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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 #define WNOHANG         0x00000001
  5 #define WUNTRACED       0x00000002
  6 #define WSTOPPED        WUNTRACED
  7 #define WEXITED         0x00000004
  8 #define WCONTINUED      0x00000008
  9 #define WNOWAIT         0x01000000      /* Don't reap, just poll status.  */
 10 
 11 #define __WNOTHREAD     0x20000000      /* Don't wait on children of other threads in this group */
 12 #define __WALL          0x40000000      /* Wait on all children, regardless of type */
 13 #define __WCLONE        0x80000000      /* Wait only on non-SIGCHLD children */
 14 
 15 /* First argument to waitid: */
 16 #define P_ALL           0
 17 #define P_PID           1
 18 #define P_PGID          2
 19 
 20 #ifdef __KERNEL__
 21 
 22 #include <linux/list.h>
 23 #include <linux/stddef.h>
 24 #include <linux/spinlock.h>
 25 #include <asm/system.h>
 26 #include <asm/current.h>
 27 
 28 typedef struct __wait_queue wait_queue_t;
 29 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key);
 30 int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, void *key);
 31 
 32 struct __wait_queue {
 33         unsigned int flags;
 34 #define WQ_FLAG_EXCLUSIVE       0x01
 35         void *private;
 36         wait_queue_func_t func;
 37         struct list_head task_list;
 38 };
 39 
 40 struct wait_bit_key {
 41         void *flags;
 42         int bit_nr;
 43 };
 44 
 45 struct wait_bit_queue {
 46         struct wait_bit_key key;
 47         wait_queue_t wait;
 48 };
 49 
 50 struct __wait_queue_head {
 51         spinlock_t lock;
 52         struct list_head task_list;
 53 };
 54 typedef struct __wait_queue_head wait_queue_head_t;
 55 
 56 struct task_struct;
 57 
 58 /*
 59  * Macros for declaration and initialisaton of the datatypes
 60  */
 61 
 62 #define __WAITQUEUE_INITIALIZER(name, tsk) {                            \
 63         .private        = tsk,                                          \
 64         .func           = default_wake_function,                        \
 65         .task_list      = { NULL, NULL } }
 66 
 67 #define DECLARE_WAITQUEUE(name, tsk)                                    \
 68         wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
 69 
 70 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                           \
 71         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),              \
 72         .task_list      = { &(name).task_list, &(name).task_list } }
 73 
 74 #define DECLARE_WAIT_QUEUE_HEAD(name) \
 75         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
 76 
 77 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)                           \
 78         { .flags = word, .bit_nr = bit, }
 79 
 80 extern void __init_waitqueue_head(wait_queue_head_t *q, struct lock_class_key *);
 81 
 82 #define init_waitqueue_head(q)                          \
 83         do {                                            \
 84                 static struct lock_class_key __key;     \
 85                                                         \
 86                 __init_waitqueue_head((q), &__key);     \
 87         } while (0)
 88 
 89 #ifdef CONFIG_LOCKDEP
 90 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
 91         ({ init_waitqueue_head(&name); name; })
 92 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
 93         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
 94 #else
 95 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
 96 #endif
 97 
 98 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
 99 {
100         q->flags = 0;
101         q->private = p;
102         q->func = default_wake_function;
103 }
104 
105 static inline void init_waitqueue_func_entry(wait_queue_t *q,
106                                         wait_queue_func_t func)
107 {
108         q->flags = 0;
109         q->private = NULL;
110         q->func = func;
111 }
112 
113 static inline int waitqueue_active(wait_queue_head_t *q)
114 {
115         return !list_empty(&q->task_list);
116 }
117 
118 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
119 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
120 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
121 
122 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
123 {
124         list_add(&new->task_list, &head->task_list);
125 }
126 
127 /*
128  * Used for wake-one threads:
129  */
130 static inline void __add_wait_queue_exclusive(wait_queue_head_t *q,
131                                               wait_queue_t *wait)
132 {
133         wait->flags |= WQ_FLAG_EXCLUSIVE;
134         __add_wait_queue(q, wait);
135 }
136 
137 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
138                                          wait_queue_t *new)
139 {
140         list_add_tail(&new->task_list, &head->task_list);
141 }
142 
143 static inline void __add_wait_queue_tail_exclusive(wait_queue_head_t *q,
144                                               wait_queue_t *wait)
145 {
146         wait->flags |= WQ_FLAG_EXCLUSIVE;
147         __add_wait_queue_tail(q, wait);
148 }
149 
150 static inline void __remove_wait_queue(wait_queue_head_t *head,
151                                                         wait_queue_t *old)
152 {
153         list_del(&old->task_list);
154 }
155 
156 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
157 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
158 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr,
159                         void *key);
160 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode);
161 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
162 void __wake_up_bit(wait_queue_head_t *, void *, int);
163 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
164 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
165 void wake_up_bit(void *, int);
166 int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned);
167 int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned);
168 wait_queue_head_t *bit_waitqueue(void *, int);
169 
170 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
171 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
172 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
173 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL)
174 
175 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
176 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
177 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
178 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
179 
180 /*
181  * Wakeup macros to be used to report events to the targets.
