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 };
  29
  30 struct wait_bit_queue {
  31         struct wait_bit_key     key;
  32         wait_queue_t            wait;
  33 };
  34
  35 struct __wait_queue_head {
  36         spinlock_t              lock;
  37         struct list_head        task_list;
  38 };
  39 typedef struct __wait_queue_head wait_queue_head_t;
  40
  41 struct task_struct;
  42
  43 /*
  44  * Macros for declaration and initialisaton of the datatypes
  45  */
  46
  47 #define __WAITQUEUE_INITIALIZER(name, tsk) {                            \
  48         .private        = tsk,                                          \
  49         .func           = default_wake_function,                        \
  50         .task_list      = { NULL, NULL } }
  51
  52 #define DECLARE_WAITQUEUE(name, tsk)                                    \
  53         wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
  54
  55 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                           \
  56         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),              \
  57         .task_list      = { &(name).task_list, &(name).task_list } }
  58
  59 #define DECLARE_WAIT_QUEUE_HEAD(name) \
  60         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
  61
  62 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)                           \
  63         { .flags = word, .bit_nr = bit, }
  64
  65 #define __WAIT_ATOMIC_T_KEY_INITIALIZER(p)                              \
  66         { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }
  67
  68 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
  69
  70 #define init_waitqueue_head(q)                          \
  71         do {                                            \
  72                 static struct lock_class_key __key;     \
  73                                                         \
  74                 __init_waitqueue_head((q), #q, &__key); \
  75         } while (0)
  76
  77 #ifdef CONFIG_LOCKDEP
  78 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
  79         ({ init_waitqueue_head(&name); name; })
  80 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
  81         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
  82 #else
  83 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
  84 #endif
  85
  86 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
  87 {
  88         q->flags        = 0;
  89         q->private      = p;
  90         q->func         = default_wake_function;
  91 }
  92
  93 static inline void
  94 init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func)
  95 {
  96         q->flags        = 0;
  97         q->private      = NULL;
  98         q->func         = func;
  99 }
 100
 101 static inline int waitqueue_active(wait_queue_head_t *q)
 102 {
 103         return !list_empty(&q->task_list);
 104 }
 105
 106 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 107 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
 108 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 109
 110 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
 111 {
 112         list_add(&new->task_list, &head->task_list);
 113 }
 114
 115 /*
 116  * Used for wake-one threads:
 117  */
 118 static inline void
 119 __add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
 120 {
 121         wait->flags |= WQ_FLAG_EXCLUSIVE;
 122         __add_wait_queue(q, wait);
 123 }
 124
 125 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
 126                                          wait_queue_t *new)
 127 {
 128         list_add_tail(&new->task_list, &head->task_list);
 129 }
 130
 131 static inline void
 132 __add_wait_queue_tail_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
 133 {
 134         wait->flags |= WQ_FLAG_EXCLUSIVE;
 135         __add_wait_queue_tail(q, wait);
 136 }
 137
 138 static inline void
 139 __remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old)
 140 {
 141         list_del(&old->task_list);
 142 }
 143
 144 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 145 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
 146 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 147 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
 148 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
 149 void __wake_up_bit(wait_queue_head_t *, void *, int);
 150 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
 151 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
 152 void wake_up_bit(void *, int);
 153 void wake_up_atomic_t(atomic_t *);
 154 int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned);
 155 int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned);
 156 int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned);
 157 wait_queue_head_t *bit_waitqueue(void *, int);
 158
 159 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
 160 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
 161 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
 162 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL, 1)
 163 #define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)
 164
 165 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 166 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
 167 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
 168 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
 169
 170 /*
 171  * Wakeup macros to be used to report events to the targets.
