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_single_sleeper - check if there is only one sleeper
 131  * @wq_head: wait queue head
 132  *
 133  * Returns true of wq_head has only one sleeper on the list.
 134  *
 135  * Please refer to the comment for waitqueue_active.
 136  */
 137 static inline bool wq_has_single_sleeper(struct wait_queue_head *wq_head)
 138 {
 139         return list_is_singular(&wq_head->head);
 140 }
 141
 142 /**
 143  * wq_has_sleeper - check if there are any waiting processes
 144  * @wq_head: wait queue head
 145  *
 146  * Returns true if wq_head has waiting processes
 147  *
 148  * Please refer to the comment for waitqueue_active.
 149  */
 150 static inline bool wq_has_sleeper(struct wait_queue_head *wq_head)
 151 {
 152         /*
 153          * We need to be sure we are in sync with the
 154          * add_wait_queue modifications to the wait queue.
 155          *
 156          * This memory barrier should be paired with one on the
 157          * waiting side.
 158          */
 159         smp_mb();
 160         return waitqueue_active(wq_head);
 161 }
 162
 163 extern void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
 164 extern void add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
 165 extern void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
 166
 167 static inline void __add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
 168 {
 169         list_add(&wq_entry->entry, &wq_head->head);
 170 }
 171
 172 /*
 173  * Used for wake-one threads:
 174  */
 175 static inline void
 176 __add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
 177 {
 178         wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
 179         __add_wait_queue(wq_head, wq_entry);
 180 }
 181
 182 static inline void __add_wait_queue_entry_tail(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
 183 {
 184         list_add_tail(&wq_entry->entry, &wq_head->head);
 185 }
 186
 187 static inline void
 188 __add_wait_queue_entry_tail_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_entry_tail(wq_head, wq_entry);
 192 }
 193
 194 static inline void
 195 __remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
 196 {
 197         list_del(&wq_entry->entry);
 198 }
 199
 200 void __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
 201 void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
 202 void __wake_up_locked_key_bookmark(struct wait_queue_head *wq_head,
 203                 unsigned int mode, void *key, wait_queue_entry_t *bookmark);
 204 void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
 205 void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr);
 206 void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode, int nr);
 207 void __wake_up_pollfree(struct wait_queue_head *wq_head);
 208
 209 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
 210 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
 211 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
 212 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL, 1)
 213 #define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)
 214
 215 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 216 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
 217 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
 218 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
 219
 220 /*
 221  * Wakeup macros to be used to report events to the targets.
 222  */
 223 #define poll_to_key(m) ((void *)(__force uintptr_t)(__poll_t)(m))
 224 #define key_to_poll(m) ((__force __poll_t)(uintptr_t)(void *)(m))
 225 #define wake_up_poll(x, m)                                                      \
 226         __wake_up(x, TASK_NORMAL, 1, poll_to_key(m))
 227 #define wake_up_locked_poll(x, m)                                               \
 228         __wake_up_locked_key((x), TASK_NORMAL, poll_to_key(m))
 229 #define wake_up_interruptible_poll(x, m)                                        \
 230         __wake_up(x, TASK_INTERRUPTIBLE, 1, poll_to_key(m))
 231 #define wake_up_interruptible_sync_poll(x, m)                                   \
 232         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, poll_to_key(m))
 233
 234 /**
 235  * wake_up_pollfree - signal that a polled waitqueue is going away
 236  * @wq_head: the wait queue head
 237  *
 238  * In the very rare cases where a ->poll() implementation uses a waitqueue whose
 239  * lifetime is tied to a task rather than to the 'struct file' being polled,
 240  * this function must be called before the waitqueue is freed so that
 241  * non-blocking polls (e.g. epoll) are notified that the queue is going away.
 242  *
 243  * The caller must also RCU-delay the freeing of the wait_queue_head, e.g. via
 244  * an explicit synchronize_rcu() or call_rcu(), or via SLAB_TYPESAFE_BY_RCU.
 245  */
 246 static inline void wake_up_pollfree(struct wait_queue_head *wq_head)
 247 {
 248         /*
 249          * For performance reasons, we don't always take the queue lock here.
 250          * Therefore, we might race with someone removing the last entry from
 251          * the queue, and proceed while they still hold the queue lock.
 252          * However, rcu_read_lock() is required to be held in such cases, so we
 253          * can safely proceed with an RCU-delayed free.
 254          */
 255         if (waitqueue_active(wq_head))
 256                 __wake_up_pollfree(wq_head);
 257 }
 258
 259 #define ___wait_cond_timeout(condition)                                         \
 260 ({                                                                              \
 261         bool __cond = (condition);                                              \
 262         if (__cond && !__ret)                                                   \
 263                 __ret = 1;                                                      \
 264         __cond || !__ret;                                                       \
 265 })
 266
 267 #define ___wait_is_interruptible(state)                                         \
 268         (!__builtin_constant_p(state) ||                                        \
 269                 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE)          \
 270
 271 extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags);
 272
 273 /*
 274  * The below macro ___wait_event() has an explicit shadow of the __ret
 275  * variable when used from the wait_event_*() macros.
