Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6.git] / include / linux / wait.h
1 #ifndef _LINUX_WAIT_H
2 #define _LINUX_WAIT_H
3
4 #define WNOHANG         0x00000001
5 #define WUNTRACED       0x00000002
6 #define WSTOPPED        WUNTRACED
7 #define WEXITED         0x00000004
8 #define WCONTINUED      0x00000008
9 #define WNOWAIT         0x01000000      /* Don't reap, just poll status.  */
10
11 #define __WNOTHREAD     0x20000000      /* Don't wait on children of other threads in this group */
12 #define __WALL          0x40000000      /* Wait on all children, regardless of type */
13 #define __WCLONE        0x80000000      /* Wait only on non-SIGCHLD children */
14
15 /* First argument to waitid: */
16 #define P_ALL           0
17 #define P_PID           1
18 #define P_PGID          2
19
20 #ifdef __KERNEL__
21
22 #include <linux/list.h>
23 #include <linux/stddef.h>
24 #include <linux/spinlock.h>
25 #include <asm/system.h>
26 #include <asm/current.h>
27
28 typedef struct __wait_queue wait_queue_t;
29 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int sync, void *key);
30 int default_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
31
32 struct __wait_queue {
33         unsigned int flags;
34 #define WQ_FLAG_EXCLUSIVE       0x01
35         void *private;
36         wait_queue_func_t func;
37         struct list_head task_list;
38 };
39
40 struct wait_bit_key {
41         void *flags;
42         int bit_nr;
43 };
44
45 struct wait_bit_queue {
46         struct wait_bit_key key;
47         wait_queue_t wait;
48 };
49
50 struct __wait_queue_head {
51         spinlock_t lock;
52         struct list_head task_list;
53 };
54 typedef struct __wait_queue_head wait_queue_head_t;
55
56 struct task_struct;
57
58 /*
59  * Macros for declaration and initialisaton of the datatypes
60  */
61
62 #define __WAITQUEUE_INITIALIZER(name, tsk) {                            \
63         .private        = tsk,                                          \
64         .func           = default_wake_function,                        \
65         .task_list      = { NULL, NULL } }
66
67 #define DECLARE_WAITQUEUE(name, tsk)                                    \
68         wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
69
70 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                           \
71         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),              \
72         .task_list      = { &(name).task_list, &(name).task_list } }
73
74 #define DECLARE_WAIT_QUEUE_HEAD(name) \
75         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
76
77 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)                           \
78         { .flags = word, .bit_nr = bit, }
79
80 extern void init_waitqueue_head(wait_queue_head_t *q);
81
82 #ifdef CONFIG_LOCKDEP
83 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
84         ({ init_waitqueue_head(&name); name; })
85 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
86         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
87 #else
88 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
89 #endif
90
91 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
92 {
93         q->flags = 0;
94         q->private = p;
95         q->func = default_wake_function;
96 }
97
98 static inline void init_waitqueue_func_entry(wait_queue_t *q,
99                                         wait_queue_func_t func)
100 {
101         q->flags = 0;
102         q->private = NULL;
103         q->func = func;
104 }
105
106 static inline int waitqueue_active(wait_queue_head_t *q)
107 {
108         return !list_empty(&q->task_list);
109 }
110
111 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
112 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
113 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
114
115 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
116 {
117         list_add(&new->task_list, &head->task_list);
118 }
119
120 /*
121  * Used for wake-one threads:
122  */
123 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
124                                                 wait_queue_t *new)
125 {
126         list_add_tail(&new->task_list, &head->task_list);
127 }
128
129 static inline void __remove_wait_queue(wait_queue_head_t *head,
130                                                         wait_queue_t *old)
131 {
132         list_del(&old->task_list);
133 }
134
135 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
136 extern void __wake_up_locked(wait_queue_head_t *q, unsigned int mode);
137 extern void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
138 void __wake_up_bit(wait_queue_head_t *, void *, int);
139 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
140 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
141 void wake_up_bit(void *, int);
142 int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned);
143 int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned);
144 wait_queue_head_t *bit_waitqueue(void *, int);
145
146 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
147 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
148 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
149 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL)
150
151 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
152 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
153 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
154 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
155
156 #ifdef CONFIG_DEBUG_LOCK_ALLOC
157 /*
158  * macro to avoid include hell
159  */
160 #define wake_up_nested(x, s)                                            \
161 do {                                                                    \
162         unsigned long flags;                                            \
163                                                                         \
164         spin_lock_irqsave_nested(&(x)->lock, flags, (s));               \
165         wake_up_locked(x);                                              \
