Version:  2.0.40 2.2.26 2.4.37 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17

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 struct __wait_queue {
 17         unsigned int            flags;
 18 #define WQ_FLAG_EXCLUSIVE       0x01
 19         void                    *private;
 20         wait_queue_func_t       func;
 21         struct list_head        task_list;
 22 };
 23 
 24 struct wait_bit_key {
 25         void                    *flags;
 26         int                     bit_nr;
 27 #define WAIT_ATOMIC_T_BIT_NR    -1
 28         unsigned long           private;
 29 };
 30 
 31 struct wait_bit_queue {
 32         struct wait_bit_key     key;
 33         wait_queue_t            wait;
 34 };
 35 
 36 struct __wait_queue_head {
 37         spinlock_t              lock;
 38         struct list_head        task_list;
 39 };
 40 typedef struct __wait_queue_head wait_queue_head_t;
 41 
 42 struct task_struct;
 43 
 44 /*
 45  * Macros for declaration and initialisaton of the datatypes
 46  */
 47 
 48 #define __WAITQUEUE_INITIALIZER(name, tsk) {                            \
 49         .private        = tsk,                                          \
 50         .func           = default_wake_function,                        \
 51         .task_list      = { NULL, NULL } }
 52 
 53 #define DECLARE_WAITQUEUE(name, tsk)                                    \
 54         wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
 55 
 56 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                           \
 57         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),              \
 58         .task_list      = { &(name).task_list, &(name).task_list } }
 59 
 60 #define DECLARE_WAIT_QUEUE_HEAD(name) \
 61         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
 62 
 63 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)                           \
 64         { .flags = word, .bit_nr = bit, }
 65 
 66 #define __WAIT_ATOMIC_T_KEY_INITIALIZER(p)                              \
 67         { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }
 68 
 69 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
 70 
 71 #define init_waitqueue_head(q)                          \
 72         do {                                            \
 73                 static struct lock_class_key __key;     \
 74                                                         \
 75                 __init_waitqueue_head((q), #q, &__key); \
 76         } while (0)
 77 
 78 #ifdef CONFIG_LOCKDEP
 79 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
 80         ({ init_waitqueue_head(&name); name; })
 81 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
 82         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
 83 #else
 84 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
 85 #endif
 86 
 87 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
 88 {
 89         q->flags        = 0;
 90         q->private      = p;
 91         q->func         = default_wake_function;
 92 }
 93 
 94 static inline void
 95 init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func)
 96 {
 97         q->flags        = 0;
 98         q->private      = NULL;
 99         q->func         = func;
100 }
101 
102 static inline int waitqueue_active(wait_queue_head_t *q)
103 {
104         return !list_empty(&q->task_list);
105 }
106 
107 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
108 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
109 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
110 
111 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
112 {
113         list_add(&new->task_list, &head->task_list);
114 }
115 
116 /*
117  * Used for wake-one threads:
118  */
119 static inline void
120 __add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
121 {
122         wait->flags |= WQ_FLAG_EXCLUSIVE;
123         __add_wait_queue(q, wait);
124 }
125 
126 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
127                                          wait_queue_t *new)
128 {
129         list_add_tail(&new->task_list, &head->task_list);
130 }
131 
132 static inline void
133 __add_wait_queue_tail_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
134 {
135         wait->flags |= WQ_FLAG_EXCLUSIVE;
136         __add_wait_queue_tail(q, wait);
137 }
138 
139 static inline void
140 __remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old)
141 {
142         list_del(&old->task_list);
143 }
144 
145 typedef int wait_bit_action_f(struct wait_bit_key *);
146 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
147 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
148 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
149 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
150 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
151 void __wake_up_bit(wait_queue_head_t *, void *, int);
152 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
153 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
154 void wake_up_bit(void *, int);
155 void wake_up_atomic_t(atomic_t *);
156 int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned);
157 int out_of_line_wait_on_bit_lock(void *, int, wait_bit_action_f *, unsigned);
158 int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned);
159 wait_queue_head_t *bit_waitqueue(void *, int);
160 
161 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
162 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
163 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
164 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL, 1)
165 #define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)
166 
167 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
168 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
169 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
170 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
171 
172 /*
173  * Wakeup macros to be used to report events to the targets.
