include/linux/wait.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_WAIT_H
   3 #define _LINUX_WAIT_H
   4 /*
   5  * Linux wait queue related types and methods
   6  */
   7 #include <linux/list.h>
   8 #include <linux/stddef.h>
   9 #include <linux/spinlock.h>
  10
  11 #include <asm/current.h>
  12 #include <uapi/linux/wait.h>
  13
  14 typedef struct wait_queue_entry wait_queue_entry_t;
  15
  16 typedef int (*wait_queue_func_t)(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key);
  17 int default_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key);
  18
  19 /* wait_queue_entry::flags */
  20 #define WQ_FLAG_EXCLUSIVE       0x01
  21 #define WQ_FLAG_WOKEN           0x02
  22 #define WQ_FLAG_BOOKMARK        0x04
  23
  24 /*
  25  * A single wait-queue entry structure:
  26  */
  27 struct wait_queue_entry {
  28         unsigned int            flags;
  29         void                    *private;
  30         wait_queue_func_t       func;
  31         struct list_head        entry;
  32 };
  33
  34 struct wait_queue_head {
  35         spinlock_t              lock;
  36         struct list_head        head;
  37 };
  38 typedef struct wait_queue_head wait_queue_head_t;
  39
  40 struct task_struct;
  41
  42 /*
  43  * Macros for declaration and initialisaton of the datatypes
  44  */
  45
  46 #define __WAITQUEUE_INITIALIZER(name, tsk) {                                    \
  47         .private        = tsk,                                                  \
  48         .func           = default_wake_function,                                \
  49         .entry          = { NULL, NULL } }
  50
  51 #define DECLARE_WAITQUEUE(name, tsk)                                            \
  52         struct wait_queue_entry name = __WAITQUEUE_INITIALIZER(name, tsk)
  53
  54 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                                   \
  55         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),                      \
  56         .head           = { &(name).head, &(name).head } }
  57
  58 #define DECLARE_WAIT_QUEUE_HEAD(name) \
  59         struct wait_queue_head name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
  60
  61 extern void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *);
  62
  63 #define init_waitqueue_head(wq_head)                                            \
  64         do {                                                                    \
  65                 static struct lock_class_key __key;                             \
  66                                                                                 \
  67                 __init_waitqueue_head((wq_head), #wq_head, &__key);             \
  68         } while (0)
  69
  70 #ifdef CONFIG_LOCKDEP
  71 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
  72         ({ init_waitqueue_head(&name); name; })
  73 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
  74         struct wait_queue_head name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
  75 #else
  76 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
  77 #endif
  78
  79 static inline void init_waitqueue_entry(struct wait_queue_entry *wq_entry, struct task_struct *p)
  80 {
  81         wq_entry->flags         = 0;
  82         wq_entry->private       = p;
  83         wq_entry->func          = default_wake_function;
  84 }
  85
  86 static inline void
  87 init_waitqueue_func_entry(struct wait_queue_entry *wq_entry, wait_queue_func_t func)
  88 {
  89         wq_entry->flags         = 0;
  90         wq_entry->private       = NULL;
  91         wq_entry->func          = func;
  92 }
  93
  94 /**
  95  * waitqueue_active -- locklessly test for waiters on the queue
  96  * @wq_head: the waitqueue to test for waiters
  97  *
  98  * returns true if the wait list is not empty
  99  *
 100  * NOTE: this function is lockless and requires care, incorrect usage _will_
 101  * lead to sporadic and non-obvious failure.
 102  *
 103  * Use either while holding wait_queue_head::lock or when used for wakeups
 104  * with an extra smp_mb() like::
 105  *
 106  *      CPU0 - waker                    CPU1 - waiter
 107  *
 108  *                                      for (;;) {
 109  *      @cond = true;                     prepare_to_wait(&wq_head, &wait, state);
 110  *      smp_mb();                         // smp_mb() from set_current_state()
 111  *      if (waitqueue_active(wq_head))         if (@cond)
 112  *        wake_up(wq_head);                      break;
 113  *                                        schedule();
 114  *                                      }
 115  *                                      finish_wait(&wq_head, &wait);
 116  *
 117  * Because without the explicit smp_mb() it's possible for the
 118  * waitqueue_active() load to get hoisted over the @cond store such that we'll
 119  * observe an empty wait list while the waiter might not observe @cond.
 120  *
 121  * Also note that this 'optimization' trades a spin_lock() for an smp_mb(),
 122  * which (when the lock is uncontended) are of roughly equal cost.
 123  */
 124 static inline int waitqueue_active(struct wait_queue_head *wq_head)
 125 {
 126         return !list_empty(&wq_head->head);
 127 }
 128
 129 /**
 130  * wq_has_sleeper - check if there are any waiting processes
 131  * @wq_head: wait queue head
 132  *
 133  * Returns true if wq_head has waiting processes
 134  *
 135  * Please refer to the comment for waitqueue_active.
 136  */
 137 static inline bool wq_has_sleeper(struct wait_queue_head *wq_head)
 138 {
 139         /*
 140          * We need to be sure we are in sync with the
 141          * add_wait_queue modifications to the wait queue.
 142          *
 143          * This memory barrier should be paired with one on the
 144          * waiting side.
