include/linux/wait.h

   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 flags, void *key);
  30 int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, 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, struct lock_class_key *);
  81
  82 #define init_waitqueue_head(q)                          \
  83         do {                                            \
  84                 static struct lock_class_key __key;     \
  85                                                         \
  86                 __init_waitqueue_head((q), &__key);     \
  87         } while (0)
  88
  89 #ifdef CONFIG_LOCKDEP
  90 # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
  91         ({ init_waitqueue_head(&name); name; })
  92 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
  93         wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
  94 #else
  95 # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
  96 #endif
  97
  98 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
  99 {
 100         q->flags = 0;
 101         q->private = p;
 102         q->func = default_wake_function;
 103 }
 104
 105 static inline void init_waitqueue_func_entry(wait_queue_t *q,
 106                                         wait_queue_func_t func)
 107 {
 108         q->flags = 0;
 109         q->private = NULL;
 110         q->func = func;
 111 }
 112
 113 static inline int waitqueue_active(wait_queue_head_t *q)
 114 {
 115         return !list_empty(&q->task_list);
 116 }
 117
 118 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 119 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
 120 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 121
 122 static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
 123 {
 124         list_add(&new->task_list, &head->task_list);
 125 }
 126
 127 /*
 128  * Used for wake-one threads:
 129  */
 130 static inline void __add_wait_queue_exclusive(wait_queue_head_t *q,
 131                                               wait_queue_t *wait)
 132 {
 133         wait->flags |= WQ_FLAG_EXCLUSIVE;
 134         __add_wait_queue(q, wait);
 135 }
 136
 137 static inline void __add_wait_queue_tail(wait_queue_head_t *head,
 138                                          wait_queue_t *new)
 139 {
 140         list_add_tail(&new->task_list, &head->task_list);
 141 }
 142
 143 static inline void __add_wait_queue_tail_exclusive(wait_queue_head_t *q,
 144                                               wait_queue_t *wait)
 145 {
 146         wait->flags |= WQ_FLAG_EXCLUSIVE;
 147         __add_wait_queue_tail(q, wait);
 148 }
 149
 150 static inline void __remove_wait_queue(wait_queue_head_t *head,
 151                                                         wait_queue_t *old)
 152 {
 153         list_del(&old->task_list);
 154 }
 155
 156 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
 157 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
 158 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr,
 159                         void *key);
 160 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode);
 161 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
 162 void __wake_up_bit(wait_queue_head_t *, void *, int);
 163 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
 164 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
 165 void wake_up_bit(void *, int);
 166 int out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned);
 167 int out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned);
 168 wait_queue_head_t *bit_waitqueue(void *, int);
 169
 170 #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
 171 #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
 172 #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
 173 #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL)
 174
 175 #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
 176 #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
 177 #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
 178 #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
 179
 180 /*
 181  * Wakeup macros to be used to report events to the targets.
 182  */
 183 #define wake_up_poll(x, m)                              \
 184         __wake_up(x, TASK_NORMAL, 1, (void *) (m))
 185 #define wake_up_locked_poll(x, m)                               \
 186         __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
 187 #define wake_up_interruptible_poll(x, m)                        \
 188         __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
 189 #define wake_up_interruptible_sync_poll(x, m)                           \
 190         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
 191
 192 #define __wait_event(wq, condition)                                     \
 193 do {                                                                    \
 194         DEFINE_WAIT(__wait);                                            \
 195                                                                         \
 196         for (;;) {                                                      \
 197                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 198                 if (condition)                                          \
 199                         break;                                          \
 200                 schedule();                                             \
 201         }                                                               \
 202         finish_wait(&wq, &__wait);                                      \
 203 } while (0)
 204
 205 /**
 206  * wait_event - sleep until a condition gets true
 207  * @wq: the waitqueue to wait on
 208  * @condition: a C expression for the event to wait for
 209  *
 210  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 211  * @condition evaluates to true. The @condition is checked each time
 212  * the waitqueue @wq is woken up.
