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
  12 typedef struct __wait_queue wait_queue_t;
  13 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key);
  14 int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, void *key);
  15
  16 struct __wait_queue {
  17         unsigned int            flags;
  18 #define WQ_FLAG_EXCLUSIVE       0x01
  19         void                    *private;
  20         wait_queue_func_t       func;
  21         struct list_head        task_list;
  22 };
  23
  24 struct wait_bit_key {
  25         void                    *flags;
  26         int                     bit_nr;
  27 #define WAIT_ATOMIC_T_BIT_NR    -1
  28         unsigned long           timeout;
  29 };
  30
  31 struct wait_bit_queue {
  32         struct wait_bit_key     key;
  33         wait_queue_t            wait;
  34 };
  35
  36 struct __wait_queue_head {
  37         spinlock_t              lock;
  38         struct list_head        task_list;
  39 };
  40 typedef struct __wait_queue_head wait_queue_head_t;
  41
  42 struct task_struct;
  43
  44 /*
  45  * Macros for declaration and initialisaton of the datatypes
  46  */
  47
  48 #define __WAITQUEUE_INITIALIZER(name, tsk) {                            \
  49         .private        = tsk,                                          \
  50         .func           = default_wake_function,                        \
  51         .task_list      = { NULL, NULL } }
  52
  53 #define DECLARE_WAITQUEUE(name, tsk)                                    \
  54         wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
  55
  56 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                           \
  57         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),              \
  58         .task_list      = { &(name).task_list, &(name).task_list } }
  59
  60 #define DECLARE_WAIT_QUEUE_HEAD(name) \
  61         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
  62
  63 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)                           \
  64         { .flags = word, .bit_nr = bit, }
  65
  66 #define __WAIT_ATOMIC_T_KEY_INITIALIZER(p)                              \
  67         { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }
  68
  69 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
  70
  71 #define init_waitqueue_head(q)                          \
  72         do {                                            \
  73                 static struct lock_class_key __key;     \
  74                                                         \
  75                 __init_waitqueue_head((q), #q, &__key); \
  76         } while (0)
  77
  78 #ifdef CONFIG_LOCKDEP
  79 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
  80         ({ init_waitqueue_head(&name); name; })
  81 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
  82         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
  83 #else
  84 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
  85 #endif
  86
  87 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
  88 {
  89         q->flags        = 0;
  90         q->private      = p;
  91         q->func         = default_wake_function;
  92 }
  93
  94 static inline void
  95 init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func)
  96 {
  97         q->flags        = 0;
  98         q->private      = NULL;
  99         q->func         = func;
 100 }
 101
 102 static inline int waitqueue_active(wait_queue_head_t *q)
 103 {
 104         return !list_empty(&q->task_list);
 105 }
 106
 107 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 108 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
 109 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 110
 111 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
 112 {
 113         list_add(&new->task_list, &head->task_list);
 114 }
 115
 116 /*
 117  * Used for wake-one threads:
 118  */
 119 static inline void
 120 __add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
 121 {
 122         wait->flags |= WQ_FLAG_EXCLUSIVE;
 123         __add_wait_queue(q, wait);
 124 }
 125
 126 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
 127                                          wait_queue_t *new)
 128 {
 129         list_add_tail(&new->task_list, &head->task_list);
 130 }
 131
 132 static inline void
 133 __add_wait_queue_tail_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
 134 {
 135         wait->flags |= WQ_FLAG_EXCLUSIVE;
 136         __add_wait_queue_tail(q, wait);
 137 }
 138
 139 static inline void
 140 __remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old)
 141 {
 142         list_del(&old->task_list);
 143 }
 144
 145 typedef int wait_bit_action_f(struct wait_bit_key *);
 146 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 147 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
 148 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 149 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
 150 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
 151 void __wake_up_bit(wait_queue_head_t *, void *, int);
 152 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
 153 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
 154 void wake_up_bit(void *, int);
 155 void wake_up_atomic_t(atomic_t *);
 156 int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned);
 157 int out_of_line_wait_on_bit_timeout(void *, int, wait_bit_action_f *, unsigned, unsigned long);
 158 int out_of_line_wait_on_bit_lock(void *, int, wait_bit_action_f *, unsigned);
 159 int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned);
 160 wait_queue_head_t *bit_waitqueue(void *, int);
 161
 162 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
 163 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
 164 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
 165 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL, 1)
 166 #define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)
 167
 168 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 169 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
 170 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
 171 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
 172
 173 /*
 174  * Wakeup macros to be used to report events to the targets.
