include/linux/wait.h

   1 #ifndef _LINUX_WAIT_H
   2 #define _LINUX_WAIT_H
   3
   4
   5 #include <linux/list.h>
   6 #include <linux/stddef.h>
   7 #include <linux/spinlock.h>
   8 #include <asm/current.h>
   9 #include <uapi/linux/wait.h>
  10
  11 typedef struct __wait_queue wait_queue_t;
  12 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key);
  13 int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, void *key);
  14
  15 struct __wait_queue {
  16         unsigned int flags;
  17 #define WQ_FLAG_EXCLUSIVE       0x01
  18         void *private;
  19         wait_queue_func_t func;
  20         struct list_head task_list;
  21 };
  22
  23 struct wait_bit_key {
  24         void *flags;
  25         int bit_nr;
  26 #define WAIT_ATOMIC_T_BIT_NR -1
  27 };
  28
  29 struct wait_bit_queue {
  30         struct wait_bit_key key;
  31         wait_queue_t wait;
  32 };
  33
  34 struct __wait_queue_head {
  35         spinlock_t lock;
  36         struct list_head task_list;
  37 };
  38 typedef struct __wait_queue_head wait_queue_head_t;
  39
  40 struct task_struct;
  41
  42 /*
  43  * Macros for declaration and initialisaton of the datatypes
  44  */
  45
  46 #define __WAITQUEUE_INITIALIZER(name, tsk) {                            \
  47         .private        = tsk,                                          \
  48         .func           = default_wake_function,                        \
  49         .task_list      = { NULL, NULL } }
  50
  51 #define DECLARE_WAITQUEUE(name, tsk)                                    \
  52         wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
  53
  54 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                           \
  55         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),              \
  56         .task_list      = { &(name).task_list, &(name).task_list } }
  57
  58 #define DECLARE_WAIT_QUEUE_HEAD(name) \
  59         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
  60
  61 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)                           \
  62         { .flags = word, .bit_nr = bit, }
  63
  64 #define __WAIT_ATOMIC_T_KEY_INITIALIZER(p)                              \
  65         { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }
  66
  67 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
  68
  69 #define init_waitqueue_head(q)                          \
  70         do {                                            \
  71                 static struct lock_class_key __key;     \
  72                                                         \
  73                 __init_waitqueue_head((q), #q, &__key); \
  74         } while (0)
  75
  76 #ifdef CONFIG_LOCKDEP
  77 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
  78         ({ init_waitqueue_head(&name); name; })
  79 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
  80         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
  81 #else
  82 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
  83 #endif
  84
  85 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
  86 {
  87         q->flags = 0;
  88         q->private = p;
  89         q->func = default_wake_function;
  90 }
  91
  92 static inline void init_waitqueue_func_entry(wait_queue_t *q,
  93                                         wait_queue_func_t func)
  94 {
  95         q->flags = 0;
  96         q->private = NULL;
  97         q->func = func;
  98 }
  99
 100 static inline int waitqueue_active(wait_queue_head_t *q)
 101 {
 102         return !list_empty(&q->task_list);
 103 }
 104
 105 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 106 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
 107 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 108
 109 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
 110 {
 111         list_add(&new->task_list, &head->task_list);
 112 }
 113
 114 /*
 115  * Used for wake-one threads:
 116  */
 117 static inline void __add_wait_queue_exclusive(wait_queue_head_t *q,
 118                                               wait_queue_t *wait)
 119 {
 120         wait->flags |= WQ_FLAG_EXCLUSIVE;
 121         __add_wait_queue(q, wait);
 122 }
 123
 124 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
 125                                          wait_queue_t *new)
 126 {
 127         list_add_tail(&new->task_list, &head->task_list);
 128 }
 129
 130 static inline void __add_wait_queue_tail_exclusive(wait_queue_head_t *q,
 131                                               wait_queue_t *wait)
 132 {
 133         wait->flags |= WQ_FLAG_EXCLUSIVE;
 134         __add_wait_queue_tail(q, wait);
 135 }
 136
 137 static inline void __remove_wait_queue(wait_queue_head_t *head,
 138                                                         wait_queue_t *old)
 139 {
 140         list_del(&old->task_list);
 141 }
 142
 143 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 144 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
 145 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr,
 146                         void *key);
 147 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
 148 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
 149 void __wake_up_bit(wait_queue_head_t *, void *, int);
 150 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
 151 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
 152 void wake_up_bit(void *, int);
 153 void wake_up_atomic_t(atomic_t *);
 154 int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned);
 155 int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned);
 156 int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned);
 157 wait_queue_head_t *bit_waitqueue(void *, int);
 158
 159 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
 160 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
 161 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
 162 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL, 1)
 163 #define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)
 164
 165 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 166 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
 167 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
 168 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
 169
 170 /*
 171  * Wakeup macros to be used to report events to the targets.
