LCOV - code coverage report
Current view: top level - include/linux - wait.h (source / functions) Hit Total Coverage
Test: landlock.info Lines: 25 29 86.2 %
Date: 2021-04-22 12:43:58 Functions: 1 1 100.0 %

          Line data    Source code
       1             : /* SPDX-License-Identifier: GPL-2.0 */
       2             : #ifndef _LINUX_WAIT_H
       3             : #define _LINUX_WAIT_H
       4             : /*
       5             :  * Linux wait queue related types and methods
       6             :  */
       7             : #include <linux/list.h>
       8             : #include <linux/stddef.h>
       9             : #include <linux/spinlock.h>
      10             : 
      11             : #include <asm/current.h>
      12             : #include <uapi/linux/wait.h>
      13             : 
      14             : typedef struct wait_queue_entry wait_queue_entry_t;
      15             : 
      16             : typedef int (*wait_queue_func_t)(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key);
      17             : int default_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key);
      18             : 
      19             : /* wait_queue_entry::flags */
      20             : #define WQ_FLAG_EXCLUSIVE       0x01
      21             : #define WQ_FLAG_WOKEN           0x02
      22             : #define WQ_FLAG_BOOKMARK        0x04
      23             : #define WQ_FLAG_CUSTOM          0x08
      24             : #define WQ_FLAG_DONE            0x10
      25             : #define WQ_FLAG_PRIORITY        0x20
      26             : 
      27             : /*
      28             :  * A single wait-queue entry structure:
      29             :  */
      30             : struct wait_queue_entry {
      31             :         unsigned int            flags;
      32             :         void                    *private;
      33             :         wait_queue_func_t       func;
      34             :         struct list_head        entry;
      35             : };
      36             : 
      37             : struct wait_queue_head {
      38             :         spinlock_t              lock;
      39             :         struct list_head        head;
      40             : };
      41             : typedef struct wait_queue_head wait_queue_head_t;
      42             : 
      43             : struct task_struct;
      44             : 
      45             : /*
      46             :  * Macros for declaration and initialisaton of the datatypes
      47             :  */
      48             : 
      49             : #define __WAITQUEUE_INITIALIZER(name, tsk) {                                    \
      50             :         .private        = tsk,                                                  \
      51             :         .func           = default_wake_function,                                \
      52             :         .entry          = { NULL, NULL } }
      53             : 
      54             : #define DECLARE_WAITQUEUE(name, tsk)                                            \
      55             :         struct wait_queue_entry name = __WAITQUEUE_INITIALIZER(name, tsk)
      56             : 
      57             : #define __WAIT_QUEUE_HEAD_INITIALIZER(name) {                                   \
      58             :         .lock           = __SPIN_LOCK_UNLOCKED(name.lock),                      \
      59             :         .head           = { &(name).head, &(name).head } }
      60             : 
      61             : #define DECLARE_WAIT_QUEUE_HEAD(name) \
      62             :         struct wait_queue_head name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
      63             : 
      64             : extern void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *);
      65             : 
      66             : #define init_waitqueue_head(wq_head)                                            \
      67             :         do {                                                                    \
      68             :                 static struct lock_class_key __key;                             \
      69             :                                                                                 \
      70             :                 __init_waitqueue_head((wq_head), #wq_head, &__key);         \
      71             :         } while (0)
      72             : 
      73             : #ifdef CONFIG_LOCKDEP
      74             : # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
      75             :         ({ init_waitqueue_head(&name); name; })
      76             : # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
      77             :         struct wait_queue_head name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
      78             : #else
      79             : # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
      80             : #endif
      81             : 
      82             : static inline void init_waitqueue_entry(struct wait_queue_entry *wq_entry, struct task_struct *p)
      83             : {
      84             :         wq_entry->flags              = 0;
      85             :         wq_entry->private    = p;
      86             :         wq_entry->func               = default_wake_function;
      87             : }
      88             : 
      89             : static inline void
      90        2531 : init_waitqueue_func_entry(struct wait_queue_entry *wq_entry, wait_queue_func_t func)
      91             : {
      92        2531 :         wq_entry->flags              = 0;
      93        2531 :         wq_entry->private    = NULL;
      94        2531 :         wq_entry->func               = func;
      95             : }
      96             : 
      97             : /**
      98             :  * waitqueue_active -- locklessly test for waiters on the queue
      99             :  * @wq_head: the waitqueue to test for waiters
     100             :  *
     101             :  * returns true if the wait list is not empty
     102             :  *
     103             :  * NOTE: this function is lockless and requires care, incorrect usage _will_
     104             :  * lead to sporadic and non-obvious failure.
     105             :  *
     106             :  * Use either while holding wait_queue_head::lock or when used for wakeups
     107             :  * with an extra smp_mb() like::
     108             :  *
     109             :  *      CPU0 - waker                    CPU1 - waiter
     110             :  *
     111             :  *                                      for (;;) {
     112             :  *      @cond = true;                     prepare_to_wait(&wq_head, &wait, state);
     113             :  *      smp_mb();                         // smp_mb() from set_current_state()
     114             :  *      if (waitqueue_active(wq_head))         if (@cond)
     115             :  *        wake_up(wq_head);                      break;
     116             :  *                                        schedule();
     117             :  *                                      }
     118             :  *                                      finish_wait(&wq_head, &wait);
     119             :  *
     120             :  * Because without the explicit smp_mb() it's possible for the
     121             :  * waitqueue_active() load to get hoisted over the @cond store such that we'll
     122             :  * observe an empty wait list while the waiter might not observe @cond.
     123             :  *
     124             :  * Also note that this 'optimization' trades a spin_lock() for an smp_mb(),
     125             :  * which (when the lock is uncontended) are of roughly equal cost.
     126             :  */
     127       40245 : static inline int waitqueue_active(struct wait_queue_head *wq_head)
     128             : {
     129       34606 :         return !list_empty(&wq_head->head);
     130             : }
     131             : 
     132             : /**
     133             :  * wq_has_single_sleeper - check if there is only one sleeper
     134             :  * @wq_head: wait queue head
     135             :  *
     136             :  * Returns true of wq_head has only one sleeper on the list.
     137             :  *
     138             :  * Please refer to the comment for waitqueue_active.
     139             :  */
     140           0 : static inline bool wq_has_single_sleeper(struct wait_queue_head *wq_head)
     141             : {
     142           0 :         return list_is_singular(&wq_head->head);
     143             : }
     144             : 
     145             : /**
     146             :  * wq_has_sleeper - check if there are any waiting processes
     147             :  * @wq_head: wait queue head
     148             :  *
     149             :  * Returns true if wq_head has waiting processes
     150             :  *
     151             :  * Please refer to the comment for waitqueue_active.