182  */
183 #define wake_up_poll(x, m)                              \
184         __wake_up(x, TASK_NORMAL, 1, (void *) (m))
185 #define wake_up_locked_poll(x, m)                               \
186         __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
187 #define wake_up_interruptible_poll(x, m)                        \
188         __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
189 #define wake_up_interruptible_sync_poll(x, m)                           \
190         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
191 
192 #define __wait_event(wq, condition)                                     \
193 do {                                                                    \
194         DEFINE_WAIT(__wait);                                            \
195                                                                         \
196         for (;;) {                                                      \
197                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
198                 if (condition)                                          \
199                         break;                                          \
200                 schedule();                                             \
201         }                                                               \
202         finish_wait(&wq, &__wait);                                      \
203 } while (0)
204 
205 /**
206  * wait_event - sleep until a condition gets true
207  * @wq: the waitqueue to wait on
208  * @condition: a C expression for the event to wait for
209  *
210  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
211  * @condition evaluates to true. The @condition is checked each time
212  * the waitqueue @wq is woken up.
213  *
214  * wake_up() has to be called after changing any variable that could
215  * change the result of the wait condition.
216  */
217 #define wait_event(wq, condition)                                       \
218 do {                                                                    \
219         if (condition)                                                  \
220                 break;                                                  \
221         __wait_event(wq, condition);                                    \
222 } while (0)
223 
224 #define __wait_event_timeout(wq, condition, ret)                        \
225 do {                                                                    \
226         DEFINE_WAIT(__wait);                                            \
227                                                                         \
228         for (;;) {                                                      \
229                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
230                 if (condition)                                          \
231                         break;                                          \
232                 ret = schedule_timeout(ret);                            \
233                 if (!ret)                                               \
234                         break;                                          \
235         }                                                               \
236         if (!ret && (condition))                                        \
237                 ret = 1;                                                \
238         finish_wait(&wq, &__wait);                                      \
239 } while (0)
240 
241 /**
242  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
243  * @wq: the waitqueue to wait on
244  * @condition: a C expression for the event to wait for
245  * @timeout: timeout, in jiffies
246  *
247  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
248  * @condition evaluates to true. The @condition is checked each time
249  * the waitqueue @wq is woken up.
250  *
251  * wake_up() has to be called after changing any variable that could
252  * change the result of the wait condition.
253  *
254  * The function returns 0 if the @timeout elapsed, or the remaining
255  * jiffies (at least 1) if the @condition evaluated to %true before
256  * the @timeout elapsed.