 172  */
 173 #define wake_up_poll(x, m)                              \
 174         __wake_up(x, TASK_NORMAL, 1, (void *) (m))
 175 #define wake_up_locked_poll(x, m)                               \
 176         __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
 177 #define wake_up_interruptible_poll(x, m)                        \
 178         __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
 179 #define wake_up_interruptible_sync_poll(x, m)                           \
 180         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
 181
 182 #define ___wait_cond_timeout(condition, ret)                            \
 183 ({                                                                      \
 184         bool __cond = (condition);                                      \
 185         if (__cond && !ret)                                             \
 186                 ret = 1;                                                \
 187         __cond || !ret;                                                 \
 188 })
 189
 190 #define ___wait_signal_pending(state)                                   \
 191         ((state == TASK_INTERRUPTIBLE && signal_pending(current)) ||    \
 192          (state == TASK_KILLABLE && fatal_signal_pending(current)))
 193
 194 #define ___wait_nop_ret         int ret __always_unused
 195
 196 #define ___wait_event(wq, condition, state, exclusive, ret, cmd)        \
 197 do {                                                                    \
 198         __label__ __out;                                                \
 199         DEFINE_WAIT(__wait);                                            \
 200                                                                         \
 201         for (;;) {                                                      \
 202                 if (exclusive)                                          \
 203                         prepare_to_wait_exclusive(&wq, &__wait, state); \
 204                 else                                                    \
 205                         prepare_to_wait(&wq, &__wait, state);           \
 206                                                                         \
 207                 if (condition)                                          \
 208                         break;                                          \
 209                                                                         \
 210                 if (___wait_signal_pending(state)) {                    \
 211                         ret = -ERESTARTSYS;                             \
 212                         if (exclusive) {                                \
 213                                 abort_exclusive_wait(&wq, &__wait,      \
 214                                                      state, NULL);      \
 215                                 goto __out;                             \
 216                         }                                               \
 217                         break;                                          \
 218                 }                                                       \
 219                                                                         \
 220                 cmd;                                                    \
 221         }                                                               \
 222         finish_wait(&wq, &__wait);                                      \
 223 __out:  ;                                                               \
 224 } while (0)
 225
 226 #define __wait_event(wq, condition)                                     \
 227 do {                                                                    \
 228         DEFINE_WAIT(__wait);                                            \
 229                                                                         \
 230         for (;;) {                                                      \
 231                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 232                 if (condition)                                          \
 233                         break;                                          \
 234                 schedule();                                             \
 235         }                                                               \
 236         finish_wait(&wq, &__wait);                                      \
 237 } while (0)
 238
 239 /**
 240  * wait_event - sleep until a condition gets true
 241  * @wq: the waitqueue to wait on
 242  * @condition: a C expression for the event to wait for
 243  *
 244  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 245  * @condition evaluates to true. The @condition is checked each time
 246  * the waitqueue @wq is woken up.
 247  *
 248  * wake_up() has to be called after changing any variable that could
 249  * change the result of the wait condition.