     152             :  */
     153        7304 : static inline bool wq_has_sleeper(struct wait_queue_head *wq_head)
     154             : {
     155             :         /*
     156             :          * We need to be sure we are in sync with the
     157             :          * add_wait_queue modifications to the wait queue.
     158             :          *
     159             :          * This memory barrier should be paired with one on the
     160             :          * waiting side.
     161             :          */
     162        7304 :         smp_mb();
     163        7305 :         return waitqueue_active(wq_head);
     164             : }
     165             : 
     166             : extern void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
     167             : extern void add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
     168             : extern void add_wait_queue_priority(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
     169             : extern void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
     170             : 
     171        6405 : static inline void __add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
     172             : {
     173        6405 :         struct list_head *head = &wq_head->head;
     174        6405 :         struct wait_queue_entry *wq;
     175             : 
     176        6405 :         list_for_each_entry(wq, &wq_head->head, entry) {
     177         271 :                 if (!(wq->flags & WQ_FLAG_PRIORITY))
     178             :                         break;
     179           0 :                 head = &wq->entry;
     180             :         }
     181        6405 :         list_add(&wq_entry->entry, head);
     182        6405 : }
     183             : 
     184             : /*
     185             :  * Used for wake-one threads:
     186             :  */
     187             : static inline void
     188        1534 : __add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
     189             : {
     190        1534 :         wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
     191        1534 :         __add_wait_queue(wq_head, wq_entry);
     192        1534 : }
     193             : 
     194         959 : static inline void __add_wait_queue_entry_tail(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
     195             : {
     196         959 :         list_add_tail(&wq_entry->entry, &wq_head->head);
     197         959 : }
     198             : 
     199             : static inline void
     200             : __add_wait_queue_entry_tail_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
     201             : {
     202             :         wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
     203             :         __add_wait_queue_entry_tail(wq_head, wq_entry);
     204             : }
     205             : 
     206             : static inline void
     207        3070 : __remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
     208             : {
     209        3070 :         list_del(&wq_entry->entry);
     210           0 : }
     211             : 
     212             : void __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
     213             : void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
     214             : void __wake_up_locked_key_bookmark(struct wait_queue_head *wq_head,
     215             :                 unsigned int mode, void *key, wait_queue_entry_t *bookmark);
     216             : void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
     217             : void __wake_up_locked_sync_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
     218             : void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr);
     219             : void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode);
     220             : 
     221             : #define wake_up(x)                      __wake_up(x, TASK_NORMAL, 1, NULL)
     222             : #define wake_up_nr(x, nr)               __wake_up(x, TASK_NORMAL, nr, NULL)
     223             : #define wake_up_all(x)                  __wake_up(x, TASK_NORMAL, 0, NULL)
     224             : #define wake_up_locked(x)               __wake_up_locked((x), TASK_NORMAL, 1)
     225             : #define wake_up_all_locked(x)           __wake_up_locked((x), TASK_NORMAL, 0)
     226             : 
     227             : #define wake_up_interruptible(x)        __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
     228             : #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
     229             : #define wake_up_interruptible_all(x)    __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
     230             : #define wake_up_interruptible_sync(x)   __wake_up_sync((x), TASK_INTERRUPTIBLE)
     231             : 
     232             : /*
     233             :  * Wakeup macros to be used to report events to the targets.
     234             :  */
     235             : #define poll_to_key(m) ((void *)(__force uintptr_t)(__poll_t)(m))
     236             : #define key_to_poll(m) ((__force __poll_t)(uintptr_t)(void *)(m))
     237             : #define wake_up_poll(x, m)                                                      \
     238             :         __wake_up(x, TASK_NORMAL, 1, poll_to_key(m))
     239             : #define wake_up_locked_poll(x, m)                                               \
     240             :         __wake_up_locked_key((x), TASK_NORMAL, poll_to_key(m))
     241             : #define wake_up_interruptible_poll(x, m)                                        \
     242             :         __wake_up(x, TASK_INTERRUPTIBLE, 1, poll_to_key(m))
     243             : #define wake_up_interruptible_sync_poll(x, m)                                   \
     244             :         __wake_up_sync_key((x), TASK_INTERRUPTIBLE, poll_to_key(m))
     245             : #define wake_up_interruptible_sync_poll_locked(x, m)                            \
     246             :         __wake_up_locked_sync_key((x), TASK_INTERRUPTIBLE, poll_to_key(m))
     247             : 
     248             : #define ___wait_cond_timeout(condition)                                         \
     249             : ({                                                                              \
     250             :         bool __cond = (condition);                                              \
     251             :         if (__cond && !__ret)                                                   \
     252             :                 __ret = 1;                                                      \
     253             :         __cond || !__ret;                                                       \
     254             : })
     255             : 
     256             : #define ___wait_is_interruptible(state)                                         \
     257             :         (!__builtin_constant_p(state) ||                                        \
     258             :                 state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE)          \
     259             : 
     260             : extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags);
     261             : 
     262             : /*
     263             :  * The below macro ___wait_event() has an explicit shadow of the __ret
     264             :  * variable when used from the wait_event_*() macros.
     265             :  *
     266             :  * This is so that both can use the ___wait_cond_timeout() construct
     267             :  * to wrap the condition.
     268             :  *
     269             :  * The type inconsistency of the wait_event_*() __ret variable is also
     270             :  * on purpose; we use long where we can return timeout values and int
     271             :  * otherwise.
     272             :  */
     273             : 
     274             : #define ___wait_event(wq_head, condition, state, exclusive, ret, cmd)           \
     275             : ({                                                                              \
     276             :         __label__ __out;                                                        \
     277             :         struct wait_queue_entry __wq_entry;                                     \
     278             :         long __ret = ret;       /* explicit shadow */                           \
     279             :                                                                                 \
     280             :         init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0);    \
     281             :         for (;;) {                                                              \
     282             :                 long __int = prepare_to_wait_event(&wq_head, &__wq_entry, state);\
     283             :                                                                                 \
     284             :                 if (condition)                                                  \
     285             :                         break;                                                  \
     286             :                                                                                 \
     287             :                 if (___wait_is_interruptible(state) && __int) {                 \
     288             :                         __ret = __int;                                          \
     289             :                         goto __out;                                             \
     290             :                 }                                                               \
     291             :                                                                                 \
     292             :                 cmd;                                                            \
     293             :         }                                                                       \
     294             :         finish_wait(&wq_head, &__wq_entry);                                     \
     295             : __out:  __ret;                                                                  \
     296             : })
     297             : 
     298             : #define __wait_event(wq_head, condition)                                        \
     299             :         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
     300             :                             schedule())
     301             : 
     302             : /**
     303             :  * wait_event - sleep until a condition gets true
     304             :  * @wq_head: the waitqueue to wait on
     305             :  * @condition: a C expression for the event to wait for
     306             :  *
     307             :  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
     308             :  * @condition evaluates to true. The @condition is checked each time
     309             :  * the waitqueue @wq_head is woken up.
