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         ___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0,           \
 228                       ___wait_nop_ret, schedule())
 229
 230 /**
 231  * wait_event - sleep until a condition gets true
 232  * @wq: the waitqueue to wait on
 233  * @condition: a C expression for the event to wait for
 234  *
 235  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 236  * @condition evaluates to true. The @condition is checked each time
 237  * the waitqueue @wq is woken up.
 238  *
 239  * wake_up() has to be called after changing any variable that could
 240  * change the result of the wait condition.
 241  */
 242 #define wait_event(wq, condition)                                       \
 243 do {                                                                    \
 244         if (condition)                                                  \
 245                 break;                                                  \
 246         __wait_event(wq, condition);                                    \
 247 } while (0)
 248
 249 #define __wait_event_timeout(wq, condition, ret)                        \
 250         ___wait_event(wq, ___wait_cond_timeout(condition, ret),         \
 251                       TASK_UNINTERRUPTIBLE, 0, ret,                     \
 252                       ret = schedule_timeout(ret))
 253
 254 /**
 255  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 256  * @wq: the waitqueue to wait on
 257  * @condition: a C expression for the event to wait for
 258  * @timeout: timeout, in jiffies
 259  *
 260  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 261  * @condition evaluates to true. The @condition is checked each time
 262  * the waitqueue @wq is woken up.
 263  *
 264  * wake_up() has to be called after changing any variable that could
 265  * change the result of the wait condition.
 266  *
 267  * The function returns 0 if the @timeout elapsed, or the remaining
 268  * jiffies (at least 1) if the @condition evaluated to %true before
 269  * the @timeout elapsed.
 270  */
 271 #define wait_event_timeout(wq, condition, timeout)                      \
 272 ({                                                                      \
 273         long __ret = timeout;                                           \
 274         if (!(condition))                                               \
 275                 __wait_event_timeout(wq, condition, __ret);             \
 276         __ret;                                                          \
 277 })
 278
 279 #define __wait_event_interruptible(wq, condition, ret)                  \
 280         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, ret,        \
 281                       schedule())
 282
 283 /**
 284  * wait_event_interruptible - sleep until a condition gets true
 285  * @wq: the waitqueue to wait on
 286  * @condition: a C expression for the event to wait for
 287  *
 288  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 289  * @condition evaluates to true or a signal is received.
 290  * The @condition is checked each time the waitqueue @wq is woken up.
 291  *
 292  * wake_up() has to be called after changing any variable that could
 293  * change the result of the wait condition.
 294  *
 295  * The function will return -ERESTARTSYS if it was interrupted by a
 296  * signal and 0 if @condition evaluated to true.
 297  */
 298 #define wait_event_interruptible(wq, condition)                         \
 299 ({                                                                      \
 300         int __ret = 0;                                                  \
 301         if (!(condition))                                               \
 302                 __wait_event_interruptible(wq, condition, __ret);       \
 303         __ret;                                                          \
 304 })
 305
 306 #define __wait_event_interruptible_timeout(wq, condition, ret)          \
 307 do {                                                                    \
 308         DEFINE_WAIT(__wait);                                            \
 309                                                                         \
 310         for (;;) {                                                      \
 311                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 312                 if (___wait_cond_timeout(condition, ret))               \
 313                         break;                                          \
 314                 if (signal_pending(current)) {                          \
 315                         ret = -ERESTARTSYS;                             \
 316                         break;                                          \
 317                 }                                                       \
 318                 ret = schedule_timeout(ret);                            \
 319         }                                                               \
 320         finish_wait(&wq, &__wait);                                      \
 321 } while (0)
 322
 323 /**
 324  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 325  * @wq: the waitqueue to wait on
 326  * @condition: a C expression for the event to wait for
 327  * @timeout: timeout, in jiffies
 328  *
 329  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 330  * @condition evaluates to true or a signal is received.
 331  * The @condition is checked each time the waitqueue @wq is woken up.
 332  *
 333  * wake_up() has to be called after changing any variable that could
 334  * change the result of the wait condition.
