include/linux/wait.h

   1 #ifndef _LINUX_WAIT_H
   2 #define _LINUX_WAIT_H
   3 /*
   4  * Linux wait queue related types and methods
   5  */
   6 #include <linux/list.h>
   7 #include <linux/stddef.h>
   8 #include <linux/spinlock.h>
   9 #include <asm/current.h>
  10 #include <uapi/linux/wait.h>
  11
  12 typedef struct __wait_queue wait_queue_t;
  13 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key);
  14 int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, void *key);
  15
  16 struct __wait_queue {
  17         unsigned int            flags;
  18 #define WQ_FLAG_EXCLUSIVE       0x01
  19         void                    *private;
  20         wait_queue_func_t       func;
  21         struct list_head        task_list;
  22 };
  23
  24 struct wait_bit_key {
  25         void                    *flags;
  26         int                     bit_nr;
  27 #define WAIT_ATOMIC_T_BIT_NR    -1
  28         unsigned long           private;
  29 };
  30
  31 struct wait_bit_queue {
  32         struct wait_bit_key     key;
  33         wait_queue_t            wait;
  34 };
  35
  36 struct __wait_queue_head {
  37         spinlock_t              lock;
  38         struct list_head        task_list;
  39 };
  40 typedef struct __wait_queue_head wait_queue_head_t;
  41
  42 struct task_struct;
  43
  44 /*
  45  * Macros for declaration and initialisaton of the datatypes
  46  */
  47
  48 #define __WAITQUEUE_INITIALIZER(name, tsk) {                            \
  49         .private        = tsk,                                          \
  50         .func           = default_wake_function,                        \
  51         .task_list      = { NULL, NULL } }
  52
  53 #define DECLARE_WAITQUEUE(name, tsk)                                    \
  54         wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
  55
  56 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                           \
  57         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),              \
  58         .task_list      = { &(name).task_list, &(name).task_list } }
  59
  60 #define DECLARE_WAIT_QUEUE_HEAD(name) \
  61         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
  62
  63 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)                           \
  64         { .flags = word, .bit_nr = bit, }
  65
  66 #define __WAIT_ATOMIC_T_KEY_INITIALIZER(p)                              \
  67         { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }
  68
  69 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
  70
  71 #define init_waitqueue_head(q)                          \
  72         do {                                            \
  73                 static struct lock_class_key __key;     \
  74                                                         \
  75                 __init_waitqueue_head((q), #q, &__key); \
  76         } while (0)
  77
  78 #ifdef CONFIG_LOCKDEP
  79 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
  80         ({ init_waitqueue_head(&name); name; })
  81 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
  82         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
  83 #else
  84 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
  85 #endif
  86
  87 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
  88 {
  89         q->flags        = 0;
  90         q->private      = p;
  91         q->func         = default_wake_function;
  92 }
  93
  94 static inline void
  95 init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func)
  96 {
  97         q->flags        = 0;
  98         q->private      = NULL;
  99         q->func         = func;
 100 }
 101
 102 static inline int waitqueue_active(wait_queue_head_t *q)
 103 {
 104         return !list_empty(&q->task_list);
 105 }
 106
 107 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 108 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
 109 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 110
 111 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
 112 {
 113         list_add(&new->task_list, &head->task_list);
 114 }
 115
 116 /*
 117  * Used for wake-one threads:
 118  */
 119 static inline void
 120 __add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
 121 {
 122         wait->flags |= WQ_FLAG_EXCLUSIVE;
 123         __add_wait_queue(q, wait);
 124 }
 125
 126 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
 127                                          wait_queue_t *new)
 128 {
 129         list_add_tail(&new->task_list, &head->task_list);
 130 }
 131
 132 static inline void
 133 __add_wait_queue_tail_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
 134 {
 135         wait->flags |= WQ_FLAG_EXCLUSIVE;
 136         __add_wait_queue_tail(q, wait);
 137 }
 138
 139 static inline void
 140 __remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old)
 141 {
 142         list_del(&old->task_list);
 143 }
 144
 145 typedef int wait_bit_action_f(struct wait_bit_key *);
 146 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 147 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
 148 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 149 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
 150 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
 151 void __wake_up_bit(wait_queue_head_t *, void *, int);
 152 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
 153 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
 154 void wake_up_bit(void *, int);
 155 void wake_up_atomic_t(atomic_t *);
 156 int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned);
 157 int out_of_line_wait_on_bit_lock(void *, int, wait_bit_action_f *, unsigned);
 158 int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned);
 159 wait_queue_head_t *bit_waitqueue(void *, int);
 160
 161 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
 162 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
 163 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
 164 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL, 1)
 165 #define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)
 166
 167 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 168 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
 169 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
 170 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
 171
 172 /*
 173  * Wakeup macros to be used to report events to the targets.
