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_event(wq, condition)                                     \
 183 do {                                                                    \
 184         DEFINE_WAIT(__wait);                                            \
 185                                                                         \
 186         for (;;) {                                                      \
 187                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 188                 if (condition)                                          \
 189                         break;                                          \
 190                 schedule();                                             \
 191         }                                                               \
 192         finish_wait(&wq, &__wait);                                      \
 193 } while (0)
 194
 195 /**
 196  * wait_event - sleep until a condition gets true
 197  * @wq: the waitqueue to wait on
 198  * @condition: a C expression for the event to wait for
 199  *
 200  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 201  * @condition evaluates to true. The @condition is checked each time
 202  * the waitqueue @wq is woken up.
 203  *
 204  * wake_up() has to be called after changing any variable that could
 205  * change the result of the wait condition.
 206  */
 207 #define wait_event(wq, condition)                                       \
 208 do {                                                                    \
 209         if (condition)                                                  \
 210                 break;                                                  \
 211         __wait_event(wq, condition);                                    \
 212 } while (0)
 213
 214 #define __wait_event_timeout(wq, condition, ret)                        \
 215 do {                                                                    \
 216         DEFINE_WAIT(__wait);                                            \
 217                                                                         \
 218         for (;;) {                                                      \
 219                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 220                 if (condition)                                          \
 221                         break;                                          \
 222                 ret = schedule_timeout(ret);                            \
 223                 if (!ret)                                               \
 224                         break;                                          \
 225         }                                                               \
 226         finish_wait(&wq, &__wait);                                      \
 227 } while (0)
 228
 229 /**
 230  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 231  * @wq: the waitqueue to wait on
 232  * @condition: a C expression for the event to wait for
 233  * @timeout: timeout, in jiffies
 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  * The function returns 0 if the @timeout elapsed, and the remaining
 243  * jiffies if the condition evaluated to true before the timeout elapsed.
 244  */
 245 #define wait_event_timeout(wq, condition, timeout)                      \
 246 ({                                                                      \
 247         long __ret = timeout;                                           \
 248         if (!(condition))                                               \
 249                 __wait_event_timeout(wq, condition, __ret);             \
 250         __ret;                                                          \
 251 })
 252
 253 #define __wait_event_interruptible(wq, condition, ret)                  \
 254 do {                                                                    \
 255         DEFINE_WAIT(__wait);                                            \
 256                                                                         \
 257         for (;;) {                                                      \
 258                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 259                 if (condition)                                          \
 260                         break;                                          \
 261                 if (!signal_pending(current)) {                         \
 262                         schedule();                                     \
 263                         continue;                                       \
 264                 }                                                       \
 265                 ret = -ERESTARTSYS;                                     \
 266                 break;                                                  \
 267         }                                                               \
 268         finish_wait(&wq, &__wait);                                      \
 269 } while (0)
 270
 271 /**
 272  * wait_event_interruptible - sleep until a condition gets true
 273  * @wq: the waitqueue to wait on
 274  * @condition: a C expression for the event to wait for
 275  *
 276  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 277  * @condition evaluates to true or a signal is received.
 278  * The @condition is checked each time the waitqueue @wq is woken up.
 279  *
 280  * wake_up() has to be called after changing any variable that could
 281  * change the result of the wait condition.
 282  *
 283  * The function will return -ERESTARTSYS if it was interrupted by a
 284  * signal and 0 if @condition evaluated to true.
 285  */
 286 #define wait_event_interruptible(wq, condition)                         \
 287 ({                                                                      \
 288         int __ret = 0;                                                  \
 289         if (!(condition))                                               \
 290                 __wait_event_interruptible(wq, condition, __ret);       \
 291         __ret;                                                          \
 292 })
 293
 294 #define __wait_event_interruptible_timeout(wq, condition, ret)          \
 295 do {                                                                    \
 296         DEFINE_WAIT(__wait);                                            \
 297                                                                         \
 298         for (;;) {                                                      \
 299                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 300                 if (condition)                                          \
 301                         break;                                          \
 302                 if (!signal_pending(current)) {                         \
 303                         ret = schedule_timeout(ret);                    \
 304                         if (!ret)                                       \
 305                                 break;                                  \
 306                         continue;                                       \
 307                 }                                                       \
 308                 ret = -ERESTARTSYS;                                     \
 309                 break;                                                  \
 310         }                                                               \
 311         finish_wait(&wq, &__wait);                                      \
 312 } while (0)
 313
 314 /**
 315  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 316  * @wq: the waitqueue to wait on
 317  * @condition: a C expression for the event to wait for
 318  * @timeout: timeout, in jiffies
 319  *
 320  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 321  * @condition evaluates to true or a signal is received.
