kernel/include/linux/wait.h

   1 #ifndef _LINUX_WAIT_H
   2 #define _LINUX_WAIT_H
   3 /*
   4  * Linux wait queue related types and methods
   5  */
   6 #include <linux/list.h>
   7 #include <linux/stddef.h>
   8 #include <linux/spinlock.h>
   9 #include <asm/current.h>
  10 #include <uapi/linux/wait.h>
  11 #include <linux/atomic.h>
  12
  13 typedef struct __wait_queue wait_queue_t;
  14 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key);
  15 int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, void *key);
  16
  17 /* __wait_queue::flags */
  18 #define WQ_FLAG_EXCLUSIVE       0x01
  19 #define WQ_FLAG_WOKEN           0x02
  20
  21 struct __wait_queue {
  22         unsigned int            flags;
  23         void                    *private;
  24         wait_queue_func_t       func;
  25         struct list_head        task_list;
  26 };
  27
  28 struct wait_bit_key {
  29         void                    *flags;
  30         int                     bit_nr;
  31 #define WAIT_ATOMIC_T_BIT_NR    -1
  32         unsigned long           timeout;
  33 };
  34
  35 struct wait_bit_queue {
  36         struct wait_bit_key     key;
  37         wait_queue_t            wait;
  38 };
  39
  40 struct __wait_queue_head {
  41         spinlock_t              lock;
  42         struct list_head        task_list;
  43 };
  44 typedef struct __wait_queue_head wait_queue_head_t;
  45
  46 struct task_struct;
  47
  48 /*
  49  * Macros for declaration and initialisaton of the datatypes
  50  */
  51
  52 #define __WAITQUEUE_INITIALIZER(name, tsk) {                            \
  53         .private        = tsk,                                          \
  54         .func           = default_wake_function,                        \
  55         .task_list      = { NULL, NULL } }
  56
  57 #define DECLARE_WAITQUEUE(name, tsk)                                    \
  58         wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
  59
  60 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                           \
  61         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),              \
  62         .task_list      = { &(name).task_list, &(name).task_list } }
  63
  64 #define DECLARE_WAIT_QUEUE_HEAD(name) \
  65         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
  66
  67 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)                           \
  68         { .flags = word, .bit_nr = bit, }
  69
  70 #define __WAIT_ATOMIC_T_KEY_INITIALIZER(p)                              \
  71         { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }
  72
  73 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
  74
  75 #define init_waitqueue_head(q)                          \
  76         do {                                            \
  77                 static struct lock_class_key __key;     \
  78                                                         \
  79                 __init_waitqueue_head((q), #q, &__key); \
  80         } while (0)
  81
  82 #ifdef CONFIG_LOCKDEP
  83 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
  84         ({ init_waitqueue_head(&name); name; })
  85 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
  86         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
  87 #else
  88 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
  89 #endif
  90
  91 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
  92 {
  93         q->flags        = 0;
  94         q->private      = p;
  95         q->func         = default_wake_function;
  96 }
  97
  98 static inline void
  99 init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func)
 100 {
 101         q->flags        = 0;
 102         q->private      = NULL;
 103         q->func         = func;
 104 }
 105
 106 static inline int waitqueue_active(wait_queue_head_t *q)
 107 {
 108         return !list_empty(&q->task_list);
 109 }
 110
 111 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 112 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
 113 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 114
 115 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
 116 {
 117         list_add(&new->task_list, &head->task_list);
 118 }
 119
 120 /*
 121  * Used for wake-one threads:
 122  */
 123 static inline void
 124 __add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
 125 {
 126         wait->flags |= WQ_FLAG_EXCLUSIVE;
 127         __add_wait_queue(q, wait);
 128 }
 129
 130 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
 131                                          wait_queue_t *new)
 132 {
 133         list_add_tail(&new->task_list, &head->task_list);
 134 }
 135
 136 static inline void
 137 __add_wait_queue_tail_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
 138 {
 139         wait->flags |= WQ_FLAG_EXCLUSIVE;
 140         __add_wait_queue_tail(q, wait);
 141 }
 142
 143 static inline void
 144 __remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old)
 145 {
 146         list_del(&old->task_list);
 147 }
 148
 149 typedef int wait_bit_action_f(struct wait_bit_key *);
 150 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 151 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
 152 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 153 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
 154 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
 155 void __wake_up_bit(wait_queue_head_t *, void *, int);
 156 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
 157 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
 158 void wake_up_bit(void *, int);
 159 void wake_up_atomic_t(atomic_t *);
 160 int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned);
 161 int out_of_line_wait_on_bit_timeout(void *, int, wait_bit_action_f *, unsigned, unsigned long);
 162 int out_of_line_wait_on_bit_lock(void *, int, wait_bit_action_f *, unsigned);
 163 int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned);
 164 wait_queue_head_t *bit_waitqueue(void *, int);
 165
 166 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
 167 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
 168 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
 169 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL, 1)
 170 #define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)
 171
 172 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 173 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
 174 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
 175 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
 176
 177 /*
 178  * Wakeup macros to be used to report events to the targets.
