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  * Returns:
 285  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 286  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 287  * or the remaining jiffies (at least 1) if the @condition evaluated
 288  * to %true before the @timeout elapsed.
 289  */
 290 #define wait_event_timeout(wq, condition, timeout)                      \
 291 ({                                                                      \
 292         long __ret = timeout;                                           \
 293         if (!___wait_cond_timeout(condition))                           \
 294                 __ret = __wait_event_timeout(wq, condition, timeout);   \
 295         __ret;                                                          \
 296 })
 297
 298 #define __wait_event_cmd(wq, condition, cmd1, cmd2)                     \
 299         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 300                             cmd1; schedule(); cmd2)
 301
 302 /**
 303  * wait_event_cmd - sleep until a condition gets true
 304  * @wq: the waitqueue to wait on
 305  * @condition: a C expression for the event to wait for
 306  * @cmd1: the command will be executed before sleep
 307  * @cmd2: the command will be executed after sleep
 308  *
 309  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 310  * @condition evaluates to true. The @condition is checked each time
 311  * the waitqueue @wq is woken up.
 312  *
 313  * wake_up() has to be called after changing any variable that could
 314  * change the result of the wait condition.
 315  */
 316 #define wait_event_cmd(wq, condition, cmd1, cmd2)                       \
 317 do {                                                                    \
 318         if (condition)                                                  \
 319                 break;                                                  \
 320         __wait_event_cmd(wq, condition, cmd1, cmd2);                    \
 321 } while (0)
 322
 323 #define __wait_event_interruptible(wq, condition)                       \
 324         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
 325                       schedule())
 326
 327 /**
 328  * wait_event_interruptible - sleep until a condition gets true
 329  * @wq: the waitqueue to wait on
 330  * @condition: a C expression for the event to wait for
 331  *
 332  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 333  * @condition evaluates to true or a signal is received.
 334  * The @condition is checked each time the waitqueue @wq is woken up.
 335  *
 336  * wake_up() has to be called after changing any variable that could
 337  * change the result of the wait condition.
 338  *
 339  * The function will return -ERESTARTSYS if it was interrupted by a
 340  * signal and 0 if @condition evaluated to true.
 341  */
 342 #define wait_event_interruptible(wq, condition)                         \
 343 ({                                                                      \
 344         int __ret = 0;                                                  \
 345         if (!(condition))                                               \
 346                 __ret = __wait_event_interruptible(wq, condition);      \
 347         __ret;                                                          \
 348 })
 349
 350 #define __wait_event_interruptible_timeout(wq, condition, timeout)      \
 351         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 352                       TASK_INTERRUPTIBLE, 0, timeout,                   \
 353                       __ret = schedule_timeout(__ret))
 354
 355 /**
 356  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 357  * @wq: the waitqueue to wait on
 358  * @condition: a C expression for the event to wait for
 359  * @timeout: timeout, in jiffies
 360  *
 361  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 362  * @condition evaluates to true or a signal is received.
 363  * The @condition is checked each time the waitqueue @wq is woken up.
 364  *
 365  * wake_up() has to be called after changing any variable that could
 366  * change the result of the wait condition.
 367  *
 368  * Returns:
 369  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 370  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 371  * the remaining jiffies (at least 1) if the @condition evaluated
 372  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
 373  * interrupted by a signal.
