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s2io.c: Use const for strings
[linux-2.6/mini2440.git] / include / linux / wait.h
blob6788e1a4d4ca63e8cfc3b288f87d456334064c29
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 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
137 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr,
138 void *key);
139 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode);
140 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
141 void __wake_up_bit(wait_queue_head_t *, void *, int);
142 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
143 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
144 void wake_up_bit(void *, int);
145 int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned);
146 int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned);
147 wait_queue_head_t *bit_waitqueue(void *, int);
148
149 #define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL)
150 #define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL)
151 #define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL)
152 #define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL)
153
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_interruptible_sync(x) __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
158
159 /*
160 * Wakeup macros to be used to report events to the targets.
161 */
162 #define wake_up_poll(x, m) \
163 __wake_up(x, TASK_NORMAL, 1, (void *) (m))
164 #define wake_up_locked_poll(x, m) \
165 __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
166 #define wake_up_interruptible_poll(x, m) \
167 __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
168 #define wake_up_interruptible_sync_poll(x, m) \
169 __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
170
171 #define __wait_event(wq, condition) \
172 do { \
173 DEFINE_WAIT(__wait); \
174 \
175 for (;;) { \
176 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
177 if (condition) \
178 break; \
179 schedule(); \
180 } \
181 finish_wait(&wq, &__wait); \
182 } while (0)
183
184 /**
185 * wait_event - sleep until a condition gets true
186 * @wq: the waitqueue to wait on
187 * @condition: a C expression for the event to wait for
188 *
189 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
190 * @condition evaluates to true. The @condition is checked each time
191 * the waitqueue @wq is woken up.
192 *
193 * wake_up() has to be called after changing any variable that could
194 * change the result of the wait condition.
195 */
196 #define wait_event(wq, condition) \
197 do { \
198 if (condition) \
199 break; \
200 __wait_event(wq, condition); \
201 } while (0)
202
203 #define __wait_event_timeout(wq, condition, ret) \
204 do { \
205 DEFINE_WAIT(__wait); \
206 \
207 for (;;) { \
208 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
209 if (condition) \
210 break; \
211 ret = schedule_timeout(ret); \
212 if (!ret) \
213 break; \
214 } \
215 finish_wait(&wq, &__wait); \
216 } while (0)
217
218 /**
219 * wait_event_timeout - sleep until a condition gets true or a timeout elapses
220 * @wq: the waitqueue to wait on
221 * @condition: a C expression for the event to wait for
222 * @timeout: timeout, in jiffies
223 *
224 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
225 * @condition evaluates to true. The @condition is checked each time
226 * the waitqueue @wq is woken up.
227 *
228 * wake_up() has to be called after changing any variable that could
229 * change the result of the wait condition.
230 *
231 * The function returns 0 if the @timeout elapsed, and the remaining
232 * jiffies if the condition evaluated to true before the timeout elapsed.
233 */
234 #define wait_event_timeout(wq, condition, timeout) \
235 ({ \
236 long __ret = timeout; \
237 if (!(condition)) \
238 __wait_event_timeout(wq, condition, __ret); \
239 __ret; \
240 })
241
242 #define __wait_event_interruptible(wq, condition, ret) \
243 do { \
244 DEFINE_WAIT(__wait); \
245 \
246 for (;;) { \
247 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
248 if (condition) \
249 break; \
250 if (!signal_pending(current)) { \
251 schedule(); \
252 continue; \
253 } \
254 ret = -ERESTARTSYS; \
255 break; \
256 } \
257 finish_wait(&wq, &__wait); \
258 } while (0)
259
260 /**
261 * wait_event_interruptible - sleep until a condition gets true
262 * @wq: the waitqueue to wait on
263 * @condition: a C expression for the event to wait for
264 *
265 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
266 * @condition evaluates to true or a signal is received.
267 * The @condition is checked each time the waitqueue @wq is woken up.
268 *
269 * wake_up() has to be called after changing any variable that could
270 * change the result of the wait condition.