 213  *
 214  * wake_up() has to be called after changing any variable that could
 215  * change the result of the wait condition.
 216  */
 217 #define wait_event(wq, condition)                                       \
 218 do {                                                                    \
 219         if (condition)                                                  \
 220                 break;                                                  \
 221         __wait_event(wq, condition);                                    \
 222 } while (0)
 223
 224 #define __wait_event_timeout(wq, condition, ret)                        \
 225 do {                                                                    \
 226         DEFINE_WAIT(__wait);                                            \
 227                                                                         \
 228         for (;;) {                                                      \
 229                 prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE);    \
 230                 if (condition)                                          \
 231                         break;                                          \
 232                 ret = schedule_timeout(ret);                            \
 233                 if (!ret)                                               \
 234                         break;                                          \
 235         }                                                               \
 236         if (!ret && (condition))                                        \
 237                 ret = 1;                                                \
 238         finish_wait(&wq, &__wait);                                      \
 239 } while (0)
 240
 241 /**
 242  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
 243  * @wq: the waitqueue to wait on
 244  * @condition: a C expression for the event to wait for
 245  * @timeout: timeout, in jiffies
 246  *
 247  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
 248  * @condition evaluates to true. The @condition is checked each time
 249  * the waitqueue @wq is woken up.
 250  *
 251  * wake_up() has to be called after changing any variable that could
 252  * change the result of the wait condition.
 253  *
 254  * The function returns 0 if the @timeout elapsed, or the remaining
 255  * jiffies (at least 1) if the @condition evaluated to %true before
 256  * the @timeout elapsed.
 257  */
 258 #define wait_event_timeout(wq, condition, timeout)                      \
 259 ({                                                                      \
 260         long __ret = timeout;                                           \
 261         if (!(condition))                                               \
 262                 __wait_event_timeout(wq, condition, __ret);             \
 263         __ret;                                                          \
 264 })
 265
 266 #define __wait_event_interruptible(wq, condition, ret)                  \
 267 do {                                                                    \
 268         DEFINE_WAIT(__wait);                                            \
 269                                                                         \
 270         for (;;) {                                                      \
 271                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 272                 if (condition)                                          \
 273                         break;                                          \
 274                 if (!signal_pending(current)) {                         \
 275                         schedule();                                     \
 276                         continue;                                       \
 277                 }                                                       \
 278                 ret = -ERESTARTSYS;                                     \
 279                 break;                                                  \
 280         }                                                               \
 281         finish_wait(&wq, &__wait);                                      \
 282 } while (0)
 283
 284 /**
 285  * wait_event_interruptible - sleep until a condition gets true
 286  * @wq: the waitqueue to wait on
 287  * @condition: a C expression for the event to wait for
 288  *
 289  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 290  * @condition evaluates to true or a signal is received.
 291  * The @condition is checked each time the waitqueue @wq is woken up.
 292  *
 293  * wake_up() has to be called after changing any variable that could
 294  * change the result of the wait condition.
 295  *
 296  * The function will return -ERESTARTSYS if it was interrupted by a
 297  * signal and 0 if @condition evaluated to true.
 298  */
 299 #define wait_event_interruptible(wq, condition)                         \
 300 ({                                                                      \
 301         int __ret = 0;                                                  \
 302         if (!(condition))                                               \
 303                 __wait_event_interruptible(wq, condition, __ret);       \
 304         __ret;                                                          \
 305 })
 306
 307 #define __wait_event_interruptible_timeout(wq, condition, ret)          \
 308 do {                                                                    \
 309         DEFINE_WAIT(__wait);                                            \
 310                                                                         \
 311         for (;;) {                                                      \
 312                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 313                 if (condition)                                          \
 314                         break;                                          \
 315                 if (!signal_pending(current)) {                         \
 316                         ret = schedule_timeout(ret);                    \
 317                         if (!ret)                                       \
 318                                 break;                                  \
 319                         continue;                                       \
 320                 }                                                       \
 321                 ret = -ERESTARTSYS;                                     \
 322                 break;                                                  \
 323         }                                                               \
 324         if (!ret && (condition))                                        \
 325                 ret = 1;                                                \
 326         finish_wait(&wq, &__wait);                                      \
 327 } while (0)
 328
 329 /**
 330  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
 331  * @wq: the waitqueue to wait on
 332  * @condition: a C expression for the event to wait for
 333  * @timeout: timeout, in jiffies
 334  *
 335  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 336  * @condition evaluates to true or a signal is received.
