Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/include/linux/wait.h

  1 #ifndef _LINUX_WAIT_H
  2 #define _LINUX_WAIT_H
  3 /*
  4  * Linux wait queue related types and methods
  5  */
  6 #include <linux/list.h>
  7 #include <linux/stddef.h>
  8 #include <linux/spinlock.h>
  9 #include <asm/current.h>
 10 #include <uapi/linux/wait.h>
 11 
 12 typedef struct __wait_queue wait_queue_t;
 13 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key);
 14 int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, void *key);
 15 
 16 struct __wait_queue {
 17         unsigned int            flags;
 18 #define WQ_FLAG_EXCLUSIVE       0x01
 19         void                    *private;
 20         wait_queue_func_t       func;
 21         struct list_head        task_list;
 22 };
 23 
 24 struct wait_bit_key {
 25         void                    *flags;
 26         int                     bit_nr;
 27 #define WAIT_ATOMIC_T_BIT_NR    -1
 28         unsigned long           timeout;
 29 };
 30 
 31 struct wait_bit_queue {
 32         struct wait_bit_key     key;
 33         wait_queue_t            wait;
 34 };
 35 
 36 struct __wait_queue_head {
 37         spinlock_t              lock;
 38         struct list_head        task_list;
 39 };
 40 typedef struct __wait_queue_head wait_queue_head_t;
 41 
 42 struct task_struct;
 43 
 44 /*
 45  * Macros for declaration and initialisaton of the datatypes
 46  */
 47 
 48 #define __WAITQUEUE_INITIALIZER(name, tsk) {                            \
 49         .private        = tsk,                                          \
 50         .func           = default_wake_function,                        \
 51         .task_list      = { NULL, NULL } }
 52 
 53 #define DECLARE_WAITQUEUE(name, tsk)                                    \
 54         wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
 55 
 56 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                           \
 57         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),              \
 58         .task_list      = { &(name).task_list, &(name).task_list } }
 59 
 60 #define DECLARE_WAIT_QUEUE_HEAD(name) \
 61         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
 62 
 63 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)                           \
 64         { .flags = word, .bit_nr = bit, }
 65 
 66 #define __WAIT_ATOMIC_T_KEY_INITIALIZER(p)                              \
 67         { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }
 68 
 69 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
 70 
 71 #define init_waitqueue_head(q)                          \
 72         do {                                            \
 73                 static struct lock_class_key __key;     \
 74                                                         \
 75                 __init_waitqueue_head((q), #q, &__key); \
 76         } while (0)
 77 
 78 #ifdef CONFIG_LOCKDEP
 79 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
 80         ({ init_waitqueue_head(&name); name; })
 81 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
 82         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
 83 #else
 84 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
 85 #endif
 86 
 87 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
 88 {
 89         q->flags        = 0;
 90         q->private      = p;
 91         q->func         = default_wake_function;
 92 }
 93 
 94 static inline void
 95 init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func)
 96 {
 97         q->flags        = 0;
 98         q->private      = NULL;
 99         q->func         = func;
100 }
101 
102 static inline int waitqueue_active(wait_queue_head_t *q)
103 {
104         return !list_empty(&q->task_list);
105 }
106 
107 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
108 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
109 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
110 
111 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
112 {
113         list_add(&new->task_list, &head->task_list);
114 }
115 
116 /*
117  * Used for wake-one threads:
118  */
119 static inline void
120 __add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
121 {
122         wait->flags |= WQ_FLAG_EXCLUSIVE;
123         __add_wait_queue(q, wait);
124 }
125 
126 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
127                                          wait_queue_t *new)
128 {
129         list_add_tail(&new->task_list, &head->task_list);
130 }
131 
132 static inline void
133 __add_wait_queue_tail_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
134 {
135         wait->flags |= WQ_FLAG_EXCLUSIVE;
136         __add_wait_queue_tail(q, wait);
137 }
138 
139 static inline void
140 __remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old)
141 {
142         list_del(&old->task_list);
143 }
144 
145 typedef int wait_bit_action_f(struct wait_bit_key *);
146 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
147 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
148 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
149 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
150 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
151 void __wake_up_bit(wait_queue_head_t *, void *, int);
152 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
153 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
154 void wake_up_bit(void *, int);
155 void wake_up_atomic_t(atomic_t *);
156 int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned);
157 int out_of_line_wait_on_bit_timeout(void *, int, wait_bit_action_f *, unsigned, unsigned long);
158 int out_of_line_wait_on_bit_lock(void *, int, wait_bit_action_f *, unsigned);
159 int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned);
160 wait_queue_head_t *bit_waitqueue(void *, int);
161 
162 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
163 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
164 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
165 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL, 1)
166 #define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)
167 
168 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
169 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
170 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
171 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
172 
173 /*
174  * Wakeup macros to be used to report events to the targets.
