Version:  2.6.34 2.6.35 2.6.36 2.6.37 2.6.38 2.6.39 3.0 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

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

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