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

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  1 #ifndef _LINUX_WAIT_H
  2 #define _LINUX_WAIT_H
  3 
  4 
  5 #include <linux/list.h>
  6 #include <linux/stddef.h>
  7 #include <linux/spinlock.h>
  8 #include <asm/current.h>
  9 #include <uapi/linux/wait.h>
 10 
 11 typedef struct __wait_queue wait_queue_t;
 12 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key);
 13 int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, void *key);
 14 
 15 struct __wait_queue {
 16         unsigned int flags;
 17 #define WQ_FLAG_EXCLUSIVE       0x01
 18         void *private;
 19         wait_queue_func_t func;
 20         struct list_head task_list;
 21 };
 22 
 23 struct wait_bit_key {
 24         void *flags;
 25         int bit_nr;
 26 };
 27 
 28 struct wait_bit_queue {
 29         struct wait_bit_key key;
 30         wait_queue_t wait;
 31 };
 32 
 33 struct __wait_queue_head {
 34         spinlock_t lock;
 35         struct list_head task_list;
 36 };
 37 typedef struct __wait_queue_head wait_queue_head_t;
 38 
 39 struct task_struct;
 40 
 41 /*
 42  * Macros for declaration and initialisaton of the datatypes
 43  */
 44 
 45 #define __WAITQUEUE_INITIALIZER(name, tsk) {                            \
 46         .private        = tsk,                                          \
 47         .func           = default_wake_function,                        \
 48         .task_list      = { NULL, NULL } }
 49 
 50 #define DECLARE_WAITQUEUE(name, tsk)                                    \
 51         wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
 52 
 53 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                           \
 54         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),              \
 55         .task_list      = { &(name).task_list, &(name).task_list } }
 56 
 57 #define DECLARE_WAIT_QUEUE_HEAD(name) \
 58         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
 59 
 60 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)                           \
 61         { .flags = word, .bit_nr = bit, }
 62 
 63 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
 64 
 65 #define init_waitqueue_head(q)                          \
 66         do {                                            \
 67                 static struct lock_class_key __key;     \
 68                                                         \
 69                 __init_waitqueue_head((q), #q, &__key); \
 70         } while (0)
 71 
 72 #ifdef CONFIG_LOCKDEP
 73 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
 74         ({ init_waitqueue_head(&name); name; })
 75 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
 76         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
 77 #else
 78 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
 79 #endif
 80 
 81 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
 82 {
 83         q->flags = 0;
 84         q->private = p;
 85         q->func = default_wake_function;
 86 }
 87 
 88 static inline void init_waitqueue_func_entry(wait_queue_t *q,
 89                                         wait_queue_func_t func)
 90 {
 91         q->flags = 0;
 92         q->private = NULL;
 93         q->func = func;
 94 }
 95 
 96 static inline int waitqueue_active(wait_queue_head_t *q)
 97 {
 98         return !list_empty(&q->task_list);
 99 }
100 
101 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
102 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
103 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
104 
105 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
106 {
107         list_add(&new->task_list, &head->task_list);
108 }
109 
110 /*
111  * Used for wake-one threads:
112  */
113 static inline void __add_wait_queue_exclusive(wait_queue_head_t *q,
114                                               wait_queue_t *wait)
115 {
116         wait->flags |= WQ_FLAG_EXCLUSIVE;
117         __add_wait_queue(q, wait);
118 }
119 
120 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
121                                          wait_queue_t *new)
122 {
123         list_add_tail(&new->task_list, &head->task_list);
124 }
125 
126 static inline void __add_wait_queue_tail_exclusive(wait_queue_head_t *q,
127                                               wait_queue_t *wait)
128 {
129         wait->flags |= WQ_FLAG_EXCLUSIVE;
130         __add_wait_queue_tail(q, wait);
131 }
132 
133 static inline void __remove_wait_queue(wait_queue_head_t *head,
134                                                         wait_queue_t *old)
135 {
136         list_del(&old->task_list);
137 }
138 
139 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
140 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
141 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr,
142                         void *key);
143 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
144 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
145 void __wake_up_bit(wait_queue_head_t *, void *, int);
146 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
147 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
148 void wake_up_bit(void *, int);
149 int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned);
150 int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned);
151 wait_queue_head_t *bit_waitqueue(void *, int);
152 
153 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
154 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
155 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
156 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL, 1)
157 #define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)
158 
159 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
160 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
161 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
162 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
163 
164 /*
165  * Wakeup macros to be used to report events to the targets.