 374  */
 375 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
 376 ({                                                                      \
 377         long __ret = timeout;                                           \
 378         if (!___wait_cond_timeout(condition))                           \
 379                 __ret = __wait_event_interruptible_timeout(wq,          \
 380                                                 condition, timeout);    \
 381         __ret;                                                          \
 382 })
 383
 384 #define __wait_event_hrtimeout(wq, condition, timeout, state)           \
 385 ({                                                                      \
 386         int __ret = 0;                                                  \
 387         struct hrtimer_sleeper __t;                                     \
 388                                                                         \
 389         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
 390                               HRTIMER_MODE_REL);                        \
 391         hrtimer_init_sleeper(&__t, current);                            \
 392         if ((timeout).tv64 != KTIME_MAX)                                \
 393                 hrtimer_start_range_ns(&__t.timer, timeout,             \
 394                                        current->timer_slack_ns,         \
 395                                        HRTIMER_MODE_REL);               \
 396                                                                         \
 397         __ret = ___wait_event(wq, condition, state, 0, 0,               \
 398                 if (!__t.task) {                                        \
 399                         __ret = -ETIME;                                 \
 400                         break;                                          \
 401                 }                                                       \
 402                 schedule());                                            \
 403                                                                         \
 404         hrtimer_cancel(&__t.timer);                                     \
 405         destroy_hrtimer_on_stack(&__t.timer);                           \
 406         __ret;                                                          \
 407 })
 408
 409 /**
 410  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
 411  * @wq: the waitqueue to wait on
 412  * @condition: a C expression for the event to wait for
 413  * @timeout: timeout, as a ktime_t
 414  *
 415  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 416  * @condition evaluates to true or a signal is received.
 417  * The @condition is checked each time the waitqueue @wq is woken up.
 418  *
 419  * wake_up() has to be called after changing any variable that could
 420  * change the result of the wait condition.
 421  *
 422  * The function returns 0 if @condition became true, or -ETIME if the timeout
 423  * elapsed.
 424  */
 425 #define wait_event_hrtimeout(wq, condition, timeout)                    \
 426 ({                                                                      \
 427         int __ret = 0;                                                  \
 428         if (!(condition))                                               \
 429                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 430                                                TASK_UNINTERRUPTIBLE);   \
 431         __ret;                                                          \
 432 })
 433
 434 /**
 435  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
 436  * @wq: the waitqueue to wait on
 437  * @condition: a C expression for the event to wait for
 438  * @timeout: timeout, as a ktime_t
 439  *
 440  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 441  * @condition evaluates to true or a signal is received.
 442  * The @condition is checked each time the waitqueue @wq is woken up.
 443  *
 444  * wake_up() has to be called after changing any variable that could
 445  * change the result of the wait condition.
 446  *
 447  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
 448  * interrupted by a signal, or -ETIME if the timeout elapsed.
 449  */
 450 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
 451 ({                                                                      \
 452         long __ret = 0;                                                 \
 453         if (!(condition))                                               \
 454                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 455                                                TASK_INTERRUPTIBLE);     \
 456         __ret;                                                          \
 457 })
 458
 459 #define __wait_event_interruptible_exclusive(wq, condition)             \
 460         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
 461                       schedule())
 462
 463 #define wait_event_interruptible_exclusive(wq, condition)               \
 464 ({                                                                      \
 465         int __ret = 0;                                                  \
 466         if (!(condition))                                               \
 467                 __ret = __wait_event_interruptible_exclusive(wq, condition);\
 468         __ret;                                                          \
 469 })
 470
 471
 472 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
 473 ({                                                                      \
 474         int __ret = 0;                                                  \
 475         DEFINE_WAIT(__wait);                                            \
 476         if (exclusive)                                                  \
 477                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
 478         do {                                                            \
 479                 if (likely(list_empty(&__wait.task_list)))              \
 480                         __add_wait_queue_tail(&(wq), &__wait);          \
 481                 set_current_state(TASK_INTERRUPTIBLE);                  \
 482                 if (signal_pending(current)) {                          \
 483                         __ret = -ERESTARTSYS;                           \
 484                         break;                                          \
 485                 }                                                       \
 486                 if (irq)                                                \
 487                         spin_unlock_irq(&(wq).lock);                    \
 488                 else                                                    \
 489                         spin_unlock(&(wq).lock);                        \
 490                 schedule();                                             \
 491                 if (irq)                                                \
 492                         spin_lock_irq(&(wq).lock);                      \
 493                 else                                                    \
 494                         spin_lock(&(wq).lock);                          \
 495         } while (!(condition));                                         \
 496         __remove_wait_queue(&(wq), &__wait);                            \
 497         __set_current_state(TASK_RUNNING);                              \
 498         __ret;                                                          \
 499 })
 500
 501
 502 /**
 503  * wait_event_interruptible_locked - sleep until a condition gets true
 504  * @wq: the waitqueue to wait on
 505  * @condition: a C expression for the event to wait for
 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  * It must be called with wq.lock being held.  This spinlock is
 512  * unlocked while sleeping but @condition testing is done while lock
 513  * is held and when this macro exits the lock is held.