 335  *
 336  * Returns:
 337  * 0 if the @timeout elapsed, -%ERESTARTSYS if it was interrupted by
 338  * a signal, or the remaining jiffies (at least 1) if the @condition
 339  * evaluated to %true before the @timeout elapsed.
 340  */
 341 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
 342 ({                                                                      \
 343         long __ret = timeout;                                           \
 344         if (!(condition))                                               \
 345                 __wait_event_interruptible_timeout(wq, condition, __ret); \
 346         __ret;                                                          \
 347 })
 348
 349 #define __wait_event_hrtimeout(wq, condition, timeout, state)           \
 350 ({                                                                      \
 351         int __ret = 0;                                                  \
 352         DEFINE_WAIT(__wait);                                            \
 353         struct hrtimer_sleeper __t;                                     \
 354                                                                         \
 355         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
 356                               HRTIMER_MODE_REL);                        \
 357         hrtimer_init_sleeper(&__t, current);                            \
 358         if ((timeout).tv64 != KTIME_MAX)                                \
 359                 hrtimer_start_range_ns(&__t.timer, timeout,             \
 360                                        current->timer_slack_ns,         \
 361                                        HRTIMER_MODE_REL);               \
 362                                                                         \
 363         for (;;) {                                                      \
 364                 prepare_to_wait(&wq, &__wait, state);                   \
 365                 if (condition)                                          \
 366                         break;                                          \
 367                 if (state == TASK_INTERRUPTIBLE &&                      \
 368                     signal_pending(current)) {                          \
 369                         __ret = -ERESTARTSYS;                           \
 370                         break;                                          \
 371                 }                                                       \
 372                 if (!__t.task) {                                        \
 373                         __ret = -ETIME;                                 \
 374                         break;                                          \
 375                 }                                                       \
 376                 schedule();                                             \
 377         }                                                               \
 378                                                                         \
 379         hrtimer_cancel(&__t.timer);                                     \
 380         destroy_hrtimer_on_stack(&__t.timer);                           \
 381         finish_wait(&wq, &__wait);                                      \
 382         __ret;                                                          \
 383 })
 384
 385 /**
 386  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
 387  * @wq: the waitqueue to wait on
 388  * @condition: a C expression for the event to wait for
 389  * @timeout: timeout, as a ktime_t
 390  *
 391  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 392  * @condition evaluates to true or a signal is received.
 393  * The @condition is checked each time the waitqueue @wq is woken up.
 394  *
 395  * wake_up() has to be called after changing any variable that could
 396  * change the result of the wait condition.
 397  *
 398  * The function returns 0 if @condition became true, or -ETIME if the timeout
 399  * elapsed.
 400  */
 401 #define wait_event_hrtimeout(wq, condition, timeout)                    \
 402 ({                                                                      \
 403         int __ret = 0;                                                  \
 404         if (!(condition))                                               \
 405                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 406                                                TASK_UNINTERRUPTIBLE);   \
 407         __ret;                                                          \
 408 })
 409
 410 /**
 411  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
 412  * @wq: the waitqueue to wait on
 413  * @condition: a C expression for the event to wait for
 414  * @timeout: timeout, as a ktime_t
 415  *
 416  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 417  * @condition evaluates to true or a signal is received.
 418  * The @condition is checked each time the waitqueue @wq is woken up.
 419  *
 420  * wake_up() has to be called after changing any variable that could
 421  * change the result of the wait condition.
 422  *
 423  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
 424  * interrupted by a signal, or -ETIME if the timeout elapsed.
