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 };
  27
  28 struct wait_bit_queue {
  29         struct wait_bit_key key;
  30         wait_queue_t wait;
  31 };
  32
  33 struct __wait_queue_head {
  34         spinlock_t lock;
  35         struct list_head task_list;
  36 };
  37 typedef struct __wait_queue_head wait_queue_head_t;
  38
  39 struct task_struct;
  40
  41 /*
  42  * Macros for declaration and initialisaton of the datatypes
  43  */
  44
  45 #define __WAITQUEUE_INITIALIZER(name, tsk) {                            \
  46         .private        = tsk,                                          \
  47         .func           = default_wake_function,                        \
  48         .task_list      = { NULL, NULL } }
  49
  50 #define DECLARE_WAITQUEUE(name, tsk)                                    \
  51         wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
  52
  53 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                           \
  54         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),              \
  55         .task_list      = { &(name).task_list, &(name).task_list } }
  56
  57 #define DECLARE_WAIT_QUEUE_HEAD(name) \
  58         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
  59
  60 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)                           \
  61         { .flags = word, .bit_nr = bit, }
  62
  63 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
  64
  65 #define init_waitqueue_head(q)                          \
  66         do {                                            \
  67                 static struct lock_class_key __key;     \
  68                                                         \
  69                 __init_waitqueue_head((q), #q, &__key); \
  70         } while (0)
  71
  72 #ifdef CONFIG_LOCKDEP
  73 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
  74         ({ init_waitqueue_head(&name); name; })
  75 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
  76         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
  77 #else
  78 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
  79 #endif
  80
  81 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
  82 {
  83         q->flags = 0;
  84         q->private = p;
  85         q->func = default_wake_function;
  86 }
  87
  88 static inline void init_waitqueue_func_entry(wait_queue_t *q,
  89                                         wait_queue_func_t func)
  90 {
  91         q->flags = 0;
  92         q->private = NULL;
  93         q->func = func;
  94 }
  95
  96 static inline int waitqueue_active(wait_queue_head_t *q)
  97 {
  98         return !list_empty(&q->task_list);
  99 }
 100
 101 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 102 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
 103 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 104
 105 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
 106 {
 107         list_add(&new->task_list, &head->task_list);
 108 }
 109
 110 /*
 111  * Used for wake-one threads:
 112  */
 113 static inline void __add_wait_queue_exclusive(wait_queue_head_t *q,
 114                                               wait_queue_t *wait)
 115 {
 116         wait->flags |= WQ_FLAG_EXCLUSIVE;
 117         __add_wait_queue(q, wait);
 118 }
 119
 120 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
 121                                          wait_queue_t *new)
 122 {
 123         list_add_tail(&new->task_list, &head->task_list);
 124 }
 125
 126 static inline void __add_wait_queue_tail_exclusive(wait_queue_head_t *q,
 127                                               wait_queue_t *wait)
 128 {
 129         wait->flags |= WQ_FLAG_EXCLUSIVE;
 130         __add_wait_queue_tail(q, wait);
 131 }
 132
 133 static inline void __remove_wait_queue(wait_queue_head_t *head,
 134                                                         wait_queue_t *old)
 135 {
 136         list_del(&old->task_list);
 137 }
 138
 139 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 140 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
 141 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr,
 142                         void *key);
 143 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
 144 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
 145 void __wake_up_bit(wait_queue_head_t *, void *, int);
 146 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
 147 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
 148 void wake_up_bit(void *, int);
 149 int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned);
 150 int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned);
 151 wait_queue_head_t *bit_waitqueue(void *, int);
 152
 153 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
 154 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
 155 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
 156 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL, 1)
 157 #define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)
 158
 159 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 160 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
 161 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
 162 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
 163
 164 /*
 165  * Wakeup macros to be used to report events to the targets.
