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 #define WQ_FLAG_CUSTOM          0x08
  24 #define WQ_FLAG_DONE            0x10
  25 #define WQ_FLAG_PRIORITY        0x20
  26
  27 /*
  28  * A single wait-queue entry structure:
  29  */
  30 struct wait_queue_entry {
  31         unsigned int            flags;
  32         void                    *private;
  33         wait_queue_func_t       func;
  34         struct list_head        entry;
  35 };
  36
  37 struct wait_queue_head {
  38         spinlock_t              lock;
  39         struct list_head        head;
  40 };
  41 typedef struct wait_queue_head wait_queue_head_t;
  42
  43 struct task_struct;
  44
  45 /*
  46  * Macros for declaration and initialisaton of the datatypes
  47  */
  48
  49 #define __WAITQUEUE_INITIALIZER(name, tsk) {                                    \
  50         .private        = tsk,                                                  \
  51         .func           = default_wake_function,                                \
  52         .entry          = { NULL, NULL } }
  53
  54 #define DECLARE_WAITQUEUE(name, tsk)                                            \
  55         struct wait_queue_entry name = __WAITQUEUE_INITIALIZER(name, tsk)
  56
  57 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                                   \
  58         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),                      \
  59         .head           = { &(name).head, &(name).head } }
  60
  61 #define DECLARE_WAIT_QUEUE_HEAD(name) \
  62         struct wait_queue_head name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
  63
  64 extern void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *);
  65
  66 #define init_waitqueue_head(wq_head)                                            \
  67         do {                                                                    \
  68                 static struct lock_class_key __key;                             \
  69                                                                                 \
  70                 __init_waitqueue_head((wq_head), #wq_head, &__key);             \
  71         } while (0)
  72
  73 #ifdef CONFIG_LOCKDEP
  74 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
  75         ({ init_waitqueue_head(&name); name; })
  76 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
  77         struct wait_queue_head name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
  78 #else
  79 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
  80 #endif
  81
  82 static inline void init_waitqueue_entry(struct wait_queue_entry *wq_entry, struct task_struct *p)
  83 {
  84         wq_entry->flags         = 0;
  85         wq_entry->private       = p;
  86         wq_entry->func          = default_wake_function;
  87 }
  88
  89 static inline void
  90 init_waitqueue_func_entry(struct wait_queue_entry *wq_entry, wait_queue_func_t func)
  91 {
  92         wq_entry->flags         = 0;
  93         wq_entry->private       = NULL;
  94         wq_entry->func          = func;
  95 }
  96
  97 /**
  98  * waitqueue_active -- locklessly test for waiters on the queue
  99  * @wq_head: the waitqueue to test for waiters
 100  *
 101  * returns true if the wait list is not empty
 102  *
 103  * NOTE: this function is lockless and requires care, incorrect usage _will_
 104  * lead to sporadic and non-obvious failure.
 105  *
 106  * Use either while holding wait_queue_head::lock or when used for wakeups
 107  * with an extra smp_mb() like::
 108  *
 109  *      CPU0 - waker                    CPU1 - waiter
 110  *
 111  *                                      for (;;) {
 112  *      @cond = true;                     prepare_to_wait(&wq_head, &wait, state);
 113  *      smp_mb();                         // smp_mb() from set_current_state()
 114  *      if (waitqueue_active(wq_head))         if (@cond)
 115  *        wake_up(wq_head);                      break;
 116  *                                        schedule();
 117  *                                      }
 118  *                                      finish_wait(&wq_head, &wait);
 119  *
 120  * Because without the explicit smp_mb() it's possible for the
 121  * waitqueue_active() load to get hoisted over the @cond store such that we'll
 122  * observe an empty wait list while the waiter might not observe @cond.
 123  *
 124  * Also note that this 'optimization' trades a spin_lock() for an smp_mb(),
 125  * which (when the lock is uncontended) are of roughly equal cost.
 126  */
 127 static inline int waitqueue_active(struct wait_queue_head *wq_head)
 128 {
 129         return !list_empty(&wq_head->head);
 130 }
 131
 132 /**
 133  * wq_has_single_sleeper - check if there is only one sleeper
 134  * @wq_head: wait queue head
 135  *
 136  * Returns true of wq_head has only one sleeper on the list.
 137  *
 138  * Please refer to the comment for waitqueue_active.
 139  */
 140 static inline bool wq_has_single_sleeper(struct wait_queue_head *wq_head)
 141 {
 142         return list_is_singular(&wq_head->head);
 143 }
 144
 145 /**
 146  * wq_has_sleeper - check if there are any waiting processes
 147  * @wq_head: wait queue head
 148  *
 149  * Returns true if wq_head has waiting processes
 150  *
 151  * Please refer to the comment for waitqueue_active.
 152  */
 153 static inline bool wq_has_sleeper(struct wait_queue_head *wq_head)
 154 {
 155         /*
 156          * We need to be sure we are in sync with the
 157          * add_wait_queue modifications to the wait queue.
 158          *
 159          * This memory barrier should be paired with one on the
 160          * waiting side.
