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[CONNECTOR]: Update documentation to match reality.
[linux-2.6/verdex.git] / include / linux / wait.h
blobd38c9fecdc368450d00a4e5602944b0288a2c64b
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/config.h>
23 #include <linux/list.h>
24 #include <linux/stddef.h>
25 #include <linux/spinlock.h>
26 #include <asm/system.h>
27 #include <asm/current.h>
28
29 typedef struct __wait_queue wait_queue_t;
30 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int sync, void *key);
31 int default_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
32
33 struct __wait_queue {
34 unsigned int flags;
35 #define WQ_FLAG_EXCLUSIVE 0x01
36 void *private;
37 wait_queue_func_t func;
38 struct list_head task_list;
39 };
40
41 struct wait_bit_key {
42 void *flags;
43 int bit_nr;
44 };
45
46 struct wait_bit_queue {
47 struct wait_bit_key key;
48 wait_queue_t wait;
49 };
50
51 struct __wait_queue_head {
52 spinlock_t lock;
53 struct list_head task_list;
54 };
55 typedef struct __wait_queue_head wait_queue_head_t;
56
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, \
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 static inline void init_waitqueue_head(wait_queue_head_t *q)
81 {
82 spin_lock_init(&q->lock);
83 INIT_LIST_HEAD(&q->task_list);
84 }
85
86 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
87 {
88 q->flags = 0;
89 q->private = p;
90 q->func = default_wake_function;
91 }
92
93 static inline void init_waitqueue_func_entry(wait_queue_t *q,
94 wait_queue_func_t func)
95 {
96 q->flags = 0;
97 q->private = NULL;
98 q->func = func;
99 }
100
101 static inline int waitqueue_active(wait_queue_head_t *q)
102 {
103 return !list_empty(&q->task_list);
104 }
105
106 /*
107 * Used to distinguish between sync and async io wait context:
108 * sync i/o typically specifies a NULL wait queue entry or a wait
109 * queue entry bound to a task (current task) to wake up.
110 * aio specifies a wait queue entry with an async notification
111 * callback routine, not associated with any task.
112 */
113 #define is_sync_wait(wait) (!(wait) || ((wait)->private))
114
115 extern void FASTCALL(add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
116 extern void FASTCALL(add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t * wait));
117 extern void FASTCALL(remove_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
118
119 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
120 {
121 list_add(&new->task_list, &head->task_list);
122 }
123
124 /*
125 * Used for wake-one threads:
126 */
127 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
128 wait_queue_t *new)
129 {
130 list_add_tail(&new->task_list, &head->task_list);
131 }
132
133 static inline void __remove_wait_queue(wait_queue_head_t *head,
134 wait_queue_t *old)
135 {
136 list_del(&old->task_list);
137 }
138
139 void FASTCALL(__wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key));
140 extern void FASTCALL(__wake_up_locked(wait_queue_head_t *q, unsigned int mode));
141 extern void FASTCALL(__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr));
142 void FASTCALL(__wake_up_bit(wait_queue_head_t *, void *, int));
143 int FASTCALL(__wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned));
144 int FASTCALL(__wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned));
145 void FASTCALL(wake_up_bit(void *, int));
146 int FASTCALL(out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned));
147 int FASTCALL(out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned));
148 wait_queue_head_t *FASTCALL(bit_waitqueue(void *, int));
149
150 #define wake_up(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1, NULL)
151 #define wake_up_nr(x, nr) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr, NULL)
152 #define wake_up_all(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 0, NULL)
153 #define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
154 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
155 #define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
156 #define wake_up_locked(x) __wake_up_locked((x), TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE)
157 #define wake_up_interruptible_sync(x) __wake_up_sync((x),TASK_INTERRUPTIBLE, 1)
158
159 #define __wait_event(wq, condition) \
160 do { \
161 DEFINE_WAIT(__wait); \
162 \
163 for (;;) { \
164 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
165 if (condition) \
166 break; \
167 schedule(); \
168 } \
169 finish_wait(&wq, &__wait); \
170 } while (0)
171
172 /**
173 * wait_event - sleep until a condition gets true
174 * @wq: the waitqueue to wait on
175 * @condition: a C expression for the event to wait for
176 *
177 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
178 * @condition evaluates to true. The @condition is checked each time
179 * the waitqueue @wq is woken up.
180 *
181 * wake_up() has to be called after changing any variable that could
182 * change the result of the wait condition.
