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 do {                                                                    \
 251         DEFINE_WAIT(__wait);                                            \
 252                                                                         \
 253         for (;;) {                                                      \
 254                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 255                 if (___wait_cond_timeout(condition, ret))               \
 256                         break;                                          \
 257                 ret = schedule_timeout(ret);                            \
 258         }                                                               \
 259         finish_wait(&wq, &__wait);                                      \
 260 } while (0)
 261
 262 /**
 263  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 264  * @wq: the waitqueue to wait on
 265  * @condition: a C expression for the event to wait for
 266  * @timeout: timeout, in jiffies
 267  *
 268  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 269  * @condition evaluates to true. The @condition is checked each time
 270  * the waitqueue @wq is woken up.
 271  *
 272  * wake_up() has to be called after changing any variable that could
 273  * change the result of the wait condition.
 274  *
 275  * The function returns 0 if the @timeout elapsed, or the remaining
 276  * jiffies (at least 1) if the @condition evaluated to %true before
 277  * the @timeout elapsed.
 278  */
 279 #define wait_event_timeout(wq, condition, timeout)                      \
 280 ({                                                                      \
 281         long __ret = timeout;                                           \
 282         if (!(condition))                                               \
 283                 __wait_event_timeout(wq, condition, __ret);             \
 284         __ret;                                                          \
 285 })
 286
 287 #define __wait_event_interruptible(wq, condition, ret)                  \
 288 do {                                                                    \
 289         DEFINE_WAIT(__wait);                                            \
 290                                                                         \
 291         for (;;) {                                                      \
 292                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 293                 if (condition)                                          \
 294                         break;                                          \
 295                 if (signal_pending(current)) {                          \
 296                         ret = -ERESTARTSYS;                             \
 297                         break;                                          \
 298                 }                                                       \
 299                 schedule();                                             \
 300         }                                                               \
 301         finish_wait(&wq, &__wait);                                      \
 302 } while (0)
 303
 304 /**
 305  * wait_event_interruptible - sleep until a condition gets true
 306  * @wq: the waitqueue to wait on
 307  * @condition: a C expression for the event to wait for
 308  *
 309  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 310  * @condition evaluates to true or a signal is received.
 311  * The @condition is checked each time the waitqueue @wq is woken up.
 312  *
 313  * wake_up() has to be called after changing any variable that could
 314  * change the result of the wait condition.
 315  *
 316  * The function will return -ERESTARTSYS if it was interrupted by a
 317  * signal and 0 if @condition evaluated to true.
 318  */
 319 #define wait_event_interruptible(wq, condition)                         \
 320 ({                                                                      \
 321         int __ret = 0;                                                  \
 322         if (!(condition))                                               \
 323                 __wait_event_interruptible(wq, condition, __ret);       \
 324         __ret;                                                          \
 325 })
 326
 327 #define __wait_event_interruptible_timeout(wq, condition, ret)          \
 328 do {                                                                    \
 329         DEFINE_WAIT(__wait);                                            \
 330                                                                         \
 331         for (;;) {                                                      \
 332                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 333                 if (___wait_cond_timeout(condition, ret))               \
 334                         break;                                          \
 335                 if (signal_pending(current)) {                          \
 336                         ret = -ERESTARTSYS;                             \
 337                         break;                                          \
 338                 }                                                       \
 339                 ret = schedule_timeout(ret);                            \
 340         }                                                               \
 341         finish_wait(&wq, &__wait);                                      \
 342 } while (0)
 343
 344 /**
 345  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 346  * @wq: the waitqueue to wait on
 347  * @condition: a C expression for the event to wait for
 348  * @timeout: timeout, in jiffies
 349  *
 350  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 351  * @condition evaluates to true or a signal is received.
 352  * The @condition is checked each time the waitqueue @wq is woken up.
 353  *
 354  * wake_up() has to be called after changing any variable that could
 355  * change the result of the wait condition.
 356  *
 357  * Returns:
 358  * 0 if the @timeout elapsed, -%ERESTARTSYS if it was interrupted by
 359  * a signal, or the remaining jiffies (at least 1) if the @condition
 360  * evaluated to %true before the @timeout elapsed.