 179  */
 180 #define wake_up_poll(x, m)                                              \
 181         __wake_up(x, TASK_NORMAL, 1, (void *) (m))
 182 #define wake_up_locked_poll(x, m)                                       \
 183         __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
 184 #define wake_up_interruptible_poll(x, m)                                \
 185         __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
 186 #define wake_up_interruptible_sync_poll(x, m)                           \
 187         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
 188
 189 #define ___wait_cond_timeout(condition)                                 \
 190 ({                                                                      \
 191         bool __cond = (condition);                                      \
 192         if (__cond && !__ret)                                           \
 193                 __ret = 1;                                              \
 194         __cond || !__ret;                                               \
 195 })
 196
 197 #define ___wait_is_interruptible(state)                                 \
 198         (!__builtin_constant_p(state) ||                                \
 199                 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE)  \
 200
 201 /*
 202  * The below macro ___wait_event() has an explicit shadow of the __ret
 203  * variable when used from the wait_event_*() macros.
 204  *
 205  * This is so that both can use the ___wait_cond_timeout() construct
 206  * to wrap the condition.
 207  *
 208  * The type inconsistency of the wait_event_*() __ret variable is also
 209  * on purpose; we use long where we can return timeout values and int
 210  * otherwise.
 211  */
 212
 213 #define ___wait_event(wq, condition, state, exclusive, ret, cmd)        \
 214 ({                                                                      \
 215         __label__ __out;                                                \
 216         wait_queue_t __wait;                                            \
 217         long __ret = ret;       /* explicit shadow */                   \
 218                                                                         \
 219         INIT_LIST_HEAD(&__wait.task_list);                              \
 220         if (exclusive)                                                  \
 221                 __wait.flags = WQ_FLAG_EXCLUSIVE;                       \
 222         else                                                            \
 223                 __wait.flags = 0;                                       \
 224                                                                         \
 225         for (;;) {                                                      \
 226                 long __int = prepare_to_wait_event(&wq, &__wait, state);\
 227                                                                         \
 228                 if (condition)                                          \
 229                         break;                                          \
 230                                                                         \
 231                 if (___wait_is_interruptible(state) && __int) {         \
 232                         __ret = __int;                                  \
 233                         if (exclusive) {                                \
 234                                 abort_exclusive_wait(&wq, &__wait,      \
 235                                                      state, NULL);      \
 236                                 goto __out;                             \
 237                         }                                               \
 238                         break;                                          \
 239                 }                                                       \
 240                                                                         \
 241                 cmd;                                                    \
 242         }                                                               \
 243         finish_wait(&wq, &__wait);                                      \
 244 __out:  __ret;                                                          \
 245 })
 246
 247 #define __wait_event(wq, condition)                                     \
 248         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 249                             schedule())
 250
 251 /**
 252  * wait_event - sleep until a condition gets true
 253  * @wq: the waitqueue to wait on
 254  * @condition: a C expression for the event to wait for
 255  *
 256  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 257  * @condition evaluates to true. The @condition is checked each time
 258  * the waitqueue @wq is woken up.
 259  *
 260  * wake_up() has to be called after changing any variable that could
 261  * change the result of the wait condition.
 262  */
 263 #define wait_event(wq, condition)                                       \
 264 do {                                                                    \
 265         might_sleep();                                                  \
 266         if (condition)                                                  \
 267                 break;                                                  \
 268         __wait_event(wq, condition);                                    \
 269 } while (0)
 270
 271 #define __io_wait_event(wq, condition)                                  \
 272         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 273                             io_schedule())
 274
 275 /*
 276  * io_wait_event() -- like wait_event() but with io_schedule()
 277  */
 278 #define io_wait_event(wq, condition)                                    \
 279 do {                                                                    \
 280         might_sleep();                                                  \
 281         if (condition)                                                  \
 282                 break;                                                  \
 283         __io_wait_event(wq, condition);                                 \
 284 } while (0)
 285
 286 #define __wait_event_freezable(wq, condition)                           \
 287         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
 288                             schedule(); try_to_freeze())
 289
 290 /**
 291  * wait_event - sleep (or freeze) until a condition gets true
 292  * @wq: the waitqueue to wait on
 293  * @condition: a C expression for the event to wait for
 294  *
 295  * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
 296  * to system load) until the @condition evaluates to true. The
 297  * @condition is checked each time the waitqueue @wq is woken up.
 298  *
 299  * wake_up() has to be called after changing any variable that could
 300  * change the result of the wait condition.
 301  */
 302 #define wait_event_freezable(wq, condition)                             \
 303 ({                                                                      \
 304         int __ret = 0;                                                  \
 305         might_sleep();                                                  \
 306         if (!(condition))                                               \
 307                 __ret = __wait_event_freezable(wq, condition);          \
 308         __ret;                                                          \
 309 })
 310
 311 #define __wait_event_timeout(wq, condition, timeout)                    \
 312         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 313                       TASK_UNINTERRUPTIBLE, 0, timeout,                 \
 314                       __ret = schedule_timeout(__ret))
 315
 316 /**
 317  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 318  * @wq: the waitqueue to wait on
 319  * @condition: a C expression for the event to wait for
 320  * @timeout: timeout, in jiffies
 321  *
 322  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 323  * @condition evaluates to true. The @condition is checked each time
 324  * the waitqueue @wq is woken up.