 322  * The @condition is checked each time the waitqueue @wq is woken up.
 323  *
 324  * wake_up() has to be called after changing any variable that could
 325  * change the result of the wait condition.
 326  *
 327  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
 328  * was interrupted by a signal, and the remaining jiffies otherwise
 329  * if the condition evaluated to true before the timeout elapsed.
 330  */
 331 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
 332 ({                                                                      \
 333         long __ret = timeout;                                           \
 334         if (!(condition))                                               \
 335                 __wait_event_interruptible_timeout(wq, condition, __ret); \
 336         __ret;                                                          \
 337 })
 338
 339 #define __wait_event_hrtimeout(wq, condition, timeout, state)           \
 340 ({                                                                      \
 341         int __ret = 0;                                                  \
 342         DEFINE_WAIT(__wait);                                            \
 343         struct hrtimer_sleeper __t;                                     \
 344                                                                         \
 345         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
 346                               HRTIMER_MODE_REL);                        \
 347         hrtimer_init_sleeper(&__t, current);                            \
 348         if ((timeout).tv64 != KTIME_MAX)                                \
 349                 hrtimer_start_range_ns(&__t.timer, timeout,             \
 350                                        current->timer_slack_ns,         \
 351                                        HRTIMER_MODE_REL);               \
 352                                                                         \
 353         for (;;) {                                                      \
 354                 prepare_to_wait(&wq, &__wait, state);                   \
 355                 if (condition)                                          \
 356                         break;                                          \
 357                 if (state == TASK_INTERRUPTIBLE &&                      \
 358                     signal_pending(current)) {                          \
 359                         __ret = -ERESTARTSYS;                           \
 360                         break;                                          \
 361                 }                                                       \
 362                 if (!__t.task) {                                        \
 363                         __ret = -ETIME;                                 \
 364                         break;                                          \
 365                 }                                                       \
 366                 schedule();                                             \
 367         }                                                               \
 368                                                                         \
 369         hrtimer_cancel(&__t.timer);                                     \
 370         destroy_hrtimer_on_stack(&__t.timer);                           \
 371         finish_wait(&wq, &__wait);                                      \
 372         __ret;                                                          \
 373 })
 374
 375 /**
 376  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
 377  * @wq: the waitqueue to wait on
 378  * @condition: a C expression for the event to wait for
 379  * @timeout: timeout, as a ktime_t
 380  *
 381  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 382  * @condition evaluates to true or a signal is received.
 383  * The @condition is checked each time the waitqueue @wq is woken up.
 384  *
 385  * wake_up() has to be called after changing any variable that could
 386  * change the result of the wait condition.
 387  *
 388  * The function returns 0 if @condition became true, or -ETIME if the timeout
 389  * elapsed.
 390  */
 391 #define wait_event_hrtimeout(wq, condition, timeout)                    \
 392 ({                                                                      \
 393         int __ret = 0;                                                  \
 394         if (!(condition))                                               \
 395                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 396                                                TASK_UNINTERRUPTIBLE);   \
 397         __ret;                                                          \
 398 })
 399
 400 /**
 401  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
 402  * @wq: the waitqueue to wait on
 403  * @condition: a C expression for the event to wait for
 404  * @timeout: timeout, as a ktime_t
 405  *
 406  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 407  * @condition evaluates to true or a signal is received.
 408  * The @condition is checked each time the waitqueue @wq is woken up.
 409  *
 410  * wake_up() has to be called after changing any variable that could
 411  * change the result of the wait condition.
 412  *
 413  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
 414  * interrupted by a signal, or -ETIME if the timeout elapsed.