257  */
258 #define wait_event_timeout(wq, condition, timeout)                      \
259 ({                                                                      \
260         long __ret = timeout;                                           \
261         if (!(condition))                                               \
262                 __wait_event_timeout(wq, condition, __ret);             \
263         __ret;                                                          \
264 })
265 
266 #define __wait_event_interruptible(wq, condition, ret)                  \
267 do {                                                                    \
268         DEFINE_WAIT(__wait);                                            \
269                                                                         \
270         for (;;) {                                                      \
271                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
272                 if (condition)                                          \
273                         break;                                          \
274                 if (!signal_pending(current)) {                         \
275                         schedule();                                     \
276                         continue;                                       \
277                 }                                                       \
278                 ret = -ERESTARTSYS;                                     \
279                 break;                                                  \
280         }                                                               \
281         finish_wait(&wq, &__wait);                                      \
282 } while (0)
283 
284 /**
285  * wait_event_interruptible - sleep until a condition gets true
286  * @wq: the waitqueue to wait on
287  * @condition: a C expression for the event to wait for
288  *
289  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
290  * @condition evaluates to true or a signal is received.
291  * The @condition is checked each time the waitqueue @wq is woken up.
292  *
293  * wake_up() has to be called after changing any variable that could
294  * change the result of the wait condition.
295  *
296  * The function will return -ERESTARTSYS if it was interrupted by a
297  * signal and 0 if @condition evaluated to true.
298  */
299 #define wait_event_interruptible(wq, condition)                         \
300 ({                                                                      \
301         int __ret = 0;                                                  \
302         if (!(condition))                                               \
303                 __wait_event_interruptible(wq, condition, __ret);       \
304         __ret;                                                          \
305 })
306 
307 #define __wait_event_interruptible_timeout(wq, condition, ret)          \
308 do {                                                                    \
309         DEFINE_WAIT(__wait);                                            \
310                                                                         \
311         for (;;) {                                                      \
312                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
313                 if (condition)                                          \
314                         break;                                          \
315                 if (!signal_pending(current)) {                         \
316                         ret = schedule_timeout(ret);                    \
317                         if (!ret)                                       \
318                                 break;                                  \
319                         continue;                                       \
320                 }                                                       \
321                 ret = -ERESTARTSYS;                                     \
322                 break;                                                  \
323         }                                                               \
324         if (!ret && (condition))                                        \
325                 ret = 1;                                                \
326         finish_wait(&wq, &__wait);                                      \
327 } while (0)
328 
329 /**
330  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
331  * @wq: the waitqueue to wait on
332  * @condition: a C expression for the event to wait for
333  * @timeout: timeout, in jiffies
334  *
335  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
336  * @condition evaluates to true or a signal is received.
337  * The @condition is checked each time the waitqueue @wq is woken up.
338  *
339  * wake_up() has to be called after changing any variable that could
340  * change the result of the wait condition.
341  *
342  * Returns:
343  * 0 if the @timeout elapsed, -%ERESTARTSYS if it was interrupted by
344  * a signal, or the remaining jiffies (at least 1) if the @condition
345  * evaluated to %true before the @timeout elapsed.
346  */
347 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
348 ({                                                                      \
349         long __ret = timeout;                                           \
350         if (!(condition))                                               \
351                 __wait_event_interruptible_timeout(wq, condition, __ret); \
352         __ret;                                                          \
353 })
354 
355 #define __wait_event_interruptible_exclusive(wq, condition, ret)        \
356 do {                                                                    \
357         DEFINE_WAIT(__wait);                                            \
358                                                                         \
359         for (;;) {                                                      \
360                 prepare_to_wait_exclusive(&wq, &__wait,                 \
361                                         TASK_INTERRUPTIBLE);            \
362                 if (condition) {                                        \
363                         finish_wait(&wq, &__wait);                      \
364                         break;                                          \
365                 }                                                       \
366                 if (!signal_pending(current)) {                         \
367                         schedule();                                     \