 514  *
 515  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 516  * functions which must match the way they are locked/unlocked outside
 517  * of this macro.
 518  *
 519  * wake_up_locked() has to be called after changing any variable that could
 520  * change the result of the wait condition.
 521  *
 522  * The function will return -ERESTARTSYS if it was interrupted by a
 523  * signal and 0 if @condition evaluated to true.
 524  */
 525 #define wait_event_interruptible_locked(wq, condition)                  \
 526         ((condition)                                                    \
 527          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
 528
 529 /**
 530  * wait_event_interruptible_locked_irq - sleep until a condition gets true
 531  * @wq: the waitqueue to wait on
 532  * @condition: a C expression for the event to wait for
 533  *
 534  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 535  * @condition evaluates to true or a signal is received.
 536  * The @condition is checked each time the waitqueue @wq is woken up.
 537  *
 538  * It must be called with wq.lock being held.  This spinlock is
 539  * unlocked while sleeping but @condition testing is done while lock
 540  * is held and when this macro exits the lock is held.
 541  *
 542  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 543  * functions which must match the way they are locked/unlocked outside
 544  * of this macro.
 545  *
 546  * wake_up_locked() has to be called after changing any variable that could
 547  * change the result of the wait condition.
 548  *
 549  * The function will return -ERESTARTSYS if it was interrupted by a
 550  * signal and 0 if @condition evaluated to true.
 551  */
 552 #define wait_event_interruptible_locked_irq(wq, condition)              \
 553         ((condition)                                                    \
 554          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
 555
 556 /**
 557  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
 558  * @wq: the waitqueue to wait on
 559  * @condition: a C expression for the event to wait for
 560  *
 561  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 562  * @condition evaluates to true or a signal is received.
 563  * The @condition is checked each time the waitqueue @wq is woken up.
 564  *
 565  * It must be called with wq.lock being held.  This spinlock is
 566  * unlocked while sleeping but @condition testing is done while lock
 567  * is held and when this macro exits the lock is held.
 568  *
 569  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 570  * functions which must match the way they are locked/unlocked outside
 571  * of this macro.
 572  *
 573  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 574  * set thus when other process waits process on the list if this
 575  * process is awaken further processes are not considered.
 576  *
 577  * wake_up_locked() has to be called after changing any variable that could
 578  * change the result of the wait condition.
 579  *
 580  * The function will return -ERESTARTSYS if it was interrupted by a
 581  * signal and 0 if @condition evaluated to true.
 582  */
 583 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
 584         ((condition)                                                    \
 585          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
 586
 587 /**
 588  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
 589  * @wq: the waitqueue to wait on
 590  * @condition: a C expression for the event to wait for
 591  *
 592  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 593  * @condition evaluates to true or a signal is received.
 594  * The @condition is checked each time the waitqueue @wq is woken up.
 595  *
 596  * It must be called with wq.lock being held.  This spinlock is
 597  * unlocked while sleeping but @condition testing is done while lock
 598  * is held and when this macro exits the lock is held.
 599  *
 600  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 601  * functions which must match the way they are locked/unlocked outside
 602  * of this macro.
 603  *
 604  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 605  * set thus when other process waits process on the list if this
 606  * process is awaken further processes are not considered.
 607  *
 608  * wake_up_locked() has to be called after changing any variable that could
 609  * change the result of the wait condition.
 610  *
 611  * The function will return -ERESTARTSYS if it was interrupted by a
 612  * signal and 0 if @condition evaluated to true.