 415  */
 416 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
 417 ({                                                                      \
 418         long __ret = 0;                                                 \
 419         if (!(condition))                                               \
 420                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 421                                                TASK_INTERRUPTIBLE);     \
 422         __ret;                                                          \
 423 })
 424
 425 #define __wait_event_interruptible_exclusive(wq, condition, ret)        \
 426 do {                                                                    \
 427         DEFINE_WAIT(__wait);                                            \
 428                                                                         \
 429         for (;;) {                                                      \
 430                 prepare_to_wait_exclusive(&wq, &__wait,                 \
 431                                         TASK_INTERRUPTIBLE);            \
 432                 if (condition) {                                        \
 433                         finish_wait(&wq, &__wait);                      \
 434                         break;                                          \
 435                 }                                                       \
 436                 if (!signal_pending(current)) {                         \
 437                         schedule();                                     \
 438                         continue;                                       \
 439                 }                                                       \
 440                 ret = -ERESTARTSYS;                                     \
 441                 abort_exclusive_wait(&wq, &__wait,                      \
 442                                 TASK_INTERRUPTIBLE, NULL);              \
 443                 break;                                                  \
 444         }                                                               \
 445 } while (0)
 446
 447 #define wait_event_interruptible_exclusive(wq, condition)               \
 448 ({                                                                      \
 449         int __ret = 0;                                                  \
 450         if (!(condition))                                               \
 451                 __wait_event_interruptible_exclusive(wq, condition, __ret);\
 452         __ret;                                                          \
 453 })
 454
 455
 456 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
 457 ({                                                                      \
 458         int __ret = 0;                                                  \
 459         DEFINE_WAIT(__wait);                                            \
 460         if (exclusive)                                                  \
 461                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
 462         do {                                                            \
 463                 if (likely(list_empty(&__wait.task_list)))              \
 464                         __add_wait_queue_tail(&(wq), &__wait);          \
 465                 set_current_state(TASK_INTERRUPTIBLE);                  \
 466                 if (signal_pending(current)) {                          \
 467                         __ret = -ERESTARTSYS;                           \
 468                         break;                                          \
 469                 }                                                       \
 470                 if (irq)                                                \
 471                         spin_unlock_irq(&(wq).lock);                    \
 472                 else                                                    \
 473                         spin_unlock(&(wq).lock);                        \
 474                 schedule();                                             \
 475                 if (irq)                                                \
 476                         spin_lock_irq(&(wq).lock);                      \
 477                 else                                                    \
 478                         spin_lock(&(wq).lock);                          \
 479         } while (!(condition));                                         \
 480         __remove_wait_queue(&(wq), &__wait);                            \
 481         __set_current_state(TASK_RUNNING);                              \
 482         __ret;                                                          \
 483 })
 484
 485
 486 /**
 487  * wait_event_interruptible_locked - sleep until a condition gets true
 488  * @wq: the waitqueue to wait on
 489  * @condition: a C expression for the event to wait for
 490  *
 491  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 492  * @condition evaluates to true or a signal is received.
 493  * The @condition is checked each time the waitqueue @wq is woken up.
 494  *
 495  * It must be called with wq.lock being held.  This spinlock is
 496  * unlocked while sleeping but @condition testing is done while lock
 497  * is held and when this macro exits the lock is held.
 498  *
 499  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 500  * functions which must match the way they are locked/unlocked outside
 501  * of this macro.
 502  *
 503  * wake_up_locked() has to be called after changing any variable that could
 504  * change the result of the wait condition.
 505  *
 506  * The function will return -ERESTARTSYS if it was interrupted by a
 507  * signal and 0 if @condition evaluated to true.
 508  */
 509 #define wait_event_interruptible_locked(wq, condition)                  \
 510         ((condition)                                                    \
 511          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
 512
 513 /**
 514  * wait_event_interruptible_locked_irq - sleep until a condition gets true
 515  * @wq: the waitqueue to wait on
 516  * @condition: a C expression for the event to wait for
 517  *
 518  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 519  * @condition evaluates to true or a signal is received.
 520  * The @condition is checked each time the waitqueue @wq is woken up.
 521  *
 522  * It must be called with wq.lock being held.  This spinlock is
 523  * unlocked while sleeping but @condition testing is done while lock
 524  * is held and when this macro exits the lock is held.
 525  *
 526  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 527  * functions which must match the way they are locked/unlocked outside
 528  * of this macro.
 529  *
 530  * wake_up_locked() has to be called after changing any variable that could
 531  * change the result of the wait condition.
 532  *
 533  * The function will return -ERESTARTSYS if it was interrupted by a
 534  * signal and 0 if @condition evaluated to true.