 250  */
 251 #define wait_event(wq, condition)                                       \
 252 do {                                                                    \
 253         if (condition)                                                  \
 254                 break;                                                  \
 255         __wait_event(wq, condition);                                    \
 256 } while (0)
 257
 258 #define __wait_event_timeout(wq, condition, ret)                        \
 259 do {                                                                    \
 260         DEFINE_WAIT(__wait);                                            \
 261                                                                         \
 262         for (;;) {                                                      \
 263                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 264                 if (___wait_cond_timeout(condition, ret))               \
 265                         break;                                          \
 266                 ret = schedule_timeout(ret);                            \
 267         }                                                               \
 268         finish_wait(&wq, &__wait);                                      \
 269 } while (0)
 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 (!(condition))                                               \
 292                 __wait_event_timeout(wq, condition, __ret);             \
 293         __ret;                                                          \
 294 })
 295
 296 #define __wait_event_interruptible(wq, condition, ret)                  \
 297 do {                                                                    \
 298         DEFINE_WAIT(__wait);                                            \
 299                                                                         \
 300         for (;;) {                                                      \
 301                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 302                 if (condition)                                          \
 303                         break;                                          \
 304                 if (signal_pending(current)) {                          \
 305                         ret = -ERESTARTSYS;                             \
 306                         break;                                          \
 307                 }                                                       \
 308                 schedule();                                             \
 309         }                                                               \
 310         finish_wait(&wq, &__wait);                                      \
 311 } while (0)
 312
 313 /**
 314  * wait_event_interruptible - sleep until a condition gets true
 315  * @wq: the waitqueue to wait on
 316  * @condition: a C expression for the event to wait for
 317  *
 318  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 319  * @condition evaluates to true or a signal is received.
 320  * The @condition is checked each time the waitqueue @wq is woken up.
 321  *
 322  * wake_up() has to be called after changing any variable that could
 323  * change the result of the wait condition.
 324  *
 325  * The function will return -ERESTARTSYS if it was interrupted by a
 326  * signal and 0 if @condition evaluated to true.
 327  */
 328 #define wait_event_interruptible(wq, condition)                         \
 329 ({                                                                      \
 330         int __ret = 0;                                                  \
 331         if (!(condition))                                               \
 332                 __wait_event_interruptible(wq, condition, __ret);       \
 333         __ret;                                                          \
 334 })
 335
 336 #define __wait_event_interruptible_timeout(wq, condition, ret)          \
 337 do {                                                                    \
 338         DEFINE_WAIT(__wait);                                            \
 339                                                                         \
 340         for (;;) {                                                      \
 341                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 342                 if (___wait_cond_timeout(condition, ret))               \
 343                         break;                                          \
 344                 if (signal_pending(current)) {                          \
 345                         ret = -ERESTARTSYS;                             \
 346                         break;                                          \
 347                 }                                                       \
 348                 ret = schedule_timeout(ret);                            \
 349         }                                                               \
 350         finish_wait(&wq, &__wait);                                      \
 351 } while (0)
 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 (!(condition))                                               \
 375                 __wait_event_interruptible_timeout(wq, condition, __ret); \
 376         __ret;                                                          \
 377 })
 378
 379 #define __wait_event_hrtimeout(wq, condition, timeout, state)           \
 380 ({                                                                      \
 381         int __ret = 0;                                                  \
 382         DEFINE_WAIT(__wait);                                            \
 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         for (;;) {                                                      \
 394                 prepare_to_wait(&wq, &__wait, state);                   \
 395                 if (condition)                                          \
 396                         break;                                          \
 397                 if (state == TASK_INTERRUPTIBLE &&                      \
 398                     signal_pending(current)) {                          \
 399                         __ret = -ERESTARTSYS;                           \
 400                         break;                                          \
 401                 }                                                       \
 402                 if (!__t.task) {                                        \
 403                         __ret = -ETIME;                                 \
 404                         break;                                          \
 405                 }                                                       \
 406                 schedule();                                             \
 407         }                                                               \
 408                                                                         \
 409         hrtimer_cancel(&__t.timer);                                     \
 410         destroy_hrtimer_on_stack(&__t.timer);                           \
 411         finish_wait(&wq, &__wait);                                      \
 412         __ret;                                                          \
 413 })
 414
 415 /**
 416  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
 417  * @wq: the waitqueue to wait on
 418  * @condition: a C expression for the event to wait for
 419  * @timeout: timeout, as a ktime_t
 420  *
 421  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 422  * @condition evaluates to true or a signal is received.
 423  * The @condition is checked each time the waitqueue @wq is woken up.
 424  *
 425  * wake_up() has to be called after changing any variable that could
 426  * change the result of the wait condition.
 427  *
 428  * The function returns 0 if @condition became true, or -ETIME if the timeout
 429  * elapsed.
