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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 /*
195  * The below macro ___wait_event() has an explicit shadow of the __ret
196  * variable when used from the wait_event_*() macros.
197  *
198  * This is so that both can use the ___wait_cond_timeout() construct
199  * to wrap the condition.
200  *
201  * The type inconsistency of the wait_event_*() __ret variable is also
202  * on purpose; we use long where we can return timeout values and int
203  * otherwise.
204  */
205 
206 #define ___wait_event(wq, condition, state, exclusive, ret, cmd)        \
207 ({                                                                      \
208         __label__ __out;                                                \
209         wait_queue_t __wait;                                            \
210         long __ret = ret;       /* explicit shadow */                   \
211                                                                         \
212         INIT_LIST_HEAD(&__wait.task_list);                              \
213         if (exclusive)                                                  \
214                 __wait.flags = WQ_FLAG_EXCLUSIVE;                       \
215         else                                                            \
216                 __wait.flags = 0;                                       \
217                                                                         \
218         for (;;) {                                                      \
219                 long __int = prepare_to_wait_event(&wq, &__wait, state);\
220                                                                         \
221                 if (condition)                                          \
222                         break;                                          \
223                                                                         \
224                 if (___wait_is_interruptible(state) && __int) {         \
225                         __ret = __int;                                  \
226                         if (exclusive) {                                \
227                                 abort_exclusive_wait(&wq, &__wait,      \
228                                                      state, NULL);      \
229                                 goto __out;                             \
230                         }                                               \
231                         break;                                          \
232                 }                                                       \
233                                                                         \
234                 cmd;                                                    \
235         }                                                               \
236         finish_wait(&wq, &__wait);                                      \
237 __out:  __ret;                                                          \
238 })
239 
240 #define __wait_event(wq, condition)                                     \
241         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
242                             schedule())
243 
244 /**
245  * wait_event - sleep until a condition gets true
246  * @wq: the waitqueue to wait on
247  * @condition: a C expression for the event to wait for
248  *
249  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
250  * @condition evaluates to true. The @condition is checked each time
251  * the waitqueue @wq is woken up.
252  *
253  * wake_up() has to be called after changing any variable that could
254  * change the result of the wait condition.
255  */
256 #define wait_event(wq, condition)                                       \
257 do {                                                                    \
258         if (condition)                                                  \
259                 break;                                                  \
260         __wait_event(wq, condition);                                    \
261 } while (0)
262 
263 #define __wait_event_timeout(wq, condition, timeout)                    \
264         ___wait_event(wq, ___wait_cond_timeout(condition),              \
265                       TASK_UNINTERRUPTIBLE, 0, timeout,                 \
266                       __ret = schedule_timeout(__ret))
267 
268 /**
269  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
270  * @wq: the waitqueue to wait on
271  * @condition: a C expression for the event to wait for
272  * @timeout: timeout, in jiffies
273  *
274  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
275  * @condition evaluates to true. The @condition is checked each time
276  * the waitqueue @wq is woken up.
277  *
278  * wake_up() has to be called after changing any variable that could
279  * change the result of the wait condition.
280  *
281  * The function returns 0 if the @timeout elapsed, or the remaining
282  * jiffies (at least 1) if the @condition evaluated to %true before
283  * the @timeout elapsed.
284  */
285 #define wait_event_timeout(wq, condition, timeout)                      \
286 ({                                                                      \
287         long __ret = timeout;                                           \
288         if (!___wait_cond_timeout(condition))                           \
289                 __ret = __wait_event_timeout(wq, condition, timeout);   \
290         __ret;                                                          \
291 })
292 
293 #define __wait_event_cmd(wq, condition, cmd1, cmd2)                     \
294         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
295                             cmd1; schedule(); cmd2)
296 
297 /**
298  * wait_event_cmd - sleep until a condition gets true
299  * @wq: the waitqueue to wait on
300  * @condition: a C expression for the event to wait for
301  * @cmd1: the command will be executed before sleep
302  * @cmd2: the command will be executed after sleep
303  *
304  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
305  * @condition evaluates to true. The @condition is checked each time
306  * the waitqueue @wq is woken up.
307  *
308  * wake_up() has to be called after changing any variable that could
309  * change the result of the wait condition.