183 */
184 #define wait_event(wq, condition) \
185 do { \
186 if (condition) \
187 break; \
188 __wait_event(wq, condition); \
189 } while (0)
190
191 #define __wait_event_timeout(wq, condition, ret) \
192 do { \
193 DEFINE_WAIT(__wait); \
194 \
195 for (;;) { \
196 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
197 if (condition) \
198 break; \
199 ret = schedule_timeout(ret); \
200 if (!ret) \
201 break; \
202 } \
203 finish_wait(&wq, &__wait); \
204 } while (0)
205
206 /**
207 * wait_event_timeout - sleep until a condition gets true or a timeout elapses
208 * @wq: the waitqueue to wait on
209 * @condition: a C expression for the event to wait for
210 * @timeout: timeout, in jiffies
211 *
212 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
213 * @condition evaluates to true. The @condition is checked each time
214 * the waitqueue @wq is woken up.
215 *
216 * wake_up() has to be called after changing any variable that could
217 * change the result of the wait condition.
218 *
219 * The function returns 0 if the @timeout elapsed, and the remaining
220 * jiffies if the condition evaluated to true before the timeout elapsed.
221 */
222 #define wait_event_timeout(wq, condition, timeout) \
223 ({ \
224 long __ret = timeout; \
225 if (!(condition)) \
226 __wait_event_timeout(wq, condition, __ret); \
227 __ret; \
228 })
229
230 #define __wait_event_interruptible(wq, condition, ret) \
231 do { \
232 DEFINE_WAIT(__wait); \
233 \
234 for (;;) { \
235 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
236 if (condition) \
237 break; \
238 if (!signal_pending(current)) { \
239 schedule(); \
240 continue; \
241 } \
242 ret = -ERESTARTSYS; \
243 break; \
244 } \
245 finish_wait(&wq, &__wait); \
246 } while (0)
247
248 /**
249 * wait_event_interruptible - sleep until a condition gets true
250 * @wq: the waitqueue to wait on
251 * @condition: a C expression for the event to wait for
252 *
253 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
254 * @condition evaluates to true or a signal is received.
255 * The @condition is checked each time the waitqueue @wq is woken up.
256 *
257 * wake_up() has to be called after changing any variable that could
258 * change the result of the wait condition.
259 *
260 * The function will return -ERESTARTSYS if it was interrupted by a
261 * signal and 0 if @condition evaluated to true.
262 */
263 #define wait_event_interruptible(wq, condition) \
264 ({ \
265 int __ret = 0; \
266 if (!(condition)) \
267 __wait_event_interruptible(wq, condition, __ret); \
268 __ret; \
269 })
270
271 #define __wait_event_interruptible_timeout(wq, condition, ret) \
272 do { \
273 DEFINE_WAIT(__wait); \
274 \
275 for (;;) { \
276 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
277 if (condition) \
278 break; \
279 if (!signal_pending(current)) { \
280 ret = schedule_timeout(ret); \
281 if (!ret) \
282 break; \
283 continue; \
284 } \
285 ret = -ERESTARTSYS; \
286 break; \
287 } \
288 finish_wait(&wq, &__wait); \
289 } while (0)
290
291 /**
292 * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
293 * @wq: the waitqueue to wait on
294 * @condition: a C expression for the event to wait for
295 * @timeout: timeout, in jiffies
296 *
297 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
298 * @condition evaluates to true or a signal is received.
299 * The @condition is checked each time the waitqueue @wq is woken up.
300 *
301 * wake_up() has to be called after changing any variable that could
302 * change the result of the wait condition.
303 *
304 * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
305 * was interrupted by a signal, and the remaining jiffies otherwise
306 * if the condition evaluated to true before the timeout elapsed.
307 */
308 #define wait_event_interruptible_timeout(wq, condition, timeout) \
309 ({ \
310 long __ret = timeout; \
311 if (!(condition)) \
312 __wait_event_interruptible_timeout(wq, condition, __ret); \
313 __ret; \
314 })
315
316 #define __wait_event_interruptible_exclusive(wq, condition, ret) \
317 do { \
318 DEFINE_WAIT(__wait); \
319 \
320 for (;;) { \
321 prepare_to_wait_exclusive(&wq, &__wait, \
322 TASK_INTERRUPTIBLE); \
323 if (condition) \
324 break; \
325 if (!signal_pending(current)) { \
326 schedule(); \
327 continue; \
328 } \
329 ret = -ERESTARTSYS; \
330 break; \
331 } \
332 finish_wait(&wq, &__wait); \
333 } while (0)
334
335 #define wait_event_interruptible_exclusive(wq, condition) \
336 ({ \
337 int __ret = 0; \
338 if (!(condition)) \
339 __wait_event_interruptible_exclusive(wq, condition, __ret);\
340 __ret; \
341 })
342
343 /*
344 * Must be called with the spinlock in the wait_queue_head_t held.