 175  */
 176 #define wake_up_poll(x, m)                                              \
 177         __wake_up(x, TASK_NORMAL, 1, (void *) (m))
 178 #define wake_up_locked_poll(x, m)                                       \
 179         __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
 180 #define wake_up_interruptible_poll(x, m)                                \
 181         __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
 182 #define wake_up_interruptible_sync_poll(x, m)                           \
 183         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
 184
 185 #define ___wait_cond_timeout(condition)                                 \
 186 ({                                                                      \
 187         bool __cond = (condition);                                      \
 188         if (__cond && !__ret)                                           \
 189                 __ret = 1;                                              \
 190         __cond || !__ret;                                               \
 191 })
 192
 193 #define ___wait_is_interruptible(state)                                 \
 194         (!__builtin_constant_p(state) ||                                \
 195                 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE)  \
 196
 197 /*
 198  * The below macro ___wait_event() has an explicit shadow of the __ret
 199  * variable when used from the wait_event_*() macros.
 200  *
 201  * This is so that both can use the ___wait_cond_timeout() construct
 202  * to wrap the condition.
 203  *
 204  * The type inconsistency of the wait_event_*() __ret variable is also
 205  * on purpose; we use long where we can return timeout values and int
 206  * otherwise.
 207  */
 208
 209 #define ___wait_event(wq, condition, state, exclusive, ret, cmd)        \
 210 ({                                                                      \
 211         __label__ __out;                                                \
 212         wait_queue_t __wait;                                            \
 213         long __ret = ret;       /* explicit shadow */                   \
 214                                                                         \
 215         INIT_LIST_HEAD(&__wait.task_list);                              \
 216         if (exclusive)                                                  \
 217                 __wait.flags = WQ_FLAG_EXCLUSIVE;                       \
 218         else                                                            \
 219                 __wait.flags = 0;                                       \
 220                                                                         \
 221         for (;;) {                                                      \
 222                 long __int = prepare_to_wait_event(&wq, &__wait, state);\
 223                                                                         \
 224                 if (condition)                                          \
 225                         break;                                          \
 226                                                                         \
 227                 if (___wait_is_interruptible(state) && __int) {         \
 228                         __ret = __int;                                  \
 229                         if (exclusive) {                                \
 230                                 abort_exclusive_wait(&wq, &__wait,      \
 231                                                      state, NULL);      \
 232                                 goto __out;                             \
 233                         }                                               \
 234                         break;                                          \
 235                 }                                                       \
 236                                                                         \
 237                 cmd;                                                    \
 238         }                                                               \
 239         finish_wait(&wq, &__wait);                                      \
 240 __out:  __ret;                                                          \
 241 })
 242
 243 #define __wait_event(wq, condition)                                     \
 244         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 245                             schedule())
 246
 247 /**
 248  * wait_event - sleep until a condition gets true
 249  * @wq: the waitqueue to wait on
 250  * @condition: a C expression for the event to wait for
 251  *
 252  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 253  * @condition evaluates to true. The @condition is checked each time
 254  * the waitqueue @wq is woken up.
 255  *
 256  * wake_up() has to be called after changing any variable that could
 257  * change the result of the wait condition.
 258  */
 259 #define wait_event(wq, condition)                                       \
 260 do {                                                                    \
 261         if (condition)                                                  \
 262                 break;                                                  \
 263         __wait_event(wq, condition);                                    \
 264 } while (0)
 265
 266 #define __wait_event_timeout(wq, condition, timeout)                    \
 267         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 268                       TASK_UNINTERRUPTIBLE, 0, timeout,                 \
 269                       __ret = schedule_timeout(__ret))
 270
 271 /**
 272  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 273  * @wq: the waitqueue to wait on
 274  * @condition: a C expression for the event to wait for
 275  * @timeout: timeout, in jiffies
 276  *
 277  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 278  * @condition evaluates to true. The @condition is checked each time
 279  * the waitqueue @wq is woken up.
 280  *
 281  * wake_up() has to be called after changing any variable that could
 282  * change the result of the wait condition.
 283  *
 284  * The function returns 0 if the @timeout elapsed, or the remaining
 285  * jiffies (at least 1) if the @condition evaluated to %true before
 286  * the @timeout elapsed.