 174  */
 175 #define wake_up_poll(x, m)                                              \
 176         __wake_up(x, TASK_NORMAL, 1, (void *) (m))
 177 #define wake_up_locked_poll(x, m)                                       \
 178         __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
 179 #define wake_up_interruptible_poll(x, m)                                \
 180         __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
 181 #define wake_up_interruptible_sync_poll(x, m)                           \
 182         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
 183
 184 #define ___wait_cond_timeout(condition)                                 \
 185 ({                                                                      \
 186         bool __cond = (condition);                                      \
 187         if (__cond && !__ret)                                           \
 188                 __ret = 1;                                              \
 189         __cond || !__ret;                                               \
 190 })
 191
 192 #define ___wait_is_interruptible(state)                                 \
 193         (!__builtin_constant_p(state) ||                                \
 194                 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE)  \
 195
 196 /*
 197  * The below macro ___wait_event() has an explicit shadow of the __ret
 198  * variable when used from the wait_event_*() macros.
 199  *
 200  * This is so that both can use the ___wait_cond_timeout() construct
 201  * to wrap the condition.
 202  *
 203  * The type inconsistency of the wait_event_*() __ret variable is also
 204  * on purpose; we use long where we can return timeout values and int
 205  * otherwise.
 206  */
 207
 208 #define ___wait_event(wq, condition, state, exclusive, ret, cmd)        \
 209 ({                                                                      \
 210         __label__ __out;                                                \
 211         wait_queue_t __wait;                                            \
 212         long __ret = ret;       /* explicit shadow */                   \
 213                                                                         \
 214         INIT_LIST_HEAD(&__wait.task_list);                              \
 215         if (exclusive)                                                  \
 216                 __wait.flags = WQ_FLAG_EXCLUSIVE;                       \
 217         else                                                            \
 218                 __wait.flags = 0;                                       \
 219                                                                         \
 220         for (;;) {                                                      \
 221                 long __int = prepare_to_wait_event(&wq, &__wait, state);\
 222                                                                         \
 223                 if (condition)                                          \
 224                         break;                                          \
 225                                                                         \
 226                 if (___wait_is_interruptible(state) && __int) {         \
 227                         __ret = __int;                                  \
 228                         if (exclusive) {                                \
 229                                 abort_exclusive_wait(&wq, &__wait,      \
 230                                                      state, NULL);      \
 231                                 goto __out;                             \
 232                         }                                               \
 233                         break;                                          \
 234                 }                                                       \
 235                                                                         \
 236                 cmd;                                                    \
 237         }                                                               \
 238         finish_wait(&wq, &__wait);                                      \
 239 __out:  __ret;                                                          \
 240 })
 241
 242 #define __wait_event(wq, condition)                                     \
 243         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 244                             schedule())
 245
 246 /**
 247  * wait_event - sleep until a condition gets true
 248  * @wq: the waitqueue to wait on
 249  * @condition: a C expression for the event to wait for
 250  *
 251  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 252  * @condition evaluates to true. The @condition is checked each time
 253  * the waitqueue @wq is woken up.
 254  *
 255  * wake_up() has to be called after changing any variable that could
 256  * change the result of the wait condition.
 257  */
 258 #define wait_event(wq, condition)                                       \
 259 do {                                                                    \
 260         if (condition)                                                  \
 261                 break;                                                  \
 262         __wait_event(wq, condition);                                    \
 263 } while (0)
 264
 265 #define __wait_event_timeout(wq, condition, timeout)                    \
 266         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 267                       TASK_UNINTERRUPTIBLE, 0, timeout,                 \
 268                       __ret = schedule_timeout(__ret))
 269
 270 /**
 271  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 272  * @wq: the waitqueue to wait on
 273  * @condition: a C expression for the event to wait for
 274  * @timeout: timeout, in jiffies
 275  *
 276  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 277  * @condition evaluates to true. The @condition is checked each time
 278  * 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  * Returns:
 284  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 285  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 286  * or the remaining jiffies (at least 1) if the @condition evaluated
 287  * to %true before the @timeout elapsed.