166  */
167 #define wake_up_poll(x, m)                              \
168         __wake_up(x, TASK_NORMAL, 1, (void *) (m))
169 #define wake_up_locked_poll(x, m)                               \
170         __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
171 #define wake_up_interruptible_poll(x, m)                        \
172         __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
173 #define wake_up_interruptible_sync_poll(x, m)                           \
174         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
175 
176 #define __wait_event(wq, condition)                                     \
177 do {                                                                    \
178         DEFINE_WAIT(__wait);                                            \
179                                                                         \
180         for (;;) {                                                      \
181                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
182                 if (condition)                                          \
183                         break;                                          \
184                 schedule();                                             \
185         }                                                               \
186         finish_wait(&wq, &__wait);                                      \
187 } while (0)
188 
189 /**
190  * wait_event - sleep until a condition gets true
191  * @wq: the waitqueue to wait on
192  * @condition: a C expression for the event to wait for
193  *
194  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
195  * @condition evaluates to true. The @condition is checked each time
196  * the waitqueue @wq is woken up.
197  *
198  * wake_up() has to be called after changing any variable that could
199  * change the result of the wait condition.
200  */
201 #define wait_event(wq, condition)                                       \
202 do {                                                                    \
203         if (condition)                                                  \
204                 break;                                                  \
205         __wait_event(wq, condition);                                    \
206 } while (0)
207 
208 #define __wait_event_timeout(wq, condition, ret)                        \
209 do {                                                                    \
210         DEFINE_WAIT(__wait);                                            \
211                                                                         \
212         for (;;) {                                                      \
213                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
214                 if (condition)                                          \
215                         break;                                          \
216                 ret = schedule_timeout(ret);                            \
217                 if (!ret)                                               \
218                         break;                                          \
219         }                                                               \
220         if (!ret && (condition))                                        \
221                 ret = 1;                                                \
222         finish_wait(&wq, &__wait);                                      \
223 } while (0)
224 
225 /**
226  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
227  * @wq: the waitqueue to wait on
228  * @condition: a C expression for the event to wait for
229  * @timeout: timeout, in jiffies
230  *
231  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
232  * @condition evaluates to true. The @condition is checked each time
233  * the waitqueue @wq is woken up.
234  *
235  * wake_up() has to be called after changing any variable that could
236  * change the result of the wait condition.
237  *
238  * The function returns 0 if the @timeout elapsed, or the remaining
239  * jiffies (at least 1) if the @condition evaluated to %true before
240  * the @timeout elapsed.
241  */
242 #define wait_event_timeout(wq, condition, timeout)                      \
243 ({                                                                      \
244         long __ret = timeout;                                           \
245         if (!(condition))                                               \
246                 __wait_event_timeout(wq, condition, __ret);             \
247         __ret;                                                          \
248 })
249 
250 #define __wait_event_interruptible(wq, condition, ret)                  \
251 do {                                                                    \
252         DEFINE_WAIT(__wait);                                            \
253                                                                         \
254         for (;;) {                                                      \
255                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
256                 if (condition)                                          \
257                         break;                                          \
258                 if (!signal_pending(current)) {                         \
259                         schedule();                                     \
260                         continue;                                       \
261                 }                                                       \
262                 ret = -ERESTARTSYS;                                     \
263                 break;                                                  \
264         }                                                               \
265         finish_wait(&wq, &__wait);                                      \
266 } while (0)
267 
268 /**
269  * wait_event_interruptible - sleep until a condition gets true
270  * @wq: the waitqueue to wait on
271  * @condition: a C expression for the event to wait for
272  *
273  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
274  * @condition evaluates to true or a signal is received.