 276  *
 277  * This is so that both can use the ___wait_cond_timeout() construct
 278  * to wrap the condition.
 279  *
 280  * The type inconsistency of the wait_event_*() __ret variable is also
 281  * on purpose; we use long where we can return timeout values and int
 282  * otherwise.
 283  */
 284
 285 #define ___wait_event(wq_head, condition, state, exclusive, ret, cmd)           \
 286 ({                                                                              \
 287         __label__ __out;                                                        \
 288         struct wait_queue_entry __wq_entry;                                     \
 289         long __ret = ret;       /* explicit shadow */                           \
 290                                                                                 \
 291         init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0);        \
 292         for (;;) {                                                              \
 293                 long __int = prepare_to_wait_event(&wq_head, &__wq_entry, state);\
 294                                                                                 \
 295                 if (condition)                                                  \
 296                         break;                                                  \
 297                                                                                 \
 298                 if (___wait_is_interruptible(state) && __int) {                 \
 299                         __ret = __int;                                          \
 300                         goto __out;                                             \
 301                 }                                                               \
 302                                                                                 \
 303                 cmd;                                                            \
 304         }                                                                       \
 305         finish_wait(&wq_head, &__wq_entry);                                     \
 306 __out:  __ret;                                                                  \
 307 })
 308
 309 #define __wait_event(wq_head, condition)                                        \
 310         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
 311                             schedule())
 312
 313 /**
 314  * wait_event - sleep until a condition gets true
 315  * @wq_head: the waitqueue to wait on
 316  * @condition: a C expression for the event to wait for
 317  *
 318  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 319  * @condition evaluates to true. The @condition is checked each time
 320  * the waitqueue @wq_head is woken up.
 321  *
 322  * wake_up() has to be called after changing any variable that could
 323  * change the result of the wait condition.
 324  */
 325 #define wait_event(wq_head, condition)                                          \
 326 do {                                                                            \
 327         might_sleep();                                                          \
 328         if (condition)                                                          \
 329                 break;                                                          \
 330         __wait_event(wq_head, condition);                                       \
 331 } while (0)
 332
 333 #define __io_wait_event(wq_head, condition)                                     \
 334         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
 335                             io_schedule())
 336
 337 /*
 338  * io_wait_event() -- like wait_event() but with io_schedule()
 339  */
 340 #define io_wait_event(wq_head, condition)                                       \
 341 do {                                                                            \
 342         might_sleep();                                                          \
 343         if (condition)                                                          \
 344                 break;                                                          \
 345         __io_wait_event(wq_head, condition);                                    \
 346 } while (0)
 347
 348 #define __wait_event_freezable(wq_head, condition)                              \
 349         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
 350                             freezable_schedule())
 351
 352 /**
 353  * wait_event_freezable - sleep (or freeze) until a condition gets true
 354  * @wq_head: the waitqueue to wait on
 355  * @condition: a C expression for the event to wait for
 356  *
 357  * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
 358  * to system load) until the @condition evaluates to true. The
 359  * @condition is checked each time the waitqueue @wq_head is woken up.
 360  *
 361  * wake_up() has to be called after changing any variable that could
 362  * change the result of the wait condition.
 363  */
 364 #define wait_event_freezable(wq_head, condition)                                \
 365 ({                                                                              \
 366         int __ret = 0;                                                          \
 367         might_sleep();                                                          \
 368         if (!(condition))                                                       \
 369                 __ret = __wait_event_freezable(wq_head, condition);             \
 370         __ret;                                                                  \
 371 })
 372
 373 #define __wait_event_timeout(wq_head, condition, timeout)                       \
 374         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 375                       TASK_UNINTERRUPTIBLE, 0, timeout,                         \
 376                       __ret = schedule_timeout(__ret))
 377
 378 /**
 379  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 380  * @wq_head: the waitqueue to wait on
 381  * @condition: a C expression for the event to wait for
 382  * @timeout: timeout, in jiffies
 383  *
 384  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 385  * @condition evaluates to true. The @condition is checked each time
 386  * the waitqueue @wq_head is woken up.
 387  *
 388  * wake_up() has to be called after changing any variable that could
 389  * change the result of the wait condition.
 390  *
 391  * Returns:
 392  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 393  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 394  * or the remaining jiffies (at least 1) if the @condition evaluated
 395  * to %true before the @timeout elapsed.
 396  */
 397 #define wait_event_timeout(wq_head, condition, timeout)                         \
 398 ({                                                                              \
 399         long __ret = timeout;                                                   \
 400         might_sleep();                                                          \
 401         if (!___wait_cond_timeout(condition))                                   \
 402                 __ret = __wait_event_timeout(wq_head, condition, timeout);      \
 403         __ret;                                                                  \
 404 })
 405
 406 #define __wait_event_freezable_timeout(wq_head, condition, timeout)             \
 407         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 408                       TASK_INTERRUPTIBLE, 0, timeout,                           \
 409                       __ret = freezable_schedule_timeout(__ret))
 410
 411 /*
 412  * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
 413  * increasing load and is freezable.
