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/config.h>
  23 #include <linux/list.h>
  24 #include <linux/stddef.h>
  25 #include <linux/spinlock.h>
  26 #include <asm/system.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         struct task_struct * task;
  36         wait_queue_func_t func;
  37         struct list_head task_list;
  38 };
  39
  40 struct __wait_queue_head {
  41         spinlock_t lock;
  42         struct list_head task_list;
  43 };
  44 typedef struct __wait_queue_head wait_queue_head_t;
  45
  46
  47 /*
  48  * Macros for declaration and initialisaton of the datatypes
  49  */
  50
  51 #define __WAITQUEUE_INITIALIZER(name, tsk) {                            \
  52         .task           = tsk,                                          \
  53         .func           = default_wake_function,                        \
  54         .task_list      = { NULL, NULL } }
  55
  56 #define DECLARE_WAITQUEUE(name, tsk)                                    \
  57         wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
  58
  59 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                           \
  60         .lock           = SPIN_LOCK_UNLOCKED,                           \
  61         .task_list      = { &(name).task_list, &(name).task_list } }
  62
  63 #define DECLARE_WAIT_QUEUE_HEAD(name) \
  64         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
  65
  66 static inline void init_waitqueue_head(wait_queue_head_t *q)
  67 {
  68         q->lock = SPIN_LOCK_UNLOCKED;
  69         INIT_LIST_HEAD(&q->task_list);
  70 }
  71
  72 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
  73 {
  74         q->flags = 0;
  75         q->task = p;
  76         q->func = default_wake_function;
  77 }
  78
  79 static inline void init_waitqueue_func_entry(wait_queue_t *q,
  80                                         wait_queue_func_t func)
  81 {
  82         q->flags = 0;
  83         q->task = NULL;
  84         q->func = func;
  85 }
  86
  87 static inline int waitqueue_active(wait_queue_head_t *q)
  88 {
  89         return !list_empty(&q->task_list);
  90 }
  91
  92 /*
  93  * Used to distinguish between sync and async io wait context:
  94  * sync i/o typically specifies a NULL wait queue entry or a wait
  95  * queue entry bound to a task (current task) to wake up.
  96  * aio specifies a wait queue entry with an async notification
  97  * callback routine, not associated with any task.
  98  */
  99 #define is_sync_wait(wait)      (!(wait) || ((wait)->task))
 100
 101 extern void FASTCALL(add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
 102 extern void FASTCALL(add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t * wait));
 103 extern void FASTCALL(remove_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
 104
 105 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
 106 {
 107         list_add(&new->task_list, &head->task_list);
 108 }
 109
 110 /*
 111  * Used for wake-one threads:
 112  */
 113 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
 114                                                 wait_queue_t *new)
 115 {
 116         list_add_tail(&new->task_list, &head->task_list);
 117 }
 118
 119 static inline void __remove_wait_queue(wait_queue_head_t *head,
 120                                                         wait_queue_t *old)
 121 {
 122         list_del(&old->task_list);
 123 }
 124
 125 void FASTCALL(__wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key));
 126 extern void FASTCALL(__wake_up_locked(wait_queue_head_t *q, unsigned int mode));
 127 extern void FASTCALL(__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr));
 128
 129 #define wake_up(x)                      __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1, NULL)
 130 #define wake_up_nr(x, nr)               __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr, NULL)
 131 #define wake_up_all(x)                  __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 0, NULL)
 132 #define wake_up_all_sync(x)                     __wake_up_sync((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 0)
 133 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 134 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
 135 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
 136 #define wake_up_locked(x)               __wake_up_locked((x), TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE)
 137 #define wake_up_interruptible_sync(x)   __wake_up_sync((x),TASK_INTERRUPTIBLE, 1)
 138
 139 #define __wait_event(wq, condition)                                     \
 140 do {                                                                    \
 141         DEFINE_WAIT(__wait);                                            \
 142                                                                         \
 143         for (;;) {                                                      \
 144                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 145                 if (condition)                                          \
 146                         break;                                          \
 147                 schedule();                                             \
 148         }                                                               \
 149         finish_wait(&wq, &__wait);                                      \
 150 } while (0)
 151
 152 #define wait_event(wq, condition)                                       \
 153 do {                                                                    \
 154         if (condition)                                                  \
 155                 break;                                                  \
 156         __wait_event(wq, condition);                                    \
 157 } while (0)
 158
 159 #define __wait_event_timeout(wq, condition, ret)                        \
 160 do {                                                                    \
 161         DEFINE_WAIT(__wait);                                            \
 162                                                                         \
 163         for (;;) {                                                      \
 164                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 165                 if (condition)                                          \
 166                         break;                                          \
 167                 ret = schedule_timeout(ret);                            \
 168                 if (!ret)                                               \
 169                         break;                                          \
 170         }                                                               \
 171         finish_wait(&wq, &__wait);                                      \
 172 } while (0)
 173
 174 #define wait_event_timeout(wq, condition, timeout)                      \
 175 ({                                                                      \
 176         long __ret = timeout;                                           \
 177         if (!(condition))                                               \
 178                 __wait_event_timeout(wq, condition, __ret);             \
 179         __ret;                                                          \
 180 })
 181
 182 #define __wait_event_interruptible(wq, condition, ret)                  \
 183 do {                                                                    \
 184         DEFINE_WAIT(__wait);                                            \
 185                                                                         \
 186         for (;;) {                                                      \
 187                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 188                 if (condition)                                          \