345 */
346 static inline void add_wait_queue_exclusive_locked(wait_queue_head_t *q,
347 wait_queue_t * wait)
348 {
349 wait->flags |= WQ_FLAG_EXCLUSIVE;
350 __add_wait_queue_tail(q, wait);
351 }
352
353 /*
354 * Must be called with the spinlock in the wait_queue_head_t held.
355 */
356 static inline void remove_wait_queue_locked(wait_queue_head_t *q,
357 wait_queue_t * wait)
358 {
359 __remove_wait_queue(q, wait);
360 }
361
362 /*
363 * These are the old interfaces to sleep waiting for an event.
364 * They are racy. DO NOT use them, use the wait_event* interfaces above.
365 * We plan to remove these interfaces during 2.7.
366 */
367 extern void FASTCALL(sleep_on(wait_queue_head_t *q));
368 extern long FASTCALL(sleep_on_timeout(wait_queue_head_t *q,
369 signed long timeout));
370 extern void FASTCALL(interruptible_sleep_on(wait_queue_head_t *q));
371 extern long FASTCALL(interruptible_sleep_on_timeout(wait_queue_head_t *q,
372 signed long timeout));
373
374 /*
375 * Waitqueues which are removed from the waitqueue_head at wakeup time
376 */
377 void FASTCALL(prepare_to_wait(wait_queue_head_t *q,
378 wait_queue_t *wait, int state));
379 void FASTCALL(prepare_to_wait_exclusive(wait_queue_head_t *q,
380 wait_queue_t *wait, int state));
381 void FASTCALL(finish_wait(wait_queue_head_t *q, wait_queue_t *wait));
382 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
383 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
384
385 #define DEFINE_WAIT(name) \
386 wait_queue_t name = { \
387 .private = current, \
388 .func = autoremove_wake_function, \
389 .task_list = LIST_HEAD_INIT((name).task_list), \
390 }
391
392 #define DEFINE_WAIT_BIT(name, word, bit) \
393 struct wait_bit_queue name = { \
394 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \
395 .wait = { \
396 .private = current, \
397 .func = wake_bit_function, \
398 .task_list = \
399 LIST_HEAD_INIT((name).wait.task_list), \
400 }, \
401 }
402
403 #define init_wait(wait) \
404 do { \
405 (wait)->private = current; \
406 (wait)->func = autoremove_wake_function; \
407 INIT_LIST_HEAD(&(wait)->task_list); \
408 } while (0)
409
410 /**
411 * wait_on_bit - wait for a bit to be cleared
412 * @word: the word being waited on, a kernel virtual address
413 * @bit: the bit of the word being waited on
414 * @action: the function used to sleep, which may take special actions
415 * @mode: the task state to sleep in
416 *
417 * There is a standard hashed waitqueue table for generic use. This
418 * is the part of the hashtable's accessor API that waits on a bit.
419 * For instance, if one were to have waiters on a bitflag, one would
420 * call wait_on_bit() in threads waiting for the bit to clear.
421 * One uses wait_on_bit() where one is waiting for the bit to clear,
422 * but has no intention of setting it.
423 */
424 static inline int wait_on_bit(void *word, int bit,
425 int (*action)(void *), unsigned mode)
426 {
427 if (!test_bit(bit, word))
428 return 0;
429 return out_of_line_wait_on_bit(word, bit, action, mode);
430 }
431
432 /**
433 * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
434 * @word: the word being waited on, a kernel virtual address
435 * @bit: the bit of the word being waited on
436 * @action: the function used to sleep, which may take special actions
437 * @mode: the task state to sleep in
438 *
439 * There is a standard hashed waitqueue table for generic use. This
440 * is the part of the hashtable's accessor API that waits on a bit
441 * when one intends to set it, for instance, trying to lock bitflags.
442 * For instance, if one were to have waiters trying to set bitflag
443 * and waiting for it to clear before setting it, one would call
444 * wait_on_bit() in threads waiting to be able to set the bit.
445 * One uses wait_on_bit_lock() where one is waiting for the bit to
446 * clear with the intention of setting it, and when done, clearing it.
447 */
448 static inline int wait_on_bit_lock(void *word, int bit,
449 int (*action)(void *), unsigned mode)
450 {
451 if (!test_and_set_bit(bit, word))
452 return 0;
453 return out_of_line_wait_on_bit_lock(word, bit, action, mode);
454 }
455
456 #endif /* __KERNEL__ */
457
458 #endif
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