1223 строки
41 KiB
C
1223 строки
41 KiB
C
#ifndef _LINUX_WAIT_H
|
|
#define _LINUX_WAIT_H
|
|
/*
|
|
* Linux wait queue related types and methods
|
|
*/
|
|
#include <linux/list.h>
|
|
#include <linux/stddef.h>
|
|
#include <linux/spinlock.h>
|
|
#include <asm/current.h>
|
|
#include <uapi/linux/wait.h>
|
|
|
|
typedef struct __wait_queue wait_queue_t;
|
|
typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key);
|
|
int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, void *key);
|
|
|
|
/* __wait_queue::flags */
|
|
#define WQ_FLAG_EXCLUSIVE 0x01
|
|
#define WQ_FLAG_WOKEN 0x02
|
|
|
|
struct __wait_queue {
|
|
unsigned int flags;
|
|
void *private;
|
|
wait_queue_func_t func;
|
|
struct list_head task_list;
|
|
};
|
|
|
|
struct wait_bit_key {
|
|
void *flags;
|
|
int bit_nr;
|
|
#define WAIT_ATOMIC_T_BIT_NR -1
|
|
unsigned long timeout;
|
|
};
|
|
|
|
struct wait_bit_queue {
|
|
struct wait_bit_key key;
|
|
wait_queue_t wait;
|
|
};
|
|
|
|
struct __wait_queue_head {
|
|
spinlock_t lock;
|
|
struct list_head task_list;
|
|
};
|
|
typedef struct __wait_queue_head wait_queue_head_t;
|
|
|
|
struct task_struct;
|
|
|
|
/*
|
|
* Macros for declaration and initialisaton of the datatypes
|
|
*/
|
|
|
|
#define __WAITQUEUE_INITIALIZER(name, tsk) { \
|
|
.private = tsk, \
|
|
.func = default_wake_function, \
|
|
.task_list = { NULL, NULL } }
|
|
|
|
#define DECLARE_WAITQUEUE(name, tsk) \
|
|
wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk)
|
|
|
|
#define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \
|
|
.lock = __SPIN_LOCK_UNLOCKED(name.lock), \
|
|
.task_list = { &(name).task_list, &(name).task_list } }
|
|
|
|
#define DECLARE_WAIT_QUEUE_HEAD(name) \
|
|
wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
|
|
|
|
#define __WAIT_BIT_KEY_INITIALIZER(word, bit) \
|
|
{ .flags = word, .bit_nr = bit, }
|
|
|
|
#define __WAIT_ATOMIC_T_KEY_INITIALIZER(p) \
|
|
{ .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }
|
|
|
|
extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *);
|
|
|
|
#define init_waitqueue_head(q) \
|
|
do { \
|
|
static struct lock_class_key __key; \
|
|
\
|
|
__init_waitqueue_head((q), #q, &__key); \
|
|
} while (0)
|
|
|
|
#ifdef CONFIG_LOCKDEP
|
|
# define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
|
|
({ init_waitqueue_head(&name); name; })
|
|
# define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
|
|
wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
|
|
#else
|
|
# define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
|
|
#endif
|
|
|
|
static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
|
|
{
|
|
q->flags = 0;
|
|
q->private = p;
|
|
q->func = default_wake_function;
|
|
}
|
|
|
|
static inline void
|
|
init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func)
|
|
{
|
|
q->flags = 0;
|
|
q->private = NULL;
|
|
q->func = func;
|
|
}
|
|
|
|
/**
|
|
* waitqueue_active -- locklessly test for waiters on the queue
|
|
* @q: the waitqueue to test for waiters
|
|
*
|
|
* returns true if the wait list is not empty
|
|
*
|
|
* NOTE: this function is lockless and requires care, incorrect usage _will_
|
|
* lead to sporadic and non-obvious failure.