 288  */
 289 #define wait_event_timeout(wq, condition, timeout)                      \
 290 ({                                                                      \
 291         long __ret = timeout;                                           \
 292         if (!___wait_cond_timeout(condition))                           \
 293                 __ret = __wait_event_timeout(wq, condition, timeout);   \
 294         __ret;                                                          \
 295 })
 296
 297 #define __wait_event_cmd(wq, condition, cmd1, cmd2)                     \
 298         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 299                             cmd1; schedule(); cmd2)
 300
 301 /**
 302  * wait_event_cmd - sleep until a condition gets true
 303  * @wq: the waitqueue to wait on
 304  * @condition: a C expression for the event to wait for
 305  * @cmd1: the command will be executed before sleep
 306  * @cmd2: the command will be executed after sleep
 307  *
 308  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 309  * @condition evaluates to true. The @condition is checked each time
 310  * the waitqueue @wq is woken up.
 311  *
 312  * wake_up() has to be called after changing any variable that could
 313  * change the result of the wait condition.
 314  */
 315 #define wait_event_cmd(wq, condition, cmd1, cmd2)                       \
 316 do {                                                                    \
 317         if (condition)                                                  \
 318                 break;                                                  \
 319         __wait_event_cmd(wq, condition, cmd1, cmd2);                    \
 320 } while (0)
 321
 322 #define __wait_event_interruptible(wq, condition)                       \
 323         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
 324                       schedule())
 325
 326 /**
 327  * wait_event_interruptible - sleep until a condition gets true
 328  * @wq: the waitqueue to wait on
 329  * @condition: a C expression for the event to wait for
 330  *
 331  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 332  * @condition evaluates to true or a signal is received.
 333  * The @condition is checked each time the waitqueue @wq is woken up.
 334  *
 335  * wake_up() has to be called after changing any variable that could
 336  * change the result of the wait condition.
 337  *
 338  * The function will return -ERESTARTSYS if it was interrupted by a
 339  * signal and 0 if @condition evaluated to true.
 340  */
 341 #define wait_event_interruptible(wq, condition)                         \
 342 ({                                                                      \
 343         int __ret = 0;                                                  \
 344         if (!(condition))                                               \
 345                 __ret = __wait_event_interruptible(wq, condition);      \
 346         __ret;                                                          \
 347 })
 348
 349 #define __wait_event_interruptible_timeout(wq, condition, timeout)      \
 350         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 351                       TASK_INTERRUPTIBLE, 0, timeout,                   \
 352                       __ret = schedule_timeout(__ret))
 353
 354 /**
 355  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 356  * @wq: the waitqueue to wait on
 357  * @condition: a C expression for the event to wait for
 358  * @timeout: timeout, in jiffies
 359  *
 360  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 361  * @condition evaluates to true or a signal is received.
 362  * The @condition is checked each time the waitqueue @wq is woken up.
 363  *
 364  * wake_up() has to be called after changing any variable that could
 365  * change the result of the wait condition.
 366  *
 367  * Returns:
 368  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 369  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 370  * the remaining jiffies (at least 1) if the @condition evaluated
 371  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
 372  * interrupted by a signal.
 373  */
 374 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
 375 ({                                                                      \
 376         long __ret = timeout;                                           \
 377         if (!___wait_cond_timeout(condition))                           \
 378                 __ret = __wait_event_interruptible_timeout(wq,          \
 379                                                 condition, timeout);    \
 380         __ret;                                                          \
 381 })
 382
 383 #define __wait_event_hrtimeout(wq, condition, timeout, state)           \
 384 ({                                                                      \
 385         int __ret = 0;                                                  \
 386         struct hrtimer_sleeper __t;                                     \
 387                                                                         \
 388         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
 389                               HRTIMER_MODE_REL);                        \
 390         hrtimer_init_sleeper(&__t, current);                            \
 391         if ((timeout).tv64 != KTIME_MAX)                                \
 392                 hrtimer_start_range_ns(&__t.timer, timeout,             \
 393                                        current->timer_slack_ns,         \
 394                                        HRTIMER_MODE_REL);               \
 395                                                                         \
 396         __ret = ___wait_event(wq, condition, state, 0, 0,               \
 397                 if (!__t.task) {                                        \
 398                         __ret = -ETIME;                                 \
 399                         break;                                          \
 400                 }                                                       \
 401                 schedule());                                            \
 402                                                                         \
 403         hrtimer_cancel(&__t.timer);                                     \
 404         destroy_hrtimer_on_stack(&__t.timer);                           \
 405         __ret;                                                          \
 406 })
 407
 408 /**
 409  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
 410  * @wq: the waitqueue to wait on
 411  * @condition: a C expression for the event to wait for
 412  * @timeout: timeout, as a ktime_t
 413  *
 414  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 415  * @condition evaluates to true or a signal is received.