 430  */
 431 #define wait_event_hrtimeout(wq, condition, timeout)                    \
 432 ({                                                                      \
 433         int __ret = 0;                                                  \
 434         if (!(condition))                                               \
 435                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 436                                                TASK_UNINTERRUPTIBLE);   \
 437         __ret;                                                          \
 438 })
 439
 440 /**
 441  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
 442  * @wq: the waitqueue to wait on
 443  * @condition: a C expression for the event to wait for
 444  * @timeout: timeout, as a ktime_t
 445  *
 446  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 447  * @condition evaluates to true or a signal is received.
 448  * The @condition is checked each time the waitqueue @wq is woken up.
 449  *
 450  * wake_up() has to be called after changing any variable that could
 451  * change the result of the wait condition.
 452  *
 453  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
 454  * interrupted by a signal, or -ETIME if the timeout elapsed.
 455  */
 456 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
 457 ({                                                                      \
 458         long __ret = 0;                                                 \
 459         if (!(condition))                                               \
 460                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 461                                                TASK_INTERRUPTIBLE);     \
 462         __ret;                                                          \
 463 })
 464
 465 #define __wait_event_interruptible_exclusive(wq, condition, ret)        \
 466 do {                                                                    \
 467         __label__ __out;                                                \
 468         DEFINE_WAIT(__wait);                                            \
 469                                                                         \
 470         for (;;) {                                                      \
 471                 prepare_to_wait_exclusive(&wq, &__wait,                 \
 472                                         TASK_INTERRUPTIBLE);            \
 473                 if (condition)                                          \
 474                         break;                                          \
 475                 if (signal_pending(current)) {                          \
 476                         ret = -ERESTARTSYS;                             \
 477                         abort_exclusive_wait(&wq, &__wait,              \
 478                                 TASK_INTERRUPTIBLE, NULL);              \
 479                         goto __out;                                     \
 480                 }                                                       \
 481                 schedule();                                             \
 482         }                                                               \
 483         finish_wait(&wq, &__wait);                                      \
 484 __out:  ;                                                               \
 485 } while (0)
 486
 487 #define wait_event_interruptible_exclusive(wq, condition)               \
 488 ({                                                                      \
 489         int __ret = 0;                                                  \
 490         if (!(condition))                                               \
 491                 __wait_event_interruptible_exclusive(wq, condition, __ret);\
 492         __ret;                                                          \
 493 })
 494
 495
 496 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
 497 ({                                                                      \
 498         int __ret = 0;                                                  \
 499         DEFINE_WAIT(__wait);                                            \
 500         if (exclusive)                                                  \
 501                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
 502         do {                                                            \
 503                 if (likely(list_empty(&__wait.task_list)))              \
 504                         __add_wait_queue_tail(&(wq), &__wait);          \
 505                 set_current_state(TASK_INTERRUPTIBLE);                  \
 506                 if (signal_pending(current)) {                          \
 507                         __ret = -ERESTARTSYS;                           \
 508                         break;                                          \
 509                 }                                                       \
 510                 if (irq)                                                \
 511                         spin_unlock_irq(&(wq).lock);                    \
 512                 else                                                    \
 513                         spin_unlock(&(wq).lock);                        \
 514                 schedule();                                             \
 515                 if (irq)                                                \
 516                         spin_lock_irq(&(wq).lock);                      \
 517                 else                                                    \
 518                         spin_lock(&(wq).lock);                          \
 519         } while (!(condition));                                         \
 520         __remove_wait_queue(&(wq), &__wait);                            \
 521         __set_current_state(TASK_RUNNING);                              \
 522         __ret;                                                          \
 523 })
 524
 525
 526 /**
 527  * wait_event_interruptible_locked - sleep until a condition gets true
 528  * @wq: the waitqueue to wait on
 529  * @condition: a C expression for the event to wait for
 530  *
 531  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 532  * @condition evaluates to true or a signal is received.
 533  * The @condition is checked each time the waitqueue @wq is woken up.
 534  *
 535  * It must be called with wq.lock being held.  This spinlock is
 536  * unlocked while sleeping but @condition testing is done while lock
 537  * is held and when this macro exits the lock is held.
 538  *
 539  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 540  * functions which must match the way they are locked/unlocked outside
 541  * of this macro.
 542  *
 543  * wake_up_locked() has to be called after changing any variable that could
 544  * change the result of the wait condition.
 545  *
 546  * The function will return -ERESTARTSYS if it was interrupted by a
 547  * signal and 0 if @condition evaluated to true.