368                         continue;                                       \
369                 }                                                       \
370                 ret = -ERESTARTSYS;                                     \
371                 abort_exclusive_wait(&wq, &__wait,                      \
372                                 TASK_INTERRUPTIBLE, NULL);              \
373                 break;                                                  \
374         }                                                               \
375 } while (0)
376 
377 #define wait_event_interruptible_exclusive(wq, condition)               \
378 ({                                                                      \
379         int __ret = 0;                                                  \
380         if (!(condition))                                               \
381                 __wait_event_interruptible_exclusive(wq, condition, __ret);\
382         __ret;                                                          \
383 })
384 
385 
386 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
387 ({                                                                      \
388         int __ret = 0;                                                  \
389         DEFINE_WAIT(__wait);                                            \
390         if (exclusive)                                                  \
391                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
392         do {                                                            \
393                 if (likely(list_empty(&__wait.task_list)))              \
394                         __add_wait_queue_tail(&(wq), &__wait);          \
395                 set_current_state(TASK_INTERRUPTIBLE);                  \
396                 if (signal_pending(current)) {                          \
397                         __ret = -ERESTARTSYS;                           \
398                         break;                                          \
399                 }                                                       \
400                 if (irq)                                                \
401                         spin_unlock_irq(&(wq).lock);                    \
402                 else                                                    \
403                         spin_unlock(&(wq).lock);                        \
404                 schedule();                                             \
405                 if (irq)                                                \
406                         spin_lock_irq(&(wq).lock);                      \
407                 else                                                    \
408                         spin_lock(&(wq).lock);                          \
409         } while (!(condition));                                         \
410         __remove_wait_queue(&(wq), &__wait);                            \
411         __set_current_state(TASK_RUNNING);                              \
412         __ret;                                                          \
413 })
414 
415 
416 /**
417  * wait_event_interruptible_locked - sleep until a condition gets true
418  * @wq: the waitqueue to wait on
419  * @condition: a C expression for the event to wait for
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  * It must be called with wq.lock being held.  This spinlock is
426  * unlocked while sleeping but @condition testing is done while lock
427  * is held and when this macro exits the lock is held.
428  *
429  * The lock is locked/unlocked using spin_lock()/spin_unlock()
430  * functions which must match the way they are locked/unlocked outside
431  * of this macro.
432  *
433  * wake_up_locked() has to be called after changing any variable that could
434  * change the result of the wait condition.
435  *
436  * The function will return -ERESTARTSYS if it was interrupted by a
437  * signal and 0 if @condition evaluated to true.
438  */
439 #define wait_event_interruptible_locked(wq, condition)                  \
440         ((condition)                                                    \
441          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
442 
443 /**
444  * wait_event_interruptible_locked_irq - sleep until a condition gets true
445  * @wq: the waitqueue to wait on
446  * @condition: a C expression for the event to wait for
447  *
448  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
449  * @condition evaluates to true or a signal is received.
450  * The @condition is checked each time the waitqueue @wq is woken up.
451  *
452  * It must be called with wq.lock being held.  This spinlock is
453  * unlocked while sleeping but @condition testing is done while lock
454  * is held and when this macro exits the lock is held.
455  *
456  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
457  * functions which must match the way they are locked/unlocked outside
458  * of this macro.
459  *
460  * wake_up_locked() has to be called after changing any variable that could
461  * change the result of the wait condition.
462  *
463  * The function will return -ERESTARTSYS if it was interrupted by a
464  * signal and 0 if @condition evaluated to true.
465  */
466 #define wait_event_interruptible_locked_irq(wq, condition)              \
467         ((condition)                                                    \
468          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
469 
470 /**
471  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
472  * @wq: the waitqueue to wait on
473  * @condition: a C expression for the event to wait for
474  *
475  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
476  * @condition evaluates to true or a signal is received.
477  * The @condition is checked each time the waitqueue @wq is woken up.
478  *
479  * It must be called with wq.lock being held.  This spinlock is
480  * unlocked while sleeping but @condition testing is done while lock
481  * is held and when this macro exits the lock is held.
482  *
483  * The lock is locked/unlocked using spin_lock()/spin_unlock()
484  * functions which must match the way they are locked/unlocked outside
485  * of this macro.
486  *
487  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
488  * set thus when other process waits process on the list if this
489  * process is awaken further processes are not considered.
490  *
491  * wake_up_locked() has to be called after changing any variable that could
492  * change the result of the wait condition.
493  *
494  * The function will return -ERESTARTSYS if it was interrupted by a
495  * signal and 0 if @condition evaluated to true.
