUE_INITIALIZER(name, tsk) {                                    \
 45         .private        = tsk,                                                  \
 46         .func           = default_wake_function,                                \
 47         .entry          = { NULL, NULL } }
 48 
 49 #define DECLARE_WAITQUEUE(name, tsk)                                            \
 50         struct wait_queue_entry name = __WAITQUEUE_INITIALIZER(name, tsk)
 51 
 52 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                                   \
 53         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),                      \
 54         .head           = { &(name).head, &(name).head } }
 55 
 56 #define DECLARE_WAIT_QUEUE_HEAD(name) \
 57         struct wait_queue_head name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
 58 
 59 extern void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *);
 60 
 61 #define init_waitqueue_head(wq_head)                                            \
 62         do {                                                                    \
 63                 static struct lock_class_key __key;                             \
 64                                                                                 \
 65                 __init_waitqueue_head((wq_head), #wq_head, &__key);             \
 66         } while (0)
 67 
 68 #ifdef CONFIG_LOCKDEP
 69 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
 70         ({ init_waitqueue_head(&name); name; })
 71 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
 72         struct wait_queue_head name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
 73 #else
 74 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
 75 #endif
 76 
 77 static inline void init_waitqueue_entry(struct wait_queue_entry *wq_entry, struct task_struct *p)
 78 {
 79         wq_entry->flags         = 0;
 80         wq_entry->private       = p;
 81         wq_entry->func          = default_wake_function;
 82 }
 83 
 84 static inline void
 85 init_waitqueue_func_entry(struct wait_queue_entry *wq_entry, wait_queue_func_t func)
 86 {
 87         wq_entry->flags         = 0;
 88         wq_entry->private       = NULL;
 89         wq_entry->func          = func;
 90 }
 91 
 92 /**
 93  * waitqueue_active -- locklessly test for waiters on the queue
 94  * @wq_head: the waitqueue to test for waiters
 95  *
 96  * returns true if the wait list is not empty
 97  *
 98  * NOTE: this function is lockless and requires care, incorrect usage _will_
 99  * lead to sporadic and non-obvious failure.
100  *
101  * Use either while holding wait_queue_head::lock or when used for wakeups
102  * with an extra smp_mb() like:
103  *
104  *      CPU0 - waker                    CPU1 - waiter
105  *
106  *                                      for (;;) {
107  *      @cond = true;                     prepare_to_wait(&wq_head, &wait, state);
108  *      smp_mb();                         // smp_mb() from set_current_state()
109  *      if (waitqueue_active(wq_head))         if (@cond)
110  *        wake_up(wq_head);                      break;
111  *                                        schedule();
112  *                                      }
113  *                                      finish_wait(&wq_head, &wait);
114  *
115  * Because without the explicit smp_mb() it's possible for the
116  * waitqueue_active() load to get hoisted over the @cond store such that we'll
117  * observe an empty wait list while the waiter might not observe @cond.
118  *
119  * Also note that this 'optimization' trades a spin_lock() for an smp_mb(),
120  * which (when the lock is uncontended) are of roughly equal cost.
121  */
122 static inline int waitqueue_active(struct wait_queue_head *wq_head)
123 {
124         return !list_empty(&wq_head->head);
125 }
126 
127 /**
128  * wq_has_sleeper - check if there are any waiting processes
129  * @wq_head: wait queue head
130  *
131  * Returns true if wq_head has waiting processes
132  *
133  * Please refer to the comment for waitqueue_active.
134  */
135 static inline bool wq_has_sleeper(struct wait_queue_head *wq_head)
136 {
137         /*
138          * We need to be sure we are in sync with the
139          * add_wait_queue modifications to the wait queue.
140          *
141          * This memory barrier should be paired with one on the
142          * waiting side.