 337  * The @condition is checked each time the waitqueue @wq is woken up.
 338  *
 339  * wake_up() has to be called after changing any variable that could
 340  * change the result of the wait condition.
 341  *
 342  * Returns:
 343  * 0 if the @timeout elapsed, -%ERESTARTSYS if it was interrupted by
 344  * a signal, or the remaining jiffies (at least 1) if the @condition
 345  * evaluated to %true before the @timeout elapsed.
 346  */
 347 #define wait_event_interruptible_timeout(wq, condition, timeout)        \
 348 ({                                                                      \
 349         long __ret = timeout;                                           \
 350         if (!(condition))                                               \
 351                 __wait_event_interruptible_timeout(wq, condition, __ret); \
 352         __ret;                                                          \
 353 })
 354
 355 #define __wait_event_interruptible_exclusive(wq, condition, ret)        \
 356 do {                                                                    \
 357         DEFINE_WAIT(__wait);                                            \
 358                                                                         \
 359         for (;;) {                                                      \
 360                 prepare_to_wait_exclusive(&wq, &__wait,                 \
 361                                         TASK_INTERRUPTIBLE);            \
 362                 if (condition) {                                        \
 363                         finish_wait(&wq, &__wait);                      \
 364                         break;                                          \
 365                 }                                                       \
 366                 if (!signal_pending(current)) {                         \
 367                         schedule();                                     \
 368                         continue;                                       \
 369                 }                                                       \
 370                 ret = -ERESTARTSYS;                                     \
 371                 abort_exclusive_wait(&wq, &__wait,                      \
 372                                 TASK_INTERRUPTIBLE, NULL);              \
 373                 break;                                                  \
 374         }                                                               \
 375 } while (0)
 376
 377 #define wait_event_interruptible_exclusive(wq, condition)               \
 378 ({                                                                      \
 379         int __ret = 0;                                                  \
 380         if (!(condition))                                               \
 381                 __wait_event_interruptible_exclusive(wq, condition, __ret);\
 382         __ret;                                                          \
 383 })
 384
 385
 386 #define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
 387 ({                                                                      \
 388         int __ret = 0;                                                  \
 389         DEFINE_WAIT(__wait);                                            \
 390         if (exclusive)                                                  \
 391                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                      \
 392         do {                                                            \
 393                 if (likely(list_empty(&__wait.task_list)))              \
 394                         __add_wait_queue_tail(&(wq), &__wait);          \
 395                 set_current_state(TASK_INTERRUPTIBLE);                  \
 396                 if (signal_pending(current)) {                          \
 397                         __ret = -ERESTARTSYS;                           \
 398                         break;                                          \
 399                 }                                                       \
 400                 if (irq)                                                \
 401                         spin_unlock_irq(&(wq).lock);                    \
 402                 else                                                    \
 403                         spin_unlock(&(wq).lock);                        \
 404                 schedule();                                             \
 405                 if (irq)                                                \
 406                         spin_lock_irq(&(wq).lock);                      \
 407                 else                                                    \
 408                         spin_lock(&(wq).lock);                          \
 409         } while (!(condition));                                         \
 410         __remove_wait_queue(&(wq), &__wait);                            \
 411         __set_current_state(TASK_RUNNING);                              \
 412         __ret;                                                          \
 413 })
 414
 415
 416 /**
 417  * wait_event_interruptible_locked - sleep until a condition gets true
 418  * @wq: the waitqueue to wait on
 419  * @condition: a C expression for the event to wait for
 420  *
 421  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 422  * @condition evaluates to true or a signal is received.