     310             :  *
     311             :  * wake_up() has to be called after changing any variable that could
     312             :  * change the result of the wait condition.
     313             :  */
     314             : #define wait_event(wq_head, condition)                                          \
     315             : do {                                                                            \
     316             :         might_sleep();                                                          \
     317             :         if (condition)                                                          \
     318             :                 break;                                                          \
     319             :         __wait_event(wq_head, condition);                                       \
     320             : } while (0)
     321             : 
     322             : #define __io_wait_event(wq_head, condition)                                     \
     323             :         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
     324             :                             io_schedule())
     325             : 
     326             : /*
     327             :  * io_wait_event() -- like wait_event() but with io_schedule()
     328             :  */
     329             : #define io_wait_event(wq_head, condition)                                       \
     330             : do {                                                                            \
     331             :         might_sleep();                                                          \
     332             :         if (condition)                                                          \
     333             :                 break;                                                          \
     334             :         __io_wait_event(wq_head, condition);                                    \
     335             : } while (0)
     336             : 
     337             : #define __wait_event_freezable(wq_head, condition)                              \
     338             :         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
     339             :                             freezable_schedule())
     340             : 
     341             : /**
     342             :  * wait_event_freezable - sleep (or freeze) until a condition gets true
     343             :  * @wq_head: the waitqueue to wait on
     344             :  * @condition: a C expression for the event to wait for
     345             :  *
     346             :  * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
     347             :  * to system load) until the @condition evaluates to true. The
     348             :  * @condition is checked each time the waitqueue @wq_head is woken up.
     349             :  *
     350             :  * wake_up() has to be called after changing any variable that could
     351             :  * change the result of the wait condition.
     352             :  */
     353             : #define wait_event_freezable(wq_head, condition)                                \
     354             : ({                                                                              \
     355             :         int __ret = 0;                                                          \
     356             :         might_sleep();                                                          \
     357             :         if (!(condition))                                                       \
     358             :                 __ret = __wait_event_freezable(wq_head, condition);             \
     359             :         __ret;                                                                  \
     360             : })
     361             : 
     362             : #define __wait_event_timeout(wq_head, condition, timeout)                       \
     363             :         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
     364             :                       TASK_UNINTERRUPTIBLE, 0, timeout,                         \
     365             :                       __ret = schedule_timeout(__ret))
     366             : 
     367             : /**
     368             :  * wait_event_timeout - sleep until a condition gets true or a timeout elapses
     369             :  * @wq_head: the waitqueue to wait on
     370             :  * @condition: a C expression for the event to wait for
     371             :  * @timeout: timeout, in jiffies
     372             :  *
     373             :  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
     374             :  * @condition evaluates to true. The @condition is checked each time
     375             :  * the waitqueue @wq_head is woken up.
     376             :  *
     377             :  * wake_up() has to be called after changing any variable that could
     378             :  * change the result of the wait condition.
     379             :  *
     380             :  * Returns:
     381             :  * 0 if the @condition evaluated to %false after the @timeout elapsed,
     382             :  * 1 if the @condition evaluated to %true after the @timeout elapsed,
     383             :  * or the remaining jiffies (at least 1) if the @condition evaluated
     384             :  * to %true before the @timeout elapsed.
     385             :  */
     386             : #define wait_event_timeout(wq_head, condition, timeout)                         \
     387             : ({                                                                              \
     388             :         long __ret = timeout;                                                   \
     389             :         might_sleep();                                                          \
     390             :         if (!___wait_cond_timeout(condition))                                   \
     391             :                 __ret = __wait_event_timeout(wq_head, condition, timeout);      \
     392             :         __ret;                                                                  \
     393             : })
     394             : 
     395             : #define __wait_event_freezable_timeout(wq_head, condition, timeout)             \
     396             :         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
     397             :                       TASK_INTERRUPTIBLE, 0, timeout,                           \
     398             :                       __ret = freezable_schedule_timeout(__ret))
     399             : 
     400             : /*
     401             :  * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
     402             :  * increasing load and is freezable.
     403             :  */
     404             : #define wait_event_freezable_timeout(wq_head, condition, timeout)               \
     405             : ({                                                                              \
     406             :         long __ret = timeout;                                                   \
     407             :         might_sleep();                                                          \
     408             :         if (!___wait_cond_timeout(condition))                                   \
     409             :                 __ret = __wait_event_freezable_timeout(wq_head, condition, timeout); \
     410             :         __ret;                                                                  \
     411             : })
     412             : 
     413             : #define __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2)              \
     414             :         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 1, 0,     \
     415             :                             cmd1; schedule(); cmd2)
     416             : /*
     417             :  * Just like wait_event_cmd(), except it sets exclusive flag
     418             :  */
     419             : #define wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2)                \
     420             : do {                                                                            \
     421             :         if (condition)                                                          \
     422             :                 break;                                                          \
     423             :         __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2);             \
     424             : } while (0)
     425             : 
     426             : #define __wait_event_cmd(wq_head, condition, cmd1, cmd2)                        \
     427             :         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
     428             :                             cmd1; schedule(); cmd2)
     429             : 
     430             : /**
     431             :  * wait_event_cmd - sleep until a condition gets true
     432             :  * @wq_head: the waitqueue to wait on
     433             :  * @condition: a C expression for the event to wait for
     434             :  * @cmd1: the command will be executed before sleep
     435             :  * @cmd2: the command will be executed after sleep
     436             :  *
     437             :  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
     438             :  * @condition evaluates to true. The @condition is checked each time
     439             :  * the waitqueue @wq_head is woken up.
     440             :  *
     441             :  * wake_up() has to be called after changing any variable that could
     442             :  * change the result of the wait condition.
     443             :  */
     444             : #define wait_event_cmd(wq_head, condition, cmd1, cmd2)                          \
     445             : do {                                                                            \
     446             :         if (condition)                                                          \
     447             :                 break;                                                          \
     448             :         __wait_event_cmd(wq_head, condition, cmd1, cmd2);                       \
     449             : } while (0)
     450             : 
     451             : #define __wait_event_interruptible(wq_head, condition)                          \
     452             :         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
     453             :                       schedule())
     454             : 
     455             : /**
     456             :  * wait_event_interruptible - sleep until a condition gets true
     457             :  * @wq_head: the waitqueue to wait on
     458             :  * @condition: a C expression for the event to wait for
     459             :  *
     460             :  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
     461             :  * @condition evaluates to true or a signal is received.
