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 void __wake_up_pollfree(struct wait_queue_head *wq_head);
 195
 196 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
 197 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
 198 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
 199 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL, 1)
 200 #define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)
 201
 202 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 203 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
 204 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
 205 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
 206
 207 /*
 208  * Wakeup macros to be used to report events to the targets.
 209  */
 210 #define poll_to_key(m) ((void *)(__force uintptr_t)(__poll_t)(m))
 211 #define key_to_poll(m) ((__force __poll_t)(uintptr_t)(void *)(m))
 212 #define wake_up_poll(x, m)                                                      \
 213         __wake_up(x, TASK_NORMAL, 1, poll_to_key(m))
 214 #define wake_up_locked_poll(x, m)                                               \
 215         __wake_up_locked_key((x), TASK_NORMAL, poll_to_key(m))
 216 #define wake_up_interruptible_poll(x, m)                                        \
 217         __wake_up(x, TASK_INTERRUPTIBLE, 1, poll_to_key(m))
 218 #define wake_up_interruptible_sync_poll(x, m)                                   \
 219         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, poll_to_key(m))
 220
 221 /**
 222  * wake_up_pollfree - signal that a polled waitqueue is going away
 223  * @wq_head: the wait queue head
 224  *
 225  * In the very rare cases where a ->poll() implementation uses a waitqueue whose
 226  * lifetime is tied to a task rather than to the 'struct file' being polled,
 227  * this function must be called before the waitqueue is freed so that
 228  * non-blocking polls (e.g. epoll) are notified that the queue is going away.
 229  *
 230  * The caller must also RCU-delay the freeing of the wait_queue_head, e.g. via
 231  * an explicit synchronize_rcu() or call_rcu(), or via SLAB_TYPESAFE_BY_RCU.
 232  */
 233 static inline void wake_up_pollfree(struct wait_queue_head *wq_head)
 234 {
 235         /*
 236          * For performance reasons, we don't always take the queue lock here.
 237          * Therefore, we might race with someone removing the last entry from
 238          * the queue, and proceed while they still hold the queue lock.
 239          * However, rcu_read_lock() is required to be held in such cases, so we
 240          * can safely proceed with an RCU-delayed free.
 241          */
 242         if (waitqueue_active(wq_head))
 243                 __wake_up_pollfree(wq_head);
 244 }
 245
 246 #define ___wait_cond_timeout(condition)                                         \
 247 ({                                                                              \
 248         bool __cond = (condition);                                              \
 249         if (__cond && !__ret)                                                   \
 250                 __ret = 1;                                                      \
 251         __cond || !__ret;                                                       \
 252 })
 253
 254 #define ___wait_is_interruptible(state)                                         \
 255         (!__builtin_constant_p(state) ||                                        \
 256                 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE)          \
 257
 258 extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags);
 259
 260 /*
 261  * The below macro ___wait_event() has an explicit shadow of the __ret
 262  * variable when used from the wait_event_*() macros.
 263  *
 264  * This is so that both can use the ___wait_cond_timeout() construct
 265  * to wrap the condition.
 266  *
 267  * The type inconsistency of the wait_event_*() __ret variable is also
 268  * on purpose; we use long where we can return timeout values and int
 269  * otherwise.
 270  */
 271
 272 #define ___wait_event(wq_head, condition, state, exclusive, ret, cmd)           \
 273 ({                                                                              \
 274         __label__ __out;                                                        \
 275         struct wait_queue_entry __wq_entry;                                     \
 276         long __ret = ret;       /* explicit shadow */                           \
 277                                                                                 \
 278         init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0);        \
 279         for (;;) {                                                              \
 280                 long __int = prepare_to_wait_event(&wq_head, &__wq_entry, state);\
 281                                                                                 \
 282                 if (condition)                                                  \
 283                         break;                                                  \
 284                                                                                 \
 285                 if (___wait_is_interruptible(state) && __int) {                 \
 286                         __ret = __int;                                          \
 287                         goto __out;                                             \
 288                 }                                                               \
 289                                                                                 \
 290                 cmd;                                                            \
 291         }                                                                       \
 292         finish_wait(&wq_head, &__wq_entry);                                     \
 293 __out:  __ret;                                                                  \
 294 })
 295
 296 #define __wait_event(wq_head, condition)                                        \
 297         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
 298                             schedule())
 299
 300 /**
 301  * wait_event - sleep until a condition gets true
 302  * @wq_head: the waitqueue to wait on
 303  * @condition: a C expression for the event to wait for
 304  *
 305  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 306  * @condition evaluates to true. The @condition is checked each time
 307  * the waitqueue @wq_head is woken up.