 166  */
 167 #define wake_up_poll(x, m)                              \
 168         __wake_up(x, TASK_NORMAL, 1, (void *) (m))
 169 #define wake_up_locked_poll(x, m)                               \
 170         __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
 171 #define wake_up_interruptible_poll(x, m)                        \
 172         __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
 173 #define wake_up_interruptible_sync_poll(x, m)                           \
 174         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
 175
 176 #define __wait_event(wq, condition)                                     \
 177 do {                                                                    \
 178         DEFINE_WAIT(__wait);                                            \
 179                                                                         \
 180         for (;;) {                                                      \
 181                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 182                 if (condition)                                          \
 183                         break;                                          \
 184                 schedule();                                             \
 185         }                                                               \
 186         finish_wait(&wq, &__wait);                                      \
 187 } while (0)
 188
 189 /**
 190  * wait_event - sleep until a condition gets true
 191  * @wq: the waitqueue to wait on
 192  * @condition: a C expression for the event to wait for
 193  *
 194  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 195  * @condition evaluates to true. The @condition is checked each time
 196  * the waitqueue @wq is woken up.
 197  *
 198  * wake_up() has to be called after changing any variable that could
 199  * change the result of the wait condition.
 200  */
 201 #define wait_event(wq, condition)                                       \
 202 do {                                                                    \
 203         if (condition)                                                  \
 204                 break;                                                  \
 205         __wait_event(wq, condition);                                    \
 206 } while (0)
 207
 208 #define __wait_event_timeout(wq, condition, ret)                        \
 209 do {                                                                    \
 210         DEFINE_WAIT(__wait);                                            \
 211                                                                         \
 212         for (;;) {                                                      \
 213                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 214                 if (condition)                                          \
 215                         break;                                          \
 216                 ret = schedule_timeout(ret);                            \
 217                 if (!ret)                                               \
 218                         break;                                          \
 219         }                                                               \
 220         if (!ret && (condition))                                        \
 221                 ret = 1;                                                \
 222         finish_wait(&wq, &__wait);                                      \
 223 } while (0)
 224
 225 /**
 226  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 227  * @wq: the waitqueue to wait on
 228  * @condition: a C expression for the event to wait for
 229  * @timeout: timeout, in jiffies
 230  *
 231  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 232  * @condition evaluates to true. The @condition is checked each time
 233  * the waitqueue @wq is woken up.
 234  *
 235  * wake_up() has to be called after changing any variable that could
 236  * change the result of the wait condition.
 237  *
 238  * The function returns 0 if the @timeout elapsed, or the remaining
 239  * jiffies (at least 1) if the @condition evaluated to %true before
 240  * the @timeout elapsed.
 241  */
 242 #define wait_event_timeout(wq, condition, timeout)                      \
 243 ({                                                                      \
 244         long __ret = timeout;                                           \
 245         if (!(condition))                                               \
 246                 __wait_event_timeout(wq, condition, __ret);             \
 247         __ret;                                                          \
 248 })
 249
 250 #define __wait_event_interruptible(wq, condition, ret)                  \
 251 do {                                                                    \
 252         DEFINE_WAIT(__wait);                                            \
 253                                                                         \
 254         for (;;) {                                                      \
 255                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 256                 if (condition)                                          \
 257                         break;                                          \
 258                 if (!signal_pending(current)) {                         \
 259                         schedule();                                     \
 260                         continue;                                       \
 261                 }                                                       \
 262                 ret = -ERESTARTSYS;                                     \
 263                 break;                                                  \
 264         }                                                               \
 265         finish_wait(&wq, &__wait);                                      \
 266 } while (0)
 267
 268 /**
 269  * wait_event_interruptible - sleep until a condition gets true
 270  * @wq: the waitqueue to wait on
 271  * @condition: a C expression for the event to wait for
 272  *
 273  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 274  * @condition evaluates to true or a signal is received.
 275  * The @condition is checked each time the waitqueue @wq is woken up.
 276  *
 277  * wake_up() has to be called after changing any variable that could
 278  * change the result of the wait condition.