 613  */
 614 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
 615         ((condition)                                                    \
 616          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
 617
 618
 619 #define __wait_event_killable(wq, condition)                            \
 620         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
 621
 622 /**
 623  * wait_event_killable - sleep until a condition gets true
 624  * @wq: the waitqueue to wait on
 625  * @condition: a C expression for the event to wait for
 626  *
 627  * The process is put to sleep (TASK_KILLABLE) until the
 628  * @condition evaluates to true or a signal is received.
 629  * The @condition is checked each time the waitqueue @wq is woken up.
 630  *
 631  * wake_up() has to be called after changing any variable that could
 632  * change the result of the wait condition.
 633  *
 634  * The function will return -ERESTARTSYS if it was interrupted by a
 635  * signal and 0 if @condition evaluated to true.
 636  */
 637 #define wait_event_killable(wq, condition)                              \
 638 ({                                                                      \
 639         int __ret = 0;                                                  \
 640         if (!(condition))                                               \
 641                 __ret = __wait_event_killable(wq, condition);           \
 642         __ret;                                                          \
 643 })
 644
 645
 646 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 647         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 648                             spin_unlock_irq(&lock);                     \
 649                             cmd;                                        \
 650                             schedule();                                 \
 651                             spin_lock_irq(&lock))
 652
 653 /**
 654  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
 655  *                           condition is checked under the lock. This
 656  *                           is expected to be called with the lock
 657  *                           taken.
 658  * @wq: the waitqueue to wait on
 659  * @condition: a C expression for the event to wait for
 660  * @lock: a locked spinlock_t, which will be released before cmd
 661  *        and schedule() and reacquired afterwards.
 662  * @cmd: a command which is invoked outside the critical section before
 663  *       sleep
 664  *
 665  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 666  * @condition evaluates to true. The @condition is checked each time
 667  * the waitqueue @wq is woken up.
 668  *
 669  * wake_up() has to be called after changing any variable that could
 670  * change the result of the wait condition.
 671  *
 672  * This is supposed to be called while holding the lock. The lock is
 673  * dropped before invoking the cmd and going to sleep and is reacquired
 674  * afterwards.
 675  */
 676 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
 677 do {                                                                    \
 678         if (condition)                                                  \
 679                 break;                                                  \
 680         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 681 } while (0)
 682
 683 /**
 684  * wait_event_lock_irq - sleep until a condition gets true. The
 685  *                       condition is checked under the lock. This
 686  *                       is expected to be called with the lock
 687  *                       taken.
 688  * @wq: the waitqueue to wait on
 689  * @condition: a C expression for the event to wait for
 690  * @lock: a locked spinlock_t, which will be released before schedule()
 691  *        and reacquired afterwards.
 692  *
 693  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 694  * @condition evaluates to true. The @condition is checked each time
 695  * the waitqueue @wq is woken up.
 696  *
 697  * wake_up() has to be called after changing any variable that could
 698  * change the result of the wait condition.
 699  *
 700  * This is supposed to be called while holding the lock. The lock is
 701  * dropped before going to sleep and is reacquired afterwards.
 702  */
 703 #define wait_event_lock_irq(wq, condition, lock)                        \
 704 do {                                                                    \
 705         if (condition)                                                  \
 706                 break;                                                  \
 707         __wait_event_lock_irq(wq, condition, lock, );                   \
 708 } while (0)
 709
 710
 711 #define __wait_event_interruptible_lock_irq(wq, condition, lock, cmd)   \
 712         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
 713                       spin_unlock_irq(&lock);                           \
 714                       cmd;                                              \
 715                       schedule();                                       \
 716                       spin_lock_irq(&lock))
 717
 718 /**
 719  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
 720  *              The condition is checked under the lock. This is expected to
 721  *              be called with the lock taken.
 722  * @wq: the waitqueue to wait on
 723  * @condition: a C expression for the event to wait for
 724  * @lock: a locked spinlock_t, which will be released before cmd and
 725  *        schedule() and reacquired afterwards.
