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Linux 2.6.33-rc2
[pohmelfs.git] / include / linux / wait.h
bloba48e16b77d5e2d94c1bb1bfb6b5efa56a82bd7af
1 #ifndef _LINUX_WAIT_H
2 #define _LINUX_WAIT_H
3
4 #define WNOHANG 0x00000001
5 #define WUNTRACED 0x00000002
6 #define WSTOPPED WUNTRACED
7 #define WEXITED 0x00000004
8 #define WCONTINUED 0x00000008
9 #define WNOWAIT 0x01000000 /* Don't reap, just poll status. */
10
11 #define __WNOTHREAD 0x20000000 /* Don't wait on children of other threads in this group */
12 #define __WALL 0x40000000 /* Wait on all children, regardless of type */
13 #define __WCLONE 0x80000000 /* Wait only on non-SIGCHLD children */
14
15 /* First argument to waitid: */
16 #define P_ALL 0
17 #define P_PID 1
18 #define P_PGID 2
19
20 #ifdef __KERNEL__
21
22 #include <linux/list.h>
23 #include <linux/stddef.h>
24 #include <linux/spinlock.h>
25 #include <asm/system.h>
26 #include <asm/current.h>
27
28 typedef struct __wait_queue wait_queue_t;
29 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key);
30 int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, void *key);
31
32 struct __wait_queue {
33 unsigned int flags;
34 #define WQ_FLAG_EXCLUSIVE 0x01
35 void *private;
36 wait_queue_func_t func;
37 struct list_head task_list;
38 };
39
40 struct wait_bit_key {
41 void *flags;
42 int bit_nr;
43 };
44
45 struct wait_bit_queue {
46 struct wait_bit_key key;
47 wait_queue_t wait;
48 };
49
50 struct __wait_queue_head {
51 spinlock_t lock;
52 struct list_head task_list;
53 };
54 typedef struct __wait_queue_head wait_queue_head_t;
55
56 struct task_struct;
57
58 /*
59 * Macros for declaration and initialisaton of the datatypes
60 */
61
62 #define __WAITQUEUE_INITIALIZER(name, tsk) { \
63 .private = tsk, \
64 .func = default_wake_function, \
65 .task_list = { NULL, NULL } }
66
67 #define DECLARE_WAITQUEUE(name, tsk) \
68 wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
69
70 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \
71 .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
72 .task_list = { &(name).task_list, &(name).task_list } }
73
74 #define DECLARE_WAIT_QUEUE_HEAD(name) \
75 wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
76
77 #define __WAIT_BIT_KEY_INITIALIZER(word, bit) \
78 { .flags = word, .bit_nr = bit, }
79
80 extern void __init_waitqueue_head(wait_queue_head_t *q, struct lock_class_key *);
81
82 #define init_waitqueue_head(q) \
83 do { \
84 static struct lock_class_key __key; \
85 \
86 __init_waitqueue_head((q), &__key); \
87 } while (0)
88
89 #ifdef CONFIG_LOCKDEP
90 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
91 ({ init_waitqueue_head(&name); name; })
92 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
93 wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
94 #else
95 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
96 #endif
97
98 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
99 {
100 q->flags = 0;
101 q->private = p;
102 q->func = default_wake_function;
103 }
104
105 static inline void init_waitqueue_func_entry(wait_queue_t *q,
106 wait_queue_func_t func)
107 {
108 q->flags = 0;
109 q->private = NULL;
110 q->func = func;
111 }
112
113 static inline int waitqueue_active(wait_queue_head_t *q)
114 {
115 return !list_empty(&q->task_list);
116 }
117
118 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
119 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
120 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
121
122 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
123 {
124 list_add(&new->task_list, &head->task_list);
125 }
126
127 /*
128 * Used for wake-one threads:
129 */
130 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
131 wait_queue_t *new)
132 {
133 list_add_tail(&new->task_list, &head->task_list);
134 }
135
136 static inline void __remove_wait_queue(wait_queue_head_t *head,
137 wait_queue_t *old)
138 {
139 list_del(&old->task_list);
140 }
141
142 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
143 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
144 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr,
145 void *key);
146 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode);
147 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
148 void __wake_up_bit(wait_queue_head_t *, void *, int);
149 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
150 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
151 void wake_up_bit(void *, int);
152 int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned);
153 int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned);
154 wait_queue_head_t *bit_waitqueue(void *, int);
155
156 #define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL)
157 #define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL)
158 #define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL)
159 #define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL)
160
161 #define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
162 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
163 #define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
164 #define wake_up_interruptible_sync(x) __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
165
166 /*
167 * Wakeup macros to be used to report events to the targets.