 425  */
 426 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
 427 ({                                                                      \
 428         long __ret = 0;                                                 \
 429         if (!(condition))                                               \
 430                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 431                                                TASK_INTERRUPTIBLE);     \
 432         __ret;                                                          \
 433 })
 434
 435 #define __wait_event_interruptible_exclusive(wq, condition, ret)        \
 436 do {                                                                    \
 437         __label__ __out;                                                \
 438         DEFINE_WAIT(__wait);                                            \
 439                                                                         \
 440         for (;;) {                                                      \
 441                 prepare_to_wait_exclusive(&wq, &__wait,                 \
 442                                         TASK_INTERRUPTIBLE);            \
 443                 if (condition)                                          \
 444                         break;                                          \
 445                 if (signal_pending(current)) {                          \
 446                         ret = -ERESTARTSYS;                             \
 447                         abort_exclusive_wait(&wq, &__wait,              \
 448                                 TASK_INTERRUPTIBLE, NULL);              \
 449                         goto __out;                                     \
 450                 }                                                       \
 451                 schedule();                                             \
 452         }                                                               \
 453         finish_wait(&wq, &__wait);                                      \
 454 __out:  ;                                                               \
 455 } while (0)
 456
 457 #define wait_event_interruptible_exclusive(wq, condition)               \
 458 ({                                                                      \
 459         int __ret = 0;                                                  \
 460         if (!(condition))                                               \
 461                 __wait_event_interruptible_exclusive(wq, condition, __ret);\
 462         __ret;                                                          \
 463 })
 464
 465
 466 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
 467 ({                                                                      \
 468         int __ret = 0;                                                  \
 469         DEFINE_WAIT(__wait);                                            \
 470         if (exclusive)                                                  \
 471                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
 472         do {                                                            \
 473                 if (likely(list_empty(&__wait.task_list)))              \
 474                         __add_wait_queue_tail(&(wq), &__wait);          \
 475                 set_current_state(TASK_INTERRUPTIBLE);                  \
 476                 if (signal_pending(current)) {                          \
 477                         __ret = -ERESTARTSYS;                           \
 478                         break;                                          \
 479                 }                                                       \
 480                 if (irq)                                                \
 481                         spin_unlock_irq(&(wq).lock);                    \
 482                 else                                                    \
 483                         spin_unlock(&(wq).lock);                        \
 484                 schedule();                                             \
 485                 if (irq)                                                \
 486                         spin_lock_irq(&(wq).lock);                      \
 487                 else                                                    \
 488                         spin_lock(&(wq).lock);                          \
 489         } while (!(condition));                                         \
 490         __remove_wait_queue(&(wq), &__wait);                            \
 491         __set_current_state(TASK_RUNNING);                              \
 492         __ret;                                                          \
 493 })
 494
 495
 496 /**
 497  * wait_event_interruptible_locked - sleep until a condition gets true
 498  * @wq: the waitqueue to wait on
 499  * @condition: a C expression for the event to wait for
 500  *
 501  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 502  * @condition evaluates to true or a signal is received.
 503  * The @condition is checked each time the waitqueue @wq is woken up.
 504  *
 505  * It must be called with wq.lock being held.  This spinlock is
 506  * unlocked while sleeping but @condition testing is done while lock
 507  * is held and when this macro exits the lock is held.
 508  *
 509  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 510  * functions which must match the way they are locked/unlocked outside
 511  * of this macro.
 512  *
 513  * wake_up_locked() has to be called after changing any variable that could
 514  * change the result of the wait condition.
 515  *
 516  * The function will return -ERESTARTSYS if it was interrupted by a
 517  * signal and 0 if @condition evaluated to true.
 518  */
 519 #define wait_event_interruptible_locked(wq, condition)                  \
 520         ((condition)                                                    \
 521          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
 522
 523 /**
 524  * wait_event_interruptible_locked_irq - sleep until a condition gets true
 525  * @wq: the waitqueue to wait on
 526  * @condition: a C expression for the event to wait for
 527  *
 528  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 529  * @condition evaluates to true or a signal is received.
 530  * The @condition is checked each time the waitqueue @wq is woken up.
 531  *
 532  * It must be called with wq.lock being held.  This spinlock is
 533  * unlocked while sleeping but @condition testing is done while lock
 534  * is held and when this macro exits the lock is held.
 535  *
 536  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 537  * functions which must match the way they are locked/unlocked outside
 538  * of this macro.