 287  */
 288 #define wait_event_timeout(wq, condition, timeout)                      \
 289 ({                                                                      \
 290         long __ret = timeout;                                           \
 291         if (!___wait_cond_timeout(condition))                           \
 292                 __ret = __wait_event_timeout(wq, condition, timeout);   \
 293         __ret;                                                          \
 294 })
 295
 296 #define __wait_event_cmd(wq, condition, cmd1, cmd2)                     \
 297         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 298                             cmd1; schedule(); cmd2)
 299
 300 /**
 301  * wait_event_cmd - sleep until a condition gets true
 302  * @wq: the waitqueue to wait on
 303  * @condition: a C expression for the event to wait for
 304  * @cmd1: the command will be executed before sleep
 305  * @cmd2: the command will be executed after sleep
 306  *
 307  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 308  * @condition evaluates to true. The @condition is checked each time
 309  * the waitqueue @wq is woken up.
 310  *
 311  * wake_up() has to be called after changing any variable that could
 312  * change the result of the wait condition.
 313  */
 314 #define wait_event_cmd(wq, condition, cmd1, cmd2)                       \
 315 do {                                                                    \
 316         if (condition)                                                  \
 317                 break;                                                  \
 318         __wait_event_cmd(wq, condition, cmd1, cmd2);                    \
 319 } while (0)
 320
 321 #define __wait_event_interruptible(wq, condition)                       \
 322         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
 323                       schedule())
 324
 325 /**
 326  * wait_event_interruptible - sleep until a condition gets true
 327  * @wq: the waitqueue to wait on
 328  * @condition: a C expression for the event to wait for
 329  *
 330  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 331  * @condition evaluates to true or a signal is received.
 332  * The @condition is checked each time the waitqueue @wq is woken up.
 333  *
 334  * wake_up() has to be called after changing any variable that could
 335  * change the result of the wait condition.
 336  *
 337  * The function will return -ERESTARTSYS if it was interrupted by a
 338  * signal and 0 if @condition evaluated to true.
 339  */
 340 #define wait_event_interruptible(wq, condition)                         \
 341 ({                                                                      \
 342         int __ret = 0;                                                  \
 343         if (!(condition))                                               \
 344                 __ret = __wait_event_interruptible(wq, condition);      \
 345         __ret;                                                          \
 346 })
 347
 348 #define __wait_event_interruptible_timeout(wq, condition, timeout)      \
 349         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 350                       TASK_INTERRUPTIBLE, 0, timeout,                   \
 351                       __ret = schedule_timeout(__ret))
 352
 353 /**
 354  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 355  * @wq: the waitqueue to wait on
 356  * @condition: a C expression for the event to wait for
 357  * @timeout: timeout, in jiffies
 358  *
 359  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 360  * @condition evaluates to true or a signal is received.
 361  * The @condition is checked each time the waitqueue @wq is woken up.
 362  *
 363  * wake_up() has to be called after changing any variable that could
 364  * change the result of the wait condition.
 365  *
 366  * Returns:
 367  * 0 if the @timeout elapsed, -%ERESTARTSYS if it was interrupted by
 368  * a signal, or the remaining jiffies (at least 1) if the @condition
 369  * evaluated to %true before the @timeout elapsed.
 370  */
 371 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
 372 ({                                                                      \
 373         long __ret = timeout;                                           \
 374         if (!___wait_cond_timeout(condition))                           \
 375                 __ret = __wait_event_interruptible_timeout(wq,          \
 376                                                 condition, timeout);    \
 377         __ret;                                                          \
 378 })
 379
 380 #define __wait_event_hrtimeout(wq, condition, timeout, state)           \
 381 ({                                                                      \
 382         int __ret = 0;                                                  \
 383         struct hrtimer_sleeper __t;                                     \
 384                                                                         \
 385         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
 386                               HRTIMER_MODE_REL);                        \
 387         hrtimer_init_sleeper(&__t, current);                            \
 388         if ((timeout).tv64 != KTIME_MAX)                                \
 389                 hrtimer_start_range_ns(&__t.timer, timeout,             \
 390                                        current->timer_slack_ns,         \
 391                                        HRTIMER_MODE_REL);               \
 392                                                                         \
 393         __ret = ___wait_event(wq, condition, state, 0, 0,               \
 394                 if (!__t.task) {                                        \
 395                         __ret = -ETIME;                                 \
 396                         break;                                          \
 397                 }                                                       \
 398                 schedule());                                            \
 399                                                                         \
 400         hrtimer_cancel(&__t.timer);                                     \
 401         destroy_hrtimer_on_stack(&__t.timer);                           \
 402         __ret;                                                          \
 403 })
 404
 405 /**
 406  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
 407  * @wq: the waitqueue to wait on
 408  * @condition: a C expression for the event to wait for
 409  * @timeout: timeout, as a ktime_t
 410  *
 411  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 412  * @condition evaluates to true or a signal is received.