 161          */
 162         smp_mb();
 163         return waitqueue_active(wq_head);
 164 }
 165
 166 extern void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
 167 extern void add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
 168 extern void add_wait_queue_priority(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
 169 extern void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
 170
 171 static inline void __add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
 172 {
 173         struct list_head *head = &wq_head->head;
 174         struct wait_queue_entry *wq;
 175
 176         list_for_each_entry(wq, &wq_head->head, entry) {
 177                 if (!(wq->flags & WQ_FLAG_PRIORITY))
 178                         break;
 179                 head = &wq->entry;
 180         }
 181         list_add(&wq_entry->entry, head);
 182 }
 183
 184 /*
 185  * Used for wake-one threads:
 186  */
 187 static inline void
 188 __add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
 189 {
 190         wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
 191         __add_wait_queue(wq_head, wq_entry);
 192 }
 193
 194 static inline void __add_wait_queue_entry_tail(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
 195 {
 196         list_add_tail(&wq_entry->entry, &wq_head->head);
 197 }
 198
 199 static inline void
 200 __add_wait_queue_entry_tail_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
 201 {
 202         wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
 203         __add_wait_queue_entry_tail(wq_head, wq_entry);
 204 }
 205
 206 static inline void
 207 __remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
 208 {
 209         list_del(&wq_entry->entry);
 210 }
 211
 212 void __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
 213 void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
 214 void __wake_up_locked_key_bookmark(struct wait_queue_head *wq_head,
 215                 unsigned int mode, void *key, wait_queue_entry_t *bookmark);
 216 void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
 217 void __wake_up_locked_sync_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
 218 void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr);
 219 void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode);
 220
 221 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
 222 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
 223 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
 224 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL, 1)
 225 #define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)
 226
 227 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 228 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
 229 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
 230 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE)
 231
 232 /*
 233  * Wakeup macros to be used to report events to the targets.
 234  */
 235 #define poll_to_key(m) ((void *)(__force uintptr_t)(__poll_t)(m))
 236 #define key_to_poll(m) ((__force __poll_t)(uintptr_t)(void *)(m))
 237 #define wake_up_poll(x, m)                                                      \
 238         __wake_up(x, TASK_NORMAL, 1, poll_to_key(m))
 239 #define wake_up_locked_poll(x, m)                                               \
 240         __wake_up_locked_key((x), TASK_NORMAL, poll_to_key(m))
 241 #define wake_up_interruptible_poll(x, m)                                        \
 242         __wake_up(x, TASK_INTERRUPTIBLE, 1, poll_to_key(m))
 243 #define wake_up_interruptible_sync_poll(x, m)                                   \
 244         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, poll_to_key(m))
 245 #define wake_up_interruptible_sync_poll_locked(x, m)                            \
 246         __wake_up_locked_sync_key((x), TASK_INTERRUPTIBLE, poll_to_key(m))
 247
 248 #define ___wait_cond_timeout(condition)                                         \
 249 ({                                                                              \
 250         bool __cond = (condition);                                              \
 251         if (__cond && !__ret)                                                   \
 252                 __ret = 1;                                                      \
 253         __cond || !__ret;                                                       \
 254 })
 255
 256 #define ___wait_is_interruptible(state)                                         \
 257         (!__builtin_constant_p(state) ||                                        \
 258                 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE)          \
 259
 260 extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags);
 261
 262 /*
 263  * The below macro ___wait_event() has an explicit shadow of the __ret
 264  * variable when used from the wait_event_*() macros.
 265  *
 266  * This is so that both can use the ___wait_cond_timeout() construct
 267  * to wrap the condition.
 268  *
 269  * The type inconsistency of the wait_event_*() __ret variable is also
 270  * on purpose; we use long where we can return timeout values and int
 271  * otherwise.
 272  */
 273
 274 #define ___wait_event(wq_head, condition, state, exclusive, ret, cmd)           \
 275 ({                                                                              \
 276         __label__ __out;                                                        \
 277         struct wait_queue_entry __wq_entry;                                     \
 278         long __ret = ret;       /* explicit shadow */                           \
 279                                                                                 \
 280         init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0);        \
 281         for (;;) {                                                              \
 282                 long __int = prepare_to_wait_event(&wq_head, &__wq_entry, state);\
 283                                                                                 \
 284                 if (condition)                                                  \
 285                         break;                                                  \
 286                                                                                 \
 287                 if (___wait_is_interruptible(state) && __int) {                 \
 288                         __ret = __int;                                          \
 289                         goto __out;                                             \
 290                 }                                                               \
 291                                                                                 \
 292                 cmd;                                                            \
 293         }                                                                       \
 294         finish_wait(&wq_head, &__wq_entry);                                     \
 295 __out:  __ret;                                                                  \
 296 })
 297
 298 #define __wait_event(wq_head, condition)                                        \
 299         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
 300                             schedule())
 301
 302 /**
 303  * wait_event - sleep until a condition gets true
 304  * @wq_head: the waitqueue to wait on
 305  * @condition: a C expression for the event to wait for
 306  *
 307  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 308  * @condition evaluates to true. The @condition is checked each time
 309  * the waitqueue @wq_head is woken up.
 310  *
 311  * wake_up() has to be called after changing any variable that could
 312  * change the result of the wait condition.