 145          */
 146         smp_mb();
 147         return waitqueue_active(wq_head);
 148 }
 149
 150 extern void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
 151 extern void add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
 152 extern void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
 153
 154 static inline void __add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
 155 {
 156         list_add(&wq_entry->entry, &wq_head->head);
 157 }
 158
 159 /*
 160  * Used for wake-one threads:
 161  */
 162 static inline void
 163 __add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
 164 {
 165         wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
 166         __add_wait_queue(wq_head, wq_entry);
 167 }
 168
 169 static inline void __add_wait_queue_entry_tail(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
 170 {
 171         list_add_tail(&wq_entry->entry, &wq_head->head);
 172 }
 173
 174 static inline void
 175 __add_wait_queue_entry_tail_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
 176 {
 177         wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
 178         __add_wait_queue_entry_tail(wq_head, wq_entry);
 179 }
 180
 181 static inline void
 182 __remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
 183 {
 184         list_del(&wq_entry->entry);
 185 }
 186
 187 void __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
 188 void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
 189 void __wake_up_locked_key_bookmark(struct wait_queue_head *wq_head,
 190                 unsigned int mode, void *key, wait_queue_entry_t *bookmark);
 191 void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
 192 void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr);
 193 void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode, int nr);
 194
 195 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
 196 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
 197 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
 198 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL, 1)
 199 #define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)
 200
 201 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 202 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
 203 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
 204 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
 205
 206 /*
 207  * Wakeup macros to be used to report events to the targets.
 208  */
 209 #define poll_to_key(m) ((void *)(__force uintptr_t)(__poll_t)(m))
 210 #define key_to_poll(m) ((__force __poll_t)(uintptr_t)(void *)(m))
 211 #define wake_up_poll(x, m)                                                      \
 212         __wake_up(x, TASK_NORMAL, 1, poll_to_key(m))
 213 #define wake_up_locked_poll(x, m)                                               \
 214         __wake_up_locked_key((x), TASK_NORMAL, poll_to_key(m))
 215 #define wake_up_interruptible_poll(x, m)                                        \
 216         __wake_up(x, TASK_INTERRUPTIBLE, 1, poll_to_key(m))
 217 #define wake_up_interruptible_sync_poll(x, m)                                   \
 218         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, poll_to_key(m))
 219
 220 #define ___wait_cond_timeout(condition)                                         \
 221 ({                                                                              \
 222         bool __cond = (condition);                                              \
 223         if (__cond && !__ret)                                                   \
 224                 __ret = 1;                                                      \
 225         __cond || !__ret;                                                       \
 226 })
 227
 228 #define ___wait_is_interruptible(state)                                         \
 229         (!__builtin_constant_p(state) ||                                        \
 230                 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE)          \
 231
 232 extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags);
 233
 234 /*
 235  * The below macro ___wait_event() has an explicit shadow of the __ret
 236  * variable when used from the wait_event_*() macros.
 237  *
 238  * This is so that both can use the ___wait_cond_timeout() construct
 239  * to wrap the condition.
 240  *
 241  * The type inconsistency of the wait_event_*() __ret variable is also
 242  * on purpose; we use long where we can return timeout values and int
 243  * otherwise.
 244  */
 245
 246 #define ___wait_event(wq_head, condition, state, exclusive, ret, cmd)           \
 247 ({                                                                              \
 248         __label__ __out;                                                        \
 249         struct wait_queue_entry __wq_entry;                                     \
 250         long __ret = ret;       /* explicit shadow */                           \
 251                                                                                 \
 252         init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0);        \
 253         for (;;) {                                                              \
 254                 long __int = prepare_to_wait_event(&wq_head, &__wq_entry, state);\
 255                                                                                 \
 256                 if (condition)                                                  \
 257                         break;                                                  \
 258                                                                                 \
 259                 if (___wait_is_interruptible(state) && __int) {                 \
 260                         __ret = __int;                                          \
 261                         goto __out;                                             \
 262                 }                                                               \
 263                                                                                 \
 264                 cmd;                                                            \
 265         }                                                                       \
 266         finish_wait(&wq_head, &__wq_entry);                                     \
 267 __out:  __ret;                                                                  \
 268 })
 269
 270 #define __wait_event(wq_head, condition)                                        \
 271         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
 272                             schedule())
 273
 274 /**
 275  * wait_event - sleep until a condition gets true
 276  * @wq_head: the waitqueue to wait on
 277  * @condition: a C expression for the event to wait for
 278  *
 279  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 280  * @condition evaluates to true. The @condition is checked each time
 281  * the waitqueue @wq_head is woken up.
 282  *
 283  * wake_up() has to be called after changing any variable that could
 284  * change the result of the wait condition.
 285  */
 286 #define wait_event(wq_head, condition)                                          \
 287 do {                                                                            \
 288         might_sleep();                                                          \
 289         if (condition)                                                          \
 290                 break;                                                          \
 291         __wait_event(wq_head, condition);                                       \
 292 } while (0)
 293
 294 #define __io_wait_event(wq_head, condition)                                     \
 295         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
 296                             io_schedule())
 297
 298 /*
 299  * io_wait_event() -- like wait_event() but with io_schedule()
 300  */
 301 #define io_wait_event(wq_head, condition)                                       \
 302 do {                                                                            \
 303         might_sleep();                                                          \
 304         if (condition)                                                          \
 305                 break;                                                          \
 306         __io_wait_event(wq_head, condition);                                    \
 307 } while (0)
 308
 309 #define __wait_event_freezable(wq_head, condition)                              \
 310         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
 311                             freezable_schedule())
 312
 313 /**
 314  * wait_event_freezable - sleep (or freeze) until a condition gets true
 315  * @wq_head: the waitqueue to wait on
 316  * @condition: a C expression for the event to wait for
 317  *
 318  * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
 319  * to system load) until the @condition evaluates to true. The
 320  * @condition is checked each time the waitqueue @wq_head is woken up.