 413  * The @condition is checked each time the waitqueue @wq is woken up.
 414  *
 415  * wake_up() has to be called after changing any variable that could
 416  * change the result of the wait condition.
 417  *
 418  * The function returns 0 if @condition became true, or -ETIME if the timeout
 419  * elapsed.
 420  */
 421 #define wait_event_hrtimeout(wq, condition, timeout)                    \
 422 ({                                                                      \
 423         int __ret = 0;                                                  \
 424         if (!(condition))                                               \
 425                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 426                                                TASK_UNINTERRUPTIBLE);   \
 427         __ret;                                                          \
 428 })
 429
 430 /**
 431  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
 432  * @wq: the waitqueue to wait on
 433  * @condition: a C expression for the event to wait for
 434  * @timeout: timeout, as a ktime_t
 435  *
 436  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 437  * @condition evaluates to true or a signal is received.
 438  * The @condition is checked each time the waitqueue @wq is woken up.
 439  *
 440  * wake_up() has to be called after changing any variable that could
 441  * change the result of the wait condition.
 442  *
 443  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
 444  * interrupted by a signal, or -ETIME if the timeout elapsed.
 445  */
 446 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
 447 ({                                                                      \
 448         long __ret = 0;                                                 \
 449         if (!(condition))                                               \
 450                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 451                                                TASK_INTERRUPTIBLE);     \
 452         __ret;                                                          \
 453 })
 454
 455 #define __wait_event_interruptible_exclusive(wq, condition)             \
 456         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
 457                       schedule())
 458
 459 #define wait_event_interruptible_exclusive(wq, condition)               \
 460 ({                                                                      \
 461         int __ret = 0;                                                  \
 462         if (!(condition))                                               \
 463                 __ret = __wait_event_interruptible_exclusive(wq, condition);\
 464         __ret;                                                          \
 465 })
 466
 467
 468 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
 469 ({                                                                      \
 470         int __ret = 0;                                                  \
 471         DEFINE_WAIT(__wait);                                            \
 472         if (exclusive)                                                  \
 473                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
 474         do {                                                            \
 475                 if (likely(list_empty(&__wait.task_list)))              \
 476                         __add_wait_queue_tail(&(wq), &__wait);          \
 477                 set_current_state(TASK_INTERRUPTIBLE);                  \
 478                 if (signal_pending(current)) {                          \
 479                         __ret = -ERESTARTSYS;                           \
 480                         break;                                          \
 481                 }                                                       \
 482                 if (irq)                                                \
 483                         spin_unlock_irq(&(wq).lock);                    \
 484                 else                                                    \
 485                         spin_unlock(&(wq).lock);                        \
 486                 schedule();                                             \
 487                 if (irq)                                                \
 488                         spin_lock_irq(&(wq).lock);                      \
 489                 else                                                    \
 490                         spin_lock(&(wq).lock);                          \
 491         } while (!(condition));                                         \
 492         __remove_wait_queue(&(wq), &__wait);                            \
 493         __set_current_state(TASK_RUNNING);                              \
 494         __ret;                                                          \
 495 })
 496
 497
 498 /**
 499  * wait_event_interruptible_locked - sleep until a condition gets true
 500  * @wq: the waitqueue to wait on
 501  * @condition: a C expression for the event to wait for
 502  *
 503  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 504  * @condition evaluates to true or a signal is received.
 505  * The @condition is checked each time the waitqueue @wq is woken up.
 506  *
 507  * It must be called with wq.lock being held.  This spinlock is
 508  * unlocked while sleeping but @condition testing is done while lock
 509  * is held and when this macro exits the lock is held.
 510  *
 511  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 512  * functions which must match the way they are locked/unlocked outside
 513  * of this macro.
 514  *
 515  * wake_up_locked() has to be called after changing any variable that could
 516  * change the result of the wait condition.
 517  *
 518  * The function will return -ERESTARTSYS if it was interrupted by a
 519  * signal and 0 if @condition evaluated to true.
 520  */
 521 #define wait_event_interruptible_locked(wq, condition)                  \
 522         ((condition)                                                    \
 523          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
 524
 525 /**
 526  * wait_event_interruptible_locked_irq - sleep until a condition gets true
 527  * @wq: the waitqueue to wait on
 528  * @condition: a C expression for the event to wait for
 529  *
 530  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 531  * @condition evaluates to true or a signal is received.
 532  * The @condition is checked each time the waitqueue @wq is woken up.
 533  *
 534  * It must be called with wq.lock being held.  This spinlock is
 535  * unlocked while sleeping but @condition testing is done while lock
 536  * is held and when this macro exits the lock is held.