271 *
272 * The function will return -ERESTARTSYS if it was interrupted by a
273 * signal and 0 if @condition evaluated to true.
274 */
275 #define wait_event_interruptible(wq, condition) \
276 ({ \
277 int __ret = 0; \
278 if (!(condition)) \
279 __wait_event_interruptible(wq, condition, __ret); \
280 __ret; \
281 })
282
283 #define __wait_event_interruptible_timeout(wq, condition, ret) \
284 do { \
285 DEFINE_WAIT(__wait); \
286 \
287 for (;;) { \
288 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
289 if (condition) \
290 break; \
291 if (!signal_pending(current)) { \
292 ret = schedule_timeout(ret); \
293 if (!ret) \
294 break; \
295 continue; \
296 } \
297 ret = -ERESTARTSYS; \
298 break; \
299 } \
300 finish_wait(&wq, &__wait); \
301 } while (0)
302
303 /**
304 * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
305 * @wq: the waitqueue to wait on
306 * @condition: a C expression for the event to wait for
307 * @timeout: timeout, in jiffies
308 *
309 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
310 * @condition evaluates to true or a signal is received.
311 * The @condition is checked each time 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 * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
317 * was interrupted by a signal, and the remaining jiffies otherwise
318 * if the condition evaluated to true before the timeout elapsed.
319 */
320 #define wait_event_interruptible_timeout(wq, condition, timeout) \
321 ({ \
322 long __ret = timeout; \
323 if (!(condition)) \
324 __wait_event_interruptible_timeout(wq, condition, __ret); \
325 __ret; \
326 })
327
328 #define __wait_event_interruptible_exclusive(wq, condition, ret) \
329 do { \
330 DEFINE_WAIT(__wait); \
331 \
332 for (;;) { \
333 prepare_to_wait_exclusive(&wq, &__wait, \
334 TASK_INTERRUPTIBLE); \
335 if (condition) { \
336 finish_wait(&wq, &__wait); \
337 break; \
338 } \
339 if (!signal_pending(current)) { \
340 schedule(); \
341 continue; \
342 } \
343 ret = -ERESTARTSYS; \
344 abort_exclusive_wait(&wq, &__wait, \
345 TASK_INTERRUPTIBLE, NULL); \
346 break; \
347 } \
348 } while (0)
349
350 #define wait_event_interruptible_exclusive(wq, condition) \
351 ({ \
352 int __ret = 0; \
353 if (!(condition)) \
354 __wait_event_interruptible_exclusive(wq, condition, __ret);\
355 __ret; \
356 })
357
358 #define __wait_event_killable(wq, condition, ret) \
359 do { \
360 DEFINE_WAIT(__wait); \
361 \
362 for (;;) { \
363 prepare_to_wait(&wq, &__wait, TASK_KILLABLE); \
364 if (condition) \
365 break; \
366 if (!fatal_signal_pending(current)) { \
367 schedule(); \
368 continue; \
369 } \
370 ret = -ERESTARTSYS; \
371 break; \
372 } \
373 finish_wait(&wq, &__wait); \
374 } while (0)
375
376 /**
377 * wait_event_killable - sleep until a condition gets true
378 * @wq: the waitqueue to wait on
379 * @condition: a C expression for the event to wait for
380 *
381 * The process is put to sleep (TASK_KILLABLE) until the
382 * @condition evaluates to true or a signal is received.
383 * The @condition is checked each time the waitqueue @wq is woken up.
384 *
385 * wake_up() has to be called after changing any variable that could
386 * change the result of the wait condition.
387 *
388 * The function will return -ERESTARTSYS if it was interrupted by a
389 * signal and 0 if @condition evaluated to true.
390 */
391 #define wait_event_killable(wq, condition) \
392 ({ \
393 int __ret = 0; \
394 if (!(condition)) \
395 __wait_event_killable(wq, condition, __ret); \
396 __ret; \
397 })
398
399 /*
400 * Must be called with the spinlock in the wait_queue_head_t held.