143          */
144         smp_mb();
145         return waitqueue_active(wq_head);
146 }
147 
148 extern void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
149 extern void add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
150 extern void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
151 
152 static inline void __add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
153 {
154         list_add(&wq_entry->entry, &wq_head->head);
155 }
156 
157 /*
158  * Used for wake-one threads:
159  */
160 static inline void
161 __add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
162 {
163         wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
164         __add_wait_queue(wq_head, wq_entry);
165 }
166 
167 static inline void __add_wait_queue_entry_tail(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
168 {
169         list_add_tail(&wq_entry->entry, &wq_head->head);
170 }
171 
172 static inline void
173 __add_wait_queue_entry_tail_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
174 {
175         wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
176         __add_wait_queue_entry_tail(wq_head, wq_entry);
177 }
178 
179 static inline void
180 __remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
181 {
182         list_del(&wq_entry->entry);
183 }
184 
185 void __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
186 void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
187 void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
188 void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr);
189 void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode, int nr);
190 
191 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
192 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
193 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
194 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL, 1)
195 #define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)
196 
197 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
198 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
199 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
200 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
201 
202 /*
203  * Wakeup macros to be used to report events to the targets.
204  */
205 #define wake_up_poll(x, m)                                                      \
206         __wake_up(x, TASK_NORMAL, 1, (void *) (m))
207 #define wake_up_locked_poll(x, m)                                               \
208         __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
209 #define wake_up_interruptible_poll(x, m)                                        \
210         __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
211 #define wake_up_interruptible_sync_poll(x, m)                                   \
212         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
213 
214 #define ___wait_cond_timeout(condition)                                         \
215 ({                                                                              \
216         bool __cond = (condition);                                              \
217         if (__cond && !__ret)                                                   \
218                 __ret = 1;                                                      \
219         __cond || !__ret;                                                       \
220 })
221 
222 #define ___wait_is_interruptible(state)                                         \
223         (!__builtin_constant_p(state) ||                                        \
224                 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE)          \
225 
226 extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags);
227 
228 /*
229  * The below macro ___wait_event() has an explicit shadow of the __ret
230  * variable when used from the wait_event_*() macros.
231  *
232  * This is so that both can use the ___wait_cond_timeout() construct
233  * to wrap the condition.
234  *
235  * The type inconsistency of the wait_event_*() __ret variable is also
236  * on purpose; we use long where we can return timeout values and int
237  * otherwise.
238  */
239 
240 #define ___wait_event(wq_head, condition, state, exclusive, ret, cmd)           \
241 ({                                                                              \
242         __label__ __out;                                                        \
243         struct wait_queue_entry __wq_entry;                                     \
244         long __ret = ret;       /* explicit shadow */                           \
245                                                                                 \
246         init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0);        \
247         for (;;) {                                                              \
248                 long __int = prepare_to_wait_event(&wq_head, &__wq_entry, state);\
249                                                                                 \
250                 if (condition)                                                  \
251                         break;                                                  \
252                                                                                 \
253                 if (___wait_is_interruptible(state) && __int) {                 \
254                         __ret = __int;                                          \
255                         goto __out;                                             \
256                 }                                                               \
257                                                                                 \
258                 cmd;                                                            \
259         }                                                                       \
260         finish_wait(&wq_head, &__wq_entry);                                     \
261 __out:  __ret;                                                                  \
262 })
263 
264 #define __wait_event(wq_head, condition)                                        \
265         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
266                             schedule())
267 
268 /**
269  * wait_event - sleep until a condition gets true
270  * @wq_head: the waitqueue to wait on
271  * @condition: a C expression for the event to wait for
272  *
273  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
274  * @condition evaluates to true. The @condition is checked each time
275  * the waitqueue @wq_head is woken up.
276  *
277  * wake_up() has to be called after changing any variable that could
278  * change the result of the wait condition.
279  */
280 #define wait_event(wq_head, condition)                                          \
281 do {                                                                            \
282         might_sleep();                                                          \
283         if (condition)                                                          \
284                 break;                                                          \
285         __wait_event(wq_head, condition);                                       \
286 } while (0)
287 
288 #define __io_wait_event(wq_head, condition)                                     \
289         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
290                             io_schedule())
291 
292 /*
293  * io_wait_event() -- like wait_event() but with io_schedule()
294  */
295 #define io_wait_event(wq_head, condition)                                       \
296 do {                                                                            \
297         might_sleep();                                                          \
298         if (condition)                                                          \
299                 break;                                                          \
300         __io_wait_event(wq_head, condition);                                    \
301 } while (0)
302 
303 #define __wait_event_freezable(wq_head, condition)                              \
304         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
305                             schedule(); try_to_freeze())
306 
307 /**
308  * wait_event_freezable - sleep (or freeze) until a condition gets true
309  * @wq_head: the waitqueue to wait on
310  * @condition: a C expression for the event to wait for
311  *
312  * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
313  * to system load) until the @condition evaluates to true. The
314  * @condition is checked each time the waitqueue @wq_head is woken up.