 308  *
 309  * wake_up() has to be called after changing any variable that could
 310  * change the result of the wait condition.
 311  */
 312 #define wait_event(wq_head, condition)                                          \
 313 do {                                                                            \
 314         might_sleep();                                                          \
 315         if (condition)                                                          \
 316                 break;                                                          \
 317         __wait_event(wq_head, condition);                                       \
 318 } while (0)
 319
 320 #define __io_wait_event(wq_head, condition)                                     \
 321         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
 322                             io_schedule())
 323
 324 /*
 325  * io_wait_event() -- like wait_event() but with io_schedule()
 326  */
 327 #define io_wait_event(wq_head, condition)                                       \
 328 do {                                                                            \
 329         might_sleep();                                                          \
 330         if (condition)                                                          \
 331                 break;                                                          \
 332         __io_wait_event(wq_head, condition);                                    \
 333 } while (0)
 334
 335 #define __wait_event_freezable(wq_head, condition)                              \
 336         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
 337                             schedule(); try_to_freeze())
 338
 339 /**
 340  * wait_event_freezable - sleep (or freeze) until a condition gets true
 341  * @wq_head: the waitqueue to wait on
 342  * @condition: a C expression for the event to wait for
 343  *
 344  * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
 345  * to system load) until the @condition evaluates to true. The
 346  * @condition is checked each time the waitqueue @wq_head is woken up.
 347  *
 348  * wake_up() has to be called after changing any variable that could
 349  * change the result of the wait condition.
 350  */
 351 #define wait_event_freezable(wq_head, condition)                                \
 352 ({                                                                              \
 353         int __ret = 0;                                                          \
 354         might_sleep();                                                          \
 355         if (!(condition))                                                       \
 356                 __ret = __wait_event_freezable(wq_head, condition);             \
 357         __ret;                                                                  \
 358 })
 359
 360 #define __wait_event_timeout(wq_head, condition, timeout)                       \
 361         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 362                       TASK_UNINTERRUPTIBLE, 0, timeout,                         \
 363                       __ret = schedule_timeout(__ret))
 364
 365 /**
 366  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 367  * @wq_head: the waitqueue to wait on
 368  * @condition: a C expression for the event to wait for
 369  * @timeout: timeout, in jiffies
 370  *
 371  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 372  * @condition evaluates to true. The @condition is checked each time
 373  * the waitqueue @wq_head is woken up.
 374  *
 375  * wake_up() has to be called after changing any variable that could
 376  * change the result of the wait condition.
 377  *
 378  * Returns:
 379  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 380  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 381  * or the remaining jiffies (at least 1) if the @condition evaluated
 382  * to %true before the @timeout elapsed.
 383  */
 384 #define wait_event_timeout(wq_head, condition, timeout)                         \
 385 ({                                                                              \
 386         long __ret = timeout;                                                   \
 387         might_sleep();                                                          \
 388         if (!___wait_cond_timeout(condition))                                   \
 389                 __ret = __wait_event_timeout(wq_head, condition, timeout);      \
 390         __ret;                                                                  \
 391 })
 392
 393 #define __wait_event_freezable_timeout(wq_head, condition, timeout)             \
 394         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 395                       TASK_INTERRUPTIBLE, 0, timeout,                           \
 396                       __ret = schedule_timeout(__ret); try_to_freeze())
 397
 398 /*
 399  * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
 400  * increasing load and is freezable.
 401  */
 402 #define wait_event_freezable_timeout(wq_head, condition, timeout)               \
 403 ({                                                                              \
 404         long __ret = timeout;                                                   \
 405         might_sleep();                                                          \
 406         if (!___wait_cond_timeout(condition))                                   \
 407                 __ret = __wait_event_freezable_timeout(wq_head, condition, timeout); \
 408         __ret;                                                                  \
 409 })
 410
 411 #define __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2)              \
 412         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 1, 0,     \
 413                             cmd1; schedule(); cmd2)
 414 /*
 415  * Just like wait_event_cmd(), except it sets exclusive flag
 416  */
 417 #define wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2)                \
 418 do {                                                                            \
 419         if (condition)                                                          \
 420                 break;                                                          \
 421         __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2);             \
 422 } while (0)
 423
 424 #define __wait_event_cmd(wq_head, condition, cmd1, cmd2)                        \
 425         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
 426                             cmd1; schedule(); cmd2)
 427
 428 /**
 429  * wait_event_cmd - sleep until a condition gets true
 430  * @wq_head: the waitqueue to wait on
 431  * @condition: a C expression for the event to wait for
 432  * @cmd1: the command will be executed before sleep
 433  * @cmd2: the command will be executed after sleep
 434  *
 435  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 436  * @condition evaluates to true. The @condition is checked each time
 437  * the waitqueue @wq_head is woken up.