 321  *
 322  * wake_up() has to be called after changing any variable that could
 323  * change the result of the wait condition.
 324  */
 325 #define wait_event_freezable(wq_head, condition)                                \
 326 ({                                                                              \
 327         int __ret = 0;                                                          \
 328         might_sleep();                                                          \
 329         if (!(condition))                                                       \
 330                 __ret = __wait_event_freezable(wq_head, condition);             \
 331         __ret;                                                                  \
 332 })
 333
 334 #define __wait_event_timeout(wq_head, condition, timeout)                       \
 335         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 336                       TASK_UNINTERRUPTIBLE, 0, timeout,                         \
 337                       __ret = schedule_timeout(__ret))
 338
 339 /**
 340  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 341  * @wq_head: the waitqueue to wait on
 342  * @condition: a C expression for the event to wait for
 343  * @timeout: timeout, in jiffies
 344  *
 345  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 346  * @condition evaluates to true. The @condition is checked each time
 347  * the waitqueue @wq_head is woken up.
 348  *
 349  * wake_up() has to be called after changing any variable that could
 350  * change the result of the wait condition.
 351  *
 352  * Returns:
 353  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 354  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 355  * or the remaining jiffies (at least 1) if the @condition evaluated
 356  * to %true before the @timeout elapsed.
 357  */
 358 #define wait_event_timeout(wq_head, condition, timeout)                         \
 359 ({                                                                              \
 360         long __ret = timeout;                                                   \
 361         might_sleep();                                                          \
 362         if (!___wait_cond_timeout(condition))                                   \
 363                 __ret = __wait_event_timeout(wq_head, condition, timeout);      \
 364         __ret;                                                                  \
 365 })
 366
 367 #define __wait_event_freezable_timeout(wq_head, condition, timeout)             \
 368         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 369                       TASK_INTERRUPTIBLE, 0, timeout,                           \
 370                       __ret = freezable_schedule_timeout(__ret))
 371
 372 /*
 373  * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
 374  * increasing load and is freezable.
 375  */
 376 #define wait_event_freezable_timeout(wq_head, condition, timeout)               \
 377 ({                                                                              \
 378         long __ret = timeout;                                                   \
 379         might_sleep();                                                          \
 380         if (!___wait_cond_timeout(condition))                                   \
 381                 __ret = __wait_event_freezable_timeout(wq_head, condition, timeout); \
 382         __ret;                                                                  \
 383 })
 384
 385 #define __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2)              \
 386         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 1, 0,     \
 387                             cmd1; schedule(); cmd2)
 388 /*
 389  * Just like wait_event_cmd(), except it sets exclusive flag
 390  */
 391 #define wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2)                \
 392 do {                                                                            \
 393         if (condition)                                                          \
 394                 break;                                                          \
 395         __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2);             \
 396 } while (0)
 397
 398 #define __wait_event_cmd(wq_head, condition, cmd1, cmd2)                        \
 399         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
 400                             cmd1; schedule(); cmd2)
 401
 402 /**
 403  * wait_event_cmd - sleep until a condition gets true
 404  * @wq_head: the waitqueue to wait on
 405  * @condition: a C expression for the event to wait for
 406  * @cmd1: the command will be executed before sleep
 407  * @cmd2: the command will be executed after sleep
 408  *
 409  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 410  * @condition evaluates to true. The @condition is checked each time
 411  * the waitqueue @wq_head is woken up.
 412  *
 413  * wake_up() has to be called after changing any variable that could
 414  * change the result of the wait condition.
 415  */
 416 #define wait_event_cmd(wq_head, condition, cmd1, cmd2)                          \
 417 do {                                                                            \
 418         if (condition)                                                          \
 419                 break;                                                          \
 420         __wait_event_cmd(wq_head, condition, cmd1, cmd2);                       \
 421 } while (0)
 422
 423 #define __wait_event_interruptible(wq_head, condition)                          \
 424         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
 425                       schedule())
 426
 427 /**
 428  * wait_event_interruptible - sleep until a condition gets true
 429  * @wq_head: the waitqueue to wait on
 430  * @condition: a C expression for the event to wait for
 431  *
 432  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 433  * @condition evaluates to true or a signal is received.
 434  * The @condition is checked each time the waitqueue @wq_head is woken up.
 435  *
 436  * wake_up() has to be called after changing any variable that could
 437  * change the result of the wait condition.
 438  *
 439  * The function will return -ERESTARTSYS if it was interrupted by a
 440  * signal and 0 if @condition evaluated to true.