 172  */
 173 #define wake_up_poll(x, m)                                              \
 174         __wake_up(x, TASK_NORMAL, 1, (void *) (m))
 175 #define wake_up_locked_poll(x, m)                                       \
 176         __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
 177 #define wake_up_interruptible_poll(x, m)                                \
 178         __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
 179 #define wake_up_interruptible_sync_poll(x, m)                           \
 180         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
 181
 182 #define ___wait_cond_timeout(condition)                                 \
 183 ({                                                                      \
 184         bool __cond = (condition);                                      \
 185         if (__cond && !__ret)                                           \
 186                 __ret = 1;                                              \
 187         __cond || !__ret;                                               \
 188 })
 189
 190 #define ___wait_signal_pending(state)                                   \
 191         ((state == TASK_INTERRUPTIBLE && signal_pending(current)) ||    \
 192          (state == TASK_KILLABLE && fatal_signal_pending(current)))
 193
 194 #define ___wait_event(wq, condition, state, exclusive, ret, cmd)        \
 195 ({                                                                      \
 196         __label__ __out;                                                \
 197         DEFINE_WAIT(__wait);                                            \
 198         long __ret = ret;                                               \
 199                                                                         \
 200         for (;;) {                                                      \
 201                 if (exclusive)                                          \
 202                         prepare_to_wait_exclusive(&wq, &__wait, state); \
 203                 else                                                    \
 204                         prepare_to_wait(&wq, &__wait, state);           \
 205                                                                         \
 206                 if (condition)                                          \
 207                         break;                                          \
 208                                                                         \
 209                 if (___wait_signal_pending(state)) {                    \
 210                         __ret = -ERESTARTSYS;                           \
 211                         if (exclusive) {                                \
 212                                 abort_exclusive_wait(&wq, &__wait,      \
 213                                                      state, NULL);      \
 214                                 goto __out;                             \
 215                         }                                               \
 216                         break;                                          \
 217                 }                                                       \
 218                                                                         \
 219                 cmd;                                                    \
 220         }                                                               \
 221         finish_wait(&wq, &__wait);                                      \
 222 __out:  __ret;                                                          \
 223 })
 224
 225 #define __wait_event(wq, condition)                                     \
 226         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 227                             schedule())
 228
 229 /**
 230  * wait_event - sleep until a condition gets true
 231  * @wq: the waitqueue to wait on
 232  * @condition: a C expression for the event to wait for
 233  *
 234  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 235  * @condition evaluates to true. The @condition is checked each time
 236  * the waitqueue @wq is woken up.
 237  *
 238  * wake_up() has to be called after changing any variable that could
 239  * change the result of the wait condition.
 240  */
 241 #define wait_event(wq, condition)                                       \
 242 do {                                                                    \
 243         if (condition)                                                  \
 244                 break;                                                  \
 245         __wait_event(wq, condition);                                    \
 246 } while (0)
 247
 248 #define __wait_event_timeout(wq, condition, timeout)                    \
 249         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 250                       TASK_UNINTERRUPTIBLE, 0, timeout,                 \
 251                       __ret = schedule_timeout(__ret))
 252
 253 /**
 254  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 255  * @wq: the waitqueue to wait on
 256  * @condition: a C expression for the event to wait for
 257  * @timeout: timeout, in jiffies
 258  *
 259  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 260  * @condition evaluates to true. The @condition is checked each time
 261  * the waitqueue @wq is woken up.
 262  *
 263  * wake_up() has to be called after changing any variable that could
 264  * change the result of the wait condition.
 265  *
 266  * The function returns 0 if the @timeout elapsed, or the remaining
 267  * jiffies (at least 1) if the @condition evaluated to %true before
 268  * the @timeout elapsed.
 269  */
 270 #define wait_event_timeout(wq, condition, timeout)                      \
 271 ({                                                                      \
 272         long __ret = timeout;                                           \
 273         if (!(condition))                                               \
 274                 __ret = __wait_event_timeout(wq, condition, timeout);   \
 275         __ret;                                                          \
 276 })
 277
 278 #define __wait_event_interruptible(wq, condition)                       \
 279         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
 280                       schedule())
 281
 282 /**
 283  * wait_event_interruptible - sleep until a condition gets true
 284  * @wq: the waitqueue to wait on
 285  * @condition: a C expression for the event to wait for
 286  *
 287  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 288  * @condition evaluates to true or a signal is received.
 289  * The @condition is checked each time the waitqueue @wq is woken up.
 290  *
 291  * wake_up() has to be called after changing any variable that could
 292  * change the result of the wait condition.
 293  *
 294  * The function will return -ERESTARTSYS if it was interrupted by a
 295  * signal and 0 if @condition evaluated to true.
