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[PATCH] efs: Remove incorrect unlock_kernel from failure path in efs_symlink_readpage()
[linux-2.6.git] / include / linux / wait.h
blobb3b9048421d8489568d27f41ff1303e09ab51f37
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 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
83 {
84 q->flags = 0;
85 q->private = p;
86 q->func = default_wake_function;
87 }
88
89 static inline void init_waitqueue_func_entry(wait_queue_t *q,
90 wait_queue_func_t func)
91 {
92 q->flags = 0;
93 q->private = NULL;
94 q->func = func;
95 }
96
97 static inline int waitqueue_active(wait_queue_head_t *q)
98 {
99 return !list_empty(&q->task_list);
100 }
101
102 /*
103 * Used to distinguish between sync and async io wait context:
104 * sync i/o typically specifies a NULL wait queue entry or a wait
105 * queue entry bound to a task (current task) to wake up.
106 * aio specifies a wait queue entry with an async notification
107 * callback routine, not associated with any task.
108 */
109 #define is_sync_wait(wait) (!(wait) || ((wait)->private))
110
111 extern void FASTCALL(add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
112 extern void FASTCALL(add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t * wait));
113 extern void FASTCALL(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 FASTCALL(__wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key));
136 extern void FASTCALL(__wake_up_locked(wait_queue_head_t *q, unsigned int mode));
137 extern void FASTCALL(__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr));
138 void FASTCALL(__wake_up_bit(wait_queue_head_t *, void *, int));
139 int FASTCALL(__wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned));
140 int FASTCALL(__wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned));
141 void FASTCALL(wake_up_bit(void *, int));
142 int FASTCALL(out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned));
143 int FASTCALL(out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned));
144 wait_queue_head_t *FASTCALL(bit_waitqueue(void *, int));
145
146 #define wake_up(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1, NULL)
147 #define wake_up_nr(x, nr) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr, NULL)
148 #define wake_up_all(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 0, NULL)
149 #define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
150 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
151 #define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
152 #define wake_up_locked(x) __wake_up_locked((x), TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE)
153 #define wake_up_interruptible_sync(x) __wake_up_sync((x),TASK_INTERRUPTIBLE, 1)
154
155 #define __wait_event(wq, condition) \
156 do { \
157 DEFINE_WAIT(__wait); \
158 \
159 for (;;) { \
160 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
161 if (condition) \
162 break; \
163 schedule(); \
164 } \
165 finish_wait(&wq, &__wait); \
166 } while (0)
167
168 /**
169 * wait_event - sleep until a condition gets true
170 * @wq: the waitqueue to wait on
171 * @condition: a C expression for the event to wait for
172 *
173 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
174 * @condition evaluates to true. The @condition is checked each time
175 * the waitqueue @wq is woken up.
176 *
177 * wake_up() has to be called after changing any variable that could
178 * change the result of the wait condition.
179 */
180 #define wait_event(wq, condition) \
181 do { \
182 if (condition) \
183 break; \
184 __wait_event(wq, condition); \
185 } while (0)
186
187 #define __wait_event_timeout(wq, condition, ret) \
188 do { \
189 DEFINE_WAIT(__wait); \
190 \
191 for (;;) { \
192 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
193 if (condition) \
194 break; \
195 ret = schedule_timeout(ret); \
196 if (!ret) \
197 break; \
198 } \
199 finish_wait(&wq, &__wait); \
200 } while (0)
201
202 /**
203 * wait_event_timeout - sleep until a condition gets true or a timeout elapses
204 * @wq: the waitqueue to wait on
205 * @condition: a C expression for the event to wait for
206 * @timeout: timeout, in jiffies
207 *
208 * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
209 * @condition evaluates to true. The @condition is checked each time
210 * the waitqueue @wq is woken up.
211 *
212 * wake_up() has to be called after changing any variable that could
213 * change the result of the wait condition.
214 *
215 * The function returns 0 if the @timeout elapsed, and the remaining
216 * jiffies if the condition evaluated to true before the timeout elapsed.