 539  *
 540  * wake_up_locked() has to be called after changing any variable that could
 541  * change the result of the wait condition.
 542  *
 543  * The function will return -ERESTARTSYS if it was interrupted by a
 544  * signal and 0 if @condition evaluated to true.
 545  */
 546 #define wait_event_interruptible_locked_irq(wq, condition)              \
 547         ((condition)                                                    \
 548          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
 549
 550 /**
 551  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
 552  * @wq: the waitqueue to wait on
 553  * @condition: a C expression for the event to wait for
 554  *
 555  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 556  * @condition evaluates to true or a signal is received.
 557  * The @condition is checked each time the waitqueue @wq is woken up.
 558  *
 559  * It must be called with wq.lock being held.  This spinlock is
 560  * unlocked while sleeping but @condition testing is done while lock
 561  * is held and when this macro exits the lock is held.
 562  *
 563  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 564  * functions which must match the way they are locked/unlocked outside
 565  * of this macro.
 566  *
 567  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 568  * set thus when other process waits process on the list if this
 569  * process is awaken further processes are not considered.
 570  *
 571  * wake_up_locked() has to be called after changing any variable that could
 572  * change the result of the wait condition.
 573  *
 574  * The function will return -ERESTARTSYS if it was interrupted by a
 575  * signal and 0 if @condition evaluated to true.
 576  */
 577 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
 578         ((condition)                                                    \
 579          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
 580
 581 /**
 582  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
 583  * @wq: the waitqueue to wait on
 584  * @condition: a C expression for the event to wait for
 585  *
 586  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 587  * @condition evaluates to true or a signal is received.
 588  * The @condition is checked each time the waitqueue @wq is woken up.
 589  *
 590  * It must be called with wq.lock being held.  This spinlock is
 591  * unlocked while sleeping but @condition testing is done while lock
 592  * is held and when this macro exits the lock is held.
 593  *
 594  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 595  * functions which must match the way they are locked/unlocked outside
 596  * of this macro.
 597  *
 598  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 599  * set thus when other process waits process on the list if this
 600  * process is awaken further processes are not considered.
 601  *
 602  * wake_up_locked() has to be called after changing any variable that could
 603  * change the result of the wait condition.
 604  *
 605  * The function will return -ERESTARTSYS if it was interrupted by a
 606  * signal and 0 if @condition evaluated to true.
 607  */
 608 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
 609         ((condition)                                                    \
 610          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
 611
 612
 613
 614 #define __wait_event_killable(wq, condition, ret)                       \
 615 do {                                                                    \
 616         DEFINE_WAIT(__wait);                                            \
 617                                                                         \
 618         for (;;) {                                                      \
 619                 prepare_to_wait(&wq, &__wait, TASK_KILLABLE);           \
 620                 if (condition)                                          \
 621                         break;                                          \
 622                 if (!fatal_signal_pending(current)) {                   \
 623                         schedule();                                     \
 624                         continue;                                       \
 625                 }                                                       \
 626                 ret = -ERESTARTSYS;                                     \
 627                 break;                                                  \
 628         }                                                               \
 629         finish_wait(&wq, &__wait);                                      \
 630 } while (0)
 631
 632 /**
 633  * wait_event_killable - sleep until a condition gets true
 634  * @wq: the waitqueue to wait on
 635  * @condition: a C expression for the event to wait for
 636  *
 637  * The process is put to sleep (TASK_KILLABLE) until the
 638  * @condition evaluates to true or a signal is received.
 639  * The @condition is checked each time the waitqueue @wq is woken up.
 640  *
 641  * wake_up() has to be called after changing any variable that could
 642  * change the result of the wait condition.
 643  *
 644  * The function will return -ERESTARTSYS if it was interrupted by a
 645  * signal and 0 if @condition evaluated to true.