310  */
311 #define wait_event_cmd(wq, condition, cmd1, cmd2)                       \
312 do {                                                                    \
313         if (condition)                                                  \
314                 break;                                                  \
315         __wait_event_cmd(wq, condition, cmd1, cmd2);                    \
316 } while (0)
317 
318 #define __wait_event_interruptible(wq, condition)                       \
319         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
320                       schedule())
321 
322 /**
323  * wait_event_interruptible - sleep until a condition gets true
324  * @wq: the waitqueue to wait on
325  * @condition: a C expression for the event to wait for
326  *
327  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
328  * @condition evaluates to true or a signal is received.
329  * The @condition is checked each time the waitqueue @wq is woken up.
330  *
331  * wake_up() has to be called after changing any variable that could
332  * change the result of the wait condition.
333  *
334  * The function will return -ERESTARTSYS if it was interrupted by a
335  * signal and 0 if @condition evaluated to true.
336  */
337 #define wait_event_interruptible(wq, condition)                         \
338 ({                                                                      \
339         int __ret = 0;                                                  \
340         if (!(condition))                                               \
341                 __ret = __wait_event_interruptible(wq, condition);      \
342         __ret;                                                          \
343 })
344 
345 #define __wait_event_interruptible_timeout(wq, condition, timeout)      \
346         ___wait_event(wq, ___wait_cond_timeout(condition),              \
347                       TASK_INTERRUPTIBLE, 0, timeout,                   \
348                       __ret = schedule_timeout(__ret))
349 
350 /**
351  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
352  * @wq: the waitqueue to wait on
353  * @condition: a C expression for the event to wait for
354  * @timeout: timeout, in jiffies
355  *
356  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
357  * @condition evaluates to true or a signal is received.
358  * The @condition is checked each time the waitqueue @wq is woken up.
359  *
360  * wake_up() has to be called after changing any variable that could
361  * change the result of the wait condition.
362  *
363  * Returns:
364  * 0 if the @timeout elapsed, -%ERESTARTSYS if it was interrupted by
365  * a signal, or the remaining jiffies (at least 1) if the @condition
366  * evaluated to %true before the @timeout elapsed.
367  */
368 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
369 ({                                                                      \
370         long __ret = timeout;                                           \
371         if (!___wait_cond_timeout(condition))                           \
372                 __ret = __wait_event_interruptible_timeout(wq,          \
373                                                 condition, timeout);    \
374         __ret;                                                          \
375 })
376 
377 #define __wait_event_hrtimeout(wq, condition, timeout, state)           \
378 ({                                                                      \
379         int __ret = 0;                                                  \
380         struct hrtimer_sleeper __t;                                     \
381                                                                         \
382         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
383                               HRTIMER_MODE_REL);                        \
384         hrtimer_init_sleeper(&__t, current);                            \
385         if ((timeout).tv64 != KTIME_MAX)                                \
386                 hrtimer_start_range_ns(&__t.timer, timeout,             \
387                                        current->timer_slack_ns,         \
388                                        HRTIMER_MODE_REL);               \
389                                                                         \
390         __ret = ___wait_event(wq, condition, state, 0, 0,               \
391                 if (!__t.task) {                                        \
392                         __ret = -ETIME;                                 \
393                         break;                                          \
394                 }                                                       \
395                 schedule());                                            \
396                                                                         \
397         hrtimer_cancel(&__t.timer);                                     \
398         destroy_hrtimer_on_stack(&__t.timer);                           \
399         __ret;                                                          \
400 })
401 
402 /**
403  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
404  * @wq: the waitqueue to wait on
405  * @condition: a C expression for the event to wait for
406  * @timeout: timeout, as a ktime_t
407  *
408  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
409  * @condition evaluates to true or a signal is received.
410  * The @condition is checked each time the waitqueue @wq is woken up.
411  *
412  * wake_up() has to be called after changing any variable that could
413  * change the result of the wait condition.
414  *
415  * The function returns 0 if @condition became true, or -ETIME if the timeout
416  * elapsed.
417  */
418 #define wait_event_hrtimeout(wq, condition, timeout)                    \
419 ({                                                                      \
420         int __ret = 0;                                                  \
421         if (!(condition))                                               \
422                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
423                                                TASK_UNINTERRUPTIBLE);   \
424         __ret;                                                          \
425 })
426 
427 /**
428  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
429  * @wq: the waitqueue to wait on
430  * @condition: a C expression for the event to wait for
431  * @timeout: timeout, as a ktime_t
432  *
433  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
434  * @condition evaluates to true or a signal is received.