 441  */
 442 #define wait_event_interruptible(wq_head, condition)                            \
 443 ({                                                                              \
 444         int __ret = 0;                                                          \
 445         might_sleep();                                                          \
 446         if (!(condition))                                                       \
 447                 __ret = __wait_event_interruptible(wq_head, condition);         \
 448         __ret;                                                                  \
 449 })
 450
 451 #define __wait_event_interruptible_timeout(wq_head, condition, timeout)         \
 452         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 453                       TASK_INTERRUPTIBLE, 0, timeout,                           \
 454                       __ret = schedule_timeout(__ret))
 455
 456 /**
 457  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 458  * @wq_head: the waitqueue to wait on
 459  * @condition: a C expression for the event to wait for
 460  * @timeout: timeout, in jiffies
 461  *
 462  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 463  * @condition evaluates to true or a signal is received.
 464  * The @condition is checked each time the waitqueue @wq_head is woken up.
 465  *
 466  * wake_up() has to be called after changing any variable that could
 467  * change the result of the wait condition.
 468  *
 469  * Returns:
 470  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 471  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 472  * the remaining jiffies (at least 1) if the @condition evaluated
 473  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
 474  * interrupted by a signal.
 475  */
 476 #define wait_event_interruptible_timeout(wq_head, condition, timeout)           \
 477 ({                                                                              \
 478         long __ret = timeout;                                                   \
 479         might_sleep();                                                          \
 480         if (!___wait_cond_timeout(condition))                                   \
 481                 __ret = __wait_event_interruptible_timeout(wq_head,             \
 482                                                 condition, timeout);            \
 483         __ret;                                                                  \
 484 })
 485
 486 #define __wait_event_hrtimeout(wq_head, condition, timeout, state)              \
 487 ({                                                                              \
 488         int __ret = 0;                                                          \
 489         struct hrtimer_sleeper __t;                                             \
 490                                                                                 \
 491         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);   \
 492         hrtimer_init_sleeper(&__t, current);                                    \
 493         if ((timeout) != KTIME_MAX)                                             \
 494                 hrtimer_start_range_ns(&__t.timer, timeout,                     \
 495                                        current->timer_slack_ns,                 \
 496                                        HRTIMER_MODE_REL);                       \
 497                                                                                 \
 498         __ret = ___wait_event(wq_head, condition, state, 0, 0,                  \
 499                 if (!__t.task) {                                                \
 500                         __ret = -ETIME;                                         \
 501                         break;                                                  \
 502                 }                                                               \
 503                 schedule());                                                    \
 504                                                                                 \
 505         hrtimer_cancel(&__t.timer);                                             \
 506         destroy_hrtimer_on_stack(&__t.timer);                                   \
 507         __ret;                                                                  \
 508 })
 509
 510 /**
 511  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
 512  * @wq_head: the waitqueue to wait on
 513  * @condition: a C expression for the event to wait for
 514  * @timeout: timeout, as a ktime_t
 515  *
 516  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 517  * @condition evaluates to true or a signal is received.
 518  * The @condition is checked each time the waitqueue @wq_head is woken up.
 519  *
 520  * wake_up() has to be called after changing any variable that could
 521  * change the result of the wait condition.
 522  *
 523  * The function returns 0 if @condition became true, or -ETIME if the timeout
 524  * elapsed.
 525  */
 526 #define wait_event_hrtimeout(wq_head, condition, timeout)                       \
 527 ({                                                                              \
 528         int __ret = 0;                                                          \
 529         might_sleep();                                                          \
 530         if (!(condition))                                                       \
 531                 __ret = __wait_event_hrtimeout(wq_head, condition, timeout,     \
 532                                                TASK_UNINTERRUPTIBLE);           \
 533         __ret;                                                                  \
 534 })
 535
 536 /**
 537  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
 538  * @wq: the waitqueue to wait on
 539  * @condition: a C expression for the event to wait for
 540  * @timeout: timeout, as a ktime_t
 541  *
 542  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 543  * @condition evaluates to true or a signal is received.
 544  * The @condition is checked each time the waitqueue @wq is woken up.
 545  *
 546  * wake_up() has to be called after changing any variable that could
 547  * change the result of the wait condition.
 548  *
 549  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
 550  * interrupted by a signal, or -ETIME if the timeout elapsed.
 551  */
 552 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)              \
 553 ({                                                                              \
 554         long __ret = 0;                                                         \
 555         might_sleep();                                                          \
 556         if (!(condition))                                                       \
 557                 __ret = __wait_event_hrtimeout(wq, condition, timeout,          \
 558                                                TASK_INTERRUPTIBLE);             \
 559         __ret;                                                                  \
 560 })
 561
 562 #define __wait_event_interruptible_exclusive(wq, condition)                     \
 563         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,                  \
 564                       schedule())
 565
 566 #define wait_event_interruptible_exclusive(wq, condition)                       \
 567 ({                                                                              \
 568         int __ret = 0;                                                          \
 569         might_sleep();                                                          \
 570         if (!(condition))                                                       \
 571                 __ret = __wait_event_interruptible_exclusive(wq, condition);    \
 572         __ret;                                                                  \
 573 })
 574
 575 #define __wait_event_killable_exclusive(wq, condition)                          \
 576         ___wait_event(wq, condition, TASK_KILLABLE, 1, 0,                       \
 577                       schedule())
 578
 579 #define wait_event_killable_exclusive(wq, condition)                            \
 580 ({                                                                              \
 581         int __ret = 0;                                                          \
 582         might_sleep();                                                          \
 583         if (!(condition))                                                       \
 584                 __ret = __wait_event_killable_exclusive(wq, condition);         \
 585         __ret;                                                                  \
 586 })
 587
 588
 589 #define __wait_event_freezable_exclusive(wq, condition)                         \
 590         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,                  \
 591                         freezable_schedule())
 592
 593 #define wait_event_freezable_exclusive(wq, condition)                           \
 594 ({                                                                              \
 595         int __ret = 0;                                                          \
 596         might_sleep();                                                          \
 597         if (!(condition))                                                       \
 598                 __ret = __wait_event_freezable_exclusive(wq, condition);        \
 599         __ret;                                                                  \
 600 })
 601
 602 /**
 603  * wait_event_idle - wait for a condition without contributing to system load
 604  * @wq_head: the waitqueue to wait on
 605  * @condition: a C expression for the event to wait for
 606  *
 607  * The process is put to sleep (TASK_IDLE) until the
 608  * @condition evaluates to true.
