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 /* __wait_queue::flags */
  17 #define WQ_FLAG_EXCLUSIVE       0x01
  18 #define WQ_FLAG_WOKEN           0x02
  19
  20 struct __wait_queue {
  21         unsigned int            flags;
  22         void                    *private;
  23         wait_queue_func_t       func;
  24         struct list_head        task_list;
  25 };
  26
  27 struct wait_bit_key {
  28         void                    *flags;
  29         int                     bit_nr;
  30 #define WAIT_ATOMIC_T_BIT_NR    -1
  31         unsigned long           timeout;
  32 };
  33
  34 struct wait_bit_queue {
  35         struct wait_bit_key     key;
  36         wait_queue_t            wait;
  37 };
  38
  39 struct __wait_queue_head {
  40         spinlock_t              lock;
  41         struct list_head        task_list;
  42 };
  43 typedef struct __wait_queue_head wait_queue_head_t;
  44
  45 struct task_struct;
  46
  47 /*
  48  * Macros for declaration and initialisaton of the datatypes
  49  */
  50
  51 #define __WAITQUEUE_INITIALIZER(name, tsk) {                            \
  52         .private        = tsk,                                          \
  53         .func           = default_wake_function,                        \
  54         .task_list      = { NULL, NULL } }
  55
  56 #define DECLARE_WAITQUEUE(name, tsk)                                    \
  57         wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
  58
  59 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                           \
  60         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),              \
  61         .task_list      = { &(name).task_list, &(name).task_list } }
  62
  63 #define DECLARE_WAIT_QUEUE_HEAD(name) \
  64         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
  65
  66 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)                           \
  67         { .flags = word, .bit_nr = bit, }
  68
  69 #define __WAIT_ATOMIC_T_KEY_INITIALIZER(p)                              \
  70         { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }
  71
  72 extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
  73
  74 #define init_waitqueue_head(q)                          \
  75         do {                                            \
  76                 static struct lock_class_key __key;     \
  77                                                         \
  78                 __init_waitqueue_head((q), #q, &__key); \
  79         } while (0)
  80
  81 #ifdef CONFIG_LOCKDEP
  82 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
  83         ({ init_waitqueue_head(&name); name; })
  84 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
  85         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
  86 #else
  87 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
  88 #endif
  89
  90 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
  91 {
  92         q->flags        = 0;
  93         q->private      = p;
  94         q->func         = default_wake_function;
  95 }
  96
  97 static inline void
  98 init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func)
  99 {
 100         q->flags        = 0;
 101         q->private      = NULL;
 102         q->func         = func;
 103 }
 104
 105 static inline int waitqueue_active(wait_queue_head_t *q)
 106 {
 107         return !list_empty(&q->task_list);
 108 }
 109
 110 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 111 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
 112 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 113
 114 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
 115 {
 116         list_add(&new->task_list, &head->task_list);
 117 }
 118
 119 /*
 120  * Used for wake-one threads:
 121  */
 122 static inline void
 123 __add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
 124 {
 125         wait->flags |= WQ_FLAG_EXCLUSIVE;
 126         __add_wait_queue(q, wait);
 127 }
 128
 129 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
 130                                          wait_queue_t *new)
 131 {
 132         list_add_tail(&new->task_list, &head->task_list);
 133 }
 134
 135 static inline void
 136 __add_wait_queue_tail_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
 137 {
 138         wait->flags |= WQ_FLAG_EXCLUSIVE;
 139         __add_wait_queue_tail(q, wait);
 140 }
 141
 142 static inline void
 143 __remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old)
 144 {
 145         list_del(&old->task_list);
 146 }
 147
 148 typedef int wait_bit_action_f(struct wait_bit_key *);
 149 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 150 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
 151 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 152 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
 153 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
 154 void __wake_up_bit(wait_queue_head_t *, void *, int);
 155 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
 156 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
 157 void wake_up_bit(void *, int);
 158 void wake_up_atomic_t(atomic_t *);
 159 int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned);
 160 int out_of_line_wait_on_bit_timeout(void *, int, wait_bit_action_f *, unsigned, unsigned long);
 161 int out_of_line_wait_on_bit_lock(void *, int, wait_bit_action_f *, unsigned);
 162 int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned);
 163 wait_queue_head_t *bit_waitqueue(void *, int);
 164
 165 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
 166 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
 167 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
 168 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL, 1)
 169 #define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)
 170
 171 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 172 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
 173 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
 174 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
 175
 176 /*
 177  * Wakeup macros to be used to report events to the targets.