 296  */
 297 #define wait_event_interruptible(wq, condition)                         \
 298 ({                                                                      \
 299         int __ret = 0;                                                  \
 300         if (!(condition))                                               \
 301                 __ret = __wait_event_interruptible(wq, condition);      \
 302         __ret;                                                          \
 303 })
 304
 305 #define __wait_event_interruptible_timeout(wq, condition, timeout)      \
 306         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 307                       TASK_INTERRUPTIBLE, 0, timeout,                   \
 308                       __ret = schedule_timeout(__ret))
 309
 310 /**
 311  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 312  * @wq: the waitqueue to wait on
 313  * @condition: a C expression for the event to wait for
 314  * @timeout: timeout, in jiffies
 315  *
 316  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 317  * @condition evaluates to true or a signal is received.
 318  * The @condition is checked each time the waitqueue @wq is woken up.
 319  *
 320  * wake_up() has to be called after changing any variable that could
 321  * change the result of the wait condition.
 322  *
 323  * Returns:
 324  * 0 if the @timeout elapsed, -%ERESTARTSYS if it was interrupted by
 325  * a signal, or the remaining jiffies (at least 1) if the @condition
 326  * evaluated to %true before the @timeout elapsed.
 327  */
 328 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
 329 ({                                                                      \
 330         long __ret = timeout;                                           \
 331         if (!(condition))                                               \
 332                 __ret = __wait_event_interruptible_timeout(wq,          \
 333                                                 condition, timeout);    \
 334         __ret;                                                          \
 335 })
 336
 337 #define __wait_event_hrtimeout(wq, condition, timeout, state)           \
 338 ({                                                                      \
 339         int __ret = 0;                                                  \
 340         struct hrtimer_sleeper __t;                                     \
 341                                                                         \
 342         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
 343                               HRTIMER_MODE_REL);                        \
 344         hrtimer_init_sleeper(&__t, current);                            \
 345         if ((timeout).tv64 != KTIME_MAX)                                \
 346                 hrtimer_start_range_ns(&__t.timer, timeout,             \
 347                                        current->timer_slack_ns,         \
 348                                        HRTIMER_MODE_REL);               \
 349                                                                         \
 350         __ret = ___wait_event(wq, condition, state, 0, 0,               \
 351                 if (!__t.task) {                                        \
 352                         __ret = -ETIME;                                 \
 353                         break;                                          \
 354                 }                                                       \
 355                 schedule());                                            \
 356                                                                         \
 357         hrtimer_cancel(&__t.timer);                                     \
 358         destroy_hrtimer_on_stack(&__t.timer);                           \
 359         __ret;                                                          \
 360 })
 361
 362 /**
 363  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
 364  * @wq: the waitqueue to wait on
 365  * @condition: a C expression for the event to wait for
 366  * @timeout: timeout, as a ktime_t
 367  *
 368  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 369  * @condition evaluates to true or a signal is received.
 370  * The @condition is checked each time the waitqueue @wq is woken up.
 371  *
 372  * wake_up() has to be called after changing any variable that could
 373  * change the result of the wait condition.
 374  *
 375  * The function returns 0 if @condition became true, or -ETIME if the timeout
 376  * elapsed.
 377  */
 378 #define wait_event_hrtimeout(wq, condition, timeout)                    \
 379 ({                                                                      \
 380         int __ret = 0;                                                  \
 381         if (!(condition))                                               \
 382                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 383                                                TASK_UNINTERRUPTIBLE);   \
 384         __ret;                                                          \
 385 })
 386
 387 /**
 388  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
 389  * @wq: the waitqueue to wait on
 390  * @condition: a C expression for the event to wait for
 391  * @timeout: timeout, as a ktime_t
 392  *
 393  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 394  * @condition evaluates to true or a signal is received.
 395  * The @condition is checked each time the waitqueue @wq is woken up.
 396  *
 397  * wake_up() has to be called after changing any variable that could
 398  * change the result of the wait condition.
 399  *
 400  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
 401  * interrupted by a signal, or -ETIME if the timeout elapsed.