166         spin_unlock_irqrestore(&(x)->lock, flags);                      \
167 } while (0)
168 #else
169 #define wake_up_nested(x, s)            wake_up(x)
170 #endif
171
172 #define __wait_event(wq, condition)                                     \
173 do {                                                                    \
174         DEFINE_WAIT(__wait);                                            \
175                                                                         \
176         for (;;) {                                                      \
177                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
178                 if (condition)                                          \
179                         break;                                          \
180                 schedule();                                             \
181         }                                                               \
182         finish_wait(&wq, &__wait);                                      \
183 } while (0)
184
185 /**
186  * wait_event - sleep until a condition gets true
187  * @wq: the waitqueue to wait on
188  * @condition: a C expression for the event to wait for
189  *
190  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
191  * @condition evaluates to true. The @condition is checked each time
192  * the waitqueue @wq is woken up.
193  *
194  * wake_up() has to be called after changing any variable that could
195  * change the result of the wait condition.
196  */
197 #define wait_event(wq, condition)                                       \
198 do {                                                                    \
199         if (condition)                                                  \
200                 break;                                                  \
201         __wait_event(wq, condition);                                    \
202 } while (0)
203
204 #define __wait_event_timeout(wq, condition, ret)                        \
205 do {                                                                    \
206         DEFINE_WAIT(__wait);                                            \
207                                                                         \
208         for (;;) {                                                      \
209                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
210                 if (condition)                                          \
211                         break;                                          \
212                 ret = schedule_timeout(ret);                            \
213                 if (!ret)                                               \
214                         break;                                          \
215         }                                                               \
216         finish_wait(&wq, &__wait);                                      \
217 } while (0)
218
219 /**
220  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
221  * @wq: the waitqueue to wait on
222  * @condition: a C expression for the event to wait for
223  * @timeout: timeout, in jiffies
224  *
225  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
226  * @condition evaluates to true. The @condition is checked each time
227  * the waitqueue @wq is woken up.
228  *
229  * wake_up() has to be called after changing any variable that could
230  * change the result of the wait condition.
231  *
232  * The function returns 0 if the @timeout elapsed, and the remaining
233  * jiffies if the condition evaluated to true before the timeout elapsed.
234  */
235 #define wait_event_timeout(wq, condition, timeout)                      \
236 ({                                                                      \
237         long __ret = timeout;                                           \
238         if (!(condition))                                               \
239                 __wait_event_timeout(wq, condition, __ret);             \
240         __ret;                                                          \
241 })
242
243 #define __wait_event_interruptible(wq, condition, ret)                  \
244 do {                                                                    \
245         DEFINE_WAIT(__wait);                                            \
246                                                                         \
247         for (;;) {                                                      \
248                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
249                 if (condition)                                          \
250                         break;                                          \
251                 if (!signal_pending(current)) {                         \
252                         schedule();                                     \
253                         continue;                                       \
254                 }                                                       \
255                 ret = -ERESTARTSYS;                                     \
256                 break;                                                  \
257         }                                                               \
258         finish_wait(&wq, &__wait);                                      \
259 } while (0)
260
261 /**
262  * wait_event_interruptible - sleep until a condition gets true
263  * @wq: the waitqueue to wait on
264  * @condition: a C expression for the event to wait for
265  *
266  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
267  * @condition evaluates to true or a signal is received.
268  * The @condition is checked each time the waitqueue @wq is woken up.
269  *
270  * wake_up() has to be called after changing any variable that could
271  * change the result of the wait condition.
272  *
273  * The function will return -ERESTARTSYS if it was interrupted by a
274  * signal and 0 if @condition evaluated to true.