275  * The @condition is checked each time the waitqueue @wq is woken up.
276  *
277  * wake_up() has to be called after changing any variable that could
278  * change the result of the wait condition.
279  *
280  * The function will return -ERESTARTSYS if it was interrupted by a
281  * signal and 0 if @condition evaluated to true.
282  */
283 #define wait_event_interruptible(wq, condition)                         \
284 ({                                                                      \
285         int __ret = 0;                                                  \
286         if (!(condition))                                               \
287                 __wait_event_interruptible(wq, condition, __ret);       \
288         __ret;                                                          \
289 })
290 
291 #define __wait_event_interruptible_timeout(wq, condition, ret)          \
292 do {                                                                    \
293         DEFINE_WAIT(__wait);                                            \
294                                                                         \
295         for (;;) {                                                      \
296                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
297                 if (condition)                                          \
298                         break;                                          \
299                 if (!signal_pending(current)) {                         \
300                         ret = schedule_timeout(ret);                    \
301                         if (!ret)                                       \
302                                 break;                                  \
303                         continue;                                       \
304                 }                                                       \
305                 ret = -ERESTARTSYS;                                     \
306                 break;                                                  \
307         }                                                               \
308         if (!ret && (condition))                                        \
309                 ret = 1;                                                \
310         finish_wait(&wq, &__wait);                                      \
311 } while (0)
312 
313 /**
314  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
315  * @wq: the waitqueue to wait on
316  * @condition: a C expression for the event to wait for
317  * @timeout: timeout, in jiffies
318  *
319  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
320  * @condition evaluates to true or a signal is received.
321  * The @condition is checked each time the waitqueue @wq is woken up.
322  *
323  * wake_up() has to be called after changing any variable that could
324  * change the result of the wait condition.
325  *
326  * Returns:
327  * 0 if the @timeout elapsed, -%ERESTARTSYS if it was interrupted by
328  * a signal, or the remaining jiffies (at least 1) if the @condition
329  * evaluated to %true before the @timeout elapsed.
330  */
331 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
332 ({                                                                      \
333         long __ret = timeout;                                           \
334         if (!(condition))                                               \
335                 __wait_event_interruptible_timeout(wq, condition, __ret); \
336         __ret;                                                          \
337 })
338 
339 #define __wait_event_hrtimeout(wq, condition, timeout, state)           \
340 ({                                                                      \
341         int __ret = 0;                                                  \
342         DEFINE_WAIT(__wait);                                            \
343         struct hrtimer_sleeper __t;                                     \
344                                                                         \
345         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
346                               HRTIMER_MODE_REL);                        \
347         hrtimer_init_sleeper(&__t, current);                            \
348         if ((timeout).tv64 != KTIME_MAX)                                \
349                 hrtimer_start_range_ns(&__t.timer, timeout,             \
350                                        current->timer_slack_ns,         \
351                                        HRTIMER_MODE_REL);               \
352                                                                         \
353         for (;;) {                                                      \
354                 prepare_to_wait(&wq, &__wait, state);                   \
355                 if (condition)                                          \
356                         break;                                          \
357                 if (state == TASK_INTERRUPTIBLE &&                      \
358                     signal_pending(current)) {                          \
359                         __ret = -ERESTARTSYS;                           \
360                         break;                                          \
361                 }                                                       \
362                 if (!__t.task) {                                        \
363                         __ret = -ETIME;                                 \
364                         break;                                          \
365                 }                                                       \
366                 schedule();                                             \
367         }                                                               \
368                                                                         \
369         hrtimer_cancel(&__t.timer);                                     \
370         destroy_hrtimer_on_stack(&__t.timer);                           \
371         finish_wait(&wq, &__wait);                                      \
372         __ret;                                                          \
373 })
374 
375 /**
376  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
377  * @wq: the waitqueue to wait on
378  * @condition: a C expression for the event to wait for
379  * @timeout: timeout, as a ktime_t
380  *
381  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
382  * @condition evaluates to true or a signal is received.