 438  *
 439  * wake_up() has to be called after changing any variable that could
 440  * change the result of the wait condition.
 441  */
 442 #define wait_event_cmd(wq_head, condition, cmd1, cmd2)                          \
 443 do {                                                                            \
 444         if (condition)                                                          \
 445                 break;                                                          \
 446         __wait_event_cmd(wq_head, condition, cmd1, cmd2);                       \
 447 } while (0)
 448
 449 #define __wait_event_interruptible(wq_head, condition)                          \
 450         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
 451                       schedule())
 452
 453 /**
 454  * wait_event_interruptible - sleep until a condition gets true
 455  * @wq_head: the waitqueue to wait on
 456  * @condition: a C expression for the event to wait for
 457  *
 458  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 459  * @condition evaluates to true or a signal is received.
 460  * The @condition is checked each time the waitqueue @wq_head is woken up.
 461  *
 462  * wake_up() has to be called after changing any variable that could
 463  * change the result of the wait condition.
 464  *
 465  * The function will return -ERESTARTSYS if it was interrupted by a
 466  * signal and 0 if @condition evaluated to true.
 467  */
 468 #define wait_event_interruptible(wq_head, condition)                            \
 469 ({                                                                              \
 470         int __ret = 0;                                                          \
 471         might_sleep();                                                          \
 472         if (!(condition))                                                       \
 473                 __ret = __wait_event_interruptible(wq_head, condition);         \
 474         __ret;                                                                  \
 475 })
 476
 477 #define __wait_event_interruptible_timeout(wq_head, condition, timeout)         \
 478         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 479                       TASK_INTERRUPTIBLE, 0, timeout,                           \
 480                       __ret = schedule_timeout(__ret))
 481
 482 /**
 483  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 484  * @wq_head: the waitqueue to wait on
 485  * @condition: a C expression for the event to wait for
 486  * @timeout: timeout, in jiffies
 487  *
 488  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 489  * @condition evaluates to true or a signal is received.
 490  * The @condition is checked each time the waitqueue @wq_head is woken up.
 491  *
 492  * wake_up() has to be called after changing any variable that could
 493  * change the result of the wait condition.
 494  *
 495  * Returns:
 496  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 497  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 498  * the remaining jiffies (at least 1) if the @condition evaluated
 499  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
 500  * interrupted by a signal.
 501  */
 502 #define wait_event_interruptible_timeout(wq_head, condition, timeout)           \
 503 ({                                                                              \
 504         long __ret = timeout;                                                   \
 505         might_sleep();                                                          \
 506         if (!___wait_cond_timeout(condition))                                   \
 507                 __ret = __wait_event_interruptible_timeout(wq_head,             \
 508                                                 condition, timeout);            \
 509         __ret;                                                                  \
 510 })
 511
 512 #define __wait_event_hrtimeout(wq_head, condition, timeout, state)              \
 513 ({                                                                              \
 514         int __ret = 0;                                                          \
 515         struct hrtimer_sleeper __t;                                             \
 516                                                                                 \
 517         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);   \
 518         hrtimer_init_sleeper(&__t, current);                                    \
 519         if ((timeout) != KTIME_MAX)                                             \
 520                 hrtimer_start_range_ns(&__t.timer, timeout,                     \
 521                                        current->timer_slack_ns,                 \
 522                                        HRTIMER_MODE_REL);                       \
 523                                                                                 \
 524         __ret = ___wait_event(wq_head, condition, state, 0, 0,                  \
 525                 if (!__t.task) {                                                \
 526                         __ret = -ETIME;                                         \
 527                         break;                                                  \
 528                 }                                                               \
 529                 schedule());                                                    \
 530                                                                                 \
 531         hrtimer_cancel(&__t.timer);                                             \
 532         destroy_hrtimer_on_stack(&__t.timer);                                   \
 533         __ret;                                                                  \
 534 })
 535
 536 /**
 537  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
 538  * @wq_head: 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_UNINTERRUPTIBLE) until the
 543  * @condition evaluates to true or a signal is received.
 544  * The @condition is checked each time the waitqueue @wq_head 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, or -ETIME if the timeout
 550  * elapsed.
 551  */
 552 #define wait_event_hrtimeout(wq_head, condition, timeout)                       \
 553 ({                                                                              \
 554         int __ret = 0;                                                          \
 555         might_sleep();                                                          \
 556         if (!(condition))                                                       \
 557                 __ret = __wait_event_hrtimeout(wq_head, condition, timeout,     \
 558                                                TASK_UNINTERRUPTIBLE);           \
 559         __ret;                                                                  \
 560 })
 561
 562 /**
 563  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
 564  * @wq: the waitqueue to wait on
 565  * @condition: a C expression for the event to wait for
 566  * @timeout: timeout, as a ktime_t
 567  *
 568  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 569  * @condition evaluates to true or a signal is received.