 646  */
 647 #define wait_event_killable(wq, condition)                              \
 648 ({                                                                      \
 649         int __ret = 0;                                                  \
 650         if (!(condition))                                               \
 651                 __wait_event_killable(wq, condition, __ret);            \
 652         __ret;                                                          \
 653 })
 654
 655
 656 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 657 do {                                                                    \
 658         DEFINE_WAIT(__wait);                                            \
 659                                                                         \
 660         for (;;) {                                                      \
 661                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 662                 if (condition)                                          \
 663                         break;                                          \
 664                 spin_unlock_irq(&lock);                                 \
 665                 cmd;                                                    \
 666                 schedule();                                             \
 667                 spin_lock_irq(&lock);                                   \
 668         }                                                               \
 669         finish_wait(&wq, &__wait);                                      \
 670 } while (0)
 671
 672 /**
 673  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
 674  *                           condition is checked under the lock. This
 675  *                           is expected to be called with the lock
 676  *                           taken.
 677  * @wq: the waitqueue to wait on
 678  * @condition: a C expression for the event to wait for
 679  * @lock: a locked spinlock_t, which will be released before cmd
 680  *        and schedule() and reacquired afterwards.
 681  * @cmd: a command which is invoked outside the critical section before
 682  *       sleep
 683  *
 684  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 685  * @condition evaluates to true. The @condition is checked each time
 686  * the waitqueue @wq is woken up.
 687  *
 688  * wake_up() has to be called after changing any variable that could
 689  * change the result of the wait condition.
 690  *
 691  * This is supposed to be called while holding the lock. The lock is
 692  * dropped before invoking the cmd and going to sleep and is reacquired
 693  * afterwards.
 694  */
 695 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
 696 do {                                                                    \
 697         if (condition)                                                  \
 698                 break;                                                  \
 699         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 700 } while (0)
 701
 702 /**
 703  * wait_event_lock_irq - 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 schedule()
 710  *        and reacquired afterwards.
 711  *
 712  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 713  * @condition evaluates to true. The @condition is checked each time
 714  * the waitqueue @wq is woken up.
 715  *
 716  * wake_up() has to be called after changing any variable that could
 717  * change the result of the wait condition.
 718  *
 719  * This is supposed to be called while holding the lock. The lock is
 720  * dropped before going to sleep and is reacquired afterwards.
 721  */
 722 #define wait_event_lock_irq(wq, condition, lock)                        \
 723 do {                                                                    \
 724         if (condition)                                                  \
 725                 break;                                                  \
 726         __wait_event_lock_irq(wq, condition, lock, );                   \
 727 } while (0)
 728
 729
 730 #define __wait_event_interruptible_lock_irq(wq, condition,              \
 731                                             lock, ret, cmd)             \
 732 do {                                                                    \
 733         DEFINE_WAIT(__wait);                                            \
 734                                                                         \
 735         for (;;) {                                                      \
 736                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 737                 if (condition)                                          \
 738                         break;                                          \
 739                 if (signal_pending(current)) {                          \
 740                         ret = -ERESTARTSYS;                             \
 741                         break;                                          \
 742                 }                                                       \
 743                 spin_unlock_irq(&lock);                                 \
 744                 cmd;                                                    \
 745                 schedule();                                             \
 746                 spin_lock_irq(&lock);                                   \
 747         }                                                               \
 748         finish_wait(&wq, &__wait);                                      \
 749 } while (0)
 750
 751 /**
 752  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
 753  *              The condition is checked under the lock. This is expected to
 754  *              be called with the lock taken.
 755  * @wq: the waitqueue to wait on
 756  * @condition: a C expression for the event to wait for
 757  * @lock: a locked spinlock_t, which will be released before cmd and
 758  *        schedule() and reacquired afterwards.
 759  * @cmd: a command which is invoked outside the critical section before
 760  *       sleep
 761  *
 762  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 763  * @condition evaluates to true or a signal is received. The @condition is
 764  * checked each time the waitqueue @wq is woken up.
 765  *
 766  * wake_up() has to be called after changing any variable that could
 767  * change the result of the wait condition.
 768  *
 769  * This is supposed to be called while holding the lock. The lock is
 770  * dropped before invoking the cmd and going to sleep and is reacquired
 771  * afterwards.
