794be7af58aeff2191059ab350b1b258ea597a03
[linux-2.6.git] / include / linux / wait.h
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 /*
81  * lockdep: we want one lock-class for all waitqueue locks.
82  */
83 extern struct lock_class_key waitqueue_lock_key;
84
85 static inline void init_waitqueue_head(wait_queue_head_t *q)
86 {
87         spin_lock_init(&q->lock);
88         lockdep_set_class(&q->lock, &waitqueue_lock_key);
89         INIT_LIST_HEAD(&q->task_list);
90 }
91
92 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
93 {
94         q->flags = 0;
95         q->private = p;
96         q->func = default_wake_function;
97 }
98
99 static inline void init_waitqueue_func_entry(wait_queue_t *q,
100                                         wait_queue_func_t func)
101 {
102         q->flags = 0;
103         q->private = NULL;
104         q->func = func;
105 }
106
107 static inline int waitqueue_active(wait_queue_head_t *q)
108 {
109         return !list_empty(&q->task_list);
110 }
111
112 /*
113  * Used to distinguish between sync and async io wait context:
114  * sync i/o typically specifies a NULL wait queue entry or a wait
115  * queue entry bound to a task (current task) to wake up.
116  * aio specifies a wait queue entry with an async notification
117  * callback routine, not associated with any task.
118  */
119 #define is_sync_wait(wait)      (!(wait) || ((wait)->private))
120
121 extern void FASTCALL(add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
122 extern void FASTCALL(add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t * wait));
123 extern void FASTCALL(remove_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
124
125 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
126 {
127         list_add(&new->task_list, &head->task_list);
128 }
129
130 /*
131  * Used for wake-one threads:
132  */
133 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
134                                                 wait_queue_t *new)
135 {
136         list_add_tail(&new->task_list, &head->task_list);
137 }
138
139 static inline void __remove_wait_queue(wait_queue_head_t *head,
140                                                         wait_queue_t *old)
141 {
142         list_del(&old->task_list);
143 }
144
145 void FASTCALL(__wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key));
146 extern void FASTCALL(__wake_up_locked(wait_queue_head_t *q, unsigned int mode));
147 extern void FASTCALL(__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr));
148 void FASTCALL(__wake_up_bit(wait_queue_head_t *, void *, int));
149 int FASTCALL(__wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned));
150 int FASTCALL(__wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned));
151 void FASTCALL(wake_up_bit(void *, int));
152 int FASTCALL(out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned));
153 int FASTCALL(out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned));
154 wait_queue_head_t *FASTCALL(bit_waitqueue(void *, int));
155
156 #define wake_up(x)                      __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1, NULL)
157 #define wake_up_nr(x, nr)               __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr, NULL)
158 #define wake_up_all(x)                  __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 0, NULL)
159 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
160 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
161 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
162 #define wake_up_locked(x)               __wake_up_locked((x), TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE)
163 #define wake_up_interruptible_sync(x)   __wake_up_sync((x),TASK_INTERRUPTIBLE, 1)
164
165 #define __wait_event(wq, condition)                                     \
166 do {                                                                    \
167         DEFINE_WAIT(__wait);                                            \
168                                                                         \
169         for (;;) {                                                      \
170                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
171                 if (condition)                                          \
172                         break;                                          \
173                 schedule();                                             \
174         }                                                               \
175         finish_wait(&wq, &__wait);                                      \
176 } while (0)
177
178 /**
179  * wait_event - sleep until a condition gets true
180  * @wq: the waitqueue to wait on
181  * @condition: a C expression for the event to wait for
182  *
183  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
184  * @condition evaluates to true. The @condition is checked each time
185  * the waitqueue @wq is woken up.
186  *
187  * wake_up() has to be called after changing any variable that could
188  * change the result of the wait condition.
189  */
190 #define wait_event(wq, condition)                                       \
191 do {                                                                    \
192         if (condition)                                                  \
193                 break;                                                  \
194         __wait_event(wq, condition);                                    \
195 } while (0)
196
197 #define __wait_event_timeout(wq, condition, ret)                        \
198 do {                                                                    \
199         DEFINE_WAIT(__wait);                                            \
200                                                                         \
201         for (;;) {                                                      \
202                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
203                 if (condition)                                          \
204                         break;                                          \
205                 ret = schedule_timeout(ret);                            \
206                 if (!ret)                                               \
207                         break;                                          \
208         }                                                               \
209         finish_wait(&wq, &__wait);                                      \
210 } while (0)
211
212 /**
213  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
214  * @wq: the waitqueue to wait on
215  * @condition: a C expression for the event to wait for
216  * @timeout: timeout, in jiffies
217  *
218  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
219  * @condition evaluates to true. The @condition is checked each time
220  * the waitqueue @wq is woken up.
