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 #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         struct task_struct * task;
  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
  58 /*
  59  * Macros for declaration and initialisaton of the datatypes
  60  */
  61
  62 #define __WAITQUEUE_INITIALIZER(name, tsk) {                            \
  63         .task           = 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,                           \
  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 static inline void init_waitqueue_head(wait_queue_head_t *q)
  81 {
  82         q->lock = SPIN_LOCK_UNLOCKED;
  83         INIT_LIST_HEAD(&q->task_list);
  84 }
  85
  86 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
  87 {
  88         q->flags = 0;
  89         q->task = p;
  90         q->func = default_wake_function;
  91 }
  92
  93 static inline void init_waitqueue_func_entry(wait_queue_t *q,
  94                                         wait_queue_func_t func)
  95 {
  96         q->flags = 0;
  97         q->task = NULL;
  98         q->func = func;
  99 }
 100
 101 static inline int waitqueue_active(wait_queue_head_t *q)
 102 {
 103         return !list_empty(&q->task_list);
 104 }
 105
 106 /*
 107  * Used to distinguish between sync and async io wait context:
 108  * sync i/o typically specifies a NULL wait queue entry or a wait
 109  * queue entry bound to a task (current task) to wake up.
 110  * aio specifies a wait queue entry with an async notification
 111  * callback routine, not associated with any task.
 112  */
 113 #define is_sync_wait(wait)      (!(wait) || ((wait)->task))
 114
 115 extern void FASTCALL(add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
 116 extern void FASTCALL(add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t * wait));
 117 extern void FASTCALL(remove_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
 118
 119 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
 120 {
 121         list_add(&new->task_list, &head->task_list);
 122 }
 123
 124 /*
 125  * Used for wake-one threads:
 126  */
 127 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
 128                                                 wait_queue_t *new)
 129 {
 130         list_add_tail(&new->task_list, &head->task_list);
 131 }
 132
 133 static inline void __remove_wait_queue(wait_queue_head_t *head,
 134                                                         wait_queue_t *old)
 135 {
 136         list_del(&old->task_list);
 137 }
 138
 139 void FASTCALL(__wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key));
 140 extern void FASTCALL(__wake_up_locked(wait_queue_head_t *q, unsigned int mode));
 141 extern void FASTCALL(__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr));
 142 void FASTCALL(__wake_up_bit(wait_queue_head_t *, void *, int));
 143 int FASTCALL(__wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned));
 144 int FASTCALL(__wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned));
 145 void FASTCALL(wake_up_bit(void *, int));
 146 int FASTCALL(out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned));
 147 int FASTCALL(out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned));
 148 wait_queue_head_t *FASTCALL(bit_waitqueue(void *, int));
 149
 150 #define wake_up(x)                      __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1, NULL)
 151 #define wake_up_nr(x, nr)               __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr, NULL)
 152 #define wake_up_all(x)                  __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 0, NULL)
 153 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 154 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
 155 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
 156 #define wake_up_locked(x)               __wake_up_locked((x), TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE)
 157 #define wake_up_interruptible_sync(x)   __wake_up_sync((x),TASK_INTERRUPTIBLE, 1)
 158
 159 #define __wait_event(wq, condition)                                     \
 160 do {                                                                    \
 161         DEFINE_WAIT(__wait);                                            \
 162                                                                         \
 163         for (;;) {                                                      \
 164                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 165                 if (condition)                                          \
 166                         break;                                          \
 167                 schedule();                                             \
 168         }                                                               \
 169         finish_wait(&wq, &__wait);                                      \
 170 } while (0)
 171
 172 #define wait_event(wq, condition)                                       \
 173 do {                                                                    \
 174         if (condition)                                                  \
 175                 break;                                                  \
 176         __wait_event(wq, condition);                                    \
 177 } while (0)
 178
 179 #define __wait_event_timeout(wq, condition, ret)                        \
 180 do {                                                                    \
 181         DEFINE_WAIT(__wait);                                            \
 182                                                                         \
 183         for (;;) {                                                      \
 184                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 185                 if (condition)                                          \
 186                         break;                                          \
 187                 ret = schedule_timeout(ret);                            \
 188                 if (!ret)                                               \
 189                         break;                                          \
 190         }                                                               \
 191         finish_wait(&wq, &__wait);                                      \
 192 } while (0)
 193
 194 #define wait_event_timeout(wq, condition, timeout)                      \
 195 ({                                                                      \