 416  * The @condition is checked each time the waitqueue @wq is woken up.
 417  *
 418  * wake_up() has to be called after changing any variable that could
 419  * change the result of the wait condition.
 420  *
 421  * The function returns 0 if @condition became true, or -ETIME if the timeout
 422  * elapsed.
 423  */
 424 #define wait_event_hrtimeout(wq, condition, timeout)                    \
 425 ({                                                                      \
 426         int __ret = 0;                                                  \
 427         if (!(condition))                                               \
 428                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 429                                                TASK_UNINTERRUPTIBLE);   \
 430         __ret;                                                          \
 431 })
 432
 433 /**
 434  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
 435  * @wq: the waitqueue to wait on
 436  * @condition: a C expression for the event to wait for
 437  * @timeout: timeout, as a ktime_t
 438  *
 439  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 440  * @condition evaluates to true or a signal is received.
 441  * The @condition is checked each time the waitqueue @wq is woken up.
 442  *
 443  * wake_up() has to be called after changing any variable that could
 444  * change the result of the wait condition.
 445  *
 446  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
 447  * interrupted by a signal, or -ETIME if the timeout elapsed.
 448  */
 449 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
 450 ({                                                                      \
 451         long __ret = 0;                                                 \
 452         if (!(condition))                                               \
 453                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 454                                                TASK_INTERRUPTIBLE);     \
 455         __ret;                                                          \
 456 })
 457
 458 #define __wait_event_interruptible_exclusive(wq, condition)             \
 459         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
 460                       schedule())
 461
 462 #define wait_event_interruptible_exclusive(wq, condition)               \
 463 ({                                                                      \
 464         int __ret = 0;                                                  \
 465         if (!(condition))                                               \
 466                 __ret = __wait_event_interruptible_exclusive(wq, condition);\
 467         __ret;                                                          \
 468 })
 469
 470
 471 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
 472 ({                                                                      \
 473         int __ret = 0;                                                  \
 474         DEFINE_WAIT(__wait);                                            \
 475         if (exclusive)                                                  \
 476                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
 477         do {                                                            \
 478                 if (likely(list_empty(&__wait.task_list)))              \
 479                         __add_wait_queue_tail(&(wq), &__wait);          \
 480                 set_current_state(TASK_INTERRUPTIBLE);                  \
 481                 if (signal_pending(current)) {                          \
 482                         __ret = -ERESTARTSYS;                           \
 483                         break;                                          \
 484                 }                                                       \
 485                 if (irq)                                                \
 486                         spin_unlock_irq(&(wq).lock);                    \
 487                 else                                                    \
 488                         spin_unlock(&(wq).lock);                        \
 489                 schedule();                                             \
 490                 if (irq)                                                \
 491                         spin_lock_irq(&(wq).lock);                      \
 492                 else                                                    \
 493                         spin_lock(&(wq).lock);                          \
 494         } while (!(condition));                                         \
 495         __remove_wait_queue(&(wq), &__wait);                            \
 496         __set_current_state(TASK_RUNNING);                              \
 497         __ret;                                                          \
 498 })
 499
 500
 501 /**
 502  * wait_event_interruptible_locked - sleep until a condition gets true
 503  * @wq: the waitqueue to wait on
 504  * @condition: a C expression for the event to wait for
 505  *
 506  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 507  * @condition evaluates to true or a signal is received.
 508  * The @condition is checked each time the waitqueue @wq is woken up.
 509  *
 510  * It must be called with wq.lock being held.  This spinlock is
 511  * unlocked while sleeping but @condition testing is done while lock
 512  * is held and when this macro exits the lock is held.
 513  *
 514  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 515  * functions which must match the way they are locked/unlocked outside
 516  * of this macro.
 517  *
 518  * wake_up_locked() has to be called after changing any variable that could
 519  * change the result of the wait condition.
 520  *
 521  * The function will return -ERESTARTSYS if it was interrupted by a
 522  * signal and 0 if @condition evaluated to true.
 523  */
 524 #define wait_event_interruptible_locked(wq, condition)                  \
 525         ((condition)                                                    \
 526          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
 527
 528 /**
 529  * wait_event_interruptible_locked_irq - sleep until a condition gets true
 530  * @wq: the waitqueue to wait on
 531  * @condition: a C expression for the event to wait for
 532  *
 533  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 534  * @condition evaluates to true or a signal is received.
 535  * The @condition is checked each time the waitqueue @wq is woken up.