175  */
176 #define wake_up_poll(x, m)                                              \
177         __wake_up(x, TASK_NORMAL, 1, (void *) (m))
178 #define wake_up_locked_poll(x, m)                                       \
179         __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
180 #define wake_up_interruptible_poll(x, m)                                \
181         __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
182 #define wake_up_interruptible_sync_poll(x, m)                           \
183         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
184 
185 #define ___wait_cond_timeout(condition)                                 \
186 ({                                                                      \
187         bool __cond = (condition);                                      \
188         if (__cond && !__ret)                                           \
189                 __ret = 1;                                              \
190         __cond || !__ret;                                               \
191 })
192 
193 #define ___wait_is_interruptible(state)                                 \
194         (!__builtin_constant_p(state) ||                                \
195                 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE)  \
196 
197 /*
198  * The below macro ___wait_event() has an explicit shadow of the __ret
199  * variable when used from the wait_event_*() macros.
200  *
201  * This is so that both can use the ___wait_cond_timeout() construct
202  * to wrap the condition.
203  *
204  * The type inconsistency of the wait_event_*() __ret variable is also
205  * on purpose; we use long where we can return timeout values and int
206  * otherwise.
207  */
208 
209 #define ___wait_event(wq, condition, state, exclusive, ret, cmd)        \
210 ({                                                                      \
211         __label__ __out;                                                \
212         wait_queue_t __wait;                                            \
213         long __ret = ret;       /* explicit shadow */                   \
214                                                                         \
215         INIT_LIST_HEAD(&__wait.task_list);                              \
216         if (exclusive)                                                  \
217                 __wait.flags = WQ_FLAG_EXCLUSIVE;                       \
218         else                                                            \
219                 __wait.flags = 0;                                       \
220                                                                         \
221         for (;;) {                                                      \
222                 long __int = prepare_to_wait_event(&wq, &__wait, state);\
223                                                                         \
224                 if (condition)                                          \
225                         break;                                          \
226                                                                         \
227                 if (___wait_is_interruptible(state) && __int) {         \
228                         __ret = __int;                                  \
229                         if (exclusive) {                                \
230                                 abort_exclusive_wait(&wq, &__wait,      \
231                                                      state, NULL);      \
232                                 goto __out;                             \
233                         }                                               \
234                         break;                                          \
235                 }                                                       \
236                                                                         \
237                 cmd;                                                    \
238         }                                                               \
239         finish_wait(&wq, &__wait);                                      \
240 __out:  __ret;                                                          \
241 })
242 
243 #define __wait_event(wq, condition)                                     \
244         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
245                             schedule())
246 
247 /**
248  * wait_event - sleep until a condition gets true
249  * @wq: the waitqueue to wait on
250  * @condition: a C expression for the event to wait for
251  *
252  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
253  * @condition evaluates to true. The @condition is checked each time
254  * the waitqueue @wq is woken up.
255  *
256  * wake_up() has to be called after changing any variable that could
257  * change the result of the wait condition.
258  */
259 #define wait_event(wq, condition)                                       \
260 do {                                                                    \
261         if (condition)                                                  \
262                 break;                                                  \
263         __wait_event(wq, condition);                                    \
264 } while (0)
265 
266 #define __wait_event_timeout(wq, condition, timeout)                    \
267         ___wait_event(wq, ___wait_cond_timeout(condition),              \
268                       TASK_UNINTERRUPTIBLE, 0, timeout,                 \
269                       __ret = schedule_timeout(__ret))
270 
271 /**
272  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
273  * @wq: the waitqueue to wait on
274  * @condition: a C expression for the event to wait for
275  * @timeout: timeout, in jiffies
276  *
277  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
278  * @condition evaluates to true. The @condition is checked each time
279  * the waitqueue @wq is woken up.
280  *
281  * wake_up() has to be called after changing any variable that could
282  * change the result of the wait condition.