 178  */
 179 #define wake_up_poll(x, m)                                              \
 180         __wake_up(x, TASK_NORMAL, 1, (void *) (m))
 181 #define wake_up_locked_poll(x, m)                                       \
 182         __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
 183 #define wake_up_interruptible_poll(x, m)                                \
 184         __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
 185 #define wake_up_interruptible_sync_poll(x, m)                           \
 186         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
 187
 188 #define ___wait_cond_timeout(condition)                                 \
 189 ({                                                                      \
 190         bool __cond = (condition);                                      \
 191         if (__cond && !__ret)                                           \
 192                 __ret = 1;                                              \
 193         __cond || !__ret;                                               \
 194 })
 195
 196 #define ___wait_is_interruptible(state)                                 \
 197         (!__builtin_constant_p(state) ||                                \
 198                 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE)  \
 199
 200 /*
 201  * The below macro ___wait_event() has an explicit shadow of the __ret
 202  * variable when used from the wait_event_*() macros.
 203  *
 204  * This is so that both can use the ___wait_cond_timeout() construct
 205  * to wrap the condition.
 206  *
 207  * The type inconsistency of the wait_event_*() __ret variable is also
 208  * on purpose; we use long where we can return timeout values and int
 209  * otherwise.
 210  */
 211
 212 #define ___wait_event(wq, condition, state, exclusive, ret, cmd)        \
 213 ({                                                                      \
 214         __label__ __out;                                                \
 215         wait_queue_t __wait;                                            \
 216         long __ret = ret;       /* explicit shadow */                   \
 217                                                                         \
 218         INIT_LIST_HEAD(&__wait.task_list);                              \
 219         if (exclusive)                                                  \
 220                 __wait.flags = WQ_FLAG_EXCLUSIVE;                       \
 221         else                                                            \
 222                 __wait.flags = 0;                                       \
 223                                                                         \
 224         for (;;) {                                                      \
 225                 long __int = prepare_to_wait_event(&wq, &__wait, state);\
 226                                                                         \
 227                 if (condition)                                          \
 228                         break;                                          \
 229                                                                         \
 230                 if (___wait_is_interruptible(state) && __int) {         \
 231                         __ret = __int;                                  \
 232                         if (exclusive) {                                \
 233                                 abort_exclusive_wait(&wq, &__wait,      \
 234                                                      state, NULL);      \
 235                                 goto __out;                             \
 236                         }                                               \
 237                         break;                                          \
 238                 }                                                       \
 239                                                                         \
 240                 cmd;                                                    \
 241         }                                                               \
 242         finish_wait(&wq, &__wait);                                      \
 243 __out:  __ret;                                                          \
 244 })
 245
 246 #define __wait_event(wq, condition)                                     \
 247         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 248                             schedule())
 249
 250 /**
 251  * wait_event - sleep until a condition gets true
 252  * @wq: the waitqueue to wait on
 253  * @condition: a C expression for the event to wait for
 254  *
 255  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 256  * @condition evaluates to true. The @condition is checked each time
 257  * the waitqueue @wq is woken up.
 258  *
 259  * wake_up() has to be called after changing any variable that could
 260  * change the result of the wait condition.
 261  */
 262 #define wait_event(wq, condition)                                       \
 263 do {                                                                    \
 264         might_sleep();                                                  \
 265         if (condition)                                                  \
 266                 break;                                                  \
 267         __wait_event(wq, condition);                                    \
 268 } while (0)
 269
 270 #define __wait_event_freezable(wq, condition)                           \
 271         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
 272                             schedule(); try_to_freeze())
 273
 274 /**
 275  * wait_event - sleep (or freeze) until a condition gets true
 276  * @wq: the waitqueue to wait on
 277  * @condition: a C expression for the event to wait for
 278  *
 279  * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
 280  * to system load) until the @condition evaluates to true. The
 281  * @condition is checked each time the waitqueue @wq is woken up.
 282  *
 283  * wake_up() has to be called after changing any variable that could
 284  * change the result of the wait condition.
 285  */
 286 #define wait_event_freezable(wq, condition)                             \
 287 ({                                                                      \
 288         int __ret = 0;                                                  \
 289         might_sleep();                                                  \
 290         if (!(condition))                                               \
 291                 __ret = __wait_event_freezable(wq, condition);          \
 292         __ret;                                                          \
 293 })
 294
 295 #define __wait_event_timeout(wq, condition, timeout)                    \
 296         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 297                       TASK_UNINTERRUPTIBLE, 0, timeout,                 \
 298                       __ret = schedule_timeout(__ret))
 299
 300 /**
 301  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 302  * @wq: the waitqueue to wait on
 303  * @condition: a C expression for the event to wait for
 304  * @timeout: timeout, in jiffies
 305  *
 306  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 307  * @condition evaluates to true. The @condition is checked each time
 308  * the waitqueue @wq is woken up.
 309  *
 310  * wake_up() has to be called after changing any variable that could
 311  * change the result of the wait condition.
 312  *
 313  * Returns:
 314  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 315  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 316  * or the remaining jiffies (at least 1) if the @condition evaluated
 317  * to %true before the @timeout elapsed.