 536  *
 537  * It must be called with wq.lock being held.  This spinlock is
 538  * unlocked while sleeping but @condition testing is done while lock
 539  * is held and when this macro exits the lock is held.
 540  *
 541  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 542  * functions which must match the way they are locked/unlocked outside
 543  * of this macro.
 544  *
 545  * wake_up_locked() has to be called after changing any variable that could
 546  * change the result of the wait condition.
 547  *
 548  * The function will return -ERESTARTSYS if it was interrupted by a
 549  * signal and 0 if @condition evaluated to true.
 550  */
 551 #define wait_event_interruptible_locked_irq(wq, condition)              \
 552         ((condition)                                                    \
 553          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
 554
 555 /**
 556  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
 557  * @wq: the waitqueue to wait on
 558  * @condition: a C expression for the event to wait for
 559  *
 560  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 561  * @condition evaluates to true or a signal is received.
 562  * The @condition is checked each time the waitqueue @wq is woken up.
 563  *
 564  * It must be called with wq.lock being held.  This spinlock is
 565  * unlocked while sleeping but @condition testing is done while lock
 566  * is held and when this macro exits the lock is held.
 567  *
 568  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 569  * functions which must match the way they are locked/unlocked outside
 570  * of this macro.
 571  *
 572  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 573  * set thus when other process waits process on the list if this
 574  * process is awaken further processes are not considered.
 575  *
 576  * wake_up_locked() has to be called after changing any variable that could
 577  * change the result of the wait condition.
 578  *
 579  * The function will return -ERESTARTSYS if it was interrupted by a
 580  * signal and 0 if @condition evaluated to true.
 581  */
 582 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
 583         ((condition)                                                    \
 584          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
 585
 586 /**
 587  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
 588  * @wq: the waitqueue to wait on
 589  * @condition: a C expression for the event to wait for
 590  *
 591  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 592  * @condition evaluates to true or a signal is received.
 593  * The @condition is checked each time the waitqueue @wq is woken up.
 594  *
 595  * It must be called with wq.lock being held.  This spinlock is
 596  * unlocked while sleeping but @condition testing is done while lock
 597  * is held and when this macro exits the lock is held.
 598  *
 599  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 600  * functions which must match the way they are locked/unlocked outside
 601  * of this macro.
 602  *
 603  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 604  * set thus when other process waits process on the list if this
 605  * process is awaken further processes are not considered.
 606  *
 607  * wake_up_locked() has to be called after changing any variable that could
 608  * change the result of the wait condition.
 609  *
 610  * The function will return -ERESTARTSYS if it was interrupted by a
 611  * signal and 0 if @condition evaluated to true.
 612  */
 613 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
 614         ((condition)                                                    \
 615          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
 616
 617
 618 #define __wait_event_killable(wq, condition)                            \
 619         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
 620
 621 /**
 622  * wait_event_killable - sleep until a condition gets true
 623  * @wq: the waitqueue to wait on
 624  * @condition: a C expression for the event to wait for
 625  *
 626  * The process is put to sleep (TASK_KILLABLE) until the
 627  * @condition evaluates to true or a signal is received.
 628  * The @condition is checked each time the waitqueue @wq is woken up.
 629  *
 630  * wake_up() has to be called after changing any variable that could
 631  * change the result of the wait condition.
 632  *
 633  * The function will return -ERESTARTSYS if it was interrupted by a
 634  * signal and 0 if @condition evaluated to true.
 635  */
 636 #define wait_event_killable(wq, condition)                              \
 637 ({                                                                      \
 638         int __ret = 0;                                                  \
 639         if (!(condition))                                               \
 640                 __ret = __wait_event_killable(wq, condition);           \
 641         __ret;                                                          \
 642 })
 643
 644
 645 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 646         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 647                             spin_unlock_irq(&lock);                     \
 648                             cmd;                                        \
 649                             schedule();                                 \
 650                             spin_lock_irq(&lock))
 651
 652 /**
 653  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
 654  *                           condition is checked under the lock. This
 655  *                           is expected to be called with the lock
 656  *                           taken.
 657  * @wq: the waitqueue to wait on
 658  * @condition: a C expression for the event to wait for
 659  * @lock: a locked spinlock_t, which will be released before cmd
 660  *        and schedule() and reacquired afterwards.
 661  * @cmd: a command which is invoked outside the critical section before
 662  *       sleep
 663  *
 664  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 665  * @condition evaluates to true. The @condition is checked each time
 666  * the waitqueue @wq is woken up.