 325  *
 326  * wake_up() has to be called after changing any variable that could
 327  * change the result of the wait condition.
 328  *
 329  * Returns:
 330  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 331  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 332  * or the remaining jiffies (at least 1) if the @condition evaluated
 333  * to %true before the @timeout elapsed.
 334  */
 335 #define wait_event_timeout(wq, condition, timeout)                      \
 336 ({                                                                      \
 337         long __ret = timeout;                                           \
 338         might_sleep();                                                  \
 339         if (!___wait_cond_timeout(condition))                           \
 340                 __ret = __wait_event_timeout(wq, condition, timeout);   \
 341         __ret;                                                          \
 342 })
 343
 344 #define __wait_event_freezable_timeout(wq, condition, timeout)          \
 345         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 346                       TASK_INTERRUPTIBLE, 0, timeout,                   \
 347                       __ret = schedule_timeout(__ret); try_to_freeze())
 348
 349 /*
 350  * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
 351  * increasing load and is freezable.
 352  */
 353 #define wait_event_freezable_timeout(wq, condition, timeout)            \
 354 ({                                                                      \
 355         long __ret = timeout;                                           \
 356         might_sleep();                                                  \
 357         if (!___wait_cond_timeout(condition))                           \
 358                 __ret = __wait_event_freezable_timeout(wq, condition, timeout); \
 359         __ret;                                                          \
 360 })
 361
 362 #define __wait_event_cmd(wq, condition, cmd1, cmd2)                     \
 363         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 364                             cmd1; schedule(); cmd2)
 365
 366 /**
 367  * wait_event_cmd - sleep until a condition gets true
 368  * @wq: the waitqueue to wait on
 369  * @condition: a C expression for the event to wait for
 370  * @cmd1: the command will be executed before sleep
 371  * @cmd2: the command will be executed after sleep
 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 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 #define wait_event_cmd(wq, condition, cmd1, cmd2)                       \
 381 do {                                                                    \
 382         if (condition)                                                  \
 383                 break;                                                  \
 384         __wait_event_cmd(wq, condition, cmd1, cmd2);                    \
 385 } while (0)
 386
 387 #define __wait_event_interruptible(wq, condition)                       \
 388         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
 389                       schedule())
 390
 391 /**
 392  * wait_event_interruptible - sleep until a condition gets true
 393  * @wq: the waitqueue to wait on
 394  * @condition: a C expression for the event to wait for
 395  *
 396  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 397  * @condition evaluates to true or a signal is received.
 398  * The @condition is checked each time the waitqueue @wq is woken up.
 399  *
 400  * wake_up() has to be called after changing any variable that could
 401  * change the result of the wait condition.
 402  *
 403  * The function will return -ERESTARTSYS if it was interrupted by a
 404  * signal and 0 if @condition evaluated to true.
 405  */
 406 #define wait_event_interruptible(wq, condition)                         \
 407 ({                                                                      \
 408         int __ret = 0;                                                  \
 409         might_sleep();                                                  \
 410         if (!(condition))                                               \
 411                 __ret = __wait_event_interruptible(wq, condition);      \
 412         __ret;                                                          \
 413 })
 414
 415 #define __wait_event_interruptible_timeout(wq, condition, timeout)      \
 416         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 417                       TASK_INTERRUPTIBLE, 0, timeout,                   \
 418                       __ret = schedule_timeout(__ret))
 419
 420 /**
 421  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 422  * @wq: the waitqueue to wait on
 423  * @condition: a C expression for the event to wait for
 424  * @timeout: timeout, in jiffies
 425  *
 426  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 427  * @condition evaluates to true or a signal is received.
 428  * The @condition is checked each time the waitqueue @wq is woken up.
 429  *
 430  * wake_up() has to be called after changing any variable that could
 431  * change the result of the wait condition.
 432  *
 433  * Returns:
 434  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 435  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 436  * the remaining jiffies (at least 1) if the @condition evaluated
 437  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
 438  * interrupted by a signal.
 439  */
 440 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
 441 ({                                                                      \
 442         long __ret = timeout;                                           \
 443         might_sleep();                                                  \
 444         if (!___wait_cond_timeout(condition))                           \
 445                 __ret = __wait_event_interruptible_timeout(wq,          \
 446                                                 condition, timeout);    \
 447         __ret;                                                          \
 448 })
 449
 450 #define __wait_event_hrtimeout(wq, condition, timeout, state)           \
 451 ({                                                                      \
 452         int __ret = 0;                                                  \
 453         struct hrtimer_sleeper __t;                                     \
 454                                                                         \
 455         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
 456                               HRTIMER_MODE_REL);                        \
 457         hrtimer_init_sleeper(&__t, current);                            \
 458         if ((timeout).tv64 != KTIME_MAX)                                \
 459                 hrtimer_start_range_ns(&__t.timer, timeout,             \
 460                                        current->timer_slack_ns,         \
 461                                        HRTIMER_MODE_REL);               \
 462                                                                         \
 463         __ret = ___wait_event(wq, condition, state, 0, 0,               \
 464                 if (!__t.task) {                                        \
 465                         __ret = -ETIME;                                 \
 466                         break;                                          \
 467                 }                                                       \
 468                 schedule());                                            \
 469                                                                         \
 470         hrtimer_cancel(&__t.timer);                                     \
 471         destroy_hrtimer_on_stack(&__t.timer);                           \
 472         __ret;                                                          \
 473 })
 474
 475 /**
 476  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
 477  * @wq: the waitqueue to wait on
 478  * @condition: a C expression for the event to wait for
 479  * @timeout: timeout, as a ktime_t
 480  *
 481  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 482  * @condition evaluates to true or a signal is received.