     462             :  * The @condition is checked each time the waitqueue @wq_head is woken up.
     463             :  *
     464             :  * wake_up() has to be called after changing any variable that could
     465             :  * change the result of the wait condition.
     466             :  *
     467             :  * The function will return -ERESTARTSYS if it was interrupted by a
     468             :  * signal and 0 if @condition evaluated to true.
     469             :  */
     470             : #define wait_event_interruptible(wq_head, condition)                            \
     471             : ({                                                                              \
     472             :         int __ret = 0;                                                          \
     473             :         might_sleep();                                                          \
     474             :         if (!(condition))                                                       \
     475             :                 __ret = __wait_event_interruptible(wq_head, condition);         \
     476             :         __ret;                                                                  \
     477             : })
     478             : 
     479             : #define __wait_event_interruptible_timeout(wq_head, condition, timeout)         \
     480             :         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
     481             :                       TASK_INTERRUPTIBLE, 0, timeout,                           \
     482             :                       __ret = schedule_timeout(__ret))
     483             : 
     484             : /**
     485             :  * wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
     486             :  * @wq_head: the waitqueue to wait on
     487             :  * @condition: a C expression for the event to wait for
     488             :  * @timeout: timeout, in jiffies
     489             :  *
     490             :  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
     491             :  * @condition evaluates to true or a signal is received.
     492             :  * The @condition is checked each time the waitqueue @wq_head is woken up.
     493             :  *
     494             :  * wake_up() has to be called after changing any variable that could
     495             :  * change the result of the wait condition.
     496             :  *
     497             :  * Returns:
     498             :  * 0 if the @condition evaluated to %false after the @timeout elapsed,
     499             :  * 1 if the @condition evaluated to %true after the @timeout elapsed,
     500             :  * the remaining jiffies (at least 1) if the @condition evaluated
     501             :  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
     502             :  * interrupted by a signal.
     503             :  */
     504             : #define wait_event_interruptible_timeout(wq_head, condition, timeout)           \
     505             : ({                                                                              \
     506             :         long __ret = timeout;                                                   \
     507             :         might_sleep();                                                          \
     508             :         if (!___wait_cond_timeout(condition))                                   \
     509             :                 __ret = __wait_event_interruptible_timeout(wq_head,             \
     510             :                                                 condition, timeout);            \
     511             :         __ret;                                                                  \
     512             : })
     513             : 
     514             : #define __wait_event_hrtimeout(wq_head, condition, timeout, state)              \
     515             : ({                                                                              \
     516             :         int __ret = 0;                                                          \
     517             :         struct hrtimer_sleeper __t;                                             \
     518             :                                                                                 \
     519             :         hrtimer_init_sleeper_on_stack(&__t, CLOCK_MONOTONIC,                        \
     520             :                                       HRTIMER_MODE_REL);                        \
     521             :         if ((timeout) != KTIME_MAX)                                             \
     522             :                 hrtimer_start_range_ns(&__t.timer, timeout,                 \
     523             :                                        current->timer_slack_ns,                      \
     524             :                                        HRTIMER_MODE_REL);                       \
     525             :                                                                                 \
     526             :         __ret = ___wait_event(wq_head, condition, state, 0, 0,                  \
     527             :                 if (!__t.task) {                                                \
     528             :                         __ret = -ETIME;                                         \
     529             :                         break;                                                  \
     530             :                 }                                                               \
     531             :                 schedule());                                                    \
     532             :                                                                                 \
     533             :         hrtimer_cancel(&__t.timer);                                         \
     534             :         destroy_hrtimer_on_stack(&__t.timer);                                       \
     535             :         __ret;                                                                  \
     536             : })
     537             : 
     538             : /**
     539             :  * wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
     540             :  * @wq_head: the waitqueue to wait on
     541             :  * @condition: a C expression for the event to wait for
     542             :  * @timeout: timeout, as a ktime_t
     543             :  *
     544             :  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
     545             :  * @condition evaluates to true or a signal is received.
     546             :  * The @condition is checked each time the waitqueue @wq_head is woken up.
     547             :  *
     548             :  * wake_up() has to be called after changing any variable that could
     549             :  * change the result of the wait condition.
     550             :  *
     551             :  * The function returns 0 if @condition became true, or -ETIME if the timeout
     552             :  * elapsed.
     553             :  */
     554             : #define wait_event_hrtimeout(wq_head, condition, timeout)                       \
     555             : ({                                                                              \
     556             :         int __ret = 0;                                                          \
     557             :         might_sleep();                                                          \
     558             :         if (!(condition))                                                       \
     559             :                 __ret = __wait_event_hrtimeout(wq_head, condition, timeout,     \
     560             :                                                TASK_UNINTERRUPTIBLE);           \
     561             :         __ret;                                                                  \
     562             : })
     563             : 
     564             : /**
     565             :  * wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
     566             :  * @wq: the waitqueue to wait on
     567             :  * @condition: a C expression for the event to wait for
     568             :  * @timeout: timeout, as a ktime_t
     569             :  *
     570             :  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
     571             :  * @condition evaluates to true or a signal is received.
     572             :  * The @condition is checked each time the waitqueue @wq is woken up.
     573             :  *
     574             :  * wake_up() has to be called after changing any variable that could
     575             :  * change the result of the wait condition.
     576             :  *
     577             :  * The function returns 0 if @condition became true, -ERESTARTSYS if it was
     578             :  * interrupted by a signal, or -ETIME if the timeout elapsed.