 667  *
 668  * wake_up() has to be called after changing any variable that could
 669  * change the result of the wait condition.
 670  *
 671  * This is supposed to be called while holding the lock. The lock is
 672  * dropped before invoking the cmd and going to sleep and is reacquired
 673  * afterwards.
 674  */
 675 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
 676 do {                                                                    \
 677         if (condition)                                                  \
 678                 break;                                                  \
 679         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 680 } while (0)
 681
 682 /**
 683  * wait_event_lock_irq - sleep until a condition gets true. The
 684  *                       condition is checked under the lock. This
 685  *                       is expected to be called with the lock
 686  *                       taken.
 687  * @wq: the waitqueue to wait on
 688  * @condition: a C expression for the event to wait for
 689  * @lock: a locked spinlock_t, which will be released before schedule()
 690  *        and reacquired afterwards.
 691  *
 692  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 693  * @condition evaluates to true. The @condition is checked each time
 694  * the waitqueue @wq is woken up.
 695  *
 696  * wake_up() has to be called after changing any variable that could
 697  * change the result of the wait condition.
 698  *
 699  * This is supposed to be called while holding the lock. The lock is
 700  * dropped before going to sleep and is reacquired afterwards.
 701  */
 702 #define wait_event_lock_irq(wq, condition, lock)                        \
 703 do {                                                                    \
 704         if (condition)                                                  \
 705                 break;                                                  \
 706         __wait_event_lock_irq(wq, condition, lock, );                   \
 707 } while (0)
 708
 709
 710 #define __wait_event_interruptible_lock_irq(wq, condition, lock, cmd)   \
 711         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
 712                       spin_unlock_irq(&lock);                           \
 713                       cmd;                                              \
 714                       schedule();                                       \
 715                       spin_lock_irq(&lock))
 716
 717 /**
 718  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
 719  *              The condition is checked under the lock. This is expected to
 720  *              be called with the lock taken.
 721  * @wq: the waitqueue to wait on
 722  * @condition: a C expression for the event to wait for
 723  * @lock: a locked spinlock_t, which will be released before cmd and
 724  *        schedule() and reacquired afterwards.
 725  * @cmd: a command which is invoked outside the critical section before
 726  *       sleep
 727  *
 728  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 729  * @condition evaluates to true or a signal is received. The @condition is
 730  * checked each time the waitqueue @wq is woken up.
 731  *
 732  * wake_up() has to be called after changing any variable that could
 733  * change the result of the wait condition.
 734  *
 735  * This is supposed to be called while holding the lock. The lock is
 736  * dropped before invoking the cmd and going to sleep and is reacquired
 737  * afterwards.
 738  *
 739  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 740  * and 0 if @condition evaluated to true.
 741  */
 742 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
 743 ({                                                                      \
 744         int __ret = 0;                                                  \
 745         if (!(condition))                                               \
 746                 __ret = __wait_event_interruptible_lock_irq(wq,         \
 747                                                 condition, lock, cmd);  \
 748         __ret;                                                          \
 749 })
 750
 751 /**
 752  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
 753  *              The condition is checked under the lock. This is expected
 754  *              to be called with the lock taken.
 755  * @wq: the waitqueue to wait on
 756  * @condition: a C expression for the event to wait for
 757  * @lock: a locked spinlock_t, which will be released before schedule()
 758  *        and reacquired afterwards.
 759  *
 760  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 761  * @condition evaluates to true or signal is received. The @condition is
 762  * checked each time the waitqueue @wq is woken up.
 763  *
 764  * wake_up() has to be called after changing any variable that could
 765  * change the result of the wait condition.
 766  *
 767  * This is supposed to be called while holding the lock. The lock is
 768  * dropped before going to sleep and is reacquired afterwards.
 769  *
 770  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 771  * and 0 if @condition evaluated to true.
 772  */
 773 #define wait_event_interruptible_lock_irq(wq, condition, lock)          \
 774 ({                                                                      \
 775         int __ret = 0;                                                  \
 776         if (!(condition))                                               \
 777                 __ret = __wait_event_interruptible_lock_irq(wq,         \
 778                                                 condition, lock,);      \
 779         __ret;                                                          \
 780 })
 781
 782 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
 783                                                     lock, timeout)      \
 784         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 785                       TASK_INTERRUPTIBLE, 0, timeout,                   \
 786                       spin_unlock_irq(&lock);                           \
 787                       __ret = schedule_timeout(__ret);                  \
 788                       spin_lock_irq(&lock));
 789
 790 /**
 791  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
 792  *              true or a timeout elapses. The condition is checked under
 793  *              the lock. This is expected to be called with the lock taken.
