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 flags, void *key);
  30 int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, 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, struct lock_class_key *);
  81
  82 #define init_waitqueue_head(q)                          \
  83         do {                                            \
  84                 static struct lock_class_key __key;     \
  85                                                         \
  86                 __init_waitqueue_head((q), &__key);     \
  87         } while (0)
  88
  89 #ifdef CONFIG_LOCKDEP
  90 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
  91         ({ init_waitqueue_head(&name); name; })
  92 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
  93         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
  94 #else
  95 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
  96 #endif
  97
  98 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
  99 {
 100         q->flags = 0;
 101         q->private = p;
 102         q->func = default_wake_function;
 103 }
 104
 105 static inline void init_waitqueue_func_entry(wait_queue_t *q,
 106                                         wait_queue_func_t func)
 107 {
 108         q->flags = 0;
 109         q->private = NULL;
 110         q->func = func;
 111 }
 112
 113 static inline int waitqueue_active(wait_queue_head_t *q)
 114 {
 115         return !list_empty(&q->task_list);
 116 }
 117
 118 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 119 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
 120 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 121
 122 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
 123 {
 124         list_add(&new->task_list, &head->task_list);
 125 }
 126
 127 /*
 128  * Used for wake-one threads:
 129  */
 130 static inline void __add_wait_queue_exclusive(wait_queue_head_t *q,
 131                                               wait_queue_t *wait)
 132 {
 133         wait->flags |= WQ_FLAG_EXCLUSIVE;
 134         __add_wait_queue(q, wait);
 135 }
 136
 137 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
 138                                          wait_queue_t *new)
 139 {
 140         list_add_tail(&new->task_list, &head->task_list);
 141 }
 142
 143 static inline void __add_wait_queue_tail_exclusive(wait_queue_head_t *q,
 144                                               wait_queue_t *wait)
 145 {
 146         wait->flags |= WQ_FLAG_EXCLUSIVE;
 147         __add_wait_queue_tail(q, wait);
 148 }
 149
 150 static inline void __remove_wait_queue(wait_queue_head_t *head,
 151                                                         wait_queue_t *old)
 152 {
 153         list_del(&old->task_list);
 154 }
 155
 156 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 157 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
 158 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr,
 159                         void *key);
 160 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode);
 161 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
 162 void __wake_up_bit(wait_queue_head_t *, void *, int);
 163 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
 164 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
 165 void wake_up_bit(void *, int);
 166 int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned);
 167 int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned);
 168 wait_queue_head_t *bit_waitqueue(void *, int);
 169
 170 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
 171 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
 172 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
 173 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL)
 174
 175 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 176 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
 177 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
 178 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
 179
 180 /*
 181  * Wakeup macros to be used to report events to the targets.
 182  */
 183 #define wake_up_poll(x, m)                              \
 184         __wake_up(x, TASK_NORMAL, 1, (void *) (m))
 185 #define wake_up_locked_poll(x, m)                               \
 186         __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
 187 #define wake_up_interruptible_poll(x, m)                        \
 188         __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
 189 #define wake_up_interruptible_sync_poll(x, m)                           \
 190         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
 191
 192 #define __wait_event(wq, condition)                                     \
 193 do {                                                                    \
 194         DEFINE_WAIT(__wait);                                            \
 195                                                                         \
 196         for (;;) {                                                      \
 197                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 198                 if (condition)                                          \
 199                         break;                                          \
 200                 schedule();                                             \
 201         }                                                               \
 202         finish_wait(&wq, &__wait);                                      \
 203 } while (0)
 204
 205 /**
 206  * wait_event - sleep until a condition gets true
 207  * @wq: the waitqueue to wait on
 208  * @condition: a C expression for the event to wait for
 209  *
 210  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 211  * @condition evaluates to true. The @condition is checked each time
 212  * the waitqueue @wq is woken up.
 213  *
 214  * wake_up() has to be called after changing any variable that could
 215  * change the result of the wait condition.