168 */
169 #define wake_up_poll(x, m) \
170 __wake_up(x, TASK_NORMAL, 1, (void *) (m))
171 #define wake_up_locked_poll(x, m) \
172 __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
173 #define wake_up_interruptible_poll(x, m) \
174 __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
175 #define wake_up_interruptible_sync_poll(x, m) \
176 __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
177
178 #define __wait_event(wq, condition) \
179 do { \
180 DEFINE_WAIT(__wait); \
181 \
182 for (;;) { \
183 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
184 if (condition) \
185 break; \
186 schedule(); \
187 } \
188 finish_wait(&wq, &__wait); \
189 } while (0)
190
191 /**
192 * wait_event - sleep until a condition gets true
193 * @wq: the waitqueue to wait on
194 * @condition: a C expression for the event to wait for
195 *
196 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
197 * @condition evaluates to true. The @condition is checked each time
198 * the waitqueue @wq is woken up.
199 *
200 * wake_up() has to be called after changing any variable that could
201 * change the result of the wait condition.
202 */
203 #define wait_event(wq, condition) \
204 do { \
205 if (condition) \
206 break; \
207 __wait_event(wq, condition); \
208 } while (0)
209
210 #define __wait_event_timeout(wq, condition, ret) \
211 do { \
212 DEFINE_WAIT(__wait); \
213 \
214 for (;;) { \
215 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
216 if (condition) \
217 break; \
218 ret = schedule_timeout(ret); \
219 if (!ret) \
220 break; \
221 } \
222 finish_wait(&wq, &__wait); \
223 } while (0)
224
225 /**
226 * wait_event_timeout - sleep until a condition gets true or a timeout elapses
227 * @wq: the waitqueue to wait on
228 * @condition: a C expression for the event to wait for
229 * @timeout: timeout, in jiffies
230 *
231 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
232 * @condition evaluates to true. The @condition is checked each time
233 * the waitqueue @wq is woken up.
234 *
235 * wake_up() has to be called after changing any variable that could
236 * change the result of the wait condition.
237 *
238 * The function returns 0 if the @timeout elapsed, and the remaining
239 * jiffies if the condition evaluated to true before the timeout elapsed.
240 */
241 #define wait_event_timeout(wq, condition, timeout) \
242 ({ \
243 long __ret = timeout; \
244 if (!(condition)) \
245 __wait_event_timeout(wq, condition, __ret); \
246 __ret; \
247 })
248
249 #define __wait_event_interruptible(wq, condition, ret) \
250 do { \
251 DEFINE_WAIT(__wait); \
252 \
253 for (;;) { \
254 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
255 if (condition) \
256 break; \
257 if (!signal_pending(current)) { \
258 schedule(); \
259 continue; \
260 } \
261 ret = -ERESTARTSYS; \
262 break; \
263 } \
264 finish_wait(&wq, &__wait); \
265 } while (0)
266
267 /**
268 * wait_event_interruptible - sleep until a condition gets true
269 * @wq: the waitqueue to wait on
270 * @condition: a C expression for the event to wait for
271 *
272 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
273 * @condition evaluates to true or a signal is received.
274 * The @condition is checked each time the waitqueue @wq is woken up.
275 *
276 * wake_up() has to be called after changing any variable that could
277 * change the result of the wait condition.
278 *
279 * The function will return -ERESTARTSYS if it was interrupted by a
280 * signal and 0 if @condition evaluated to true.