 318  */
 319 #define wait_event_timeout(wq, condition, timeout)                      \
 320 ({                                                                      \
 321         long __ret = timeout;                                           \
 322         might_sleep();                                                  \
 323         if (!___wait_cond_timeout(condition))                           \
 324                 __ret = __wait_event_timeout(wq, condition, timeout);   \
 325         __ret;                                                          \
 326 })
 327
 328 #define __wait_event_freezable_timeout(wq, condition, timeout)          \
 329         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 330                       TASK_INTERRUPTIBLE, 0, timeout,                   \
 331                       __ret = schedule_timeout(__ret); try_to_freeze())
 332
 333 /*
 334  * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
 335  * increasing load and is freezable.
 336  */
 337 #define wait_event_freezable_timeout(wq, condition, timeout)            \
 338 ({                                                                      \
 339         long __ret = timeout;                                           \
 340         might_sleep();                                                  \
 341         if (!___wait_cond_timeout(condition))                           \
 342                 __ret = __wait_event_freezable_timeout(wq, condition, timeout); \
 343         __ret;                                                          \
 344 })
 345
 346 #define __wait_event_cmd(wq, condition, cmd1, cmd2)                     \
 347         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 348                             cmd1; schedule(); cmd2)
 349
 350 /**
 351  * wait_event_cmd - sleep until a condition gets true
 352  * @wq: the waitqueue to wait on
 353  * @condition: a C expression for the event to wait for
 354  * @cmd1: the command will be executed before sleep
 355  * @cmd2: the command will be executed after sleep
 356  *
 357  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 358  * @condition evaluates to true. The @condition is checked each time
 359  * the waitqueue @wq is woken up.
 360  *
 361  * wake_up() has to be called after changing any variable that could
 362  * change the result of the wait condition.
 363  */
 364 #define wait_event_cmd(wq, condition, cmd1, cmd2)                       \
 365 do {                                                                    \
 366         might_sleep();                                                  \
 367         if (condition)                                                  \
 368                 break;                                                  \
 369         __wait_event_cmd(wq, condition, cmd1, cmd2);                    \
 370 } while (0)
 371
 372 #define __wait_event_interruptible(wq, condition)                       \
 373         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
 374                       schedule())
 375
 376 /**
 377  * wait_event_interruptible - sleep until a condition gets true
 378  * @wq: the waitqueue to wait on
 379  * @condition: a C expression for the event to wait for
 380  *
 381  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 382  * @condition evaluates to true or a signal is received.
 383  * The @condition is checked each time the waitqueue @wq is woken up.
 384  *
 385  * wake_up() has to be called after changing any variable that could
 386  * change the result of the wait condition.
 387  *
 388  * The function will return -ERESTARTSYS if it was interrupted by a
 389  * signal and 0 if @condition evaluated to true.
 390  */
 391 #define wait_event_interruptible(wq, condition)                         \
 392 ({                                                                      \
 393         int __ret = 0;                                                  \
 394         might_sleep();                                                  \
 395         if (!(condition))                                               \
 396                 __ret = __wait_event_interruptible(wq, condition);      \
 397         __ret;                                                          \
 398 })
 399
 400 #define __wait_event_interruptible_timeout(wq, condition, timeout)      \
 401         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 402                       TASK_INTERRUPTIBLE, 0, timeout,                   \
 403                       __ret = schedule_timeout(__ret))
 404
 405 /**
 406  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 407  * @wq: the waitqueue to wait on
 408  * @condition: a C expression for the event to wait for
 409  * @timeout: timeout, in jiffies
 410  *
 411  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 412  * @condition evaluates to true or a signal is received.
 413  * The @condition is checked each time the waitqueue @wq is woken up.
 414  *
 415  * wake_up() has to be called after changing any variable that could
 416  * change the result of the wait condition.
 417  *
 418  * Returns:
 419  * 0 if the @condition evaluated to %false after the @timeout elapsed,
 420  * 1 if the @condition evaluated to %true after the @timeout elapsed,
 421  * the remaining jiffies (at least 1) if the @condition evaluated
 422  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
 423  * interrupted by a signal.
 424  */
 425 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
 426 ({                                                                      \
 427         long __ret = timeout;                                           \
 428         might_sleep();                                                  \
 429         if (!___wait_cond_timeout(condition))                           \
 430                 __ret = __wait_event_interruptible_timeout(wq,          \
 431                                                 condition, timeout);    \
 432         __ret;                                                          \
 433 })
 434
 435 #define __wait_event_hrtimeout(wq, condition, timeout, state)           \
 436 ({                                                                      \
 437         int __ret = 0;                                                  \
 438         struct hrtimer_sleeper __t;                                     \
 439                                                                         \
 440         hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,              \
 441                               HRTIMER_MODE_REL);                        \
 442         hrtimer_init_sleeper(&__t, current);                            \
 443         if ((timeout).tv64 != KTIME_MAX)                                \
 444                 hrtimer_start_range_ns(&__t.timer, timeout,             \
 445                                        current->timer_slack_ns,         \
 446                                        HRTIMER_MODE_REL);               \
 447                                                                         \
 448         __ret = ___wait_event(wq, condition, state, 0, 0,               \
 449                 if (!__t.task) {                                        \
 450                         __ret = -ETIME;                                 \
 451                         break;                                          \
 452                 }                                                       \
 453                 schedule());                                            \
 454                                                                         \
 455         hrtimer_cancel(&__t.timer);                                     \
 456         destroy_hrtimer_on_stack(&__t.timer);                           \
 457         __ret;                                                          \
 458 })
 459
 460 /**
 461  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
 462  * @wq: the waitqueue to wait on
 463  * @condition: a C expression for the event to wait for
 464  * @timeout: timeout, as a ktime_t
 465  *
 466  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 467  * @condition evaluates to true or a signal is received.
