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   1 #ifndef _LINUX_WAIT_H
   2 #define _LINUX_WAIT_H
   3
   4 #define WNOHANG         0x00000001
   5 #define WUNTRACED       0x00000002
   6 #define WSTOPPED        WUNTRACED
   7 #define WEXITED         0x00000004
   8 #define WCONTINUED      0x00000008
   9 #define WNOWAIT         0x01000000      /* Don't reap, just poll status.  */
  10
  11 #define __WNOTHREAD     0x20000000      /* Don't wait on children of other threads in this group */
  12 #define __WALL          0x40000000      /* Wait on all children, regardless of type */
  13 #define __WCLONE        0x80000000      /* Wait only on non-SIGCHLD children */
  14
  15 /* First argument to waitid: */
  16 #define P_ALL           0
  17 #define P_PID           1
  18 #define P_PGID          2
  19
  20 #ifdef __KERNEL__
  21
  22 #include <linux/list.h>
  23 #include <linux/stddef.h>
  24 #include <linux/spinlock.h>
  25 #include <asm/system.h>
  26 #include <asm/current.h>
  27
  28 typedef struct __wait_queue wait_queue_t;
  29 typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int sync, void *key);
  30 int default_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
  31
  32 struct __wait_queue {
  33         unsigned int flags;
  34 #define WQ_FLAG_EXCLUSIVE       0x01
  35         void *private;
  36         wait_queue_func_t func;
  37         struct list_head task_list;
  38 };
  39
  40 struct wait_bit_key {
  41         void *flags;
  42         int bit_nr;
  43 };
  44
  45 struct wait_bit_queue {
  46         struct wait_bit_key key;
  47         wait_queue_t wait;
  48 };
  49
  50 struct __wait_queue_head {
  51         spinlock_t lock;
  52         struct list_head task_list;
  53 };
  54 typedef struct __wait_queue_head wait_queue_head_t;
  55
  56 struct task_struct;
  57
  58 /*
  59  * Macros for declaration and initialisaton of the datatypes
  60  */
  61
  62 #define __WAITQUEUE_INITIALIZER(name, tsk) {                            \
  63         .private        = tsk,                                          \
  64         .func           = default_wake_function,                        \
  65         .task_list      = { NULL, NULL } }
  66
  67 #define DECLARE_WAITQUEUE(name, tsk)                                    \
  68         wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
  69
  70 #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                           \
  71         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),              \
  72         .task_list      = { &(name).task_list, &(name).task_list } }
  73
  74 #define DECLARE_WAIT_QUEUE_HEAD(name) \
  75         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
  76
  77 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)                           \
  78         { .flags = word, .bit_nr = bit, }
  79
  80 extern void init_waitqueue_head(wait_queue_head_t *q);
  81
  82 #ifdef CONFIG_LOCKDEP
  83 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
  84         ({ init_waitqueue_head(&name); name; })
  85 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
  86         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
  87 #else
  88 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
  89 #endif
  90
  91 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
  92 {
  93         q->flags = 0;
  94         q->private = p;
  95         q->func = default_wake_function;
  96 }
  97
  98 static inline void init_waitqueue_func_entry(wait_queue_t *q,
  99                                         wait_queue_func_t func)
 100 {
 101         q->flags = 0;
 102         q->private = NULL;
 103         q->func = func;
 104 }
 105
 106 static inline int waitqueue_active(wait_queue_head_t *q)
 107 {
 108         return !list_empty(&q->task_list);
 109 }
 110
 111 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 112 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
 113 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 114
 115 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
 116 {
 117         list_add(&new->task_list, &head->task_list);
 118 }
 119
 120 /*
 121  * Used for wake-one threads:
 122  */
 123 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
 124                                                 wait_queue_t *new)
 125 {
 126         list_add_tail(&new->task_list, &head->task_list);
 127 }
 128
 129 static inline void __remove_wait_queue(wait_queue_head_t *head,
 130                                                         wait_queue_t *old)
 131 {
 132         list_del(&old->task_list);
 133 }
 134
 135 void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
 136                         int nr_exclusive, int sync, void *key);
 137 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 138 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
 139 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr,
 140                         void *key);
 141 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode);
 142 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
 143 void __wake_up_bit(wait_queue_head_t *, void *, int);
 144 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
 145 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
 146 void wake_up_bit(void *, int);
 147 int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned);
 148 int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned);
 149 wait_queue_head_t *bit_waitqueue(void *, int);
 150
 151 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
 152 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
 153 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
 154 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL)
 155
 156 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 157 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
 158 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
 159 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
 160
 161 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 162 /*
 163  * macro to avoid include hell
 164  */
 165 #define wake_up_nested(x, s)                                            \
 166 do {                                                                    \
 167         unsigned long flags;                                            \
 168                                                                         \
 169         spin_lock_irqsave_nested(&(x)->lock, flags, (s));               \
 170         wake_up_locked(x);                                              \
 171         spin_unlock_irqrestore(&(x)->lock, flags);                      \
 172 } while (0)
 173 #else
 174 #define wake_up_nested(x, s)            wake_up(x)
 175 #endif
 176
 177 #define __wait_event(wq, condition)                                     \
 178 do {                                                                    \
 179         DEFINE_WAIT(__wait);                                            \
 180                                                                         \
 181         for (;;) {                                                      \
 182                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 183                 if (condition)                                          \
 184                         break;                                          \
 185                 schedule();                                             \
 186         }                                                               \
 187         finish_wait(&wq, &__wait);                                      \
 188 } while (0)
 189
 190 /**
 191  * wait_event - sleep until a condition gets true
 192  * @wq: the waitqueue to wait on
 193  * @condition: a C expression for the event to wait for
 194  *
 195  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 196  * @condition evaluates to true. The @condition is checked each time
 197  * the waitqueue @wq is woken up.