281 */
282 #define wait_event_interruptible(wq, condition) \
283 ({ \
284 int __ret = 0; \
285 if (!(condition)) \
286 __wait_event_interruptible(wq, condition, __ret); \
287 __ret; \
288 })
289
290 #define __wait_event_interruptible_timeout(wq, condition, ret) \
291 do { \
292 DEFINE_WAIT(__wait); \
293 \
294 for (;;) { \
295 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
296 if (condition) \
297 break; \
298 if (!signal_pending(current)) { \
299 ret = schedule_timeout(ret); \
300 if (!ret) \
301 break; \
302 continue; \
303 } \
304 ret = -ERESTARTSYS; \
305 break; \
306 } \
307 finish_wait(&wq, &__wait); \
308 } while (0)
309
310 /**
311 * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
312 * @wq: the waitqueue to wait on
313 * @condition: a C expression for the event to wait for
314 * @timeout: timeout, in jiffies
315 *
316 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
317 * @condition evaluates to true or a signal is received.
318 * The @condition is checked each time the waitqueue @wq is woken up.
319 *
320 * wake_up() has to be called after changing any variable that could
321 * change the result of the wait condition.
322 *
323 * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
324 * was interrupted by a signal, and the remaining jiffies otherwise
325 * if the condition evaluated to true before the timeout elapsed.
326 */
327 #define wait_event_interruptible_timeout(wq, condition, timeout) \
328 ({ \
329 long __ret = timeout; \
330 if (!(condition)) \
331 __wait_event_interruptible_timeout(wq, condition, __ret); \
332 __ret; \
333 })
334
335 #define __wait_event_interruptible_exclusive(wq, condition, ret) \
336 do { \
337 DEFINE_WAIT(__wait); \
338 \
339 for (;;) { \
340 prepare_to_wait_exclusive(&wq, &__wait, \
341 TASK_INTERRUPTIBLE); \
342 if (condition) { \
343 finish_wait(&wq, &__wait); \
344 break; \
345 } \
346 if (!signal_pending(current)) { \
347 schedule(); \
348 continue; \
349 } \
350 ret = -ERESTARTSYS; \
351 abort_exclusive_wait(&wq, &__wait, \
352 TASK_INTERRUPTIBLE, NULL); \
353 break; \
354 } \
355 } while (0)
356
357 #define wait_event_interruptible_exclusive(wq, condition) \
358 ({ \
359 int __ret = 0; \
360 if (!(condition)) \
361 __wait_event_interruptible_exclusive(wq, condition, __ret);\
362 __ret; \
363 })
364
365 #define __wait_event_killable(wq, condition, ret) \
366 do { \
367 DEFINE_WAIT(__wait); \
368 \
369 for (;;) { \
370 prepare_to_wait(&wq, &__wait, TASK_KILLABLE); \
371 if (condition) \
372 break; \
373 if (!fatal_signal_pending(current)) { \
374 schedule(); \
375 continue; \
376 } \
377 ret = -ERESTARTSYS; \
378 break; \
379 } \
380 finish_wait(&wq, &__wait); \
381 } while (0)
382
383 /**
384 * wait_event_killable - sleep until a condition gets true
385 * @wq: the waitqueue to wait on
386 * @condition: a C expression for the event to wait for
387 *
388 * The process is put to sleep (TASK_KILLABLE) until the
389 * @condition evaluates to true or a signal is received.
390 * The @condition is checked each time the waitqueue @wq is woken up.
391 *
392 * wake_up() has to be called after changing any variable that could
393 * change the result of the wait condition.
394 *
395 * The function will return -ERESTARTSYS if it was interrupted by a
396 * signal and 0 if @condition evaluated to true.
397 */
398 #define wait_event_killable(wq, condition) \
399 ({ \
400 int __ret = 0; \
401 if (!(condition)) \
402 __wait_event_killable(wq, condition, __ret); \
403 __ret; \
404 })
405
406 /*
407 * Must be called with the spinlock in the wait_queue_head_t held.