 313  */
 314 #define wait_event(wq_head, condition)                                          \
 315 do {                                                                            \
 316         might_sleep();                                                          \
 317         if (condition)                                                          \
 318                 break;                                                          \
 319         __wait_event(wq_head, condition);                                       \
 320 } while (0)
 321
 322 #define __io_wait_event(wq_head, condition)                                     \
 323         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
 324                             io_schedule())
 325
 326 /*
 327  * io_wait_event() -- like wait_event() but with io_schedule()
 328  */
 329 #define io_wait_event(wq_head, condition)                                       \
 330 do {                                                                            \
 331         might_sleep();                                                          \
 332         if (condition)                                                          \
 333                 break;                                                          \
 334         __io_wait_event(wq_head, condition);                                    \
 335 } while (0)
 336
 337 #define __wait_event_freezable(wq_head, condition)                              \
 338         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
 339                             freezable_schedule())
 340
 341 /**
 342  * wait_event_freezable - sleep (or freeze) until a condition gets true
 343  * @wq_head: the waitqueue to wait on
 344  * @condition: a C expression for the event to wait for
 345  *
 346  * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
 347  * to system load) until the @condition evaluates to true. The
 348  * @condition is checked each time the waitqueue @wq_head is woken up.
 349  *
 350  * wake_up() has to be called after changing any variable that could
 351  * change the result of the wait condition.
 352  */
 353 #define wait_event_freezable(wq_head, condition)                                \
 354 ({                                                                              \
 355         int __ret = 0;                                                          \
 356         might_sleep();                                                          \
 357         if (!(condition))                                                       \
 358                 __ret = __wait_event_freezable(wq_head, condition);             \
 359         __ret;                                                                  \
 360 })
 361
 362 #define __wait_event_timeout(wq_head, condition, timeout)                       \
 363         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 364                       TASK_UNINTERRUPTIBLE, 0, timeout,                         \
 365                       __ret = schedule_timeout(__ret))
 366
 367 /**
 368  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 369  * @wq_head: the waitqueue to wait on
 370  * @condition: a C expression for the event to wait for
 371  * @timeout: timeout, in jiffies
 372  *
 373  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 374  * @condition evaluates to true. The @condition is checked each time
 375  * the waitqueue @wq_head is woken up.
 376  *
 377  * wake_up() has to be called after changing any variable that could
 378  * change the result of the wait condition.
 379  *
 380  * Returns:
 381  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 382  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 383  * or the remaining jiffies (at least 1) if the @condition evaluated
 384  * to %true before the @timeout elapsed.
 385  */
 386 #define wait_event_timeout(wq_head, condition, timeout)                         \
 387 ({                                                                              \
 388         long __ret = timeout;                                                   \
 389         might_sleep();                                                          \
 390         if (!___wait_cond_timeout(condition))                                   \
 391                 __ret = __wait_event_timeout(wq_head, condition, timeout);      \
 392         __ret;                                                                  \
 393 })
 394
 395 #define __wait_event_freezable_timeout(wq_head, condition, timeout)             \
 396         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 397                       TASK_INTERRUPTIBLE, 0, timeout,                           \
 398                       __ret = freezable_schedule_timeout(__ret))
 399
 400 /*
 401  * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
 402  * increasing load and is freezable.
 403  */
 404 #define wait_event_freezable_timeout(wq_head, condition, timeout)               \
 405 ({                                                                              \
 406         long __ret = timeout;                                                   \
 407         might_sleep();                                                          \
 408         if (!___wait_cond_timeout(condition))                                   \
 409                 __ret = __wait_event_freezable_timeout(wq_head, condition, timeout); \
 410         __ret;                                                                  \
 411 })
 412
 413 #define __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2)              \
 414         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 1, 0,     \
 415                             cmd1; schedule(); cmd2)
 416 /*
 417  * Just like wait_event_cmd(), except it sets exclusive flag
 418  */
 419 #define wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2)                \
 420 do {                                                                            \
 421         if (condition)                                                          \
 422                 break;                                                          \
 423         __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2);             \
 424 } while (0)
 425
 426 #define __wait_event_cmd(wq_head, condition, cmd1, cmd2)                        \
 427         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
 428                             cmd1; schedule(); cmd2)
 429
 430 /**
 431  * wait_event_cmd - sleep until a condition gets true
 432  * @wq_head: the waitqueue to wait on
 433  * @condition: a C expression for the event to wait for
 434  * @cmd1: the command will be executed before sleep
 435  * @cmd2: the command will be executed after sleep
 436  *
 437  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 438  * @condition evaluates to true. The @condition is checked each time
 439  * the waitqueue @wq_head is woken up.
 440  *
 441  * wake_up() has to be called after changing any variable that could
 442  * change the result of the wait condition.
 443  */
 444 #define wait_event_cmd(wq_head, condition, cmd1, cmd2)                          \
 445 do {                                                                            \
 446         if (condition)                                                          \
 447                 break;                                                          \
 448         __wait_event_cmd(wq_head, condition, cmd1, cmd2);                       \
 449 } while (0)
 450
 451 #define __wait_event_interruptible(wq_head, condition)                          \
 452         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
 453                       schedule())
 454
 455 /**
 456  * wait_event_interruptible - sleep until a condition gets true
 457  * @wq_head: the waitqueue to wait on
 458  * @condition: a C expression for the event to wait for
 459  *
 460  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 461  * @condition evaluates to true or a signal is received.
 462  * The @condition is checked each time the waitqueue @wq_head is woken up.
 463  *
 464  * wake_up() has to be called after changing any variable that could
 465  * change the result of the wait condition.
 466  *
 467  * The function will return -ERESTARTSYS if it was interrupted by a
 468  * signal and 0 if @condition evaluated to true.