 609  * The @condition is checked each time the waitqueue @wq_head is woken up.
 610  *
 611  * wake_up() has to be called after changing any variable that could
 612  * change the result of the wait condition.
 613  *
 614  */
 615 #define wait_event_idle(wq_head, condition)                                     \
 616 do {                                                                            \
 617         might_sleep();                                                          \
 618         if (!(condition))                                                       \
 619                 ___wait_event(wq_head, condition, TASK_IDLE, 0, 0, schedule()); \
 620 } while (0)
 621
 622 /**
 623  * wait_event_idle_exclusive - wait for a condition with contributing to system load
 624  * @wq_head: the waitqueue to wait on
 625  * @condition: a C expression for the event to wait for
 626  *
 627  * The process is put to sleep (TASK_IDLE) until the
 628  * @condition evaluates to true.
 629  * The @condition is checked each time the waitqueue @wq_head is woken up.
 630  *
 631  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 632  * set thus if other processes wait on the same list, when this
 633  * process is woken further processes are not considered.
 634  *
 635  * wake_up() has to be called after changing any variable that could
 636  * change the result of the wait condition.
 637  *
 638  */
 639 #define wait_event_idle_exclusive(wq_head, condition)                           \
 640 do {                                                                            \
 641         might_sleep();                                                          \
 642         if (!(condition))                                                       \
 643                 ___wait_event(wq_head, condition, TASK_IDLE, 1, 0, schedule()); \
 644 } while (0)
 645
 646 #define __wait_event_idle_timeout(wq_head, condition, timeout)                  \
 647         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 648                       TASK_IDLE, 0, timeout,                                    \
 649                       __ret = schedule_timeout(__ret))
 650
 651 /**
 652  * wait_event_idle_timeout - sleep without load until a condition becomes true or a timeout elapses
 653  * @wq_head: the waitqueue to wait on
 654  * @condition: a C expression for the event to wait for
 655  * @timeout: timeout, in jiffies
 656  *
 657  * The process is put to sleep (TASK_IDLE) until the
 658  * @condition evaluates to true. The @condition is checked each time
 659  * the waitqueue @wq_head is woken up.
 660  *
 661  * wake_up() has to be called after changing any variable that could
 662  * change the result of the wait condition.
 663  *
 664  * Returns:
 665  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 666  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 667  * or the remaining jiffies (at least 1) if the @condition evaluated
 668  * to %true before the @timeout elapsed.
 669  */
 670 #define wait_event_idle_timeout(wq_head, condition, timeout)                    \
 671 ({                                                                              \
 672         long __ret = timeout;                                                   \
 673         might_sleep();                                                          \
 674         if (!___wait_cond_timeout(condition))                                   \
 675                 __ret = __wait_event_idle_timeout(wq_head, condition, timeout); \
 676         __ret;                                                                  \
 677 })
 678
 679 #define __wait_event_idle_exclusive_timeout(wq_head, condition, timeout)        \
 680         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 681                       TASK_IDLE, 1, timeout,                                    \
 682                       __ret = schedule_timeout(__ret))
 683
 684 /**
 685  * wait_event_idle_exclusive_timeout - sleep without load until a condition becomes true or a timeout elapses
 686  * @wq_head: the waitqueue to wait on
 687  * @condition: a C expression for the event to wait for
 688  * @timeout: timeout, in jiffies
 689  *
 690  * The process is put to sleep (TASK_IDLE) until the
 691  * @condition evaluates to true. The @condition is checked each time
 692  * the waitqueue @wq_head is woken up.
 693  *
 694  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 695  * set thus if other processes wait on the same list, when this
 696  * process is woken further processes are not considered.
 697  *
 698  * wake_up() has to be called after changing any variable that could
 699  * change the result of the wait condition.
 700  *
 701  * Returns:
 702  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 703  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 704  * or the remaining jiffies (at least 1) if the @condition evaluated
 705  * to %true before the @timeout elapsed.