174  */
175 #define wake_up_poll(x, m)                                              \
176         __wake_up(x, TASK_NORMAL, 1, (void *) (m))
177 #define wake_up_locked_poll(x, m)                                       \
178         __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
179 #define wake_up_interruptible_poll(x, m)                                \
180         __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
181 #define wake_up_interruptible_sync_poll(x, m)                           \
182         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
183 
184 #define ___wait_cond_timeout(condition)                                 \
185 ({                                                                      \
186         bool __cond = (condition);                                      \
187         if (__cond && !__ret)                                           \
188                 __ret = 1;                                              \
189         __cond || !__ret;                                               \
190 })
191 
192 #define ___wait_is_interruptible(state)                                 \
193         (!__builtin_constant_p(state) ||                                \
194                 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE)  \
195 
196 /*
197  * The below macro ___wait_event() has an explicit shadow of the __ret
198  * variable when used from the wait_event_*() macros.
199  *
200  * This is so that both can use the ___wait_cond_timeout() construct
201  * to wrap the condition.
202  *
203  * The type inconsistency of the wait_event_*() __ret variable is also
204  * on purpose; we use long where we can return timeout values and int
205  * otherwise.
206  */
207 
208 #define ___wait_event(wq, condition, state, exclusive, ret, cmd)        \
209 ({                                                                      \
210         __label__ __out;                                                \
211         wait_queue_t __wait;                                            \
212         long __ret = ret;       /* explicit shadow */                   \
213                                                                         \
214         INIT_LIST_HEAD(&__wait.task_list);                              \
215         if (exclusive)                                                  \
216                 __wait.flags = WQ_FLAG_EXCLUSIVE;                       \
217         else                                                            \
218                 __wait.flags = 0;                                       \
219                                                                         \
220         for (;;) {                                                      \
221                 long __int = prepare_to_wait_event(&wq, &__wait, state);\
222                                                                         \
223                 if (condition)                                          \
224                         break;                                          \
225                                                                         \
226                 if (___wait_is_interruptible(state) && __int) {         \
227                         __ret = __int;                                  \
228                         if (exclusive) {                                \
229                                 abort_exclusive_wait(&wq, &__wait,      \
230                                                      state, NULL);      \
231                                 goto __out;                             \
232                         }                                               \
233                         break;                                          \
234                 }                                                       \
235                                                                         \
236                 cmd;                                                    \
237         }                                                               \
238         finish_wait(&wq, &__wait);                                      \
239 __out:  __ret;                                                          \
240 })
241 
242 #define __wait_event(wq, condition)                                     \
243         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
244                             schedule())
245 
246 /**
247  * wait_event - sleep until a condition gets true
248  * @wq: the waitqueue to wait on
249  * @condition: a C expression for the event to wait for
250  *
251  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
252  * @condition evaluates to true. The @condition is checked each time
253  * the waitqueue @wq is woken up.
254  *
255  * wake_up() has to be called after changing any variable that could
256  * change the result of the wait condition.
257  */
258 #define wait_event(wq, condition)                                       \
259 do {                                                                    \
260         if (condition)                                                  \
261                 break;                                                  \
262         __wait_event(wq, condition);                                    \
263 } while (0)
264 
265 #define __wait_event_timeout(wq, condition, timeout)                    \
266         ___wait_event(wq, ___wait_cond_timeout(condition),              \
267                       TASK_UNINTERRUPTIBLE, 0, timeout,                 \
268                       __ret = schedule_timeout(__ret))
269 
270 /**
271  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
272  * @wq: the waitqueue to wait on
273  * @condition: a C expression for the event to wait for
274  * @timeout: timeout, in jiffies
275  *
276  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
277  * @condition evaluates to true. The @condition is checked each time
278  * the waitqueue @wq is woken up.
279  *
280  * wake_up() has to be called after changing any variable that could
281  * change the result of the wait condition.
282  *
283  * The function returns 0 if the @timeout elapsed, or the remaining
284  * jiffies (at least 1) if the @condition evaluated to %true before
285  * the @timeout elapsed.