 570  * The @condition is checked each time the waitqueue @wq is woken up.
 571  *
 572  * wake_up() has to be called after changing any variable that could
 573  * change the result of the wait condition.
 574  *
 575  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
 576  * interrupted by a signal, or -ETIME if the timeout elapsed.
 577  */
 578 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)              \
 579 ({                                                                              \
 580         long __ret = 0;                                                         \
 581         might_sleep();                                                          \
 582         if (!(condition))                                                       \
 583                 __ret = __wait_event_hrtimeout(wq, condition, timeout,          \
 584                                                TASK_INTERRUPTIBLE);             \
 585         __ret;                                                                  \
 586 })
 587
 588 #define __wait_event_interruptible_exclusive(wq, condition)                     \
 589         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,                  \
 590                       schedule())
 591
 592 #define wait_event_interruptible_exclusive(wq, condition)                       \
 593 ({                                                                              \
 594         int __ret = 0;                                                          \
 595         might_sleep();                                                          \
 596         if (!(condition))                                                       \
 597                 __ret = __wait_event_interruptible_exclusive(wq, condition);    \
 598         __ret;                                                                  \
 599 })
 600
 601 #define __wait_event_killable_exclusive(wq, condition)                          \
 602         ___wait_event(wq, condition, TASK_KILLABLE, 1, 0,                       \
 603                       schedule())
 604
 605 #define wait_event_killable_exclusive(wq, condition)                            \
 606 ({                                                                              \
 607         int __ret = 0;                                                          \
 608         might_sleep();                                                          \
 609         if (!(condition))                                                       \
 610                 __ret = __wait_event_killable_exclusive(wq, condition);         \
 611         __ret;                                                                  \
 612 })
 613
 614
 615 #define __wait_event_freezable_exclusive(wq, condition)                         \
 616         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,                  \
 617                         schedule(); try_to_freeze())
 618
 619 #define wait_event_freezable_exclusive(wq, condition)                           \
 620 ({                                                                              \
 621         int __ret = 0;                                                          \
 622         might_sleep();                                                          \
 623         if (!(condition))                                                       \
 624                 __ret = __wait_event_freezable_exclusive(wq, condition);        \
 625         __ret;                                                                  \
 626 })
 627
 628 /**
 629  * wait_event_idle - wait for a condition without contributing to system load
 630  * @wq_head: the waitqueue to wait on
 631  * @condition: a C expression for the event to wait for
 632  *
 633  * The process is put to sleep (TASK_IDLE) until the
 634  * @condition evaluates to true.
 635  * The @condition is checked each time the waitqueue @wq_head is woken up.
 636  *
 637  * wake_up() has to be called after changing any variable that could
 638  * change the result of the wait condition.
 639  *
 640  */
 641 #define wait_event_idle(wq_head, condition)                                     \
 642 do {                                                                            \
 643         might_sleep();                                                          \
 644         if (!(condition))                                                       \
 645                 ___wait_event(wq_head, condition, TASK_IDLE, 0, 0, schedule()); \
 646 } while (0)
 647
 648 /**
 649  * wait_event_idle_exclusive - wait for a condition with contributing to system load
 650  * @wq_head: the waitqueue to wait on
 651  * @condition: a C expression for the event to wait for
 652  *
 653  * The process is put to sleep (TASK_IDLE) until the
 654  * @condition evaluates to true.
 655  * The @condition is checked each time the waitqueue @wq_head is woken up.
 656  *
 657  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 658  * set thus if other processes wait on the same list, when this
 659  * process is woken further processes are not considered.
 660  *
 661  * wake_up() has to be called after changing any variable that could
 662  * change the result of the wait condition.
 663  *
 664  */
 665 #define wait_event_idle_exclusive(wq_head, condition)                           \
 666 do {                                                                            \
 667         might_sleep();                                                          \
 668         if (!(condition))                                                       \
 669                 ___wait_event(wq_head, condition, TASK_IDLE, 1, 0, schedule()); \
 670 } while (0)
 671
 672 #define __wait_event_idle_timeout(wq_head, condition, timeout)                  \
 673         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 674                       TASK_IDLE, 0, timeout,                                    \
 675                       __ret = schedule_timeout(__ret))
 676
 677 /**
 678  * wait_event_idle_timeout - sleep without load until a condition becomes true or a timeout elapses
 679  * @wq_head: the waitqueue to wait on
 680  * @condition: a C expression for the event to wait for
 681  * @timeout: timeout, in jiffies
 682  *
 683  * The process is put to sleep (TASK_IDLE) until the
 684  * @condition evaluates to true. The @condition is checked each time
 685  * the waitqueue @wq_head is woken up.