435  * The @condition is checked each time the waitqueue @wq is woken up.
436  *
437  * wake_up() has to be called after changing any variable that could
438  * change the result of the wait condition.
439  *
440  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
441  * interrupted by a signal, or -ETIME if the timeout elapsed.
442  */
443 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
444 ({                                                                      \
445         long __ret = 0;                                                 \
446         if (!(condition))                                               \
447                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
448                                                TASK_INTERRUPTIBLE);     \
449         __ret;                                                          \
450 })
451 
452 #define __wait_event_interruptible_exclusive(wq, condition)             \
453         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
454                       schedule())
455 
456 #define wait_event_interruptible_exclusive(wq, condition)               \
457 ({                                                                      \
458         int __ret = 0;                                                  \
459         if (!(condition))                                               \
460                 __ret = __wait_event_interruptible_exclusive(wq, condition);\
461         __ret;                                                          \
462 })
463 
464 
465 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
466 ({                                                                      \
467         int __ret = 0;                                                  \
468         DEFINE_WAIT(__wait);                                            \
469         if (exclusive)                                                  \
470                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
471         do {                                                            \
472                 if (likely(list_empty(&__wait.task_list)))              \
473                         __add_wait_queue_tail(&(wq), &__wait);          \
474                 set_current_state(TASK_INTERRUPTIBLE);                  \
475                 if (signal_pending(current)) {                          \
476                         __ret = -ERESTARTSYS;                           \
477                         break;                                          \
478                 }                                                       \
479                 if (irq)                                                \
480                         spin_unlock_irq(&(wq).lock);                    \
481                 else                                                    \
482                         spin_unlock(&(wq).lock);                        \
483                 schedule();                                             \
484                 if (irq)                                                \
485                         spin_lock_irq(&(wq).lock);                      \
486                 else                                                    \
487                         spin_lock(&(wq).lock);                          \
488         } while (!(condition));                                         \
489         __remove_wait_queue(&(wq), &__wait);                            \
490         __set_current_state(TASK_RUNNING);                              \
491         __ret;                                                          \
492 })
493 
494 
495 /**
496  * wait_event_interruptible_locked - sleep until a condition gets true
497  * @wq: the waitqueue to wait on
498  * @condition: a C expression for the event to wait for
499  *
500  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
501  * @condition evaluates to true or a signal is received.
502  * The @condition is checked each time the waitqueue @wq is woken up.
503  *
504  * It must be called with wq.lock being held.  This spinlock is
505  * unlocked while sleeping but @condition testing is done while lock
506  * is held and when this macro exits the lock is held.
507  *
508  * The lock is locked/unlocked using spin_lock()/spin_unlock()
509  * functions which must match the way they are locked/unlocked outside
510  * of this macro.
511  *
512  * wake_up_locked() has to be called after changing any variable that could
513  * change the result of the wait condition.
514  *
515  * The function will return -ERESTARTSYS if it was interrupted by a
516  * signal and 0 if @condition evaluated to true.
517  */
518 #define wait_event_interruptible_locked(wq, condition)                  \
519         ((condition)                                                    \
520          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
521 
522 /**
523  * wait_event_interruptible_locked_irq - sleep until a condition gets true
524  * @wq: the waitqueue to wait on
525  * @condition: a C expression for the event to wait for
526  *
527  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
528  * @condition evaluates to true or a signal is received.
529  * The @condition is checked each time the waitqueue @wq is woken up.
530  *
531  * It must be called with wq.lock being held.  This spinlock is
532  * unlocked while sleeping but @condition testing is done while lock
533  * is held and when this macro exits the lock is held.
534  *
535  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
536  * functions which must match the way they are locked/unlocked outside
537  * of this macro.
538  *
539  * wake_up_locked() has to be called after changing any variable that could
540  * change the result of the wait condition.
541  *
542  * The function will return -ERESTARTSYS if it was interrupted by a
543  * signal and 0 if @condition evaluated to true.
544  */
545 #define wait_event_interruptible_locked_irq(wq, condition)              \
546         ((condition)                                                    \
547          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
548 
549 /**
550  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
551  * @wq: the waitqueue to wait on
552  * @condition: a C expression for the event to wait for
553  *
554  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
555  * @condition evaluates to true or a signal is received.