     579             :  */
     580             : #define wait_event_interruptible_hrtimeout(wq, condition, timeout)              \
     581             : ({                                                                              \
     582             :         long __ret = 0;                                                         \
     583             :         might_sleep();                                                          \
     584             :         if (!(condition))                                                       \
     585             :                 __ret = __wait_event_hrtimeout(wq, condition, timeout,          \
     586             :                                                TASK_INTERRUPTIBLE);             \
     587             :         __ret;                                                                  \
     588             : })
     589             : 
     590             : #define __wait_event_interruptible_exclusive(wq, condition)                     \
     591             :         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,                  \
     592             :                       schedule())
     593             : 
     594             : #define wait_event_interruptible_exclusive(wq, condition)                       \
     595             : ({                                                                              \
     596             :         int __ret = 0;                                                          \
     597             :         might_sleep();                                                          \
     598             :         if (!(condition))                                                       \
     599             :                 __ret = __wait_event_interruptible_exclusive(wq, condition);    \
     600             :         __ret;                                                                  \
     601             : })
     602             : 
     603             : #define __wait_event_killable_exclusive(wq, condition)                          \
     604             :         ___wait_event(wq, condition, TASK_KILLABLE, 1, 0,                       \
     605             :                       schedule())
     606             : 
     607             : #define wait_event_killable_exclusive(wq, condition)                            \
     608             : ({                                                                              \
     609             :         int __ret = 0;                                                          \
     610             :         might_sleep();                                                          \
     611             :         if (!(condition))                                                       \
     612             :                 __ret = __wait_event_killable_exclusive(wq, condition);         \
     613             :         __ret;                                                                  \
     614             : })
     615             : 
     616             : 
     617             : #define __wait_event_freezable_exclusive(wq, condition)                         \
     618             :         ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0,                  \
     619             :                         freezable_schedule())
     620             : 
     621             : #define wait_event_freezable_exclusive(wq, condition)                           \
     622             : ({                                                                              \
     623             :         int __ret = 0;                                                          \
     624             :         might_sleep();                                                          \
     625             :         if (!(condition))                                                       \
     626             :                 __ret = __wait_event_freezable_exclusive(wq, condition);        \
     627             :         __ret;                                                                  \
     628             : })
     629             : 
     630             : /**
     631             :  * wait_event_idle - wait for a condition without contributing to system load
     632             :  * @wq_head: the waitqueue to wait on
     633             :  * @condition: a C expression for the event to wait for
     634             :  *
     635             :  * The process is put to sleep (TASK_IDLE) until the
     636             :  * @condition evaluates to true.
     637             :  * The @condition is checked each time the waitqueue @wq_head is woken up.
     638             :  *
     639             :  * wake_up() has to be called after changing any variable that could
     640             :  * change the result of the wait condition.
     641             :  *
     642             :  */
     643             : #define wait_event_idle(wq_head, condition)                                     \
     644             : do {                                                                            \
     645             :         might_sleep();                                                          \
     646             :         if (!(condition))                                                       \
     647             :                 ___wait_event(wq_head, condition, TASK_IDLE, 0, 0, schedule()); \
     648             : } while (0)
     649             : 
     650             : /**
     651             :  * wait_event_idle_exclusive - wait for a condition with contributing to system load
     652             :  * @wq_head: the waitqueue to wait on
     653             :  * @condition: a C expression for the event to wait for
     654             :  *
     655             :  * The process is put to sleep (TASK_IDLE) until the
     656             :  * @condition evaluates to true.
     657             :  * The @condition is checked each time the waitqueue @wq_head is woken up.
     658             :  *
     659             :  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
     660             :  * set thus if other processes wait on the same list, when this
     661             :  * process is woken further processes are not considered.
     662             :  *
     663             :  * wake_up() has to be called after changing any variable that could
     664             :  * change the result of the wait condition.
     665             :  *
     666             :  */
     667             : #define wait_event_idle_exclusive(wq_head, condition)                           \
     668             : do {                                                                            \
     669             :         might_sleep();                                                          \
     670             :         if (!(condition))                                                       \
     671             :                 ___wait_event(wq_head, condition, TASK_IDLE, 1, 0, schedule()); \
     672             : } while (0)
     673             : 
     674             : #define __wait_event_idle_timeout(wq_head, condition, timeout)                  \
     675             :         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
     676             :                       TASK_IDLE, 0, timeout,                                    \
     677             :                       __ret = schedule_timeout(__ret))
     678             : 
     679             : /**
     680             :  * wait_event_idle_timeout - sleep without load until a condition becomes true or a timeout elapses
     681             :  * @wq_head: the waitqueue to wait on
     682             :  * @condition: a C expression for the event to wait for
     683             :  * @timeout: timeout, in jiffies
     684             :  *
     685             :  * The process is put to sleep (TASK_IDLE) until the
     686             :  * @condition evaluates to true. The @condition is checked each time
     687             :  * the waitqueue @wq_head is woken up.
     688             :  *
     689             :  * wake_up() has to be called after changing any variable that could
     690             :  * change the result of the wait condition.
     691             :  *
     692             :  * Returns:
     693             :  * 0 if the @condition evaluated to %false after the @timeout elapsed,
     694             :  * 1 if the @condition evaluated to %true after the @timeout elapsed,
     695             :  * or the remaining jiffies (at least 1) if the @condition evaluated
     696             :  * to %true before the @timeout elapsed.
     697             :  */
     698             : #define wait_event_idle_timeout(wq_head, condition, timeout)                    \
     699             : ({                                                                              \
     700             :         long __ret = timeout;                                                   \
     701             :         might_sleep();                                                          \
     702             :         if (!___wait_cond_timeout(condition))                                   \
     703             :                 __ret = __wait_event_idle_timeout(wq_head, condition, timeout); \
     704             :         __ret;                                                                  \
     705             : })
     706             : 
     707             : #define __wait_event_idle_exclusive_timeout(wq_head, condition, timeout)        \
     708             :         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
     709             :                       TASK_IDLE, 1, timeout,                                    \
     710             :                       __ret = schedule_timeout(__ret))
     711             : 
     712             : /**
     713             :  * wait_event_idle_exclusive_timeout - sleep without load until a condition becomes true or a timeout elapses
     714             :  * @wq_head: the waitqueue to wait on
     715             :  * @condition: a C expression for the event to wait for
     716             :  * @timeout: timeout, in jiffies
     717             :  *
     718             :  * The process is put to sleep (TASK_IDLE) until the
     719             :  * @condition evaluates to true. The @condition is checked each time
     720             :  * the waitqueue @wq_head is woken up.
     721             :  *
     722             :  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
     723             :  * set thus if other processes wait on the same list, when this
     724             :  * process is woken further processes are not considered.
     725             :  *
     726             :  * wake_up() has to be called after changing any variable that could
     727             :  * change the result of the wait condition.
     728             :  *
     729             :  * Returns:
     730             :  * 0 if the @condition evaluated to %false after the @timeout elapsed,
     731             :  * 1 if the @condition evaluated to %true after the @timeout elapsed,
     732             :  * or the remaining jiffies (at least 1) if the @condition evaluated
     733             :  * to %true before the @timeout elapsed.