 535  */
 536 #define wait_event_interruptible_locked_irq(wq, condition)              \
 537         ((condition)                                                    \
 538          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
 539
 540 /**
 541  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
 542  * @wq: the waitqueue to wait on
 543  * @condition: a C expression for the event to wait for
 544  *
 545  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 546  * @condition evaluates to true or a signal is received.
 547  * The @condition is checked each time the waitqueue @wq is woken up.
 548  *
 549  * It must be called with wq.lock being held.  This spinlock is
 550  * unlocked while sleeping but @condition testing is done while lock
 551  * is held and when this macro exits the lock is held.
 552  *
 553  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 554  * functions which must match the way they are locked/unlocked outside
 555  * of this macro.
 556  *
 557  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 558  * set thus when other process waits process on the list if this
 559  * process is awaken further processes are not considered.
 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_exclusive_locked(wq, condition)        \
 568         ((condition)                                                    \
 569          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
 570
 571 /**
 572  * wait_event_interruptible_exclusive_locked_irq - sleep 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_irq()/spin_unlock_irq()
 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_irq(wq, condition)    \
 599         ((condition)                                                    \
 600          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
 601
 602
 603
 604 #define __wait_event_killable(wq, condition, ret)                       \
 605 do {                                                                    \
 606         DEFINE_WAIT(__wait);                                            \
 607                                                                         \
 608         for (;;) {                                                      \
 609                 prepare_to_wait(&wq, &__wait, TASK_KILLABLE);           \
 610                 if (condition)                                          \
 611                         break;                                          \
 612                 if (!fatal_signal_pending(current)) {                   \
 613                         schedule();                                     \
 614                         continue;                                       \
 615                 }                                                       \
 616                 ret = -ERESTARTSYS;                                     \
 617                 break;                                                  \
 618         }                                                               \
 619         finish_wait(&wq, &__wait);                                      \
 620 } while (0)
 621
 622 /**
 623  * wait_event_killable - sleep until a condition gets true
 624  * @wq: the waitqueue to wait on
 625  * @condition: a C expression for the event to wait for
 626  *
 627  * The process is put to sleep (TASK_KILLABLE) until the
 628  * @condition evaluates to true or a signal is received.
 629  * The @condition is checked each time the waitqueue @wq is woken up.
 630  *
 631  * wake_up() has to be called after changing any variable that could
 632  * change the result of the wait condition.
 633  *
 634  * The function will return -ERESTARTSYS if it was interrupted by a
 635  * signal and 0 if @condition evaluated to true.
 636  */
 637 #define wait_event_killable(wq, condition)                              \
 638 ({                                                                      \
 639         int __ret = 0;                                                  \
 640         if (!(condition))                                               \
 641                 __wait_event_killable(wq, condition, __ret);            \
 642         __ret;                                                          \
 643 })
 644
 645
 646 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 647 do {                                                                    \
 648         DEFINE_WAIT(__wait);                                            \
 649                                                                         \
 650         for (;;) {                                                      \
 651                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 652                 if (condition)                                          \
 653                         break;                                          \
 654                 spin_unlock_irq(&lock);                                 \
 655                 cmd;                                                    \
 656                 schedule();                                             \
 657                 spin_lock_irq(&lock);                                   \
 658         }                                                               \
 659         finish_wait(&wq, &__wait);                                      \
 660 } while (0)
 661
 662 /**
 663  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
 664  *                           condition is checked under the lock. This
 665  *                           is expected to be called with the lock
 666  *                           taken.
 667  * @wq: the waitqueue to wait on
 668  * @condition: a C expression for the event to wait for
 669  * @lock: a locked spinlock_t, which will be released before cmd
 670  *        and schedule() and reacquired afterwards.
 671  * @cmd: a command which is invoked outside the critical section before
 672  *       sleep
 673  *
 674  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 675  * @condition evaluates to true. The @condition is checked each time
 676  * the waitqueue @wq is woken up.
 677  *
 678  * wake_up() has to be called after changing any variable that could
 679  * change the result of the wait condition.
 680  *
 681  * This is supposed to be called while holding the lock. The lock is
 682  * dropped before invoking the cmd and going to sleep and is reacquired
 683  * afterwards.