286  */
287 #define wait_event_timeout(wq, condition, timeout)                      \
288 ({                                                                      \
289         long __ret = timeout;                                           \
290         if (!___wait_cond_timeout(condition))                           \
291                 __ret = __wait_event_timeout(wq, condition, timeout);   \
292         __ret;                                                          \
293 })
294 
295 #define __wait_event_cmd(wq, condition, cmd1, cmd2)                     \
296         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
297                             cmd1; schedule(); cmd2)
298 
299 /**
300  * wait_event_cmd - sleep until a condition gets true
301  * @wq: the waitqueue to wait on
302  * @condition: a C expression for the event to wait for
303  * @cmd1: the command will be executed before sleep
304  * @cmd2: the command will be executed after sleep
305  *
306  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
307  * @condition evaluates to true. The @condition is checked each time
308  * the waitqueue @wq is woken up.
309  *
310  * wake_up() has to be called after changing any variable that could
311  * change the result of the wait condition.
312  */
313 #define wait_event_cmd(wq, condition, cmd1, cmd2)                       \
314 do {                                                                    \
315         if (condition)                                                  \
316                 break;                                                  \
317         __wait_event_cmd(wq, condition, cmd1, cmd2);                    \
318 } while (0)
319 
320 #define __wait_event_interruptible(wq, condition)                       \
321         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
322                       schedule())
323 
324 /**
325  * wait_event_interruptible - sleep until a condition gets true
326  * @wq: the waitqueue to wait on
327  * @condition: a C expression for the event to wait for
328  *
329  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
330  * @condition evaluates to true or a signal is received.
331  * The @condition is checked each time the waitqueue @wq is woken up.
332  *
333  * wake_up() has to be called after changing any variable that could
334  * change the result of the wait condition.
335  *
336  * The function will return -ERESTARTSYS if it was interrupted by a
337  * signal and 0 if @condition evaluated to true.
338  */
339 #define wait_event_interruptible(wq, condition)                         \
340 ({                                                                      \
341         int __ret = 0;                                                  \
342         if (!(condition))                                               \
343                 __ret = __wait_event_interruptible(wq, condition);      \
344         __ret;                                                          \
345 })
346 
347 #define __wait_event_interruptible_timeout(wq, condition, timeout)      \
348         ___wait_event(wq, ___wait_cond_timeout(condition),              \
349                       TASK_INTERRUPTIBLE, 0, timeout,                   \
350                       __ret = schedule_timeout(__ret))
351 
352 /**
353  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
354  * @wq: the waitqueue to wait on
355  * @condition: a C expression for the event to wait for
356  * @timeout: timeout, in jiffies
357  *
358  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
359  * @condition evaluates to true or a signal is received.
360  * The @condition is checked each time the waitqueue @wq is woken up.
361  *
362  * wake_up() has to be called after changing any variable that could
363  * change the result of the wait condition.
364  *
365  * Returns:
366  * 0 if the @timeout elapsed, -%ERESTARTSYS if it was interrupted by
367  * a signal, or the remaining jiffies (at least 1) if the @condition
368  * evaluated to %true before the @timeout elapsed.
369  */
370 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
371 ({                                                                      \
372         long __ret = timeout;                                           \
373         if (!___wait_cond_timeout(condition))                           \
374                 __ret = __wait_event_interruptible_timeout(wq,          \
375                                                 condition, timeout);    \
376         __ret;                                                          \
377 })
378 
379 #define __wait_event_hrtimeout(wq, condition, timeout, state)           \
380 ({                                                                      \
381         int __ret = 0;                                                  \
382         struct hrtimer_sleeper __t;                                     \
383                                                                         \
384         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
385                               HRTIMER_MODE_REL);                        \
386         hrtimer_init_sleeper(&__t, current);                            \
387         if ((timeout).tv64 != KTIME_MAX)                                \
388                 hrtimer_start_range_ns(&__t.timer, timeout,             \
389                                        current->timer_slack_ns,         \
390                                        HRTIMER_MODE_REL);               \
391                                                                         \
392         __ret = ___wait_event(wq, condition, state, 0, 0,               \
393                 if (!__t.task) {                                        \
394                         __ret = -ETIME;                                 \
395                         break;                                          \
396                 }                                                       \
397                 schedule());                                            \
398                                                                         \
399         hrtimer_cancel(&__t.timer);                                     \
400         destroy_hrtimer_on_stack(&__t.timer);                           \
401         __ret;                                                          \
402 })
403 
404 /**
405  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
406  * @wq: the waitqueue to wait on
407  * @condition: a C expression for the event to wait for
408  * @timeout: timeout, as a ktime_t
409  *
410  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
411  * @condition evaluates to true or a signal is received.
412  * The @condition is checked each time the waitqueue @wq is woken up.