     734             :  */
     735             : #define wait_event_idle_exclusive_timeout(wq_head, condition, timeout)          \
     736             : ({                                                                              \
     737             :         long __ret = timeout;                                                   \
     738             :         might_sleep();                                                          \
     739             :         if (!___wait_cond_timeout(condition))                                   \
     740             :                 __ret = __wait_event_idle_exclusive_timeout(wq_head, condition, timeout);\
     741             :         __ret;                                                                  \
     742             : })
     743             : 
     744             : extern int do_wait_intr(wait_queue_head_t *, wait_queue_entry_t *);
     745             : extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *);
     746             : 
     747             : #define __wait_event_interruptible_locked(wq, condition, exclusive, fn)         \
     748             : ({                                                                              \
     749             :         int __ret;                                                              \
     750             :         DEFINE_WAIT(__wait);                                                    \
     751             :         if (exclusive)                                                          \
     752             :                 __wait.flags |= WQ_FLAG_EXCLUSIVE;                              \
     753             :         do {                                                                    \
     754             :                 __ret = fn(&(wq), &__wait);                                     \
     755             :                 if (__ret)                                                      \
     756             :                         break;                                                  \
     757             :         } while (!(condition));                                                 \
     758             :         __remove_wait_queue(&(wq), &__wait);                                    \
     759             :         __set_current_state(TASK_RUNNING);                                      \
     760             :         __ret;                                                                  \
     761             : })
     762             : 
     763             : 
     764             : /**
     765             :  * wait_event_interruptible_locked - sleep until a condition gets true
     766             :  * @wq: the waitqueue to wait on
     767             :  * @condition: a C expression for the event to wait for
     768             :  *
     769             :  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
     770             :  * @condition evaluates to true or a signal is received.
     771             :  * The @condition is checked each time the waitqueue @wq is woken up.
     772             :  *
     773             :  * It must be called with wq.lock being held.  This spinlock is
     774             :  * unlocked while sleeping but @condition testing is done while lock
     775             :  * is held and when this macro exits the lock is held.
     776             :  *
     777             :  * The lock is locked/unlocked using spin_lock()/spin_unlock()
     778             :  * functions which must match the way they are locked/unlocked outside
     779             :  * of this macro.
     780             :  *
     781             :  * wake_up_locked() has to be called after changing any variable that could
     782             :  * change the result of the wait condition.
     783             :  *
     784             :  * The function will return -ERESTARTSYS if it was interrupted by a
     785             :  * signal and 0 if @condition evaluated to true.
     786             :  */
     787             : #define wait_event_interruptible_locked(wq, condition)                          \
     788             :         ((condition)                                                            \
     789             :          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr))
     790             : 
     791             : /**
     792             :  * wait_event_interruptible_locked_irq - sleep until a condition gets true
     793             :  * @wq: the waitqueue to wait on
     794             :  * @condition: a C expression for the event to wait for
     795             :  *
     796             :  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
     797             :  * @condition evaluates to true or a signal is received.
     798             :  * The @condition is checked each time the waitqueue @wq is woken up.
     799             :  *
     800             :  * It must be called with wq.lock being held.  This spinlock is
     801             :  * unlocked while sleeping but @condition testing is done while lock
     802             :  * is held and when this macro exits the lock is held.
     803             :  *
     804             :  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
     805             :  * functions which must match the way they are locked/unlocked outside
     806             :  * of this macro.
     807             :  *
     808             :  * wake_up_locked() has to be called after changing any variable that could
     809             :  * change the result of the wait condition.
     810             :  *
     811             :  * The function will return -ERESTARTSYS if it was interrupted by a
     812             :  * signal and 0 if @condition evaluated to true.
     813             :  */
     814             : #define wait_event_interruptible_locked_irq(wq, condition)                      \
     815             :         ((condition)                                                            \
     816             :          ? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr_irq))
     817             : 
     818             : /**
     819             :  * wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
     820             :  * @wq: the waitqueue to wait on
     821             :  * @condition: a C expression for the event to wait for
     822             :  *
     823             :  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
     824             :  * @condition evaluates to true or a signal is received.
     825             :  * The @condition is checked each time the waitqueue @wq is woken up.
     826             :  *
     827             :  * It must be called with wq.lock being held.  This spinlock is
     828             :  * unlocked while sleeping but @condition testing is done while lock
     829             :  * is held and when this macro exits the lock is held.
     830             :  *
     831             :  * The lock is locked/unlocked using spin_lock()/spin_unlock()
     832             :  * functions which must match the way they are locked/unlocked outside
     833             :  * of this macro.
     834             :  *
     835             :  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
     836             :  * set thus when other process waits process on the list if this
     837             :  * process is awaken further processes are not considered.
     838             :  *
     839             :  * wake_up_locked() has to be called after changing any variable that could
     840             :  * change the result of the wait condition.
     841             :  *
     842             :  * The function will return -ERESTARTSYS if it was interrupted by a
     843             :  * signal and 0 if @condition evaluated to true.
     844             :  */
     845             : #define wait_event_interruptible_exclusive_locked(wq, condition)                \
     846             :         ((condition)                                                            \
     847             :          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr))
     848             : 
     849             : /**
     850             :  * wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
     851             :  * @wq: the waitqueue to wait on
     852             :  * @condition: a C expression for the event to wait for
     853             :  *
     854             :  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
     855             :  * @condition evaluates to true or a signal is received.
     856             :  * The @condition is checked each time the waitqueue @wq is woken up.
     857             :  *
     858             :  * It must be called with wq.lock being held.  This spinlock is
     859             :  * unlocked while sleeping but @condition testing is done while lock
     860             :  * is held and when this macro exits the lock is held.
     861             :  *
     862             :  * The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
     863             :  * functions which must match the way they are locked/unlocked outside
     864             :  * of this macro.
     865             :  *
     866             :  * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
     867             :  * set thus when other process waits process on the list if this
     868             :  * process is awaken further processes are not considered.
     869             :  *
     870             :  * wake_up_locked() has to be called after changing any variable that could
     871             :  * change the result of the wait condition.
     872             :  *
     873             :  * The function will return -ERESTARTSYS if it was interrupted by a
     874             :  * signal and 0 if @condition evaluated to true.
     875             :  */
     876             : #define wait_event_interruptible_exclusive_locked_irq(wq, condition)            \
     877             :         ((condition)                                                            \
     878             :          ? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr_irq))
     879             : 
     880             : 
     881             : #define __wait_event_killable(wq, condition)                                    \
     882             :         ___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
     883             : 
     884             : /**
     885             :  * wait_event_killable - sleep until a condition gets true
     886             :  * @wq_head: the waitqueue to wait on
     887             :  * @condition: a C expression for the event to wait for
     888             :  *
     889             :  * The process is put to sleep (TASK_KILLABLE) until the
     890             :  * @condition evaluates to true or a signal is received.