 469  */
 470 #define wait_event_interruptible(wq_head, condition)                            \
 471 ({                                                                              \
 472         int __ret = 0;                                                          \
 473         might_sleep();                                                          \
 474         if (!(condition))                                                       \
 475                 __ret = __wait_event_interruptible(wq_head, condition);         \
 476         __ret;                                                                  \
 477 })
 478
 479 #define __wait_event_interruptible_timeout(wq_head, condition, timeout)         \
 480         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 481                       TASK_INTERRUPTIBLE, 0, timeout,                           \
 482                       __ret = schedule_timeout(__ret))
 483
 484 /**
 485  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 486  * @wq_head: the waitqueue to wait on
 487  * @condition: a C expression for the event to wait for
 488  * @timeout: timeout, in jiffies
 489  *
 490  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 491  * @condition evaluates to true or a signal is received.
 492  * The @condition is checked each time the waitqueue @wq_head is woken up.
 493  *
 494  * wake_up() has to be called after changing any variable that could
 495  * change the result of the wait condition.
 496  *
 497  * Returns:
 498  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 499  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 500  * the remaining jiffies (at least 1) if the @condition evaluated
 501  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
 502  * interrupted by a signal.
 503  */
 504 #define wait_event_interruptible_timeout(wq_head, condition, timeout)           \
 505 ({                                                                              \
 506         long __ret = timeout;                                                   \
 507         might_sleep();                                                          \
 508         if (!___wait_cond_timeout(condition))                                   \
 509                 __ret = __wait_event_interruptible_timeout(wq_head,             \
 510                                                 condition, timeout);            \
 511         __ret;                                                                  \
 512 })
 513
 514 #define __wait_event_hrtimeout(wq_head, condition, timeout, state)              \
 515 ({                                                                              \
 516         int __ret = 0;                                                          \
 517         struct hrtimer_sleeper __t;                                             \
 518                                                                                 \
 519         hrtimer_init_sleeper_on_stack(&__t, CLOCK_MONOTONIC,                    \
 520                                       HRTIMER_MODE_REL);                        \
 521         if ((timeout) != KTIME_MAX)                                             \
 522                 hrtimer_start_range_ns(&__t.timer, timeout,                     \
 523                                        current->timer_slack_ns,                 \
 524                                        HRTIMER_MODE_REL);                       \
 525                                                                                 \
 526         __ret = ___wait_event(wq_head, condition, state, 0, 0,                  \
 527                 if (!__t.task) {                                                \
 528                         __ret = -ETIME;                                         \
 529                         break;                                                  \
 530                 }                                                               \
 531                 schedule());                                                    \
 532                                                                                 \
 533         hrtimer_cancel(&__t.timer);                                             \
 534         destroy_hrtimer_on_stack(&__t.timer);                                   \
 535         __ret;                                                                  \
 536 })
 537
 538 /**
 539  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
 540  * @wq_head: the waitqueue to wait on
 541  * @condition: a C expression for the event to wait for
 542  * @timeout: timeout, as a ktime_t
 543  *
 544  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 545  * @condition evaluates to true or a signal is received.
 546  * The @condition is checked each time the waitqueue @wq_head is woken up.
 547  *
 548  * wake_up() has to be called after changing any variable that could
 549  * change the result of the wait condition.
 550  *
 551  * The function returns 0 if @condition became true, or -ETIME if the timeout
 552  * elapsed.
 553  */
 554 #define wait_event_hrtimeout(wq_head, condition, timeout)                       \
 555 ({                                                                              \
 556         int __ret = 0;                                                          \
 557         might_sleep();                                                          \
 558         if (!(condition))                                                       \
 559                 __ret = __wait_event_hrtimeout(wq_head, condition, timeout,     \
 560                                                TASK_UNINTERRUPTIBLE);           \
 561         __ret;                                                                  \
 562 })
 563
 564 /**
 565  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
 566  * @wq: the waitqueue to wait on
 567  * @condition: a C expression for the event to wait for
 568  * @timeout: timeout, as a ktime_t
 569  *
 570  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 571  * @condition evaluates to true or a signal is received.
 572  * The @condition is checked each time the waitqueue @wq is woken up.
 573  *
 574  * wake_up() has to be called after changing any variable that could
 575  * change the result of the wait condition.
 576  *
 577  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
 578  * interrupted by a signal, or -ETIME if the timeout elapsed.