283  *
284  * Returns:
285  * 0 if the @condition evaluated to %false after the @timeout elapsed,
286  * 1 if the @condition evaluated to %true after the @timeout elapsed,
287  * or the remaining jiffies (at least 1) if the @condition evaluated
288  * to %true before the @timeout elapsed.
289  */
290 #define wait_event_timeout(wq, condition, timeout)                      \
291 ({                                                                      \
292         long __ret = timeout;                                           \
293         if (!___wait_cond_timeout(condition))                           \
294                 __ret = __wait_event_timeout(wq, condition, timeout);   \
295         __ret;                                                          \
296 })
297 
298 #define __wait_event_cmd(wq, condition, cmd1, cmd2)                     \
299         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
300                             cmd1; schedule(); cmd2)
301 
302 /**
303  * wait_event_cmd - sleep until a condition gets true
304  * @wq: the waitqueue to wait on
305  * @condition: a C expression for the event to wait for
306  * @cmd1: the command will be executed before sleep
307  * @cmd2: the command will be executed after sleep
308  *
309  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
310  * @condition evaluates to true. The @condition is checked each time
311  * the waitqueue @wq is woken up.
312  *
313  * wake_up() has to be called after changing any variable that could
314  * change the result of the wait condition.
315  */
316 #define wait_event_cmd(wq, condition, cmd1, cmd2)                       \
317 do {                                                                    \
318         if (condition)                                                  \
319                 break;                                                  \
320         __wait_event_cmd(wq, condition, cmd1, cmd2);                    \
321 } while (0)
322 
323 #define __wait_event_interruptible(wq, condition)                       \
324         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
325                       schedule())
326 
327 /**
328  * wait_event_interruptible - sleep until a condition gets true
329  * @wq: the waitqueue to wait on
330  * @condition: a C expression for the event to wait for
331  *
332  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
333  * @condition evaluates to true or a signal is received.
334  * The @condition is checked each time the waitqueue @wq is woken up.
335  *
336  * wake_up() has to be called after changing any variable that could
337  * change the result of the wait condition.
338  *
339  * The function will return -ERESTARTSYS if it was interrupted by a
340  * signal and 0 if @condition evaluated to true.
341  */
342 #define wait_event_interruptible(wq, condition)                         \
343 ({                                                                      \
344         int __ret = 0;                                                  \
345         if (!(condition))                                               \
346                 __ret = __wait_event_interruptible(wq, condition);      \
347         __ret;                                                          \
348 })
349 
350 #define __wait_event_interruptible_timeout(wq, condition, timeout)      \
351         ___wait_event(wq, ___wait_cond_timeout(condition),              \
352                       TASK_INTERRUPTIBLE, 0, timeout,                   \
353                       __ret = schedule_timeout(__ret))
354 
355 /**
356  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
357  * @wq: the waitqueue to wait on
358  * @condition: a C expression for the event to wait for
359  * @timeout: timeout, in jiffies
360  *
361  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
362  * @condition evaluates to true or a signal is received.
363  * The @condition is checked each time the waitqueue @wq is woken up.
364  *
365  * wake_up() has to be called after changing any variable that could
366  * change the result of the wait condition.
367  *
368  * Returns:
369  * 0 if the @condition evaluated to %false after the @timeout elapsed,
370  * 1 if the @condition evaluated to %true after the @timeout elapsed,
371  * the remaining jiffies (at least 1) if the @condition evaluated
372  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
373  * interrupted by a signal.
374  */
375 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
376 ({                                                                      \
377         long __ret = timeout;                                           \
378         if (!___wait_cond_timeout(condition))                           \
379                 __ret = __wait_event_interruptible_timeout(wq,          \
380                                                 condition, timeout);    \
381         __ret;                                                          \
382 })
383 
384 #define __wait_event_hrtimeout(wq, condition, timeout, state)           \
385 ({                                                                      \
386         int __ret = 0;                                                  \
387         struct hrtimer_sleeper __t;                                     \
388                                                                         \
389         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
390                               HRTIMER_MODE_REL);                        \
391         hrtimer_init_sleeper(&__t, current);                            \
392         if ((timeout).tv64 != KTIME_MAX)                                \
393                 hrtimer_start_range_ns(&__t.timer, timeout,             \
394                                        current->timer_slack_ns,         \
395                                        HRTIMER_MODE_REL);               \
396                                                                         \
397         __ret = ___wait_event(wq, condition, state, 0, 0,               \
398                 if (!__t.task) {                                        \
399                         __ret = -ETIME;                                 \
400                         break;                                          \
401                 }                                                       \
402                 schedule());                                            \
403                                                                         \
404         hrtimer_cancel(&__t.timer);                                     \
405         destroy_hrtimer_on_stack(&__t.timer);                           \
406         __ret;                                                          \
407 })
408 
409 /**
410  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
411  * @wq: the waitqueue to wait on
412  * @condition: a C expression for the event to wait for
413  * @timeout: timeout, as a ktime_t
414  *
415  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
416  * @condition evaluates to true or a signal is received.