 361  */
 362 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
 363 ({                                                                      \
 364         long __ret = timeout;                                           \
 365         if (!(condition))                                               \
 366                 __wait_event_interruptible_timeout(wq, condition, __ret); \
 367         __ret;                                                          \
 368 })
 369
 370 #define __wait_event_hrtimeout(wq, condition, timeout, state)           \
 371 ({                                                                      \
 372         int __ret = 0;                                                  \
 373         DEFINE_WAIT(__wait);                                            \
 374         struct hrtimer_sleeper __t;                                     \
 375                                                                         \
 376         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
 377                               HRTIMER_MODE_REL);                        \
 378         hrtimer_init_sleeper(&__t, current);                            \
 379         if ((timeout).tv64 != KTIME_MAX)                                \
 380                 hrtimer_start_range_ns(&__t.timer, timeout,             \
 381                                        current->timer_slack_ns,         \
 382                                        HRTIMER_MODE_REL);               \
 383                                                                         \
 384         for (;;) {                                                      \
 385                 prepare_to_wait(&wq, &__wait, state);                   \
 386                 if (condition)                                          \
 387                         break;                                          \
 388                 if (state == TASK_INTERRUPTIBLE &&                      \
 389                     signal_pending(current)) {                          \
 390                         __ret = -ERESTARTSYS;                           \
 391                         break;                                          \
 392                 }                                                       \
 393                 if (!__t.task) {                                        \
 394                         __ret = -ETIME;                                 \
 395                         break;                                          \
 396                 }                                                       \
 397                 schedule();                                             \
 398         }                                                               \
 399                                                                         \
 400         hrtimer_cancel(&__t.timer);                                     \
 401         destroy_hrtimer_on_stack(&__t.timer);                           \
 402         finish_wait(&wq, &__wait);                                      \
 403         __ret;                                                          \
 404 })
 405
 406 /**
 407  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
 408  * @wq: the waitqueue to wait on
 409  * @condition: a C expression for the event to wait for
 410  * @timeout: timeout, as a ktime_t
 411  *
 412  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 413  * @condition evaluates to true or a signal is received.
 414  * The @condition is checked each time the waitqueue @wq is woken up.
 415  *
 416  * wake_up() has to be called after changing any variable that could
 417  * change the result of the wait condition.
 418  *
 419  * The function returns 0 if @condition became true, or -ETIME if the timeout
 420  * elapsed.
 421  */
 422 #define wait_event_hrtimeout(wq, condition, timeout)                    \
 423 ({                                                                      \
 424         int __ret = 0;                                                  \
 425         if (!(condition))                                               \
 426                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 427                                                TASK_UNINTERRUPTIBLE);   \
 428         __ret;                                                          \
 429 })
 430
 431 /**
 432  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
 433  * @wq: the waitqueue to wait on
 434  * @condition: a C expression for the event to wait for
 435  * @timeout: timeout, as a ktime_t
 436  *
 437  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 438  * @condition evaluates to true or a signal is received.
 439  * The @condition is checked each time the waitqueue @wq is woken up.
 440  *
 441  * wake_up() has to be called after changing any variable that could
 442  * change the result of the wait condition.
 443  *
 444  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
 445  * interrupted by a signal, or -ETIME if the timeout elapsed.