 483  * The @condition is checked each time the waitqueue @wq is woken up.
 484  *
 485  * wake_up() has to be called after changing any variable that could
 486  * change the result of the wait condition.
 487  *
 488  * The function returns 0 if @condition became true, or -ETIME if the timeout
 489  * elapsed.
 490  */
 491 #define wait_event_hrtimeout(wq, condition, timeout)                    \
 492 ({                                                                      \
 493         int __ret = 0;                                                  \
 494         might_sleep();                                                  \
 495         if (!(condition))                                               \
 496                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 497                                                TASK_UNINTERRUPTIBLE);   \
 498         __ret;                                                          \
 499 })
 500
 501 /**
 502  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
 503  * @wq: the waitqueue to wait on
 504  * @condition: a C expression for the event to wait for
 505  * @timeout: timeout, as a ktime_t
 506  *
 507  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 508  * @condition evaluates to true or a signal is received.
 509  * The @condition is checked each time the waitqueue @wq is woken up.
 510  *
 511  * wake_up() has to be called after changing any variable that could
 512  * change the result of the wait condition.
 513  *
 514  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
 515  * interrupted by a signal, or -ETIME if the timeout elapsed.
 516  */
 517 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
 518 ({                                                                      \
 519         long __ret = 0;                                                 \
 520         might_sleep();                                                  \
 521         if (!(condition))                                               \
 522                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 523                                                TASK_INTERRUPTIBLE);     \
 524         __ret;                                                          \
 525 })
 526
 527 #define __wait_event_interruptible_exclusive(wq, condition)             \
 528         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
 529                       schedule())
 530
 531 #define wait_event_interruptible_exclusive(wq, condition)               \
 532 ({                                                                      \
 533         int __ret = 0;                                                  \
 534         might_sleep();                                                  \
 535         if (!(condition))                                               \
 536                 __ret = __wait_event_interruptible_exclusive(wq, condition);\
 537         __ret;                                                          \
 538 })
 539
 540
 541 #define __wait_event_freezable_exclusive(wq, condition)                 \
 542         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
 543                         schedule(); try_to_freeze())
 544
 545 #define wait_event_freezable_exclusive(wq, condition)                   \
 546 ({                                                                      \
 547         int __ret = 0;                                                  \
 548         might_sleep();                                                  \
 549         if (!(condition))                                               \
 550                 __ret = __wait_event_freezable_exclusive(wq, condition);\
 551         __ret;                                                          \
 552 })
 553
 554
 555 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
 556 ({                                                                      \
 557         int __ret = 0;                                                  \
 558         DEFINE_WAIT(__wait);                                            \
 559         if (exclusive)                                                  \
 560                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
 561         do {                                                            \
 562                 if (likely(list_empty(&__wait.task_list)))              \
 563                         __add_wait_queue_tail(&(wq), &__wait);          \
 564                 set_current_state(TASK_INTERRUPTIBLE);                  \
 565                 if (signal_pending(current)) {                          \
 566                         __ret = -ERESTARTSYS;                           \
 567                         break;                                          \
 568                 }                                                       \
 569                 if (irq)                                                \
 570                         spin_unlock_irq(&(wq).lock);                    \
 571                 else                                                    \
 572                         spin_unlock(&(wq).lock);                        \
 573                 schedule();                                             \
 574                 if (irq)                                                \
 575                         spin_lock_irq(&(wq).lock);                      \
 576                 else                                                    \
 577                         spin_lock(&(wq).lock);                          \
 578         } while (!(condition));                                         \
 579         __remove_wait_queue(&(wq), &__wait);                            \
 580         __set_current_state(TASK_RUNNING);                              \
 581         __ret;                                                          \
 582 })
 583
 584
 585 /**
 586  * wait_event_interruptible_locked - sleep until a condition gets true
 587  * @wq: the waitqueue to wait on
 588  * @condition: a C expression for the event to wait for
 589  *
 590  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 591  * @condition evaluates to true or a signal is received.
 592  * The @condition is checked each time the waitqueue @wq is woken up.
 593  *
 594  * It must be called with wq.lock being held.  This spinlock is
 595  * unlocked while sleeping but @condition testing is done while lock
 596  * is held and when this macro exits the lock is held.
 597  *
 598  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 599  * functions which must match the way they are locked/unlocked outside
 600  * of this macro.
 601  *
 602  * wake_up_locked() has to be called after changing any variable that could
 603  * change the result of the wait condition.