417  * The @condition is checked each time the waitqueue @wq is woken up.
418  *
419  * wake_up() has to be called after changing any variable that could
420  * change the result of the wait condition.
421  *
422  * The function returns 0 if @condition became true, or -ETIME if the timeout
423  * elapsed.
424  */
425 #define wait_event_hrtimeout(wq, condition, timeout)                    \
426 ({                                                                      \
427         int __ret = 0;                                                  \
428         if (!(condition))                                               \
429                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
430                                                TASK_UNINTERRUPTIBLE);   \
431         __ret;                                                          \
432 })
433 
434 /**
435  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
436  * @wq: the waitqueue to wait on
437  * @condition: a C expression for the event to wait for
438  * @timeout: timeout, as a ktime_t
439  *
440  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
441  * @condition evaluates to true or a signal is received.
442  * The @condition is checked each time the waitqueue @wq is woken up.
443  *
444  * wake_up() has to be called after changing any variable that could
445  * change the result of the wait condition.
446  *
447  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
448  * interrupted by a signal, or -ETIME if the timeout elapsed.
449  */
450 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
451 ({                                                                      \
452         long __ret = 0;                                                 \
453         if (!(condition))                                               \
454                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
455                                                TASK_INTERRUPTIBLE);     \
456         __ret;                                                          \
457 })
458 
459 #define __wait_event_interruptible_exclusive(wq, condition)             \
460         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
461                       schedule())
462 
463 #define wait_event_interruptible_exclusive(wq, condition)               \
464 ({                                                                      \
465         int __ret = 0;                                                  \
466         if (!(condition))                                               \
467                 __ret = __wait_event_interruptible_exclusive(wq, condition);\
468         __ret;                                                          \
469 })
470 
471 
472 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
473 ({                                                                      \
474         int __ret = 0;                                                  \
475         DEFINE_WAIT(__wait);                                            \
476         if (exclusive)                                                  \
477                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
478         do {                                                            \
479                 if (likely(list_empty(&__wait.task_list)))              \
480                         __add_wait_queue_tail(&(wq), &__wait);          \
481                 set_current_state(TASK_INTERRUPTIBLE);                  \
482                 if (signal_pending(current)) {                          \
483                         __ret = -ERESTARTSYS;                           \
484                         break;                                          \
485                 }                                                       \
486                 if (irq)                                                \
487                         spin_unlock_irq(&(wq).lock);                    \
488                 else                                                    \
489                         spin_unlock(&(wq).lock);                        \
490                 schedule();                                             \
491                 if (irq)                                                \
492                         spin_lock_irq(&(wq).lock);                      \
493                 else                                                    \
494                         spin_lock(&(wq).lock);                          \
495         } while (!(condition));                                         \
496         __remove_wait_queue(&(wq), &__wait);                            \
497         __set_current_state(TASK_RUNNING);                              \
498         __ret;                                                          \
499 })
500 
501 
502 /**
503  * wait_event_interruptible_locked - sleep until a condition gets true
504  * @wq: the waitqueue to wait on
505  * @condition: a C expression for the event to wait for
506  *
507  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
508  * @condition evaluates to true or a signal is received.
509  * The @condition is checked each time the waitqueue @wq is woken up.
510  *
511  * It must be called with wq.lock being held.  This spinlock is
512  * unlocked while sleeping but @condition testing is done while lock
513  * is held and when this macro exits the lock is held.
514  *
515  * The lock is locked/unlocked using spin_lock()/spin_unlock()
516  * functions which must match the way they are locked/unlocked outside
517  * of this macro.
518  *
519  * wake_up_locked() has to be called after changing any variable that could
520  * change the result of the wait condition.
521  *
522  * The function will return -ERESTARTSYS if it was interrupted by a
523  * signal and 0 if @condition evaluated to true.