 414  */
 415 #define wait_event_freezable_timeout(wq_head, condition, timeout)               \
 416 ({                                                                              \
 417         long __ret = timeout;                                                   \
 418         might_sleep();                                                          \
 419         if (!___wait_cond_timeout(condition))                                   \
 420                 __ret = __wait_event_freezable_timeout(wq_head, condition, timeout); \
 421         __ret;                                                                  \
 422 })
 423
 424 #define __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2)              \
 425         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 1, 0,     \
 426                             cmd1; schedule(); cmd2)
 427 /*
 428  * Just like wait_event_cmd(), except it sets exclusive flag
 429  */
 430 #define wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2)                \
 431 do {                                                                            \
 432         if (condition)                                                          \
 433                 break;                                                          \
 434         __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2);             \
 435 } while (0)
 436
 437 #define __wait_event_cmd(wq_head, condition, cmd1, cmd2)                        \
 438         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
 439                             cmd1; schedule(); cmd2)
 440
 441 /**
 442  * wait_event_cmd - sleep until a condition gets true
 443  * @wq_head: the waitqueue to wait on
 444  * @condition: a C expression for the event to wait for
 445  * @cmd1: the command will be executed before sleep
 446  * @cmd2: the command will be executed after sleep
 447  *
 448  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 449  * @condition evaluates to true. The @condition is checked each time
 450  * the waitqueue @wq_head is woken up.
 451  *
 452  * wake_up() has to be called after changing any variable that could
 453  * change the result of the wait condition.
 454  */
 455 #define wait_event_cmd(wq_head, condition, cmd1, cmd2)                          \
 456 do {                                                                            \
 457         if (condition)                                                          \
 458                 break;                                                          \
 459         __wait_event_cmd(wq_head, condition, cmd1, cmd2);                       \
 460 } while (0)
 461
 462 #define __wait_event_interruptible(wq_head, condition)                          \
 463         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
 464                       schedule())
 465
 466 /**
 467  * wait_event_interruptible - sleep until a condition gets true
 468  * @wq_head: the waitqueue to wait on
 469  * @condition: a C expression for the event to wait for
 470  *
 471  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 472  * @condition evaluates to true or a signal is received.
 473  * The @condition is checked each time the waitqueue @wq_head is woken up.
 474  *
 475  * wake_up() has to be called after changing any variable that could
 476  * change the result of the wait condition.
 477  *
 478  * The function will return -ERESTARTSYS if it was interrupted by a
 479  * signal and 0 if @condition evaluated to true.
 480  */
 481 #define wait_event_interruptible(wq_head, condition)                            \
 482 ({                                                                              \
 483         int __ret = 0;                                                          \
 484         might_sleep();                                                          \
 485         if (!(condition))                                                       \
 486                 __ret = __wait_event_interruptible(wq_head, condition);         \
 487         __ret;                                                                  \
 488 })
 489
 490 #define __wait_event_interruptible_timeout(wq_head, condition, timeout)         \
 491         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 492                       TASK_INTERRUPTIBLE, 0, timeout,                           \
 493                       __ret = schedule_timeout(__ret))
 494
 495 /**
 496  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 497  * @wq_head: the waitqueue to wait on
 498  * @condition: a C expression for the event to wait for
 499  * @timeout: timeout, in jiffies
 500  *
 501  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 502  * @condition evaluates to true or a signal is received.
 503  * The @condition is checked each time the waitqueue @wq_head is woken up.
 504  *
 505  * wake_up() has to be called after changing any variable that could
 506  * change the result of the wait condition.
 507  *
 508  * Returns:
 509  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 510  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 511  * the remaining jiffies (at least 1) if the @condition evaluated
 512  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
 513  * interrupted by a signal.
 514  */
 515 #define wait_event_interruptible_timeout(wq_head, condition, timeout)           \
 516 ({                                                                              \
 517         long __ret = timeout;                                                   \
 518         might_sleep();                                                          \
 519         if (!___wait_cond_timeout(condition))                                   \
 520                 __ret = __wait_event_interruptible_timeout(wq_head,             \
 521                                                 condition, timeout);            \
 522         __ret;                                                                  \
 523 })
 524
 525 #define __wait_event_hrtimeout(wq_head, condition, timeout, state)              \
 526 ({                                                                              \
 527         int __ret = 0;                                                          \
 528         struct hrtimer_sleeper __t;                                             \
 529                                                                                 \
 530         hrtimer_init_sleeper_on_stack(&__t, CLOCK_MONOTONIC,                    \
 531                                       HRTIMER_MODE_REL);                        \
 532         if ((timeout) != KTIME_MAX) {                                           \
 533                 hrtimer_set_expires_range_ns(&__t.timer, timeout,               \
 534                                         current->timer_slack_ns);               \
 535                 hrtimer_sleeper_start_expires(&__t, HRTIMER_MODE_REL);          \
 536         }                                                                       \
 537                                                                                 \
 538         __ret = ___wait_event(wq_head, condition, state, 0, 0,                  \
 539                 if (!__t.task) {                                                \
 540                         __ret = -ETIME;                                         \
 541                         break;                                                  \
 542                 }                                                               \
 543                 schedule());                                                    \
 544                                                                                 \
 545         hrtimer_cancel(&__t.timer);                                             \
 546         destroy_hrtimer_on_stack(&__t.timer);                                   \
 547         __ret;                                                                  \
 548 })
 549
 550 /**
 551  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
 552  * @wq_head: the waitqueue to wait on
 553  * @condition: a C expression for the event to wait for
 554  * @timeout: timeout, as a ktime_t
 555  *
 556  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 557  * @condition evaluates to true or a signal is received.