 794  * @wq: the waitqueue to wait on
 795  * @condition: a C expression for the event to wait for
 796  * @lock: a locked spinlock_t, which will be released before schedule()
 797  *        and reacquired afterwards.
 798  * @timeout: timeout, in jiffies
 799  *
 800  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 801  * @condition evaluates to true or signal is received. The @condition is
 802  * checked each time the waitqueue @wq is woken up.
 803  *
 804  * wake_up() has to be called after changing any variable that could
 805  * change the result of the wait condition.
 806  *
 807  * This is supposed to be called while holding the lock. The lock is
 808  * dropped before going to sleep and is reacquired afterwards.
 809  *
 810  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
 811  * was interrupted by a signal, and the remaining jiffies otherwise
 812  * if the condition evaluated to true before the timeout elapsed.
 813  */
 814 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
 815                                                   timeout)              \
 816 ({                                                                      \
 817         long __ret = timeout;                                           \
 818         if (!___wait_cond_timeout(condition))                           \
 819                 __ret = __wait_event_interruptible_lock_irq_timeout(    \
 820                                         wq, condition, lock, timeout);  \
 821         __ret;                                                          \
 822 })
 823
 824 /*
 825  * Waitqueues which are removed from the waitqueue_head at wakeup time
 826  */
 827 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
 828 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
 829 long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state);
 830 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
 831 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key);
 832 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 833 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 834
 835 #define DEFINE_WAIT_FUNC(name, function)                                \
 836         wait_queue_t name = {                                           \
 837                 .private        = current,                              \
 838                 .func           = function,                             \
 839                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
 840         }
 841
 842 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
 843
 844 #define DEFINE_WAIT_BIT(name, word, bit)                                \
 845         struct wait_bit_queue name = {                                  \
 846                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
 847                 .wait   = {                                             \
 848                         .private        = current,                      \
 849                         .func           = wake_bit_function,            \
 850                         .task_list      =                               \
 851                                 LIST_HEAD_INIT((name).wait.task_list),  \
 852                 },                                                      \
 853         }
 854
 855 #define init_wait(wait)                                                 \
 856         do {                                                            \
 857                 (wait)->private = current;                              \
 858                 (wait)->func = autoremove_wake_function;                \
 859                 INIT_LIST_HEAD(&(wait)->task_list);                     \
 860                 (wait)->flags = 0;                                      \
 861         } while (0)
 862
 863
 864 extern int bit_wait(struct wait_bit_key *);
 865 extern int bit_wait_io(struct wait_bit_key *);
 866
 867 /**
 868  * wait_on_bit - wait for a bit to be cleared
 869  * @word: the word being waited on, a kernel virtual address
 870  * @bit: the bit of the word being waited on
 871  * @mode: the task state to sleep in
 872  *
 873  * There is a standard hashed waitqueue table for generic use. This
 874  * is the part of the hashtable's accessor API that waits on a bit.
 875  * For instance, if one were to have waiters on a bitflag, one would
 876  * call wait_on_bit() in threads waiting for the bit to clear.
 877  * One uses wait_on_bit() where one is waiting for the bit to clear,
 878  * but has no intention of setting it.
 879  * Returned value will be zero if the bit was cleared, or non-zero
 880  * if the process received a signal and the mode permitted wakeup
 881  * on that signal.
 882  */
 883 static inline int
 884 wait_on_bit(void *word, int bit, unsigned mode)
 885 {
 886         if (!test_bit(bit, word))
 887                 return 0;
 888         return out_of_line_wait_on_bit(word, bit,
 889                                        bit_wait,
 890                                        mode);
 891 }
 892
 893 /**
 894  * wait_on_bit_io - wait for a bit to be cleared
 895  * @word: the word being waited on, a kernel virtual address
 896  * @bit: the bit of the word being waited on
 897  * @mode: the task state to sleep in
 898  *
 899  * Use the standard hashed waitqueue table to wait for a bit
 900  * to be cleared.  This is similar to wait_on_bit(), but calls
 901  * io_schedule() instead of schedule() for the actual waiting.
 902  *
 903  * Returned value will be zero if the bit was cleared, or non-zero
 904  * if the process received a signal and the mode permitted wakeup
 905  * on that signal.