 706  */
 707 #define wait_event_idle_exclusive_timeout(wq_head, condition, timeout)          \
 708 ({                                                                              \
 709         long __ret = timeout;                                                   \
 710         might_sleep();                                                          \
 711         if (!___wait_cond_timeout(condition))                                   \
 712                 __ret = __wait_event_idle_exclusive_timeout(wq_head, condition, timeout);\
 713         __ret;                                                                  \
 714 })
 715
 716 extern int do_wait_intr(wait_queue_head_t *, wait_queue_entry_t *);
 717 extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *);
 718
 719 #define __wait_event_interruptible_locked(wq, condition, exclusive, fn)         \
 720 ({                                                                              \
 721         int __ret;                                                              \
 722         DEFINE_WAIT(__wait);                                                    \
 723         if (exclusive)                                                          \
 724                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                              \
 725         do {                                                                    \
 726                 __ret = fn(&(wq), &__wait);                                     \
 727                 if (__ret)                                                      \
 728                         break;                                                  \
 729         } while (!(condition));                                                 \
 730         __remove_wait_queue(&(wq), &__wait);                                    \
 731         __set_current_state(TASK_RUNNING);                                      \
 732         __ret;                                                                  \
 733 })
 734
 735
 736 /**
 737  * wait_event_interruptible_locked - sleep until a condition gets true
 738  * @wq: the waitqueue to wait on
 739  * @condition: a C expression for the event to wait for
 740  *
 741  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 742  * @condition evaluates to true or a signal is received.
 743  * The @condition is checked each time the waitqueue @wq is woken up.
 744  *
 745  * It must be called with wq.lock being held.  This spinlock is
 746  * unlocked while sleeping but @condition testing is done while lock
 747  * is held and when this macro exits the lock is held.
 748  *
 749  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 750  * functions which must match the way they are locked/unlocked outside
 751  * of this macro.
 752  *
 753  * wake_up_locked() has to be called after changing any variable that could
 754  * change the result of the wait condition.
 755  *
 756  * The function will return -ERESTARTSYS if it was interrupted by a
 757  * signal and 0 if @condition evaluated to true.
 758  */
 759 #define wait_event_interruptible_locked(wq, condition)                          \
 760         ((condition)                                                            \
 761          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr))
 762
 763 /**
 764  * wait_event_interruptible_locked_irq - sleep until a condition gets true
 765  * @wq: the waitqueue to wait on
 766  * @condition: a C expression for the event to wait for
 767  *
 768  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 769  * @condition evaluates to true or a signal is received.
 770  * The @condition is checked each time the waitqueue @wq is woken up.
 771  *
 772  * It must be called with wq.lock being held.  This spinlock is
 773  * unlocked while sleeping but @condition testing is done while lock
 774  * is held and when this macro exits the lock is held.
 775  *
 776  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 777  * functions which must match the way they are locked/unlocked outside
 778  * of this macro.
 779  *
 780  * wake_up_locked() has to be called after changing any variable that could
 781  * change the result of the wait condition.
 782  *
 783  * The function will return -ERESTARTSYS if it was interrupted by a
 784  * signal and 0 if @condition evaluated to true.
 785  */
 786 #define wait_event_interruptible_locked_irq(wq, condition)                      \
 787         ((condition)                                                            \
 788          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr_irq))
 789
 790 /**
 791  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
 792  * @wq: the waitqueue to wait on
 793  * @condition: a C expression for the event to wait for
 794  *
 795  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 796  * @condition evaluates to true or a signal is received.
 797  * The @condition is checked each time the waitqueue @wq is woken up.
 798  *
 799  * It must be called with wq.lock being held.  This spinlock is
 800  * unlocked while sleeping but @condition testing is done while lock
 801  * is held and when this macro exits the lock is held.
 802  *
 803  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 804  * functions which must match the way they are locked/unlocked outside
 805  * of this macro.
 806  *
 807  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 808  * set thus when other process waits process on the list if this
 809  * process is awaken further processes are not considered.
 810  *
 811  * wake_up_locked() has to be called after changing any variable that could
 812  * change the result of the wait condition.
 813  *
 814  * The function will return -ERESTARTSYS if it was interrupted by a
 815  * signal and 0 if @condition evaluated to true.
 816  */
 817 #define wait_event_interruptible_exclusive_locked(wq, condition)                \
 818         ((condition)                                                            \
 819          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr))
 820
 821 /**
 822  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
 823  * @wq: the waitqueue to wait on
 824  * @condition: a C expression for the event to wait for
 825  *
 826  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 827  * @condition evaluates to true or a signal is received.
 828  * The @condition is checked each time the waitqueue @wq is woken up.
 829  *
 830  * It must be called with wq.lock being held.  This spinlock is
 831  * unlocked while sleeping but @condition testing is done while lock
 832  * is held and when this macro exits the lock is held.
 833  *
 834  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 835  * functions which must match the way they are locked/unlocked outside
 836  * of this macro.
 837  *
 838  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 839  * set thus when other process waits process on the list if this
 840  * process is awaken further processes are not considered.
 841  *
 842  * wake_up_locked() has to be called after changing any variable that could
 843  * change the result of the wait condition.
 844  *
 845  * The function will return -ERESTARTSYS if it was interrupted by a
 846  * signal and 0 if @condition evaluated to true.
 847  */
 848 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)            \
 849         ((condition)                                                            \
 850          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr_irq))
 851
 852
 853 #define __wait_event_killable(wq, condition)                                    \
 854         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
 855
 856 /**
 857  * wait_event_killable - sleep until a condition gets true
 858  * @wq_head: the waitqueue to wait on
 859  * @condition: a C expression for the event to wait for
 860  *
 861  * The process is put to sleep (TASK_KILLABLE) until the
 862  * @condition evaluates to true or a signal is received.
 863  * The @condition is checked each time the waitqueue @wq_head is woken up.
 864  *
 865  * wake_up() has to be called after changing any variable that could
 866  * change the result of the wait condition.