556  * The @condition is checked each time the waitqueue @wq is woken up.
557  *
558  * It must be called with wq.lock being held.  This spinlock is
559  * unlocked while sleeping but @condition testing is done while lock
560  * is held and when this macro exits the lock is held.
561  *
562  * The lock is locked/unlocked using spin_lock()/spin_unlock()
563  * functions which must match the way they are locked/unlocked outside
564  * of this macro.
565  *
566  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
567  * set thus when other process waits process on the list if this
568  * process is awaken further processes are not considered.
569  *
570  * wake_up_locked() has to be called after changing any variable that could
571  * change the result of the wait condition.
572  *
573  * The function will return -ERESTARTSYS if it was interrupted by a
574  * signal and 0 if @condition evaluated to true.
575  */
576 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
577         ((condition)                                                    \
578          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
579 
580 /**
581  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
582  * @wq: the waitqueue to wait on
583  * @condition: a C expression for the event to wait for
584  *
585  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
586  * @condition evaluates to true or a signal is received.
587  * The @condition is checked each time the waitqueue @wq is woken up.
588  *
589  * It must be called with wq.lock being held.  This spinlock is
590  * unlocked while sleeping but @condition testing is done while lock
591  * is held and when this macro exits the lock is held.
592  *
593  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
594  * functions which must match the way they are locked/unlocked outside
595  * of this macro.
596  *
597  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
598  * set thus when other process waits process on the list if this
599  * process is awaken further processes are not considered.
600  *
601  * wake_up_locked() has to be called after changing any variable that could
602  * change the result of the wait condition.
603  *
604  * The function will return -ERESTARTSYS if it was interrupted by a
605  * signal and 0 if @condition evaluated to true.
606  */
607 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
608         ((condition)                                                    \
609          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
610 
611 
612 #define __wait_event_killable(wq, condition)                            \
613         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
614 
615 /**
616  * wait_event_killable - sleep until a condition gets true
617  * @wq: the waitqueue to wait on
618  * @condition: a C expression for the event to wait for
619  *
620  * The process is put to sleep (TASK_KILLABLE) until the
621  * @condition evaluates to true or a signal is received.
622  * The @condition is checked each time the waitqueue @wq is woken up.
623  *
624  * wake_up() has to be called after changing any variable that could
625  * change the result of the wait condition.
626  *
627  * The function will return -ERESTARTSYS if it was interrupted by a
628  * signal and 0 if @condition evaluated to true.
629  */
630 #define wait_event_killable(wq, condition)                              \
631 ({                                                                      \
632         int __ret = 0;                                                  \
633         if (!(condition))                                               \
634                 __ret = __wait_event_killable(wq, condition);           \
635         __ret;                                                          \
636 })
637 
638 
639 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
640         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
641                             spin_unlock_irq(&lock);                     \
642                             cmd;                                        \
643                             schedule();                                 \
644                             spin_lock_irq(&lock))
645 
646 /**
647  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
648  *                           condition is checked under the lock. This
649  *                           is expected to be called with the lock
650  *                           taken.
651  * @wq: the waitqueue to wait on
652  * @condition: a C expression for the event to wait for
653  * @lock: a locked spinlock_t, which will be released before cmd
654  *        and schedule() and reacquired afterwards.
655  * @cmd: a command which is invoked outside the critical section before
656  *       sleep
657  *
658  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
659  * @condition evaluates to true. The @condition is checked each time
660  * the waitqueue @wq is woken up.
661  *
662  * wake_up() has to be called after changing any variable that could
663  * change the result of the wait condition.
664  *
665  * This is supposed to be called while holding the lock. The lock is
666  * dropped before invoking the cmd and going to sleep and is reacquired
667  * afterwards.
668  */
669 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
670 do {                                                                    \
671         if (condition)                                                  \
672                 break;                                                  \
673         __wait_event_lock_irq(wq, condition, lock, cmd);                \
674 } while (0)
675 
676 /**
677  * wait_event_lock_irq - sleep until a condition gets true. The
678  *                       condition is checked under the lock. This
679  *                       is expected to be called with the lock
680  *                       taken.