 579  */
 580 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)              \
 581 ({                                                                              \
 582         long __ret = 0;                                                         \
 583         might_sleep();                                                          \
 584         if (!(condition))                                                       \
 585                 __ret = __wait_event_hrtimeout(wq, condition, timeout,          \
 586                                                TASK_INTERRUPTIBLE);             \
 587         __ret;                                                                  \
 588 })
 589
 590 #define __wait_event_interruptible_exclusive(wq, condition)                     \
 591         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,                  \
 592                       schedule())
 593
 594 #define wait_event_interruptible_exclusive(wq, condition)                       \
 595 ({                                                                              \
 596         int __ret = 0;                                                          \
 597         might_sleep();                                                          \
 598         if (!(condition))                                                       \
 599                 __ret = __wait_event_interruptible_exclusive(wq, condition);    \
 600         __ret;                                                                  \
 601 })
 602
 603 #define __wait_event_killable_exclusive(wq, condition)                          \
 604         ___wait_event(wq, condition, TASK_KILLABLE, 1, 0,                       \
 605                       schedule())
 606
 607 #define wait_event_killable_exclusive(wq, condition)                            \
 608 ({                                                                              \
 609         int __ret = 0;                                                          \
 610         might_sleep();                                                          \
 611         if (!(condition))                                                       \
 612                 __ret = __wait_event_killable_exclusive(wq, condition);         \
 613         __ret;                                                                  \
 614 })
 615
 616
 617 #define __wait_event_freezable_exclusive(wq, condition)                         \
 618         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,                  \
 619                         freezable_schedule())
 620
 621 #define wait_event_freezable_exclusive(wq, condition)                           \
 622 ({                                                                              \
 623         int __ret = 0;                                                          \
 624         might_sleep();                                                          \
 625         if (!(condition))                                                       \
 626                 __ret = __wait_event_freezable_exclusive(wq, condition);        \
 627         __ret;                                                                  \
 628 })
 629
 630 /**
 631  * wait_event_idle - wait for a condition without contributing to system load
 632  * @wq_head: the waitqueue to wait on
 633  * @condition: a C expression for the event to wait for
 634  *
 635  * The process is put to sleep (TASK_IDLE) until the
 636  * @condition evaluates to true.
 637  * The @condition is checked each time the waitqueue @wq_head is woken up.
 638  *
 639  * wake_up() has to be called after changing any variable that could
 640  * change the result of the wait condition.
 641  *
 642  */
 643 #define wait_event_idle(wq_head, condition)                                     \
 644 do {                                                                            \
 645         might_sleep();                                                          \
 646         if (!(condition))                                                       \
 647                 ___wait_event(wq_head, condition, TASK_IDLE, 0, 0, schedule()); \
 648 } while (0)
 649
 650 /**
 651  * wait_event_idle_exclusive - wait for a condition with contributing to system load
 652  * @wq_head: the waitqueue to wait on
 653  * @condition: a C expression for the event to wait for
 654  *
 655  * The process is put to sleep (TASK_IDLE) until the
 656  * @condition evaluates to true.
 657  * The @condition is checked each time the waitqueue @wq_head is woken up.
 658  *
 659  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 660  * set thus if other processes wait on the same list, when this
 661  * process is woken further processes are not considered.
 662  *
 663  * wake_up() has to be called after changing any variable that could
 664  * change the result of the wait condition.
 665  *
 666  */
 667 #define wait_event_idle_exclusive(wq_head, condition)                           \
 668 do {                                                                            \
 669         might_sleep();                                                          \
 670         if (!(condition))                                                       \
 671                 ___wait_event(wq_head, condition, TASK_IDLE, 1, 0, schedule()); \
 672 } while (0)
 673
 674 #define __wait_event_idle_timeout(wq_head, condition, timeout)                  \
 675         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 676                       TASK_IDLE, 0, timeout,                                    \
 677                       __ret = schedule_timeout(__ret))
 678
 679 /**
 680  * wait_event_idle_timeout - sleep without load until a condition becomes true or a timeout elapses
 681  * @wq_head: the waitqueue to wait on
 682  * @condition: a C expression for the event to wait for
 683  * @timeout: timeout, in jiffies
 684  *
 685  * The process is put to sleep (TASK_IDLE) until the
 686  * @condition evaluates to true. The @condition is checked each time
 687  * the waitqueue @wq_head is woken up.
 688  *
 689  * wake_up() has to be called after changing any variable that could
 690  * change the result of the wait condition.
 691  *
 692  * Returns:
 693  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 694  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 695  * or the remaining jiffies (at least 1) if the @condition evaluated
 696  * to %true before the @timeout elapsed.
 697  */
 698 #define wait_event_idle_timeout(wq_head, condition, timeout)                    \
 699 ({                                                                              \
 700         long __ret = timeout;                                                   \
 701         might_sleep();                                                          \
 702         if (!___wait_cond_timeout(condition))                                   \
 703                 __ret = __wait_event_idle_timeout(wq_head, condition, timeout); \
 704         __ret;                                                                  \
 705 })
 706
 707 #define __wait_event_idle_exclusive_timeout(wq_head, condition, timeout)        \
 708         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 709                       TASK_IDLE, 1, timeout,                                    \
 710                       __ret = schedule_timeout(__ret))
 711
 712 /**
 713  * wait_event_idle_exclusive_timeout - sleep without load until a condition becomes true or a timeout elapses
 714  * @wq_head: the waitqueue to wait on
 715  * @condition: a C expression for the event to wait for
 716  * @timeout: timeout, in jiffies
 717  *
 718  * The process is put to sleep (TASK_IDLE) until the
 719  * @condition evaluates to true. The @condition is checked each time
 720  * the waitqueue @wq_head is woken up.
 721  *
 722  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 723  * set thus if other processes wait on the same list, when this
 724  * process is woken further processes are not considered.
 725  *
 726  * wake_up() has to be called after changing any variable that could
 727  * change the result of the wait condition.
 728  *
 729  * Returns:
 730  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 731  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 732  * or the remaining jiffies (at least 1) if the @condition evaluated
 733  * to %true before the @timeout elapsed.