 198  *
 199  * wake_up() has to be called after changing any variable that could
 200  * change the result of the wait condition.
 201  */
 202 #define wait_event(wq, condition)                                       \
 203 do {                                                                    \
 204         if (condition)                                                  \
 205                 break;                                                  \
 206         __wait_event(wq, condition);                                    \
 207 } while (0)
 208
 209 #define __wait_event_timeout(wq, condition, ret)                        \
 210 do {                                                                    \
 211         DEFINE_WAIT(__wait);                                            \
 212                                                                         \
 213         for (;;) {                                                      \
 214                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 215                 if (condition)                                          \
 216                         break;                                          \
 217                 ret = schedule_timeout(ret);                            \
 218                 if (!ret)                                               \
 219                         break;                                          \
 220         }                                                               \
 221         finish_wait(&wq, &__wait);                                      \
 222 } while (0)
 223
 224 /**
 225  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 226  * @wq: the waitqueue to wait on
 227  * @condition: a C expression for the event to wait for
 228  * @timeout: timeout, in jiffies
 229  *
 230  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 231  * @condition evaluates to true. The @condition is checked each time
 232  * the waitqueue @wq is woken up.
 233  *
 234  * wake_up() has to be called after changing any variable that could
 235  * change the result of the wait condition.
 236  *
 237  * The function returns 0 if the @timeout elapsed, and the remaining
 238  * jiffies if the condition evaluated to true before the timeout elapsed.
 239  */
 240 #define wait_event_timeout(wq, condition, timeout)                      \
 241 ({                                                                      \
 242         long __ret = timeout;                                           \
 243         if (!(condition))                                               \
 244                 __wait_event_timeout(wq, condition, __ret);             \
 245         __ret;                                                          \
 246 })
 247
 248 #define __wait_event_interruptible(wq, condition, ret)                  \
 249 do {                                                                    \
 250         DEFINE_WAIT(__wait);                                            \
 251                                                                         \
 252         for (;;) {                                                      \
 253                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 254                 if (condition)                                          \
 255                         break;                                          \
 256                 if (!signal_pending(current)) {                         \
 257                         schedule();                                     \
 258                         continue;                                       \
 259                 }                                                       \
 260                 ret = -ERESTARTSYS;                                     \
 261                 break;                                                  \
 262         }                                                               \
 263         finish_wait(&wq, &__wait);                                      \
 264 } while (0)
 265
 266 /**
 267  * wait_event_interruptible - sleep until a condition gets true
 268  * @wq: the waitqueue to wait on
 269  * @condition: a C expression for the event to wait for
 270  *
 271  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 272  * @condition evaluates to true or a signal is received.
 273  * The @condition is checked each time the waitqueue @wq is woken up.
 274  *
 275  * wake_up() has to be called after changing any variable that could
 276  * change the result of the wait condition.
 277  *
 278  * The function will return -ERESTARTSYS if it was interrupted by a
 279  * signal and 0 if @condition evaluated to true.