 537  *
 538  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 539  * functions which must match the way they are locked/unlocked outside
 540  * of this macro.
 541  *
 542  * wake_up_locked() has to be called after changing any variable that could
 543  * change the result of the wait condition.
 544  *
 545  * The function will return -ERESTARTSYS if it was interrupted by a
 546  * signal and 0 if @condition evaluated to true.
 547  */
 548 #define wait_event_interruptible_locked_irq(wq, condition)              \
 549         ((condition)                                                    \
 550          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
 551
 552 /**
 553  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
 554  * @wq: the waitqueue to wait on
 555  * @condition: a C expression for the event to wait for
 556  *
 557  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 558  * @condition evaluates to true or a signal is received.
 559  * The @condition is checked each time the waitqueue @wq is woken up.
 560  *
 561  * It must be called with wq.lock being held.  This spinlock is
 562  * unlocked while sleeping but @condition testing is done while lock
 563  * is held and when this macro exits the lock is held.
 564  *
 565  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 566  * functions which must match the way they are locked/unlocked outside
 567  * of this macro.
 568  *
 569  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 570  * set thus when other process waits process on the list if this
 571  * process is awaken further processes are not considered.
 572  *
 573  * wake_up_locked() has to be called after changing any variable that could
 574  * change the result of the wait condition.
 575  *
 576  * The function will return -ERESTARTSYS if it was interrupted by a
 577  * signal and 0 if @condition evaluated to true.
 578  */
 579 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
 580         ((condition)                                                    \
 581          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
 582
 583 /**
 584  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
 585  * @wq: the waitqueue to wait on
 586  * @condition: a C expression for the event to wait for
 587  *
 588  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 589  * @condition evaluates to true or a signal is received.
 590  * The @condition is checked each time the waitqueue @wq is woken up.
 591  *
 592  * It must be called with wq.lock being held.  This spinlock is
 593  * unlocked while sleeping but @condition testing is done while lock
 594  * is held and when this macro exits the lock is held.
 595  *
 596  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 597  * functions which must match the way they are locked/unlocked outside
 598  * of this macro.
 599  *
 600  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 601  * set thus when other process waits process on the list if this
 602  * process is awaken further processes are not considered.
 603  *
 604  * wake_up_locked() has to be called after changing any variable that could
 605  * change the result of the wait condition.
 606  *
 607  * The function will return -ERESTARTSYS if it was interrupted by a
 608  * signal and 0 if @condition evaluated to true.
 609  */
 610 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
 611         ((condition)                                                    \
 612          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
 613
 614
 615 #define __wait_event_killable(wq, condition)                            \
 616         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
 617
 618 /**
 619  * wait_event_killable - sleep until a condition gets true
 620  * @wq: the waitqueue to wait on
 621  * @condition: a C expression for the event to wait for
 622  *
 623  * The process is put to sleep (TASK_KILLABLE) until the
 624  * @condition evaluates to true or a signal is received.
 625  * The @condition is checked each time the waitqueue @wq is woken up.
 626  *
 627  * wake_up() has to be called after changing any variable that could
 628  * change the result of the wait condition.
 629  *
 630  * The function will return -ERESTARTSYS if it was interrupted by a
 631  * signal and 0 if @condition evaluated to true.
 632  */
 633 #define wait_event_killable(wq, condition)                              \
 634 ({                                                                      \
 635         int __ret = 0;                                                  \
 636         if (!(condition))                                               \
 637                 __ret = __wait_event_killable(wq, condition);           \
 638         __ret;                                                          \
 639 })
 640
 641
 642 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 643         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 644                             spin_unlock_irq(&lock);                     \
 645                             cmd;                                        \
 646                             schedule();                                 \
 647                             spin_lock_irq(&lock))
 648
 649 /**
 650  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
 651  *                           condition is checked under the lock. This
 652  *                           is expected to be called with the lock
 653  *                           taken.
 654  * @wq: the waitqueue to wait on
 655  * @condition: a C expression for the event to wait for
 656  * @lock: a locked spinlock_t, which will be released before cmd
 657  *        and schedule() and reacquired afterwards.
 658  * @cmd: a command which is invoked outside the critical section before
 659  *       sleep
 660  *
 661  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 662  * @condition evaluates to true. The @condition is checked each time
 663  * the waitqueue @wq is woken up.
 664  *
 665  * wake_up() has to be called after changing any variable that could
 666  * change the result of the wait condition.
 667  *
 668  * This is supposed to be called while holding the lock. The lock is
 669  * dropped before invoking the cmd and going to sleep and is reacquired
 670  * afterwards.