275  */
276 #define wait_event_interruptible(wq, condition)                         \
277 ({                                                                      \
278         int __ret = 0;                                                  \
279         if (!(condition))                                               \
280                 __wait_event_interruptible(wq, condition, __ret);       \
281         __ret;                                                          \
282 })
283
284 #define __wait_event_interruptible_timeout(wq, condition, ret)          \
285 do {                                                                    \
286         DEFINE_WAIT(__wait);                                            \
287                                                                         \
288         for (;;) {                                                      \
289                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
290                 if (condition)                                          \
291                         break;                                          \
292                 if (!signal_pending(current)) {                         \
293                         ret = schedule_timeout(ret);                    \
294                         if (!ret)                                       \
295                                 break;                                  \
296                         continue;                                       \
297                 }                                                       \
298                 ret = -ERESTARTSYS;                                     \
299                 break;                                                  \
300         }                                                               \
301         finish_wait(&wq, &__wait);                                      \
302 } while (0)
303
304 /**
305  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
306  * @wq: the waitqueue to wait on
307  * @condition: a C expression for the event to wait for
308  * @timeout: timeout, in jiffies
309  *
310  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
311  * @condition evaluates to true or a signal is received.
312  * The @condition is checked each time the waitqueue @wq is woken up.
313  *
314  * wake_up() has to be called after changing any variable that could
315  * change the result of the wait condition.
316  *
317  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
318  * was interrupted by a signal, and the remaining jiffies otherwise
319  * if the condition evaluated to true before the timeout elapsed.
320  */
321 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
322 ({                                                                      \
323         long __ret = timeout;                                           \
324         if (!(condition))                                               \
325                 __wait_event_interruptible_timeout(wq, condition, __ret); \
326         __ret;                                                          \
327 })
328
329 #define __wait_event_interruptible_exclusive(wq, condition, ret)        \
330 do {                                                                    \
331         DEFINE_WAIT(__wait);                                            \
332                                                                         \
333         for (;;) {                                                      \
334                 prepare_to_wait_exclusive(&wq, &__wait,                 \
335                                         TASK_INTERRUPTIBLE);            \
336                 if (condition)                                          \
337                         break;                                          \
338                 if (!signal_pending(current)) {                         \
339                         schedule();                                     \
340                         continue;                                       \
341                 }                                                       \
342                 ret = -ERESTARTSYS;                                     \
343                 break;                                                  \
344         }                                                               \
345         finish_wait(&wq, &__wait);                                      \
346 } while (0)
347
348 #define wait_event_interruptible_exclusive(wq, condition)               \
349 ({                                                                      \
350         int __ret = 0;                                                  \
351         if (!(condition))                                               \
352                 __wait_event_interruptible_exclusive(wq, condition, __ret);\
353         __ret;                                                          \
354 })
355
356 #define __wait_event_killable(wq, condition, ret)                       \
357 do {                                                                    \
358         DEFINE_WAIT(__wait);                                            \
359                                                                         \
360         for (;;) {                                                      \
361                 prepare_to_wait(&wq, &__wait, TASK_KILLABLE);           \
362                 if (condition)                                          \
363                         break;                                          \
364                 if (!fatal_signal_pending(current)) {                   \
365                         schedule();                                     \
366                         continue;                                       \
367                 }                                                       \
368                 ret = -ERESTARTSYS;                                     \
369                 break;                                                  \
370         }                                                               \
371         finish_wait(&wq, &__wait);                                      \
372 } while (0)
373
374 /**
375  * wait_event_killable - sleep until a condition gets true
376  * @wq: the waitqueue to wait on
377  * @condition: a C expression for the event to wait for
378  *
379  * The process is put to sleep (TASK_KILLABLE) until the
380  * @condition evaluates to true or a signal is received.
381  * The @condition is checked each time the waitqueue @wq is woken up.
382  *
383  * wake_up() has to be called after changing any variable that could
384  * change the result of the wait condition.
385  *
386  * The function will return -ERESTARTSYS if it was interrupted by a
387  * signal and 0 if @condition evaluated to true.
388  */
389 #define wait_event_killable(wq, condition)                              \
390 ({                                                                      \
391         int __ret = 0;                                                  \
392         if (!(condition))                                               \
393                 __wait_event_killable(wq, condition, __ret);            \
394         __ret;                                                          \
395 })
396
397 /*
398  * Must be called with the spinlock in the wait_queue_head_t held.