 867  *
 868  * The function will return -ERESTARTSYS if it was interrupted by a
 869  * signal and 0 if @condition evaluated to true.
 870  */
 871 #define wait_event_killable(wq_head, condition)                                 \
 872 ({                                                                              \
 873         int __ret = 0;                                                          \
 874         might_sleep();                                                          \
 875         if (!(condition))                                                       \
 876                 __ret = __wait_event_killable(wq_head, condition);              \
 877         __ret;                                                                  \
 878 })
 879
 880 #define __wait_event_killable_timeout(wq_head, condition, timeout)              \
 881         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 882                       TASK_KILLABLE, 0, timeout,                                \
 883                       __ret = schedule_timeout(__ret))
 884
 885 /**
 886  * wait_event_killable_timeout - sleep until a condition gets true or a timeout elapses
 887  * @wq_head: the waitqueue to wait on
 888  * @condition: a C expression for the event to wait for
 889  * @timeout: timeout, in jiffies
 890  *
 891  * The process is put to sleep (TASK_KILLABLE) until the
 892  * @condition evaluates to true or a kill signal is received.
 893  * The @condition is checked each time the waitqueue @wq_head is woken up.
 894  *
 895  * wake_up() has to be called after changing any variable that could
 896  * change the result of the wait condition.
 897  *
 898  * Returns:
 899  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 900  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 901  * the remaining jiffies (at least 1) if the @condition evaluated
 902  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
 903  * interrupted by a kill signal.
 904  *
 905  * Only kill signals interrupt this process.
 906  */
 907 #define wait_event_killable_timeout(wq_head, condition, timeout)                \
 908 ({                                                                              \
 909         long __ret = timeout;                                                   \
 910         might_sleep();                                                          \
 911         if (!___wait_cond_timeout(condition))                                   \
 912                 __ret = __wait_event_killable_timeout(wq_head,                  \
 913                                                 condition, timeout);            \
 914         __ret;                                                                  \
 915 })
 916
 917
 918 #define __wait_event_lock_irq(wq_head, condition, lock, cmd)                    \
 919         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
 920                             spin_unlock_irq(&lock);                             \
 921                             cmd;                                                \
 922                             schedule();                                         \
 923                             spin_lock_irq(&lock))
 924
 925 /**
 926  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
 927  *                           condition is checked under the lock. This
 928  *                           is expected to be called with the lock
 929  *                           taken.
 930  * @wq_head: the waitqueue to wait on
 931  * @condition: a C expression for the event to wait for
 932  * @lock: a locked spinlock_t, which will be released before cmd
 933  *        and schedule() and reacquired afterwards.
 934  * @cmd: a command which is invoked outside the critical section before
 935  *       sleep
 936  *
 937  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 938  * @condition evaluates to true. The @condition is checked each time
 939  * the waitqueue @wq_head is woken up.
 940  *
 941  * wake_up() has to be called after changing any variable that could
 942  * change the result of the wait condition.
 943  *
 944  * This is supposed to be called while holding the lock. The lock is
 945  * dropped before invoking the cmd and going to sleep and is reacquired
 946  * afterwards.
 947  */
 948 #define wait_event_lock_irq_cmd(wq_head, condition, lock, cmd)                  \
 949 do {                                                                            \
 950         if (condition)                                                          \
 951                 break;                                                          \
 952         __wait_event_lock_irq(wq_head, condition, lock, cmd);                   \
 953 } while (0)
 954
 955 /**
 956  * wait_event_lock_irq - sleep until a condition gets true. The
 957  *                       condition is checked under the lock. This
 958  *                       is expected to be called with the lock
 959  *                       taken.
 960  * @wq_head: the waitqueue to wait on
 961  * @condition: a C expression for the event to wait for
 962  * @lock: a locked spinlock_t, which will be released before schedule()
 963  *        and reacquired afterwards.
 964  *
 965  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 966  * @condition evaluates to true. The @condition is checked each time
 967  * the waitqueue @wq_head is woken up.
 968  *
 969  * wake_up() has to be called after changing any variable that could
 970  * change the result of the wait condition.
 971  *
 972  * This is supposed to be called while holding the lock. The lock is
 973  * dropped before going to sleep and is reacquired afterwards.
 974  */
 975 #define wait_event_lock_irq(wq_head, condition, lock)                           \
 976 do {                                                                            \
 977         if (condition)                                                          \
 978                 break;                                                          \
 979         __wait_event_lock_irq(wq_head, condition, lock, );                      \
 980 } while (0)
 981
 982
 983 #define __wait_event_interruptible_lock_irq(wq_head, condition, lock, cmd)      \
 984         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
 985                       spin_unlock_irq(&lock);                                   \
 986                       cmd;                                                      \
 987                       schedule();                                               \
 988                       spin_lock_irq(&lock))
 989
 990 /**
 991  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
 992  *              The condition is checked under the lock. This is expected to
 993  *              be called with the lock taken.
 994  * @wq_head: the waitqueue to wait on
 995  * @condition: a C expression for the event to wait for
 996  * @lock: a locked spinlock_t, which will be released before cmd and
 997  *        schedule() and reacquired afterwards.
 998  * @cmd: a command which is invoked outside the critical section before
 999  *       sleep
1000  *
1001  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1002  * @condition evaluates to true or a signal is received. The @condition is
1003  * checked each time the waitqueue @wq_head is woken up.