 671  */
 672 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
 673 do {                                                                    \
 674         if (condition)                                                  \
 675                 break;                                                  \
 676         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 677 } while (0)
 678
 679 /**
 680  * wait_event_lock_irq - sleep until a condition gets true. The
 681  *                       condition is checked under the lock. This
 682  *                       is expected to be called with the lock
 683  *                       taken.
 684  * @wq: the waitqueue to wait on
 685  * @condition: a C expression for the event to wait for
 686  * @lock: a locked spinlock_t, which will be released before schedule()
 687  *        and reacquired afterwards.
 688  *
 689  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 690  * @condition evaluates to true. The @condition is checked each time
 691  * the waitqueue @wq is woken up.
 692  *
 693  * wake_up() has to be called after changing any variable that could
 694  * change the result of the wait condition.
 695  *
 696  * This is supposed to be called while holding the lock. The lock is
 697  * dropped before going to sleep and is reacquired afterwards.
 698  */
 699 #define wait_event_lock_irq(wq, condition, lock)                        \
 700 do {                                                                    \
 701         if (condition)                                                  \
 702                 break;                                                  \
 703         __wait_event_lock_irq(wq, condition, lock, );                   \
 704 } while (0)
 705
 706
 707 #define __wait_event_interruptible_lock_irq(wq, condition, lock, cmd)   \
 708         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
 709                       spin_unlock_irq(&lock);                           \
 710                       cmd;                                              \
 711                       schedule();                                       \
 712                       spin_lock_irq(&lock))
 713
 714 /**
 715  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
 716  *              The condition is checked under the lock. This is expected to
 717  *              be called with the lock taken.
 718  * @wq: the waitqueue to wait on
 719  * @condition: a C expression for the event to wait for
 720  * @lock: a locked spinlock_t, which will be released before cmd and
 721  *        schedule() and reacquired afterwards.
 722  * @cmd: a command which is invoked outside the critical section before
 723  *       sleep
 724  *
 725  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 726  * @condition evaluates to true or a signal is received. The @condition is
 727  * checked each time the waitqueue @wq is woken up.
 728  *
 729  * wake_up() has to be called after changing any variable that could
 730  * change the result of the wait condition.
 731  *
 732  * This is supposed to be called while holding the lock. The lock is
 733  * dropped before invoking the cmd and going to sleep and is reacquired
 734  * afterwards.
 735  *
 736  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 737  * and 0 if @condition evaluated to true.
 738  */
 739 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
 740 ({                                                                      \
 741         int __ret = 0;                                                  \
 742         if (!(condition))                                               \
 743                 __ret = __wait_event_interruptible_lock_irq(wq,         \
 744                                                 condition, lock, cmd);  \
 745         __ret;                                                          \
 746 })
 747
 748 /**
 749  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
 750  *              The condition is checked under the lock. This is expected
 751  *              to be called with the lock taken.
 752  * @wq: the waitqueue to wait on
 753  * @condition: a C expression for the event to wait for
 754  * @lock: a locked spinlock_t, which will be released before schedule()
 755  *        and reacquired afterwards.
 756  *
 757  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 758  * @condition evaluates to true or signal is received. The @condition is
 759  * checked each time the waitqueue @wq is woken up.
 760  *
 761  * wake_up() has to be called after changing any variable that could
 762  * change the result of the wait condition.
 763  *
 764  * This is supposed to be called while holding the lock. The lock is
 765  * dropped before going to sleep and is reacquired afterwards.
 766  *
 767  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 768  * and 0 if @condition evaluated to true.
 769  */
 770 #define wait_event_interruptible_lock_irq(wq, condition, lock)          \
 771 ({                                                                      \
 772         int __ret = 0;                                                  \
 773         if (!(condition))                                               \
 774                 __ret = __wait_event_interruptible_lock_irq(wq,         \
 775                                                 condition, lock,);      \
 776         __ret;                                                          \
 777 })
 778
 779 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
 780                                                     lock, timeout)      \
 781         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 782                       TASK_INTERRUPTIBLE, 0, timeout,                   \
 783                       spin_unlock_irq(&lock);                           \
 784                       __ret = schedule_timeout(__ret);                  \
 785                       spin_lock_irq(&lock));
 786
 787 /**
 788  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
 789  *              true or a timeout elapses. The condition is checked under
 790  *              the lock. This is expected to be called with the lock taken.
 791  * @wq: the waitqueue to wait on
 792  * @condition: a C expression for the event to wait for
 793  * @lock: a locked spinlock_t, which will be released before schedule()
 794  *        and reacquired afterwards.