 734  */
 735 #define wait_event_idle_exclusive_timeout(wq_head, condition, timeout)          \
 736 ({                                                                              \
 737         long __ret = timeout;                                                   \
 738         might_sleep();                                                          \
 739         if (!___wait_cond_timeout(condition))                                   \
 740                 __ret = __wait_event_idle_exclusive_timeout(wq_head, condition, timeout);\
 741         __ret;                                                                  \
 742 })
 743
 744 extern int do_wait_intr(wait_queue_head_t *, wait_queue_entry_t *);
 745 extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *);
 746
 747 #define __wait_event_interruptible_locked(wq, condition, exclusive, fn)         \
 748 ({                                                                              \
 749         int __ret;                                                              \
 750         DEFINE_WAIT(__wait);                                                    \
 751         if (exclusive)                                                          \
 752                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                              \
 753         do {                                                                    \
 754                 __ret = fn(&(wq), &__wait);                                     \
 755                 if (__ret)                                                      \
 756                         break;                                                  \
 757         } while (!(condition));                                                 \
 758         __remove_wait_queue(&(wq), &__wait);                                    \
 759         __set_current_state(TASK_RUNNING);                                      \
 760         __ret;                                                                  \
 761 })
 762
 763
 764 /**
 765  * wait_event_interruptible_locked - sleep until a condition gets true
 766  * @wq: the waitqueue to wait on
 767  * @condition: a C expression for the event to wait for
 768  *
 769  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 770  * @condition evaluates to true or a signal is received.
 771  * The @condition is checked each time the waitqueue @wq is woken up.
 772  *
 773  * It must be called with wq.lock being held.  This spinlock is
 774  * unlocked while sleeping but @condition testing is done while lock
 775  * is held and when this macro exits the lock is held.
 776  *
 777  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 778  * functions which must match the way they are locked/unlocked outside
 779  * of this macro.
 780  *
 781  * wake_up_locked() has to be called after changing any variable that could
 782  * change the result of the wait condition.
 783  *
 784  * The function will return -ERESTARTSYS if it was interrupted by a
 785  * signal and 0 if @condition evaluated to true.
 786  */
 787 #define wait_event_interruptible_locked(wq, condition)                          \
 788         ((condition)                                                            \
 789          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr))
 790
 791 /**
 792  * wait_event_interruptible_locked_irq - sleep until a condition gets true
 793  * @wq: the waitqueue to wait on
 794  * @condition: a C expression for the event to wait for
 795  *
 796  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 797  * @condition evaluates to true or a signal is received.
 798  * The @condition is checked each time the waitqueue @wq is woken up.
 799  *
 800  * It must be called with wq.lock being held.  This spinlock is
 801  * unlocked while sleeping but @condition testing is done while lock
 802  * is held and when this macro exits the lock is held.
 803  *
 804  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 805  * functions which must match the way they are locked/unlocked outside
 806  * of this macro.
 807  *
 808  * wake_up_locked() has to be called after changing any variable that could
 809  * change the result of the wait condition.
 810  *
 811  * The function will return -ERESTARTSYS if it was interrupted by a
 812  * signal and 0 if @condition evaluated to true.
 813  */
 814 #define wait_event_interruptible_locked_irq(wq, condition)                      \
 815         ((condition)                                                            \
 816          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr_irq))
 817
 818 /**
 819  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
 820  * @wq: the waitqueue to wait on
 821  * @condition: a C expression for the event to wait for
 822  *
 823  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 824  * @condition evaluates to true or a signal is received.
 825  * The @condition is checked each time the waitqueue @wq is woken up.
 826  *
 827  * It must be called with wq.lock being held.  This spinlock is
 828  * unlocked while sleeping but @condition testing is done while lock
 829  * is held and when this macro exits the lock is held.
 830  *
 831  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 832  * functions which must match the way they are locked/unlocked outside
 833  * of this macro.
 834  *
 835  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 836  * set thus when other process waits process on the list if this
 837  * process is awaken further processes are not considered.
 838  *
 839  * wake_up_locked() has to be called after changing any variable that could
 840  * change the result of the wait condition.
 841  *
 842  * The function will return -ERESTARTSYS if it was interrupted by a
 843  * signal and 0 if @condition evaluated to true.
 844  */
 845 #define wait_event_interruptible_exclusive_locked(wq, condition)                \
 846         ((condition)                                                            \
 847          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr))
 848
 849 /**
 850  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
 851  * @wq: the waitqueue to wait on
 852  * @condition: a C expression for the event to wait for
 853  *
 854  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 855  * @condition evaluates to true or a signal is received.
 856  * The @condition is checked each time the waitqueue @wq is woken up.
 857  *
 858  * It must be called with wq.lock being held.  This spinlock is
 859  * unlocked while sleeping but @condition testing is done while lock
 860  * is held and when this macro exits the lock is held.
 861  *
 862  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 863  * functions which must match the way they are locked/unlocked outside
 864  * of this macro.
 865  *
 866  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 867  * set thus when other process waits process on the list if this
 868  * process is awaken further processes are not considered.
 869  *
 870  * wake_up_locked() has to be called after changing any variable that could
 871  * change the result of the wait condition.
 872  *
 873  * The function will return -ERESTARTSYS if it was interrupted by a
 874  * signal and 0 if @condition evaluated to true.
 875  */
 876 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)            \
 877         ((condition)                                                            \
 878          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr_irq))
 879
 880
 881 #define __wait_event_killable(wq, condition)                                    \
 882         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
 883
 884 /**
 885  * wait_event_killable - sleep until a condition gets true
 886  * @wq_head: the waitqueue to wait on
 887  * @condition: a C expression for the event to wait for
 888  *
 889  * The process is put to sleep (TASK_KILLABLE) until the
 890  * @condition evaluates to true or a signal is received.