 558  * The @condition is checked each time the waitqueue @wq_head is woken up.
 559  *
 560  * wake_up() has to be called after changing any variable that could
 561  * change the result of the wait condition.
 562  *
 563  * The function returns 0 if @condition became true, or -ETIME if the timeout
 564  * elapsed.
 565  */
 566 #define wait_event_hrtimeout(wq_head, condition, timeout)                       \
 567 ({                                                                              \
 568         int __ret = 0;                                                          \
 569         might_sleep();                                                          \
 570         if (!(condition))                                                       \
 571                 __ret = __wait_event_hrtimeout(wq_head, condition, timeout,     \
 572                                                TASK_UNINTERRUPTIBLE);           \
 573         __ret;                                                                  \
 574 })
 575
 576 /**
 577  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
 578  * @wq: the waitqueue to wait on
 579  * @condition: a C expression for the event to wait for
 580  * @timeout: timeout, as a ktime_t
 581  *
 582  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 583  * @condition evaluates to true or a signal is received.
 584  * The @condition is checked each time the waitqueue @wq is woken up.
 585  *
 586  * wake_up() has to be called after changing any variable that could
 587  * change the result of the wait condition.
 588  *
 589  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
 590  * interrupted by a signal, or -ETIME if the timeout elapsed.
 591  */
 592 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)              \
 593 ({                                                                              \
 594         long __ret = 0;                                                         \
 595         might_sleep();                                                          \
 596         if (!(condition))                                                       \
 597                 __ret = __wait_event_hrtimeout(wq, condition, timeout,          \
 598                                                TASK_INTERRUPTIBLE);             \
 599         __ret;                                                                  \
 600 })
 601
 602 #define __wait_event_interruptible_exclusive(wq, condition)                     \
 603         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,                  \
 604                       schedule())
 605
 606 #define wait_event_interruptible_exclusive(wq, condition)                       \
 607 ({                                                                              \
 608         int __ret = 0;                                                          \
 609         might_sleep();                                                          \
 610         if (!(condition))                                                       \
 611                 __ret = __wait_event_interruptible_exclusive(wq, condition);    \
 612         __ret;                                                                  \
 613 })
 614
 615 #define __wait_event_killable_exclusive(wq, condition)                          \
 616         ___wait_event(wq, condition, TASK_KILLABLE, 1, 0,                       \
 617                       schedule())
 618
 619 #define wait_event_killable_exclusive(wq, condition)                            \
 620 ({                                                                              \
 621         int __ret = 0;                                                          \
 622         might_sleep();                                                          \
 623         if (!(condition))                                                       \
 624                 __ret = __wait_event_killable_exclusive(wq, condition);         \
 625         __ret;                                                                  \
 626 })
 627
 628
 629 #define __wait_event_freezable_exclusive(wq, condition)                         \
 630         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,                  \
 631                         freezable_schedule())
 632
 633 #define wait_event_freezable_exclusive(wq, condition)                           \
 634 ({                                                                              \
 635         int __ret = 0;                                                          \
 636         might_sleep();                                                          \
 637         if (!(condition))                                                       \
 638                 __ret = __wait_event_freezable_exclusive(wq, condition);        \
 639         __ret;                                                                  \
 640 })
 641
 642 /**
 643  * wait_event_idle - wait for a condition without contributing to system load
 644  * @wq_head: the waitqueue to wait on
 645  * @condition: a C expression for the event to wait for
 646  *
 647  * The process is put to sleep (TASK_IDLE) until the
 648  * @condition evaluates to true.
 649  * The @condition is checked each time the waitqueue @wq_head is woken up.
 650  *
 651  * wake_up() has to be called after changing any variable that could
 652  * change the result of the wait condition.
 653  *
 654  */
 655 #define wait_event_idle(wq_head, condition)                                     \
 656 do {                                                                            \
 657         might_sleep();                                                          \
 658         if (!(condition))                                                       \
 659                 ___wait_event(wq_head, condition, TASK_IDLE, 0, 0, schedule()); \
 660 } while (0)
 661
 662 /**
 663  * wait_event_idle_exclusive - wait for a condition with contributing to system load
 664  * @wq_head: the waitqueue to wait on
 665  * @condition: a C expression for the event to wait for
 666  *
 667  * The process is put to sleep (TASK_IDLE) until the
 668  * @condition evaluates to true.