 795  * @timeout: timeout, in jiffies
 796  *
 797  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 798  * @condition evaluates to true or signal is received. The @condition is
 799  * checked each time the waitqueue @wq is woken up.
 800  *
 801  * wake_up() has to be called after changing any variable that could
 802  * change the result of the wait condition.
 803  *
 804  * This is supposed to be called while holding the lock. The lock is
 805  * dropped before going to sleep and is reacquired afterwards.
 806  *
 807  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
 808  * was interrupted by a signal, and the remaining jiffies otherwise
 809  * if the condition evaluated to true before the timeout elapsed.
 810  */
 811 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
 812                                                   timeout)              \
 813 ({                                                                      \
 814         long __ret = timeout;                                           \
 815         if (!___wait_cond_timeout(condition))                           \
 816                 __ret = __wait_event_interruptible_lock_irq_timeout(    \
 817                                         wq, condition, lock, timeout);  \
 818         __ret;                                                          \
 819 })
 820
 821 /*
 822  * Waitqueues which are removed from the waitqueue_head at wakeup time
 823  */
 824 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
 825 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
 826 long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state);
 827 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
 828 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key);
 829 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 830 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 831
 832 #define DEFINE_WAIT_FUNC(name, function)                                \
 833         wait_queue_t name = {                                           \
 834                 .private        = current,                              \
 835                 .func           = function,                             \
 836                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
 837         }
 838
 839 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
 840
 841 #define DEFINE_WAIT_BIT(name, word, bit)                                \
 842         struct wait_bit_queue name = {                                  \
 843                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
 844                 .wait   = {                                             \
 845                         .private        = current,                      \
 846                         .func           = wake_bit_function,            \
 847                         .task_list      =                               \
 848                                 LIST_HEAD_INIT((name).wait.task_list),  \
 849                 },                                                      \
 850         }
 851
 852 #define init_wait(wait)                                                 \
 853         do {                                                            \
 854                 (wait)->private = current;                              \
 855                 (wait)->func = autoremove_wake_function;                \
 856                 INIT_LIST_HEAD(&(wait)->task_list);                     \
 857                 (wait)->flags = 0;                                      \
 858         } while (0)
 859
 860
 861 extern int bit_wait(struct wait_bit_key *);
 862 extern int bit_wait_io(struct wait_bit_key *);
 863 extern int bit_wait_timeout(struct wait_bit_key *);
 864 extern int bit_wait_io_timeout(struct wait_bit_key *);
 865
 866 /**
 867  * wait_on_bit - wait for a bit to be cleared
 868  * @word: the word being waited on, a kernel virtual address
 869  * @bit: the bit of the word being waited on
 870  * @mode: the task state to sleep in
 871  *
 872  * There is a standard hashed waitqueue table for generic use. This
 873  * is the part of the hashtable's accessor API that waits on a bit.
 874  * For instance, if one were to have waiters on a bitflag, one would
 875  * call wait_on_bit() in threads waiting for the bit to clear.
 876  * One uses wait_on_bit() where one is waiting for the bit to clear,
 877  * but has no intention of setting it.
 878  * Returned value will be zero if the bit was cleared, or non-zero
 879  * if the process received a signal and the mode permitted wakeup
 880  * on that signal.
 881  */
 882 static inline int
 883 wait_on_bit(void *word, int bit, unsigned mode)
 884 {
 885         if (!test_bit(bit, word))
 886                 return 0;
 887         return out_of_line_wait_on_bit(word, bit,
 888                                        bit_wait,
 889                                        mode);
 890 }
 891
 892 /**
 893  * wait_on_bit_io - wait for a bit to be cleared
 894  * @word: the word being waited on, a kernel virtual address
 895  * @bit: the bit of the word being waited on
 896  * @mode: the task state to sleep in
 897  *
 898  * Use the standard hashed waitqueue table to wait for a bit
 899  * to be cleared.  This is similar to wait_on_bit(), but calls
 900  * io_schedule() instead of schedule() for the actual waiting.
 901  *
 902  * Returned value will be zero if the bit was cleared, or non-zero
 903  * if the process received a signal and the mode permitted wakeup
 904  * on that signal.
 905  */
 906 static inline int
 907 wait_on_bit_io(void *word, int bit, unsigned mode)
 908 {
 909         if (!test_bit(bit, word))
 910                 return 0;
 911         return out_of_line_wait_on_bit(word, bit,
 912                                        bit_wait_io,
 913                                        mode);
 914 }
 915
 916 /**
 917  * wait_on_bit_action - wait for a bit to be cleared
 918  * @word: the word being waited on, a kernel virtual address
 919  * @bit: the bit of the word being waited on
 920  * @action: the function used to sleep, which may take special actions
 921  * @mode: the task state to sleep in
 922  *
 923  * Use the standard hashed waitqueue table to wait for a bit
 924  * to be cleared, and allow the waiting action to be specified.