 604  *
 605  * The function will return -ERESTARTSYS if it was interrupted by a
 606  * signal and 0 if @condition evaluated to true.
 607  */
 608 #define wait_event_interruptible_locked(wq, condition)                  \
 609         ((condition)                                                    \
 610          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
 611
 612 /**
 613  * wait_event_interruptible_locked_irq - sleep until a condition gets true
 614  * @wq: the waitqueue to wait on
 615  * @condition: a C expression for the event to wait for
 616  *
 617  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 618  * @condition evaluates to true or a signal is received.
 619  * The @condition is checked each time the waitqueue @wq is woken up.
 620  *
 621  * It must be called with wq.lock being held.  This spinlock is
 622  * unlocked while sleeping but @condition testing is done while lock
 623  * is held and when this macro exits the lock is held.
 624  *
 625  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 626  * functions which must match the way they are locked/unlocked outside
 627  * of this macro.
 628  *
 629  * wake_up_locked() has to be called after changing any variable that could
 630  * change the result of the wait condition.
 631  *
 632  * The function will return -ERESTARTSYS if it was interrupted by a
 633  * signal and 0 if @condition evaluated to true.
 634  */
 635 #define wait_event_interruptible_locked_irq(wq, condition)              \
 636         ((condition)                                                    \
 637          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
 638
 639 /**
 640  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
 641  * @wq: the waitqueue to wait on
 642  * @condition: a C expression for the event to wait for
 643  *
 644  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 645  * @condition evaluates to true or a signal is received.
 646  * The @condition is checked each time the waitqueue @wq is woken up.
 647  *
 648  * It must be called with wq.lock being held.  This spinlock is
 649  * unlocked while sleeping but @condition testing is done while lock
 650  * is held and when this macro exits the lock is held.
 651  *
 652  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 653  * functions which must match the way they are locked/unlocked outside
 654  * of this macro.
 655  *
 656  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 657  * set thus when other process waits process on the list if this
 658  * process is awaken further processes are not considered.
 659  *
 660  * wake_up_locked() has to be called after changing any variable that could
 661  * change the result of the wait condition.
 662  *
 663  * The function will return -ERESTARTSYS if it was interrupted by a
 664  * signal and 0 if @condition evaluated to true.
 665  */
 666 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
 667         ((condition)                                                    \
 668          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
 669
 670 /**
 671  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
 672  * @wq: the waitqueue to wait on
 673  * @condition: a C expression for the event to wait for
 674  *
 675  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 676  * @condition evaluates to true or a signal is received.
 677  * The @condition is checked each time the waitqueue @wq is woken up.
 678  *
 679  * It must be called with wq.lock being held.  This spinlock is
 680  * unlocked while sleeping but @condition testing is done while lock
 681  * is held and when this macro exits the lock is held.
 682  *
 683  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 684  * functions which must match the way they are locked/unlocked outside
 685  * of this macro.
 686  *
 687  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 688  * set thus when other process waits process on the list if this
 689  * process is awaken further processes are not considered.
 690  *
 691  * wake_up_locked() has to be called after changing any variable that could
 692  * change the result of the wait condition.
 693  *
 694  * The function will return -ERESTARTSYS if it was interrupted by a
 695  * signal and 0 if @condition evaluated to true.
 696  */
 697 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
 698         ((condition)                                                    \
 699          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
 700
 701
 702 #define __wait_event_killable(wq, condition)                            \
 703         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
 704
 705 /**
 706  * wait_event_killable - sleep until a condition gets true
 707  * @wq: the waitqueue to wait on
 708  * @condition: a C expression for the event to wait for
 709  *
 710  * The process is put to sleep (TASK_KILLABLE) until the
 711  * @condition evaluates to true or a signal is received.
 712  * The @condition is checked each time the waitqueue @wq is woken up.
 713  *
 714  * wake_up() has to be called after changing any variable that could
 715  * change the result of the wait condition.
 716  *
 717  * The function will return -ERESTARTSYS if it was interrupted by a
 718  * signal and 0 if @condition evaluated to true.
 719  */
 720 #define wait_event_killable(wq, condition)                              \
 721 ({                                                                      \
 722         int __ret = 0;                                                  \
 723         might_sleep();                                                  \
 724         if (!(condition))                                               \
 725                 __ret = __wait_event_killable(wq, condition);           \
 726         __ret;                                                          \
 727 })
 728
 729
 730 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 731         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 732                             spin_unlock_irq(&lock);                     \
 733                             cmd;                                        \
 734                             schedule();                                 \
 735                             spin_lock_irq(&lock))
 736
 737 /**
 738  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
 739  *                           condition is checked under the lock. This
 740  *                           is expected to be called with the lock
 741  *                           taken.
 742  * @wq: the waitqueue to wait on
 743  * @condition: a C expression for the event to wait for
 744  * @lock: a locked spinlock_t, which will be released before cmd
 745  *        and schedule() and reacquired afterwards.
 746  * @cmd: a command which is invoked outside the critical section before
 747  *       sleep
 748  *
 749  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 750  * @condition evaluates to true. The @condition is checked each time
 751  * the waitqueue @wq is woken up.