681  * @wq: the waitqueue to wait on
682  * @condition: a C expression for the event to wait for
683  * @lock: a locked spinlock_t, which will be released before schedule()
684  *        and reacquired afterwards.
685  *
686  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
687  * @condition evaluates to true. The @condition is checked each time
688  * the waitqueue @wq is woken up.
689  *
690  * wake_up() has to be called after changing any variable that could
691  * change the result of the wait condition.
692  *
693  * This is supposed to be called while holding the lock. The lock is
694  * dropped before going to sleep and is reacquired afterwards.
695  */
696 #define wait_event_lock_irq(wq, condition, lock)                        \
697 do {                                                                    \
698         if (condition)                                                  \
699                 break;                                                  \
700         __wait_event_lock_irq(wq, condition, lock, );                   \
701 } while (0)
702 
703 
704 #define __wait_event_interruptible_lock_irq(wq, condition, lock, cmd)   \
705         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
706                       spin_unlock_irq(&lock);                           \
707                       cmd;                                              \
708                       schedule();                                       \
709                       spin_lock_irq(&lock))
710 
711 /**
712  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
713  *              The condition is checked under the lock. This is expected to
714  *              be called with the lock taken.
715  * @wq: the waitqueue to wait on
716  * @condition: a C expression for the event to wait for
717  * @lock: a locked spinlock_t, which will be released before cmd and
718  *        schedule() and reacquired afterwards.
719  * @cmd: a command which is invoked outside the critical section before
720  *       sleep
721  *
722  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
723  * @condition evaluates to true or a signal is received. The @condition is
724  * checked each time the waitqueue @wq is woken up.
725  *
726  * wake_up() has to be called after changing any variable that could
727  * change the result of the wait condition.
728  *
729  * This is supposed to be called while holding the lock. The lock is
730  * dropped before invoking the cmd and going to sleep and is reacquired
731  * afterwards.
732  *
733  * The macro will return -ERESTARTSYS if it was interrupted by a signal
734  * and 0 if @condition evaluated to true.
735  */
736 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
737 ({                                                                      \
738         int __ret = 0;                                                  \
739         if (!(condition))                                               \
740                 __ret = __wait_event_interruptible_lock_irq(wq,         \
741                                                 condition, lock, cmd);  \
742         __ret;                                                          \
743 })
744 
745 /**
746  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
747  *              The condition is checked under the lock. This is expected
748  *              to be called with the lock taken.
749  * @wq: the waitqueue to wait on
750  * @condition: a C expression for the event to wait for
751  * @lock: a locked spinlock_t, which will be released before schedule()
752  *        and reacquired afterwards.
753  *
754  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
755  * @condition evaluates to true or signal is received. The @condition is
756  * checked each time the waitqueue @wq is woken up.
757  *
758  * wake_up() has to be called after changing any variable that could
759  * change the result of the wait condition.
760  *
761  * This is supposed to be called while holding the lock. The lock is
762  * dropped before going to sleep and is reacquired afterwards.
763  *
764  * The macro will return -ERESTARTSYS if it was interrupted by a signal
765  * and 0 if @condition evaluated to true.
766  */
767 #define wait_event_interruptible_lock_irq(wq, condition, lock)          \
768 ({                                                                      \
769         int __ret = 0;                                                  \
770         if (!(condition))                                               \
771                 __ret = __wait_event_interruptible_lock_irq(wq,         \
772                                                 condition, lock,);      \
773         __ret;                                                          \
774 })
775 
776 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
777                                                     lock, timeout)      \
778         ___wait_event(wq, ___wait_cond_timeout(condition),              \
779                       TASK_INTERRUPTIBLE, 0, timeout,                   \
780                       spin_unlock_irq(&lock);                           \
781                       __ret = schedule_timeout(__ret);                  \
782                       spin_lock_irq(&lock));
783 
784 /**
785  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
786  *              true or a timeout elapses. The condition is checked under
787  *              the lock. This is expected to be called with the lock taken.
788  * @wq: the waitqueue to wait on
789  * @condition: a C expression for the event to wait for
790  * @lock: a locked spinlock_t, which will be released before schedule()
791  *        and reacquired afterwards.
792  * @timeout: timeout, in jiffies
793  *
794  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
795  * @condition evaluates to true or signal is received. The @condition is
796  * checked each time the waitqueue @wq is woken up.
797  *
798  * wake_up() has to be called after changing any variable that could
799  * change the result of the wait condition.