315  *
316  * wake_up() has to be called after changing any variable that could
317  * change the result of the wait condition.
318  */
319 #define wait_event_freezable(wq_head, condition)                                \
320 ({                                                                              \
321         int __ret = 0;                                                          \
322         might_sleep();                                                          \
323         if (!(condition))                                                       \
324                 __ret = __wait_event_freezable(wq_head, condition);             \
325         __ret;                                                                  \
326 })
327 
328 #define __wait_event_timeout(wq_head, condition, timeout)                       \
329         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
330                       TASK_UNINTERRUPTIBLE, 0, timeout,                         \
331                       __ret = schedule_timeout(__ret))
332 
333 /**
334  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
335  * @wq_head: the waitqueue to wait on
336  * @condition: a C expression for the event to wait for
337  * @timeout: timeout, in jiffies
338  *
339  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
340  * @condition evaluates to true. The @condition is checked each time
341  * the waitqueue @wq_head is woken up.
342  *
343  * wake_up() has to be called after changing any variable that could
344  * change the result of the wait condition.
345  *
346  * Returns:
347  * 0 if the @condition evaluated to %false after the @timeout elapsed,
348  * 1 if the @condition evaluated to %true after the @timeout elapsed,
349  * or the remaining jiffies (at least 1) if the @condition evaluated
350  * to %true before the @timeout elapsed.
351  */
352 #define wait_event_timeout(wq_head, condition, timeout)                         \
353 ({                                                                              \
354         long __ret = timeout;                                                   \
355         might_sleep();                                                          \
356         if (!___wait_cond_timeout(condition))                                   \
357                 __ret = __wait_event_timeout(wq_head, condition, timeout);      \
358         __ret;                                                                  \
359 })
360 
361 #define __wait_event_freezable_timeout(wq_head, condition, timeout)             \
362         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
363                       TASK_INTERRUPTIBLE, 0, timeout,                           \
364                       __ret = schedule_timeout(__ret); try_to_freeze())
365 
366 /*
367  * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
368  * increasing load and is freezable.
369  */
370 #define wait_event_freezable_timeout(wq_head, condition, timeout)               \
371 ({                                                                              \
372         long __ret = timeout;                                                   \
373         might_sleep();                                                          \
374         if (!___wait_cond_timeout(condition))                                   \
375                 __ret = __wait_event_freezable_timeout(wq_head, condition, timeout); \
376         __ret;                                                                  \
377 })
378 
379 #define __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2)              \
380         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 1, 0,     \
381                             cmd1; schedule(); cmd2)
382 /*
383  * Just like wait_event_cmd(), except it sets exclusive flag
384  */
385 #define wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2)                \
386 do {                                                                            \
387         if (condition)                                                          \
388                 break;                                                          \
389         __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2);             \
390 } while (0)
391 
392 #define __wait_event_cmd(wq_head, condition, cmd1, cmd2)                        \
393         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
394                             cmd1; schedule(); cmd2)
395 
396 /**
397  * wait_event_cmd - sleep until a condition gets true
398  * @wq_head: the waitqueue to wait on
399  * @condition: a C expression for the event to wait for
400  * @cmd1: the command will be executed before sleep
401  * @cmd2: the command will be executed after sleep
402  *
403  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
404  * @condition evaluates to true. The @condition is checked each time
405  * the waitqueue @wq_head is woken up.
406  *
407  * wake_up() has to be called after changing any variable that could
408  * change the result of the wait condition.
409  */
410 #define wait_event_cmd(wq_head, condition, cmd1, cmd2)                          \
411 do {                                                                            \
412         if (condition)                                                          \
413                 break;                                                          \
414         __wait_event_cmd(wq_head, condition, cmd1, cmd2);                       \
415 } while (0)
416 
417 #define __wait_event_interruptible(wq_head, condition)                          \
418         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
419                       schedule())
420 
421 /**
422  * wait_event_interruptible - sleep until a condition gets true
423  * @wq_head: the waitqueue to wait on
424  * @condition: a C expression for the event to wait for
425  *
426  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
427  * @condition evaluates to true or a signal is received.