 906  */
 907 static inline int
 908 wait_on_bit_io(void *word, int bit, unsigned mode)
 909 {
 910         if (!test_bit(bit, word))
 911                 return 0;
 912         return out_of_line_wait_on_bit(word, bit,
 913                                        bit_wait_io,
 914                                        mode);
 915 }
 916
 917 /**
 918  * wait_on_bit_action - 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  * Use the standard hashed waitqueue table to wait for a bit
 925  * to be cleared, and allow the waiting action to be specified.
 926  * This is like wait_on_bit() but allows fine control of how the waiting
 927  * is done.
 928  *
 929  * Returned value will be zero if the bit was cleared, or non-zero
 930  * if the process received a signal and the mode permitted wakeup
 931  * on that signal.
 932  */
 933 static inline int
 934 wait_on_bit_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
 935 {
 936         if (!test_bit(bit, word))
 937                 return 0;
 938         return out_of_line_wait_on_bit(word, bit, action, mode);
 939 }
 940
 941 /**
 942  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
 943  * @word: the word being waited on, a kernel virtual address
 944  * @bit: the bit of the word being waited on
 945  * @mode: the task state to sleep in
 946  *
 947  * There is a standard hashed waitqueue table for generic use. This
 948  * is the part of the hashtable's accessor API that waits on a bit
 949  * when one intends to set it, for instance, trying to lock bitflags.
 950  * For instance, if one were to have waiters trying to set bitflag
 951  * and waiting for it to clear before setting it, one would call
 952  * wait_on_bit() in threads waiting to be able to set the bit.
 953  * One uses wait_on_bit_lock() where one is waiting for the bit to
 954  * clear with the intention of setting it, and when done, clearing it.
 955  *
 956  * Returns zero if the bit was (eventually) found to be clear and was
 957  * set.  Returns non-zero if a signal was delivered to the process and
 958  * the @mode allows that signal to wake the process.
 959  */
 960 static inline int
 961 wait_on_bit_lock(void *word, int bit, unsigned mode)
 962 {
 963         if (!test_and_set_bit(bit, word))
 964                 return 0;
 965         return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode);
 966 }
 967
 968 /**
 969  * wait_on_bit_lock_io - wait for a bit to be cleared, when wanting to set it
 970  * @word: the word being waited on, a kernel virtual address
 971  * @bit: the bit of the word being waited on
 972  * @mode: the task state to sleep in
 973  *
 974  * Use the standard hashed waitqueue table to wait for a bit
 975  * to be cleared and then to atomically set it.  This is similar
 976  * to wait_on_bit(), but calls io_schedule() instead of schedule()
 977  * for the actual waiting.
 978  *
 979  * Returns zero if the bit was (eventually) found to be clear and was
 980  * set.  Returns non-zero if a signal was delivered to the process and
 981  * the @mode allows that signal to wake the process.
 982  */
 983 static inline int
 984 wait_on_bit_lock_io(void *word, int bit, unsigned mode)
 985 {
 986         if (!test_and_set_bit(bit, word))
 987                 return 0;
 988         return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode);
 989 }
 990
 991 /**
 992  * wait_on_bit_lock_action - wait for a bit to be cleared, when wanting to set it
 993  * @word: the word being waited on, a kernel virtual address
 994  * @bit: the bit of the word being waited on
 995  * @action: the function used to sleep, which may take special actions
 996  * @mode: the task state to sleep in
 997  *
 998  * Use the standard hashed waitqueue table to wait for a bit
 999  * to be cleared and then to set it, and allow the waiting action
1000  * to be specified.
1001  * This is like wait_on_bit() but allows fine control of how the waiting
1002  * is done.
1003  *
1004  * Returns zero if the bit was (eventually) found to be clear and was
1005  * set.  Returns non-zero if a signal was delivered to the process and
1006  * the @mode allows that signal to wake the process.
1007  */
1008 static inline int
1009 wait_on_bit_lock_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
1010 {
1011         if (!test_and_set_bit(bit, word))
1012                 return 0;
1013         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
1014 }
1015
1016 /**
1017  * wait_on_atomic_t - Wait for an atomic_t to become 0
1018  * @val: The atomic value being waited on, a kernel virtual address
1019  * @action: the function used to sleep, which may take special actions
1020  * @mode: the task state to sleep in
1021  *
1022  * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
1023  * the purpose of getting a waitqueue, but we set the key to a bit number
1024  * outside of the target 'word'.
1025  */
1026 static inline
1027 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
1028 {
1029         if (atomic_read(val) == 0)
1030                 return 0;
1031         return out_of_line_wait_on_atomic_t(val, action, mode);
1032 }
1033
1034 #endif /* _LINUX_WAIT_H */