 925  * This is like wait_on_bit() but allows fine control of how the waiting
 926  * is done.
 927  *
 928  * Returned value will be zero if the bit was cleared, or non-zero
 929  * if the process received a signal and the mode permitted wakeup
 930  * on that signal.
 931  */
 932 static inline int
 933 wait_on_bit_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
 934 {
 935         if (!test_bit(bit, word))
 936                 return 0;
 937         return out_of_line_wait_on_bit(word, bit, action, mode);
 938 }
 939
 940 /**
 941  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
 942  * @word: the word being waited on, a kernel virtual address
 943  * @bit: the bit of the word being waited on
 944  * @mode: the task state to sleep in
 945  *
 946  * There is a standard hashed waitqueue table for generic use. This
 947  * is the part of the hashtable's accessor API that waits on a bit
 948  * when one intends to set it, for instance, trying to lock bitflags.
 949  * For instance, if one were to have waiters trying to set bitflag
 950  * and waiting for it to clear before setting it, one would call
 951  * wait_on_bit() in threads waiting to be able to set the bit.
 952  * One uses wait_on_bit_lock() where one is waiting for the bit to
 953  * clear with the intention of setting it, and when done, clearing it.
 954  *
 955  * Returns zero if the bit was (eventually) found to be clear and was
 956  * set.  Returns non-zero if a signal was delivered to the process and
 957  * the @mode allows that signal to wake the process.
 958  */
 959 static inline int
 960 wait_on_bit_lock(void *word, int bit, unsigned mode)
 961 {
 962         if (!test_and_set_bit(bit, word))
 963                 return 0;
 964         return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode);
 965 }
 966
 967 /**
 968  * wait_on_bit_lock_io - wait for a bit to be cleared, when wanting to set it
 969  * @word: the word being waited on, a kernel virtual address
 970  * @bit: the bit of the word being waited on
 971  * @mode: the task state to sleep in
 972  *
 973  * Use the standard hashed waitqueue table to wait for a bit
 974  * to be cleared and then to atomically set it.  This is similar
 975  * to wait_on_bit(), but calls io_schedule() instead of schedule()
 976  * for the actual waiting.
 977  *
 978  * Returns zero if the bit was (eventually) found to be clear and was
 979  * set.  Returns non-zero if a signal was delivered to the process and
 980  * the @mode allows that signal to wake the process.
 981  */
 982 static inline int
 983 wait_on_bit_lock_io(void *word, int bit, unsigned mode)
 984 {
 985         if (!test_and_set_bit(bit, word))
 986                 return 0;
 987         return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode);
 988 }
 989
 990 /**
 991  * wait_on_bit_lock_action - wait for a bit to be cleared, when wanting to set it
 992  * @word: the word being waited on, a kernel virtual address
 993  * @bit: the bit of the word being waited on
 994  * @action: the function used to sleep, which may take special actions
 995  * @mode: the task state to sleep in
 996  *
 997  * Use the standard hashed waitqueue table to wait for a bit
 998  * to be cleared and then to set it, and allow the waiting action
 999  * to be specified.
1000  * This is like wait_on_bit() but allows fine control of how the waiting
1001  * is done.
1002  *
1003  * Returns zero if the bit was (eventually) found to be clear and was
1004  * set.  Returns non-zero if a signal was delivered to the process and
1005  * the @mode allows that signal to wake the process.
1006  */
1007 static inline int
1008 wait_on_bit_lock_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
1009 {
1010         if (!test_and_set_bit(bit, word))
1011                 return 0;
1012         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
1013 }
1014
1015 /**
1016  * wait_on_atomic_t - Wait for an atomic_t to become 0
1017  * @val: The atomic value being waited on, a kernel virtual address
1018  * @action: the function used to sleep, which may take special actions
1019  * @mode: the task state to sleep in
1020  *
1021  * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
1022  * the purpose of getting a waitqueue, but we set the key to a bit number
1023  * outside of the target 'word'.
1024  */
1025 static inline
1026 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
1027 {
1028         if (atomic_read(val) == 0)
1029                 return 0;
1030         return out_of_line_wait_on_atomic_t(val, action, mode);
1031 }
1032
1033 #endif /* _LINUX_WAIT_H */