 216  */
 217 #define wait_event(wq, condition)                                       \
 218 do {                                                                    \
 219         if (condition)                                                  \
 220                 break;                                                  \
 221         __wait_event(wq, condition);                                    \
 222 } while (0)
 223
 224 #define __wait_event_timeout(wq, condition, ret)                        \
 225 do {                                                                    \
 226         DEFINE_WAIT(__wait);                                            \
 227                                                                         \
 228         for (;;) {                                                      \
 229                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 230                 if (condition)                                          \
 231                         break;                                          \
 232                 ret = schedule_timeout(ret);                            \
 233                 if (!ret)                                               \
 234                         break;                                          \
 235         }                                                               \
 236         finish_wait(&wq, &__wait);                                      \
 237 } while (0)
 238
 239 /**
 240  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 241  * @wq: the waitqueue to wait on
 242  * @condition: a C expression for the event to wait for
 243  * @timeout: timeout, in jiffies
 244  *
 245  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 246  * @condition evaluates to true. The @condition is checked each time
 247  * the waitqueue @wq is woken up.
 248  *
 249  * wake_up() has to be called after changing any variable that could
 250  * change the result of the wait condition.
 251  *
 252  * The function returns 0 if the @timeout elapsed, and the remaining
 253  * jiffies if the condition evaluated to true before the timeout elapsed.
 254  */
 255 #define wait_event_timeout(wq, condition, timeout)                      \
 256 ({                                                                      \
 257         long __ret = timeout;                                           \
 258         if (!(condition))                                               \
 259                 __wait_event_timeout(wq, condition, __ret);             \
 260         __ret;                                                          \
 261 })
 262
 263 #define __wait_event_interruptible(wq, condition, ret)                  \
 264 do {                                                                    \
 265         DEFINE_WAIT(__wait);                                            \
 266                                                                         \
 267         for (;;) {                                                      \
 268                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 269                 if (condition)                                          \
 270                         break;                                          \
 271                 if (!signal_pending(current)) {                         \
 272                         schedule();                                     \
 273                         continue;                                       \
 274                 }                                                       \
 275                 ret = -ERESTARTSYS;                                     \
 276                 break;                                                  \
 277         }                                                               \
 278         finish_wait(&wq, &__wait);                                      \
 279 } while (0)
 280
 281 /**
 282  * wait_event_interruptible - sleep until a condition gets true
 283  * @wq: the waitqueue to wait on
 284  * @condition: a C expression for the event to wait for
 285  *
 286  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 287  * @condition evaluates to true or a signal is received.
 288  * The @condition is checked each time the waitqueue @wq is woken up.
 289  *
 290  * wake_up() has to be called after changing any variable that could
 291  * change the result of the wait condition.
 292  *
 293  * The function will return -ERESTARTSYS if it was interrupted by a
 294  * signal and 0 if @condition evaluated to true.
 295  */
 296 #define wait_event_interruptible(wq, condition)                         \
 297 ({                                                                      \
 298         int __ret = 0;                                                  \
 299         if (!(condition))                                               \
 300                 __wait_event_interruptible(wq, condition, __ret);       \
 301         __ret;                                                          \
 302 })
 303
 304 #define __wait_event_interruptible_timeout(wq, condition, ret)          \
 305 do {                                                                    \
 306         DEFINE_WAIT(__wait);                                            \
 307                                                                         \
 308         for (;;) {                                                      \
 309                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 310                 if (condition)                                          \
 311                         break;                                          \
 312                 if (!signal_pending(current)) {                         \
 313                         ret = schedule_timeout(ret);                    \
 314                         if (!ret)                                       \
 315                                 break;                                  \
 316                         continue;                                       \
 317                 }                                                       \
 318                 ret = -ERESTARTSYS;                                     \
 319                 break;                                                  \
 320         }                                                               \
 321         finish_wait(&wq, &__wait);                                      \
 322 } while (0)
 323
 324 /**
 325  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 326  * @wq: the waitqueue to wait on
 327  * @condition: a C expression for the event to wait for
 328  * @timeout: timeout, in jiffies
 329  *
 330  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 331  * @condition evaluates to true or a signal is received.
 332  * The @condition is checked each time the waitqueue @wq is woken up.
 333  *
 334  * wake_up() has to be called after changing any variable that could
 335  * change the result of the wait condition.
