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Linux v2.6.15-rc6
[pohmelfs.git] / include / linux / wait.h
blobd28518236b62fea581606ee74c76607743153aad
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 struct task_struct;
58
59 /*
60 * Macros for declaration and initialisaton of the datatypes
61 */
62
63 #define __WAITQUEUE_INITIALIZER(name, tsk) { \
64 .private = tsk, \
65 .func = default_wake_function, \
66 .task_list = { NULL, NULL } }
67
68 #define DECLARE_WAITQUEUE(name, tsk) \
69 wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
70
71 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \
72 .lock = SPIN_LOCK_UNLOCKED, \
73 .task_list = { &(name).task_list, &(name).task_list } }
74
75 #define DECLARE_WAIT_QUEUE_HEAD(name) \
76 wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
77
78 #define __WAIT_BIT_KEY_INITIALIZER(word, bit) \
79 { .flags = word, .bit_nr = bit, }
80
81 static inline void init_waitqueue_head(wait_queue_head_t *q)
82 {
83 spin_lock_init(&q->lock);
84 INIT_LIST_HEAD(&q->task_list);
85 }
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 init_waitqueue_func_entry(wait_queue_t *q,
95 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 /*
108 * Used to distinguish between sync and async io wait context:
109 * sync i/o typically specifies a NULL wait queue entry or a wait
110 * queue entry bound to a task (current task) to wake up.
111 * aio specifies a wait queue entry with an async notification
112 * callback routine, not associated with any task.
113 */
114 #define is_sync_wait(wait) (!(wait) || ((wait)->private))
115
116 extern void FASTCALL(add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
117 extern void FASTCALL(add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t * wait));
118 extern void FASTCALL(remove_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
119
120 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
121 {
122 list_add(&new->task_list, &head->task_list);
123 }
124
125 /*
126 * Used for wake-one threads:
127 */
128 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
129 wait_queue_t *new)
130 {
131 list_add_tail(&new->task_list, &head->task_list);
132 }
133
134 static inline void __remove_wait_queue(wait_queue_head_t *head,
135 wait_queue_t *old)
136 {
137 list_del(&old->task_list);
138 }
139
140 void FASTCALL(__wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key));
141 extern void FASTCALL(__wake_up_locked(wait_queue_head_t *q, unsigned int mode));
142 extern void FASTCALL(__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr));
143 void FASTCALL(__wake_up_bit(wait_queue_head_t *, void *, int));
144 int FASTCALL(__wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned));
145 int FASTCALL(__wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned));
146 void FASTCALL(wake_up_bit(void *, int));
147 int FASTCALL(out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned));
148 int FASTCALL(out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned));
149 wait_queue_head_t *FASTCALL(bit_waitqueue(void *, int));
150
151 #define wake_up(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1, NULL)
152 #define wake_up_nr(x, nr) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr, NULL)
153 #define wake_up_all(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 0, NULL)
154 #define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
155 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
156 #define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
157 #define wake_up_locked(x) __wake_up_locked((x), TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE)
158 #define wake_up_interruptible_sync(x) __wake_up_sync((x),TASK_INTERRUPTIBLE, 1)
159
160 #define __wait_event(wq, condition) \
161 do { \
162 DEFINE_WAIT(__wait); \
163 \
164 for (;;) { \
165 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
166 if (condition) \
167 break; \
168 schedule(); \
169 } \
170 finish_wait(&wq, &__wait); \
171 } while (0)
172
173 /**
174 * wait_event - sleep until a condition gets true
175 * @wq: the waitqueue to wait on
176 * @condition: a C expression for the event to wait for
177 *
178 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
179 * @condition evaluates to true. The @condition is checked each time
180 * the waitqueue @wq is woken up.
181 *
182 * wake_up() has to be called after changing any variable that could
183 * change the result of the wait condition.
184 */
185 #define wait_event(wq, condition) \
186 do { \
187 if (condition) \
188 break; \
189 __wait_event(wq, condition); \
190 } while (0)
191
192 #define __wait_event_timeout(wq, condition, ret) \
193 do { \
194 DEFINE_WAIT(__wait); \
195 \
196 for (;;) { \
197 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
198 if (condition) \
199 break; \
200 ret = schedule_timeout(ret); \
201 if (!ret) \
202 break; \
203 } \
204 finish_wait(&wq, &__wait); \
205 } while (0)
206
207 /**
208 * wait_event_timeout - sleep until a condition gets true or a timeout elapses
209 * @wq: the waitqueue to wait on
210 * @condition: a C expression for the event to wait for
211 * @timeout: timeout, in jiffies
212 *
213 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
214 * @condition evaluates to true. The @condition is checked each time
215 * the waitqueue @wq is woken up.