428  * The @condition is checked each time the waitqueue @wq_head is woken up.
429  *
430  * wake_up() has to be called after changing any variable that could
431  * change the result of the wait condition.
432  *
433  * The function will return -ERESTARTSYS if it was interrupted by a
434  * signal and 0 if @condition evaluated to true.
435  */
436 #define wait_event_interruptible(wq_head, condition)                            \
437 ({                                                                              \
438         int __ret = 0;                                                          \
439         might_sleep();                                                          \
440         if (!(condition))                                                       \
441                 __ret = __wait_event_interruptible(wq_head, condition);         \
442         __ret;                                                                  \
443 })
444 
445 #define __wait_event_interruptible_timeout(wq_head, condition, timeout)         \
446         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
447                       TASK_INTERRUPTIBLE, 0, timeout,                           \
448                       __ret = schedule_timeout(__ret))
449 
450 /**
451  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
452  * @wq_head: the waitqueue to wait on
453  * @condition: a C expression for the event to wait for
454  * @timeout: timeout, in jiffies
455  *
456  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
457  * @condition evaluates to true or a signal is received.
458  * The @condition is checked each time the waitqueue @wq_head is woken up.
459  *
460  * wake_up() has to be called after changing any variable that could
461  * change the result of the wait condition.
462  *
463  * Returns:
464  * 0 if the @condition evaluated to %false after the @timeout elapsed,
465  * 1 if the @condition evaluated to %true after the @timeout elapsed,
466  * the remaining jiffies (at least 1) if the @condition evaluated
467  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
468  * interrupted by a signal.
469  */
470 #define wait_event_interruptible_timeout(wq_head, condition, timeout)           \
471 ({                                                                              \
472         long __ret = timeout;                                                   \
473         might_sleep();                                                          \
474         if (!___wait_cond_timeout(condition))                                   \
475                 __ret = __wait_event_interruptible_timeout(wq_head,             \
476                                                 condition, timeout);            \
477         __ret;                                                                  \
478 })
479 
480 #define __wait_event_hrtimeout(wq_head, condition, timeout, state)              \
481 ({                                                                              \
482         int __ret = 0;                                                          \
483         struct hrtimer_sleeper __t;                                             \
484                                                                                 \
485         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);   \
486         hrtimer_init_sleeper(&__t, current);                                    \
487         if ((timeout) != KTIME_MAX)                                             \
488                 hrtimer_start_range_ns(&__t.timer, timeout,                     \
489                                        current->timer_slack_ns,                 \
490                                        HRTIMER_MODE_REL);                       \
491                                                                                 \
492         __ret = ___wait_event(wq_head, condition, state, 0, 0,                  \
493                 if (!__t.task) {                                                \
494                         __ret = -ETIME;                                         \
495                         break;                                                  \
496                 }                                                               \
497                 schedule());                                                    \
498                                                                                 \
499         hrtimer_cancel(&__t.timer);                                             \
500         destroy_hrtimer_on_stack(&__t.timer);                                   \
501         __ret;                                                                  \
502 })
503 
504 /**
505  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
506  * @wq_head: the waitqueue to wait on
507  * @condition: a C expression for the event to wait for
508  * @timeout: timeout, as a ktime_t
509  *
510  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
511  * @condition evaluates to true or a signal is received.
512  * The @condition is checked each time the waitqueue @wq_head is woken up.
513  *
514  * wake_up() has to be called after changing any variable that could
515  * change the result of the wait condition.
516  *
517  * The function returns 0 if @condition became true, or -ETIME if the timeout
518  * elapsed.
519  */
520 #define wait_event_hrtimeout(wq_head, condition, timeout)                       \
521 ({                                                                              \
522         int __ret = 0;                                                          \
523         might_sleep();                                                          \
524         if (!(condition))                                                       \
525                 __ret = __wait_event_hrtimeout(wq_head, condition, timeout,     \
526                                                TASK_UNINTERRUPTIBLE);           \
527         __ret;                                                                  \
528 })
529 
530 /**
531  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
532  * @wq: the waitqueue to wait on
533  * @condition: a C expression for the event to wait for
534  * @timeout: timeout, as a ktime_t
535  *
536  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
537  * @condition evaluates to true or a signal is received.
538  * The @condition is checked each time the waitqueue @wq is woken up.