413  *
414  * wake_up() has to be called after changing any variable that could
415  * change the result of the wait condition.
416  *
417  * The function returns 0 if @condition became true, or -ETIME if the timeout
418  * elapsed.
419  */
420 #define wait_event_hrtimeout(wq, condition, timeout)                    \
421 ({                                                                      \
422         int __ret = 0;                                                  \
423         if (!(condition))                                               \
424                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
425                                                TASK_UNINTERRUPTIBLE);   \
426         __ret;                                                          \
427 })
428 
429 /**
430  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
431  * @wq: the waitqueue to wait on
432  * @condition: a C expression for the event to wait for
433  * @timeout: timeout, as a ktime_t
434  *
435  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
436  * @condition evaluates to true or a signal is received.
437  * The @condition is checked each time the waitqueue @wq is woken up.
438  *
439  * wake_up() has to be called after changing any variable that could
440  * change the result of the wait condition.
441  *
442  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
443  * interrupted by a signal, or -ETIME if the timeout elapsed.
444  */
445 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
446 ({                                                                      \
447         long __ret = 0;                                                 \
448         if (!(condition))                                               \
449                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
450                                                TASK_INTERRUPTIBLE);     \
451         __ret;                                                          \
452 })
453 
454 #define __wait_event_interruptible_exclusive(wq, condition)             \
455         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
456                       schedule())
457 
458 #define wait_event_interruptible_exclusive(wq, condition)               \
459 ({                                                                      \
460         int __ret = 0;                                                  \
461         if (!(condition))                                               \
462                 __ret = __wait_event_interruptible_exclusive(wq, condition);\
463         __ret;                                                          \
464 })
465 
466 
467 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
468 ({                                                                      \
469         int __ret = 0;                                                  \
470         DEFINE_WAIT(__wait);                                            \
471         if (exclusive)                                                  \
472                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
473         do {                                                            \
474                 if (likely(list_empty(&__wait.task_list)))              \
475                         __add_wait_queue_tail(&(wq), &__wait);          \
476                 set_current_state(TASK_INTERRUPTIBLE);                  \
477                 if (signal_pending(current)) {                          \
478                         __ret = -ERESTARTSYS;                           \
479                         break;                                          \
480                 }                                                       \
481                 if (irq)                                                \
482                         spin_unlock_irq(&(wq).lock);                    \
483                 else                                                    \
484                         spin_unlock(&(wq).lock);                        \
485                 schedule();                                             \
486                 if (irq)                                                \
487                         spin_lock_irq(&(wq).lock);                      \
488                 else                                                    \
489                         spin_lock(&(wq).lock);                          \
490         } while (!(condition));                                         \
491         __remove_wait_queue(&(wq), &__wait);                            \
492         __set_current_state(TASK_RUNNING);                              \
493         __ret;                                                          \
494 })
495 
496 
497 /**
498  * wait_event_interruptible_locked - sleep until a condition gets true
499  * @wq: the waitqueue to wait on
500  * @condition: a C expression for the event to wait for
501  *
502  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
503  * @condition evaluates to true or a signal is received.
504  * The @condition is checked each time the waitqueue @wq is woken up.
505  *
506  * It must be called with wq.lock being held.  This spinlock is
507  * unlocked while sleeping but @condition testing is done while lock
508  * is held and when this macro exits the lock is held.
509  *
510  * The lock is locked/unlocked using spin_lock()/spin_unlock()
511  * functions which must match the way they are locked/unlocked outside
512  * of this macro.
513  *
514  * wake_up_locked() has to be called after changing any variable that could
515  * change the result of the wait condition.
516  *
517  * The function will return -ERESTARTSYS if it was interrupted by a
518  * signal and 0 if @condition evaluated to true.
519  */
520 #define wait_event_interruptible_locked(wq, condition)                  \
521         ((condition)                                                    \
522          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
523 
524 /**
525  * wait_event_interruptible_locked_irq - sleep until a condition gets true
526  * @wq: the waitqueue to wait on
527  * @condition: a C expression for the event to wait for
528  *
529  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
530  * @condition evaluates to true or a signal is received.
531  * The @condition is checked each time the waitqueue @wq is woken up.
532  *
533  * It must be called with wq.lock being held.  This spinlock is
534  * unlocked while sleeping but @condition testing is done while lock
535  * is held and when this macro exits the lock is held.