 189                         break;                                          \
 190                 if (!signal_pending(current)) {                         \
 191                         schedule();                                     \
 192                         continue;                                       \
 193                 }                                                       \
 194                 ret = -ERESTARTSYS;                                     \
 195                 break;                                                  \
 196         }                                                               \
 197         finish_wait(&wq, &__wait);                                      \
 198 } while (0)
 199
 200 #define wait_event_interruptible(wq, condition)                         \
 201 ({                                                                      \
 202         int __ret = 0;                                                  \
 203         if (!(condition))                                               \
 204                 __wait_event_interruptible(wq, condition, __ret);       \
 205         __ret;                                                          \
 206 })
 207
 208 #define __wait_event_interruptible_timeout(wq, condition, ret)          \
 209 do {                                                                    \
 210         DEFINE_WAIT(__wait);                                            \
 211                                                                         \
 212         for (;;) {                                                      \
 213                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 214                 if (condition)                                          \
 215                         break;                                          \
 216                 if (!signal_pending(current)) {                         \
 217                         ret = schedule_timeout(ret);                    \
 218                         if (!ret)                                       \
 219                                 break;                                  \
 220                         continue;                                       \
 221                 }                                                       \
 222                 ret = -ERESTARTSYS;                                     \
 223                 break;                                                  \
 224         }                                                               \
 225         finish_wait(&wq, &__wait);                                      \
 226 } while (0)
 227
 228 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
 229 ({                                                                      \
 230         long __ret = timeout;                                           \
 231         if (!(condition))                                               \
 232                 __wait_event_interruptible_timeout(wq, condition, __ret); \
 233         __ret;                                                          \
 234 })
 235
 236 #define __wait_event_interruptible_exclusive(wq, condition, ret)        \
 237 do {                                                                    \
 238         DEFINE_WAIT(__wait);                                            \
 239                                                                         \
 240         for (;;) {                                                      \
 241                 prepare_to_wait_exclusive(&wq, &__wait,                 \
 242                                         TASK_INTERRUPTIBLE);            \
 243                 if (condition)                                          \
 244                         break;                                          \
 245                 if (!signal_pending(current)) {                         \
 246                         schedule();                                     \
 247                         continue;                                       \
 248                 }                                                       \
 249                 ret = -ERESTARTSYS;                                     \
 250                 break;                                                  \
 251         }                                                               \
 252         finish_wait(&wq, &__wait);                                      \
 253 } while (0)
 254
 255 #define wait_event_interruptible_exclusive(wq, condition)               \
 256 ({                                                                      \
 257         int __ret = 0;                                                  \
 258         if (!(condition))                                               \
 259                 __wait_event_interruptible_exclusive(wq, condition, __ret);\
 260         __ret;                                                          \
 261 })
 262
 263 /*
 264  * Must be called with the spinlock in the wait_queue_head_t held.
 265  */
 266 static inline void add_wait_queue_exclusive_locked(wait_queue_head_t *q,
 267                                                    wait_queue_t * wait)
 268 {
 269         wait->flags |= WQ_FLAG_EXCLUSIVE;
 270         __add_wait_queue_tail(q,  wait);
 271 }
 272
 273 /*
 274  * Must be called with the spinlock in the wait_queue_head_t held.
 275  */
 276 static inline void remove_wait_queue_locked(wait_queue_head_t *q,
 277                                             wait_queue_t * wait)
 278 {
 279         __remove_wait_queue(q,  wait);
 280 }
 281
 282 /*
 283  * These are the old interfaces to sleep waiting for an event.
 284  * They are racy.  DO NOT use them, use the wait_event* interfaces above.
 285  * We plan to remove these interfaces during 2.7.
 286  */
 287 extern void FASTCALL(sleep_on(wait_queue_head_t *q));
 288 extern long FASTCALL(sleep_on_timeout(wait_queue_head_t *q,
 289                                       signed long timeout));
 290 extern void FASTCALL(interruptible_sleep_on(wait_queue_head_t *q));
 291 extern long FASTCALL(interruptible_sleep_on_timeout(wait_queue_head_t *q,
 292                                                     signed long timeout));
 293
 294 /*
 295  * Waitqueues which are removed from the waitqueue_head at wakeup time
 296  */
 297 void FASTCALL(prepare_to_wait(wait_queue_head_t *q,
 298                                 wait_queue_t *wait, int state));
 299 void FASTCALL(prepare_to_wait_exclusive(wait_queue_head_t *q,
 300                                 wait_queue_t *wait, int state));
 301 void FASTCALL(finish_wait(wait_queue_head_t *q, wait_queue_t *wait));
 302 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 303
 304 #define DEFINE_WAIT(name)                                               \
 305         wait_queue_t name = {                                           \
 306                 .task           = current,                              \
 307                 .func           = autoremove_wake_function,             \
 308                 .task_list      = {     .next = &name.task_list,        \
 309                                         .prev = &name.task_list,        \
 310                                 },                                      \
 311         }
 312
 313 #define init_wait(wait)                                                 \
 314         do {                                                            \
 315                 wait->task = current;                                   \
 316                 wait->func = autoremove_wake_function;                  \
 317                 INIT_LIST_HEAD(&wait->task_list);                       \
 318         } while (0)
 319
 320 #endif /* __KERNEL__ */
 321
 322 #endif