 402  */
 403 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
 404 ({                                                                      \
 405         long __ret = 0;                                                 \
 406         if (!(condition))                                               \
 407                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 408                                                TASK_INTERRUPTIBLE);     \
 409         __ret;                                                          \
 410 })
 411
 412 #define __wait_event_interruptible_exclusive(wq, condition)             \
 413         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
 414                       schedule())
 415
 416 #define wait_event_interruptible_exclusive(wq, condition)               \
 417 ({                                                                      \
 418         int __ret = 0;                                                  \
 419         if (!(condition))                                               \
 420                 __ret = __wait_event_interruptible_exclusive(wq, condition);\
 421         __ret;                                                          \
 422 })
 423
 424
 425 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
 426 ({                                                                      \
 427         int __ret = 0;                                                  \
 428         DEFINE_WAIT(__wait);                                            \
 429         if (exclusive)                                                  \
 430                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
 431         do {                                                            \
 432                 if (likely(list_empty(&__wait.task_list)))              \
 433                         __add_wait_queue_tail(&(wq), &__wait);          \
 434                 set_current_state(TASK_INTERRUPTIBLE);                  \
 435                 if (signal_pending(current)) {                          \
 436                         __ret = -ERESTARTSYS;                           \
 437                         break;                                          \
 438                 }                                                       \
 439                 if (irq)                                                \
 440                         spin_unlock_irq(&(wq).lock);                    \
 441                 else                                                    \
 442                         spin_unlock(&(wq).lock);                        \
 443                 schedule();                                             \
 444                 if (irq)                                                \
 445                         spin_lock_irq(&(wq).lock);                      \
 446                 else                                                    \
 447                         spin_lock(&(wq).lock);                          \
 448         } while (!(condition));                                         \
 449         __remove_wait_queue(&(wq), &__wait);                            \
 450         __set_current_state(TASK_RUNNING);                              \
 451         __ret;                                                          \
 452 })
 453
 454
 455 /**
 456  * wait_event_interruptible_locked - sleep until a condition gets true
 457  * @wq: the waitqueue to wait on
 458  * @condition: a C expression for the event to wait for
 459  *
 460  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 461  * @condition evaluates to true or a signal is received.
 462  * The @condition is checked each time the waitqueue @wq is woken up.
 463  *
 464  * It must be called with wq.lock being held.  This spinlock is
 465  * unlocked while sleeping but @condition testing is done while lock
 466  * is held and when this macro exits the lock is held.
 467  *
 468  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 469  * functions which must match the way they are locked/unlocked outside
 470  * of this macro.
 471  *
 472  * wake_up_locked() has to be called after changing any variable that could
 473  * change the result of the wait condition.
 474  *
 475  * The function will return -ERESTARTSYS if it was interrupted by a
 476  * signal and 0 if @condition evaluated to true.
 477  */
 478 #define wait_event_interruptible_locked(wq, condition)                  \
 479         ((condition)                                                    \
 480          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
 481
 482 /**
 483  * wait_event_interruptible_locked_irq - sleep until a condition gets true
 484  * @wq: the waitqueue to wait on
 485  * @condition: a C expression for the event to wait for
 486  *
 487  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 488  * @condition evaluates to true or a signal is received.
 489  * The @condition is checked each time the waitqueue @wq is woken up.
 490  *
 491  * It must be called with wq.lock being held.  This spinlock is
 492  * unlocked while sleeping but @condition testing is done while lock
 493  * is held and when this macro exits the lock is held.
 494  *
 495  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 496  * functions which must match the way they are locked/unlocked outside
 497  * of this macro.
 498  *
 499  * wake_up_locked() has to be called after changing any variable that could
 500  * change the result of the wait condition.
 501  *
 502  * The function will return -ERESTARTSYS if it was interrupted by a
 503  * signal and 0 if @condition evaluated to true.
 504  */
 505 #define wait_event_interruptible_locked_irq(wq, condition)              \
 506         ((condition)                                                    \
 507          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
 508
 509 /**
 510  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
 511  * @wq: the waitqueue to wait on
 512  * @condition: a C expression for the event to wait for
 513  *
 514  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 515  * @condition evaluates to true or a signal is received.
 516  * The @condition is checked each time the waitqueue @wq is woken up.