 468  * The @condition is checked each time the waitqueue @wq is woken up.
 469  *
 470  * wake_up() has to be called after changing any variable that could
 471  * change the result of the wait condition.
 472  *
 473  * The function returns 0 if @condition became true, or -ETIME if the timeout
 474  * elapsed.
 475  */
 476 #define wait_event_hrtimeout(wq, condition, timeout)                    \
 477 ({                                                                      \
 478         int __ret = 0;                                                  \
 479         might_sleep();                                                  \
 480         if (!(condition))                                               \
 481                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 482                                                TASK_UNINTERRUPTIBLE);   \
 483         __ret;                                                          \
 484 })
 485
 486 /**
 487  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
 488  * @wq: the waitqueue to wait on
 489  * @condition: a C expression for the event to wait for
 490  * @timeout: timeout, as a ktime_t
 491  *
 492  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 493  * @condition evaluates to true or a signal is received.
 494  * The @condition is checked each time the waitqueue @wq is woken up.
 495  *
 496  * wake_up() has to be called after changing any variable that could
 497  * change the result of the wait condition.
 498  *
 499  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
 500  * interrupted by a signal, or -ETIME if the timeout elapsed.
 501  */
 502 #define wait_event_interruptible_hrtimeout(wq, condition, timeout)      \
 503 ({                                                                      \
 504         long __ret = 0;                                                 \
 505         might_sleep();                                                  \
 506         if (!(condition))                                               \
 507                 __ret = __wait_event_hrtimeout(wq, condition, timeout,  \
 508                                                TASK_INTERRUPTIBLE);     \
 509         __ret;                                                          \
 510 })
 511
 512 #define __wait_event_interruptible_exclusive(wq, condition)             \
 513         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
 514                       schedule())
 515
 516 #define wait_event_interruptible_exclusive(wq, condition)               \
 517 ({                                                                      \
 518         int __ret = 0;                                                  \
 519         might_sleep();                                                  \
 520         if (!(condition))                                               \
 521                 __ret = __wait_event_interruptible_exclusive(wq, condition);\
 522         __ret;                                                          \
 523 })
 524
 525
 526 #define __wait_event_freezable_exclusive(wq, condition)                 \
 527         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,          \
 528                         schedule(); try_to_freeze())
 529
 530 #define wait_event_freezable_exclusive(wq, condition)                   \
 531 ({                                                                      \
 532         int __ret = 0;                                                  \
 533         might_sleep();                                                  \
 534         if (!(condition))                                               \
 535                 __ret = __wait_event_freezable_exclusive(wq, condition);\
 536         __ret;                                                          \
 537 })
 538
 539
 540 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
 541 ({                                                                      \
 542         int __ret = 0;                                                  \
 543         DEFINE_WAIT(__wait);                                            \
 544         if (exclusive)                                                  \
 545                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
 546         do {                                                            \
 547                 if (likely(list_empty(&__wait.task_list)))              \
 548                         __add_wait_queue_tail(&(wq), &__wait);          \
 549                 set_current_state(TASK_INTERRUPTIBLE);                  \
 550                 if (signal_pending(current)) {                          \
 551                         __ret = -ERESTARTSYS;                           \
 552                         break;                                          \
 553                 }                                                       \
 554                 if (irq)                                                \
 555                         spin_unlock_irq(&(wq).lock);                    \
 556                 else                                                    \
 557                         spin_unlock(&(wq).lock);                        \
 558                 schedule();                                             \
 559                 if (irq)                                                \
 560                         spin_lock_irq(&(wq).lock);                      \
 561                 else                                                    \
 562                         spin_lock(&(wq).lock);                          \
 563         } while (!(condition));                                         \
 564         __remove_wait_queue(&(wq), &__wait);                            \
 565         __set_current_state(TASK_RUNNING);                              \
 566         __ret;                                                          \
 567 })
 568
 569
 570 /**
 571  * wait_event_interruptible_locked - sleep until a condition gets true
 572  * @wq: the waitqueue to wait on
 573  * @condition: a C expression for the event to wait for
 574  *
 575  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 576  * @condition evaluates to true or a signal is received.