536  *
537  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
538  * functions which must match the way they are locked/unlocked outside
539  * of this macro.
540  *
541  * wake_up_locked() has to be called after changing any variable that could
542  * change the result of the wait condition.
543  *
544  * The function will return -ERESTARTSYS if it was interrupted by a
545  * signal and 0 if @condition evaluated to true.
546  */
547 #define wait_event_interruptible_locked_irq(wq, condition)              \
548         ((condition)                                                    \
549          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
550 
551 /**
552  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
553  * @wq: the waitqueue to wait on
554  * @condition: a C expression for the event to wait for
555  *
556  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
557  * @condition evaluates to true or a signal is received.
558  * The @condition is checked each time the waitqueue @wq is woken up.
559  *
560  * It must be called with wq.lock being held.  This spinlock is
561  * unlocked while sleeping but @condition testing is done while lock
562  * is held and when this macro exits the lock is held.
563  *
564  * The lock is locked/unlocked using spin_lock()/spin_unlock()
565  * functions which must match the way they are locked/unlocked outside
566  * of this macro.
567  *
568  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
569  * set thus when other process waits process on the list if this
570  * process is awaken further processes are not considered.
571  *
572  * wake_up_locked() has to be called after changing any variable that could
573  * change the result of the wait condition.
574  *
575  * The function will return -ERESTARTSYS if it was interrupted by a
576  * signal and 0 if @condition evaluated to true.
577  */
578 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
579         ((condition)                                                    \
580          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
581 
582 /**
583  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
584  * @wq: the waitqueue to wait on
585  * @condition: a C expression for the event to wait for
586  *
587  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
588  * @condition evaluates to true or a signal is received.
589  * The @condition is checked each time the waitqueue @wq is woken up.
590  *
591  * It must be called with wq.lock being held.  This spinlock is
592  * unlocked while sleeping but @condition testing is done while lock
593  * is held and when this macro exits the lock is held.
594  *
595  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
596  * functions which must match the way they are locked/unlocked outside
597  * of this macro.
598  *
599  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
600  * set thus when other process waits process on the list if this
601  * process is awaken further processes are not considered.
602  *
603  * wake_up_locked() has to be called after changing any variable that could
604  * change the result of the wait condition.
605  *
606  * The function will return -ERESTARTSYS if it was interrupted by a
607  * signal and 0 if @condition evaluated to true.
608  */
609 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
610         ((condition)                                                    \
611          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
612 
613 
614 #define __wait_event_killable(wq, condition)                            \
615         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
616 
617 /**
618  * wait_event_killable - sleep until a condition gets true
619  * @wq: the waitqueue to wait on
620  * @condition: a C expression for the event to wait for
621  *
622  * The process is put to sleep (TASK_KILLABLE) until the
623  * @condition evaluates to true or a signal is received.
624  * The @condition is checked each time the waitqueue @wq is woken up.
625  *
626  * wake_up() has to be called after changing any variable that could
627  * change the result of the wait condition.
628  *
629  * The function will return -ERESTARTSYS if it was interrupted by a
630  * signal and 0 if @condition evaluated to true.
631  */
632 #define wait_event_killable(wq, condition)                              \
633 ({                                                                      \
634         int __ret = 0;                                                  \
635         if (!(condition))                                               \
636                 __ret = __wait_event_killable(wq, condition);           \
637         __ret;                                                          \
638 })
639 
640 
641 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
642         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
643                             spin_unlock_irq(&lock);                     \
644                             cmd;                                        \
645                             schedule();                                 \
646                             spin_lock_irq(&lock))
647 
648 /**
649  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
650  *                           condition is checked under the lock. This
651  *                           is expected to be called with the lock
652  *                           taken.
653  * @wq: the waitqueue to wait on
654  * @condition: a C expression for the event to wait for
655  * @lock: a locked spinlock_t, which will be released before cmd
656  *        and schedule() and reacquired afterwards.
657  * @cmd: a command which is invoked outside the critical section before
658  *       sleep
659  *
660  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
661  * @condition evaluates to true. The @condition is checked each time
662  * the waitqueue @wq is woken up.
663  *
664  * wake_up() has to be called after changing any variable that could
665  * change the result of the wait condition.
666  *
667  * This is supposed to be called while holding the lock. The lock is
668  * dropped before invoking the cmd and going to sleep and is reacquired
669  * afterwards.