 548  */
 549 #define wait_event_interruptible_locked(wq, condition)                  \
 550         ((condition)                                                    \
 551          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
 552
 553 /**
 554  * wait_event_interruptible_locked_irq - sleep until a condition gets true
 555  * @wq: the waitqueue to wait on
 556  * @condition: a C expression for the event to wait for
 557  *
 558  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 559  * @condition evaluates to true or a signal is received.
 560  * The @condition is checked each time the waitqueue @wq is woken up.
 561  *
 562  * It must be called with wq.lock being held.  This spinlock is
 563  * unlocked while sleeping but @condition testing is done while lock
 564  * is held and when this macro exits the lock is held.
 565  *
 566  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 567  * functions which must match the way they are locked/unlocked outside
 568  * of this macro.
 569  *
 570  * wake_up_locked() has to be called after changing any variable that could
 571  * change the result of the wait condition.
 572  *
 573  * The function will return -ERESTARTSYS if it was interrupted by a
 574  * signal and 0 if @condition evaluated to true.
 575  */
 576 #define wait_event_interruptible_locked_irq(wq, condition)              \
 577         ((condition)                                                    \
 578          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
 579
 580 /**
 581  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
 582  * @wq: the waitqueue to wait on
 583  * @condition: a C expression for the event to wait for
 584  *
 585  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 586  * @condition evaluates to true or a signal is received.
 587  * The @condition is checked each time the waitqueue @wq is woken up.
 588  *
 589  * It must be called with wq.lock being held.  This spinlock is
 590  * unlocked while sleeping but @condition testing is done while lock
 591  * is held and when this macro exits the lock is held.
 592  *
 593  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 594  * functions which must match the way they are locked/unlocked outside
 595  * of this macro.
 596  *
 597  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 598  * set thus when other process waits process on the list if this
 599  * process is awaken further processes are not considered.
 600  *
 601  * wake_up_locked() has to be called after changing any variable that could
 602  * change the result of the wait condition.
 603  *
 604  * The function will return -ERESTARTSYS if it was interrupted by a
 605  * signal and 0 if @condition evaluated to true.
 606  */
 607 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
 608         ((condition)                                                    \
 609          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
 610
 611 /**
 612  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
 613  * @wq: the waitqueue to wait on
 614  * @condition: a C expression for the event to wait for
 615  *
 616  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 617  * @condition evaluates to true or a signal is received.
 618  * The @condition is checked each time the waitqueue @wq is woken up.
 619  *
 620  * It must be called with wq.lock being held.  This spinlock is
 621  * unlocked while sleeping but @condition testing is done while lock
 622  * is held and when this macro exits the lock is held.
 623  *
 624  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 625  * functions which must match the way they are locked/unlocked outside
 626  * of this macro.
 627  *
 628  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 629  * set thus when other process waits process on the list if this
 630  * process is awaken further processes are not considered.
 631  *
 632  * wake_up_locked() has to be called after changing any variable that could
 633  * change the result of the wait condition.
 634  *
 635  * The function will return -ERESTARTSYS if it was interrupted by a
 636  * signal and 0 if @condition evaluated to true.
 637  */
 638 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
 639         ((condition)                                                    \
 640          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
 641
 642
 643
 644 #define __wait_event_killable(wq, condition, ret)                       \
 645 do {                                                                    \
 646         DEFINE_WAIT(__wait);                                            \
 647                                                                         \
 648         for (;;) {                                                      \
 649                 prepare_to_wait(&wq, &__wait, TASK_KILLABLE);           \
 650                 if (condition)                                          \
 651                         break;                                          \
 652                 if (!fatal_signal_pending(current)) {                   \
 653                         schedule();                                     \
 654                         continue;                                       \
 655                 }                                                       \
 656                 ret = -ERESTARTSYS;                                     \
 657                 break;                                                  \
 658         }                                                               \
 659         finish_wait(&wq, &__wait);                                      \
 660 } while (0)
 661
 662 /**
 663  * wait_event_killable - sleep until a condition gets true
 664  * @wq: the waitqueue to wait on
 665  * @condition: a C expression for the event to wait for
 666  *
 667  * The process is put to sleep (TASK_KILLABLE) until the
 668  * @condition evaluates to true or a signal is received.