 669  * The @condition is checked each time the waitqueue @wq_head is woken up.
 670  *
 671  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 672  * set thus if other processes wait on the same list, when this
 673  * process is woken further processes are not considered.
 674  *
 675  * wake_up() has to be called after changing any variable that could
 676  * change the result of the wait condition.
 677  *
 678  */
 679 #define wait_event_idle_exclusive(wq_head, condition)                           \
 680 do {                                                                            \
 681         might_sleep();                                                          \
 682         if (!(condition))                                                       \
 683                 ___wait_event(wq_head, condition, TASK_IDLE, 1, 0, schedule()); \
 684 } while (0)
 685
 686 #define __wait_event_idle_timeout(wq_head, condition, timeout)                  \
 687         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 688                       TASK_IDLE, 0, timeout,                                    \
 689                       __ret = schedule_timeout(__ret))
 690
 691 /**
 692  * wait_event_idle_timeout - sleep without load until a condition becomes true or a timeout elapses
 693  * @wq_head: the waitqueue to wait on
 694  * @condition: a C expression for the event to wait for
 695  * @timeout: timeout, in jiffies
 696  *
 697  * The process is put to sleep (TASK_IDLE) until the
 698  * @condition evaluates to true. The @condition is checked each time
 699  * the waitqueue @wq_head is woken up.
 700  *
 701  * wake_up() has to be called after changing any variable that could
 702  * change the result of the wait condition.
 703  *
 704  * Returns:
 705  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 706  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 707  * or the remaining jiffies (at least 1) if the @condition evaluated
 708  * to %true before the @timeout elapsed.
 709  */
 710 #define wait_event_idle_timeout(wq_head, condition, timeout)                    \
 711 ({                                                                              \
 712         long __ret = timeout;                                                   \
 713         might_sleep();                                                          \
 714         if (!___wait_cond_timeout(condition))                                   \
 715                 __ret = __wait_event_idle_timeout(wq_head, condition, timeout); \
 716         __ret;                                                                  \
 717 })
 718
 719 #define __wait_event_idle_exclusive_timeout(wq_head, condition, timeout)        \
 720         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 721                       TASK_IDLE, 1, timeout,                                    \
 722                       __ret = schedule_timeout(__ret))
 723
 724 /**
 725  * wait_event_idle_exclusive_timeout - sleep without load until a condition becomes true or a timeout elapses
 726  * @wq_head: the waitqueue to wait on
 727  * @condition: a C expression for the event to wait for
 728  * @timeout: timeout, in jiffies
 729  *
 730  * The process is put to sleep (TASK_IDLE) until the
 731  * @condition evaluates to true. The @condition is checked each time
 732  * the waitqueue @wq_head is woken up.
 733  *
 734  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 735  * set thus if other processes wait on the same list, when this
 736  * process is woken further processes are not considered.
 737  *
 738  * wake_up() has to be called after changing any variable that could
 739  * change the result of the wait condition.
 740  *
 741  * Returns:
 742  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 743  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 744  * or the remaining jiffies (at least 1) if the @condition evaluated
 745  * to %true before the @timeout elapsed.
 746  */
 747 #define wait_event_idle_exclusive_timeout(wq_head, condition, timeout)          \
 748 ({                                                                              \
 749         long __ret = timeout;                                                   \
 750         might_sleep();                                                          \
 751         if (!___wait_cond_timeout(condition))                                   \
 752                 __ret = __wait_event_idle_exclusive_timeout(wq_head, condition, timeout);\
 753         __ret;                                                                  \
 754 })
 755
 756 extern int do_wait_intr(wait_queue_head_t *, wait_queue_entry_t *);
 757 extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *);
 758
 759 #define __wait_event_interruptible_locked(wq, condition, exclusive, fn)         \
 760 ({                                                                              \
 761         int __ret;                                                              \
 762         DEFINE_WAIT(__wait);                                                    \
 763         if (exclusive)                                                          \
 764                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                              \
 765         do {                                                                    \
 766                 __ret = fn(&(wq), &__wait);                                     \
 767                 if (__ret)                                                      \
 768                         break;                                                  \
 769         } while (!(condition));                                                 \
 770         __remove_wait_queue(&(wq), &__wait);                                    \
 771         __set_current_state(TASK_RUNNING);                                      \
 772         __ret;                                                                  \
 773 })
 774
 775
 776 /**
 777  * wait_event_interruptible_locked - sleep until a condition gets true
 778  * @wq: the waitqueue to wait on
 779  * @condition: a C expression for the event to wait for
 780  *
 781  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 782  * @condition evaluates to true or a signal is received.
 783  * The @condition is checked each time the waitqueue @wq is woken up.
 784  *
 785  * It must be called with wq.lock being held.  This spinlock is
 786  * unlocked while sleeping but @condition testing is done while lock
 787  * is held and when this macro exits the lock is held.