399  */
400 static inline void add_wait_queue_exclusive_locked(wait_queue_head_t *q,
401                                                    wait_queue_t * wait)
402 {
403         wait->flags |= WQ_FLAG_EXCLUSIVE;
404         __add_wait_queue_tail(q,  wait);
405 }
406
407 /*
408  * Must be called with the spinlock in the wait_queue_head_t held.
409  */
410 static inline void remove_wait_queue_locked(wait_queue_head_t *q,
411                                             wait_queue_t * wait)
412 {
413         __remove_wait_queue(q,  wait);
414 }
415
416 /*
417  * These are the old interfaces to sleep waiting for an event.
418  * They are racy.  DO NOT use them, use the wait_event* interfaces above.
419  * We plan to remove these interfaces.
420  */
421 extern void sleep_on(wait_queue_head_t *q);
422 extern long sleep_on_timeout(wait_queue_head_t *q,
423                                       signed long timeout);
424 extern void interruptible_sleep_on(wait_queue_head_t *q);
425 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
426                                            signed long timeout);
427
428 /*
429  * Waitqueues which are removed from the waitqueue_head at wakeup time
430  */
431 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
432 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
433 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
434 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
435 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
436
437 #define DEFINE_WAIT(name)                                               \
438         wait_queue_t name = {                                           \
439                 .private        = current,                              \
440                 .func           = autoremove_wake_function,             \
441                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
442         }
443
444 #define DEFINE_WAIT_BIT(name, word, bit)                                \
445         struct wait_bit_queue name = {                                  \
446                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
447                 .wait   = {                                             \
448                         .private        = current,                      \
449                         .func           = wake_bit_function,            \
450                         .task_list      =                               \
451                                 LIST_HEAD_INIT((name).wait.task_list),  \
452                 },                                                      \
453         }
454
455 #define init_wait(wait)                                                 \
456         do {                                                            \
457                 (wait)->private = current;                              \
458                 (wait)->func = autoremove_wake_function;                \
459                 INIT_LIST_HEAD(&(wait)->task_list);                     \
460         } while (0)
461
462 /**
463  * wait_on_bit - wait for a bit to be cleared
464  * @word: the word being waited on, a kernel virtual address
465  * @bit: the bit of the word being waited on
466  * @action: the function used to sleep, which may take special actions
467  * @mode: the task state to sleep in
468  *
469  * There is a standard hashed waitqueue table for generic use. This
470  * is the part of the hashtable's accessor API that waits on a bit.
471  * For instance, if one were to have waiters on a bitflag, one would
472  * call wait_on_bit() in threads waiting for the bit to clear.
473  * One uses wait_on_bit() where one is waiting for the bit to clear,
474  * but has no intention of setting it.
475  */
476 static inline int wait_on_bit(void *word, int bit,
477                                 int (*action)(void *), unsigned mode)
478 {
479         if (!test_bit(bit, word))
480                 return 0;
481         return out_of_line_wait_on_bit(word, bit, action, mode);
482 }
483
484 /**
485  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
486  * @word: the word being waited on, a kernel virtual address
487  * @bit: the bit of the word being waited on
488  * @action: the function used to sleep, which may take special actions
489  * @mode: the task state to sleep in
490  *
491  * There is a standard hashed waitqueue table for generic use. This
492  * is the part of the hashtable's accessor API that waits on a bit
493  * when one intends to set it, for instance, trying to lock bitflags.
494  * For instance, if one were to have waiters trying to set bitflag
495  * and waiting for it to clear before setting it, one would call
496  * wait_on_bit() in threads waiting to be able to set the bit.
497  * One uses wait_on_bit_lock() where one is waiting for the bit to
498  * clear with the intention of setting it, and when done, clearing it.
499  */
500 static inline int wait_on_bit_lock(void *word, int bit,
501                                 int (*action)(void *), unsigned mode)
502 {
503         if (!test_and_set_bit(bit, word))
504                 return 0;
505         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
506 }
507         
508 #endif /* __KERNEL__ */
509
510 #endif