 669  * The @condition is checked each time the waitqueue @wq is woken up.
 670  *
 671  * wake_up() has to be called after changing any variable that could
 672  * change the result of the wait condition.
 673  *
 674  * The function will return -ERESTARTSYS if it was interrupted by a
 675  * signal and 0 if @condition evaluated to true.
 676  */
 677 #define wait_event_killable(wq, condition)                              \
 678 ({                                                                      \
 679         int __ret = 0;                                                  \
 680         if (!(condition))                                               \
 681                 __wait_event_killable(wq, condition, __ret);            \
 682         __ret;                                                          \
 683 })
 684
 685
 686 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 687 do {                                                                    \
 688         DEFINE_WAIT(__wait);                                            \
 689                                                                         \
 690         for (;;) {                                                      \
 691                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 692                 if (condition)                                          \
 693                         break;                                          \
 694                 spin_unlock_irq(&lock);                                 \
 695                 cmd;                                                    \
 696                 schedule();                                             \
 697                 spin_lock_irq(&lock);                                   \
 698         }                                                               \
 699         finish_wait(&wq, &__wait);                                      \
 700 } while (0)
 701
 702 /**
 703  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
 704  *                           condition is checked under the lock. This
 705  *                           is expected to be called with the lock
 706  *                           taken.
 707  * @wq: the waitqueue to wait on
 708  * @condition: a C expression for the event to wait for
 709  * @lock: a locked spinlock_t, which will be released before cmd
 710  *        and schedule() and reacquired afterwards.
 711  * @cmd: a command which is invoked outside the critical section before
 712  *       sleep
 713  *
 714  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 715  * @condition evaluates to true. The @condition is checked each time
 716  * the waitqueue @wq is woken up.
 717  *
 718  * wake_up() has to be called after changing any variable that could
 719  * change the result of the wait condition.
 720  *
 721  * This is supposed to be called while holding the lock. The lock is
 722  * dropped before invoking the cmd and going to sleep and is reacquired
 723  * afterwards.
 724  */
 725 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
 726 do {                                                                    \
 727         if (condition)                                                  \
 728                 break;                                                  \
 729         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 730 } while (0)
 731
 732 /**
 733  * wait_event_lock_irq - sleep until a condition gets true. The
 734  *                       condition is checked under the lock. This
 735  *                       is expected to be called with the lock
 736  *                       taken.
 737  * @wq: the waitqueue to wait on
 738  * @condition: a C expression for the event to wait for
 739  * @lock: a locked spinlock_t, which will be released before schedule()
 740  *        and reacquired afterwards.
 741  *
 742  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 743  * @condition evaluates to true. The @condition is checked each time
 744  * the waitqueue @wq is woken up.
 745  *
 746  * wake_up() has to be called after changing any variable that could
 747  * change the result of the wait condition.
 748  *
 749  * This is supposed to be called while holding the lock. The lock is
 750  * dropped before going to sleep and is reacquired afterwards.
 751  */
 752 #define wait_event_lock_irq(wq, condition, lock)                        \
 753 do {                                                                    \
 754         if (condition)                                                  \
 755                 break;                                                  \
 756         __wait_event_lock_irq(wq, condition, lock, );                   \
 757 } while (0)
 758
 759
 760 #define __wait_event_interruptible_lock_irq(wq, condition,              \
 761                                             lock, ret, cmd)             \
 762 do {                                                                    \
 763         DEFINE_WAIT(__wait);                                            \
 764                                                                         \
 765         for (;;) {                                                      \
 766                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 767                 if (condition)                                          \
 768                         break;                                          \
 769                 if (signal_pending(current)) {                          \
 770                         ret = -ERESTARTSYS;                             \
 771                         break;                                          \
 772                 }                                                       \
 773                 spin_unlock_irq(&lock);                                 \
 774                 cmd;                                                    \
 775                 schedule();                                             \
 776                 spin_lock_irq(&lock);                                   \
 777         }                                                               \
 778         finish_wait(&wq, &__wait);                                      \
 779 } while (0)
 780
 781 /**
 782  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
 783  *              The condition is checked under the lock. This is expected to
 784  *              be called with the lock taken.
 785  * @wq: the waitqueue to wait on
 786  * @condition: a C expression for the event to wait for
 787  * @lock: a locked spinlock_t, which will be released before cmd and
 788  *        schedule() and reacquired afterwards.