539  *
540  * wake_up() has to be called after changing any variable that could
541  * change the result of the wait condition.
542  *
543  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
544  * interrupted by a signal, or -ETIME if the timeout elapsed.
545  */
546 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)              \
547 ({                                                                              \
548         long __ret = 0;                                                         \
549         might_sleep();                                                          \
550         if (!(condition))                                                       \
551                 __ret = __wait_event_hrtimeout(wq, condition, timeout,          \
552                                                TASK_INTERRUPTIBLE);             \
553         __ret;                                                                  \
554 })
555 
556 #define __wait_event_interruptible_exclusive(wq, condition)                     \
557         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,                  \
558                       schedule())
559 
560 #define wait_event_interruptible_exclusive(wq, condition)                       \
561 ({                                                                              \
562         int __ret = 0;                                                          \
563         might_sleep();                                                          \
564         if (!(condition))                                                       \
565                 __ret = __wait_event_interruptible_exclusive(wq, condition);    \
566         __ret;                                                                  \
567 })
568 
569 #define __wait_event_killable_exclusive(wq, condition)                          \
570         ___wait_event(wq, condition, TASK_KILLABLE, 1, 0,                       \
571                       schedule())
572 
573 #define wait_event_killable_exclusive(wq, condition)                            \
574 ({                                                                              \
575         int __ret = 0;                                                          \
576         might_sleep();                                                          \
577         if (!(condition))                                                       \
578                 __ret = __wait_event_killable_exclusive(wq, condition);         \
579         __ret;                                                                  \
580 })
581 
582 
583 #define __wait_event_freezable_exclusive(wq, condition)                         \
584         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,                  \
585                         schedule(); try_to_freeze())
586 
587 #define wait_event_freezable_exclusive(wq, condition)                           \
588 ({                                                                              \
589         int __ret = 0;                                                          \
590         might_sleep();                                                          \
591         if (!(condition))                                                       \
592                 __ret = __wait_event_freezable_exclusive(wq, condition);        \
593         __ret;                                                                  \
594 })
595 
596 extern int do_wait_intr(wait_queue_head_t *, wait_queue_entry_t *);
597 extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *);
598 
599 #define __wait_event_interruptible_locked(wq, condition, exclusive, fn)         \
600 ({                                                                              \
601         int __ret;                                                              \
602         DEFINE_WAIT(__wait);                                                    \
603         if (exclusive)                                                          \
604                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                              \
605         do {                                                                    \
606                 __ret = fn(&(wq), &__wait);                                     \
607                 if (__ret)                                                      \
608                         break;                                                  \
609         } while (!(condition));                                                 \
610         __remove_wait_queue(&(wq), &__wait);                                    \
611         __set_current_state(TASK_RUNNING);                                      \
612         __ret;                                                                  \
613 })
614 
615 
616 /**
617  * wait_event_interruptible_locked - sleep until a condition gets true
618  * @wq: the waitqueue to wait on
619  * @condition: a C expression for the event to wait for
620  *
621  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
622  * @condition evaluates to true or a signal is received.
623  * The @condition is checked each time the waitqueue @wq is woken up.
624  *
625  * It must be called with wq.lock being held.  This spinlock is
626  * unlocked while sleeping but @condition testing is done while lock
627  * is held and when this macro exits the lock is held.
628  *
629  * The lock is locked/unlocked using spin_lock()/spin_unlock()
630  * functions which must match the way they are locked/unlocked outside
631  * of this macro.
632  *
633  * wake_up_locked() has to be called after changing any variable that could
634  * change the result of the wait condition.
635  *
636  * The function will return -ERESTARTSYS if it was interrupted by a
637  * signal and 0 if @condition evaluated to true.
638  */
639 #define wait_event_interruptible_locked(wq, condition)                          \
640         ((condition)                                                            \
641          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr))
642 
643 /**
644  * wait_event_interruptible_locked_irq - sleep until a condition gets true
645  * @wq: the waitqueue to wait on
646  * @condition: a C expression for the event to wait for
647  *
648  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
649  * @condition evaluates to true or a signal is received.
650  * The @condition is checked each time the waitqueue @wq is woken up.
651  *
652  * It must be called with wq.lock being held.  This spinlock is
653  * unlocked while sleeping but @condition testing is done while lock
654  * is held and when this macro exits the lock is held.