401 */
402 static inline void add_wait_queue_exclusive_locked(wait_queue_head_t *q,
403 wait_queue_t * wait)
404 {
405 wait->flags |= WQ_FLAG_EXCLUSIVE;
406 __add_wait_queue_tail(q, wait);
407 }
408
409 /*
410 * Must be called with the spinlock in the wait_queue_head_t held.
411 */
412 static inline void remove_wait_queue_locked(wait_queue_head_t *q,
413 wait_queue_t * wait)
414 {
415 __remove_wait_queue(q, wait);
416 }
417
418 /*
419 * These are the old interfaces to sleep waiting for an event.
420 * They are racy. DO NOT use them, use the wait_event* interfaces above.
421 * We plan to remove these interfaces.
422 */
423 extern void sleep_on(wait_queue_head_t *q);
424 extern long sleep_on_timeout(wait_queue_head_t *q,
425 signed long timeout);
426 extern void interruptible_sleep_on(wait_queue_head_t *q);
427 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
428 signed long timeout);
429
430 /*
431 * Waitqueues which are removed from the waitqueue_head at wakeup time
432 */
433 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
434 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
435 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
436 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
437 unsigned int mode, void *key);
438 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
439 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
440
441 #define DEFINE_WAIT_FUNC(name, function) \
442 wait_queue_t name = { \
443 .private = current, \
444 .func = function, \
445 .task_list = LIST_HEAD_INIT((name).task_list), \
446 }
447
448 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
449
450 #define DEFINE_WAIT_BIT(name, word, bit) \
451 struct wait_bit_queue name = { \
452 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \
453 .wait = { \
454 .private = current, \
455 .func = wake_bit_function, \
456 .task_list = \
457 LIST_HEAD_INIT((name).wait.task_list), \
458 }, \
459 }
460
461 #define init_wait(wait) \
462 do { \
463 (wait)->private = current; \
464 (wait)->func = autoremove_wake_function; \
465 INIT_LIST_HEAD(&(wait)->task_list); \
466 } while (0)
467
468 /**
469 * wait_on_bit - wait for a bit to be cleared
470 * @word: the word being waited on, a kernel virtual address
471 * @bit: the bit of the word being waited on
472 * @action: the function used to sleep, which may take special actions
473 * @mode: the task state to sleep in
474 *
475 * There is a standard hashed waitqueue table for generic use. This
476 * is the part of the hashtable's accessor API that waits on a bit.
477 * For instance, if one were to have waiters on a bitflag, one would
478 * call wait_on_bit() in threads waiting for the bit to clear.
479 * One uses wait_on_bit() where one is waiting for the bit to clear,
480 * but has no intention of setting it.
481 */
482 static inline int wait_on_bit(void *word, int bit,
483 int (*action)(void *), unsigned mode)
484 {
485 if (!test_bit(bit, word))
486 return 0;
487 return out_of_line_wait_on_bit(word, bit, action, mode);
488 }
489
490 /**
491 * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
492 * @word: the word being waited on, a kernel virtual address
493 * @bit: the bit of the word being waited on
494 * @action: the function used to sleep, which may take special actions
495 * @mode: the task state to sleep in
496 *
497 * There is a standard hashed waitqueue table for generic use. This
498 * is the part of the hashtable's accessor API that waits on a bit
499 * when one intends to set it, for instance, trying to lock bitflags.
500 * For instance, if one were to have waiters trying to set bitflag
501 * and waiting for it to clear before setting it, one would call
502 * wait_on_bit() in threads waiting to be able to set the bit.
503 * One uses wait_on_bit_lock() where one is waiting for the bit to
504 * clear with the intention of setting it, and when done, clearing it.
505 */
506 static inline int wait_on_bit_lock(void *word, int bit,
507 int (*action)(void *), unsigned mode)
508 {
509 if (!test_and_set_bit(bit, word))
510 return 0;
511 return out_of_line_wait_on_bit_lock(word, bit, action, mode);
512 }
513
514 #endif /* __KERNEL__ */
515
516 #endif
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