 423  * The @condition is checked each time the waitqueue @wq is woken up.
 424  *
 425  * It must be called with wq.lock being held.  This spinlock is
 426  * unlocked while sleeping but @condition testing is done while lock
 427  * is held and when this macro exits the lock is held.
 428  *
 429  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 430  * functions which must match the way they are locked/unlocked outside
 431  * of this macro.
 432  *
 433  * wake_up_locked() has to be called after changing any variable that could
 434  * change the result of the wait condition.
 435  *
 436  * The function will return -ERESTARTSYS if it was interrupted by a
 437  * signal and 0 if @condition evaluated to true.
 438  */
 439 #define wait_event_interruptible_locked(wq, condition)                  \
 440         ((condition)                                                    \
 441          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
 442
 443 /**
 444  * wait_event_interruptible_locked_irq - sleep until a condition gets true
 445  * @wq: the waitqueue to wait on
 446  * @condition: a C expression for the event to wait for
 447  *
 448  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 449  * @condition evaluates to true or a signal is received.
 450  * The @condition is checked each time the waitqueue @wq is woken up.
 451  *
 452  * It must be called with wq.lock being held.  This spinlock is
 453  * unlocked while sleeping but @condition testing is done while lock
 454  * is held and when this macro exits the lock is held.
 455  *
 456  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 457  * functions which must match the way they are locked/unlocked outside
 458  * of this macro.
 459  *
 460  * wake_up_locked() has to be called after changing any variable that could
 461  * change the result of the wait condition.
 462  *
 463  * The function will return -ERESTARTSYS if it was interrupted by a
 464  * signal and 0 if @condition evaluated to true.
 465  */
 466 #define wait_event_interruptible_locked_irq(wq, condition)              \
 467         ((condition)                                                    \
 468          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
 469
 470 /**
 471  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
 472  * @wq: the waitqueue to wait on
 473  * @condition: a C expression for the event to wait for
 474  *
 475  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 476  * @condition evaluates to true or a signal is received.
 477  * The @condition is checked each time the waitqueue @wq is woken up.
 478  *
 479  * It must be called with wq.lock being held.  This spinlock is
 480  * unlocked while sleeping but @condition testing is done while lock
 481  * is held and when this macro exits the lock is held.
 482  *
 483  * The lock is locked/unlocked using spin_lock()/spin_unlock()
 484  * functions which must match the way they are locked/unlocked outside
 485  * of this macro.
 486  *
 487  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 488  * set thus when other process waits process on the list if this
 489  * process is awaken further processes are not considered.
 490  *
 491  * wake_up_locked() has to be called after changing any variable that could
 492  * change the result of the wait condition.
 493  *
 494  * The function will return -ERESTARTSYS if it was interrupted by a
 495  * signal and 0 if @condition evaluated to true.
 496  */
 497 #define wait_event_interruptible_exclusive_locked(wq, condition)        \
 498         ((condition)                                                    \
 499          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
 500
 501 /**
 502  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
 503  * @wq: the waitqueue to wait on
 504  * @condition: a C expression for the event to wait for
 505  *
 506  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 507  * @condition evaluates to true or a signal is received.
 508  * The @condition is checked each time the waitqueue @wq is woken up.
 509  *
 510  * It must be called with wq.lock being held.  This spinlock is
 511  * unlocked while sleeping but @condition testing is done while lock
 512  * is held and when this macro exits the lock is held.
 513  *
 514  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
 515  * functions which must match the way they are locked/unlocked outside
 516  * of this macro.
 517  *
 518  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
 519  * set thus when other process waits process on the list if this
 520  * process is awaken further processes are not considered.
 521  *
 522  * wake_up_locked() has to be called after changing any variable that could
 523  * change the result of the wait condition.
 524  *
 525  * The function will return -ERESTARTSYS if it was interrupted by a
 526  * signal and 0 if @condition evaluated to true.