216 *
217 * wake_up() has to be called after changing any variable that could
218 * change the result of the wait condition.
219 *
220 * The function returns 0 if the @timeout elapsed, and the remaining
221 * jiffies if the condition evaluated to true before the timeout elapsed.
222 */
223 #define wait_event_timeout(wq, condition, timeout) \
224 ({ \
225 long __ret = timeout; \
226 if (!(condition)) \
227 __wait_event_timeout(wq, condition, __ret); \
228 __ret; \
229 })
230
231 #define __wait_event_interruptible(wq, condition, ret) \
232 do { \
233 DEFINE_WAIT(__wait); \
234 \
235 for (;;) { \
236 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
237 if (condition) \
238 break; \
239 if (!signal_pending(current)) { \
240 schedule(); \
241 continue; \
242 } \
243 ret = -ERESTARTSYS; \
244 break; \
245 } \
246 finish_wait(&wq, &__wait); \
247 } while (0)
248
249 /**
250 * wait_event_interruptible - sleep until a condition gets true
251 * @wq: the waitqueue to wait on
252 * @condition: a C expression for the event to wait for
253 *
254 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
255 * @condition evaluates to true or a signal is received.
256 * The @condition is checked each time the waitqueue @wq is woken up.
257 *
258 * wake_up() has to be called after changing any variable that could
259 * change the result of the wait condition.
260 *
261 * The function will return -ERESTARTSYS if it was interrupted by a
262 * signal and 0 if @condition evaluated to true.
263 */
264 #define wait_event_interruptible(wq, condition) \
265 ({ \
266 int __ret = 0; \
267 if (!(condition)) \
268 __wait_event_interruptible(wq, condition, __ret); \
269 __ret; \
270 })
271
272 #define __wait_event_interruptible_timeout(wq, condition, ret) \
273 do { \
274 DEFINE_WAIT(__wait); \
275 \
276 for (;;) { \
277 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
278 if (condition) \
279 break; \
280 if (!signal_pending(current)) { \
281 ret = schedule_timeout(ret); \
282 if (!ret) \
283 break; \
284 continue; \
285 } \
286 ret = -ERESTARTSYS; \
287 break; \
288 } \
289 finish_wait(&wq, &__wait); \
290 } while (0)
291
292 /**
293 * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
294 * @wq: the waitqueue to wait on
295 * @condition: a C expression for the event to wait for
296 * @timeout: timeout, in jiffies
297 *
298 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
299 * @condition evaluates to true or a signal is received.
300 * The @condition is checked each time the waitqueue @wq is woken up.
301 *
302 * wake_up() has to be called after changing any variable that could
303 * change the result of the wait condition.
304 *
305 * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
306 * was interrupted by a signal, and the remaining jiffies otherwise
307 * if the condition evaluated to true before the timeout elapsed.
308 */
309 #define wait_event_interruptible_timeout(wq, condition, timeout) \
310 ({ \
311 long __ret = timeout; \
312 if (!(condition)) \
313 __wait_event_interruptible_timeout(wq, condition, __ret); \
314 __ret; \
315 })
316
317 #define __wait_event_interruptible_exclusive(wq, condition, ret) \
318 do { \
319 DEFINE_WAIT(__wait); \
320 \
321 for (;;) { \
322 prepare_to_wait_exclusive(&wq, &__wait, \
323 TASK_INTERRUPTIBLE); \
324 if (condition) \
325 break; \
326 if (!signal_pending(current)) { \
327 schedule(); \
328 continue; \
329 } \
330 ret = -ERESTARTSYS; \
331 break; \
332 } \
333 finish_wait(&wq, &__wait); \
334 } while (0)
335
336 #define wait_event_interruptible_exclusive(wq, condition) \
337 ({ \
338 int __ret = 0; \
339 if (!(condition)) \
340 __wait_event_interruptible_exclusive(wq, condition, __ret);\
341 __ret; \
342 })
343
344 /*
345 * Must be called with the spinlock in the wait_queue_head_t held.