 517  *
 518  * It must be called with wq.lock being held.  This spinlock is
 519  * unlocked while sleeping but @condition testing is done while lock
 520  * is held and when this macro exits the lock is held.
 521  *
 522  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 523  * functions which must match the way they are locked/unlocked outside
 524  * of this macro.
 525  *
 526  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 527  * set thus when other process waits process on the list if this
 528  * process is awaken further processes are not considered.
 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_exclusive_locked(wq, condition)        \
 537         ((condition)                                                    \
 538          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
 539
 540 /**
 541  * wait_event_interruptible_exclusive_locked_irq - sleep 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_irq()/spin_unlock_irq()
 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_irq(wq, condition)    \
 568         ((condition)                                                    \
 569          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
 570
 571
 572 #define __wait_event_killable(wq, condition)                            \
 573         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
 574
 575 /**
 576  * wait_event_killable - sleep until a condition gets true
 577  * @wq: the waitqueue to wait on
 578  * @condition: a C expression for the event to wait for
 579  *
 580  * The process is put to sleep (TASK_KILLABLE) until the
 581  * @condition evaluates to true or a signal is received.
 582  * The @condition is checked each time the waitqueue @wq is woken up.
 583  *
 584  * wake_up() has to be called after changing any variable that could
 585  * change the result of the wait condition.
 586  *
 587  * The function will return -ERESTARTSYS if it was interrupted by a
 588  * signal and 0 if @condition evaluated to true.
 589  */
 590 #define wait_event_killable(wq, condition)                              \
 591 ({                                                                      \
 592         int __ret = 0;                                                  \
 593         if (!(condition))                                               \
 594                 __ret = __wait_event_killable(wq, condition);           \
 595         __ret;                                                          \
 596 })
 597
 598
 599 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 600         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 601                             spin_unlock_irq(&lock);                     \
 602                             cmd;                                        \
 603                             schedule();                                 \
 604                             spin_lock_irq(&lock))
 605
 606 /**
 607  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
 608  *                           condition is checked under the lock. This
 609  *                           is expected to be called with the lock
 610  *                           taken.
 611  * @wq: the waitqueue to wait on
 612  * @condition: a C expression for the event to wait for
 613  * @lock: a locked spinlock_t, which will be released before cmd
 614  *        and schedule() and reacquired afterwards.
 615  * @cmd: a command which is invoked outside the critical section before
 616  *       sleep
 617  *
 618  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 619  * @condition evaluates to true. The @condition is checked each time
 620  * the waitqueue @wq is woken up.
 621  *
 622  * wake_up() has to be called after changing any variable that could
 623  * change the result of the wait condition.
 624  *
 625  * This is supposed to be called while holding the lock. The lock is
 626  * dropped before invoking the cmd and going to sleep and is reacquired
 627  * afterwards.
 628  */
 629 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
 630 do {                                                                    \
 631         if (condition)                                                  \
 632                 break;                                                  \
 633         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 634 } while (0)
 635
 636 /**
 637  * wait_event_lock_irq - sleep until a condition gets true. The
 638  *                       condition is checked under the lock. This
 639  *                       is expected to be called with the lock
 640  *                       taken.
 641  * @wq: the waitqueue to wait on
 642  * @condition: a C expression for the event to wait for
 643  * @lock: a locked spinlock_t, which will be released before schedule()
 644  *        and reacquired afterwards.
 645  *
 646  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 647  * @condition evaluates to true. The @condition is checked each time
 648  * the waitqueue @wq is woken up.
 649  *
 650  * wake_up() has to be called after changing any variable that could
 651  * change the result of the wait condition.
 652  *
 653  * This is supposed to be called while holding the lock. The lock is
 654  * dropped before going to sleep and is reacquired afterwards.
 655  */
 656 #define wait_event_lock_irq(wq, condition, lock)                        \
 657 do {                                                                    \
 658         if (condition)                                                  \
 659                 break;                                                  \
 660         __wait_event_lock_irq(wq, condition, lock, );                   \
 661 } while (0)
 662
 663
 664 #define __wait_event_interruptible_lock_irq(wq, condition, lock, cmd)   \
 665         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
 666                       spin_unlock_irq(&lock);                           \
 667                       cmd;                                              \
 668                       schedule();                                       \
 669                       spin_lock_irq(&lock))
 670
 671 /**
 672  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
 673  *              The condition is checked under the lock. This is expected to
 674  *              be called with the lock taken.