383  * The @condition is checked each time the waitqueue @wq is woken up.
384  *
385  * wake_up() has to be called after changing any variable that could
386  * change the result of the wait condition.
387  *
388  * The function returns 0 if @condition became true, or -ETIME if the timeout
389  * elapsed.
390  */
391 #define wait_event_hrtimeout(wq, condition, timeout)                    \
392 ({                                                                      \
393         int __ret = 0;                                                  \
394         if (!(condition))                                               \
395                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
396                                                TASK_UNINTERRUPTIBLE);   \
397         __ret;                                                          \
398 })
399 
400 /**
401  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
402  * @wq: the waitqueue to wait on
403  * @condition: a C expression for the event to wait for
404  * @timeout: timeout, as a ktime_t
405  *
406  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
407  * @condition evaluates to true or a signal is received.
408  * The @condition is checked each time the waitqueue @wq is woken up.
409  *
410  * wake_up() has to be called after changing any variable that could
411  * change the result of the wait condition.
412  *
413  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
414  * interrupted by a signal, or -ETIME if the timeout elapsed.
415  */
416 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
417 ({                                                                      \
418         long __ret = 0;                                                 \
419         if (!(condition))                                               \
420                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
421                                                TASK_INTERRUPTIBLE);     \
422         __ret;                                                          \
423 })
424 
425 #define __wait_event_interruptible_exclusive(wq, condition, ret)        \
426 do {                                                                    \
427         DEFINE_WAIT(__wait);                                            \
428                                                                         \
429         for (;;) {                                                      \
430                 prepare_to_wait_exclusive(&wq, &__wait,                 \
431                                         TASK_INTERRUPTIBLE);            \
432                 if (condition) {                                        \
433                         finish_wait(&wq, &__wait);                      \
434                         break;                                          \
435                 }                                                       \
436                 if (!signal_pending(current)) {                         \
437                         schedule();                                     \
438                         continue;                                       \
439                 }                                                       \
440                 ret = -ERESTARTSYS;                                     \
441                 abort_exclusive_wait(&wq, &__wait,                      \
442                                 TASK_INTERRUPTIBLE, NULL);              \
443                 break;                                                  \
444         }                                                               \
445 } while (0)
446 
447 #define wait_event_interruptible_exclusive(wq, condition)               \
448 ({                                                                      \
449         int __ret = 0;                                                  \
450         if (!(condition))                                               \
451                 __wait_event_interruptible_exclusive(wq, condition, __ret);\
452         __ret;                                                          \
453 })
454 
455 
456 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
457 ({                                                                      \
458         int __ret = 0;                                                  \
459         DEFINE_WAIT(__wait);                                            \
460         if (exclusive)                                                  \
461                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
462         do {                                                            \
463                 if (likely(list_empty(&__wait.task_list)))              \
464                         __add_wait_queue_tail(&(wq), &__wait);          \
465                 set_current_state(TASK_INTERRUPTIBLE);                  \
466                 if (signal_pending(current)) {                          \
467                         __ret = -ERESTARTSYS;                           \
468                         break;                                          \
469                 }                                                       \
470                 if (irq)                                                \
471                         spin_unlock_irq(&(wq).lock);                    \
472                 else                                                    \
473                         spin_unlock(&(wq).lock);                        \
474                 schedule();                                             \
475                 if (irq)                                                \
476                         spin_lock_irq(&(wq).lock);                      \
477                 else                                                    \
478                         spin_lock(&(wq).lock);                          \
479         } while (!(condition));                                         \
480         __remove_wait_queue(&(wq), &__wait);                            \
481         __set_current_state(TASK_RUNNING);                              \
482         __ret;                                                          \
483 })
484 
485 
486 /**
487  * wait_event_interruptible_locked - sleep until a condition gets true
488  * @wq: the waitqueue to wait on
489  * @condition: a C expression for the event to wait for
490  *
491  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
492  * @condition evaluates to true or a signal is received.
493  * The @condition is checked each time the waitqueue @wq is woken up.