217 */
218 #define wait_event_timeout(wq, condition, timeout) \
219 ({ \
220 long __ret = timeout; \
221 if (!(condition)) \
222 __wait_event_timeout(wq, condition, __ret); \
223 __ret; \
224 })
225
226 #define __wait_event_interruptible(wq, condition, ret) \
227 do { \
228 DEFINE_WAIT(__wait); \
229 \
230 for (;;) { \
231 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
232 if (condition) \
233 break; \
234 if (!signal_pending(current)) { \
235 schedule(); \
236 continue; \
237 } \
238 ret = -ERESTARTSYS; \
239 break; \
240 } \
241 finish_wait(&wq, &__wait); \
242 } while (0)
243
244 /**
245 * wait_event_interruptible - sleep until a condition gets true
246 * @wq: the waitqueue to wait on
247 * @condition: a C expression for the event to wait for
248 *
249 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
250 * @condition evaluates to true or a signal is received.
251 * The @condition is checked each time the waitqueue @wq is woken up.
252 *
253 * wake_up() has to be called after changing any variable that could
254 * change the result of the wait condition.
255 *
256 * The function will return -ERESTARTSYS if it was interrupted by a
257 * signal and 0 if @condition evaluated to true.
258 */
259 #define wait_event_interruptible(wq, condition) \
260 ({ \
261 int __ret = 0; \
262 if (!(condition)) \
263 __wait_event_interruptible(wq, condition, __ret); \
264 __ret; \
265 })
266
267 #define __wait_event_interruptible_timeout(wq, condition, ret) \
268 do { \
269 DEFINE_WAIT(__wait); \
270 \
271 for (;;) { \
272 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
273 if (condition) \
274 break; \
275 if (!signal_pending(current)) { \
276 ret = schedule_timeout(ret); \
277 if (!ret) \
278 break; \
279 continue; \
280 } \
281 ret = -ERESTARTSYS; \
282 break; \
283 } \
284 finish_wait(&wq, &__wait); \
285 } while (0)
286
287 /**
288 * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
289 * @wq: the waitqueue to wait on
290 * @condition: a C expression for the event to wait for
291 * @timeout: timeout, in jiffies
292 *
293 * The process is put to sleep (TASK_INTERRUPTIBLE) until the
294 * @condition evaluates to true or a signal is received.
295 * The @condition is checked each time the waitqueue @wq is woken up.
296 *
297 * wake_up() has to be called after changing any variable that could
298 * change the result of the wait condition.
299 *
300 * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
301 * was interrupted by a signal, and the remaining jiffies otherwise
302 * if the condition evaluated to true before the timeout elapsed.
303 */
304 #define wait_event_interruptible_timeout(wq, condition, timeout) \
305 ({ \
306 long __ret = timeout; \
307 if (!(condition)) \
308 __wait_event_interruptible_timeout(wq, condition, __ret); \
309 __ret; \
310 })
311
312 #define __wait_event_interruptible_exclusive(wq, condition, ret) \
313 do { \
314 DEFINE_WAIT(__wait); \
315 \
316 for (;;) { \
317 prepare_to_wait_exclusive(&wq, &__wait, \
318 TASK_INTERRUPTIBLE); \
319 if (condition) \
320 break; \
321 if (!signal_pending(current)) { \
322 schedule(); \
323 continue; \
324 } \
325 ret = -ERESTARTSYS; \
326 break; \
327 } \
328 finish_wait(&wq, &__wait); \
329 } while (0)
330
331 #define wait_event_interruptible_exclusive(wq, condition) \
332 ({ \
333 int __ret = 0; \
334 if (!(condition)) \
335 __wait_event_interruptible_exclusive(wq, condition, __ret);\
336 __ret; \
337 })
338
339 /*
340 * Must be called with the spinlock in the wait_queue_head_t held.
341 */
342 static inline void add_wait_queue_exclusive_locked(wait_queue_head_t *q,
343 wait_queue_t * wait)
344 {
345 wait->flags |= WQ_FLAG_EXCLUSIVE;
346 __add_wait_queue_tail(q, wait);
347 }
348
349 /*
350 * Must be called with the spinlock in the wait_queue_head_t held.