346 */
347 static inline void add_wait_queue_exclusive_locked(wait_queue_head_t *q,
348 wait_queue_t * wait)
349 {
350 wait->flags |= WQ_FLAG_EXCLUSIVE;
351 __add_wait_queue_tail(q, wait);
352 }
353
354 /*
355 * Must be called with the spinlock in the wait_queue_head_t held.
356 */
357 static inline void remove_wait_queue_locked(wait_queue_head_t *q,
358 wait_queue_t * wait)
359 {
360 __remove_wait_queue(q, wait);
361 }
362
363 /*
364 * These are the old interfaces to sleep waiting for an event.
365 * They are racy. DO NOT use them, use the wait_event* interfaces above.
366 * We plan to remove these interfaces during 2.7.
367 */
368 extern void FASTCALL(sleep_on(wait_queue_head_t *q));
369 extern long FASTCALL(sleep_on_timeout(wait_queue_head_t *q,
370 signed long timeout));
371 extern void FASTCALL(interruptible_sleep_on(wait_queue_head_t *q));
372 extern long FASTCALL(interruptible_sleep_on_timeout(wait_queue_head_t *q,
373 signed long timeout));
374
375 /*
376 * Waitqueues which are removed from the waitqueue_head at wakeup time
377 */
378 void FASTCALL(prepare_to_wait(wait_queue_head_t *q,
379 wait_queue_t *wait, int state));
380 void FASTCALL(prepare_to_wait_exclusive(wait_queue_head_t *q,
381 wait_queue_t *wait, int state));
382 void FASTCALL(finish_wait(wait_queue_head_t *q, wait_queue_t *wait));
383 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
384 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
385
386 #define DEFINE_WAIT(name) \
387 wait_queue_t name = { \
388 .private = current, \
389 .func = autoremove_wake_function, \
390 .task_list = LIST_HEAD_INIT((name).task_list), \
391 }
392
393 #define DEFINE_WAIT_BIT(name, word, bit) \
394 struct wait_bit_queue name = { \
395 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \
396 .wait = { \
397 .private = current, \
398 .func = wake_bit_function, \
399 .task_list = \
400 LIST_HEAD_INIT((name).wait.task_list), \
401 }, \
402 }
403
404 #define init_wait(wait) \
405 do { \
406 (wait)->private = current; \
407 (wait)->func = autoremove_wake_function; \
408 INIT_LIST_HEAD(&(wait)->task_list); \
409 } while (0)
410
411 /**
412 * wait_on_bit - wait for a bit to be cleared
413 * @word: the word being waited on, a kernel virtual address
414 * @bit: the bit of the word being waited on
415 * @action: the function used to sleep, which may take special actions
416 * @mode: the task state to sleep in
417 *
418 * There is a standard hashed waitqueue table for generic use. This
419 * is the part of the hashtable's accessor API that waits on a bit.
420 * For instance, if one were to have waiters on a bitflag, one would
421 * call wait_on_bit() in threads waiting for the bit to clear.
422 * One uses wait_on_bit() where one is waiting for the bit to clear,
423 * but has no intention of setting it.
424 */
425 static inline int wait_on_bit(void *word, int bit,
426 int (*action)(void *), unsigned mode)
427 {
428 if (!test_bit(bit, word))
429 return 0;
430 return out_of_line_wait_on_bit(word, bit, action, mode);
431 }
432
433 /**
434 * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
435 * @word: the word being waited on, a kernel virtual address
436 * @bit: the bit of the word being waited on
437 * @action: the function used to sleep, which may take special actions
438 * @mode: the task state to sleep in
439 *
440 * There is a standard hashed waitqueue table for generic use. This
441 * is the part of the hashtable's accessor API that waits on a bit
442 * when one intends to set it, for instance, trying to lock bitflags.
443 * For instance, if one were to have waiters trying to set bitflag
444 * and waiting for it to clear before setting it, one would call
445 * wait_on_bit() in threads waiting to be able to set the bit.
446 * One uses wait_on_bit_lock() where one is waiting for the bit to
447 * clear with the intention of setting it, and when done, clearing it.
448 */
449 static inline int wait_on_bit_lock(void *word, int bit,
450 int (*action)(void *), unsigned mode)
451 {
452 if (!test_and_set_bit(bit, word))
453 return 0;
454 return out_of_line_wait_on_bit_lock(word, bit, action, mode);
455 }
456
457 #endif /* __KERNEL__ */
458
459 #endif