496  */
497 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
498         ((condition)                                                    \
499          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
500 
501 /**
502  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
503  * @wq: the waitqueue to wait on
504  * @condition: a C expression for the event to wait for
505  *
506  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
507  * @condition evaluates to true or a signal is received.
508  * The @condition is checked each time the waitqueue @wq is woken up.
509  *
510  * It must be called with wq.lock being held.  This spinlock is
511  * unlocked while sleeping but @condition testing is done while lock
512  * is held and when this macro exits the lock is held.
513  *
514  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
515  * functions which must match the way they are locked/unlocked outside
516  * of this macro.
517  *
518  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
519  * set thus when other process waits process on the list if this
520  * process is awaken further processes are not considered.
521  *
522  * wake_up_locked() has to be called after changing any variable that could
523  * change the result of the wait condition.
524  *
525  * The function will return -ERESTARTSYS if it was interrupted by a
526  * signal and 0 if @condition evaluated to true.
527  */
528 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
529         ((condition)                                                    \
530          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
531 
532 
533 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
534                                                     lock, ret)          \
535 do {                                                                    \
536         DEFINE_WAIT(__wait);                                            \
537                                                                         \
538         for (;;) {                                                      \
539                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
540                 if (condition)                                          \
541                         break;                                          \
542                 if (signal_pending(current)) {                          \
543                         ret = -ERESTARTSYS;                             \
544                         break;                                          \
545                 }                                                       \
546                 spin_unlock_irq(&lock);                                 \
547                 ret = schedule_timeout(ret);                            \
548                 spin_lock_irq(&lock);                                   \
549                 if (!ret)                                               \
550                         break;                                          \
551         }                                                               \
552         finish_wait(&wq, &__wait);                                      \
553 } while (0)
554 
555 /**
556  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets true or a timeout elapses.
557  *              The condition is checked under the lock. This is expected
558  *              to be called with the lock taken.
559  * @wq: the waitqueue to wait on
560  * @condition: a C expression for the event to wait for
561  * @lock: a locked spinlock_t, which will be released before schedule()
562  *        and reacquired afterwards.
563  * @timeout: timeout, in jiffies
564  *
565  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
566  * @condition evaluates to true or signal is received. The @condition is
567  * checked each time the waitqueue @wq is woken up.
568  *
569  * wake_up() has to be called after changing any variable that could
570  * change the result of the wait condition.
571  *
572  * This is supposed to be called while holding the lock. The lock is
573  * dropped before going to sleep and is reacquired afterwards.
574  *
575  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
576  * was interrupted by a signal, and the remaining jiffies otherwise
577  * if the condition evaluated to true before the timeout elapsed.
578  */
579 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
580                                                   timeout)              \
581 ({                                                                      \
582         int __ret = timeout;                                            \
583                                                                         \
584         if (!(condition))                                               \
585                 __wait_event_interruptible_lock_irq_timeout(            \
586                                         wq, condition, lock, __ret);    \
587         __ret;                                                          \
588 })
589 
590 
591 #define __wait_event_killable(wq, condition, ret)                       \
592 do {                                                                    \
593         DEFINE_WAIT(__wait);                                            \
594                                                                         \
595         for (;;) {                                                      \
596                 prepare_to_wait(&wq, &__wait, TASK_KILLABLE);           \
597                 if (condition)                                          \
598                         break;                                          \
599                 if (!fatal_signal_pending(current)) {                   \
600                         schedule();                                     \
601                         continue;                                       \
602                 }                                                       \
603                 ret = -ERESTARTSYS;                                     \
604                 break;                                                  \
605         }                                                               \
606         finish_wait(&wq, &__wait);                                      \
607 } while (0)
608 
609 /**
610  * wait_event_killable - sleep until a condition gets true
611  * @wq: the waitqueue to wait on
612  * @condition: a C expression for the event to wait for
613  *
614  * The process is put to sleep (TASK_KILLABLE) until the
615  * @condition evaluates to true or a signal is received.
616  * The @condition is checked each time the waitqueue @wq is woken up.