 280  */
 281 #define wait_event_interruptible(wq, condition)                         \
 282 ({                                                                      \
 283         int __ret = 0;                                                  \
 284         if (!(condition))                                               \
 285                 __wait_event_interruptible(wq, condition, __ret);       \
 286         __ret;                                                          \
 287 })
 288
 289 #define __wait_event_interruptible_timeout(wq, condition, ret)          \
 290 do {                                                                    \
 291         DEFINE_WAIT(__wait);                                            \
 292                                                                         \
 293         for (;;) {                                                      \
 294                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 295                 if (condition)                                          \
 296                         break;                                          \
 297                 if (!signal_pending(current)) {                         \
 298                         ret = schedule_timeout(ret);                    \
 299                         if (!ret)                                       \
 300                                 break;                                  \
 301                         continue;                                       \
 302                 }                                                       \
 303                 ret = -ERESTARTSYS;                                     \
 304                 break;                                                  \
 305         }                                                               \
 306         finish_wait(&wq, &__wait);                                      \
 307 } while (0)
 308
 309 /**
 310  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 311  * @wq: the waitqueue to wait on
 312  * @condition: a C expression for the event to wait for
 313  * @timeout: timeout, in jiffies
 314  *
 315  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 316  * @condition evaluates to true or a signal is received.
 317  * The @condition is checked each time the waitqueue @wq is woken up.
 318  *
 319  * wake_up() has to be called after changing any variable that could
 320  * change the result of the wait condition.
 321  *
 322  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
 323  * was interrupted by a signal, and the remaining jiffies otherwise
 324  * if the condition evaluated to true before the timeout elapsed.
 325  */
 326 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
 327 ({                                                                      \
 328         long __ret = timeout;                                           \
 329         if (!(condition))                                               \
 330                 __wait_event_interruptible_timeout(wq, condition, __ret); \
 331         __ret;                                                          \
 332 })
 333
 334 #define __wait_event_interruptible_exclusive(wq, condition, ret)        \
 335 do {                                                                    \
 336         DEFINE_WAIT(__wait);                                            \
 337                                                                         \
 338         for (;;) {                                                      \
 339                 prepare_to_wait_exclusive(&wq, &__wait,                 \
 340                                         TASK_INTERRUPTIBLE);            \
 341                 if (condition) {                                        \
 342                         finish_wait(&wq, &__wait);                      \
 343                         break;                                          \
 344                 }                                                       \
 345                 if (!signal_pending(current)) {                         \
 346                         schedule();                                     \
 347                         continue;                                       \
 348                 }                                                       \
 349                 ret = -ERESTARTSYS;                                     \
 350                 abort_exclusive_wait(&wq, &__wait,                      \
 351                                 TASK_INTERRUPTIBLE, NULL);              \
 352                 break;                                                  \
 353         }                                                               \
 354 } while (0)
 355
 356 #define wait_event_interruptible_exclusive(wq, condition)               \
 357 ({                                                                      \
 358         int __ret = 0;                                                  \
 359         if (!(condition))                                               \
 360                 __wait_event_interruptible_exclusive(wq, condition, __ret);\
 361         __ret;                                                          \
 362 })
 363
 364 #define __wait_event_killable(wq, condition, ret)                       \
 365 do {                                                                    \
 366         DEFINE_WAIT(__wait);                                            \
 367                                                                         \
 368         for (;;) {                                                      \
 369                 prepare_to_wait(&wq, &__wait, TASK_KILLABLE);           \
 370                 if (condition)                                          \
 371                         break;                                          \
 372                 if (!fatal_signal_pending(current)) {                   \
 373                         schedule();                                     \
 374                         continue;                                       \
 375                 }                                                       \
 376                 ret = -ERESTARTSYS;                                     \
 377                 break;                                                  \
 378         }                                                               \
 379         finish_wait(&wq, &__wait);                                      \
 380 } while (0)
 381
 382 /**
 383  * wait_event_killable - sleep until a condition gets true
 384  * @wq: the waitqueue to wait on
 385  * @condition: a C expression for the event to wait for
 386  *
 387  * The process is put to sleep (TASK_KILLABLE) until the
 388  * @condition evaluates to true or a signal is received.
 389  * The @condition is checked each time the waitqueue @wq is woken up.
 390  *
 391  * wake_up() has to be called after changing any variable that could
 392  * change the result of the wait condition.
 393  *
 394  * The function will return -ERESTARTSYS if it was interrupted by a
 395  * signal and 0 if @condition evaluated to true.
 396  */
 397 #define wait_event_killable(wq, condition)                              \
 398 ({                                                                      \
 399         int __ret = 0;                                                  \
 400         if (!(condition))                                               \
 401                 __wait_event_killable(wq, condition, __ret);            \
 402         __ret;                                                          \
 403 })
 404
 405 /*
 406  * Must be called with the spinlock in the wait_queue_head_t held.