494  *
495  * It must be called with wq.lock being held.  This spinlock is
496  * unlocked while sleeping but @condition testing is done while lock
497  * is held and when this macro exits the lock is held.
498  *
499  * The lock is locked/unlocked using spin_lock()/spin_unlock()
500  * functions which must match the way they are locked/unlocked outside
501  * of this macro.
502  *
503  * wake_up_locked() has to be called after changing any variable that could
504  * change the result of the wait condition.
505  *
506  * The function will return -ERESTARTSYS if it was interrupted by a
507  * signal and 0 if @condition evaluated to true.
508  */
509 #define wait_event_interruptible_locked(wq, condition)                  \
510         ((condition)                                                    \
511          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
512 
513 /**
514  * wait_event_interruptible_locked_irq - sleep until a condition gets true
515  * @wq: the waitqueue to wait on
516  * @condition: a C expression for the event to wait for
517  *
518  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
519  * @condition evaluates to true or a signal is received.
520  * The @condition is checked each time the waitqueue @wq is woken up.
521  *
522  * It must be called with wq.lock being held.  This spinlock is
523  * unlocked while sleeping but @condition testing is done while lock
524  * is held and when this macro exits the lock is held.
525  *
526  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
527  * functions which must match the way they are locked/unlocked outside
528  * of this macro.
529  *
530  * wake_up_locked() has to be called after changing any variable that could
531  * change the result of the wait condition.
532  *
533  * The function will return -ERESTARTSYS if it was interrupted by a
534  * signal and 0 if @condition evaluated to true.
535  */
536 #define wait_event_interruptible_locked_irq(wq, condition)              \
537         ((condition)                                                    \
538          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
539 
540 /**
541  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
542  * @wq: the waitqueue to wait on
543  * @condition: a C expression for the event to wait for
544  *
545  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
546  * @condition evaluates to true or a signal is received.
547  * The @condition is checked each time the waitqueue @wq is woken up.
548  *
549  * It must be called with wq.lock being held.  This spinlock is
550  * unlocked while sleeping but @condition testing is done while lock
551  * is held and when this macro exits the lock is held.
552  *
553  * The lock is locked/unlocked using spin_lock()/spin_unlock()
554  * functions which must match the way they are locked/unlocked outside
555  * of this macro.
556  *
557  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
558  * set thus when other process waits process on the list if this
559  * process is awaken further processes are not considered.
560  *
561  * wake_up_locked() has to be called after changing any variable that could
562  * change the result of the wait condition.
563  *
564  * The function will return -ERESTARTSYS if it was interrupted by a
565  * signal and 0 if @condition evaluated to true.
566  */
567 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
568         ((condition)                                                    \
569          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
570 
571 /**
572  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
573  * @wq: the waitqueue to wait on
574  * @condition: a C expression for the event to wait for
575  *
576  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
577  * @condition evaluates to true or a signal is received.
578  * The @condition is checked each time the waitqueue @wq is woken up.
579  *
580  * It must be called with wq.lock being held.  This spinlock is
581  * unlocked while sleeping but @condition testing is done while lock
582  * is held and when this macro exits the lock is held.
583  *
584  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
585  * functions which must match the way they are locked/unlocked outside
586  * of this macro.
587  *
588  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
589  * set thus when other process waits process on the list if this
590  * process is awaken further processes are not considered.
591  *
592  * wake_up_locked() has to be called after changing any variable that could
593  * change the result of the wait condition.
594  *
595  * The function will return -ERESTARTSYS if it was interrupted by a
596  * signal and 0 if @condition evaluated to true.