 752  *
 753  * wake_up() has to be called after changing any variable that could
 754  * change the result of the wait condition.
 755  *
 756  * This is supposed to be called while holding the lock. The lock is
 757  * dropped before invoking the cmd and going to sleep and is reacquired
 758  * afterwards.
 759  */
 760 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
 761 do {                                                                    \
 762         if (condition)                                                  \
 763                 break;                                                  \
 764         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 765 } while (0)
 766
 767 /**
 768  * wait_event_lock_irq - sleep until a condition gets true. The
 769  *                       condition is checked under the lock. This
 770  *                       is expected to be called with the lock
 771  *                       taken.
 772  * @wq: the waitqueue to wait on
 773  * @condition: a C expression for the event to wait for
 774  * @lock: a locked spinlock_t, which will be released before schedule()
 775  *        and reacquired afterwards.
 776  *
 777  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 778  * @condition evaluates to true. The @condition is checked each time
 779  * the waitqueue @wq is woken up.
 780  *
 781  * wake_up() has to be called after changing any variable that could
 782  * change the result of the wait condition.
 783  *
 784  * This is supposed to be called while holding the lock. The lock is
 785  * dropped before going to sleep and is reacquired afterwards.
 786  */
 787 #define wait_event_lock_irq(wq, condition, lock)                        \
 788 do {                                                                    \
 789         if (condition)                                                  \
 790                 break;                                                  \
 791         __wait_event_lock_irq(wq, condition, lock, );                   \
 792 } while (0)
 793
 794
 795 #define __wait_event_interruptible_lock_irq(wq, condition, lock, cmd)   \
 796         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
 797                       spin_unlock_irq(&lock);                           \
 798                       cmd;                                              \
 799                       schedule();                                       \
 800                       spin_lock_irq(&lock))
 801
 802 /**
 803  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
 804  *              The condition is checked under the lock. This is expected to
 805  *              be called with the lock taken.
 806  * @wq: the waitqueue to wait on
 807  * @condition: a C expression for the event to wait for
 808  * @lock: a locked spinlock_t, which will be released before cmd and
 809  *        schedule() and reacquired afterwards.
 810  * @cmd: a command which is invoked outside the critical section before
 811  *       sleep
 812  *
 813  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 814  * @condition evaluates to true or a signal is received. The @condition is
 815  * checked each time the waitqueue @wq is woken up.
 816  *
 817  * wake_up() has to be called after changing any variable that could
 818  * change the result of the wait condition.
 819  *
 820  * This is supposed to be called while holding the lock. The lock is
 821  * dropped before invoking the cmd and going to sleep and is reacquired
 822  * afterwards.
 823  *
 824  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 825  * and 0 if @condition evaluated to true.
 826  */
 827 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
 828 ({                                                                      \
 829         int __ret = 0;                                                  \
 830         if (!(condition))                                               \
 831                 __ret = __wait_event_interruptible_lock_irq(wq,         \
 832                                                 condition, lock, cmd);  \
 833         __ret;                                                          \
 834 })
 835
 836 /**
 837  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
 838  *              The condition is checked under the lock. This is expected
 839  *              to be called with the lock taken.
 840  * @wq: the waitqueue to wait on
 841  * @condition: a C expression for the event to wait for
 842  * @lock: a locked spinlock_t, which will be released before schedule()
 843  *        and reacquired afterwards.
 844  *
 845  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 846  * @condition evaluates to true or signal is received. The @condition is
 847  * checked each time the waitqueue @wq is woken up.
 848  *
 849  * wake_up() has to be called after changing any variable that could
 850  * change the result of the wait condition.
 851  *
 852  * This is supposed to be called while holding the lock. The lock is
 853  * dropped before going to sleep and is reacquired afterwards.
 854  *
 855  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 856  * and 0 if @condition evaluated to true.
 857  */
 858 #define wait_event_interruptible_lock_irq(wq, condition, lock)          \
 859 ({                                                                      \
 860         int __ret = 0;                                                  \
 861         if (!(condition))                                               \
 862                 __ret = __wait_event_interruptible_lock_irq(wq,         \
 863                                                 condition, lock,);      \
 864         __ret;                                                          \
 865 })
 866
 867 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
 868                                                     lock, timeout)      \
 869         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 870                       TASK_INTERRUPTIBLE, 0, timeout,                   \
 871                       spin_unlock_irq(&lock);                           \
 872                       __ret = schedule_timeout(__ret);                  \
 873                       spin_lock_irq(&lock));
 874
 875 /**
 876  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
 877  *              true or a timeout elapses. The condition is checked under
 878  *              the lock. This is expected to be called with the lock taken.
 879  * @wq: the waitqueue to wait on
 880  * @condition: a C expression for the event to wait for
 881  * @lock: a locked spinlock_t, which will be released before schedule()
 882  *        and reacquired afterwards.
 883  * @timeout: timeout, in jiffies
 884  *
 885  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 886  * @condition evaluates to true or signal is received. The @condition is
 887  * checked each time the waitqueue @wq is woken up.