 891  * The @condition is checked each time the waitqueue @wq_head is woken up.
 892  *
 893  * wake_up() has to be called after changing any variable that could
 894  * change the result of the wait condition.
 895  *
 896  * The function will return -ERESTARTSYS if it was interrupted by a
 897  * signal and 0 if @condition evaluated to true.
 898  */
 899 #define wait_event_killable(wq_head, condition)                                 \
 900 ({                                                                              \
 901         int __ret = 0;                                                          \
 902         might_sleep();                                                          \
 903         if (!(condition))                                                       \
 904                 __ret = __wait_event_killable(wq_head, condition);              \
 905         __ret;                                                                  \
 906 })
 907
 908 #define __wait_event_killable_timeout(wq_head, condition, timeout)              \
 909         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 910                       TASK_KILLABLE, 0, timeout,                                \
 911                       __ret = schedule_timeout(__ret))
 912
 913 /**
 914  * wait_event_killable_timeout - sleep until a condition gets true or a timeout elapses
 915  * @wq_head: the waitqueue to wait on
 916  * @condition: a C expression for the event to wait for
 917  * @timeout: timeout, in jiffies
 918  *
 919  * The process is put to sleep (TASK_KILLABLE) until the
 920  * @condition evaluates to true or a kill signal is received.
 921  * The @condition is checked each time the waitqueue @wq_head is woken up.
 922  *
 923  * wake_up() has to be called after changing any variable that could
 924  * change the result of the wait condition.
 925  *
 926  * Returns:
 927  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 928  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 929  * the remaining jiffies (at least 1) if the @condition evaluated
 930  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
 931  * interrupted by a kill signal.
 932  *
 933  * Only kill signals interrupt this process.
 934  */
 935 #define wait_event_killable_timeout(wq_head, condition, timeout)                \
 936 ({                                                                              \
 937         long __ret = timeout;                                                   \
 938         might_sleep();                                                          \
 939         if (!___wait_cond_timeout(condition))                                   \
 940                 __ret = __wait_event_killable_timeout(wq_head,                  \
 941                                                 condition, timeout);            \
 942         __ret;                                                                  \
 943 })
 944
 945
 946 #define __wait_event_lock_irq(wq_head, condition, lock, cmd)                    \
 947         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
 948                             spin_unlock_irq(&lock);                             \
 949                             cmd;                                                \
 950                             schedule();                                         \
 951                             spin_lock_irq(&lock))
 952
 953 /**
 954  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
 955  *                           condition is checked under the lock. This
 956  *                           is expected to be called with the lock
 957  *                           taken.
 958  * @wq_head: the waitqueue to wait on
 959  * @condition: a C expression for the event to wait for
 960  * @lock: a locked spinlock_t, which will be released before cmd
 961  *        and schedule() and reacquired afterwards.
 962  * @cmd: a command which is invoked outside the critical section before
 963  *       sleep
 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 invoking the cmd and going to sleep and is reacquired
 974  * afterwards.
 975  */
 976 #define wait_event_lock_irq_cmd(wq_head, condition, lock, cmd)                  \
 977 do {                                                                            \
 978         if (condition)                                                          \
 979                 break;                                                          \
 980         __wait_event_lock_irq(wq_head, condition, lock, cmd);                   \
 981 } while (0)
 982
 983 /**
 984  * wait_event_lock_irq - sleep until a condition gets true. The
 985  *                       condition is checked under the lock. This
 986  *                       is expected to be called with the lock
 987  *                       taken.
 988  * @wq_head: the waitqueue to wait on
 989  * @condition: a C expression for the event to wait for
 990  * @lock: a locked spinlock_t, which will be released before schedule()
 991  *        and reacquired afterwards.
 992  *
 993  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 994  * @condition evaluates to true. The @condition is checked each time
 995  * the waitqueue @wq_head is woken up.
 996  *
 997  * wake_up() has to be called after changing any variable that could
 998  * change the result of the wait condition.
 999  *
1000  * This is supposed to be called while holding the lock. The lock is
1001  * dropped before going to sleep and is reacquired afterwards.
1002  */
1003 #define wait_event_lock_irq(wq_head, condition, lock)                           \
1004 do {                                                                            \
1005         if (condition)                                                          \
1006                 break;                                                          \
1007         __wait_event_lock_irq(wq_head, condition, lock, );                      \
1008 } while (0)
1009
1010
1011 #define __wait_event_interruptible_lock_irq(wq_head, condition, lock, cmd)      \
1012         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
1013                       spin_unlock_irq(&lock);                                   \
1014                       cmd;                                                      \
1015                       schedule();                                               \
1016                       spin_lock_irq(&lock))
1017
1018 /**
1019  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
1020  *              The condition is checked under the lock. This is expected to
1021  *              be called with the lock taken.
1022  * @wq_head: the waitqueue to wait on
1023  * @condition: a C expression for the event to wait for
1024  * @lock: a locked spinlock_t, which will be released before cmd and
1025  *        schedule() and reacquired afterwards.
1026  * @cmd: a command which is invoked outside the critical section before
1027  *       sleep
1028  *
1029  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1030  * @condition evaluates to true or a signal is received. The @condition is
1031  * checked each time the waitqueue @wq_head is woken up.
1032  *
1033  * wake_up() has to be called after changing any variable that could
1034  * change the result of the wait condition.