655  *
656  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
657  * functions which must match the way they are locked/unlocked outside
658  * of this macro.
659  *
660  * wake_up_locked() has to be called after changing any variable that could
661  * change the result of the wait condition.
662  *
663  * The function will return -ERESTARTSYS if it was interrupted by a
664  * signal and 0 if @condition evaluated to true.
665  */
666 #define wait_event_interruptible_locked_irq(wq, condition)                      \
667         ((condition)                                                            \
668          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr_irq))
669 
670 /**
671  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
672  * @wq: the waitqueue to wait on
673  * @condition: a C expression for the event to wait for
674  *
675  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
676  * @condition evaluates to true or a signal is received.
677  * The @condition is checked each time the waitqueue @wq is woken up.
678  *
679  * It must be called with wq.lock being held.  This spinlock is
680  * unlocked while sleeping but @condition testing is done while lock
681  * is held and when this macro exits the lock is held.
682  *
683  * The lock is locked/unlocked using spin_lock()/spin_unlock()
684  * functions which must match the way they are locked/unlocked outside
685  * of this macro.
686  *
687  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
688  * set thus when other process waits process on the list if this
689  * process is awaken further processes are not considered.
690  *
691  * wake_up_locked() has to be called after changing any variable that could
692  * change the result of the wait condition.
693  *
694  * The function will return -ERESTARTSYS if it was interrupted by a
695  * signal and 0 if @condition evaluated to true.
696  */
697 #define wait_event_interruptible_exclusive_locked(wq, condition)                \
698         ((condition)                                                            \
699          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr))
700 
701 /**
702  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
703  * @wq: the waitqueue to wait on
704  * @condition: a C expression for the event to wait for
705  *
706  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
707  * @condition evaluates to true or a signal is received.
708  * The @condition is checked each time the waitqueue @wq is woken up.
709  *
710  * It must be called with wq.lock being held.  This spinlock is
711  * unlocked while sleeping but @condition testing is done while lock
712  * is held and when this macro exits the lock is held.
713  *
714  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
715  * functions which must match the way they are locked/unlocked outside
716  * of this macro.
717  *
718  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
719  * set thus when other process waits process on the list if this
720  * process is awaken further processes are not considered.
721  *
722  * wake_up_locked() has to be called after changing any variable that could
723  * change the result of the wait condition.
724  *
725  * The function will return -ERESTARTSYS if it was interrupted by a
726  * signal and 0 if @condition evaluated to true.
727  */
728 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)            \
729         ((condition)                                                            \
730          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr_irq))
731 
732 
733 #define __wait_event_killable(wq, condition)                                    \
734         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
735 
736 /**
737  * wait_event_killable - sleep until a condition gets true
738  * @wq_head: the waitqueue to wait on
739  * @condition: a C expression for the event to wait for
740  *
741  * The process is put to sleep (TASK_KILLABLE) until the
742  * @condition evaluates to true or a signal is received.
743  * The @condition is checked each time the waitqueue @wq_head is woken up.
744  *
745  * wake_up() has to be called after changing any variable that could
746  * change the result of the wait condition.
747  *
748  * The function will return -ERESTARTSYS if it was interrupted by a
749  * signal and 0 if @condition evaluated to true.
750  */
751 #define wait_event_killable(wq_head, condition)                                 \
752 ({                                                                              \
753         int __ret = 0;                                                          \
754         might_sleep();                                                          \
755         if (!(condition))                                                       \
756                 __ret = __wait_event_killable(wq_head, condition);              \
757         __ret;                                                                  \
758 })
759 
760 #define __wait_event_killable_timeout(wq_head, condition, timeout)              \
761         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
762                       TASK_KILLABLE, 0, timeout,                                \
763                       __ret = schedule_timeout(__ret))
764 
765 /**
766  * wait_event_killable_timeout - sleep until a condition gets true or a timeout elapses
767  * @wq_head: the waitqueue to wait on
768  * @condition: a C expression for the event to wait for
769  * @timeout: timeout, in jiffies
770  *
771  * The process is put to sleep (TASK_KILLABLE) until the
772  * @condition evaluates to true or a kill signal is received.
773  * The @condition is checked each time the waitqueue @wq_head is woken up.
774  *
775  * wake_up() has to be called after changing any variable that could
776  * change the result of the wait condition.