408 */
409 static inline void add_wait_queue_exclusive_locked(wait_queue_head_t *q,
410 wait_queue_t * wait)
411 {
412 wait->flags |= WQ_FLAG_EXCLUSIVE;
413 __add_wait_queue_tail(q, wait);
414 }
415
416 /*
417 * Must be called with the spinlock in the wait_queue_head_t held.
418 */
419 static inline void remove_wait_queue_locked(wait_queue_head_t *q,
420 wait_queue_t * wait)
421 {
422 __remove_wait_queue(q, wait);
423 }
424
425 /*
426 * These are the old interfaces to sleep waiting for an event.
427 * They are racy. DO NOT use them, use the wait_event* interfaces above.
428 * We plan to remove these interfaces.
429 */
430 extern void sleep_on(wait_queue_head_t *q);
431 extern long sleep_on_timeout(wait_queue_head_t *q,
432 signed long timeout);
433 extern void interruptible_sleep_on(wait_queue_head_t *q);
434 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
435 signed long timeout);
436
437 /*
438 * Waitqueues which are removed from the waitqueue_head at wakeup time
439 */
440 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
441 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
442 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
443 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
444 unsigned int mode, void *key);
445 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
446 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
447
448 #define DEFINE_WAIT_FUNC(name, function) \
449 wait_queue_t name = { \
450 .private = current, \
451 .func = function, \
452 .task_list = LIST_HEAD_INIT((name).task_list), \
453 }
454
455 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
456
457 #define DEFINE_WAIT_BIT(name, word, bit) \
458 struct wait_bit_queue name = { \
459 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \
460 .wait = { \
461 .private = current, \
462 .func = wake_bit_function, \
463 .task_list = \
464 LIST_HEAD_INIT((name).wait.task_list), \
465 }, \
466 }
467
468 #define init_wait(wait) \
469 do { \
470 (wait)->private = current; \
471 (wait)->func = autoremove_wake_function; \
472 INIT_LIST_HEAD(&(wait)->task_list); \
473 } while (0)
474
475 /**
476 * wait_on_bit - wait for a bit to be cleared
477 * @word: the word being waited on, a kernel virtual address
478 * @bit: the bit of the word being waited on
479 * @action: the function used to sleep, which may take special actions
480 * @mode: the task state to sleep in
481 *
482 * There is a standard hashed waitqueue table for generic use. This
483 * is the part of the hashtable's accessor API that waits on a bit.
484 * For instance, if one were to have waiters on a bitflag, one would
485 * call wait_on_bit() in threads waiting for the bit to clear.
486 * One uses wait_on_bit() where one is waiting for the bit to clear,
487 * but has no intention of setting it.
488 */
489 static inline int wait_on_bit(void *word, int bit,
490 int (*action)(void *), unsigned mode)
491 {
492 if (!test_bit(bit, word))
493 return 0;
494 return out_of_line_wait_on_bit(word, bit, action, mode);
495 }
496
497 /**
498 * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
499 * @word: the word being waited on, a kernel virtual address
500 * @bit: the bit of the word being waited on
501 * @action: the function used to sleep, which may take special actions
502 * @mode: the task state to sleep in
503 *
504 * There is a standard hashed waitqueue table for generic use. This
505 * is the part of the hashtable's accessor API that waits on a bit
506 * when one intends to set it, for instance, trying to lock bitflags.
507 * For instance, if one were to have waiters trying to set bitflag
508 * and waiting for it to clear before setting it, one would call
509 * wait_on_bit() in threads waiting to be able to set the bit.
510 * One uses wait_on_bit_lock() where one is waiting for the bit to
511 * clear with the intention of setting it, and when done, clearing it.
512 */
513 static inline int wait_on_bit_lock(void *word, int bit,
514 int (*action)(void *), unsigned mode)
515 {
516 if (!test_and_set_bit(bit, word))
517 return 0;
518 return out_of_line_wait_on_bit_lock(word, bit, action, mode);
519 }
520
521 #endif /* __KERNEL__ */
522
523 #endif