 789  * @cmd: a command which is invoked outside the critical section before
 790  *       sleep
 791  *
 792  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 793  * @condition evaluates to true or a signal is received. The @condition is
 794  * checked each time the waitqueue @wq is woken up.
 795  *
 796  * wake_up() has to be called after changing any variable that could
 797  * change the result of the wait condition.
 798  *
 799  * This is supposed to be called while holding the lock. The lock is
 800  * dropped before invoking the cmd and going to sleep and is reacquired
 801  * afterwards.
 802  *
 803  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 804  * and 0 if @condition evaluated to true.
 805  */
 806 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
 807 ({                                                                      \
 808         int __ret = 0;                                                  \
 809                                                                         \
 810         if (!(condition))                                               \
 811                 __wait_event_interruptible_lock_irq(wq, condition,      \
 812                                                     lock, __ret, cmd);  \
 813         __ret;                                                          \
 814 })
 815
 816 /**
 817  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
 818  *              The condition is checked under the lock. This is expected
 819  *              to be called with the lock taken.
 820  * @wq: the waitqueue to wait on
 821  * @condition: a C expression for the event to wait for
 822  * @lock: a locked spinlock_t, which will be released before schedule()
 823  *        and reacquired afterwards.
 824  *
 825  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 826  * @condition evaluates to true or signal is received. The @condition is
 827  * checked each time the waitqueue @wq is woken up.
 828  *
 829  * wake_up() has to be called after changing any variable that could
 830  * change the result of the wait condition.
 831  *
 832  * This is supposed to be called while holding the lock. The lock is
 833  * dropped before going to sleep and is reacquired afterwards.
 834  *
 835  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 836  * and 0 if @condition evaluated to true.
 837  */
 838 #define wait_event_interruptible_lock_irq(wq, condition, lock)          \
 839 ({                                                                      \
 840         int __ret = 0;                                                  \
 841                                                                         \
 842         if (!(condition))                                               \
 843                 __wait_event_interruptible_lock_irq(wq, condition,      \
 844                                                     lock, __ret, );     \
 845         __ret;                                                          \
 846 })
 847
 848 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
 849                                                     lock, ret)          \
 850 do {                                                                    \
 851         DEFINE_WAIT(__wait);                                            \
 852                                                                         \
 853         for (;;) {                                                      \
 854                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 855                 if (___wait_cond_timeout(condition, ret))               \
 856                         break;                                          \
 857                 if (signal_pending(current)) {                          \
 858                         ret = -ERESTARTSYS;                             \
 859                         break;                                          \
 860                 }                                                       \
 861                 spin_unlock_irq(&lock);                                 \
 862                 ret = schedule_timeout(ret);                            \
 863                 spin_lock_irq(&lock);                                   \
 864         }                                                               \
 865         finish_wait(&wq, &__wait);                                      \
 866 } while (0)
 867
 868 /**
 869  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets true or a timeout elapses.
 870  *              The condition is checked under the lock. This is expected
 871  *              to be called with the lock taken.
 872  * @wq: the waitqueue to wait on
 873  * @condition: a C expression for the event to wait for
 874  * @lock: a locked spinlock_t, which will be released before schedule()
 875  *        and reacquired afterwards.
 876  * @timeout: timeout, in jiffies
 877  *
 878  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 879  * @condition evaluates to true or signal is received. The @condition is
 880  * checked each time the waitqueue @wq is woken up.
 881  *
 882  * wake_up() has to be called after changing any variable that could
 883  * change the result of the wait condition.
 884  *
 885  * This is supposed to be called while holding the lock. The lock is
 886  * dropped before going to sleep and is reacquired afterwards.
 887  *
 888  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
 889  * was interrupted by a signal, and the remaining jiffies otherwise
 890  * if the condition evaluated to true before the timeout elapsed.
 891  */
 892 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
 893                                                   timeout)              \
 894 ({                                                                      \
 895         int __ret = timeout;                                            \
 896                                                                         \
 897         if (!(condition))                                               \
 898                 __wait_event_interruptible_lock_irq_timeout(            \
 899                                         wq, condition, lock, __ret);    \
 900         __ret;                                                          \
 901 })
 902
 903
 904 /*
 905  * These are the old interfaces to sleep waiting for an event.