777  *
778  * Returns:
779  * 0 if the @condition evaluated to %false after the @timeout elapsed,
780  * 1 if the @condition evaluated to %true after the @timeout elapsed,
781  * the remaining jiffies (at least 1) if the @condition evaluated
782  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
783  * interrupted by a kill signal.
784  *
785  * Only kill signals interrupt this process.
786  */
787 #define wait_event_killable_timeout(wq_head, condition, timeout)                \
788 ({                                                                              \
789         long __ret = timeout;                                                   \
790         might_sleep();                                                          \
791         if (!___wait_cond_timeout(condition))                                   \
792                 __ret = __wait_event_killable_timeout(wq_head,                  \
793                                                 condition, timeout);            \
794         __ret;                                                                  \
795 })
796 
797 
798 #define __wait_event_lock_irq(wq_head, condition, lock, cmd)                    \
799         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
800                             spin_unlock_irq(&lock);                             \
801                             cmd;                                                \
802                             schedule();                                         \
803                             spin_lock_irq(&lock))
804 
805 /**
806  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
807  *                           condition is checked under the lock. This
808  *                           is expected to be called with the lock
809  *                           taken.
810  * @wq_head: the waitqueue to wait on
811  * @condition: a C expression for the event to wait for
812  * @lock: a locked spinlock_t, which will be released before cmd
813  *        and schedule() and reacquired afterwards.
814  * @cmd: a command which is invoked outside the critical section before
815  *       sleep
816  *
817  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
818  * @condition evaluates to true. The @condition is checked each time
819  * the waitqueue @wq_head is woken up.
820  *
821  * wake_up() has to be called after changing any variable that could
822  * change the result of the wait condition.
823  *
824  * This is supposed to be called while holding the lock. The lock is
825  * dropped before invoking the cmd and going to sleep and is reacquired
826  * afterwards.
827  */
828 #define wait_event_lock_irq_cmd(wq_head, condition, lock, cmd)                  \
829 do {                                                                            \
830         if (condition)                                                          \
831                 break;                                                          \
832         __wait_event_lock_irq(wq_head, condition, lock, cmd);                   \
833 } while (0)
834 
835 /**
836  * wait_event_lock_irq - sleep until a condition gets true. The
837  *                       condition is checked under the lock. This
838  *                       is expected to be called with the lock
839  *                       taken.
840  * @wq_head: the waitqueue to wait on
841  * @condition: a C expression for the event to wait for
842  * @lock: a locked spinlock_t, which will be released before schedule()
843  *        and reacquired afterwards.
844  *
845  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
846  * @condition evaluates to true. The @condition is checked each time
847  * the waitqueue @wq_head is woken up.
848  *
849  * wake_up() has to be called after changing any variable that could
850  * change the result of the wait condition.
851  *
852  * This is supposed to be called while holding the lock. The lock is
853  * dropped before going to sleep and is reacquired afterwards.
854  */
855 #define wait_event_lock_irq(wq_head, condition, lock)                           \
856 do {                                                                            \
857         if (condition)                                                          \
858                 break;                                                          \
859         __wait_event_lock_irq(wq_head, condition, lock, );                      \
860 } while (0)
861 
862 
863 #define __wait_event_interruptible_lock_irq(wq_head, condition, lock, cmd)      \
864         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
865                       spin_unlock_irq(&lock);                                   \
866                       cmd;                                                      \
867                       schedule();                                               \
868                       spin_lock_irq(&lock))
869 
870 /**
871  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
872  *              The condition is checked under the lock. This is expected to
873  *              be called with the lock taken.
874  * @wq_head: the waitqueue to wait on
875  * @condition: a C expression for the event to wait for
876  * @lock: a locked spinlock_t, which will be released before cmd and
877  *        schedule() and reacquired afterwards.
878  * @cmd: a command which is invoked outside the critical section before
879  *       sleep
880  *
881  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
882  * @condition evaluates to true or a signal is received. The @condition is
883  * checked each time the waitqueue @wq_head is woken up.
884  *
885  * wake_up() has to be called after changing any variable that could
886  * change the result of the wait condition.
887  *
888  * This is supposed to be called while holding the lock. The lock is
889  * dropped before invoking the cmd and going to sleep and is reacquired
890  * afterwards.