 279  *
 280  * The function will return -ERESTARTSYS if it was interrupted by a
 281  * signal and 0 if @condition evaluated to true.
 282  */
 283 #define wait_event_interruptible(wq, condition)                         \
 284 ({                                                                      \
 285         int __ret = 0;                                                  \
 286         if (!(condition))                                               \
 287                 __wait_event_interruptible(wq, condition, __ret);       \
 288         __ret;                                                          \
 289 })
 290
 291 #define __wait_event_interruptible_timeout(wq, condition, ret)          \
 292 do {                                                                    \
 293         DEFINE_WAIT(__wait);                                            \
 294                                                                         \
 295         for (;;) {                                                      \
 296                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 297                 if (condition)                                          \
 298                         break;                                          \
 299                 if (!signal_pending(current)) {                         \
 300                         ret = schedule_timeout(ret);                    \
 301                         if (!ret)                                       \
 302                                 break;                                  \
 303                         continue;                                       \
 304                 }                                                       \
 305                 ret = -ERESTARTSYS;                                     \
 306                 break;                                                  \
 307         }                                                               \
 308         if (!ret && (condition))                                        \
 309                 ret = 1;                                                \
 310         finish_wait(&wq, &__wait);                                      \
 311 } while (0)
 312
 313 /**
 314  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 315  * @wq: the waitqueue to wait on
 316  * @condition: a C expression for the event to wait for
 317  * @timeout: timeout, in jiffies
 318  *
 319  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 320  * @condition evaluates to true or a signal is received.
 321  * The @condition is checked each time the waitqueue @wq is woken up.
 322  *
 323  * wake_up() has to be called after changing any variable that could
 324  * change the result of the wait condition.
 325  *
 326  * Returns:
 327  * 0 if the @timeout elapsed, -%ERESTARTSYS if it was interrupted by
 328  * a signal, or the remaining jiffies (at least 1) if the @condition
 329  * 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 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
 809                                                     lock, ret)          \
 810 do {                                                                    \
 811         DEFINE_WAIT(__wait);                                            \
 812                                                                         \
 813         for (;;) {                                                      \
 814                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 815                 if (condition)                                          \
 816                         break;                                          \
 817                 if (signal_pending(current)) {                          \
 818                         ret = -ERESTARTSYS;                             \
 819                         break;                                          \
 820                 }                                                       \
 821                 spin_unlock_irq(&lock);                                 \
 822                 ret = schedule_timeout(ret);                            \
 823                 spin_lock_irq(&lock);                                   \
 824                 if (!ret)                                               \
 825                         break;                                          \
 826         }                                                               \
 827         finish_wait(&wq, &__wait);                                      \
 828 } while (0)
 829
 830 /**
 831  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets true or a timeout elapses.
 832  *              The condition is checked under the lock. This is expected
 833  *              to be called with the lock taken.
 834  * @wq: the waitqueue to wait on
 835  * @condition: a C expression for the event to wait for
 836  * @lock: a locked spinlock_t, which will be released before schedule()
 837  *        and reacquired afterwards.
 838  * @timeout: timeout, in jiffies
 839  *
 840  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 841  * @condition evaluates to true or signal is received. The @condition is
 842  * checked each time the waitqueue @wq is woken up.
 843  *
 844  * wake_up() has to be called after changing any variable that could
 845  * change the result of the wait condition.
 846  *
 847  * This is supposed to be called while holding the lock. The lock is
 848  * dropped before going to sleep and is reacquired afterwards.
 849  *
 850  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
 851  * was interrupted by a signal, and the remaining jiffies otherwise
 852  * if the condition evaluated to true before the timeout elapsed.