524  */
525 #define wait_event_interruptible_locked(wq, condition)                  \
526         ((condition)                                                    \
527          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
528 
529 /**
530  * wait_event_interruptible_locked_irq - sleep until a condition gets true
531  * @wq: the waitqueue to wait on
532  * @condition: a C expression for the event to wait for
533  *
534  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
535  * @condition evaluates to true or a signal is received.
536  * The @condition is checked each time the waitqueue @wq is woken up.
537  *
538  * It must be called with wq.lock being held.  This spinlock is
539  * unlocked while sleeping but @condition testing is done while lock
540  * is held and when this macro exits the lock is held.
541  *
542  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
543  * functions which must match the way they are locked/unlocked outside
544  * of this macro.
545  *
546  * wake_up_locked() has to be called after changing any variable that could
547  * change the result of the wait condition.
548  *
549  * The function will return -ERESTARTSYS if it was interrupted by a
550  * signal and 0 if @condition evaluated to true.
551  */
552 #define wait_event_interruptible_locked_irq(wq, condition)              \
553         ((condition)                                                    \
554          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
555 
556 /**
557  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
558  * @wq: the waitqueue to wait on
559  * @condition: a C expression for the event to wait for
560  *
561  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
562  * @condition evaluates to true or a signal is received.
563  * The @condition is checked each time the waitqueue @wq is woken up.
564  *
565  * It must be called with wq.lock being held.  This spinlock is
566  * unlocked while sleeping but @condition testing is done while lock
567  * is held and when this macro exits the lock is held.
568  *
569  * The lock is locked/unlocked using spin_lock()/spin_unlock()
570  * functions which must match the way they are locked/unlocked outside
571  * of this macro.
572  *
573  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
574  * set thus when other process waits process on the list if this
575  * process is awaken further processes are not considered.
576  *
577  * wake_up_locked() has to be called after changing any variable that could
578  * change the result of the wait condition.
579  *
580  * The function will return -ERESTARTSYS if it was interrupted by a
581  * signal and 0 if @condition evaluated to true.
582  */
583 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
584         ((condition)                                                    \
585          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
586 
587 /**
588  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
589  * @wq: the waitqueue to wait on
590  * @condition: a C expression for the event to wait for
591  *
592  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
593  * @condition evaluates to true or a signal is received.
594  * The @condition is checked each time the waitqueue @wq is woken up.
595  *
596  * It must be called with wq.lock being held.  This spinlock is
597  * unlocked while sleeping but @condition testing is done while lock
598  * is held and when this macro exits the lock is held.
599  *
600  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
601  * functions which must match the way they are locked/unlocked outside
602  * of this macro.
603  *
604  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
605  * set thus when other process waits process on the list if this
606  * process is awaken further processes are not considered.
607  *
608  * wake_up_locked() has to be called after changing any variable that could
609  * change the result of the wait condition.
610  *
611  * The function will return -ERESTARTSYS if it was interrupted by a
612  * signal and 0 if @condition evaluated to true.
613  */
614 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
615         ((condition)                                                    \
616          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
617 
618 
619 #define __wait_event_killable(wq, condition)                            \
620         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
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                 __ret = __wait_event_killable(wq, condition);           \
642         __ret;                                                          \
643 })
644 
645 
646 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
647         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
648                             spin_unlock_irq(&lock);                     \
649                             cmd;                                        \
650                             schedule();                                 \
651                             spin_lock_irq(&lock))
652 
653 /**
654  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
655  *                           condition is checked under the lock. This
656  *                           is expected to be called with the lock
657  *                           taken.
658  * @wq: the waitqueue to wait on
659  * @condition: a C expression for the event to wait for
660  * @lock: a locked spinlock_t, which will be released before cmd
661  *        and schedule() and reacquired afterwards.
662  * @cmd: a command which is invoked outside the critical section before
663  *       sleep
664  *
665  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
666  * @condition evaluates to true. The @condition is checked each time
667  * the waitqueue @wq is woken up.
668  *
669  * wake_up() has to be called after changing any variable that could
670  * change the result of the wait condition.
671  *
672  * This is supposed to be called while holding the lock. The lock is
673  * dropped before invoking the cmd and going to sleep and is reacquired
674  * afterwards.