670  */
671 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
672 do {                                                                    \
673         if (condition)                                                  \
674                 break;                                                  \
675         __wait_event_lock_irq(wq, condition, lock, cmd);                \
676 } while (0)
677 
678 /**
679  * wait_event_lock_irq - sleep until a condition gets true. The
680  *                       condition is checked under the lock. This
681  *                       is expected to be called with the lock
682  *                       taken.
683  * @wq: the waitqueue to wait on
684  * @condition: a C expression for the event to wait for
685  * @lock: a locked spinlock_t, which will be released before schedule()
686  *        and reacquired afterwards.
687  *
688  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
689  * @condition evaluates to true. The @condition is checked each time
690  * the waitqueue @wq is woken up.
691  *
692  * wake_up() has to be called after changing any variable that could
693  * change the result of the wait condition.
694  *
695  * This is supposed to be called while holding the lock. The lock is
696  * dropped before going to sleep and is reacquired afterwards.
697  */
698 #define wait_event_lock_irq(wq, condition, lock)                        \
699 do {                                                                    \
700         if (condition)                                                  \
701                 break;                                                  \
702         __wait_event_lock_irq(wq, condition, lock, );                   \
703 } while (0)
704 
705 
706 #define __wait_event_interruptible_lock_irq(wq, condition, lock, cmd)   \
707         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
708                       spin_unlock_irq(&lock);                           \
709                       cmd;                                              \
710                       schedule();                                       \
711                       spin_lock_irq(&lock))
712 
713 /**
714  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
715  *              The condition is checked under the lock. This is expected to
716  *              be called with the lock taken.
717  * @wq: the waitqueue to wait on
718  * @condition: a C expression for the event to wait for
719  * @lock: a locked spinlock_t, which will be released before cmd and
720  *        schedule() and reacquired afterwards.
721  * @cmd: a command which is invoked outside the critical section before
722  *       sleep
723  *
724  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
725  * @condition evaluates to true or a signal is received. The @condition is
726  * checked each time the waitqueue @wq is woken up.
727  *
728  * wake_up() has to be called after changing any variable that could
729  * change the result of the wait condition.
730  *
731  * This is supposed to be called while holding the lock. The lock is
732  * dropped before invoking the cmd and going to sleep and is reacquired
733  * afterwards.
734  *
735  * The macro will return -ERESTARTSYS if it was interrupted by a signal
736  * and 0 if @condition evaluated to true.
737  */
738 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
739 ({                                                                      \
740         int __ret = 0;                                                  \
741         if (!(condition))                                               \
742                 __ret = __wait_event_interruptible_lock_irq(wq,         \
743                                                 condition, lock, cmd);  \
744         __ret;                                                          \
745 })
746 
747 /**
748  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
749  *              The condition is checked under the lock. This is expected
750  *              to be called with the lock taken.
751  * @wq: the waitqueue to wait on
752  * @condition: a C expression for the event to wait for
753  * @lock: a locked spinlock_t, which will be released before schedule()
754  *        and reacquired afterwards.
755  *
756  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
757  * @condition evaluates to true or signal is received. The @condition is
758  * checked each time the waitqueue @wq is woken up.
759  *
760  * wake_up() has to be called after changing any variable that could
761  * change the result of the wait condition.
762  *
763  * This is supposed to be called while holding the lock. The lock is
764  * dropped before going to sleep and is reacquired afterwards.
765  *
766  * The macro will return -ERESTARTSYS if it was interrupted by a signal
767  * and 0 if @condition evaluated to true.
768  */
769 #define wait_event_interruptible_lock_irq(wq, condition, lock)          \
770 ({                                                                      \
771         int __ret = 0;                                                  \
772         if (!(condition))                                               \
773                 __ret = __wait_event_interruptible_lock_irq(wq,         \
774                                                 condition, lock,);      \
775         __ret;                                                          \
776 })
777 
778 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
779                                                     lock, timeout)      \
780         ___wait_event(wq, ___wait_cond_timeout(condition),              \
781                       TASK_INTERRUPTIBLE, 0, timeout,                   \
782                       spin_unlock_irq(&lock);                           \
783                       __ret = schedule_timeout(__ret);                  \
784                       spin_lock_irq(&lock));
785 
786 /**
787  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
788  *              true or a timeout elapses. The condition is checked under
789  *              the lock. This is expected to be called with the lock taken.