 788  *
 789  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 790  * functions which must match the way they are locked/unlocked outside
 791  * of this macro.
 792  *
 793  * wake_up_locked() has to be called after changing any variable that could
 794  * change the result of the wait condition.
 795  *
 796  * The function will return -ERESTARTSYS if it was interrupted by a
 797  * signal and 0 if @condition evaluated to true.
 798  */
 799 #define wait_event_interruptible_locked(wq, condition)                          \
 800         ((condition)                                                            \
 801          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr))
 802
 803 /**
 804  * wait_event_interruptible_locked_irq - sleep until a condition gets true
 805  * @wq: the waitqueue to wait on
 806  * @condition: a C expression for the event to wait for
 807  *
 808  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 809  * @condition evaluates to true or a signal is received.
 810  * The @condition is checked each time the waitqueue @wq is woken up.
 811  *
 812  * It must be called with wq.lock being held.  This spinlock is
 813  * unlocked while sleeping but @condition testing is done while lock
 814  * is held and when this macro exits the lock is held.
 815  *
 816  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 817  * functions which must match the way they are locked/unlocked outside
 818  * of this macro.
 819  *
 820  * wake_up_locked() has to be called after changing any variable that could
 821  * change the result of the wait condition.
 822  *
 823  * The function will return -ERESTARTSYS if it was interrupted by a
 824  * signal and 0 if @condition evaluated to true.
 825  */
 826 #define wait_event_interruptible_locked_irq(wq, condition)                      \
 827         ((condition)                                                            \
 828          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr_irq))
 829
 830 /**
 831  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
 832  * @wq: the waitqueue to wait on
 833  * @condition: a C expression for the event to wait for
 834  *
 835  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 836  * @condition evaluates to true or a signal is received.
 837  * The @condition is checked each time the waitqueue @wq is woken up.
 838  *
 839  * It must be called with wq.lock being held.  This spinlock is
 840  * unlocked while sleeping but @condition testing is done while lock
 841  * is held and when this macro exits the lock is held.
 842  *
 843  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 844  * functions which must match the way they are locked/unlocked outside
 845  * of this macro.
 846  *
 847  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 848  * set thus when other process waits process on the list if this
 849  * process is awaken further processes are not considered.
 850  *
 851  * wake_up_locked() has to be called after changing any variable that could
 852  * change the result of the wait condition.
 853  *
 854  * The function will return -ERESTARTSYS if it was interrupted by a
 855  * signal and 0 if @condition evaluated to true.
 856  */
 857 #define wait_event_interruptible_exclusive_locked(wq, condition)                \
 858         ((condition)                                                            \
 859          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr))
 860
 861 /**
 862  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
 863  * @wq: the waitqueue to wait on
 864  * @condition: a C expression for the event to wait for
 865  *
 866  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 867  * @condition evaluates to true or a signal is received.
 868  * The @condition is checked each time the waitqueue @wq is woken up.
 869  *
 870  * It must be called with wq.lock being held.  This spinlock is
 871  * unlocked while sleeping but @condition testing is done while lock
 872  * is held and when this macro exits the lock is held.
 873  *
 874  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 875  * functions which must match the way they are locked/unlocked outside
 876  * of this macro.
 877  *
 878  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 879  * set thus when other process waits process on the list if this
 880  * process is awaken further processes are not considered.
 881  *
 882  * wake_up_locked() has to be called after changing any variable that could
 883  * change the result of the wait condition.
 884  *
 885  * The function will return -ERESTARTSYS if it was interrupted by a
 886  * signal and 0 if @condition evaluated to true.
 887  */
 888 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)            \
 889         ((condition)                                                            \
 890          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr_irq))
 891
 892
 893 #define __wait_event_killable(wq, condition)                                    \
 894         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
 895
 896 /**
 897  * wait_event_killable - sleep until a condition gets true
 898  * @wq_head: the waitqueue to wait on
 899  * @condition: a C expression for the event to wait for
 900  *
 901  * The process is put to sleep (TASK_KILLABLE) until the
 902  * @condition evaluates to true or a signal is received.
 903  * The @condition is checked each time the waitqueue @wq_head is woken up.
 904  *
 905  * wake_up() has to be called after changing any variable that could
 906  * change the result of the wait condition.
 907  *
 908  * The function will return -ERESTARTSYS if it was interrupted by a
 909  * signal and 0 if @condition evaluated to true.
 910  */
 911 #define wait_event_killable(wq_head, condition)                                 \
 912 ({                                                                              \
 913         int __ret = 0;                                                          \
 914         might_sleep();                                                          \
 915         if (!(condition))                                                       \
 916                 __ret = __wait_event_killable(wq_head, condition);              \
 917         __ret;                                                                  \
 918 })
 919
 920 #define __wait_event_killable_timeout(wq_head, condition, timeout)              \
 921         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
 922                       TASK_KILLABLE, 0, timeout,                                \
 923                       __ret = schedule_timeout(__ret))
 924
 925 /**
 926  * wait_event_killable_timeout - sleep until a condition gets true or a timeout elapses
 927  * @wq_head: the waitqueue to wait on
 928  * @condition: a C expression for the event to wait for
 929  * @timeout: timeout, in jiffies
 930  *
 931  * The process is put to sleep (TASK_KILLABLE) until the
 932  * @condition evaluates to true or a kill signal is received.