221  *
222  * wake_up() has to be called after changing any variable that could
223  * change the result of the wait condition.
224  *
225  * The function returns 0 if the @timeout elapsed, and the remaining
226  * jiffies if the condition evaluated to true before the timeout elapsed.
227  */
228 #define wait_event_timeout(wq, condition, timeout)                      \
229 ({                                                                      \
230         long __ret = timeout;                                           \
231         if (!(condition))                                               \
232                 __wait_event_timeout(wq, condition, __ret);             \
233         __ret;                                                          \
234 })
235
236 #define __wait_event_interruptible(wq, condition, ret)                  \
237 do {                                                                    \
238         DEFINE_WAIT(__wait);                                            \
239                                                                         \
240         for (;;) {                                                      \
241                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
242                 if (condition)                                          \
243                         break;                                          \
244                 if (!signal_pending(current)) {                         \
245                         schedule();                                     \
246                         continue;                                       \
247                 }                                                       \
248                 ret = -ERESTARTSYS;                                     \
249                 break;                                                  \
250         }                                                               \
251         finish_wait(&wq, &__wait);                                      \
252 } while (0)
253
254 /**
255  * wait_event_interruptible - sleep until a condition gets true
256  * @wq: the waitqueue to wait on
257  * @condition: a C expression for the event to wait for
258  *
259  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
260  * @condition evaluates to true or a signal is received.
261  * The @condition is checked each time the waitqueue @wq is woken up.
262  *
263  * wake_up() has to be called after changing any variable that could
264  * change the result of the wait condition.
265  *
266  * The function will return -ERESTARTSYS if it was interrupted by a
267  * signal and 0 if @condition evaluated to true.
268  */
269 #define wait_event_interruptible(wq, condition)                         \
270 ({                                                                      \
271         int __ret = 0;                                                  \
272         if (!(condition))                                               \
273                 __wait_event_interruptible(wq, condition, __ret);       \
274         __ret;                                                          \
275 })
276
277 #define __wait_event_interruptible_timeout(wq, condition, ret)          \
278 do {                                                                    \
279         DEFINE_WAIT(__wait);                                            \
280                                                                         \
281         for (;;) {                                                      \
282                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
283                 if (condition)                                          \
284                         break;                                          \
285                 if (!signal_pending(current)) {                         \
286                         ret = schedule_timeout(ret);                    \
287                         if (!ret)                                       \
288                                 break;                                  \
289                         continue;                                       \
290                 }                                                       \
291                 ret = -ERESTARTSYS;                                     \
292                 break;                                                  \
293         }                                                               \
294         finish_wait(&wq, &__wait);                                      \
295 } while (0)
296
297 /**
298  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
299  * @wq: the waitqueue to wait on
300  * @condition: a C expression for the event to wait for
301  * @timeout: timeout, in jiffies
302  *
303  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
304  * @condition evaluates to true or a signal is received.
305  * The @condition is checked each time the waitqueue @wq is woken up.
306  *
307  * wake_up() has to be called after changing any variable that could
308  * change the result of the wait condition.
309  *
310  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
311  * was interrupted by a signal, and the remaining jiffies otherwise
312  * if the condition evaluated to true before the timeout elapsed.
313  */
314 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
315 ({                                                                      \
316         long __ret = timeout;                                           \
317         if (!(condition))                                               \
318                 __wait_event_interruptible_timeout(wq, condition, __ret); \
319         __ret;                                                          \
320 })
321
322 #define __wait_event_interruptible_exclusive(wq, condition, ret)        \
323 do {                                                                    \
324         DEFINE_WAIT(__wait);                                            \
325                                                                         \
326         for (;;) {                                                      \
327                 prepare_to_wait_exclusive(&wq, &__wait,                 \
328                                         TASK_INTERRUPTIBLE);            \
329                 if (condition)                                          \
330                         break;                                          \
331                 if (!signal_pending(current)) {                         \
332                         schedule();                                     \
333                         continue;                                       \
334                 }                                                       \
335                 ret = -ERESTARTSYS;                                     \
336                 break;                                                  \
337         }                                                               \
338         finish_wait(&wq, &__wait);                                      \
339 } while (0)
340
341 #define wait_event_interruptible_exclusive(wq, condition)               \
342 ({                                                                      \
343         int __ret = 0;                                                  \
344         if (!(condition))                                               \
345                 __wait_event_interruptible_exclusive(wq, condition, __ret);\
346         __ret;                                                          \
347 })
348
349 /*
350  * Must be called with the spinlock in the wait_queue_head_t held.