 888  *
 889  * wake_up() has to be called after changing any variable that could
 890  * change the result of the wait condition.
 891  *
 892  * This is supposed to be called while holding the lock. The lock is
 893  * dropped before going to sleep and is reacquired afterwards.
 894  *
 895  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
 896  * was interrupted by a signal, and the remaining jiffies otherwise
 897  * if the condition evaluated to true before the timeout elapsed.
 898  */
 899 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
 900                                                   timeout)              \
 901 ({                                                                      \
 902         long __ret = timeout;                                           \
 903         if (!___wait_cond_timeout(condition))                           \
 904                 __ret = __wait_event_interruptible_lock_irq_timeout(    \
 905                                         wq, condition, lock, timeout);  \
 906         __ret;                                                          \
 907 })
 908
 909 /*
 910  * Waitqueues which are removed from the waitqueue_head at wakeup time
 911  */
 912 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
 913 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
 914 long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state);
 915 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
 916 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key);
 917 long wait_woken(wait_queue_t *wait, unsigned mode, long timeout);
 918 int woken_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 919 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 920 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 921
 922 #define DEFINE_WAIT_FUNC(name, function)                                \
 923         wait_queue_t name = {                                           \
 924                 .private        = current,                              \
 925                 .func           = function,                             \
 926                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
 927         }
 928
 929 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
 930
 931 #define DEFINE_WAIT_BIT(name, word, bit)                                \
 932         struct wait_bit_queue name = {                                  \
 933                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
 934                 .wait   = {                                             \
 935                         .private        = current,                      \
 936                         .func           = wake_bit_function,            \
 937                         .task_list      =                               \
 938                                 LIST_HEAD_INIT((name).wait.task_list),  \
 939                 },                                                      \
 940         }
 941
 942 #define init_wait(wait)                                                 \
 943         do {                                                            \
 944                 (wait)->private = current;                              \
 945                 (wait)->func = autoremove_wake_function;                \
 946                 INIT_LIST_HEAD(&(wait)->task_list);                     \
 947                 (wait)->flags = 0;                                      \
 948         } while (0)
 949
 950
 951 extern int bit_wait(struct wait_bit_key *);
 952 extern int bit_wait_io(struct wait_bit_key *);
 953 extern int bit_wait_timeout(struct wait_bit_key *);
 954 extern int bit_wait_io_timeout(struct wait_bit_key *);
 955
 956 /**
 957  * wait_on_bit - wait for a bit to be cleared
 958  * @word: the word being waited on, a kernel virtual address
 959  * @bit: the bit of the word being waited on
 960  * @mode: the task state to sleep in
 961  *
 962  * There is a standard hashed waitqueue table for generic use. This
 963  * is the part of the hashtable's accessor API that waits on a bit.
 964  * For instance, if one were to have waiters on a bitflag, one would
 965  * call wait_on_bit() in threads waiting for the bit to clear.
 966  * One uses wait_on_bit() where one is waiting for the bit to clear,
 967  * but has no intention of setting it.
 968  * Returned value will be zero if the bit was cleared, or non-zero
 969  * if the process received a signal and the mode permitted wakeup
 970  * on that signal.
 971  */
 972 static inline int
 973 wait_on_bit(void *word, int bit, unsigned mode)
 974 {
 975         might_sleep();
 976         if (!test_bit(bit, word))
 977                 return 0;
 978         return out_of_line_wait_on_bit(word, bit,
 979                                        bit_wait,
 980                                        mode);
 981 }
 982
 983 /**
 984  * wait_on_bit_io - wait for a bit to be cleared
 985  * @word: the word being waited on, a kernel virtual address
 986  * @bit: the bit of the word being waited on
 987  * @mode: the task state to sleep in
 988  *
 989  * Use the standard hashed waitqueue table to wait for a bit
 990  * to be cleared.  This is similar to wait_on_bit(), but calls
 991  * io_schedule() instead of schedule() for the actual waiting.
 992  *
 993  * Returned value will be zero if the bit was cleared, or non-zero
 994  * if the process received a signal and the mode permitted wakeup
 995  * on that signal.
 996  */
 997 static inline int
 998 wait_on_bit_io(void *word, int bit, unsigned mode)
 999 {
1000         might_sleep();
1001         if (!test_bit(bit, word))
1002                 return 0;
1003         return out_of_line_wait_on_bit(word, bit,
1004                                        bit_wait_io,
1005                                        mode);
1006 }
1007
1008 /**
1009  * wait_on_bit_timeout - wait for a bit to be cleared or a timeout elapses
1010  * @word: the word being waited on, a kernel virtual address
1011  * @bit: the bit of the word being waited on
1012  * @mode: the task state to sleep in
1013  * @timeout: timeout, in jiffies
1014  *
1015  * Use the standard hashed waitqueue table to wait for a bit
1016  * to be cleared. This is similar to wait_on_bit(), except also takes a
1017  * timeout parameter.
1018  *
1019  * Returned value will be zero if the bit was cleared before the
1020  * @timeout elapsed, or non-zero if the @timeout elapsed or process
1021  * received a signal and the mode permitted wakeup on that signal.