 933  * The @condition is checked each time the waitqueue @wq_head is woken up.
 934  *
 935  * wake_up() has to be called after changing any variable that could
 936  * change the result of the wait condition.
 937  *
 938  * Returns:
 939  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 940  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 941  * the remaining jiffies (at least 1) if the @condition evaluated
 942  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
 943  * interrupted by a kill signal.
 944  *
 945  * Only kill signals interrupt this process.
 946  */
 947 #define wait_event_killable_timeout(wq_head, condition, timeout)                \
 948 ({                                                                              \
 949         long __ret = timeout;                                                   \
 950         might_sleep();                                                          \
 951         if (!___wait_cond_timeout(condition))                                   \
 952                 __ret = __wait_event_killable_timeout(wq_head,                  \
 953                                                 condition, timeout);            \
 954         __ret;                                                                  \
 955 })
 956
 957
 958 #define __wait_event_lock_irq(wq_head, condition, lock, cmd)                    \
 959         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
 960                             spin_unlock_irq(&lock);                             \
 961                             cmd;                                                \
 962                             schedule();                                         \
 963                             spin_lock_irq(&lock))
 964
 965 /**
 966  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
 967  *                           condition is checked under the lock. This
 968  *                           is expected to be called with the lock
 969  *                           taken.
 970  * @wq_head: the waitqueue to wait on
 971  * @condition: a C expression for the event to wait for
 972  * @lock: a locked spinlock_t, which will be released before cmd
 973  *        and schedule() and reacquired afterwards.
 974  * @cmd: a command which is invoked outside the critical section before
 975  *       sleep
 976  *
 977  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 978  * @condition evaluates to true. The @condition is checked each time
 979  * the waitqueue @wq_head is woken up.
 980  *
 981  * wake_up() has to be called after changing any variable that could
 982  * change the result of the wait condition.
 983  *
 984  * This is supposed to be called while holding the lock. The lock is
 985  * dropped before invoking the cmd and going to sleep and is reacquired
 986  * afterwards.
 987  */
 988 #define wait_event_lock_irq_cmd(wq_head, condition, lock, cmd)                  \
 989 do {                                                                            \
 990         if (condition)                                                          \
 991                 break;                                                          \
 992         __wait_event_lock_irq(wq_head, condition, lock, cmd);                   \
 993 } while (0)
 994
 995 /**
 996  * wait_event_lock_irq - sleep until a condition gets true. The
 997  *                       condition is checked under the lock. This
 998  *                       is expected to be called with the lock
 999  *                       taken.
1000  * @wq_head: the waitqueue to wait on
1001  * @condition: a C expression for the event to wait for
1002  * @lock: a locked spinlock_t, which will be released before schedule()
1003  *        and reacquired afterwards.
1004  *
1005  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
1006  * @condition evaluates to true. The @condition is checked each time
1007  * the waitqueue @wq_head is woken up.
1008  *
1009  * wake_up() has to be called after changing any variable that could
1010  * change the result of the wait condition.
1011  *
1012  * This is supposed to be called while holding the lock. The lock is
1013  * dropped before going to sleep and is reacquired afterwards.
1014  */
1015 #define wait_event_lock_irq(wq_head, condition, lock)                           \
1016 do {                                                                            \
1017         if (condition)                                                          \
1018                 break;                                                          \
1019         __wait_event_lock_irq(wq_head, condition, lock, );                      \
1020 } while (0)
1021
1022
1023 #define __wait_event_interruptible_lock_irq(wq_head, condition, lock, cmd)      \
1024         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
1025                       spin_unlock_irq(&lock);                                   \
1026                       cmd;                                                      \
1027                       schedule();                                               \
1028                       spin_lock_irq(&lock))
1029
1030 /**
1031  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
1032  *              The condition is checked under the lock. This is expected to
1033  *              be called with the lock taken.
1034  * @wq_head: the waitqueue to wait on
1035  * @condition: a C expression for the event to wait for
1036  * @lock: a locked spinlock_t, which will be released before cmd and
1037  *        schedule() and reacquired afterwards.
1038  * @cmd: a command which is invoked outside the critical section before
1039  *       sleep
1040  *
1041  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1042  * @condition evaluates to true or a signal is received. The @condition is
1043  * checked each time the waitqueue @wq_head is woken up.
1044  *
1045  * wake_up() has to be called after changing any variable that could
1046  * change the result of the wait condition.
1047  *
1048  * This is supposed to be called while holding the lock. The lock is
1049  * dropped before invoking the cmd and going to sleep and is reacquired
1050  * afterwards.