 446  */
 447 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
 448 ({                                                                      \
 449         long __ret = 0;                                                 \
 450         if (!(condition))                                               \
 451                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 452                                                TASK_INTERRUPTIBLE);     \
 453         __ret;                                                          \
 454 })
 455
 456 #define __wait_event_interruptible_exclusive(wq, condition, ret)        \
 457 do {                                                                    \
 458         __label__ __out;                                                \
 459         DEFINE_WAIT(__wait);                                            \
 460                                                                         \
 461         for (;;) {                                                      \
 462                 prepare_to_wait_exclusive(&wq, &__wait,                 \
 463                                         TASK_INTERRUPTIBLE);            \
 464                 if (condition)                                          \
 465                         break;                                          \
 466                 if (signal_pending(current)) {                          \
 467                         ret = -ERESTARTSYS;                             \
 468                         abort_exclusive_wait(&wq, &__wait,              \
 469                                 TASK_INTERRUPTIBLE, NULL);              \
 470                         goto __out;                                     \
 471                 }                                                       \
 472                 schedule();                                             \
 473         }                                                               \
 474         finish_wait(&wq, &__wait);                                      \
 475 __out:  ;                                                               \
 476 } while (0)
 477
 478 #define wait_event_interruptible_exclusive(wq, condition)               \
 479 ({                                                                      \
 480         int __ret = 0;                                                  \
 481         if (!(condition))                                               \
 482                 __wait_event_interruptible_exclusive(wq, condition, __ret);\
 483         __ret;                                                          \
 484 })
 485
 486
 487 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
 488 ({                                                                      \
 489         int __ret = 0;                                                  \
 490         DEFINE_WAIT(__wait);                                            \
 491         if (exclusive)                                                  \
 492                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
 493         do {                                                            \
 494                 if (likely(list_empty(&__wait.task_list)))              \
 495                         __add_wait_queue_tail(&(wq), &__wait);          \
 496                 set_current_state(TASK_INTERRUPTIBLE);                  \
 497                 if (signal_pending(current)) {                          \
 498                         __ret = -ERESTARTSYS;                           \
 499                         break;                                          \
 500                 }                                                       \
 501                 if (irq)                                                \
 502                         spin_unlock_irq(&(wq).lock);                    \
 503                 else                                                    \
 504                         spin_unlock(&(wq).lock);                        \
 505                 schedule();                                             \
 506                 if (irq)                                                \
 507                         spin_lock_irq(&(wq).lock);                      \
 508                 else                                                    \
 509                         spin_lock(&(wq).lock);                          \
 510         } while (!(condition));                                         \
 511         __remove_wait_queue(&(wq), &__wait);                            \
 512         __set_current_state(TASK_RUNNING);                              \
 513         __ret;                                                          \
 514 })
 515
 516
 517 /**
 518  * wait_event_interruptible_locked - sleep until a condition gets true
 519  * @wq: the waitqueue to wait on
 520  * @condition: a C expression for the event to wait for
 521  *
 522  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 523  * @condition evaluates to true or a signal is received.
 524  * The @condition is checked each time the waitqueue @wq is woken up.
 525  *
 526  * It must be called with wq.lock being held.  This spinlock is
 527  * unlocked while sleeping but @condition testing is done while lock
 528  * is held and when this macro exits the lock is held.
 529  *
 530  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 531  * functions which must match the way they are locked/unlocked outside
 532  * of this macro.
 533  *
 534  * wake_up_locked() has to be called after changing any variable that could
 535  * change the result of the wait condition.
 536  *
 537  * The function will return -ERESTARTSYS if it was interrupted by a
 538  * signal and 0 if @condition evaluated to true.
 539  */
 540 #define wait_event_interruptible_locked(wq, condition)                  \
 541         ((condition)                                                    \
 542          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
 543
 544 /**
 545  * wait_event_interruptible_locked_irq - sleep until a condition gets true
 546  * @wq: the waitqueue to wait on
 547  * @condition: a C expression for the event to wait for
 548  *
 549  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 550  * @condition evaluates to true or a signal is received.
 551  * The @condition is checked each time the waitqueue @wq is woken up.
 552  *
 553  * It must be called with wq.lock being held.  This spinlock is
 554  * unlocked while sleeping but @condition testing is done while lock
 555  * is held and when this macro exits the lock is held.
 556  *
 557  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 558  * functions which must match the way they are locked/unlocked outside
 559  * of this macro.
 560  *
 561  * wake_up_locked() has to be called after changing any variable that could
 562  * change the result of the wait condition.
 563  *
 564  * The function will return -ERESTARTSYS if it was interrupted by a
 565  * signal and 0 if @condition evaluated to true.