     891             :  * The @condition is checked each time the waitqueue @wq_head is woken up.
     892             :  *
     893             :  * wake_up() has to be called after changing any variable that could
     894             :  * change the result of the wait condition.
     895             :  *
     896             :  * The function will return -ERESTARTSYS if it was interrupted by a
     897             :  * signal and 0 if @condition evaluated to true.
     898             :  */
     899             : #define wait_event_killable(wq_head, condition)                                 \
     900             : ({                                                                              \
     901             :         int __ret = 0;                                                          \
     902             :         might_sleep();                                                          \
     903             :         if (!(condition))                                                       \
     904             :                 __ret = __wait_event_killable(wq_head, condition);              \
     905             :         __ret;                                                                  \
     906             : })
     907             : 
     908             : #define __wait_event_killable_timeout(wq_head, condition, timeout)              \
     909             :         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
     910             :                       TASK_KILLABLE, 0, timeout,                                \
     911             :                       __ret = schedule_timeout(__ret))
     912             : 
     913             : /**
     914             :  * wait_event_killable_timeout - sleep until a condition gets true or a timeout elapses
     915             :  * @wq_head: the waitqueue to wait on
     916             :  * @condition: a C expression for the event to wait for
     917             :  * @timeout: timeout, in jiffies
     918             :  *
     919             :  * The process is put to sleep (TASK_KILLABLE) until the
     920             :  * @condition evaluates to true or a kill signal is received.
     921             :  * The @condition is checked each time the waitqueue @wq_head is woken up.
     922             :  *
     923             :  * wake_up() has to be called after changing any variable that could
     924             :  * change the result of the wait condition.
     925             :  *
     926             :  * Returns:
     927             :  * 0 if the @condition evaluated to %false after the @timeout elapsed,
     928             :  * 1 if the @condition evaluated to %true after the @timeout elapsed,
     929             :  * the remaining jiffies (at least 1) if the @condition evaluated
     930             :  * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
     931             :  * interrupted by a kill signal.
     932             :  *
     933             :  * Only kill signals interrupt this process.
     934             :  */
     935             : #define wait_event_killable_timeout(wq_head, condition, timeout)                \
     936             : ({                                                                              \
     937             :         long __ret = timeout;                                                   \
     938             :         might_sleep();                                                          \
     939             :         if (!___wait_cond_timeout(condition))                                   \
     940             :                 __ret = __wait_event_killable_timeout(wq_head,                  \
     941             :                                                 condition, timeout);            \
     942             :         __ret;                                                                  \
     943             : })
     944             : 
     945             : 
     946             : #define __wait_event_lock_irq(wq_head, condition, lock, cmd)                    \
     947             :         (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0,     \
     948             :                             spin_unlock_irq(&lock);                         \
     949             :                             cmd;                                                \
     950             :                             schedule();                                         \
     951             :                             spin_lock_irq(&lock))
     952             : 
     953             : /**
     954             :  * wait_event_lock_irq_cmd - sleep until a condition gets true. The
     955             :  *                           condition is checked under the lock. This
     956             :  *                           is expected to be called with the lock
     957             :  *                           taken.
     958             :  * @wq_head: the waitqueue to wait on
     959             :  * @condition: a C expression for the event to wait for
     960             :  * @lock: a locked spinlock_t, which will be released before cmd
     961             :  *        and schedule() and reacquired afterwards.
     962             :  * @cmd: a command which is invoked outside the critical section before
     963             :  *       sleep
     964             :  *
     965             :  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
     966             :  * @condition evaluates to true. The @condition is checked each time
     967             :  * the waitqueue @wq_head is woken up.
     968             :  *
     969             :  * wake_up() has to be called after changing any variable that could
     970             :  * change the result of the wait condition.
     971             :  *
     972             :  * This is supposed to be called while holding the lock. The lock is
     973             :  * dropped before invoking the cmd and going to sleep and is reacquired
     974             :  * afterwards.
     975             :  */
     976             : #define wait_event_lock_irq_cmd(wq_head, condition, lock, cmd)                  \
     977             : do {                                                                            \
     978             :         if (condition)                                                          \
     979             :                 break;                                                          \
     980             :         __wait_event_lock_irq(wq_head, condition, lock, cmd);                   \
     981             : } while (0)
     982             : 
     983             : /**
     984             :  * wait_event_lock_irq - sleep until a condition gets true. The
     985             :  *                       condition is checked under the lock. This
     986             :  *                       is expected to be called with the lock
     987             :  *                       taken.
     988             :  * @wq_head: the waitqueue to wait on
     989             :  * @condition: a C expression for the event to wait for
     990             :  * @lock: a locked spinlock_t, which will be released before schedule()
     991             :  *        and reacquired afterwards.
     992             :  *
     993             :  * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
     994             :  * @condition evaluates to true. The @condition is checked each time
     995             :  * the waitqueue @wq_head is woken up.
     996             :  *
     997             :  * wake_up() has to be called after changing any variable that could
     998             :  * change the result of the wait condition.
     999             :  *
    1000             :  * This is supposed to be called while holding the lock. The lock is
    1001             :  * dropped before going to sleep and is reacquired afterwards.
    1002             :  */
    1003             : #define wait_event_lock_irq(wq_head, condition, lock)                           \
    1004             : do {                                                                            \
    1005             :         if (condition)                                                          \
    1006             :                 break;                                                          \
    1007             :         __wait_event_lock_irq(wq_head, condition, lock, );                      \
    1008             : } while (0)
    1009             : 
    1010             : 
    1011             : #define __wait_event_interruptible_lock_irq(wq_head, condition, lock, cmd)      \
    1012             :         ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0,             \
    1013             :                       spin_unlock_irq(&lock);                                       \
    1014             :                       cmd;                                                      \
    1015             :                       schedule();                                               \
    1016             :                       spin_lock_irq(&lock))
    1017             : 
    1018             : /**
    1019             :  * wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
    1020             :  *              The condition is checked under the lock. This is expected to
    1021             :  *              be called with the lock taken.
    1022             :  * @wq_head: the waitqueue to wait on
    1023             :  * @condition: a C expression for the event to wait for
    1024             :  * @lock: a locked spinlock_t, which will be released before cmd and
    1025             :  *        schedule() and reacquired afterwards.
    1026             :  * @cmd: a command which is invoked outside the critical section before
    1027             :  *       sleep
    1028             :  *
    1029             :  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
    1030             :  * @condition evaluates to true or a signal is received. The @condition is
    1031             :  * checked each time the waitqueue @wq_head is woken up.
    1032             :  *
    1033             :  * wake_up() has to be called after changing any variable that could
    1034             :  * change the result of the wait condition.