 726  * @cmd: a command which is invoked outside the critical section before
 727  *       sleep
 728  *
 729  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 730  * @condition evaluates to true or a signal is received. The @condition is
 731  * checked each time the waitqueue @wq is woken up.
 732  *
 733  * wake_up() has to be called after changing any variable that could
 734  * change the result of the wait condition.
 735  *
 736  * This is supposed to be called while holding the lock. The lock is
 737  * dropped before invoking the cmd and going to sleep and is reacquired
 738  * afterwards.
 739  *
 740  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 741  * and 0 if @condition evaluated to true.
 742  */
 743 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
 744 ({                                                                      \
 745         int __ret = 0;                                                  \
 746         if (!(condition))                                               \
 747                 __ret = __wait_event_interruptible_lock_irq(wq,         \
 748                                                 condition, lock, cmd);  \
 749         __ret;                                                          \
 750 })
 751
 752 /**
 753  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
 754  *              The condition is checked under the lock. This is expected
 755  *              to be called with the lock taken.
 756  * @wq: the waitqueue to wait on
 757  * @condition: a C expression for the event to wait for
 758  * @lock: a locked spinlock_t, which will be released before schedule()
 759  *        and reacquired afterwards.
 760  *
 761  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 762  * @condition evaluates to true or signal is received. The @condition is
 763  * checked each time the waitqueue @wq is woken up.
 764  *
 765  * wake_up() has to be called after changing any variable that could
 766  * change the result of the wait condition.
 767  *
 768  * This is supposed to be called while holding the lock. The lock is
 769  * dropped before going to sleep and is reacquired afterwards.
 770  *
 771  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 772  * and 0 if @condition evaluated to true.
 773  */
 774 #define wait_event_interruptible_lock_irq(wq, condition, lock)          \
 775 ({                                                                      \
 776         int __ret = 0;                                                  \
 777         if (!(condition))                                               \
 778                 __ret = __wait_event_interruptible_lock_irq(wq,         \
 779                                                 condition, lock,);      \
 780         __ret;                                                          \
 781 })
 782
 783 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
 784                                                     lock, timeout)      \
 785         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 786                       TASK_INTERRUPTIBLE, 0, timeout,                   \
 787                       spin_unlock_irq(&lock);                           \
 788                       __ret = schedule_timeout(__ret);                  \
 789                       spin_lock_irq(&lock));
 790
 791 /**
 792  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
 793  *              true or a timeout elapses. The condition is checked under
 794  *              the lock. This is expected to be called with the lock taken.
 795  * @wq: the waitqueue to wait on
 796  * @condition: a C expression for the event to wait for
 797  * @lock: a locked spinlock_t, which will be released before schedule()
 798  *        and reacquired afterwards.
 799  * @timeout: timeout, in jiffies
 800  *
 801  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 802  * @condition evaluates to true or signal is received. The @condition is
 803  * checked each time the waitqueue @wq is woken up.
 804  *
 805  * wake_up() has to be called after changing any variable that could
 806  * change the result of the wait condition.
 807  *
 808  * This is supposed to be called while holding the lock. The lock is
 809  * dropped before going to sleep and is reacquired afterwards.
 810  *
 811  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
 812  * was interrupted by a signal, and the remaining jiffies otherwise
 813  * if the condition evaluated to true before the timeout elapsed.