 196         long __ret = timeout;                                           \
 197         if (!(condition))                                               \
 198                 __wait_event_timeout(wq, condition, __ret);             \
 199         __ret;                                                          \
 200 })
 201
 202 #define __wait_event_interruptible(wq, condition, ret)                  \
 203 do {                                                                    \
 204         DEFINE_WAIT(__wait);                                            \
 205                                                                         \
 206         for (;;) {                                                      \
 207                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 208                 if (condition)                                          \
 209                         break;                                          \
 210                 if (!signal_pending(current)) {                         \
 211                         schedule();                                     \
 212                         continue;                                       \
 213                 }                                                       \
 214                 ret = -ERESTARTSYS;                                     \
 215                 break;                                                  \
 216         }                                                               \
 217         finish_wait(&wq, &__wait);                                      \
 218 } while (0)
 219
 220 #define wait_event_interruptible(wq, condition)                         \
 221 ({                                                                      \
 222         int __ret = 0;                                                  \
 223         if (!(condition))                                               \
 224                 __wait_event_interruptible(wq, condition, __ret);       \
 225         __ret;                                                          \
 226 })
 227
 228 #define __wait_event_interruptible_timeout(wq, condition, ret)          \
 229 do {                                                                    \
 230         DEFINE_WAIT(__wait);                                            \
 231                                                                         \
 232         for (;;) {                                                      \
 233                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 234                 if (condition)                                          \
 235                         break;                                          \
 236                 if (!signal_pending(current)) {                         \
 237                         ret = schedule_timeout(ret);                    \
 238                         if (!ret)                                       \
 239                                 break;                                  \
 240                         continue;                                       \
 241                 }                                                       \
 242                 ret = -ERESTARTSYS;                                     \
 243                 break;                                                  \
 244         }                                                               \
 245         finish_wait(&wq, &__wait);                                      \
 246 } while (0)
 247
 248 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
 249 ({                                                                      \
 250         long __ret = timeout;                                           \
 251         if (!(condition))                                               \
 252                 __wait_event_interruptible_timeout(wq, condition, __ret); \
 253         __ret;                                                          \
 254 })
 255
 256 #define __wait_event_interruptible_exclusive(wq, condition, ret)        \
 257 do {                                                                    \
 258         DEFINE_WAIT(__wait);                                            \
 259                                                                         \
 260         for (;;) {                                                      \
 261                 prepare_to_wait_exclusive(&wq, &__wait,                 \
 262                                         TASK_INTERRUPTIBLE);            \
 263                 if (condition)                                          \
 264                         break;                                          \
 265                 if (!signal_pending(current)) {                         \
 266                         schedule();                                     \
 267                         continue;                                       \
 268                 }                                                       \
 269                 ret = -ERESTARTSYS;                                     \
 270                 break;                                                  \
 271         }                                                               \
 272         finish_wait(&wq, &__wait);                                      \
 273 } while (0)
 274
 275 #define wait_event_interruptible_exclusive(wq, condition)               \
 276 ({                                                                      \
 277         int __ret = 0;                                                  \
 278         if (!(condition))                                               \
 279                 __wait_event_interruptible_exclusive(wq, condition, __ret);\
 280         __ret;                                                          \
 281 })
 282
 283 /*
 284  * Must be called with the spinlock in the wait_queue_head_t held.
 285  */
 286 static inline void add_wait_queue_exclusive_locked(wait_queue_head_t *q,
 287                                                    wait_queue_t * wait)
 288 {
 289         wait->flags |= WQ_FLAG_EXCLUSIVE;
 290         __add_wait_queue_tail(q,  wait);
 291 }
 292
 293 /*
 294  * Must be called with the spinlock in the wait_queue_head_t held.
 295  */
 296 static inline void remove_wait_queue_locked(wait_queue_head_t *q,
 297                                             wait_queue_t * wait)
 298 {
 299         __remove_wait_queue(q,  wait);
 300 }
 301
 302 /*
 303  * These are the old interfaces to sleep waiting for an event.