 336  *
 337  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
 338  * was interrupted by a signal, and the remaining jiffies otherwise
 339  * if the condition evaluated to true before the timeout elapsed.
 340  */
 341 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
 342 ({                                                                      \
 343         long __ret = timeout;                                           \
 344         if (!(condition))                                               \
 345                 __wait_event_interruptible_timeout(wq, condition, __ret); \
 346         __ret;                                                          \
 347 })
 348
 349 #define __wait_event_interruptible_exclusive(wq, condition, ret)        \
 350 do {                                                                    \
 351         DEFINE_WAIT(__wait);                                            \
 352                                                                         \
 353         for (;;) {                                                      \
 354                 prepare_to_wait_exclusive(&wq, &__wait,                 \
 355                                         TASK_INTERRUPTIBLE);            \
 356                 if (condition) {                                        \
 357                         finish_wait(&wq, &__wait);                      \
 358                         break;                                          \
 359                 }                                                       \
 360                 if (!signal_pending(current)) {                         \
 361                         schedule();                                     \
 362                         continue;                                       \
 363                 }                                                       \
 364                 ret = -ERESTARTSYS;                                     \
 365                 abort_exclusive_wait(&wq, &__wait,                      \
 366                                 TASK_INTERRUPTIBLE, NULL);              \
 367                 break;                                                  \
 368         }                                                               \
 369 } while (0)
 370
 371 #define wait_event_interruptible_exclusive(wq, condition)               \
 372 ({                                                                      \
 373         int __ret = 0;                                                  \
 374         if (!(condition))                                               \
 375                 __wait_event_interruptible_exclusive(wq, condition, __ret);\
 376         __ret;                                                          \
 377 })
 378
 379
 380 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
 381 ({                                                                      \
 382         int __ret = 0;                                                  \
 383         DEFINE_WAIT(__wait);                                            \
 384         if (exclusive)                                                  \
 385                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
 386         do {                                                            \
 387                 if (likely(list_empty(&__wait.task_list)))              \
 388                         __add_wait_queue_tail(&(wq), &__wait);          \
 389                 set_current_state(TASK_INTERRUPTIBLE);                  \
 390                 if (signal_pending(current)) {                          \
 391                         __ret = -ERESTARTSYS;                           \
 392                         break;                                          \
 393                 }                                                       \
 394                 if (irq)                                                \
 395                         spin_unlock_irq(&(wq).lock);                    \
 396                 else                                                    \
 397                         spin_unlock(&(wq).lock);                        \
 398                 schedule();                                             \
 399                 if (irq)                                                \
 400                         spin_lock_irq(&(wq).lock);                      \
 401                 else                                                    \
 402                         spin_lock(&(wq).lock);                          \
 403         } while (!(condition));                                         \
 404         __remove_wait_queue(&(wq), &__wait);                            \
 405         __set_current_state(TASK_RUNNING);                              \
 406         __ret;                                                          \
 407 })
 408
 409
 410 /**
 411  * wait_event_interruptible_locked - sleep until a condition gets true
 412  * @wq: the waitqueue to wait on
 413  * @condition: a C expression for the event to wait for
 414  *
 415  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 416  * @condition evaluates to true or a signal is received.
 417  * The @condition is checked each time the waitqueue @wq is woken up.
 418  *
 419  * It must be called with wq.lock being held.  This spinlock is
 420  * unlocked while sleeping but @condition testing is done while lock
 421  * is held and when this macro exits the lock is held.
 422  *
 423  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 424  * functions which must match the way they are locked/unlocked outside
 425  * of this macro.
 426  *
 427  * wake_up_locked() has to be called after changing any variable that could
 428  * change the result of the wait condition.
 429  *
 430  * The function will return -ERESTARTSYS if it was interrupted by a
 431  * signal and 0 if @condition evaluated to true.
 432  */
 433 #define wait_event_interruptible_locked(wq, condition)                  \
 434         ((condition)                                                    \
 435          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
 436
 437 /**
 438  * wait_event_interruptible_locked_irq - sleep until a condition gets true
 439  * @wq: the waitqueue to wait on
 440  * @condition: a C expression for the event to wait for
 441  *
 442  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 443  * @condition evaluates to true or a signal is received.