 566  */
 567 #define wait_event_interruptible_locked_irq(wq, condition)              \
 568         ((condition)                                                    \
 569          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
 570
 571 /**
 572  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
 573  * @wq: the waitqueue to wait on
 574  * @condition: a C expression for the event to wait for
 575  *
 576  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 577  * @condition evaluates to true or a signal is received.
 578  * The @condition is checked each time the waitqueue @wq is woken up.
 579  *
 580  * It must be called with wq.lock being held.  This spinlock is
 581  * unlocked while sleeping but @condition testing is done while lock
 582  * is held and when this macro exits the lock is held.
 583  *
 584  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 585  * functions which must match the way they are locked/unlocked outside
 586  * of this macro.
 587  *
 588  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 589  * set thus when other process waits process on the list if this
 590  * process is awaken further processes are not considered.
 591  *
 592  * wake_up_locked() has to be called after changing any variable that could
 593  * change the result of the wait condition.
 594  *
 595  * The function will return -ERESTARTSYS if it was interrupted by a
 596  * signal and 0 if @condition evaluated to true.
 597  */
 598 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
 599         ((condition)                                                    \
 600          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
 601
 602 /**
 603  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
 604  * @wq: the waitqueue to wait on
 605  * @condition: a C expression for the event to wait for
 606  *
 607  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 608  * @condition evaluates to true or a signal is received.
 609  * The @condition is checked each time the waitqueue @wq is woken up.
 610  *
 611  * It must be called with wq.lock being held.  This spinlock is
 612  * unlocked while sleeping but @condition testing is done while lock
 613  * is held and when this macro exits the lock is held.
 614  *
 615  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 616  * functions which must match the way they are locked/unlocked outside
 617  * of this macro.
 618  *
 619  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 620  * set thus when other process waits process on the list if this
 621  * process is awaken further processes are not considered.
 622  *
 623  * wake_up_locked() has to be called after changing any variable that could
 624  * change the result of the wait condition.
 625  *
 626  * The function will return -ERESTARTSYS if it was interrupted by a
 627  * signal and 0 if @condition evaluated to true.
 628  */
 629 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
 630         ((condition)                                                    \
 631          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
 632
 633
 634
 635 #define __wait_event_killable(wq, condition, ret)                       \
 636 do {                                                                    \
 637         DEFINE_WAIT(__wait);                                            \
 638                                                                         \
 639         for (;;) {                                                      \
 640                 prepare_to_wait(&wq, &__wait, TASK_KILLABLE);           \
 641                 if (condition)                                          \
 642                         break;                                          \
 643                 if (!fatal_signal_pending(current)) {                   \
 644                         schedule();                                     \
 645                         continue;                                       \
 646                 }                                                       \
 647                 ret = -ERESTARTSYS;                                     \
 648                 break;                                                  \
 649         }                                                               \
 650         finish_wait(&wq, &__wait);                                      \
 651 } while (0)
 652
 653 /**
 654  * wait_event_killable - sleep until a condition gets true
 655  * @wq: the waitqueue to wait on
 656  * @condition: a C expression for the event to wait for
 657  *
 658  * The process is put to sleep (TASK_KILLABLE) until the
 659  * @condition evaluates to true or a signal is received.
 660  * The @condition is checked each time the waitqueue @wq is woken up.
 661  *
 662  * wake_up() has to be called after changing any variable that could
 663  * change the result of the wait condition.
 664  *
 665  * The function will return -ERESTARTSYS if it was interrupted by a
 666  * signal and 0 if @condition evaluated to true.
 667  */
 668 #define wait_event_killable(wq, condition)                              \
 669 ({                                                                      \
 670         int __ret = 0;                                                  \
 671         if (!(condition))                                               \
 672                 __wait_event_killable(wq, condition, __ret);            \
 673         __ret;                                                          \
 674 })
 675
 676
 677 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 678 do {                                                                    \
 679         DEFINE_WAIT(__wait);                                            \
 680                                                                         \
 681         for (;;) {                                                      \
 682                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 683                 if (condition)                                          \
 684                         break;                                          \
 685                 spin_unlock_irq(&lock);                                 \
 686                 cmd;                                                    \
 687                 schedule();                                             \
 688                 spin_lock_irq(&lock);                                   \
 689         }                                                               \
 690         finish_wait(&wq, &__wait);                                      \
 691 } while (0)
 692
 693 /**
 694  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
 695  *                           condition is checked under the lock. This
 696  *                           is expected to be called with the lock
 697  *                           taken.