675  */
676 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
677 do {                                                                    \
678         if (condition)                                                  \
679                 break;                                                  \
680         __wait_event_lock_irq(wq, condition, lock, cmd);                \
681 } while (0)
682 
683 /**
684  * wait_event_lock_irq - sleep until a condition gets true. The
685  *                       condition is checked under the lock. This
686  *                       is expected to be called with the lock
687  *                       taken.
688  * @wq: the waitqueue to wait on
689  * @condition: a C expression for the event to wait for
690  * @lock: a locked spinlock_t, which will be released before schedule()
691  *        and reacquired afterwards.
692  *
693  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
694  * @condition evaluates to true. The @condition is checked each time
695  * the waitqueue @wq is woken up.
696  *
697  * wake_up() has to be called after changing any variable that could
698  * change the result of the wait condition.
699  *
700  * This is supposed to be called while holding the lock. The lock is
701  * dropped before going to sleep and is reacquired afterwards.
702  */
703 #define wait_event_lock_irq(wq, condition, lock)                        \
704 do {                                                                    \
705         if (condition)                                                  \
706                 break;                                                  \
707         __wait_event_lock_irq(wq, condition, lock, );                   \
708 } while (0)
709 
710 
711 #define __wait_event_interruptible_lock_irq(wq, condition, lock, cmd)   \
712         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
713                       spin_unlock_irq(&lock);                           \
714                       cmd;                                              \
715                       schedule();                                       \
716                       spin_lock_irq(&lock))
717 
718 /**
719  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
720  *              The condition is checked under the lock. This is expected to
721  *              be called with the lock taken.
722  * @wq: the waitqueue to wait on
723  * @condition: a C expression for the event to wait for
724  * @lock: a locked spinlock_t, which will be released before cmd and
725  *        schedule() and reacquired afterwards.
726  * @cmd: a command which is invoked outside the critical section before
727  *       sleep
728  *
729  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
730  * @condition evaluates to true or a signal is received. The @condition is
731  * checked each time the waitqueue @wq is woken up.
732  *
733  * wake_up() has to be called after changing any variable that could
734  * change the result of the wait condition.
735  *
736  * This is supposed to be called while holding the lock. The lock is
737  * dropped before invoking the cmd and going to sleep and is reacquired
738  * afterwards.
739  *
740  * The macro will return -ERESTARTSYS if it was interrupted by a signal
741  * and 0 if @condition evaluated to true.
742  */
743 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
744 ({                                                                      \
745         int __ret = 0;                                                  \
746         if (!(condition))                                               \
747                 __ret = __wait_event_interruptible_lock_irq(wq,         \
748                                                 condition, lock, cmd);  \
749         __ret;                                                          \
750 })
751 
752 /**
753  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
754  *              The condition is checked under the lock. This is expected
755  *              to be called with the lock taken.
756  * @wq: the waitqueue to wait on
757  * @condition: a C expression for the event to wait for
758  * @lock: a locked spinlock_t, which will be released before schedule()
759  *        and reacquired afterwards.
760  *
761  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
762  * @condition evaluates to true or signal is received. The @condition is
763  * checked each time the waitqueue @wq is woken up.
764  *
765  * wake_up() has to be called after changing any variable that could
766  * change the result of the wait condition.
767  *
768  * This is supposed to be called while holding the lock. The lock is
769  * dropped before going to sleep and is reacquired afterwards.
770  *
771  * The macro will return -ERESTARTSYS if it was interrupted by a signal
772  * and 0 if @condition evaluated to true.
773  */
774 #define wait_event_interruptible_lock_irq(wq, condition, lock)          \
775 ({                                                                      \
776         int __ret = 0;                                                  \
777         if (!(condition))                                               \
778                 __ret = __wait_event_interruptible_lock_irq(wq,         \
779                                                 condition, lock,);      \
780         __ret;                                                          \
781 })
782 
783 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
784                                                     lock, timeout)      \
785         ___wait_event(wq, ___wait_cond_timeout(condition),              \
786                       TASK_INTERRUPTIBLE, 0, timeout,                   \
787                       spin_unlock_irq(&lock);                           \
788                       __ret = schedule_timeout(__ret);                  \
789                       spin_lock_irq(&lock));
790 
791 /**
792  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
793  *              true or a timeout elapses. The condition is checked under
794  *              the lock. This is expected to be called with the lock taken.
795  * @wq: the waitqueue to wait on
796  * @condition: a C expression for the event to wait for
797  * @lock: a locked spinlock_t, which will be released before schedule()
798  *        and reacquired afterwards.