1035  *
1036  * This is supposed to be called while holding the lock. The lock is
1037  * dropped before invoking the cmd and going to sleep and is reacquired
1038  * afterwards.
1039  *
1040  * The macro will return -ERESTARTSYS if it was interrupted by a signal
1041  * and 0 if @condition evaluated to true.
1042  */
1043 #define wait_event_interruptible_lock_irq_cmd(wq_head, condition, lock, cmd)    \
1044 ({                                                                              \
1045         int __ret = 0;                                                          \
1046         if (!(condition))                                                       \
1047                 __ret = __wait_event_interruptible_lock_irq(wq_head,            \
1048                                                 condition, lock, cmd);          \
1049         __ret;                                                                  \
1050 })
1051
1052 /**
1053  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
1054  *              The condition is checked under the lock. This is expected
1055  *              to be called with the lock taken.
1056  * @wq_head: the waitqueue to wait on
1057  * @condition: a C expression for the event to wait for
1058  * @lock: a locked spinlock_t, which will be released before schedule()
1059  *        and reacquired afterwards.
1060  *
1061  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1062  * @condition evaluates to true or signal is received. The @condition is
1063  * checked each time the waitqueue @wq_head is woken up.
1064  *
1065  * wake_up() has to be called after changing any variable that could
1066  * change the result of the wait condition.
1067  *
1068  * This is supposed to be called while holding the lock. The lock is
1069  * dropped before going to sleep and is reacquired afterwards.
1070  *
1071  * The macro will return -ERESTARTSYS if it was interrupted by a signal
1072  * and 0 if @condition evaluated to true.
1073  */
1074 #define wait_event_interruptible_lock_irq(wq_head, condition, lock)             \
1075 ({                                                                              \
1076         int __ret = 0;                                                          \
1077         if (!(condition))                                                       \
1078                 __ret = __wait_event_interruptible_lock_irq(wq_head,            \
1079                                                 condition, lock,);              \
1080         __ret;                                                                  \
1081 })
1082
1083 #define __wait_event_lock_irq_timeout(wq_head, condition, lock, timeout, state) \
1084         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
1085                       state, 0, timeout,                                        \
1086                       spin_unlock_irq(&lock);                                   \
1087                       __ret = schedule_timeout(__ret);                          \
1088                       spin_lock_irq(&lock));
1089
1090 /**
1091  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
1092  *              true or a timeout elapses. The condition is checked under
1093  *              the lock. This is expected to be called with the lock taken.
1094  * @wq_head: the waitqueue to wait on
1095  * @condition: a C expression for the event to wait for
1096  * @lock: a locked spinlock_t, which will be released before schedule()
1097  *        and reacquired afterwards.
1098  * @timeout: timeout, in jiffies
1099  *
1100  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1101  * @condition evaluates to true or signal is received. The @condition is
1102  * checked each time the waitqueue @wq_head is woken up.
1103  *
1104  * wake_up() has to be called after changing any variable that could
1105  * change the result of the wait condition.
1106  *
1107  * This is supposed to be called while holding the lock. The lock is
1108  * dropped before going to sleep and is reacquired afterwards.
1109  *
1110  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
1111  * was interrupted by a signal, and the remaining jiffies otherwise
1112  * if the condition evaluated to true before the timeout elapsed.
1113  */
1114 #define wait_event_interruptible_lock_irq_timeout(wq_head, condition, lock,     \
1115                                                   timeout)                      \
1116 ({                                                                              \
1117         long __ret = timeout;                                                   \
1118         if (!___wait_cond_timeout(condition))                                   \
1119                 __ret = __wait_event_lock_irq_timeout(                          \
1120                                         wq_head, condition, lock, timeout,      \
1121                                         TASK_INTERRUPTIBLE);                    \
1122         __ret;                                                                  \
1123 })
1124
1125 #define wait_event_lock_irq_timeout(wq_head, condition, lock, timeout)          \
1126 ({                                                                              \
1127         long __ret = timeout;                                                   \
1128         if (!___wait_cond_timeout(condition))                                   \
1129                 __ret = __wait_event_lock_irq_timeout(                          \
1130                                         wq_head, condition, lock, timeout,      \
1131                                         TASK_UNINTERRUPTIBLE);                  \
1132         __ret;                                                                  \
1133 })
1134
1135 /*
1136  * Waitqueues which are removed from the waitqueue_head at wakeup time
1137  */
1138 void prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1139 void prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1140 long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1141 void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
1142 long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout);
1143 int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
1144 int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
1145
1146 #define DEFINE_WAIT_FUNC(name, function)                                        \
1147         struct wait_queue_entry name = {                                        \
1148                 .private        = current,                                      \
1149                 .func           = function,                                     \
1150                 .entry          = LIST_HEAD_INIT((name).entry),                 \
1151         }
1152
1153 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
1154
1155 #define init_wait(wait)                                                         \
1156         do {                                                                    \
1157                 (wait)->private = current;                                      \
1158                 (wait)->func = autoremove_wake_function;                        \
1159                 INIT_LIST_HEAD(&(wait)->entry);                                 \
1160                 (wait)->flags = 0;                                              \
1161         } while (0)
1162
1163 bool try_invoke_on_locked_down_task(struct task_struct *p, bool (*func)(struct task_struct *t, void *arg), void *arg);
1164
1165 #endif /* _LINUX_WAIT_H */