597  */
598 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
599         ((condition)                                                    \
600          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
601 
602 
603 
604 #define __wait_event_killable(wq, condition, ret)                       \
605 do {                                                                    \
606         DEFINE_WAIT(__wait);                                            \
607                                                                         \
608         for (;;) {                                                      \
609                 prepare_to_wait(&wq, &__wait, TASK_KILLABLE);           \
610                 if (condition)                                          \
611                         break;                                          \
612                 if (!fatal_signal_pending(current)) {                   \
613                         schedule();                                     \
614                         continue;                                       \
615                 }                                                       \
616                 ret = -ERESTARTSYS;                                     \
617                 break;                                                  \
618         }                                                               \
619         finish_wait(&wq, &__wait);                                      \
620 } while (0)
621 
622 /**
623  * wait_event_killable - sleep until a condition gets true
624  * @wq: the waitqueue to wait on
625  * @condition: a C expression for the event to wait for
626  *
627  * The process is put to sleep (TASK_KILLABLE) until the
628  * @condition evaluates to true or a signal is received.
629  * The @condition is checked each time the waitqueue @wq is woken up.
630  *
631  * wake_up() has to be called after changing any variable that could
632  * change the result of the wait condition.
633  *
634  * The function will return -ERESTARTSYS if it was interrupted by a
635  * signal and 0 if @condition evaluated to true.
636  */
637 #define wait_event_killable(wq, condition)                              \
638 ({                                                                      \
639         int __ret = 0;                                                  \
640         if (!(condition))                                               \
641                 __wait_event_killable(wq, condition, __ret);            \
642         __ret;                                                          \
643 })
644 
645 
646 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
647 do {                                                                    \
648         DEFINE_WAIT(__wait);                                            \
649                                                                         \
650         for (;;) {                                                      \
651                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
652                 if (condition)                                          \
653                         break;                                          \
654                 spin_unlock_irq(&lock);                                 \
655                 cmd;                                                    \
656                 schedule();                                             \
657                 spin_lock_irq(&lock);                                   \
658         }                                                               \
659         finish_wait(&wq, &__wait);                                      \
660 } while (0)
661 
662 /**
663  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
664  *                           condition is checked under the lock. This
665  *                           is expected to be called with the lock
666  *                           taken.
667  * @wq: the waitqueue to wait on
668  * @condition: a C expression for the event to wait for
669  * @lock: a locked spinlock_t, which will be released before cmd
670  *        and schedule() and reacquired afterwards.
671  * @cmd: a command which is invoked outside the critical section before
672  *       sleep
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 invoking the cmd and going to sleep and is reacquired
683  * afterwards.
684  */
685 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
686 do {                                                                    \
687         if (condition)                                                  \
688                 break;                                                  \
689         __wait_event_lock_irq(wq, condition, lock, cmd);                \
690 } while (0)
691 
692 /**
693  * wait_event_lock_irq - sleep until a condition gets true. The
694  *                       condition is checked under the lock. This
695  *                       is expected to be called with the lock
696  *                       taken.
697  * @wq: the waitqueue to wait on
698  * @condition: a C expression for the event to wait for
699  * @lock: a locked spinlock_t, which will be released before schedule()
700  *        and reacquired afterwards.
701  *
702  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
703  * @condition evaluates to true. The @condition is checked each time
704  * the waitqueue @wq is woken up.
705  *
706  * wake_up() has to be called after changing any variable that could
707  * change the result of the wait condition.
708  *
709  * This is supposed to be called while holding the lock. The lock is
710  * dropped before going to sleep and is reacquired afterwards.
711  */
712 #define wait_event_lock_irq(wq, condition, lock)                        \
713 do {                                                                    \
714         if (condition)                                                  \
715                 break;                                                  \
716         __wait_event_lock_irq(wq, condition, lock, );                   \
717 } while (0)
718 
719 
720 #define __wait_event_interruptible_lock_irq(wq, condition,              \
721                                             lock, ret, cmd)             \
722 do {                                                                    \
723         DEFINE_WAIT(__wait);                                            \
724                                                                         \
725         for (;;) {                                                      \
726                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
727                 if (condition)                                          \
728                         break;                                          \
729                 if (signal_pending(current)) {                          \
730                         ret = -ERESTARTSYS;                             \
731                         break;                                          \
732                 }                                                       \
733                 spin_unlock_irq(&lock);                                 \
734                 cmd;                                                    \
735                 schedule();                                             \
736                 spin_lock_irq(&lock);                                   \
737         }                                                               \
738         finish_wait(&wq, &__wait);                                      \
739 } while (0)
740 
741 /**
742  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
743  *              The condition is checked under the lock. This is expected to
744  *              be called with the lock taken.