|
|
*
|
|
* Use either while holding wait_queue_head_t::lock or when used for wakeups
|
|
* with an extra smp_mb() like:
|
|
*
|
|
* CPU0 - waker CPU1 - waiter
|
|
*
|
|
* for (;;) {
|
|
* @cond = true; prepare_to_wait(&wq, &wait, state);
|
|
* smp_mb(); // smp_mb() from set_current_state()
|
|
* if (waitqueue_active(wq)) if (@cond)
|
|
* wake_up(wq); break;
|
|
* schedule();
|
|
* }
|
|
* finish_wait(&wq, &wait);
|
|
*
|
|
* Because without the explicit smp_mb() it's possible for the
|
|
* waitqueue_active() load to get hoisted over the @cond store such that we'll
|
|
* observe an empty wait list while the waiter might not observe @cond.
|
|
*
|
|
* Also note that this 'optimization' trades a spin_lock() for an smp_mb(),
|
|
* which (when the lock is uncontended) are of roughly equal cost.
|
|
*/
|
|
static inline int waitqueue_active(wait_queue_head_t *q)
|
|
{
|
|
return !list_empty(&q->task_list);
|
|
}
|
|
|
|
/**
|
|
* wq_has_sleeper - check if there are any waiting processes
|
|
* @wq: wait queue head
|
|
*
|
|
* Returns true if wq has waiting processes
|
|
*
|
|
* Please refer to the comment for waitqueue_active.
|
|
*/
|
|
static inline bool wq_has_sleeper(wait_queue_head_t *wq)
|
|
{
|
|
/*
|
|
* We need to be sure we are in sync with the
|
|
* add_wait_queue modifications to the wait queue.
|
|
*
|
|
* This memory barrier should be paired with one on the
|
|
* waiting side.
|
|
*/
|
|
smp_mb();
|
|
return waitqueue_active(wq);
|
|
}
|
|
|
|
extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
|
|
extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
|
|
extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
|
|
|
|
static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
|
|
{
|
|
list_add(&new->task_list, &head->task_list);
|
|
}
|
|
|
|
/*
|
|
* Used for wake-one threads:
|
|
*/
|
|
static inline void
|
|
__add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
|
|
{
|
|
wait->flags |= WQ_FLAG_EXCLUSIVE;
|
|
__add_wait_queue(q, wait);
|
|
}
|
|
|
|
static inline void __add_wait_queue_tail(wait_queue_head_t *head,
|
|
wait_queue_t *new)
|
|
{
|
|
list_add_tail(&new->task_list, &head->task_list);
|
|
}
|
|
|
|
static inline void
|
|
__add_wait_queue_tail_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
|
|
{
|
|
wait->flags |= WQ_FLAG_EXCLUSIVE;
|
|
__add_wait_queue_tail(q, wait);
|
|
}
|
|
|
|
static inline void
|
|
__remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old)
|
|
{
|
|
list_del(&old->task_list);
|
|
}
|
|
|
|
typedef int wait_bit_action_f(struct wait_bit_key *, int mode);
|
|
void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
|
|
void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
|
|
void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
|
|
void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr);
|
|
void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
|
|
void __wake_up_bit(wait_queue_head_t *, void *, int);
|
|
int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
|
|
int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned);
|
|
void wake_up_bit(void *, int);
|
|
void wake_up_atomic_t(atomic_t *);
|
|
int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned);
|
|
int out_of_line_wait_on_bit_timeout(void *, int, wait_bit_action_f *, unsigned, unsigned long);
|
|
int out_of_line_wait_on_bit_lock(void *, int, wait_bit_action_f *, unsigned);
|
|
int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned);
|
|
wait_queue_head_t *bit_waitqueue(void *, int);
|
|
|
|
#define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL)
|
|
#define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL)
|
|
#define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL)
|
|
#define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL, 1)
|
|
#define wake_up_all_locked(x) __wake_up_locked((x), TASK_NORMAL, 0)
|
|
|
|
#define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
|
|
#define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
|
|
#define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
|
|
#define wake_up_interruptible_sync(x) __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
|
|
|
|
/*
|
|
* Wakeup macros to be used to report events to the targets.