 577  * The @condition is checked each time the waitqueue @wq is woken up.
 578  *
 579  * It must be called with wq.lock being held.  This spinlock is
 580  * unlocked while sleeping but @condition testing is done while lock
 581  * is held and when this macro exits the lock is held.
 582  *
 583  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 584  * functions which must match the way they are locked/unlocked outside
 585  * of this macro.
 586  *
 587  * wake_up_locked() has to be called after changing any variable that could
 588  * change the result of the wait condition.
 589  *
 590  * The function will return -ERESTARTSYS if it was interrupted by a
 591  * signal and 0 if @condition evaluated to true.
 592  */
 593 #define wait_event_interruptible_locked(wq, condition)                  \
 594         ((condition)                                                    \
 595          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
 596
 597 /**
 598  * wait_event_interruptible_locked_irq - sleep until a condition gets true
 599  * @wq: the waitqueue to wait on
 600  * @condition: a C expression for the event to wait for
 601  *
 602  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 603  * @condition evaluates to true or a signal is received.
 604  * The @condition is checked each time the waitqueue @wq is woken up.
 605  *
 606  * It must be called with wq.lock being held.  This spinlock is
 607  * unlocked while sleeping but @condition testing is done while lock
 608  * is held and when this macro exits the lock is held.
 609  *
 610  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 611  * functions which must match the way they are locked/unlocked outside
 612  * of this macro.
 613  *
 614  * wake_up_locked() has to be called after changing any variable that could
 615  * change the result of the wait condition.
 616  *
 617  * The function will return -ERESTARTSYS if it was interrupted by a
 618  * signal and 0 if @condition evaluated to true.
 619  */
 620 #define wait_event_interruptible_locked_irq(wq, condition)              \
 621         ((condition)                                                    \
 622          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
 623
 624 /**
 625  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
 626  * @wq: the waitqueue to wait on
 627  * @condition: a C expression for the event to wait for
 628  *
 629  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 630  * @condition evaluates to true or a signal is received.
 631  * The @condition is checked each time the waitqueue @wq is woken up.
 632  *
 633  * It must be called with wq.lock being held.  This spinlock is
 634  * unlocked while sleeping but @condition testing is done while lock
 635  * is held and when this macro exits the lock is held.
 636  *
 637  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 638  * functions which must match the way they are locked/unlocked outside
 639  * of this macro.
 640  *
 641  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 642  * set thus when other process waits process on the list if this
 643  * process is awaken further processes are not considered.
 644  *
 645  * wake_up_locked() has to be called after changing any variable that could
 646  * change the result of the wait condition.
 647  *
 648  * The function will return -ERESTARTSYS if it was interrupted by a
 649  * signal and 0 if @condition evaluated to true.
 650  */
 651 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
 652         ((condition)                                                    \
 653          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
 654
 655 /**
 656  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
 657  * @wq: the waitqueue to wait on
 658  * @condition: a C expression for the event to wait for
 659  *
 660  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 661  * @condition evaluates to true or a signal is received.
 662  * The @condition is checked each time the waitqueue @wq is woken up.
 663  *
 664  * It must be called with wq.lock being held.  This spinlock is
 665  * unlocked while sleeping but @condition testing is done while lock
 666  * is held and when this macro exits the lock is held.
 667  *
 668  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 669  * functions which must match the way they are locked/unlocked outside
 670  * of this macro.
 671  *
 672  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 673  * set thus when other process waits process on the list if this
 674  * process is awaken further processes are not considered.
 675  *
 676  * wake_up_locked() has to be called after changing any variable that could
 677  * change the result of the wait condition.
 678  *
 679  * The function will return -ERESTARTSYS if it was interrupted by a
 680  * signal and 0 if @condition evaluated to true.
 681  */
 682 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
 683         ((condition)                                                    \
 684          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
 685
 686
 687 #define __wait_event_killable(wq, condition)                            \
 688         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
 689
 690 /**
 691  * wait_event_killable - sleep until a condition gets true
 692  * @wq: the waitqueue to wait on
 693  * @condition: a C expression for the event to wait for
 694  *
 695  * The process is put to sleep (TASK_KILLABLE) until the
 696  * @condition evaluates to true or a signal is received.
 697  * The @condition is checked each time the waitqueue @wq is woken up.
 698  *
 699  * wake_up() has to be called after changing any variable that could
 700  * change the result of the wait condition.
 701  *
 702  * The function will return -ERESTARTSYS if it was interrupted by a
 703  * signal and 0 if @condition evaluated to true.
 704  */
 705 #define wait_event_killable(wq, condition)                              \
 706 ({                                                                      \
 707         int __ret = 0;                                                  \
 708         might_sleep();                                                  \
 709         if (!(condition))                                               \
 710                 __ret = __wait_event_killable(wq, condition);           \
 711         __ret;                                                          \
 712 })
 713
 714
 715 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 716         (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0,  \
 717                             spin_unlock_irq(&lock);                     \
 718                             cmd;                                        \
 719                             schedule();                                 \
 720                             spin_lock_irq(&lock))
 721
 722 /**
 723  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
 724  *                           condition is checked under the lock. This
 725  *                           is expected to be called with the lock
 726  *                           taken.