 675  * @wq: the waitqueue to wait on
 676  * @condition: a C expression for the event to wait for
 677  * @lock: a locked spinlock_t, which will be released before cmd and
 678  *        schedule() and reacquired afterwards.
 679  * @cmd: a command which is invoked outside the critical section before
 680  *       sleep
 681  *
 682  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 683  * @condition evaluates to true or a signal is received. The @condition is
 684  * checked each time the waitqueue @wq is woken up.
 685  *
 686  * wake_up() has to be called after changing any variable that could
 687  * change the result of the wait condition.
 688  *
 689  * This is supposed to be called while holding the lock. The lock is
 690  * dropped before invoking the cmd and going to sleep and is reacquired
 691  * afterwards.
 692  *
 693  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 694  * and 0 if @condition evaluated to true.
 695  */
 696 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
 697 ({                                                                      \
 698         int __ret = 0;                                                  \
 699         if (!(condition))                                               \
 700                 __ret = __wait_event_interruptible_lock_irq(wq,         \
 701                                                 condition, lock, cmd);  \
 702         __ret;                                                          \
 703 })
 704
 705 /**
 706  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
 707  *              The condition is checked under the lock. This is expected
 708  *              to be called with the lock taken.
 709  * @wq: the waitqueue to wait on
 710  * @condition: a C expression for the event to wait for
 711  * @lock: a locked spinlock_t, which will be released before schedule()
 712  *        and reacquired afterwards.
 713  *
 714  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 715  * @condition evaluates to true or signal is received. The @condition is
 716  * checked each time the waitqueue @wq is woken up.
 717  *
 718  * wake_up() has to be called after changing any variable that could
 719  * change the result of the wait condition.
 720  *
 721  * This is supposed to be called while holding the lock. The lock is
 722  * dropped before going to sleep and is reacquired afterwards.
 723  *
 724  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 725  * and 0 if @condition evaluated to true.
 726  */
 727 #define wait_event_interruptible_lock_irq(wq, condition, lock)          \
 728 ({                                                                      \
 729         int __ret = 0;                                                  \
 730         if (!(condition))                                               \
 731                 __ret = __wait_event_interruptible_lock_irq(wq,         \
 732                                                 condition, lock,)       \
 733         __ret;                                                          \
 734 })
 735
 736 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
 737                                                     lock, timeout)      \
 738         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 739                       TASK_INTERRUPTIBLE, 0, ret,                       \
 740                       spin_unlock_irq(&lock);                           \
 741                       __ret = schedule_timeout(__ret);                  \
 742                       spin_lock_irq(&lock));
 743
 744 /**
 745  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
 746  *              true or a timeout elapses. The condition is checked under
 747  *              the lock. This is expected to be called with the lock taken.
 748  * @wq: the waitqueue to wait on
 749  * @condition: a C expression for the event to wait for
 750  * @lock: a locked spinlock_t, which will be released before schedule()
 751  *        and reacquired afterwards.
 752  * @timeout: timeout, in jiffies
 753  *
 754  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 755  * @condition evaluates to true or signal is received. The @condition is
 756  * checked each time the waitqueue @wq is woken up.
 757  *
 758  * wake_up() has to be called after changing any variable that could
 759  * change the result of the wait condition.
 760  *
 761  * This is supposed to be called while holding the lock. The lock is
 762  * dropped before going to sleep and is reacquired afterwards.
 763  *
 764  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
 765  * was interrupted by a signal, and the remaining jiffies otherwise
 766  * if the condition evaluated to true before the timeout elapsed.
 767  */
 768 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
 769                                                   timeout)              \
 770 ({                                                                      \
 771         long __ret = timeout;                                           \
 772         if (!(condition))                                               \
 773                 __ret = __wait_event_interruptible_lock_irq_timeout(    \
 774                                         wq, condition, lock, timeout);  \
 775         __ret;                                                          \
 776 })
 777
 778
 779 /*
 780  * These are the old interfaces to sleep waiting for an event.
 781  * They are racy.  DO NOT use them, use the wait_event* interfaces above.