1022  */
1023 static inline int
1024 wait_on_bit_timeout(void *word, int bit, unsigned mode, unsigned long timeout)
1025 {
1026         might_sleep();
1027         if (!test_bit(bit, word))
1028                 return 0;
1029         return out_of_line_wait_on_bit_timeout(word, bit,
1030                                                bit_wait_timeout,
1031                                                mode, timeout);
1032 }
1033
1034 /**
1035  * wait_on_bit_action - wait for a bit to be cleared
1036  * @word: the word being waited on, a kernel virtual address
1037  * @bit: the bit of the word being waited on
1038  * @action: the function used to sleep, which may take special actions
1039  * @mode: the task state to sleep in
1040  *
1041  * Use the standard hashed waitqueue table to wait for a bit
1042  * to be cleared, and allow the waiting action to be specified.
1043  * This is like wait_on_bit() but allows fine control of how the waiting
1044  * is done.
1045  *
1046  * Returned value will be zero if the bit was cleared, or non-zero
1047  * if the process received a signal and the mode permitted wakeup
1048  * on that signal.
1049  */
1050 static inline int
1051 wait_on_bit_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
1052 {
1053         might_sleep();
1054         if (!test_bit(bit, word))
1055                 return 0;
1056         return out_of_line_wait_on_bit(word, bit, action, mode);
1057 }
1058
1059 /**
1060  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
1061  * @word: the word being waited on, a kernel virtual address
1062  * @bit: the bit of the word being waited on
1063  * @mode: the task state to sleep in
1064  *
1065  * There is a standard hashed waitqueue table for generic use. This
1066  * is the part of the hashtable's accessor API that waits on a bit
1067  * when one intends to set it, for instance, trying to lock bitflags.
1068  * For instance, if one were to have waiters trying to set bitflag
1069  * and waiting for it to clear before setting it, one would call
1070  * wait_on_bit() in threads waiting to be able to set the bit.
1071  * One uses wait_on_bit_lock() where one is waiting for the bit to
1072  * clear with the intention of setting it, and when done, clearing it.
1073  *
1074  * Returns zero if the bit was (eventually) found to be clear and was
1075  * set.  Returns non-zero if a signal was delivered to the process and
1076  * the @mode allows that signal to wake the process.
1077  */
1078 static inline int
1079 wait_on_bit_lock(void *word, int bit, unsigned mode)
1080 {
1081         might_sleep();
1082         if (!test_and_set_bit(bit, word))
1083                 return 0;
1084         return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode);
1085 }
1086
1087 /**
1088  * wait_on_bit_lock_io - wait for a bit to be cleared, when wanting to set it
1089  * @word: the word being waited on, a kernel virtual address
1090  * @bit: the bit of the word being waited on
1091  * @mode: the task state to sleep in
1092  *
1093  * Use the standard hashed waitqueue table to wait for a bit
1094  * to be cleared and then to atomically set it.  This is similar
1095  * to wait_on_bit(), but calls io_schedule() instead of schedule()
1096  * for the actual waiting.
1097  *
1098  * Returns zero if the bit was (eventually) found to be clear and was
1099  * set.  Returns non-zero if a signal was delivered to the process and
1100  * the @mode allows that signal to wake the process.
1101  */
1102 static inline int
1103 wait_on_bit_lock_io(void *word, int bit, unsigned mode)
1104 {
1105         might_sleep();
1106         if (!test_and_set_bit(bit, word))
1107                 return 0;
1108         return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode);
1109 }
1110
1111 /**
1112  * wait_on_bit_lock_action - wait for a bit to be cleared, when wanting to set it
1113  * @word: the word being waited on, a kernel virtual address
1114  * @bit: the bit of the word being waited on
1115  * @action: the function used to sleep, which may take special actions
1116  * @mode: the task state to sleep in
1117  *
1118  * Use the standard hashed waitqueue table to wait for a bit
1119  * to be cleared and then to set it, and allow the waiting action
1120  * to be specified.
1121  * This is like wait_on_bit() but allows fine control of how the waiting
1122  * is done.
1123  *
1124  * Returns zero if the bit was (eventually) found to be clear and was
1125  * set.  Returns non-zero if a signal was delivered to the process and
1126  * the @mode allows that signal to wake the process.
1127  */
1128 static inline int
1129 wait_on_bit_lock_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
1130 {
1131         might_sleep();
1132         if (!test_and_set_bit(bit, word))
1133                 return 0;
1134         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
1135 }
1136
1137 /**
1138  * wait_on_atomic_t - Wait for an atomic_t to become 0
1139  * @val: The atomic value being waited on, a kernel virtual address
1140  * @action: the function used to sleep, which may take special actions
1141  * @mode: the task state to sleep in
1142  *
1143  * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
1144  * the purpose of getting a waitqueue, but we set the key to a bit number
1145  * outside of the target 'word'.
1146  */
1147 static inline
1148 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
1149 {
1150         might_sleep();
1151         if (atomic_read(val) == 0)
1152                 return 0;
1153         return out_of_line_wait_on_atomic_t(val, action, mode);
1154 }
1155
1156 #endif /* _LINUX_WAIT_H */