 853  */
 854 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
 855                                                   timeout)              \
 856 ({                                                                      \
 857         int __ret = timeout;                                            \
 858                                                                         \
 859         if (!(condition))                                               \
 860                 __wait_event_interruptible_lock_irq_timeout(            \
 861                                         wq, condition, lock, __ret);    \
 862         __ret;                                                          \
 863 })
 864
 865
 866 /*
 867  * These are the old interfaces to sleep waiting for an event.
 868  * They are racy.  DO NOT use them, use the wait_event* interfaces above.
 869  * We plan to remove these interfaces.
 870  */
 871 extern void sleep_on(wait_queue_head_t *q);
 872 extern long sleep_on_timeout(wait_queue_head_t *q,
 873                                       signed long timeout);
 874 extern void interruptible_sleep_on(wait_queue_head_t *q);
 875 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
 876                                            signed long timeout);
 877
 878 /*
 879  * Waitqueues which are removed from the waitqueue_head at wakeup time
 880  */
 881 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
 882 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
 883 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
 884 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
 885                         unsigned int mode, void *key);
 886 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 887 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 888
 889 #define DEFINE_WAIT_FUNC(name, function)                                \
 890         wait_queue_t name = {                                           \
 891                 .private        = current,                              \
 892                 .func           = function,                             \
 893                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
 894         }
 895
 896 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
 897
 898 #define DEFINE_WAIT_BIT(name, word, bit)                                \
 899         struct wait_bit_queue name = {                                  \
 900                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
 901                 .wait   = {                                             \
 902                         .private        = current,                      \
 903                         .func           = wake_bit_function,            \
 904                         .task_list      =                               \
 905                                 LIST_HEAD_INIT((name).wait.task_list),  \
 906                 },                                                      \
 907         }
 908
 909 #define init_wait(wait)                                                 \
 910         do {                                                            \
 911                 (wait)->private = current;                              \
 912                 (wait)->func = autoremove_wake_function;                \
 913                 INIT_LIST_HEAD(&(wait)->task_list);                     \
 914                 (wait)->flags = 0;                                      \
 915         } while (0)
 916
 917 /**
 918  * wait_on_bit - wait for a bit to be cleared
 919  * @word: the word being waited on, a kernel virtual address
 920  * @bit: the bit of the word being waited on
 921  * @action: the function used to sleep, which may take special actions
 922  * @mode: the task state to sleep in
 923  *
 924  * There is a standard hashed waitqueue table for generic use. This
 925  * is the part of the hashtable's accessor API that waits on a bit.
 926  * For instance, if one were to have waiters on a bitflag, one would
 927  * call wait_on_bit() in threads waiting for the bit to clear.
 928  * One uses wait_on_bit() where one is waiting for the bit to clear,
 929  * but has no intention of setting it.
 930  */
 931 static inline int wait_on_bit(void *word, int bit,
 932                                 int (*action)(void *), unsigned mode)
 933 {
 934         if (!test_bit(bit, word))
 935                 return 0;
 936         return out_of_line_wait_on_bit(word, bit, action, mode);
 937 }
 938
 939 /**
 940  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
 941  * @word: the word being waited on, a kernel virtual address
 942  * @bit: the bit of the word being waited on
 943  * @action: the function used to sleep, which may take special actions
 944  * @mode: the task state to sleep in
 945  *
 946  * There is a standard hashed waitqueue table for generic use. This
 947  * is the part of the hashtable's accessor API that waits on a bit
 948  * when one intends to set it, for instance, trying to lock bitflags.
 949  * For instance, if one were to have waiters trying to set bitflag
 950  * and waiting for it to clear before setting it, one would call
 951  * wait_on_bit() in threads waiting to be able to set the bit.
 952  * One uses wait_on_bit_lock() where one is waiting for the bit to
 953  * clear with the intention of setting it, and when done, clearing it.
 954  */
 955 static inline int wait_on_bit_lock(void *word, int bit,
 956                                 int (*action)(void *), unsigned mode)
 957 {
 958         if (!test_and_set_bit(bit, word))
 959                 return 0;
 960         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
 961 }
 962
 963 #endif