799  * @timeout: timeout, in jiffies
800  *
801  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
802  * @condition evaluates to true or signal is received. The @condition is
803  * checked each time the waitqueue @wq is woken up.
804  *
805  * wake_up() has to be called after changing any variable that could
806  * change the result of the wait condition.
807  *
808  * This is supposed to be called while holding the lock. The lock is
809  * dropped before going to sleep and is reacquired afterwards.
810  *
811  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
812  * was interrupted by a signal, and the remaining jiffies otherwise
813  * if the condition evaluated to true before the timeout elapsed.
814  */
815 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
816                                                   timeout)              \
817 ({                                                                      \
818         long __ret = timeout;                                           \
819         if (!___wait_cond_timeout(condition))                           \
820                 __ret = __wait_event_interruptible_lock_irq_timeout(    \
821                                         wq, condition, lock, timeout);  \
822         __ret;                                                          \
823 })
824 
825 /*
826  * Waitqueues which are removed from the waitqueue_head at wakeup time
827  */
828 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
829 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
830 long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state);
831 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
832 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key);
833 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
834 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
835 
836 #define DEFINE_WAIT_FUNC(name, function)                                \
837         wait_queue_t name = {                                           \
838                 .private        = current,                              \
839                 .func           = function,                             \
840                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
841         }
842 
843 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
844 
845 #define DEFINE_WAIT_BIT(name, word, bit)                                \
846         struct wait_bit_queue name = {                                  \
847                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
848                 .wait   = {                                             \
849                         .private        = current,                      \
850                         .func           = wake_bit_function,            \
851                         .task_list      =                               \
852                                 LIST_HEAD_INIT((name).wait.task_list),  \
853                 },                                                      \
854         }
855 
856 #define init_wait(wait)                                                 \
857         do {                                                            \
858                 (wait)->private = current;                              \
859                 (wait)->func = autoremove_wake_function;                \
860                 INIT_LIST_HEAD(&(wait)->task_list);                     \
861                 (wait)->flags = 0;                                      \
862         } while (0)
863 
864 
865 extern int bit_wait(struct wait_bit_key *);
866 extern int bit_wait_io(struct wait_bit_key *);
867 extern int bit_wait_timeout(struct wait_bit_key *);
868 extern int bit_wait_io_timeout(struct wait_bit_key *);
869 
870 /**
871  * wait_on_bit - wait for a bit to be cleared
872  * @word: the word being waited on, a kernel virtual address
873  * @bit: the bit of the word being waited on
874  * @mode: the task state to sleep in
875  *
876  * There is a standard hashed waitqueue table for generic use. This
877  * is the part of the hashtable's accessor API that waits on a bit.
878  * For instance, if one were to have waiters on a bitflag, one would
879  * call wait_on_bit() in threads waiting for the bit to clear.
880  * One uses wait_on_bit() where one is waiting for the bit to clear,
881  * but has no intention of setting it.
882  * Returned value will be zero if the bit was cleared, or non-zero
883  * if the process received a signal and the mode permitted wakeup
884  * on that signal.
885  */
886 static inline int
887 wait_on_bit(void *word, int bit, unsigned mode)
888 {
889         if (!test_bit(bit, word))
890                 return 0;
891         return out_of_line_wait_on_bit(word, bit,
892                                        bit_wait,
893                                        mode);
894 }
895 
896 /**
897  * wait_on_bit_io - wait for a bit to be cleared
898  * @word: the word being waited on, a kernel virtual address
899  * @bit: the bit of the word being waited on
900  * @mode: the task state to sleep in
901  *
902  * Use the standard hashed waitqueue table to wait for a bit
903  * to be cleared.  This is similar to wait_on_bit(), but calls
904  * io_schedule() instead of schedule() for the actual waiting.
905  *
906  * Returned value will be zero if the bit was cleared, or non-zero
907  * if the process received a signal and the mode permitted wakeup
908  * on that signal.
909  */
910 static inline int
911 wait_on_bit_io(void *word, int bit, unsigned mode)
912 {
913         if (!test_bit(bit, word))
914                 return 0;
915         return out_of_line_wait_on_bit(word, bit,
916                                        bit_wait_io,
917                                        mode);
918 }
919 
920 /**
921  * wait_on_bit_action - wait for a bit to be cleared
922  * @word: the word being waited on, a kernel virtual address
923  * @bit: the bit of the word being waited on
924  * @action: the function used to sleep, which may take special actions
925  * @mode: the task state to sleep in
926  *
927  * Use the standard hashed waitqueue table to wait for a bit
928  * to be cleared, and allow the waiting action to be specified.