 444  * The @condition is checked each time the waitqueue @wq is woken up.
 445  *
 446  * It must be called with wq.lock being held.  This spinlock is
 447  * unlocked while sleeping but @condition testing is done while lock
 448  * is held and when this macro exits the lock is held.
 449  *
 450  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 451  * functions which must match the way they are locked/unlocked outside
 452  * of this macro.
 453  *
 454  * wake_up_locked() has to be called after changing any variable that could
 455  * change the result of the wait condition.
 456  *
 457  * The function will return -ERESTARTSYS if it was interrupted by a
 458  * signal and 0 if @condition evaluated to true.
 459  */
 460 #define wait_event_interruptible_locked_irq(wq, condition)              \
 461         ((condition)                                                    \
 462          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
 463
 464 /**
 465  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
 466  * @wq: the waitqueue to wait on
 467  * @condition: a C expression for the event to wait for
 468  *
 469  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 470  * @condition evaluates to true or a signal is received.
 471  * The @condition is checked each time the waitqueue @wq is woken up.
 472  *
 473  * It must be called with wq.lock being held.  This spinlock is
 474  * unlocked while sleeping but @condition testing is done while lock
 475  * is held and when this macro exits the lock is held.
 476  *
 477  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 478  * functions which must match the way they are locked/unlocked outside
 479  * of this macro.
 480  *
 481  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 482  * set thus when other process waits process on the list if this
 483  * process is awaken further processes are not considered.
 484  *
 485  * wake_up_locked() has to be called after changing any variable that could
 486  * change the result of the wait condition.
 487  *
 488  * The function will return -ERESTARTSYS if it was interrupted by a
 489  * signal and 0 if @condition evaluated to true.
 490  */
 491 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
 492         ((condition)                                                    \
 493          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
 494
 495 /**
 496  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
 497  * @wq: the waitqueue to wait on
 498  * @condition: a C expression for the event to wait for
 499  *
 500  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 501  * @condition evaluates to true or a signal is received.
 502  * The @condition is checked each time the waitqueue @wq is woken up.
 503  *
 504  * It must be called with wq.lock being held.  This spinlock is
 505  * unlocked while sleeping but @condition testing is done while lock
 506  * is held and when this macro exits the lock is held.
 507  *
 508  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 509  * functions which must match the way they are locked/unlocked outside
 510  * of this macro.
 511  *
 512  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 513  * set thus when other process waits process on the list if this
 514  * process is awaken further processes are not considered.
 515  *
 516  * wake_up_locked() has to be called after changing any variable that could
 517  * change the result of the wait condition.
 518  *
 519  * The function will return -ERESTARTSYS if it was interrupted by a
 520  * signal and 0 if @condition evaluated to true.
 521  */
 522 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
 523         ((condition)                                                    \
 524          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
 525
 526
 527
 528 #define __wait_event_killable(wq, condition, ret)                       \
 529 do {                                                                    \
 530         DEFINE_WAIT(__wait);                                            \
 531                                                                         \
 532         for (;;) {                                                      \
 533                 prepare_to_wait(&wq, &__wait, TASK_KILLABLE);           \
 534                 if (condition)                                          \
 535                         break;                                          \
 536                 if (!fatal_signal_pending(current)) {                   \
 537                         schedule();                                     \
 538                         continue;                                       \
 539                 }                                                       \
 540                 ret = -ERESTARTSYS;                                     \
 541                 break;                                                  \
 542         }                                                               \
 543         finish_wait(&wq, &__wait);                                      \
 544 } while (0)
 545
 546 /**
 547  * wait_event_killable - sleep until a condition gets true
 548  * @wq: the waitqueue to wait on
 549  * @condition: a C expression for the event to wait for
 550  *
 551  * The process is put to sleep (TASK_KILLABLE) until the
 552  * @condition evaluates to true or a signal is received.
 553  * The @condition is checked each time the waitqueue @wq is woken up.
 554  *
 555  * wake_up() has to be called after changing any variable that could
 556  * change the result of the wait condition.
 557  *
 558  * The function will return -ERESTARTSYS if it was interrupted by a
 559  * signal and 0 if @condition evaluated to true.