790  * @wq: the waitqueue to wait on
791  * @condition: a C expression for the event to wait for
792  * @lock: a locked spinlock_t, which will be released before schedule()
793  *        and reacquired afterwards.
794  * @timeout: timeout, in jiffies
795  *
796  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
797  * @condition evaluates to true or signal is received. The @condition is
798  * checked each time the waitqueue @wq is woken up.
799  *
800  * wake_up() has to be called after changing any variable that could
801  * change the result of the wait condition.
802  *
803  * This is supposed to be called while holding the lock. The lock is
804  * dropped before going to sleep and is reacquired afterwards.
805  *
806  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
807  * was interrupted by a signal, and the remaining jiffies otherwise
808  * if the condition evaluated to true before the timeout elapsed.
809  */
810 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
811                                                   timeout)              \
812 ({                                                                      \
813         long __ret = timeout;                                           \
814         if (!___wait_cond_timeout(condition))                           \
815                 __ret = __wait_event_interruptible_lock_irq_timeout(    \
816                                         wq, condition, lock, timeout);  \
817         __ret;                                                          \
818 })
819 
820 /*
821  * Waitqueues which are removed from the waitqueue_head at wakeup time
822  */
823 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
824 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
825 long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state);
826 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
827 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key);
828 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
829 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
830 
831 #define DEFINE_WAIT_FUNC(name, function)                                \
832         wait_queue_t name = {                                           \
833                 .private        = current,                              \
834                 .func           = function,                             \
835                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
836         }
837 
838 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
839 
840 #define DEFINE_WAIT_BIT(name, word, bit)                                \
841         struct wait_bit_queue name = {                                  \
842                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
843                 .wait   = {                                             \
844                         .private        = current,                      \
845                         .func           = wake_bit_function,            \
846                         .task_list      =                               \
847                                 LIST_HEAD_INIT((name).wait.task_list),  \
848                 },                                                      \
849         }
850 
851 #define init_wait(wait)                                                 \
852         do {                                                            \
853                 (wait)->private = current;                              \
854                 (wait)->func = autoremove_wake_function;                \
855                 INIT_LIST_HEAD(&(wait)->task_list);                     \
856                 (wait)->flags = 0;                                      \
857         } while (0)
858 
859 
860 extern int bit_wait(struct wait_bit_key *);
861 extern int bit_wait_io(struct wait_bit_key *);
862 
863 /**
864  * wait_on_bit - wait for a bit to be cleared
865  * @word: the word being waited on, a kernel virtual address
866  * @bit: the bit of the word being waited on
867  * @mode: the task state to sleep in
868  *
869  * There is a standard hashed waitqueue table for generic use. This
870  * is the part of the hashtable's accessor API that waits on a bit.
871  * For instance, if one were to have waiters on a bitflag, one would
872  * call wait_on_bit() in threads waiting for the bit to clear.
873  * One uses wait_on_bit() where one is waiting for the bit to clear,
874  * but has no intention of setting it.
875  * Returned value will be zero if the bit was cleared, or non-zero
876  * if the process received a signal and the mode permitted wakeup
877  * on that signal.
878  */
879 static inline int
880 wait_on_bit(void *word, int bit, unsigned mode)
881 {
882         if (!test_bit(bit, word))
883                 return 0;
884         return out_of_line_wait_on_bit(word, bit,
885                                        bit_wait,
886                                        mode);
887 }
888 
889 /**
890  * wait_on_bit_io - wait for a bit to be cleared
891  * @word: the word being waited on, a kernel virtual address
892  * @bit: the bit of the word being waited on
893  * @mode: the task state to sleep in
894  *
895  * Use the standard hashed waitqueue table to wait for a bit
896  * to be cleared.  This is similar to wait_on_bit(), but calls
897  * io_schedule() instead of schedule() for the actual waiting.
898  *
899  * Returned value will be zero if the bit was cleared, or non-zero
900  * if the process received a signal and the mode permitted wakeup
901  * on that signal.
902  */
903 static inline int
904 wait_on_bit_io(void *word, int bit, unsigned mode)
905 {
906         if (!test_bit(bit, word))
907                 return 0;
908         return out_of_line_wait_on_bit(word, bit,
909                                        bit_wait_io,
910                                        mode);
911 }
912 
913 /**
914  * wait_on_bit_action - wait for a bit to be cleared
915  * @word: the word being waited on, a kernel virtual address
916  * @bit: the bit of the word being waited on
917  * @action: the function used to sleep, which may take special actions
918  * @mode: the task state to sleep in
919  *
920  * Use the standard hashed waitqueue table to wait for a bit
921  * to be cleared, and allow the waiting action to be specified.