 772  *
 773  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 774  * and 0 if @condition evaluated to true.
 775  */
 776 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
 777 ({                                                                      \
 778         int __ret = 0;                                                  \
 779                                                                         \
 780         if (!(condition))                                               \
 781                 __wait_event_interruptible_lock_irq(wq, condition,      \
 782                                                     lock, __ret, cmd);  \
 783         __ret;                                                          \
 784 })
 785
 786 /**
 787  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
 788  *              The condition is checked under the lock. This is expected
 789  *              to be called with the lock taken.
 790  * @wq: the waitqueue to wait on
 791  * @condition: a C expression for the event to wait for
 792  * @lock: a locked spinlock_t, which will be released before schedule()
 793  *        and reacquired afterwards.
 794  *
 795  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 796  * @condition evaluates to true or signal is received. The @condition is
 797  * checked each time the waitqueue @wq is woken up.
 798  *
 799  * wake_up() has to be called after changing any variable that could
 800  * change the result of the wait condition.
 801  *
 802  * This is supposed to be called while holding the lock. The lock is
 803  * dropped before going to sleep and is reacquired afterwards.
 804  *
 805  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 806  * and 0 if @condition evaluated to true.
 807  */
 808 #define wait_event_interruptible_lock_irq(wq, condition, lock)          \
 809 ({                                                                      \
 810         int __ret = 0;                                                  \
 811                                                                         \
 812         if (!(condition))                                               \
 813                 __wait_event_interruptible_lock_irq(wq, condition,      \
 814                                                     lock, __ret, );     \
 815         __ret;                                                          \
 816 })
 817
 818 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
 819                                                     lock, ret)          \
 820 do {                                                                    \
 821         DEFINE_WAIT(__wait);                                            \
 822                                                                         \
 823         for (;;) {                                                      \
 824                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 825                 if (___wait_cond_timeout(condition, ret))               \
 826                         break;                                          \
 827                 if (signal_pending(current)) {                          \
 828                         ret = -ERESTARTSYS;                             \
 829                         break;                                          \
 830                 }                                                       \
 831                 spin_unlock_irq(&lock);                                 \
 832                 ret = schedule_timeout(ret);                            \
 833                 spin_lock_irq(&lock);                                   \
 834         }                                                               \
 835         finish_wait(&wq, &__wait);                                      \
 836 } while (0)
 837
 838 /**
 839  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets true or a timeout elapses.
 840  *              The condition is checked under the lock. This is expected
 841  *              to be called with the lock taken.
 842  * @wq: the waitqueue to wait on
 843  * @condition: a C expression for the event to wait for
 844  * @lock: a locked spinlock_t, which will be released before schedule()
 845  *        and reacquired afterwards.
 846  * @timeout: timeout, in jiffies
 847  *
 848  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 849  * @condition evaluates to true or signal is received. The @condition is
 850  * checked each time the waitqueue @wq is woken up.
 851  *
 852  * wake_up() has to be called after changing any variable that could
 853  * change the result of the wait condition.
 854  *
 855  * This is supposed to be called while holding the lock. The lock is
 856  * dropped before going to sleep and is reacquired afterwards.
 857  *
 858  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
 859  * was interrupted by a signal, and the remaining jiffies otherwise
 860  * if the condition evaluated to true before the timeout elapsed.
 861  */
 862 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
 863                                                   timeout)              \
 864 ({                                                                      \
 865         int __ret = timeout;                                            \
 866                                                                         \
 867         if (!(condition))                                               \
 868                 __wait_event_interruptible_lock_irq_timeout(            \
 869                                         wq, condition, lock, __ret);    \
 870         __ret;                                                          \
 871 })
 872
 873
 874 /*
 875  * These are the old interfaces to sleep waiting for an event.
 876  * They are racy.  DO NOT use them, use the wait_event* interfaces above.
 877  * We plan to remove these interfaces.