 686  *
 687  * wake_up() has to be called after changing any variable that could
 688  * change the result of the wait condition.
 689  *
 690  * Returns:
 691  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 692  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 693  * or the remaining jiffies (at least 1) if the @condition evaluated
 694  * to %true before the @timeout elapsed.
 695  */
 696 #define wait_event_idle_timeout(wq_head, condition, timeout)                    \
 697 ({                                                                              \
 698         long __ret = timeout;                                                   \
 699         might_sleep();                                                          \
 700         if (!___wait_cond_timeout(condition))                                   \
 701                 __ret = __wait_event_idle_timeout(wq_head, condition, timeout); \
 702         __ret;                                                                  \
 703 })
 704
 705 #define __wait_event_idle_exclusive_timeout(wq_head, condition, timeout)        \
 706         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 707                       TASK_IDLE, 1, timeout,                                    \
 708                       __ret = schedule_timeout(__ret))
 709
 710 /**
 711  * wait_event_idle_exclusive_timeout - sleep without load until a condition becomes true or a timeout elapses
 712  * @wq_head: the waitqueue to wait on
 713  * @condition: a C expression for the event to wait for
 714  * @timeout: timeout, in jiffies
 715  *
 716  * The process is put to sleep (TASK_IDLE) until the
 717  * @condition evaluates to true. The @condition is checked each time
 718  * the waitqueue @wq_head is woken up.
 719  *
 720  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 721  * set thus if other processes wait on the same list, when this
 722  * process is woken further processes are not considered.
 723  *
 724  * wake_up() has to be called after changing any variable that could
 725  * change the result of the wait condition.
 726  *
 727  * Returns:
 728  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 729  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 730  * or the remaining jiffies (at least 1) if the @condition evaluated
 731  * to %true before the @timeout elapsed.
 732  */
 733 #define wait_event_idle_exclusive_timeout(wq_head, condition, timeout)          \
 734 ({                                                                              \
 735         long __ret = timeout;                                                   \
 736         might_sleep();                                                          \
 737         if (!___wait_cond_timeout(condition))                                   \
 738                 __ret = __wait_event_idle_exclusive_timeout(wq_head, condition, timeout);\
 739         __ret;                                                                  \
 740 })
 741
 742 extern int do_wait_intr(wait_queue_head_t *, wait_queue_entry_t *);
 743 extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *);
 744
 745 #define __wait_event_interruptible_locked(wq, condition, exclusive, fn)         \
 746 ({                                                                              \
 747         int __ret;                                                              \
 748         DEFINE_WAIT(__wait);                                                    \
 749         if (exclusive)                                                          \
 750                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                              \
 751         do {                                                                    \
 752                 __ret = fn(&(wq), &__wait);                                     \
 753                 if (__ret)                                                      \
 754                         break;                                                  \
 755         } while (!(condition));                                                 \
 756         __remove_wait_queue(&(wq), &__wait);                                    \
 757         __set_current_state(TASK_RUNNING);                                      \
 758         __ret;                                                                  \
 759 })
 760
 761
 762 /**
 763  * wait_event_interruptible_locked - sleep until a condition gets true
 764  * @wq: the waitqueue to wait on
 765  * @condition: a C expression for the event to wait for
 766  *
 767  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 768  * @condition evaluates to true or a signal is received.
 769  * The @condition is checked each time the waitqueue @wq is woken up.
 770  *
 771  * It must be called with wq.lock being held.  This spinlock is
 772  * unlocked while sleeping but @condition testing is done while lock
 773  * is held and when this macro exits the lock is held.
 774  *
 775  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 776  * functions which must match the way they are locked/unlocked outside
 777  * of this macro.
 778  *
 779  * wake_up_locked() has to be called after changing any variable that could
 780  * change the result of the wait condition.
 781  *
 782  * The function will return -ERESTARTSYS if it was interrupted by a
 783  * signal and 0 if @condition evaluated to true.
 784  */
 785 #define wait_event_interruptible_locked(wq, condition)                          \
 786         ((condition)                                                            \
 787          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr))
 788
 789 /**
 790  * wait_event_interruptible_locked_irq - sleep until a condition gets true
 791  * @wq: the waitqueue to wait on
 792  * @condition: a C expression for the event to wait for
 793  *
 794  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 795  * @condition evaluates to true or a signal is received.
 796  * The @condition is checked each time the waitqueue @wq is woken up.