800  *
801  * This is supposed to be called while holding the lock. The lock is
802  * dropped before going to sleep and is reacquired afterwards.
803  *
804  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
805  * was interrupted by a signal, and the remaining jiffies otherwise
806  * if the condition evaluated to true before the timeout elapsed.
807  */
808 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
809                                                   timeout)              \
810 ({                                                                      \
811         long __ret = timeout;                                           \
812         if (!___wait_cond_timeout(condition))                           \
813                 __ret = __wait_event_interruptible_lock_irq_timeout(    \
814                                         wq, condition, lock, timeout);  \
815         __ret;                                                          \
816 })
817 
818 /*
819  * Waitqueues which are removed from the waitqueue_head at wakeup time
820  */
821 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
822 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
823 long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state);
824 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
825 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key);
826 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
827 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
828 
829 #define DEFINE_WAIT_FUNC(name, function)                                \
830         wait_queue_t name = {                                           \
831                 .private        = current,                              \
832                 .func           = function,                             \
833                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
834         }
835 
836 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
837 
838 #define DEFINE_WAIT_BIT(name, word, bit)                                \
839         struct wait_bit_queue name = {                                  \
840                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
841                 .wait   = {                                             \
842                         .private        = current,                      \
843                         .func           = wake_bit_function,            \
844                         .task_list      =                               \
845                                 LIST_HEAD_INIT((name).wait.task_list),  \
846                 },                                                      \
847         }
848 
849 #define init_wait(wait)                                                 \
850         do {                                                            \
851                 (wait)->private = current;                              \
852                 (wait)->func = autoremove_wake_function;                \
853                 INIT_LIST_HEAD(&(wait)->task_list);                     \
854                 (wait)->flags = 0;                                      \
855         } while (0)
856 
857 /**
858  * wait_on_bit - wait for a bit to be cleared
859  * @word: the word being waited on, a kernel virtual address
860  * @bit: the bit of the word being waited on
861  * @action: the function used to sleep, which may take special actions
862  * @mode: the task state to sleep in
863  *
864  * There is a standard hashed waitqueue table for generic use. This
865  * is the part of the hashtable's accessor API that waits on a bit.
866  * For instance, if one were to have waiters on a bitflag, one would
867  * call wait_on_bit() in threads waiting for the bit to clear.
868  * One uses wait_on_bit() where one is waiting for the bit to clear,
869  * but has no intention of setting it.
870  */
871 static inline int
872 wait_on_bit(void *word, int bit, int (*action)(void *), unsigned mode)
873 {
874         if (!test_bit(bit, word))
875                 return 0;
876         return out_of_line_wait_on_bit(word, bit, action, mode);
877 }
878 
879 /**
880  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
881  * @word: the word being waited on, a kernel virtual address
882  * @bit: the bit of the word being waited on
883  * @action: the function used to sleep, which may take special actions
884  * @mode: the task state to sleep in
885  *
886  * There is a standard hashed waitqueue table for generic use. This
887  * is the part of the hashtable's accessor API that waits on a bit
888  * when one intends to set it, for instance, trying to lock bitflags.
889  * For instance, if one were to have waiters trying to set bitflag
890  * and waiting for it to clear before setting it, one would call
891  * wait_on_bit() in threads waiting to be able to set the bit.
892  * One uses wait_on_bit_lock() where one is waiting for the bit to
893  * clear with the intention of setting it, and when done, clearing it.
894  */
895 static inline int
896 wait_on_bit_lock(void *word, int bit, int (*action)(void *), unsigned mode)
897 {
898         if (!test_and_set_bit(bit, word))
899                 return 0;
900         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
901 }
902 
903 /**
904  * wait_on_atomic_t - Wait for an atomic_t to become 0
905  * @val: The atomic value being waited on, a kernel virtual address
906  * @action: the function used to sleep, which may take special actions
907  * @mode: the task state to sleep in
908  *
909  * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
910  * the purpose of getting a waitqueue, but we set the key to a bit number
911  * outside of the target 'word'.
912  */
913 static inline
914 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
915 {
916         if (atomic_read(val) == 0)
917                 return 0;
918         return out_of_line_wait_on_atomic_t(val, action, mode);
919 }
920 
921 #endif /* _LINUX_WAIT_H */
922 

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