 684  */
 685 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
 686 do {                                                                    \
 687         if (condition)                                                  \
 688                 break;                                                  \
 689         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 690 } while (0)
 691
 692 /**
 693  * wait_event_lock_irq - sleep until a condition gets true. The
 694  *                       condition is checked under the lock. This
 695  *                       is expected to be called with the lock
 696  *                       taken.
 697  * @wq: the waitqueue to wait on
 698  * @condition: a C expression for the event to wait for
 699  * @lock: a locked spinlock_t, which will be released before schedule()
 700  *        and reacquired afterwards.
 701  *
 702  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 703  * @condition evaluates to true. The @condition is checked each time
 704  * the waitqueue @wq is woken up.
 705  *
 706  * wake_up() has to be called after changing any variable that could
 707  * change the result of the wait condition.
 708  *
 709  * This is supposed to be called while holding the lock. The lock is
 710  * dropped before going to sleep and is reacquired afterwards.
 711  */
 712 #define wait_event_lock_irq(wq, condition, lock)                        \
 713 do {                                                                    \
 714         if (condition)                                                  \
 715                 break;                                                  \
 716         __wait_event_lock_irq(wq, condition, lock, );                   \
 717 } while (0)
 718
 719
 720 #define __wait_event_interruptible_lock_irq(wq, condition,              \
 721                                             lock, ret, cmd)             \
 722 do {                                                                    \
 723         DEFINE_WAIT(__wait);                                            \
 724                                                                         \
 725         for (;;) {                                                      \
 726                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 727                 if (condition)                                          \
 728                         break;                                          \
 729                 if (signal_pending(current)) {                          \
 730                         ret = -ERESTARTSYS;                             \
 731                         break;                                          \
 732                 }                                                       \
 733                 spin_unlock_irq(&lock);                                 \
 734                 cmd;                                                    \
 735                 schedule();                                             \
 736                 spin_lock_irq(&lock);                                   \
 737         }                                                               \
 738         finish_wait(&wq, &__wait);                                      \
 739 } while (0)
 740
 741 /**
 742  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
 743  *              The condition is checked under the lock. This is expected to
 744  *              be called with the lock taken.
 745  * @wq: the waitqueue to wait on
 746  * @condition: a C expression for the event to wait for
 747  * @lock: a locked spinlock_t, which will be released before cmd and
 748  *        schedule() and reacquired afterwards.
 749  * @cmd: a command which is invoked outside the critical section before
 750  *       sleep
 751  *
 752  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 753  * @condition evaluates to true or a signal is received. The @condition is
 754  * checked each time the waitqueue @wq is woken up.
 755  *
 756  * wake_up() has to be called after changing any variable that could
 757  * change the result of the wait condition.
 758  *
 759  * This is supposed to be called while holding the lock. The lock is
 760  * dropped before invoking the cmd and going to sleep and is reacquired
 761  * afterwards.
 762  *
 763  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 764  * and 0 if @condition evaluated to true.
 765  */
 766 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
 767 ({                                                                      \
 768         int __ret = 0;                                                  \
 769                                                                         \
 770         if (!(condition))                                               \
 771                 __wait_event_interruptible_lock_irq(wq, condition,      \
 772                                                     lock, __ret, cmd);  \
 773         __ret;                                                          \
 774 })
 775
 776 /**
 777  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
 778  *              The condition is checked under the lock. This is expected
 779  *              to be called with the lock taken.
 780  * @wq: the waitqueue to wait on
 781  * @condition: a C expression for the event to wait for
 782  * @lock: a locked spinlock_t, which will be released before schedule()
 783  *        and reacquired afterwards.
 784  *
 785  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 786  * @condition evaluates to true or signal is received. The @condition is
 787  * checked each time the waitqueue @wq is woken up.
 788  *
 789  * wake_up() has to be called after changing any variable that could
 790  * change the result of the wait condition.
 791  *
 792  * This is supposed to be called while holding the lock. The lock is
 793  * dropped before going to sleep and is reacquired afterwards.
 794  *
 795  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 796  * and 0 if @condition evaluated to true.
 797  */
 798 #define wait_event_interruptible_lock_irq(wq, condition, lock)          \
 799 ({                                                                      \
 800         int __ret = 0;                                                  \
 801                                                                         \
 802         if (!(condition))                                               \
 803                 __wait_event_interruptible_lock_irq(wq, condition,      \
 804                                                     lock, __ret, );     \
 805         __ret;                                                          \
 806 })
 807
 808
 809 /*
 810  * These are the old interfaces to sleep waiting for an event.