 527  */
 528 #define wait_event_interruptible_exclusive_locked_irq(wq, condition)    \
 529         ((condition)                                                    \
 530          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
 531
 532
 533 #define __wait_event_interruptible_lock_irq_timeout(wq, condition,      \
 534                                                     lock, ret)          \
 535 do {                                                                    \
 536         DEFINE_WAIT(__wait);                                            \
 537                                                                         \
 538         for (;;) {                                                      \
 539                 prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);      \
 540                 if (condition)                                          \
 541                         break;                                          \
 542                 if (signal_pending(current)) {                          \
 543                         ret = -ERESTARTSYS;                             \
 544                         break;                                          \
 545                 }                                                       \
 546                 spin_unlock_irq(&lock);                                 \
 547                 ret = schedule_timeout(ret);                            \
 548                 spin_lock_irq(&lock);                                   \
 549                 if (!ret)                                               \
 550                         break;                                          \
 551         }                                                               \
 552         finish_wait(&wq, &__wait);                                      \
 553 } while (0)
 554
 555 /**
 556  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets true or a timeout elapses.
 557  *              The condition is checked under the lock. This is expected
 558  *              to be called with the lock taken.
 559  * @wq: the waitqueue to wait on
 560  * @condition: a C expression for the event to wait for
 561  * @lock: a locked spinlock_t, which will be released before schedule()
 562  *        and reacquired afterwards.
 563  * @timeout: timeout, in jiffies
 564  *
 565  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
 566  * @condition evaluates to true or signal is received. The @condition is
 567  * checked each time the waitqueue @wq is woken up.
 568  *
 569  * wake_up() has to be called after changing any variable that could
 570  * change the result of the wait condition.
 571  *
 572  * This is supposed to be called while holding the lock. The lock is
 573  * dropped before going to sleep and is reacquired afterwards.
 574  *
 575  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
 576  * was interrupted by a signal, and the remaining jiffies otherwise
 577  * if the condition evaluated to true before the timeout elapsed.
 578  */
 579 #define wait_event_interruptible_lock_irq_timeout(wq, condition, lock,  \
 580                                                   timeout)              \
 581 ({                                                                      \
 582         int __ret = timeout;                                            \
 583                                                                         \
 584         if (!(condition))                                               \
 585                 __wait_event_interruptible_lock_irq_timeout(            \
 586                                         wq, condition, lock, __ret);    \
 587         __ret;                                                          \
 588 })
 589
 590
 591 #define __wait_event_killable(wq, condition, ret)                       \
 592 do {                                                                    \
 593         DEFINE_WAIT(__wait);                                            \
 594                                                                         \
 595         for (;;) {                                                      \
 596                 prepare_to_wait(&wq, &__wait, TASK_KILLABLE);           \
 597                 if (condition)                                          \
 598                         break;                                          \
 599                 if (!fatal_signal_pending(current)) {                   \
 600                         schedule();                                     \
 601                         continue;                                       \
 602                 }                                                       \
 603                 ret = -ERESTARTSYS;                                     \
 604                 break;                                                  \
 605         }                                                               \
 606         finish_wait(&wq, &__wait);                                      \
 607 } while (0)
 608
 609 /**
 610  * wait_event_killable - sleep until a condition gets true
 611  * @wq: the waitqueue to wait on
 612  * @condition: a C expression for the event to wait for
 613  *
 614  * The process is put to sleep (TASK_KILLABLE) until the
 615  * @condition evaluates to true or a signal is received.
 616  * The @condition is checked each time the waitqueue @wq is woken up.
 617  *
 618  * wake_up() has to be called after changing any variable that could
 619  * change the result of the wait condition.
 620  *
 621  * The function will return -ERESTARTSYS if it was interrupted by a
 622  * signal and 0 if @condition evaluated to true.
 623  */
 624 #define wait_event_killable(wq, condition)                              \
 625 ({                                                                      \
 626         int __ret = 0;                                                  \
 627         if (!(condition))                                               \
 628                 __wait_event_killable(wq, condition, __ret);            \
 629         __ret;                                                          \
 630 })
 631
 632 /*
 633  * These are the old interfaces to sleep waiting for an event.