 727  * @wq: the waitqueue to wait on
 728  * @condition: a C expression for the event to wait for
 729  * @lock: a locked spinlock_t, which will be released before cmd
 730  *        and schedule() and reacquired afterwards.
 731  * @cmd: a command which is invoked outside the critical section before
 732  *       sleep
 733  *
 734  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 735  * @condition evaluates to true. The @condition is checked each time
 736  * the waitqueue @wq is woken up.
 737  *
 738  * wake_up() has to be called after changing any variable that could
 739  * change the result of the wait condition.
 740  *
 741  * This is supposed to be called while holding the lock. The lock is
 742  * dropped before invoking the cmd and going to sleep and is reacquired
 743  * afterwards.
 744  */
 745 #define wait_event_lock_irq_cmd(wq, condition, lock, cmd)               \
 746 do {                                                                    \
 747         if (condition)                                                  \
 748                 break;                                                  \
 749         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 750 } while (0)
 751
 752 /**
 753  * wait_event_lock_irq - sleep until a condition gets true. The
 754  *                       condition is checked under the lock. This
 755  *                       is expected to be called with the lock
 756  *                       taken.
 757  * @wq: the waitqueue to wait on
 758  * @condition: a C expression for the event to wait for
 759  * @lock: a locked spinlock_t, which will be released before schedule()
 760  *        and reacquired afterwards.
 761  *
 762  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 763  * @condition evaluates to true. The @condition is checked each time
 764  * the waitqueue @wq is woken up.
 765  *
 766  * wake_up() has to be called after changing any variable that could
 767  * change the result of the wait condition.
 768  *
 769  * This is supposed to be called while holding the lock. The lock is
 770  * dropped before going to sleep and is reacquired afterwards.
 771  */
 772 #define wait_event_lock_irq(wq, condition, lock)                        \
 773 do {                                                                    \
 774         if (condition)                                                  \
 775                 break;                                                  \
 776         __wait_event_lock_irq(wq, condition, lock, );                   \
 777 } while (0)
 778
 779
 780 #define __wait_event_interruptible_lock_irq(wq, condition, lock, cmd)   \
 781         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,          \
 782                       spin_unlock_irq(&lock);                           \
 783                       cmd;                                              \
 784                       schedule();                                       \
 785                       spin_lock_irq(&lock))
 786
 787 /**
 788  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
 789  *              The condition is checked under the lock. This is expected to
 790  *              be called with the lock taken.
 791  * @wq: the waitqueue to wait on
 792  * @condition: a C expression for the event to wait for
 793  * @lock: a locked spinlock_t, which will be released before cmd and
 794  *        schedule() and reacquired afterwards.
 795  * @cmd: a command which is invoked outside the critical section before
 796  *       sleep
 797  *
 798  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 799  * @condition evaluates to true or a signal is received. The @condition is
 800  * checked each time the waitqueue @wq is woken up.
 801  *
 802  * wake_up() has to be called after changing any variable that could
 803  * change the result of the wait condition.
 804  *
 805  * This is supposed to be called while holding the lock. The lock is
 806  * dropped before invoking the cmd and going to sleep and is reacquired
 807  * afterwards.
 808  *
 809  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 810  * and 0 if @condition evaluated to true.
 811  */
 812 #define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
 813 ({                                                                      \
 814         int __ret = 0;                                                  \
 815         if (!(condition))                                               \
 816                 __ret = __wait_event_interruptible_lock_irq(wq,         \
 817                                                 condition, lock, cmd);  \
 818         __ret;                                                          \
 819 })
 820
 821 /**
 822  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
 823  *              The condition is checked under the lock. This is expected
 824  *              to be called with the lock taken.
 825  * @wq: the waitqueue to wait on
 826  * @condition: a C expression for the event to wait for
 827  * @lock: a locked spinlock_t, which will be released before schedule()
 828  *        and reacquired afterwards.
 829  *
 830  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 831  * @condition evaluates to true or signal is received. The @condition is
 832  * checked each time the waitqueue @wq is woken up.
 833  *
 834  * wake_up() has to be called after changing any variable that could
 835  * change the result of the wait condition.
 836  *
 837  * This is supposed to be called while holding the lock. The lock is
 838  * dropped before going to sleep and is reacquired afterwards.
 839  *
 840  * The macro will return -ERESTARTSYS if it was interrupted by a signal
 841  * and 0 if @condition evaluated to true.