 698  * @wq: the waitqueue to wait on
 699  * @condition: a C expression for the event to wait for
 700  * @lock: a locked spinlock_t, which will be released before cmd
 701  *        and schedule() and reacquired afterwards.
 702  * @cmd: a command which is invoked outside the critical section before
 703  *       sleep
 704  *
 705  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 706  * @condition evaluates to true. The @condition is checked each time
 707  * the waitqueue @wq is woken up.
 708  *
 709  * wake_up() has to be called after changing any variable that could
 710  * change the result of the wait condition.
 711  *
 712  * This is supposed to be called while holding the lock. The lock is
 713  * dropped before invoking the cmd and going to sleep and is reacquired
 714  * afterwards.
 715  */
 716 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
 717 do {                                                                    \
 718         if (condition)                                                  \
 719                 break;                                                  \
 720         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 721 } while (0)
 722
 723 /**
 724  * wait_event_lock_irq - sleep until a condition gets true. The
 725  *                       condition is checked under the lock. This
 726  *                       is expected to be called with the lock
 727  *                       taken.
 728  * @wq: the waitqueue to wait on
 729  * @condition: a C expression for the event to wait for
 730  * @lock: a locked spinlock_t, which will be released before schedule()
 731  *        and reacquired afterwards.
 732  *
 733  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 734  * @condition evaluates to true. The @condition is checked each time
 735  * the waitqueue @wq is woken up.
 736  *
 737  * wake_up() has to be called after changing any variable that could
 738  * change the result of the wait condition.
 739  *
 740  * This is supposed to be called while holding the lock. The lock is
 741  * dropped before going to sleep and is reacquired afterwards.
 742  */
 743 #define wait_event_lock_irq(wq, condition, lock)                        \
 744 do {                                                                    \
 745         if (condition)                                                  \
 746                 break;                                                  \
 747         __wait_event_lock_irq(wq, condition, lock, );                   \
 748 } while (0)
 749
 750
 751 #define __wait_event_interruptible_lock_irq(wq, condition,              \
 752                                             lock, ret, cmd)             \
 753 do {                                                                    \
 754         DEFINE_WAIT(__wait);                                            \
 755                                                                         \
 756         for (;;) {                                                      \
 757                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 758                 if (condition)                                          \
 759                         break;                                          \
 760                 if (signal_pending(current)) {                          \
 761                         ret = -ERESTARTSYS;                             \
 762                         break;                                          \
 763                 }                                                       \
 764                 spin_unlock_irq(&lock);                                 \
 765                 cmd;                                                    \
 766                 schedule();                                             \
 767                 spin_lock_irq(&lock);                                   \
 768         }                                                               \
 769         finish_wait(&wq, &__wait);                                      \
 770 } while (0)
 771
 772 /**
 773  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
 774  *              The condition is checked under the lock. This is expected to
 775  *              be called with the lock taken.
 776  * @wq: the waitqueue to wait on
 777  * @condition: a C expression for the event to wait for
 778  * @lock: a locked spinlock_t, which will be released before cmd and
 779  *        schedule() and reacquired afterwards.
 780  * @cmd: a command which is invoked outside the critical section before
 781  *       sleep
 782  *
 783  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 784  * @condition evaluates to true or a signal is received. The @condition is
 785  * checked each time the waitqueue @wq is woken up.
 786  *
 787  * wake_up() has to be called after changing any variable that could
 788  * change the result of the wait condition.
 789  *
 790  * This is supposed to be called while holding the lock. The lock is
 791  * dropped before invoking the cmd and going to sleep and is reacquired
 792  * afterwards.