 797  *
 798  * It must be called with wq.lock being held.  This spinlock is
 799  * unlocked while sleeping but @condition testing is done while lock
 800  * is held and when this macro exits the lock is held.
 801  *
 802  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 803  * functions which must match the way they are locked/unlocked outside
 804  * of this macro.
 805  *
 806  * wake_up_locked() has to be called after changing any variable that could
 807  * change the result of the wait condition.
 808  *
 809  * The function will return -ERESTARTSYS if it was interrupted by a
 810  * signal and 0 if @condition evaluated to true.
 811  */
 812 #define wait_event_interruptible_locked_irq(wq, condition)                      \
 813         ((condition)                                                            \
 814          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr_irq))
 815
 816 /**
 817  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
 818  * @wq: the waitqueue to wait on
 819  * @condition: a C expression for the event to wait for
 820  *
 821  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 822  * @condition evaluates to true or a signal is received.
 823  * The @condition is checked each time the waitqueue @wq is woken up.
 824  *
 825  * It must be called with wq.lock being held.  This spinlock is
 826  * unlocked while sleeping but @condition testing is done while lock
 827  * is held and when this macro exits the lock is held.
 828  *
 829  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 830  * functions which must match the way they are locked/unlocked outside
 831  * of this macro.
 832  *
 833  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 834  * set thus when other process waits process on the list if this
 835  * process is awaken further processes are not considered.
 836  *
 837  * wake_up_locked() has to be called after changing any variable that could
 838  * change the result of the wait condition.
 839  *
 840  * The function will return -ERESTARTSYS if it was interrupted by a
 841  * signal and 0 if @condition evaluated to true.
 842  */
 843 #define wait_event_interruptible_exclusive_locked(wq, condition)                \
 844         ((condition)                                                            \
 845          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr))
 846
 847 /**
 848  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
 849  * @wq: the waitqueue to wait on
 850  * @condition: a C expression for the event to wait for
 851  *
 852  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 853  * @condition evaluates to true or a signal is received.
 854  * The @condition is checked each time the waitqueue @wq is woken up.
 855  *
 856  * It must be called with wq.lock being held.  This spinlock is
 857  * unlocked while sleeping but @condition testing is done while lock
 858  * is held and when this macro exits the lock is held.
 859  *
 860  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 861  * functions which must match the way they are locked/unlocked outside
 862  * of this macro.
 863  *
 864  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 865  * set thus when other process waits process on the list if this
 866  * process is awaken further processes are not considered.
 867  *
 868  * wake_up_locked() has to be called after changing any variable that could
 869  * change the result of the wait condition.
 870  *
 871  * The function will return -ERESTARTSYS if it was interrupted by a
 872  * signal and 0 if @condition evaluated to true.
 873  */
 874 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)            \
 875         ((condition)                                                            \
 876          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr_irq))
 877
 878
 879 #define __wait_event_killable(wq, condition)                                    \
 880         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
 881
 882 /**
 883  * wait_event_killable - sleep until a condition gets true
 884  * @wq_head: the waitqueue to wait on
 885  * @condition: a C expression for the event to wait for
 886  *
 887  * The process is put to sleep (TASK_KILLABLE) until the
 888  * @condition evaluates to true or a signal is received.
 889  * The @condition is checked each time the waitqueue @wq_head is woken up.
 890  *
 891  * wake_up() has to be called after changing any variable that could
 892  * change the result of the wait condition.
 893  *
 894  * The function will return -ERESTARTSYS if it was interrupted by a
 895  * signal and 0 if @condition evaluated to true.
 896  */
 897 #define wait_event_killable(wq_head, condition)                                 \
 898 ({                                                                              \
 899         int __ret = 0;                                                          \
 900         might_sleep();                                                          \
 901         if (!(condition))                                                       \
 902                 __ret = __wait_event_killable(wq_head, condition);              \
 903         __ret;                                                                  \
 904 })
 905
 906 #define __wait_event_killable_timeout(wq_head, condition, timeout)              \
 907         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 908                       TASK_KILLABLE, 0, timeout,                                \
 909                       __ret = schedule_timeout(__ret))
 910
 911 /**
 912  * wait_event_killable_timeout - sleep until a condition gets true or a timeout elapses
 913  * @wq_head: the waitqueue to wait on
 914  * @condition: a C expression for the event to wait for
 915  * @timeout: timeout, in jiffies
 916  *
 917  * The process is put to sleep (TASK_KILLABLE) until the
 918  * @condition evaluates to true or a kill signal is received.
 919  * The @condition is checked each time the waitqueue @wq_head is woken up.
 920  *
 921  * wake_up() has to be called after changing any variable that could
 922  * change the result of the wait condition.