 906  * They are racy.  DO NOT use them, use the wait_event* interfaces above.
 907  * We plan to remove these interfaces.
 908  */
 909 extern void sleep_on(wait_queue_head_t *q);
 910 extern long sleep_on_timeout(wait_queue_head_t *q,
 911                                       signed long timeout);
 912 extern void interruptible_sleep_on(wait_queue_head_t *q);
 913 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
 914                                            signed long timeout);
 915
 916 /*
 917  * Waitqueues which are removed from the waitqueue_head at wakeup time
 918  */
 919 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
 920 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
 921 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
 922 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
 923                         unsigned int mode, void *key);
 924 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 925 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 926
 927 #define DEFINE_WAIT_FUNC(name, function)                                \
 928         wait_queue_t name = {                                           \
 929                 .private        = current,                              \
 930                 .func           = function,                             \
 931                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
 932         }
 933
 934 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
 935
 936 #define DEFINE_WAIT_BIT(name, word, bit)                                \
 937         struct wait_bit_queue name = {                                  \
 938                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
 939                 .wait   = {                                             \
 940                         .private        = current,                      \
 941                         .func           = wake_bit_function,            \
 942                         .task_list      =                               \
 943                                 LIST_HEAD_INIT((name).wait.task_list),  \
 944                 },                                                      \
 945         }
 946
 947 #define init_wait(wait)                                                 \
 948         do {                                                            \
 949                 (wait)->private = current;                              \
 950                 (wait)->func = autoremove_wake_function;                \
 951                 INIT_LIST_HEAD(&(wait)->task_list);                     \
 952                 (wait)->flags = 0;                                      \
 953         } while (0)
 954
 955 /**
 956  * wait_on_bit - wait for a bit to be cleared
 957  * @word: the word being waited on, a kernel virtual address
 958  * @bit: the bit of the word being waited on
 959  * @action: the function used to sleep, which may take special actions
 960  * @mode: the task state to sleep in
 961  *
 962  * There is a standard hashed waitqueue table for generic use. This
 963  * is the part of the hashtable's accessor API that waits on a bit.
 964  * For instance, if one were to have waiters on a bitflag, one would
 965  * call wait_on_bit() in threads waiting for the bit to clear.
 966  * One uses wait_on_bit() where one is waiting for the bit to clear,
 967  * but has no intention of setting it.
 968  */
 969 static inline int wait_on_bit(void *word, int bit,
 970                                 int (*action)(void *), unsigned mode)
 971 {
 972         if (!test_bit(bit, word))
 973                 return 0;
 974         return out_of_line_wait_on_bit(word, bit, action, mode);
 975 }
 976
 977 /**
 978  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
 979  * @word: the word being waited on, a kernel virtual address
 980  * @bit: the bit of the word being waited on
 981  * @action: the function used to sleep, which may take special actions
 982  * @mode: the task state to sleep in
 983  *
 984  * There is a standard hashed waitqueue table for generic use. This
 985  * is the part of the hashtable's accessor API that waits on a bit
 986  * when one intends to set it, for instance, trying to lock bitflags.
 987  * For instance, if one were to have waiters trying to set bitflag
 988  * and waiting for it to clear before setting it, one would call
 989  * wait_on_bit() in threads waiting to be able to set the bit.
 990  * One uses wait_on_bit_lock() where one is waiting for the bit to
 991  * clear with the intention of setting it, and when done, clearing it.
 992  */
 993 static inline int wait_on_bit_lock(void *word, int bit,
 994                                 int (*action)(void *), unsigned mode)
 995 {
 996         if (!test_and_set_bit(bit, word))
 997                 return 0;
 998         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
 999 }
1000
1001 /**
1002  * wait_on_atomic_t - Wait for an atomic_t to become 0
1003  * @val: The atomic value being waited on, a kernel virtual address
1004  * @action: the function used to sleep, which may take special actions
1005  * @mode: the task state to sleep in
1006  *
1007  * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
1008  * the purpose of getting a waitqueue, but we set the key to a bit number
1009  * outside of the target 'word'.
1010  */
1011 static inline
1012 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
1013 {
1014         if (atomic_read(val) == 0)
1015                 return 0;
1016         return out_of_line_wait_on_atomic_t(val, action, mode);
1017 }
1018
1019 #endif