 842  */
 843 #define wait_event_interruptible_lock_irq(wq, condition, lock)          \
 844 ({                                                                      \
 845         int __ret = 0;                                                  \
 846         if (!(condition))                                               \
 847                 __ret = __wait_event_interruptible_lock_irq(wq,         \
 848                                                 condition, lock,);      \
 849         __ret;                                                          \
 850 })
 851
 852 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
 853                                                     lock, timeout)      \
 854         ___wait_event(wq, ___wait_cond_timeout(condition),              \
 855                       TASK_INTERRUPTIBLE, 0, timeout,                   \
 856                       spin_unlock_irq(&lock);                           \
 857                       __ret = schedule_timeout(__ret);                  \
 858                       spin_lock_irq(&lock));
 859
 860 /**
 861  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
 862  *              true or a timeout elapses. The condition is checked under
 863  *              the lock. This is expected to be called with the lock taken.
 864  * @wq: the waitqueue to wait on
 865  * @condition: a C expression for the event to wait for
 866  * @lock: a locked spinlock_t, which will be released before schedule()
 867  *        and reacquired afterwards.
 868  * @timeout: timeout, in jiffies
 869  *
 870  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 871  * @condition evaluates to true or signal is received. The @condition is
 872  * checked each time the waitqueue @wq is woken up.
 873  *
 874  * wake_up() has to be called after changing any variable that could
 875  * change the result of the wait condition.
 876  *
 877  * This is supposed to be called while holding the lock. The lock is
 878  * dropped before going to sleep and is reacquired afterwards.
 879  *
 880  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
 881  * was interrupted by a signal, and the remaining jiffies otherwise
 882  * if the condition evaluated to true before the timeout elapsed.
 883  */
 884 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
 885                                                   timeout)              \
 886 ({                                                                      \
 887         long __ret = timeout;                                           \
 888         if (!___wait_cond_timeout(condition))                           \
 889                 __ret = __wait_event_interruptible_lock_irq_timeout(    \
 890                                         wq, condition, lock, timeout);  \
 891         __ret;                                                          \
 892 })
 893
 894 /*
 895  * Waitqueues which are removed from the waitqueue_head at wakeup time
 896  */
 897 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
 898 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
 899 long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state);
 900 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
 901 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key);
 902 long wait_woken(wait_queue_t *wait, unsigned mode, long timeout);
 903 int woken_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 904 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 905 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 906
 907 #define DEFINE_WAIT_FUNC(name, function)                                \
 908         wait_queue_t name = {                                           \
 909                 .private        = current,                              \
 910                 .func           = function,                             \
 911                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
 912         }
 913
 914 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
 915
 916 #define DEFINE_WAIT_BIT(name, word, bit)                                \
 917         struct wait_bit_queue name = {                                  \
 918                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
 919                 .wait   = {                                             \
 920                         .private        = current,                      \
 921                         .func           = wake_bit_function,            \
 922                         .task_list      =                               \
 923                                 LIST_HEAD_INIT((name).wait.task_list),  \
 924                 },                                                      \
 925         }
 926
 927 #define init_wait(wait)                                                 \
 928         do {                                                            \
 929                 (wait)->private = current;                              \
 930                 (wait)->func = autoremove_wake_function;                \
 931                 INIT_LIST_HEAD(&(wait)->task_list);                     \
 932                 (wait)->flags = 0;                                      \
 933         } while (0)
 934
 935
 936 extern int bit_wait(struct wait_bit_key *);
 937 extern int bit_wait_io(struct wait_bit_key *);
 938 extern int bit_wait_timeout(struct wait_bit_key *);
 939 extern int bit_wait_io_timeout(struct wait_bit_key *);
 940
 941 /**
 942  * wait_on_bit - wait for a bit to be cleared
 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  * For instance, if one were to have waiters on a bitflag, one would
 950  * call wait_on_bit() in threads waiting for the bit to clear.
 951  * One uses wait_on_bit() where one is waiting for the bit to clear,
 952  * but has no intention of setting it.
 953  * Returned value will be zero if the bit was cleared, or non-zero
 954  * if the process received a signal and the mode permitted wakeup
 955  * on that signal.
 956  */
 957 static inline int
 958 wait_on_bit(void *word, int bit, unsigned mode)
 959 {
 960         might_sleep();
 961         if (!test_bit(bit, word))
 962                 return 0;
 963         return out_of_line_wait_on_bit(word, bit,
 964                                        bit_wait,
 965                                        mode);
 966 }
 967
 968 /**
 969  * wait_on_bit_io - wait for a bit to be cleared
 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.  This is similar to wait_on_bit(), but calls
 976  * io_schedule() instead of schedule() for the actual waiting.
 977  *
 978  * Returned value will be zero if the bit was cleared, or non-zero
 979  * if the process received a signal and the mode permitted wakeup
 980  * on that signal.