891  *
892  * The macro will return -ERESTARTSYS if it was interrupted by a signal
893  * and 0 if @condition evaluated to true.
894  */
895 #define wait_event_interruptible_lock_irq_cmd(wq_head, condition, lock, cmd)    \
896 ({                                                                              \
897         int __ret = 0;                                                          \
898         if (!(condition))                                                       \
899                 __ret = __wait_event_interruptible_lock_irq(wq_head,            \
900                                                 condition, lock, cmd);          \
901         __ret;                                                                  \
902 })
903 
904 /**
905  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
906  *              The condition is checked under the lock. This is expected
907  *              to be called with the lock taken.
908  * @wq_head: the waitqueue to wait on
909  * @condition: a C expression for the event to wait for
910  * @lock: a locked spinlock_t, which will be released before schedule()
911  *        and reacquired afterwards.
912  *
913  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
914  * @condition evaluates to true or signal is received. The @condition is
915  * checked each time the waitqueue @wq_head is woken up.
916  *
917  * wake_up() has to be called after changing any variable that could
918  * change the result of the wait condition.
919  *
920  * This is supposed to be called while holding the lock. The lock is
921  * dropped before going to sleep and is reacquired afterwards.
922  *
923  * The macro will return -ERESTARTSYS if it was interrupted by a signal
924  * and 0 if @condition evaluated to true.
925  */
926 #define wait_event_interruptible_lock_irq(wq_head, condition, lock)             \
927 ({                                                                              \
928         int __ret = 0;                                                          \
929         if (!(condition))                                                       \
930                 __ret = __wait_event_interruptible_lock_irq(wq_head,            \
931                                                 condition, lock,);              \
932         __ret;                                                                  \
933 })
934 
935 #define __wait_event_interruptible_lock_irq_timeout(wq_head, condition,         \
936                                                     lock, timeout)              \
937         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
938                       TASK_INTERRUPTIBLE, 0, timeout,                           \
939                       spin_unlock_irq(&lock);                                   \
940                       __ret = schedule_timeout(__ret);                          \
941                       spin_lock_irq(&lock));
942 
943 /**
944  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
945  *              true or a timeout elapses. The condition is checked under
946  *              the lock. This is expected to be called with the lock taken.
947  * @wq_head: the waitqueue to wait on
948  * @condition: a C expression for the event to wait for
949  * @lock: a locked spinlock_t, which will be released before schedule()
950  *        and reacquired afterwards.
951  * @timeout: timeout, in jiffies
952  *
953  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
954  * @condition evaluates to true or signal is received. The @condition is
955  * checked each time the waitqueue @wq_head is woken up.
956  *
957  * wake_up() has to be called after changing any variable that could
958  * change the result of the wait condition.
959  *
960  * This is supposed to be called while holding the lock. The lock is
961  * dropped before going to sleep and is reacquired afterwards.
962  *
963  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
964  * was interrupted by a signal, and the remaining jiffies otherwise
965  * if the condition evaluated to true before the timeout elapsed.
966  */
967 #define wait_event_interruptible_lock_irq_timeout(wq_head, condition, lock,     \
968                                                   timeout)                      \
969 ({                                                                              \
970         long __ret = timeout;                                                   \
971         if (!___wait_cond_timeout(condition))                                   \
972                 __ret = __wait_event_interruptible_lock_irq_timeout(            \
973                                         wq_head, condition, lock, timeout);     \
974         __ret;                                                                  \
975 })
976 
977 /*
978  * Waitqueues which are removed from the waitqueue_head at wakeup time
979  */
980 void prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
981 void prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
982 long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
983 void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
984 long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout);
985 int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
986 int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
987 
988 #define DEFINE_WAIT_FUNC(name, function)                                        \
989         struct wait_queue_entry name = {                                        \
990                 .private        = current,                                      \
991                 .func           = function,                                     \
992                 .entry          = LIST_HEAD_INIT((name).entry),                 \
993         }
994 
995 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
996 
997 #define init_wait(wait)                                                         \
998         do {                                                                    \
999                 (wait)->private = current;                                      \
1000                 (wait)->func = autoremove_wake_function;                        \
1001                 INIT_LIST_HEAD(&(wait)->entry);                                 \
1002                 (wait)->flags = 0;                                              \
1003         } while (0)
1004 
1005 #endif /* _LINUX_WAIT_H */
1006 

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