745  * @wq: the waitqueue to wait on
746  * @condition: a C expression for the event to wait for
747  * @lock: a locked spinlock_t, which will be released before cmd and
748  *        schedule() and reacquired afterwards.
749  * @cmd: a command which is invoked outside the critical section before
750  *       sleep
751  *
752  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
753  * @condition evaluates to true or a signal is received. The @condition is
754  * checked each time the waitqueue @wq is woken up.
755  *
756  * wake_up() has to be called after changing any variable that could
757  * change the result of the wait condition.
758  *
759  * This is supposed to be called while holding the lock. The lock is
760  * dropped before invoking the cmd and going to sleep and is reacquired
761  * afterwards.
762  *
763  * The macro will return -ERESTARTSYS if it was interrupted by a signal
764  * and 0 if @condition evaluated to true.
765  */
766 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
767 ({                                                                      \
768         int __ret = 0;                                                  \
769                                                                         \
770         if (!(condition))                                               \
771                 __wait_event_interruptible_lock_irq(wq, condition,      \
772                                                     lock, __ret, cmd);  \
773         __ret;                                                          \
774 })
775 
776 /**
777  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
778  *              The condition is checked under the lock. This is expected
779  *              to be called with the lock taken.
780  * @wq: the waitqueue to wait on
781  * @condition: a C expression for the event to wait for
782  * @lock: a locked spinlock_t, which will be released before schedule()
783  *        and reacquired afterwards.
784  *
785  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
786  * @condition evaluates to true or signal is received. The @condition is
787  * checked each time the waitqueue @wq is woken up.
788  *
789  * wake_up() has to be called after changing any variable that could
790  * change the result of the wait condition.
791  *
792  * This is supposed to be called while holding the lock. The lock is
793  * dropped before going to sleep and is reacquired afterwards.
794  *
795  * The macro will return -ERESTARTSYS if it was interrupted by a signal
796  * and 0 if @condition evaluated to true.
797  */
798 #define wait_event_interruptible_lock_irq(wq, condition, lock)          \
799 ({                                                                      \
800         int __ret = 0;                                                  \
801                                                                         \
802         if (!(condition))                                               \
803                 __wait_event_interruptible_lock_irq(wq, condition,      \
804                                                     lock, __ret, );     \
805         __ret;                                                          \
806 })
807 
808 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
809                                                     lock, ret)          \
810 do {                                                                    \
811         DEFINE_WAIT(__wait);                                            \
812                                                                         \
813         for (;;) {                                                      \
814                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
815                 if (condition)                                          \
816                         break;                                          \
817                 if (signal_pending(current)) {                          \
818                         ret = -ERESTARTSYS;                             \
819                         break;                                          \
820                 }                                                       \
821                 spin_unlock_irq(&lock);                                 \
822                 ret = schedule_timeout(ret);                            \
823                 spin_lock_irq(&lock);                                   \
824                 if (!ret)                                               \
825                         break;                                          \
826         }                                                               \
827         finish_wait(&wq, &__wait);                                      \
828 } while (0)
829 
830 /**
831  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets true or a timeout elapses.
832  *              The condition is checked under the lock. This is expected
833  *              to be called with the lock taken.
834  * @wq: the waitqueue to wait on
835  * @condition: a C expression for the event to wait for
836  * @lock: a locked spinlock_t, which will be released before schedule()
837  *        and reacquired afterwards.
838  * @timeout: timeout, in jiffies
839  *
840  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
841  * @condition evaluates to true or signal is received. The @condition is
842  * checked each time the waitqueue @wq is woken up.
843  *
844  * wake_up() has to be called after changing any variable that could
845  * change the result of the wait condition.
846  *
847  * This is supposed to be called while holding the lock. The lock is
848  * dropped before going to sleep and is reacquired afterwards.
