LXR linux/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
  29typedef struct __wait_queue wait_queue_t;
  30typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int sync, void *key);
  31int default_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
  32
  33struct __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
  41struct wait_bit_key {
  42        void *flags;
  43        int bit_nr;
  44};
  45
  46struct wait_bit_queue {
  47        struct wait_bit_key key;
  48        wait_queue_t wait;
  49};
  50
  51struct __wait_queue_head {
  52        spinlock_t lock;
  53        struct list_head task_list;
  54};
  55typedef 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
  80static 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
  86static 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
  93static 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
 101static 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
 115extern void FASTCALL(add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
 116extern void FASTCALL(add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t * wait));
 117extern void FASTCALL(remove_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
 118
 119static 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 */
 127static 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
 133static inline void __remove_wait_queue(wait_queue_head_t *head,
 134                                                        wait_queue_t *old)
 135{
 136        list_del(&old->task_list);
 137}
 138
 139void FASTCALL(__wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key));
 140extern void FASTCALL(__wake_up_locked(wait_queue_head_t *q, unsigned int mode));
 141extern void FASTCALL(__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr));
 142void FASTCALL(__wake_up_bit(wait_queue_head_t *, void *, int));
 143int FASTCALL(__wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned));
 144int FASTCALL(__wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned));
 145void FASTCALL(wake_up_bit(void *, int));
 146int FASTCALL(out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned));
 147int FASTCALL(out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned));
 148wait_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)                                     \
 160do {                                                                    \
 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)                                       \
 173do {                                                                    \
 174        if (condition)                                                  \
 175                break;                                                  \
 176        __wait_event(wq, condition);                                    \
 177} while (0)
 178
 179#define __wait_event_timeout(wq, condition, ret)                        \
 180do {                                                                    \
 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)                  \
 203do {                                                                    \
 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)          \
 229do {                                                                    \
 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)        \
 257do {                                                                    \
 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 */
 286static 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 */
 296static 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 */
 307extern void FASTCALL(sleep_on(wait_queue_head_t *q));
 308extern long FASTCALL(sleep_on_timeout(wait_queue_head_t *q,
 309                                      signed long timeout));
 310extern void FASTCALL(interruptible_sleep_on(wait_queue_head_t *q));
 311extern 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 */
 317void FASTCALL(prepare_to_wait(wait_queue_head_t *q,
 318                                wait_queue_t *wait, int state));
 319void FASTCALL(prepare_to_wait_exclusive(wait_queue_head_t *q,
 320                                wait_queue_t *wait, int state));
 321void FASTCALL(finish_wait(wait_queue_head_t *q, wait_queue_t *wait));
 322int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 323int 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 */
 366static 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 */
 390static 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
 401