 814  */
 815 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
 816                                                   timeout)              \
 817 ({                                                                      \
 818         long __ret = timeout;                                           \
 819         if (!___wait_cond_timeout(condition))                           \
 820                 __ret = __wait_event_interruptible_lock_irq_timeout(    \
 821                                         wq, condition, lock, timeout);  \
 822         __ret;                                                          \
 823 })
 824
 825 /*
 826  * Waitqueues which are removed from the waitqueue_head at wakeup time
 827  */
 828 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
 829 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
 830 long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state);
 831 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
 832 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key);
 833 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 834 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 835
 836 #define DEFINE_WAIT_FUNC(name, function)                                \
 837         wait_queue_t name = {                                           \
 838                 .private        = current,                              \
 839                 .func           = function,                             \
 840                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
 841         }
 842
 843 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
 844
 845 #define DEFINE_WAIT_BIT(name, word, bit)                                \
 846         struct wait_bit_queue name = {                                  \
 847                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
 848                 .wait   = {                                             \
 849                         .private        = current,                      \
 850                         .func           = wake_bit_function,            \
 851                         .task_list      =                               \
 852                                 LIST_HEAD_INIT((name).wait.task_list),  \
 853                 },                                                      \
 854         }
 855
 856 #define init_wait(wait)                                                 \
 857         do {                                                            \
 858                 (wait)->private = current;                              \
 859                 (wait)->func = autoremove_wake_function;                \
 860                 INIT_LIST_HEAD(&(wait)->task_list);                     \
 861                 (wait)->flags = 0;                                      \
 862         } while (0)
 863
 864
 865 extern int bit_wait(struct wait_bit_key *);
 866 extern int bit_wait_io(struct wait_bit_key *);
 867 extern int bit_wait_timeout(struct wait_bit_key *);
 868 extern int bit_wait_io_timeout(struct wait_bit_key *);
 869
 870 /**
 871  * wait_on_bit - wait for a bit to be cleared
 872  * @word: the word being waited on, a kernel virtual address
 873  * @bit: the bit of the word being waited on
 874  * @mode: the task state to sleep in
 875  *
 876  * There is a standard hashed waitqueue table for generic use. This
 877  * is the part of the hashtable's accessor API that waits on a bit.
 878  * For instance, if one were to have waiters on a bitflag, one would
 879  * call wait_on_bit() in threads waiting for the bit to clear.
 880  * One uses wait_on_bit() where one is waiting for the bit to clear,
 881  * but has no intention of setting it.
 882  * Returned value will be zero if the bit was cleared, or non-zero
 883  * if the process received a signal and the mode permitted wakeup
 884  * on that signal.
 885  */
 886 static inline int
 887 wait_on_bit(void *word, int bit, unsigned mode)
 888 {
 889         if (!test_bit(bit, word))
 890                 return 0;
 891         return out_of_line_wait_on_bit(word, bit,
 892                                        bit_wait,
 893                                        mode);
 894 }
 895
 896 /**
 897  * wait_on_bit_io - wait for a bit to be cleared
 898  * @word: the word being waited on, a kernel virtual address
 899  * @bit: the bit of the word being waited on
 900  * @mode: the task state to sleep in
 901  *
 902  * Use the standard hashed waitqueue table to wait for a bit
 903  * to be cleared.  This is similar to wait_on_bit(), but calls
 904  * io_schedule() instead of schedule() for the actual waiting.
 905  *
 906  * Returned value will be zero if the bit was cleared, or non-zero
 907  * if the process received a signal and the mode permitted wakeup
 908  * on that signal.
 909  */
 910 static inline int
 911 wait_on_bit_io(void *word, int bit, unsigned mode)
 912 {
 913         if (!test_bit(bit, word))
 914                 return 0;
 915         return out_of_line_wait_on_bit(word, bit,
 916                                        bit_wait_io,
 917                                        mode);
 918 }
 919
 920 /**
 921  * wait_on_bit_action - wait for a bit to be cleared
 922  * @word: the word being waited on, a kernel virtual address
 923  * @bit: the bit of the word being waited on
 924  * @action: the function used to sleep, which may take special actions
 925  * @mode: the task state to sleep in
 926  *
 927  * Use the standard hashed waitqueue table to wait for a bit
 928  * to be cleared, and allow the waiting action to be specified.
 929  * This is like wait_on_bit() but allows fine control of how the waiting
 930  * is done.
 931  *
 932  * Returned value will be zero if the bit was cleared, or non-zero
 933  * if the process received a signal and the mode permitted wakeup
 934  * on that signal.