 981  */
 982 static inline int
 983 wait_on_bit_io(void *word, int bit, unsigned mode)
 984 {
 985         might_sleep();
 986         if (!test_bit(bit, word))
 987                 return 0;
 988         return out_of_line_wait_on_bit(word, bit,
 989                                        bit_wait_io,
 990                                        mode);
 991 }
 992
 993 /**
 994  * wait_on_bit_action - wait for a bit to be cleared
 995  * @word: the word being waited on, a kernel virtual address
 996  * @bit: the bit of the word being waited on
 997  * @action: the function used to sleep, which may take special actions
 998  * @mode: the task state to sleep in
 999  *
1000  * Use the standard hashed waitqueue table to wait for a bit
1001  * to be cleared, and allow the waiting action to be specified.
1002  * This is like wait_on_bit() but allows fine control of how the waiting
1003  * is done.
1004  *
1005  * Returned value will be zero if the bit was cleared, or non-zero
1006  * if the process received a signal and the mode permitted wakeup
1007  * on that signal.
1008  */
1009 static inline int
1010 wait_on_bit_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
1011 {
1012         might_sleep();
1013         if (!test_bit(bit, word))
1014                 return 0;
1015         return out_of_line_wait_on_bit(word, bit, action, mode);
1016 }
1017
1018 /**
1019  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
1020  * @word: the word being waited on, a kernel virtual address
1021  * @bit: the bit of the word being waited on
1022  * @mode: the task state to sleep in
1023  *
1024  * There is a standard hashed waitqueue table for generic use. This
1025  * is the part of the hashtable's accessor API that waits on a bit
1026  * when one intends to set it, for instance, trying to lock bitflags.
1027  * For instance, if one were to have waiters trying to set bitflag
1028  * and waiting for it to clear before setting it, one would call
1029  * wait_on_bit() in threads waiting to be able to set the bit.
1030  * One uses wait_on_bit_lock() where one is waiting for the bit to
1031  * clear with the intention of setting it, and when done, clearing it.
1032  *
1033  * Returns zero if the bit was (eventually) found to be clear and was
1034  * set.  Returns non-zero if a signal was delivered to the process and
1035  * the @mode allows that signal to wake the process.
1036  */
1037 static inline int
1038 wait_on_bit_lock(void *word, int bit, unsigned mode)
1039 {
1040         might_sleep();
1041         if (!test_and_set_bit(bit, word))
1042                 return 0;
1043         return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode);
1044 }
1045
1046 /**
1047  * wait_on_bit_lock_io - wait for a bit to be cleared, when wanting to set it
1048  * @word: the word being waited on, a kernel virtual address
1049  * @bit: the bit of the word being waited on
1050  * @mode: the task state to sleep in
1051  *
1052  * Use the standard hashed waitqueue table to wait for a bit
1053  * to be cleared and then to atomically set it.  This is similar
1054  * to wait_on_bit(), but calls io_schedule() instead of schedule()
1055  * for the actual waiting.
1056  *
1057  * Returns zero if the bit was (eventually) found to be clear and was
1058  * set.  Returns non-zero if a signal was delivered to the process and
1059  * the @mode allows that signal to wake the process.
1060  */
1061 static inline int
1062 wait_on_bit_lock_io(void *word, int bit, unsigned mode)
1063 {
1064         might_sleep();
1065         if (!test_and_set_bit(bit, word))
1066                 return 0;
1067         return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode);
1068 }
1069
1070 /**
1071  * wait_on_bit_lock_action - wait for a bit to be cleared, when wanting to set it
1072  * @word: the word being waited on, a kernel virtual address
1073  * @bit: the bit of the word being waited on
1074  * @action: the function used to sleep, which may take special actions
1075  * @mode: the task state to sleep in
1076  *
1077  * Use the standard hashed waitqueue table to wait for a bit
1078  * to be cleared and then to set it, and allow the waiting action
1079  * to be specified.
1080  * This is like wait_on_bit() but allows fine control of how the waiting
1081  * is done.
1082  *
1083  * Returns zero if the bit was (eventually) found to be clear and was
1084  * set.  Returns non-zero if a signal was delivered to the process and
1085  * the @mode allows that signal to wake the process.
1086  */
1087 static inline int
1088 wait_on_bit_lock_action(void *word, int bit, wait_bit_action_f *action, unsigned mode)
1089 {
1090         might_sleep();
1091         if (!test_and_set_bit(bit, word))
1092                 return 0;
1093         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
1094 }
1095
1096 /**
1097  * wait_on_atomic_t - Wait for an atomic_t to become 0
1098  * @val: The atomic value being waited on, a kernel virtual address
1099  * @action: the function used to sleep, which may take special actions
1100  * @mode: the task state to sleep in
1101  *
1102  * Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
1103  * the purpose of getting a waitqueue, but we set the key to a bit number
1104  * outside of the target 'word'.
1105  */
1106 static inline
1107 int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
1108 {
1109         might_sleep();
1110         if (atomic_read(val) == 0)
1111                 return 0;
1112         return out_of_line_wait_on_atomic_t(val, action, mode);
1113 }
1114
1115 #endif /* _LINUX_WAIT_H */