 634  * They are racy.  DO NOT use them, use the wait_event* interfaces above.
 635  * We plan to remove these interfaces.
 636  */
 637 extern void sleep_on(wait_queue_head_t *q);
 638 extern long sleep_on_timeout(wait_queue_head_t *q,
 639                                       signed long timeout);
 640 extern void interruptible_sleep_on(wait_queue_head_t *q);
 641 extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
 642                                            signed long timeout);
 643
 644 /*
 645  * Waitqueues which are removed from the waitqueue_head at wakeup time
 646  */
 647 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
 648 void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
 649 void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
 650 void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
 651                         unsigned int mode, void *key);
 652 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 653 int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
 654
 655 #define DEFINE_WAIT_FUNC(name, function)                                \
 656         wait_queue_t name = {                                           \
 657                 .private        = current,                              \
 658                 .func           = function,                             \
 659                 .task_list      = LIST_HEAD_INIT((name).task_list),     \
 660         }
 661
 662 #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
 663
 664 #define DEFINE_WAIT_BIT(name, word, bit)                                \
 665         struct wait_bit_queue name = {                                  \
 666                 .key = __WAIT_BIT_KEY_INITIALIZER(word, bit),           \
 667                 .wait   = {                                             \
 668                         .private        = current,                      \
 669                         .func           = wake_bit_function,            \
 670                         .task_list      =                               \
 671                                 LIST_HEAD_INIT((name).wait.task_list),  \
 672                 },                                                      \
 673         }
 674
 675 #define init_wait(wait)                                                 \
 676         do {                                                            \
 677                 (wait)->private = current;                              \
 678                 (wait)->func = autoremove_wake_function;                \
 679                 INIT_LIST_HEAD(&(wait)->task_list);                     \
 680                 (wait)->flags = 0;                                      \
 681         } while (0)
 682
 683 /**
 684  * wait_on_bit - wait for a bit to be cleared
 685  * @word: the word being waited on, a kernel virtual address
 686  * @bit: the bit of the word being waited on
 687  * @action: the function used to sleep, which may take special actions
 688  * @mode: the task state to sleep in
 689  *
 690  * There is a standard hashed waitqueue table for generic use. This
 691  * is the part of the hashtable's accessor API that waits on a bit.
 692  * For instance, if one were to have waiters on a bitflag, one would
 693  * call wait_on_bit() in threads waiting for the bit to clear.
 694  * One uses wait_on_bit() where one is waiting for the bit to clear,
 695  * but has no intention of setting it.
 696  */
 697 static inline int wait_on_bit(void *word, int bit,
 698                                 int (*action)(void *), unsigned mode)
 699 {
 700         if (!test_bit(bit, word))
 701                 return 0;
 702         return out_of_line_wait_on_bit(word, bit, action, mode);
 703 }
 704
 705 /**
 706  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
 707  * @word: the word being waited on, a kernel virtual address
 708  * @bit: the bit of the word being waited on
 709  * @action: the function used to sleep, which may take special actions
 710  * @mode: the task state to sleep in
 711  *
 712  * There is a standard hashed waitqueue table for generic use. This
 713  * is the part of the hashtable's accessor API that waits on a bit
 714  * when one intends to set it, for instance, trying to lock bitflags.
 715  * For instance, if one were to have waiters trying to set bitflag
 716  * and waiting for it to clear before setting it, one would call
 717  * wait_on_bit() in threads waiting to be able to set the bit.
 718  * One uses wait_on_bit_lock() where one is waiting for the bit to
 719  * clear with the intention of setting it, and when done, clearing it.
 720  */
 721 static inline int wait_on_bit_lock(void *word, int bit,
 722                                 int (*action)(void *), unsigned mode)
 723 {
 724         if (!test_and_set_bit(bit, word))
 725                 return 0;
 726         return out_of_line_wait_on_bit_lock(word, bit, action, mode);
 727 }
 728
 729 #endif /* __KERNEL__ */
 730
 731 #endif