617  *
618  * wake_up() has to be called after changing any variable that could
619  * change the result of the wait condition.
620  *
621  * The function will return -ERESTARTSYS if it was interrupted by a
622  * signal and 0 if @condition evaluated to true.
623  */
624 #define wait_event_killable(wq, condition)                              \
625 ({                                                                      \
626         int __ret = 0;                                                  \
627         if (!(condition))                                               \
628                 __wait_event_killable(wq, condition, __ret);            \
629         __ret;                                                          \
630 })
631 
632 /*
633  * These are the old interfaces to sleep waiting for an event.
634  * They are racy.  DO NOT use them, use the wait_event* interfaces above.
635  * We plan to remove these interfaces.
636  */
637 extern void sleep_on(wait_queue_head_t *q);
638 extern long sleep_on_timeout(wait_queue_head_t *q,
639                                       signed long timeout);
640 extern void interruptible_sleep_on(wait_queue_head_t *q);
641 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
642                                            signed long timeout);
643 
644 /*
645  * Waitqueues which are removed from the waitqueue_head at wakeup time
646  */
647 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
648 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
649 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
650 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
651                         unsigned int mode, void *key);
652 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
653 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
654 
655 #define DEFINE_WAIT_FUNC(name, function)                                \
656         wait_queue_t name = {                                           \
657                 .private        = current,                              \
658                 .func           = function,                             \
659                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
660         }
661 
662 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
663 
664 #define DEFINE_WAIT_BIT(name, word, bit)                                \
665         struct wait_bit_queue name = {                                  \
666                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
667                 .wait   = {                                             \
668                         .private        = current,                      \
669                         .func           = wake_bit_function,            \
670                         .task_list      =                               \
671                                 LIST_HEAD_INIT((name).wait.task_list),  \
672                 },                                                      \
673         }
674 
675 #define init_wait(wait)                                                 \
676         do {                                                            \
677                 (wait)->private = current;                              \
678                 (wait)->func = autoremove_wake_function;                \
679                 INIT_LIST_HEAD(&(wait)->task_list);                     \
680                 (wait)->flags = 0;                                      \
681         } while (0)
682 
683 /**
684  * wait_on_bit - wait for a bit to be cleared
685  * @word: the word being waited on, a kernel virtual address
686  * @bit: the bit of the word being waited on
687  * @action: the function used to sleep, which may take special actions
688  * @mode: the task state to sleep in
689  *
690  * There is a standard hashed waitqueue table for generic use. This
691  * is the part of the hashtable's accessor API that waits on a bit.
692  * For instance, if one were to have waiters on a bitflag, one would
693  * call wait_on_bit() in threads waiting for the bit to clear.
694  * One uses wait_on_bit() where one is waiting for the bit to clear,
695  * but has no intention of setting it.
696  */
697 static inline int wait_on_bit(void *word, int bit,
698                                 int (*action)(void *), unsigned mode)
699 {
700         if (!test_bit(bit, word))
701                 return 0;
702         return out_of_line_wait_on_bit(word, bit, action, mode);
703 }
704 
705 /**
706  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
707  * @word: the word being waited on, a kernel virtual address
708  * @bit: the bit of the word being waited on
709  * @action: the function used to sleep, which may take special actions
710  * @mode: the task state to sleep in
711  *
712  * There is a standard hashed waitqueue table for generic use. This
713  * is the part of the hashtable's accessor API that waits on a bit
714  * when one intends to set it, for instance, trying to lock bitflags.
715  * For instance, if one were to have waiters trying to set bitflag
716  * and waiting for it to clear before setting it, one would call
717  * wait_on_bit() in threads waiting to be able to set the bit.
718  * One uses wait_on_bit_lock() where one is waiting for the bit to
719  * clear with the intention of setting it, and when done, clearing it.
720  */
721 static inline int wait_on_bit_lock(void *word, int bit,
722                                 int (*action)(void *), unsigned mode)
723 {
724         if (!test_and_set_bit(bit, word))
725                 return 0;
726         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
727 }
728         
729 #endif /* __KERNEL__ */
730 
731 #endif
732 

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