351 */
352 static inline void remove_wait_queue_locked(wait_queue_head_t *q,
353 wait_queue_t * wait)
354 {
355 __remove_wait_queue(q, wait);
356 }
357
358 /*
359 * These are the old interfaces to sleep waiting for an event.
360 * They are racy. DO NOT use them, use the wait_event* interfaces above.
361 * We plan to remove these interfaces during 2.7.
362 */
363 extern void FASTCALL(sleep_on(wait_queue_head_t *q));
364 extern long FASTCALL(sleep_on_timeout(wait_queue_head_t *q,
365 signed long timeout));
366 extern void FASTCALL(interruptible_sleep_on(wait_queue_head_t *q));
367 extern long FASTCALL(interruptible_sleep_on_timeout(wait_queue_head_t *q,
368 signed long timeout));
369
370 /*
371 * Waitqueues which are removed from the waitqueue_head at wakeup time
372 */
373 void FASTCALL(prepare_to_wait(wait_queue_head_t *q,
374 wait_queue_t *wait, int state));
375 void FASTCALL(prepare_to_wait_exclusive(wait_queue_head_t *q,
376 wait_queue_t *wait, int state));
377 void FASTCALL(finish_wait(wait_queue_head_t *q, wait_queue_t *wait));
378 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
379 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
380
381 #define DEFINE_WAIT(name) \
382 wait_queue_t name = { \
383 .private = current, \
384 .func = autoremove_wake_function, \
385 .task_list = LIST_HEAD_INIT((name).task_list), \
386 }
387
388 #define DEFINE_WAIT_BIT(name, word, bit) \
389 struct wait_bit_queue name = { \
390 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \
391 .wait = { \
392 .private = current, \
393 .func = wake_bit_function, \
394 .task_list = \
395 LIST_HEAD_INIT((name).wait.task_list), \
396 }, \
397 }
398
399 #define init_wait(wait) \
400 do { \
401 (wait)->private = current; \
402 (wait)->func = autoremove_wake_function; \
403 INIT_LIST_HEAD(&(wait)->task_list); \
404 } while (0)
405
406 /**
407 * wait_on_bit - wait for a bit to be cleared
408 * @word: the word being waited on, a kernel virtual address
409 * @bit: the bit of the word being waited on
410 * @action: the function used to sleep, which may take special actions
411 * @mode: the task state to sleep in
412 *
413 * There is a standard hashed waitqueue table for generic use. This
414 * is the part of the hashtable's accessor API that waits on a bit.
415 * For instance, if one were to have waiters on a bitflag, one would
416 * call wait_on_bit() in threads waiting for the bit to clear.
417 * One uses wait_on_bit() where one is waiting for the bit to clear,
418 * but has no intention of setting it.
419 */
420 static inline int wait_on_bit(void *word, int bit,
421 int (*action)(void *), unsigned mode)
422 {
423 if (!test_bit(bit, word))
424 return 0;
425 return out_of_line_wait_on_bit(word, bit, action, mode);
426 }
427
428 /**
429 * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
430 * @word: the word being waited on, a kernel virtual address
431 * @bit: the bit of the word being waited on
432 * @action: the function used to sleep, which may take special actions
433 * @mode: the task state to sleep in
434 *
435 * There is a standard hashed waitqueue table for generic use. This
436 * is the part of the hashtable's accessor API that waits on a bit
437 * when one intends to set it, for instance, trying to lock bitflags.
438 * For instance, if one were to have waiters trying to set bitflag
439 * and waiting for it to clear before setting it, one would call
440 * wait_on_bit() in threads waiting to be able to set the bit.
441 * One uses wait_on_bit_lock() where one is waiting for the bit to
442 * clear with the intention of setting it, and when done, clearing it.
443 */
444 static inline int wait_on_bit_lock(void *word, int bit,
445 int (*action)(void *), unsigned mode)
446 {
447 if (!test_and_set_bit(bit, word))
448 return 0;
449 return out_of_line_wait_on_bit_lock(word, bit, action, mode);
450 }
451
452 #endif /* __KERNEL__ */
453
454 #endif
Linus' kernel tree