351  */
352 static inline void add_wait_queue_exclusive_locked(wait_queue_head_t *q,
353                                                    wait_queue_t * wait)
354 {
355         wait->flags |= WQ_FLAG_EXCLUSIVE;
356         __add_wait_queue_tail(q,  wait);
357 }
358
359 /*
360  * Must be called with the spinlock in the wait_queue_head_t held.
361  */
362 static inline void remove_wait_queue_locked(wait_queue_head_t *q,
363                                             wait_queue_t * wait)
364 {
365         __remove_wait_queue(q,  wait);
366 }
367
368 /*
369  * These are the old interfaces to sleep waiting for an event.
370  * They are racy.  DO NOT use them, use the wait_event* interfaces above.  
371  * We plan to remove these interfaces during 2.7.
372  */
373 extern void FASTCALL(sleep_on(wait_queue_head_t *q));
374 extern long FASTCALL(sleep_on_timeout(wait_queue_head_t *q,
375                                       signed long timeout));
376 extern void FASTCALL(interruptible_sleep_on(wait_queue_head_t *q));
377 extern long FASTCALL(interruptible_sleep_on_timeout(wait_queue_head_t *q,
378                                                     signed long timeout));
379
380 /*
381  * Waitqueues which are removed from the waitqueue_head at wakeup time
382  */
383 void FASTCALL(prepare_to_wait(wait_queue_head_t *q,
384                                 wait_queue_t *wait, int state));
385 void FASTCALL(prepare_to_wait_exclusive(wait_queue_head_t *q,
386                                 wait_queue_t *wait, int state));
387 void FASTCALL(finish_wait(wait_queue_head_t *q, wait_queue_t *wait));
388 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
389 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
390
391 #define DEFINE_WAIT(name)                                               \
392         wait_queue_t name = {                                           \
393                 .private        = current,                              \
394                 .func           = autoremove_wake_function,             \
395                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
396         }
397
398 #define DEFINE_WAIT_BIT(name, word, bit)                                \
399         struct wait_bit_queue name = {                                  \
400                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
401                 .wait   = {                                             \
402                         .private        = current,                      \
403                         .func           = wake_bit_function,            \
404                         .task_list      =                               \
405                                 LIST_HEAD_INIT((name).wait.task_list),  \
406                 },                                                      \
407         }
408
409 #define init_wait(wait)                                                 \
410         do {                                                            \
411                 (wait)->private = current;                              \
412                 (wait)->func = autoremove_wake_function;                \
413                 INIT_LIST_HEAD(&(wait)->task_list);                     \
414         } while (0)
415
416 /**
417  * wait_on_bit - wait for a bit to be cleared
418  * @word: the word being waited on, a kernel virtual address
419  * @bit: the bit of the word being waited on
420  * @action: the function used to sleep, which may take special actions
421  * @mode: the task state to sleep in
422  *
423  * There is a standard hashed waitqueue table for generic use. This
424  * is the part of the hashtable's accessor API that waits on a bit.
425  * For instance, if one were to have waiters on a bitflag, one would
426  * call wait_on_bit() in threads waiting for the bit to clear.
427  * One uses wait_on_bit() where one is waiting for the bit to clear,
428  * but has no intention of setting it.
429  */
430 static inline int wait_on_bit(void *word, int bit,
431                                 int (*action)(void *), unsigned mode)
432 {
433         if (!test_bit(bit, word))
434                 return 0;
435         return out_of_line_wait_on_bit(word, bit, action, mode);
436 }
437
438 /**
439  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
440  * @word: the word being waited on, a kernel virtual address
441  * @bit: the bit of the word being waited on
442  * @action: the function used to sleep, which may take special actions
443  * @mode: the task state to sleep in
444  *
445  * There is a standard hashed waitqueue table for generic use. This
446  * is the part of the hashtable's accessor API that waits on a bit
447  * when one intends to set it, for instance, trying to lock bitflags.
448  * For instance, if one were to have waiters trying to set bitflag
449  * and waiting for it to clear before setting it, one would call
450  * wait_on_bit() in threads waiting to be able to set the bit.
451  * One uses wait_on_bit_lock() where one is waiting for the bit to
452  * clear with the intention of setting it, and when done, clearing it.
453  */
454 static inline int wait_on_bit_lock(void *word, int bit,
455                                 int (*action)(void *), unsigned mode)
456 {
457         if (!test_and_set_bit(bit, word))
458                 return 0;
459         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
460 }
461         
462 #endif /* __KERNEL__ */
463
464 #endif