 793  *
 794  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 795  * and 0 if @condition evaluated to true.
 796  */
 797 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
 798 ({                                                                      \
 799         int __ret = 0;                                                  \
 800                                                                         \
 801         if (!(condition))                                               \
 802                 __wait_event_interruptible_lock_irq(wq, condition,      \
 803                                                     lock, __ret, cmd);  \
 804         __ret;                                                          \
 805 })
 806
 807 /**
 808  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
 809  *              The condition is checked under the lock. This is expected
 810  *              to be called with the lock taken.
 811  * @wq: the waitqueue to wait on
 812  * @condition: a C expression for the event to wait for
 813  * @lock: a locked spinlock_t, which will be released before schedule()
 814  *        and reacquired afterwards.
 815  *
 816  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 817  * @condition evaluates to true or signal is received. The @condition is
 818  * checked each time the waitqueue @wq is woken up.
 819  *
 820  * wake_up() has to be called after changing any variable that could
 821  * change the result of the wait condition.
 822  *
 823  * This is supposed to be called while holding the lock. The lock is
 824  * dropped before going to sleep and is reacquired afterwards.
 825  *
 826  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 827  * and 0 if @condition evaluated to true.
 828  */
 829 #define wait_event_interruptible_lock_irq(wq, condition, lock)          \
 830 ({                                                                      \
 831         int __ret = 0;                                                  \
 832                                                                         \
 833         if (!(condition))                                               \
 834                 __wait_event_interruptible_lock_irq(wq, condition,      \
 835                                                     lock, __ret, );     \
 836         __ret;                                                          \
 837 })
 838
 839 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
 840                                                     lock, ret)          \
 841 do {                                                                    \
 842         DEFINE_WAIT(__wait);                                            \
 843                                                                         \
 844         for (;;) {                                                      \
 845                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 846                 if (___wait_cond_timeout(condition, ret))               \
 847                         break;                                          \
 848                 if (signal_pending(current)) {                          \
 849                         ret = -ERESTARTSYS;                             \
 850                         break;                                          \
 851                 }                                                       \
 852                 spin_unlock_irq(&lock);                                 \
 853                 ret = schedule_timeout(ret);                            \
 854                 spin_lock_irq(&lock);                                   \
 855         }                                                               \
 856         finish_wait(&wq, &__wait);                                      \
 857 } while (0)
 858
 859 /**
 860  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets true or a timeout elapses.
 861  *              The condition is checked under the lock. This is expected
 862  *              to be called with the lock taken.
 863  * @wq: the waitqueue to wait on
 864  * @condition: a C expression for the event to wait for
 865  * @lock: a locked spinlock_t, which will be released before schedule()
 866  *        and reacquired afterwards.
 867  * @timeout: timeout, in jiffies
 868  *
 869  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 870  * @condition evaluates to true or signal is received. The @condition is
 871  * checked each time the waitqueue @wq is woken up.
 872  *
 873  * wake_up() has to be called after changing any variable that could
 874  * change the result of the wait condition.
 875  *
 876  * This is supposed to be called while holding the lock. The lock is
 877  * dropped before going to sleep and is reacquired afterwards.
 878  *
 879  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
 880  * was interrupted by a signal, and the remaining jiffies otherwise
 881  * if the condition evaluated to true before the timeout elapsed.
 882  */
 883 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
 884                                                   timeout)              \
 885 ({                                                                      \
 886         int __ret = timeout;                                            \
 887                                                                         \
 888         if (!(condition))                                               \
 889                 __wait_event_interruptible_lock_irq_timeout(            \
 890                                         wq, condition, lock, __ret);    \
 891         __ret;                                                          \
 892 })
 893
 894
 895 /*
 896  * These are the old interfaces to sleep waiting for an event.
 897  * They are racy.  DO NOT use them, use the wait_event* interfaces above.
 898  * We plan to remove these interfaces.