929  * This is like wait_on_bit() but allows fine control of how the waiting
930  * is done.
931  *
932  * Returned value will be zero if the bit was cleared, or non-zero
933  * if the process received a signal and the mode permitted wakeup
934  * on that signal.
935  */
936 static inline int
937 wait_on_bit_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
938 {
939         if (!test_bit(bit, word))
940                 return 0;
941         return out_of_line_wait_on_bit(word, bit, action, mode);
942 }
943 
944 /**
945  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
946  * @word: the word being waited on, a kernel virtual address
947  * @bit: the bit of the word being waited on
948  * @mode: the task state to sleep in
949  *
950  * There is a standard hashed waitqueue table for generic use. This
951  * is the part of the hashtable's accessor API that waits on a bit
952  * when one intends to set it, for instance, trying to lock bitflags.
953  * For instance, if one were to have waiters trying to set bitflag
954  * and waiting for it to clear before setting it, one would call
955  * wait_on_bit() in threads waiting to be able to set the bit.
956  * One uses wait_on_bit_lock() where one is waiting for the bit to
957  * clear with the intention of setting it, and when done, clearing it.
958  *
959  * Returns zero if the bit was (eventually) found to be clear and was
960  * set.  Returns non-zero if a signal was delivered to the process and
961  * the @mode allows that signal to wake the process.
962  */
963 static inline int
964 wait_on_bit_lock(void *word, int bit, unsigned mode)
965 {
966         if (!test_and_set_bit(bit, word))
967                 return 0;
968         return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode);
969 }
970 
971 /**
972  * wait_on_bit_lock_io - wait for a bit to be cleared, when wanting to set it
973  * @word: the word being waited on, a kernel virtual address
974  * @bit: the bit of the word being waited on
975  * @mode: the task state to sleep in
976  *
977  * Use the standard hashed waitqueue table to wait for a bit
978  * to be cleared and then to atomically set it.  This is similar
979  * to wait_on_bit(), but calls io_schedule() instead of schedule()
980  * for the actual waiting.
981  *
982  * Returns zero if the bit was (eventually) found to be clear and was
983  * set.  Returns non-zero if a signal was delivered to the process and
984  * the @mode allows that signal to wake the process.
985  */
986 static inline int
987 wait_on_bit_lock_io(void *word, int bit, unsigned mode)
988 {
989         if (!test_and_set_bit(bit, word))
990                 return 0;
991         return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode);
992 }
993 
994 /**
995  * wait_on_bit_lock_action - wait for a bit to be cleared, when wanting to set it
996  * @word: the word being waited on, a kernel virtual address
997  * @bit: the bit of the word being waited on
998  * @action: the function used to sleep, which may take special actions
999  * @mode: the task state to sleep in
1000  *
1001  * Use the standard hashed waitqueue table to wait for a bit
1002  * to be cleared and then to set it, and allow the waiting action
1003  * to be specified.
1004  * This is like wait_on_bit() but allows fine control of how the waiting
1005  * is done.
1006  *
1007  * Returns zero if the bit was (eventually) found to be clear and was
1008  * set.  Returns non-zero if a signal was delivered to the process and
1009  * the @mode allows that signal to wake the process.
1010  */
1011 static inline int
1012 wait_on_bit_lock_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
1013 {
1014         if (!test_and_set_bit(bit, word))
1015                 return 0;
1016         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
1017 }
1018 
1019 /**
1020  * wait_on_atomic_t - Wait for an atomic_t to become 0
1021  * @val: The atomic value being waited on, a kernel virtual address
1022  * @action: the function used to sleep, which may take special actions
1023  * @mode: the task state to sleep in
1024  *
1025  * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
1026  * the purpose of getting a waitqueue, but we set the key to a bit number
1027  * outside of the target 'word'.
1028  */
1029 static inline
1030 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
1031 {
1032         if (atomic_read(val) == 0)
1033                 return 0;
1034         return out_of_line_wait_on_atomic_t(val, action, mode);
1035 }
1036 
1037 #endif /* _LINUX_WAIT_H */
1038 

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