1051  *
1052  * The macro will return -ERESTARTSYS if it was interrupted by a signal
1053  * and 0 if @condition evaluated to true.
1054  */
1055 #define wait_event_interruptible_lock_irq_cmd(wq_head, condition, lock, cmd)    \
1056 ({                                                                              \
1057         int __ret = 0;                                                          \
1058         if (!(condition))                                                       \
1059                 __ret = __wait_event_interruptible_lock_irq(wq_head,            \
1060                                                 condition, lock, cmd);          \
1061         __ret;                                                                  \
1062 })
1063
1064 /**
1065  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
1066  *              The condition is checked under the lock. This is expected
1067  *              to be called with the lock taken.
1068  * @wq_head: the waitqueue to wait on
1069  * @condition: a C expression for the event to wait for
1070  * @lock: a locked spinlock_t, which will be released before schedule()
1071  *        and reacquired afterwards.
1072  *
1073  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1074  * @condition evaluates to true or signal is received. The @condition is
1075  * checked each time the waitqueue @wq_head is woken up.
1076  *
1077  * wake_up() has to be called after changing any variable that could
1078  * change the result of the wait condition.
1079  *
1080  * This is supposed to be called while holding the lock. The lock is
1081  * dropped before going to sleep and is reacquired afterwards.
1082  *
1083  * The macro will return -ERESTARTSYS if it was interrupted by a signal
1084  * and 0 if @condition evaluated to true.
1085  */
1086 #define wait_event_interruptible_lock_irq(wq_head, condition, lock)             \
1087 ({                                                                              \
1088         int __ret = 0;                                                          \
1089         if (!(condition))                                                       \
1090                 __ret = __wait_event_interruptible_lock_irq(wq_head,            \
1091                                                 condition, lock,);              \
1092         __ret;                                                                  \
1093 })
1094
1095 #define __wait_event_lock_irq_timeout(wq_head, condition, lock, timeout, state) \
1096         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
1097                       state, 0, timeout,                                        \
1098                       spin_unlock_irq(&lock);                                   \
1099                       __ret = schedule_timeout(__ret);                          \
1100                       spin_lock_irq(&lock));
1101
1102 /**
1103  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
1104  *              true or a timeout elapses. The condition is checked under
1105  *              the lock. This is expected to be called with the lock taken.
1106  * @wq_head: the waitqueue to wait on
1107  * @condition: a C expression for the event to wait for
1108  * @lock: a locked spinlock_t, which will be released before schedule()
1109  *        and reacquired afterwards.
1110  * @timeout: timeout, in jiffies
1111  *
1112  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
1113  * @condition evaluates to true or signal is received. The @condition is
1114  * checked each time the waitqueue @wq_head is woken up.
1115  *
1116  * wake_up() has to be called after changing any variable that could
1117  * change the result of the wait condition.
1118  *
1119  * This is supposed to be called while holding the lock. The lock is
1120  * dropped before going to sleep and is reacquired afterwards.
1121  *
1122  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
1123  * was interrupted by a signal, and the remaining jiffies otherwise
1124  * if the condition evaluated to true before the timeout elapsed.
1125  */
1126 #define wait_event_interruptible_lock_irq_timeout(wq_head, condition, lock,     \
1127                                                   timeout)                      \
1128 ({                                                                              \
1129         long __ret = timeout;                                                   \
1130         if (!___wait_cond_timeout(condition))                                   \
1131                 __ret = __wait_event_lock_irq_timeout(                          \
1132                                         wq_head, condition, lock, timeout,      \
1133                                         TASK_INTERRUPTIBLE);                    \
1134         __ret;                                                                  \
1135 })
1136
1137 #define wait_event_lock_irq_timeout(wq_head, condition, lock, timeout)          \
1138 ({                                                                              \
1139         long __ret = timeout;                                                   \
1140         if (!___wait_cond_timeout(condition))                                   \
1141                 __ret = __wait_event_lock_irq_timeout(                          \
1142                                         wq_head, condition, lock, timeout,      \
1143                                         TASK_UNINTERRUPTIBLE);                  \
1144         __ret;                                                                  \
1145 })
1146
1147 /*
1148  * Waitqueues which are removed from the waitqueue_head at wakeup time
1149  */
1150 void prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1151 bool prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1152 long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
1153 void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
1154 long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout);
1155 int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
1156 int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
1157
1158 #define DEFINE_WAIT_FUNC(name, function)                                        \
1159         struct wait_queue_entry name = {                                        \
1160                 .private        = current,                                      \
1161                 .func           = function,                                     \
1162                 .entry          = LIST_HEAD_INIT((name).entry),                 \
1163         }
1164
1165 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
1166
1167 #define init_wait(wait)                                                         \
1168         do {                                                                    \
1169                 (wait)->private = current;                                      \
1170                 (wait)->func = autoremove_wake_function;                        \
1171                 INIT_LIST_HEAD(&(wait)->entry);                                 \
1172                 (wait)->flags = 0;                                              \
1173         } while (0)
1174
1175 #endif /* _LINUX_WAIT_H */