 304  * They are racy.  DO NOT use them, use the wait_event* interfaces above.
 305  * We plan to remove these interfaces during 2.7.
 306  */
 307 extern void FASTCALL(sleep_on(wait_queue_head_t *q));
 308 extern long FASTCALL(sleep_on_timeout(wait_queue_head_t *q,
 309                                       signed long timeout));
 310 extern void FASTCALL(interruptible_sleep_on(wait_queue_head_t *q));
 311 extern long FASTCALL(interruptible_sleep_on_timeout(wait_queue_head_t *q,
 312                                                     signed long timeout));
 313
 314 /*
 315  * Waitqueues which are removed from the waitqueue_head at wakeup time
 316  */
 317 void FASTCALL(prepare_to_wait(wait_queue_head_t *q,
 318                                 wait_queue_t *wait, int state));
 319 void FASTCALL(prepare_to_wait_exclusive(wait_queue_head_t *q,
 320                                 wait_queue_t *wait, int state));
 321 void FASTCALL(finish_wait(wait_queue_head_t *q, wait_queue_t *wait));
 322 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 323 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 324
 325 #define DEFINE_WAIT(name)                                               \
 326         wait_queue_t name = {                                           \
 327                 .task           = current,                              \
 328                 .func           = autoremove_wake_function,             \
 329                 .task_list      = {     .next = &(name).task_list,      \
 330                                         .prev = &(name).task_list,      \
 331                                 },                                      \
 332         }
 333
 334 #define DEFINE_WAIT_BIT(name, word, bit)                                \
 335         struct wait_bit_queue name = {                                  \
 336                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
 337                 .wait   = {                                             \
 338                         .task           = current,                      \
 339                         .func           = wake_bit_function,            \
 340                         .task_list      =                               \
 341                                 LIST_HEAD_INIT((name).wait.task_list),  \
 342                 },                                                      \
 343         }
 344
 345 #define init_wait(wait)                                                 \
 346         do {                                                            \
 347                 (wait)->task = current;                                 \
 348                 (wait)->func = autoremove_wake_function;                \
 349                 INIT_LIST_HEAD(&(wait)->task_list);                     \
 350         } while (0)
 351
 352 /**
 353  * wait_on_bit - wait for a bit to be cleared
 354  * @word: the word being waited on, a kernel virtual address
 355  * @bit: the bit of the word being waited on
 356  * @action: the function used to sleep, which may take special actions
 357  * @mode: the task state to sleep in
 358  *
 359  * There is a standard hashed waitqueue table for generic use. This
 360  * is the part of the hashtable's accessor API that waits on a bit.
 361  * For instance, if one were to have waiters on a bitflag, one would
 362  * call wait_on_bit() in threads waiting for the bit to clear.
 363  * One uses wait_on_bit() where one is waiting for the bit to clear,
 364  * but has no intention of setting it.
 365  */
 366 static inline int wait_on_bit(void *word, int bit,
 367                                 int (*action)(void *), unsigned mode)
 368 {
 369         if (!test_bit(bit, word))
 370                 return 0;
 371         return out_of_line_wait_on_bit(word, bit, action, mode);
 372 }
 373
 374 /**
 375  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
 376  * @word: the word being waited on, a kernel virtual address
 377  * @bit: the bit of the word being waited on
 378  * @action: the function used to sleep, which may take special actions
 379  * @mode: the task state to sleep in
 380  *
 381  * There is a standard hashed waitqueue table for generic use. This
 382  * is the part of the hashtable's accessor API that waits on a bit
 383  * when one intends to set it, for instance, trying to lock bitflags.
 384  * For instance, if one were to have waiters trying to set bitflag
 385  * and waiting for it to clear before setting it, one would call
 386  * wait_on_bit() in threads waiting to be able to set the bit.
 387  * One uses wait_on_bit_lock() where one is waiting for the bit to
 388  * clear with the intention of setting it, and when done, clearing it.
 389  */
 390 static inline int wait_on_bit_lock(void *word, int bit,
 391                                 int (*action)(void *), unsigned mode)
 392 {
 393         if (!test_and_set_bit(bit, word))
 394                 return 0;
 395         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
 396 }
 397
 398 #endif /* __KERNEL__ */
 399
 400 #endif