849  *
850  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
851  * was interrupted by a signal, and the remaining jiffies otherwise
852  * if the condition evaluated to true before the timeout elapsed.
853  */
854 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
855                                                   timeout)              \
856 ({                                                                      \
857         int __ret = timeout;                                            \
858                                                                         \
859         if (!(condition))                                               \
860                 __wait_event_interruptible_lock_irq_timeout(            \
861                                         wq, condition, lock, __ret);    \
862         __ret;                                                          \
863 })
864 
865 
866 /*
867  * These are the old interfaces to sleep waiting for an event.
868  * They are racy.  DO NOT use them, use the wait_event* interfaces above.
869  * We plan to remove these interfaces.
870  */
871 extern void sleep_on(wait_queue_head_t *q);
872 extern long sleep_on_timeout(wait_queue_head_t *q,
873                                       signed long timeout);
874 extern void interruptible_sleep_on(wait_queue_head_t *q);
875 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
876                                            signed long timeout);
877 
878 /*
879  * Waitqueues which are removed from the waitqueue_head at wakeup time
880  */
881 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
882 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
883 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
884 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
885                         unsigned int mode, void *key);
886 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
887 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
888 
889 #define DEFINE_WAIT_FUNC(name, function)                                \
890         wait_queue_t name = {                                           \
891                 .private        = current,                              \
892                 .func           = function,                             \
893                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
894         }
895 
896 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
897 
898 #define DEFINE_WAIT_BIT(name, word, bit)                                \
899         struct wait_bit_queue name = {                                  \
900                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
901                 .wait   = {                                             \
902                         .private        = current,                      \
903                         .func           = wake_bit_function,            \
904                         .task_list      =                               \
905                                 LIST_HEAD_INIT((name).wait.task_list),  \
906                 },                                                      \
907         }
908 
909 #define init_wait(wait)                                                 \
910         do {                                                            \
911                 (wait)->private = current;                              \
912                 (wait)->func = autoremove_wake_function;                \
913                 INIT_LIST_HEAD(&(wait)->task_list);                     \
914                 (wait)->flags = 0;                                      \
915         } while (0)
916 
917 /**
918  * wait_on_bit - wait for a bit to be cleared
919  * @word: the word being waited on, a kernel virtual address
920  * @bit: the bit of the word being waited on
921  * @action: the function used to sleep, which may take special actions
922  * @mode: the task state to sleep in
923  *
924  * There is a standard hashed waitqueue table for generic use. This
925  * is the part of the hashtable's accessor API that waits on a bit.
926  * For instance, if one were to have waiters on a bitflag, one would
927  * call wait_on_bit() in threads waiting for the bit to clear.
928  * One uses wait_on_bit() where one is waiting for the bit to clear,
929  * but has no intention of setting it.
930  */
931 static inline int wait_on_bit(void *word, int bit,
932                                 int (*action)(void *), unsigned mode)
933 {
934         if (!test_bit(bit, word))
935                 return 0;
936         return out_of_line_wait_on_bit(word, bit, action, mode);
937 }
938 
939 /**
940  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
941  * @word: the word being waited on, a kernel virtual address
942  * @bit: the bit of the word being waited on
943  * @action: the function used to sleep, which may take special actions
944  * @mode: the task state to sleep in
945  *
946  * There is a standard hashed waitqueue table for generic use. This
947  * is the part of the hashtable's accessor API that waits on a bit
948  * when one intends to set it, for instance, trying to lock bitflags.
949  * For instance, if one were to have waiters trying to set bitflag
950  * and waiting for it to clear before setting it, one would call
951  * wait_on_bit() in threads waiting to be able to set the bit.
952  * One uses wait_on_bit_lock() where one is waiting for the bit to
953  * clear with the intention of setting it, and when done, clearing it.
954  */
955 static inline int wait_on_bit_lock(void *word, int bit,
956                                 int (*action)(void *), unsigned mode)
957 {
958         if (!test_and_set_bit(bit, word))
959                 return 0;
960         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
961 }
962         
963 #endif
964 

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