 878  */
 879 extern void sleep_on(wait_queue_head_t *q);
 880 extern long sleep_on_timeout(wait_queue_head_t *q,
 881                                       signed long timeout);
 882 extern void interruptible_sleep_on(wait_queue_head_t *q);
 883 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
 884                                            signed long timeout);
 885
 886 /*
 887  * Waitqueues which are removed from the waitqueue_head at wakeup time
 888  */
 889 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
 890 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
 891 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
 892 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
 893                         unsigned int mode, void *key);
 894 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 895 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 896
 897 #define DEFINE_WAIT_FUNC(name, function)                                \
 898         wait_queue_t name = {                                           \
 899                 .private        = current,                              \
 900                 .func           = function,                             \
 901                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
 902         }
 903
 904 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
 905
 906 #define DEFINE_WAIT_BIT(name, word, bit)                                \
 907         struct wait_bit_queue name = {                                  \
 908                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
 909                 .wait   = {                                             \
 910                         .private        = current,                      \
 911                         .func           = wake_bit_function,            \
 912                         .task_list      =                               \
 913                                 LIST_HEAD_INIT((name).wait.task_list),  \
 914                 },                                                      \
 915         }
 916
 917 #define init_wait(wait)                                                 \
 918         do {                                                            \
 919                 (wait)->private = current;                              \
 920                 (wait)->func = autoremove_wake_function;                \
 921                 INIT_LIST_HEAD(&(wait)->task_list);                     \
 922                 (wait)->flags = 0;                                      \
 923         } while (0)
 924
 925 /**
 926  * wait_on_bit - wait for a bit to be cleared
 927  * @word: the word being waited on, a kernel virtual address
 928  * @bit: the bit of the word being waited on
 929  * @action: the function used to sleep, which may take special actions
 930  * @mode: the task state to sleep in
 931  *
 932  * There is a standard hashed waitqueue table for generic use. This
 933  * is the part of the hashtable's accessor API that waits on a bit.
 934  * For instance, if one were to have waiters on a bitflag, one would
 935  * call wait_on_bit() in threads waiting for the bit to clear.
 936  * One uses wait_on_bit() where one is waiting for the bit to clear,
 937  * but has no intention of setting it.
 938  */
 939 static inline int wait_on_bit(void *word, int bit,
 940                                 int (*action)(void *), unsigned mode)
 941 {
 942         if (!test_bit(bit, word))
 943                 return 0;
 944         return out_of_line_wait_on_bit(word, bit, action, mode);
 945 }
 946
 947 /**
 948  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
 949  * @word: the word being waited on, a kernel virtual address
 950  * @bit: the bit of the word being waited on
 951  * @action: the function used to sleep, which may take special actions
 952  * @mode: the task state to sleep in
 953  *
 954  * There is a standard hashed waitqueue table for generic use. This
 955  * is the part of the hashtable's accessor API that waits on a bit
 956  * when one intends to set it, for instance, trying to lock bitflags.
 957  * For instance, if one were to have waiters trying to set bitflag
 958  * and waiting for it to clear before setting it, one would call
 959  * wait_on_bit() in threads waiting to be able to set the bit.
 960  * One uses wait_on_bit_lock() where one is waiting for the bit to
 961  * clear with the intention of setting it, and when done, clearing it.
 962  */
 963 static inline int wait_on_bit_lock(void *word, int bit,
 964                                 int (*action)(void *), 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, action, mode);
 969 }
 970
 971 /**
 972  * wait_on_atomic_t - Wait for an atomic_t to become 0
 973  * @val: The atomic value being waited on, a kernel virtual address
 974  * @action: the function used to sleep, which may take special actions
 975  * @mode: the task state to sleep in
 976  *
 977  * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
 978  * the purpose of getting a waitqueue, but we set the key to a bit number
 979  * outside of the target 'word'.
 980  */
 981 static inline
 982 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
 983 {
 984         if (atomic_read(val) == 0)
 985                 return 0;
 986         return out_of_line_wait_on_atomic_t(val, action, mode);
 987 }
 988
 989 #endif