922  * This is like wait_on_bit() but allows fine control of how the waiting
923  * is done.
924  *
925  * Returned value will be zero if the bit was cleared, or non-zero
926  * if the process received a signal and the mode permitted wakeup
927  * on that signal.
928  */
929 static inline int
930 wait_on_bit_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
931 {
932         if (!test_bit(bit, word))
933                 return 0;
934         return out_of_line_wait_on_bit(word, bit, action, mode);
935 }
936 
937 /**
938  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
939  * @word: the word being waited on, a kernel virtual address
940  * @bit: the bit of the word being waited on
941  * @mode: the task state to sleep in
942  *
943  * There is a standard hashed waitqueue table for generic use. This
944  * is the part of the hashtable's accessor API that waits on a bit
945  * when one intends to set it, for instance, trying to lock bitflags.
946  * For instance, if one were to have waiters trying to set bitflag
947  * and waiting for it to clear before setting it, one would call
948  * wait_on_bit() in threads waiting to be able to set the bit.
949  * One uses wait_on_bit_lock() where one is waiting for the bit to
950  * clear with the intention of setting it, and when done, clearing it.
951  *
952  * Returns zero if the bit was (eventually) found to be clear and was
953  * set.  Returns non-zero if a signal was delivered to the process and
954  * the @mode allows that signal to wake the process.
955  */
956 static inline int
957 wait_on_bit_lock(void *word, int bit, unsigned mode)
958 {
959         if (!test_and_set_bit(bit, word))
960                 return 0;
961         return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode);
962 }
963 
964 /**
965  * wait_on_bit_lock_io - wait for a bit to be cleared, when wanting to set it
966  * @word: the word being waited on, a kernel virtual address
967  * @bit: the bit of the word being waited on
968  * @mode: the task state to sleep in
969  *
970  * Use the standard hashed waitqueue table to wait for a bit
971  * to be cleared and then to atomically set it.  This is similar
972  * to wait_on_bit(), but calls io_schedule() instead of schedule()
973  * for the actual waiting.
974  *
975  * Returns zero if the bit was (eventually) found to be clear and was
976  * set.  Returns non-zero if a signal was delivered to the process and
977  * the @mode allows that signal to wake the process.
978  */
979 static inline int
980 wait_on_bit_lock_io(void *word, int bit, unsigned mode)
981 {
982         if (!test_and_set_bit(bit, word))
983                 return 0;
984         return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode);
985 }
986 
987 /**
988  * wait_on_bit_lock_action - wait for a bit to be cleared, when wanting to set it
989  * @word: the word being waited on, a kernel virtual address
990  * @bit: the bit of the word being waited on
991  * @action: the function used to sleep, which may take special actions
992  * @mode: the task state to sleep in
993  *
994  * Use the standard hashed waitqueue table to wait for a bit
995  * to be cleared and then to set it, and allow the waiting action
996  * to be specified.
997  * This is like wait_on_bit() but allows fine control of how the waiting
998  * is done.
999  *
1000  * Returns zero if the bit was (eventually) found to be clear and was
1001  * set.  Returns non-zero if a signal was delivered to the process and
1002  * the @mode allows that signal to wake the process.
1003  */
1004 static inline int
1005 wait_on_bit_lock_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
1006 {
1007         if (!test_and_set_bit(bit, word))
1008                 return 0;
1009         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
1010 }
1011 
1012 /**
1013  * wait_on_atomic_t - Wait for an atomic_t to become 0
1014  * @val: The atomic value being waited on, a kernel virtual address
1015  * @action: the function used to sleep, which may take special actions
1016  * @mode: the task state to sleep in
1017  *
1018  * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
1019  * the purpose of getting a waitqueue, but we set the key to a bit number
1020  * outside of the target 'word'.
1021  */
1022 static inline
1023 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
1024 {
1025         if (atomic_read(val) == 0)
1026                 return 0;
1027         return out_of_line_wait_on_atomic_t(val, action, mode);
1028 }
1029 
1030 #endif /* _LINUX_WAIT_H */
1031 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us