 811  * They are racy.  DO NOT use them, use the wait_event* interfaces above.
 812  * We plan to remove these interfaces.
 813  */
 814 extern void sleep_on(wait_queue_head_t *q);
 815 extern long sleep_on_timeout(wait_queue_head_t *q,
 816                                       signed long timeout);
 817 extern void interruptible_sleep_on(wait_queue_head_t *q);
 818 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
 819                                            signed long timeout);
 820
 821 /*
 822  * Waitqueues which are removed from the waitqueue_head at wakeup time
 823  */
 824 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
 825 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
 826 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
 827 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
 828                         unsigned int mode, void *key);
 829 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 830 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 831
 832 #define DEFINE_WAIT_FUNC(name, function)                                \
 833         wait_queue_t name = {                                           \
 834                 .private        = current,                              \
 835                 .func           = function,                             \
 836                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
 837         }
 838
 839 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
 840
 841 #define DEFINE_WAIT_BIT(name, word, bit)                                \
 842         struct wait_bit_queue name = {                                  \
 843                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
 844                 .wait   = {                                             \
 845                         .private        = current,                      \
 846                         .func           = wake_bit_function,            \
 847                         .task_list      =                               \
 848                                 LIST_HEAD_INIT((name).wait.task_list),  \
 849                 },                                                      \
 850         }
 851
 852 #define init_wait(wait)                                                 \
 853         do {                                                            \
 854                 (wait)->private = current;                              \
 855                 (wait)->func = autoremove_wake_function;                \
 856                 INIT_LIST_HEAD(&(wait)->task_list);                     \
 857                 (wait)->flags = 0;                                      \
 858         } while (0)
 859
 860 /**
 861  * wait_on_bit - wait for a bit to be cleared
 862  * @word: the word being waited on, a kernel virtual address
 863  * @bit: the bit of the word being waited on
 864  * @action: the function used to sleep, which may take special actions
 865  * @mode: the task state to sleep in
 866  *
 867  * There is a standard hashed waitqueue table for generic use. This
 868  * is the part of the hashtable's accessor API that waits on a bit.
 869  * For instance, if one were to have waiters on a bitflag, one would
 870  * call wait_on_bit() in threads waiting for the bit to clear.
 871  * One uses wait_on_bit() where one is waiting for the bit to clear,
 872  * but has no intention of setting it.
 873  */
 874 static inline int wait_on_bit(void *word, int bit,
 875                                 int (*action)(void *), unsigned mode)
 876 {
 877         if (!test_bit(bit, word))
 878                 return 0;
 879         return out_of_line_wait_on_bit(word, bit, action, mode);
 880 }
 881
 882 /**
 883  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
 884  * @word: the word being waited on, a kernel virtual address
 885  * @bit: the bit of the word being waited on
 886  * @action: the function used to sleep, which may take special actions
 887  * @mode: the task state to sleep in
 888  *
 889  * There is a standard hashed waitqueue table for generic use. This
 890  * is the part of the hashtable's accessor API that waits on a bit
 891  * when one intends to set it, for instance, trying to lock bitflags.
 892  * For instance, if one were to have waiters trying to set bitflag
 893  * and waiting for it to clear before setting it, one would call
 894  * wait_on_bit() in threads waiting to be able to set the bit.
 895  * One uses wait_on_bit_lock() where one is waiting for the bit to
 896  * clear with the intention of setting it, and when done, clearing it.
 897  */
 898 static inline int wait_on_bit_lock(void *word, int bit,
 899                                 int (*action)(void *), unsigned mode)
 900 {
 901         if (!test_and_set_bit(bit, word))
 902                 return 0;
 903         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
 904 }
 905
 906 /**
 907  * wait_on_atomic_t - Wait for an atomic_t to become 0
 908  * @val: The atomic value being waited on, a kernel virtual address
 909  * @action: the function used to sleep, which may take special actions
 910  * @mode: the task state to sleep in
 911  *
 912  * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
 913  * the purpose of getting a waitqueue, but we set the key to a bit number
 914  * outside of the target 'word'.
 915  */
 916 static inline
 917 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
 918 {
 919         if (atomic_read(val) == 0)
 920                 return 0;
 921         return out_of_line_wait_on_atomic_t(val, action, mode);
 922 }
 923
 924 #endif