 923  *
 924  * Returns:
 925  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 926  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 927  * the remaining jiffies (at least 1) if the @condition evaluated
 928  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
 929  * interrupted by a kill signal.
 930  *
 931  * Only kill signals interrupt this process.
 932  */
 933 #define wait_event_killable_timeout(wq_head, condition, timeout)                \
 934 ({                                                                              \
 935         long __ret = timeout;                                                   \
 936         might_sleep();                                                          \
 937         if (!___wait_cond_timeout(condition))                                   \
 938                 __ret = __wait_event_killable_timeout(wq_head,                  \
 939                                                 condition, timeout);            \
 940         __ret;                                                                  \
 941 })
 942
 943
 944 #define __wait_event_lock_irq(wq_head, condition, lock, cmd)                    \
 945         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
 946                             spin_unlock_irq(&lock);                             \
 947                             cmd;                                                \
 948                             schedule();                                         \
 949                             spin_lock_irq(&lock))
 950
 951 /**
 952  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
 953  *                           condition is checked under the lock. This
 954  *                           is expected to be called with the lock
 955  *                           taken.
 956  * @wq_head: the waitqueue to wait on
 957  * @condition: a C expression for the event to wait for
 958  * @lock: a locked spinlock_t, which will be released before cmd
 959  *        and schedule() and reacquired afterwards.
 960  * @cmd: a command which is invoked outside the critical section before
 961  *       sleep
 962  *
 963  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 964  * @condition evaluates to true. The @condition is checked each time
 965  * the waitqueue @wq_head is woken up.
 966  *
 967  * wake_up() has to be called after changing any variable that could
 968  * change the result of the wait condition.
 969  *
 970  * This is supposed to be called while holding the lock. The lock is
 971  * dropped before invoking the cmd and going to sleep and is reacquired
 972  * afterwards.
 973  */
 974 #define wait_event_lock_irq_cmd(wq_head, condition, lock, cmd)                  \
 975 do {                                                                            \
 976         if (condition)                                                          \
 977                 break;                                                          \
 978         __wait_event_lock_irq(wq_head, condition, lock, cmd);                   \
 979 } while (0)
 980
 981 /**
 982  * wait_event_lock_irq - sleep until a condition gets true. The
 983  *                       condition is checked under the lock. This
 984  *                       is expected to be called with the lock
 985  *                       taken.
 986  * @wq_head: the waitqueue to wait on
 987  * @condition: a C expression for the event to wait for
 988  * @lock: a locked spinlock_t, which will be released before schedule()
 989  *        and reacquired afterwards.
 990  *
 991  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 992  * @condition evaluates to true. The @condition is checked each time
 993  * the waitqueue @wq_head is woken up.
 994  *
 995  * wake_up() has to be called after changing any variable that could
 996  * change the result of the wait condition.
 997  *
 998  * This is supposed to be called while holding the lock. The lock is
 999  * dropped before going to sleep and is reacquired afterwards.
1000  */
1001 #define wait_event_lock_irq(wq_head, condition, lock)                           \
1002 do {                                                                            \
1003         if (condition)                                                          \
1004                 break;                                                          \
1005         __wait_event_lock_irq(wq_head, condition, lock, );                      \
1006 } while (0)
1007
1008
1009 #define __wait_event_interruptible_lock_irq(wq_head, condition, lock, cmd)      \
1010         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
1011                       spin_unlock_irq(&lock);                                   \
1012                       cmd;                                                      \
1013                       schedule();                                               \
1014                       spin_lock_irq(&lock))
1015
1016 /**
1017  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
1018  *              The condition is checked under the lock. This is expected to
1019  *              be called with the lock taken.
1020  * @wq_head: the waitqueue to wait on
1021  * @condition: a C expression for the event to wait for
1022  * @lock: a locked spinlock_t, which will be released before cmd and
1023  *        schedule() and reacquired afterwards.
1024  * @cmd: a command which is invoked outside the critical section before
1025  *       sleep
1026  *
1027  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1028  * @condition evaluates to true or a signal is received. The @condition is
1029  * checked each time the waitqueue @wq_head is woken up.
1030  *
1031  * wake_up() has to be called after changing any variable that could
1032  * change the result of the wait condition.
1033  *
1034  * This is supposed to be called while holding the lock. The lock is
1035  * dropped before invoking the cmd and going to sleep and is reacquired
1036  * afterwards.
1037  *
1038  * The macro will return -ERESTARTSYS if it was interrupted by a signal
1039  * and 0 if @condition evaluated to true.