 560  */
 561 #define wait_event_killable(wq, condition)                              \
 562 ({                                                                      \
 563         int __ret = 0;                                                  \
 564         if (!(condition))                                               \
 565                 __wait_event_killable(wq, condition, __ret);            \
 566         __ret;                                                          \
 567 })
 568
 569 /*
 570  * These are the old interfaces to sleep waiting for an event.
 571  * They are racy.  DO NOT use them, use the wait_event* interfaces above.
 572  * We plan to remove these interfaces.
 573  */
 574 extern void sleep_on(wait_queue_head_t *q);
 575 extern long sleep_on_timeout(wait_queue_head_t *q,
 576                                       signed long timeout);
 577 extern void interruptible_sleep_on(wait_queue_head_t *q);
 578 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
 579                                            signed long timeout);
 580
 581 /*
 582  * Waitqueues which are removed from the waitqueue_head at wakeup time
 583  */
 584 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
 585 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
 586 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
 587 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
 588                         unsigned int mode, void *key);
 589 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 590 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 591
 592 #define DEFINE_WAIT_FUNC(name, function)                                \
 593         wait_queue_t name = {                                           \
 594                 .private        = current,                              \
 595                 .func           = function,                             \
 596                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
 597         }
 598
 599 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
 600
 601 #define DEFINE_WAIT_BIT(name, word, bit)                                \
 602         struct wait_bit_queue name = {                                  \
 603                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
 604                 .wait   = {                                             \
 605                         .private        = current,                      \
 606                         .func           = wake_bit_function,            \
 607                         .task_list      =                               \
 608                                 LIST_HEAD_INIT((name).wait.task_list),  \
 609                 },                                                      \
 610         }
 611
 612 #define init_wait(wait)                                                 \
 613         do {                                                            \
 614                 (wait)->private = current;                              \
 615                 (wait)->func = autoremove_wake_function;                \
 616                 INIT_LIST_HEAD(&(wait)->task_list);                     \
 617                 (wait)->flags = 0;                                      \
 618         } while (0)
 619
 620 /**
 621  * wait_on_bit - wait for a bit to be cleared
 622  * @word: the word being waited on, a kernel virtual address
 623  * @bit: the bit of the word being waited on
 624  * @action: the function used to sleep, which may take special actions
 625  * @mode: the task state to sleep in
 626  *
 627  * There is a standard hashed waitqueue table for generic use. This
 628  * is the part of the hashtable's accessor API that waits on a bit.
 629  * For instance, if one were to have waiters on a bitflag, one would
 630  * call wait_on_bit() in threads waiting for the bit to clear.
 631  * One uses wait_on_bit() where one is waiting for the bit to clear,
 632  * but has no intention of setting it.
 633  */
 634 static inline int wait_on_bit(void *word, int bit,
 635                                 int (*action)(void *), unsigned mode)
 636 {
 637         if (!test_bit(bit, word))
 638                 return 0;
 639         return out_of_line_wait_on_bit(word, bit, action, mode);
 640 }
 641
 642 /**
 643  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
 644  * @word: the word being waited on, a kernel virtual address
 645  * @bit: the bit of the word being waited on
 646  * @action: the function used to sleep, which may take special actions
 647  * @mode: the task state to sleep in
 648  *
 649  * There is a standard hashed waitqueue table for generic use. This
 650  * is the part of the hashtable's accessor API that waits on a bit
 651  * when one intends to set it, for instance, trying to lock bitflags.
 652  * For instance, if one were to have waiters trying to set bitflag
 653  * and waiting for it to clear before setting it, one would call
 654  * wait_on_bit() in threads waiting to be able to set the bit.
 655  * One uses wait_on_bit_lock() where one is waiting for the bit to
 656  * clear with the intention of setting it, and when done, clearing it.
 657  */
 658 static inline int wait_on_bit_lock(void *word, int bit,
 659                                 int (*action)(void *), unsigned mode)
 660 {
 661         if (!test_and_set_bit(bit, word))
 662                 return 0;
 663         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
 664 }
 665
 666 #endif /* __KERNEL__ */
 667
 668 #endif