1004  *
1005  * wake_up() has to be called after changing any variable that could
1006  * change the result of the wait condition.
1007  *
1008  * This is supposed to be called while holding the lock. The lock is
1009  * dropped before invoking the cmd and going to sleep and is reacquired
1010  * afterwards.
1011  *
1012  * The macro will return -ERESTARTSYS if it was interrupted by a signal
1013  * and 0 if @condition evaluated to true.
1014  */
1015 #define wait_event_interruptible_lock_irq_cmd(wq_head, condition, lock, cmd)    \
1016 ({                                                                              \
1017         int __ret = 0;                                                          \
1018         if (!(condition))                                                       \
1019                 __ret = __wait_event_interruptible_lock_irq(wq_head,            \
1020                                                 condition, lock, cmd);          \
1021         __ret;                                                                  \
1022 })
1023
1024 /**
1025  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
1026  *              The condition is checked under the lock. This is expected
1027  *              to be called with the lock taken.
1028  * @wq_head: the waitqueue to wait on
1029  * @condition: a C expression for the event to wait for
1030  * @lock: a locked spinlock_t, which will be released before schedule()
1031  *        and reacquired afterwards.
1032  *
1033  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1034  * @condition evaluates to true or signal is received. The @condition is
1035  * checked each time the waitqueue @wq_head is woken up.
1036  *
1037  * wake_up() has to be called after changing any variable that could
1038  * change the result of the wait condition.
1039  *
1040  * This is supposed to be called while holding the lock. The lock is
1041  * dropped before going to sleep and is reacquired afterwards.
1042  *
1043  * The macro will return -ERESTARTSYS if it was interrupted by a signal
1044  * and 0 if @condition evaluated to true.
1045  */
1046 #define wait_event_interruptible_lock_irq(wq_head, condition, lock)             \
1047 ({                                                                              \
1048         int __ret = 0;                                                          \
1049         if (!(condition))                                                       \
1050                 __ret = __wait_event_interruptible_lock_irq(wq_head,            \
1051                                                 condition, lock,);              \
1052         __ret;                                                                  \
1053 })
1054
1055 #define __wait_event_lock_irq_timeout(wq_head, condition, lock, timeout, state) \
1056         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
1057                       state, 0, timeout,                                        \
1058                       spin_unlock_irq(&lock);                                   \
1059                       __ret = schedule_timeout(__ret);                          \
1060                       spin_lock_irq(&lock));
1061
1062 /**
1063  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
1064  *              true or a timeout elapses. The condition is checked under
1065  *              the lock. This is expected to be called with the lock taken.
1066  * @wq_head: the waitqueue to wait on
1067  * @condition: a C expression for the event to wait for
1068  * @lock: a locked spinlock_t, which will be released before schedule()
1069  *        and reacquired afterwards.
1070  * @timeout: timeout, in jiffies
1071  *
1072  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1073  * @condition evaluates to true or signal is received. The @condition is
1074  * checked each time the waitqueue @wq_head is woken up.
1075  *
1076  * wake_up() has to be called after changing any variable that could
1077  * change the result of the wait condition.
1078  *
1079  * This is supposed to be called while holding the lock. The lock is
1080  * dropped before going to sleep and is reacquired afterwards.
1081  *
1082  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
1083  * was interrupted by a signal, and the remaining jiffies otherwise
1084  * if the condition evaluated to true before the timeout elapsed.
1085  */
1086 #define wait_event_interruptible_lock_irq_timeout(wq_head, condition, lock,     \
1087                                                   timeout)                      \
1088 ({                                                                              \
1089         long __ret = timeout;                                                   \
1090         if (!___wait_cond_timeout(condition))                                   \
1091                 __ret = __wait_event_lock_irq_timeout(                          \
1092                                         wq_head, condition, lock, timeout,      \
1093                                         TASK_INTERRUPTIBLE);                    \
1094         __ret;                                                                  \
1095 })
1096
1097 #define wait_event_lock_irq_timeout(wq_head, condition, lock, timeout)          \
1098 ({                                                                              \
1099         long __ret = timeout;                                                   \
1100         if (!___wait_cond_timeout(condition))                                   \
1101                 __ret = __wait_event_lock_irq_timeout(                          \
1102                                         wq_head, condition, lock, timeout,      \
1103                                         TASK_UNINTERRUPTIBLE);                  \
1104         __ret;                                                                  \
1105 })
1106
1107 /*
1108  * Waitqueues which are removed from the waitqueue_head at wakeup time
1109  */
1110 void prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1111 void prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1112 long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1113 void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
1114 long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout);
1115 int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
1116 int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
1117
1118 #define DEFINE_WAIT_FUNC(name, function)                                        \
1119         struct wait_queue_entry name = {                                        \
1120                 .private        = current,                                      \
1121                 .func           = function,                                     \
1122                 .entry          = LIST_HEAD_INIT((name).entry),                 \
1123         }
1124
1125 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
1126
1127 #define init_wait(wait)                                                         \
1128         do {                                                                    \
1129                 (wait)->private = current;                                      \
1130                 (wait)->func = autoremove_wake_function;                        \
1131                 INIT_LIST_HEAD(&(wait)->entry);                                 \
1132                 (wait)->flags = 0;                                              \
1133         } while (0)
1134
1135 #endif /* _LINUX_WAIT_H */