    1035             :  *
    1036             :  * This is supposed to be called while holding the lock. The lock is
    1037             :  * dropped before invoking the cmd and going to sleep and is reacquired
    1038             :  * afterwards.
    1039             :  *
    1040             :  * The macro will return -ERESTARTSYS if it was interrupted by a signal
    1041             :  * and 0 if @condition evaluated to true.
    1042             :  */
    1043             : #define wait_event_interruptible_lock_irq_cmd(wq_head, condition, lock, cmd)    \
    1044             : ({                                                                              \
    1045             :         int __ret = 0;                                                          \
    1046             :         if (!(condition))                                                       \
    1047             :                 __ret = __wait_event_interruptible_lock_irq(wq_head,            \
    1048             :                                                 condition, lock, cmd);          \
    1049             :         __ret;                                                                  \
    1050             : })
    1051             : 
    1052             : /**
    1053             :  * wait_event_interruptible_lock_irq - sleep until a condition gets true.
    1054             :  *              The condition is checked under the lock. This is expected
    1055             :  *              to be called with the lock taken.
    1056             :  * @wq_head: the waitqueue to wait on
    1057             :  * @condition: a C expression for the event to wait for
    1058             :  * @lock: a locked spinlock_t, which will be released before schedule()
    1059             :  *        and reacquired afterwards.
    1060             :  *
    1061             :  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
    1062             :  * @condition evaluates to true or signal is received. The @condition is
    1063             :  * checked each time the waitqueue @wq_head is woken up.
    1064             :  *
    1065             :  * wake_up() has to be called after changing any variable that could
    1066             :  * change the result of the wait condition.
    1067             :  *
    1068             :  * This is supposed to be called while holding the lock. The lock is
    1069             :  * dropped before going to sleep and is reacquired afterwards.
    1070             :  *
    1071             :  * The macro will return -ERESTARTSYS if it was interrupted by a signal
    1072             :  * and 0 if @condition evaluated to true.
    1073             :  */
    1074             : #define wait_event_interruptible_lock_irq(wq_head, condition, lock)             \
    1075             : ({                                                                              \
    1076             :         int __ret = 0;                                                          \
    1077             :         if (!(condition))                                                       \
    1078             :                 __ret = __wait_event_interruptible_lock_irq(wq_head,            \
    1079             :                                                 condition, lock,);              \
    1080             :         __ret;                                                                  \
    1081             : })
    1082             : 
    1083             : #define __wait_event_lock_irq_timeout(wq_head, condition, lock, timeout, state) \
    1084             :         ___wait_event(wq_head, ___wait_cond_timeout(condition),                 \
    1085             :                       state, 0, timeout,                                        \
    1086             :                       spin_unlock_irq(&lock);                                       \
    1087             :                       __ret = schedule_timeout(__ret);                          \
    1088             :                       spin_lock_irq(&lock));
    1089             : 
    1090             : /**
    1091             :  * wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
    1092             :  *              true or a timeout elapses. The condition is checked under
    1093             :  *              the lock. This is expected to be called with the lock taken.
    1094             :  * @wq_head: the waitqueue to wait on
    1095             :  * @condition: a C expression for the event to wait for
    1096             :  * @lock: a locked spinlock_t, which will be released before schedule()
    1097             :  *        and reacquired afterwards.
    1098             :  * @timeout: timeout, in jiffies
    1099             :  *
    1100             :  * The process is put to sleep (TASK_INTERRUPTIBLE) until the
    1101             :  * @condition evaluates to true or signal is received. The @condition is
    1102             :  * checked each time the waitqueue @wq_head is woken up.
    1103             :  *
    1104             :  * wake_up() has to be called after changing any variable that could
    1105             :  * change the result of the wait condition.
    1106             :  *
    1107             :  * This is supposed to be called while holding the lock. The lock is
    1108             :  * dropped before going to sleep and is reacquired afterwards.
    1109             :  *
    1110             :  * The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
    1111             :  * was interrupted by a signal, and the remaining jiffies otherwise
    1112             :  * if the condition evaluated to true before the timeout elapsed.
    1113             :  */
    1114             : #define wait_event_interruptible_lock_irq_timeout(wq_head, condition, lock,     \
    1115             :                                                   timeout)                      \
    1116             : ({                                                                              \
    1117             :         long __ret = timeout;                                                   \
    1118             :         if (!___wait_cond_timeout(condition))                                   \
    1119             :                 __ret = __wait_event_lock_irq_timeout(                          \
    1120             :                                         wq_head, condition, lock, timeout,      \
    1121             :                                         TASK_INTERRUPTIBLE);                    \
    1122             :         __ret;                                                                  \
    1123             : })
    1124             : 
    1125             : #define wait_event_lock_irq_timeout(wq_head, condition, lock, timeout)          \
    1126             : ({                                                                              \
    1127             :         long __ret = timeout;                                                   \
    1128             :         if (!___wait_cond_timeout(condition))                                   \
    1129             :                 __ret = __wait_event_lock_irq_timeout(                          \
    1130             :                                         wq_head, condition, lock, timeout,      \
    1131             :                                         TASK_UNINTERRUPTIBLE);                  \
    1132             :         __ret;                                                                  \
    1133             : })
    1134             : 
    1135             : /*
    1136             :  * Waitqueues which are removed from the waitqueue_head at wakeup time
    1137             :  */
    1138             : void prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
    1139             : void prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
    1140             : long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
    1141             : void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
    1142             : long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout);
    1143             : int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
    1144             : int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
    1145             : 
    1146             : #define DEFINE_WAIT_FUNC(name, function)                                        \
    1147             :         struct wait_queue_entry name = {                                        \
    1148             :                 .private        = current,                                      \
    1149             :                 .func           = function,                                     \
    1150             :                 .entry          = LIST_HEAD_INIT((name).entry),                 \
    1151             :         }
    1152             : 
    1153             : #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
    1154             : 
    1155             : #define init_wait(wait)                                                         \
    1156             :         do {                                                                    \
    1157             :                 (wait)->private = current;                                   \
    1158             :                 (wait)->func = autoremove_wake_function;                     \
    1159             :                 INIT_LIST_HEAD(&(wait)->entry);                                  \
    1160             :                 (wait)->flags = 0;                                           \
    1161             :         } while (0)
    1162             : 
    1163             : bool try_invoke_on_locked_down_task(struct task_struct *p, bool (*func)(struct task_struct *t, void *arg), void *arg);
    1164             : 
    1165             : #endif /* _LINUX_WAIT_H */

Generated by: LCOV version 1.14