1040  */
1041 #define wait_event_interruptible_lock_irq_cmd(wq_head, condition, lock, cmd)    \
1042 ({                                                                              \
1043         int __ret = 0;                                                          \
1044         if (!(condition))                                                       \
1045                 __ret = __wait_event_interruptible_lock_irq(wq_head,            \
1046                                                 condition, lock, cmd);          \
1047         __ret;                                                                  \
1048 })
1049
1050 /**
1051  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
1052  *              The condition is checked under the lock. This is expected
1053  *              to be called with the lock taken.
1054  * @wq_head: the waitqueue to wait on
1055  * @condition: a C expression for the event to wait for
1056  * @lock: a locked spinlock_t, which will be released before schedule()
1057  *        and reacquired afterwards.
1058  *
1059  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1060  * @condition evaluates to true or signal is received. The @condition is
1061  * checked each time the waitqueue @wq_head is woken up.
1062  *
1063  * wake_up() has to be called after changing any variable that could
1064  * change the result of the wait condition.
1065  *
1066  * This is supposed to be called while holding the lock. The lock is
1067  * dropped before going to sleep and is reacquired afterwards.
1068  *
1069  * The macro will return -ERESTARTSYS if it was interrupted by a signal
1070  * and 0 if @condition evaluated to true.
1071  */
1072 #define wait_event_interruptible_lock_irq(wq_head, condition, lock)             \
1073 ({                                                                              \
1074         int __ret = 0;                                                          \
1075         if (!(condition))                                                       \
1076                 __ret = __wait_event_interruptible_lock_irq(wq_head,            \
1077                                                 condition, lock,);              \
1078         __ret;                                                                  \
1079 })
1080
1081 #define __wait_event_lock_irq_timeout(wq_head, condition, lock, timeout, state) \
1082         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
1083                       state, 0, timeout,                                        \
1084                       spin_unlock_irq(&lock);                                   \
1085                       __ret = schedule_timeout(__ret);                          \
1086                       spin_lock_irq(&lock));
1087
1088 /**
1089  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
1090  *              true or a timeout elapses. The condition is checked under
1091  *              the lock. This is expected to be called with the lock taken.
1092  * @wq_head: the waitqueue to wait on
1093  * @condition: a C expression for the event to wait for
1094  * @lock: a locked spinlock_t, which will be released before schedule()
1095  *        and reacquired afterwards.
1096  * @timeout: timeout, in jiffies
1097  *
1098  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1099  * @condition evaluates to true or signal is received. The @condition is
1100  * checked each time the waitqueue @wq_head is woken up.
1101  *
1102  * wake_up() has to be called after changing any variable that could
1103  * change the result of the wait condition.
1104  *
1105  * This is supposed to be called while holding the lock. The lock is
1106  * dropped before going to sleep and is reacquired afterwards.
1107  *
1108  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
1109  * was interrupted by a signal, and the remaining jiffies otherwise
1110  * if the condition evaluated to true before the timeout elapsed.
1111  */
1112 #define wait_event_interruptible_lock_irq_timeout(wq_head, condition, lock,     \
1113                                                   timeout)                      \
1114 ({                                                                              \
1115         long __ret = timeout;                                                   \
1116         if (!___wait_cond_timeout(condition))                                   \
1117                 __ret = __wait_event_lock_irq_timeout(                          \
1118                                         wq_head, condition, lock, timeout,      \
1119                                         TASK_INTERRUPTIBLE);                    \
1120         __ret;                                                                  \
1121 })
1122
1123 #define wait_event_lock_irq_timeout(wq_head, condition, lock, timeout)          \
1124 ({                                                                              \
1125         long __ret = timeout;                                                   \
1126         if (!___wait_cond_timeout(condition))                                   \
1127                 __ret = __wait_event_lock_irq_timeout(                          \
1128                                         wq_head, condition, lock, timeout,      \
1129                                         TASK_UNINTERRUPTIBLE);                  \
1130         __ret;                                                                  \
1131 })
1132
1133 /*
1134  * Waitqueues which are removed from the waitqueue_head at wakeup time
1135  */
1136 void prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1137 void prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1138 long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1139 void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
1140 long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout);
1141 int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
1142 int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
1143
1144 #define DEFINE_WAIT_FUNC(name, function)                                        \
1145         struct wait_queue_entry name = {                                        \
1146                 .private        = current,                                      \
1147                 .func           = function,                                     \
1148                 .entry          = LIST_HEAD_INIT((name).entry),                 \
1149         }
1150
1151 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
1152
1153 #define init_wait(wait)                                                         \
1154         do {                                                                    \
1155                 (wait)->private = current;                                      \
1156                 (wait)->func = autoremove_wake_function;                        \
1157                 INIT_LIST_HEAD(&(wait)->entry);                                 \
1158                 (wait)->flags = 0;                                              \
1159         } while (0)
1160
1161 #endif /* _LINUX_WAIT_H */