 782  * We plan to remove these interfaces.
 783  */
 784 extern void sleep_on(wait_queue_head_t *q);
 785 extern long sleep_on_timeout(wait_queue_head_t *q, signed long timeout);
 786 extern void interruptible_sleep_on(wait_queue_head_t *q);
 787 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q, signed long timeout);
 788
 789 /*
 790  * Waitqueues which are removed from the waitqueue_head at wakeup time
 791  */
 792 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
 793 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
 794 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
 795 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key);
 796 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 797 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 798
 799 #define DEFINE_WAIT_FUNC(name, function)                                \
 800         wait_queue_t name = {                                           \
 801                 .private        = current,                              \
 802                 .func           = function,                             \
 803                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
 804         }
 805
 806 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
 807
 808 #define DEFINE_WAIT_BIT(name, word, bit)                                \
 809         struct wait_bit_queue name = {                                  \
 810                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
 811                 .wait   = {                                             \
 812                         .private        = current,                      \
 813                         .func           = wake_bit_function,            \
 814                         .task_list      =                               \
 815                                 LIST_HEAD_INIT((name).wait.task_list),  \
 816                 },                                                      \
 817         }
 818
 819 #define init_wait(wait)                                                 \
 820         do {                                                            \
 821                 (wait)->private = current;                              \
 822                 (wait)->func = autoremove_wake_function;                \
 823                 INIT_LIST_HEAD(&(wait)->task_list);                     \
 824                 (wait)->flags = 0;                                      \
 825         } while (0)
 826
 827 /**
 828  * wait_on_bit - wait for a bit to be cleared
 829  * @word: the word being waited on, a kernel virtual address
 830  * @bit: the bit of the word being waited on
 831  * @action: the function used to sleep, which may take special actions
 832  * @mode: the task state to sleep in
 833  *
 834  * There is a standard hashed waitqueue table for generic use. This
 835  * is the part of the hashtable's accessor API that waits on a bit.
 836  * For instance, if one were to have waiters on a bitflag, one would
 837  * call wait_on_bit() in threads waiting for the bit to clear.
 838  * One uses wait_on_bit() where one is waiting for the bit to clear,
 839  * but has no intention of setting it.
 840  */
 841 static inline int
 842 wait_on_bit(void *word, int bit, int (*action)(void *), unsigned mode)
 843 {
 844         if (!test_bit(bit, word))
 845                 return 0;
 846         return out_of_line_wait_on_bit(word, bit, action, mode);
 847 }
 848
 849 /**
 850  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
 851  * @word: the word being waited on, a kernel virtual address
 852  * @bit: the bit of the word being waited on
 853  * @action: the function used to sleep, which may take special actions
 854  * @mode: the task state to sleep in
 855  *
 856  * There is a standard hashed waitqueue table for generic use. This
 857  * is the part of the hashtable's accessor API that waits on a bit
 858  * when one intends to set it, for instance, trying to lock bitflags.
 859  * For instance, if one were to have waiters trying to set bitflag
 860  * and waiting for it to clear before setting it, one would call
 861  * wait_on_bit() in threads waiting to be able to set the bit.
 862  * One uses wait_on_bit_lock() where one is waiting for the bit to
 863  * clear with the intention of setting it, and when done, clearing it.
 864  */
 865 static inline int
 866 wait_on_bit_lock(void *word, int bit, int (*action)(void *), unsigned mode)
 867 {
 868         if (!test_and_set_bit(bit, word))
 869                 return 0;
 870         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
 871 }
 872
 873 /**
 874  * wait_on_atomic_t - Wait for an atomic_t to become 0
 875  * @val: The atomic value being waited on, a kernel virtual address
 876  * @action: the function used to sleep, which may take special actions
 877  * @mode: the task state to sleep in
 878  *
 879  * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
 880  * the purpose of getting a waitqueue, but we set the key to a bit number
 881  * outside of the target 'word'.
 882  */
 883 static inline
 884 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
 885 {
 886         if (atomic_read(val) == 0)
 887                 return 0;
 888         return out_of_line_wait_on_atomic_t(val, action, mode);
 889 }
 890
 891 #endif /* _LINUX_WAIT_H */