 899  */
 900 extern void sleep_on(wait_queue_head_t *q);
 901 extern long sleep_on_timeout(wait_queue_head_t *q,
 902                                       signed long timeout);
 903 extern void interruptible_sleep_on(wait_queue_head_t *q);
 904 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
 905                                            signed long timeout);
 906
 907 /*
 908  * Waitqueues which are removed from the waitqueue_head at wakeup time
 909  */
 910 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
 911 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
 912 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
 913 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
 914                         unsigned int mode, void *key);
 915 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 916 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 917
 918 #define DEFINE_WAIT_FUNC(name, function)                                \
 919         wait_queue_t name = {                                           \
 920                 .private        = current,                              \
 921                 .func           = function,                             \
 922                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
 923         }
 924
 925 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
 926
 927 #define DEFINE_WAIT_BIT(name, word, bit)                                \
 928         struct wait_bit_queue name = {                                  \
 929                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
 930                 .wait   = {                                             \
 931                         .private        = current,                      \
 932                         .func           = wake_bit_function,            \
 933                         .task_list      =                               \
 934                                 LIST_HEAD_INIT((name).wait.task_list),  \
 935                 },                                                      \
 936         }
 937
 938 #define init_wait(wait)                                                 \
 939         do {                                                            \
 940                 (wait)->private = current;                              \
 941                 (wait)->func = autoremove_wake_function;                \
 942                 INIT_LIST_HEAD(&(wait)->task_list);                     \
 943                 (wait)->flags = 0;                                      \
 944         } while (0)
 945
 946 /**
 947  * wait_on_bit - wait for a bit to be cleared
 948  * @word: the word being waited on, a kernel virtual address
 949  * @bit: the bit of the word being waited on
 950  * @action: the function used to sleep, which may take special actions
 951  * @mode: the task state to sleep in
 952  *
 953  * There is a standard hashed waitqueue table for generic use. This
 954  * is the part of the hashtable's accessor API that waits on a bit.
 955  * For instance, if one were to have waiters on a bitflag, one would
 956  * call wait_on_bit() in threads waiting for the bit to clear.
 957  * One uses wait_on_bit() where one is waiting for the bit to clear,
 958  * but has no intention of setting it.
 959  */
 960 static inline int wait_on_bit(void *word, int bit,
 961                                 int (*action)(void *), unsigned mode)
 962 {
 963         if (!test_bit(bit, word))
 964                 return 0;
 965         return out_of_line_wait_on_bit(word, bit, action, mode);
 966 }
 967
 968 /**
 969  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
 970  * @word: the word being waited on, a kernel virtual address
 971  * @bit: the bit of the word being waited on
 972  * @action: the function used to sleep, which may take special actions
 973  * @mode: the task state to sleep in
 974  *
 975  * There is a standard hashed waitqueue table for generic use. This
 976  * is the part of the hashtable's accessor API that waits on a bit
 977  * when one intends to set it, for instance, trying to lock bitflags.
 978  * For instance, if one were to have waiters trying to set bitflag
 979  * and waiting for it to clear before setting it, one would call
 980  * wait_on_bit() in threads waiting to be able to set the bit.
 981  * One uses wait_on_bit_lock() where one is waiting for the bit to
 982  * clear with the intention of setting it, and when done, clearing it.
 983  */
 984 static inline int wait_on_bit_lock(void *word, int bit,
 985                                 int (*action)(void *), unsigned mode)
 986 {
 987         if (!test_and_set_bit(bit, word))
 988                 return 0;
 989         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
 990 }
 991
 992 /**
 993  * wait_on_atomic_t - Wait for an atomic_t to become 0
 994  * @val: The atomic value being waited on, a kernel virtual address
 995  * @action: the function used to sleep, which may take special actions
 996  * @mode: the task state to sleep in
 997  *
 998  * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
 999  * the purpose of getting a waitqueue, but we set the key to a bit number
1000  * outside of the target 'word'.
1001  */
1002 static inline
1003 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
1004 {
1005         if (atomic_read(val) == 0)
1006                 return 0;
1007         return out_of_line_wait_on_atomic_t(val, action, mode);
1008 }
1009
1010 #endif