 407  */
 408 static inline void add_wait_queue_exclusive_locked(wait_queue_head_t *q,
 409                                                    wait_queue_t * wait)
 410 {
 411         wait->flags |= WQ_FLAG_EXCLUSIVE;
 412         __add_wait_queue_tail(q,  wait);
 413 }
 414
 415 /*
 416  * Must be called with the spinlock in the wait_queue_head_t held.
 417  */
 418 static inline void remove_wait_queue_locked(wait_queue_head_t *q,
 419                                             wait_queue_t * wait)
 420 {
 421         __remove_wait_queue(q,  wait);
 422 }
 423
 424 /*
 425  * These are the old interfaces to sleep waiting for an event.
 426  * They are racy.  DO NOT use them, use the wait_event* interfaces above.
 427  * We plan to remove these interfaces.
 428  */
 429 extern void sleep_on(wait_queue_head_t *q);
 430 extern long sleep_on_timeout(wait_queue_head_t *q,
 431                                       signed long timeout);
 432 extern void interruptible_sleep_on(wait_queue_head_t *q);
 433 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
 434                                            signed long timeout);
 435
 436 /*
 437  * Waitqueues which are removed from the waitqueue_head at wakeup time
 438  */
 439 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
 440 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
 441 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
 442 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
 443                         unsigned int mode, void *key);
 444 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 445 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 446
 447 #define DEFINE_WAIT(name)                                               \
 448         wait_queue_t name = {                                           \
 449                 .private        = current,                              \
 450                 .func           = autoremove_wake_function,             \
 451                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
 452         }
 453
 454 #define DEFINE_WAIT_BIT(name, word, bit)                                \
 455         struct wait_bit_queue name = {                                  \
 456                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
 457                 .wait   = {                                             \
 458                         .private        = current,                      \
 459                         .func           = wake_bit_function,            \
 460                         .task_list      =                               \
 461                                 LIST_HEAD_INIT((name).wait.task_list),  \
 462                 },                                                      \
 463         }
 464
 465 #define init_wait(wait)                                                 \
 466         do {                                                            \
 467                 (wait)->private = current;                              \
 468                 (wait)->func = autoremove_wake_function;                \
 469                 INIT_LIST_HEAD(&(wait)->task_list);                     \
 470         } while (0)
 471
 472 /**
 473  * wait_on_bit - wait for a bit to be cleared
 474  * @word: the word being waited on, a kernel virtual address
 475  * @bit: the bit of the word being waited on
 476  * @action: the function used to sleep, which may take special actions
 477  * @mode: the task state to sleep in
 478  *
 479  * There is a standard hashed waitqueue table for generic use. This
 480  * is the part of the hashtable's accessor API that waits on a bit.
 481  * For instance, if one were to have waiters on a bitflag, one would
 482  * call wait_on_bit() in threads waiting for the bit to clear.
 483  * One uses wait_on_bit() where one is waiting for the bit to clear,
 484  * but has no intention of setting it.
 485  */
 486 static inline int wait_on_bit(void *word, int bit,
 487                                 int (*action)(void *), unsigned mode)
 488 {
 489         if (!test_bit(bit, word))
 490                 return 0;
 491         return out_of_line_wait_on_bit(word, bit, action, mode);
 492 }
 493
 494 /**
 495  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
 496  * @word: the word being waited on, a kernel virtual address
 497  * @bit: the bit of the word being waited on
 498  * @action: the function used to sleep, which may take special actions
 499  * @mode: the task state to sleep in
 500  *
 501  * There is a standard hashed waitqueue table for generic use. This
 502  * is the part of the hashtable's accessor API that waits on a bit
 503  * when one intends to set it, for instance, trying to lock bitflags.
 504  * For instance, if one were to have waiters trying to set bitflag
 505  * and waiting for it to clear before setting it, one would call
 506  * wait_on_bit() in threads waiting to be able to set the bit.
 507  * One uses wait_on_bit_lock() where one is waiting for the bit to
 508  * clear with the intention of setting it, and when done, clearing it.
 509  */
 510 static inline int wait_on_bit_lock(void *word, int bit,
 511                                 int (*action)(void *), unsigned mode)
 512 {
 513         if (!test_and_set_bit(bit, word))
 514                 return 0;
 515         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
 516 }
 517
 518 #endif /* __KERNEL__ */
 519
 520 #endif