 935  */
 936 static inline int
 937 wait_on_bit_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
 938 {
 939         if (!test_bit(bit, word))
 940                 return 0;
 941         return out_of_line_wait_on_bit(word, bit, action, mode);
 942 }
 943
 944 /**
 945  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
 946  * @word: the word being waited on, a kernel virtual address
 947  * @bit: the bit of the word being waited on
 948  * @mode: the task state to sleep in
 949  *
 950  * There is a standard hashed waitqueue table for generic use. This
 951  * is the part of the hashtable's accessor API that waits on a bit
 952  * when one intends to set it, for instance, trying to lock bitflags.
 953  * For instance, if one were to have waiters trying to set bitflag
 954  * and waiting for it to clear before setting it, one would call
 955  * wait_on_bit() in threads waiting to be able to set the bit.
 956  * One uses wait_on_bit_lock() where one is waiting for the bit to
 957  * clear with the intention of setting it, and when done, clearing it.
 958  *
 959  * Returns zero if the bit was (eventually) found to be clear and was
 960  * set.  Returns non-zero if a signal was delivered to the process and
 961  * the @mode allows that signal to wake the process.
 962  */
 963 static inline int
 964 wait_on_bit_lock(void *word, int bit, unsigned mode)
 965 {
 966         if (!test_and_set_bit(bit, word))
 967                 return 0;
 968         return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode);
 969 }
 970
 971 /**
 972  * wait_on_bit_lock_io - wait for a bit to be cleared, when wanting to set it
 973  * @word: the word being waited on, a kernel virtual address
 974  * @bit: the bit of the word being waited on
 975  * @mode: the task state to sleep in
 976  *
 977  * Use the standard hashed waitqueue table to wait for a bit
 978  * to be cleared and then to atomically set it.  This is similar
 979  * to wait_on_bit(), but calls io_schedule() instead of schedule()
 980  * for the actual waiting.
 981  *
 982  * Returns zero if the bit was (eventually) found to be clear and was
 983  * set.  Returns non-zero if a signal was delivered to the process and
 984  * the @mode allows that signal to wake the process.
 985  */
 986 static inline int
 987 wait_on_bit_lock_io(void *word, int bit, unsigned mode)
 988 {
 989         if (!test_and_set_bit(bit, word))
 990                 return 0;
 991         return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode);
 992 }
 993
 994 /**
 995  * wait_on_bit_lock_action - wait for a bit to be cleared, when wanting to set it
 996  * @word: the word being waited on, a kernel virtual address
 997  * @bit: the bit of the word being waited on
 998  * @action: the function used to sleep, which may take special actions
 999  * @mode: the task state to sleep in
1000  *
1001  * Use the standard hashed waitqueue table to wait for a bit
1002  * to be cleared and then to set it, and allow the waiting action
1003  * to be specified.
1004  * This is like wait_on_bit() but allows fine control of how the waiting
1005  * is done.
1006  *
1007  * Returns zero if the bit was (eventually) found to be clear and was
1008  * set.  Returns non-zero if a signal was delivered to the process and
1009  * the @mode allows that signal to wake the process.
1010  */
1011 static inline int
1012 wait_on_bit_lock_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
1013 {
1014         if (!test_and_set_bit(bit, word))
1015                 return 0;
1016         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
1017 }
1018
1019 /**
1020  * wait_on_atomic_t - Wait for an atomic_t to become 0
1021  * @val: The atomic value being waited on, a kernel virtual address
1022  * @action: the function used to sleep, which may take special actions
1023  * @mode: the task state to sleep in
1024  *
1025  * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
1026  * the purpose of getting a waitqueue, but we set the key to a bit number
1027  * outside of the target 'word'.
1028  */
1029 static inline
1030 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
1031 {
1032         if (atomic_read(val) == 0)
1033                 return 0;
1034         return out_of_line_wait_on_atomic_t(val, action, mode);
1035 }
1036
1037 #endif /* _LINUX_WAIT_H */