|
|
*/
|
|
#define wake_up_poll(x, m) \
|
|
__wake_up(x, TASK_NORMAL, 1, (void *) (m))
|
|
#define wake_up_locked_poll(x, m) \
|
|
__wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
|
|
#define wake_up_interruptible_poll(x, m) \
|
|
__wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
|
|
#define wake_up_interruptible_sync_poll(x, m) \
|
|
__wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
|
|
|
|
#define ___wait_cond_timeout(condition) \
|
|
({ \
|
|
bool __cond = (condition); \
|
|
if (__cond && !__ret) \
|
|
__ret = 1; \
|
|
__cond || !__ret; \
|
|
})
|
|
|
|
#define ___wait_is_interruptible(state) \
|
|
(!__builtin_constant_p(state) || \
|
|
state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE) \
|
|
|
|
/*
|
|
* The below macro ___wait_event() has an explicit shadow of the __ret
|
|
* variable when used from the wait_event_*() macros.
|
|
*
|
|
* This is so that both can use the ___wait_cond_timeout() construct
|
|
* to wrap the condition.
|
|
*
|
|
* The type inconsistency of the wait_event_*() __ret variable is also
|
|
* on purpose; we use long where we can return timeout values and int
|
|
* otherwise.
|
|
*/
|
|
|
|
#define ___wait_event(wq, condition, state, exclusive, ret, cmd) \
|
|
({ \
|
|
__label__ __out; \
|
|
wait_queue_t __wait; \
|
|
long __ret = ret; /* explicit shadow */ \
|
|
\
|
|
INIT_LIST_HEAD(&__wait.task_list); \
|
|
if (exclusive) \
|
|
__wait.flags = WQ_FLAG_EXCLUSIVE; \
|
|
else \
|
|
__wait.flags = 0; \
|
|
\
|
|
for (;;) { \
|
|
long __int = prepare_to_wait_event(&wq, &__wait, state);\
|
|
\
|
|
if (condition) \
|
|
break; \
|
|
\
|
|
if (___wait_is_interruptible(state) && __int) { \
|
|
__ret = __int; \
|
|
if (exclusive) { \
|
|
abort_exclusive_wait(&wq, &__wait, \
|
|
state, NULL); \
|
|
goto __out; \
|
|
} \
|
|
break; \
|
|
} \
|
|
\
|
|
cmd; \
|
|
} \
|
|
finish_wait(&wq, &__wait); \
|
|
__out: __ret; \
|
|
})
|
|
|
|
#define __wait_event(wq, condition) \
|
|
(void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
|
|
schedule())
|
|
|
|
/**
|
|
* wait_event - sleep until a condition gets true
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
*
|
|
* The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
|
|
* @condition evaluates to true. The @condition is checked each time
|
|
* the waitqueue @wq is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*/
|
|
#define wait_event(wq, condition) \
|
|
do { \
|
|
might_sleep(); \
|
|
if (condition) \
|
|
break; \
|
|
__wait_event(wq, condition); \
|
|
} while (0)
|
|
|
|
#define __io_wait_event(wq, condition) \
|
|
(void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
|
|
io_schedule())
|
|
|
|
/*
|
|
* io_wait_event() -- like wait_event() but with io_schedule()
|
|
*/
|
|
#define io_wait_event(wq, condition) \
|
|
do { \
|
|
might_sleep(); \
|
|
if (condition) \
|
|
break; \
|
|
__io_wait_event(wq, condition); \
|
|
} while (0)
|
|
|
|
#define __wait_event_freezable(wq, condition) \
|
|
___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \
|
|
schedule(); try_to_freeze())
|
|
|
|
/**
|
|
* wait_event_freezable - sleep (or freeze) until a condition gets true
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
|
|
* to system load) until the @condition evaluates to true. The
|
|
* @condition is checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*/
|
|
#define wait_event_freezable(wq, condition) \
|
|
({ \
|
|
int __ret = 0; \
|
|
might_sleep(); \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_freezable(wq, condition); \
|
|
__ret; \
|
|
})
|
|
|
|
#define __wait_event_timeout(wq, condition, timeout) \
|
|
___wait_event(wq, ___wait_cond_timeout(condition), \
|
|
TASK_UNINTERRUPTIBLE, 0, timeout, \
|
|
__ret = schedule_timeout(__ret))
|
|
|
|
/**
|
|
* wait_event_timeout - sleep until a condition gets true or a timeout elapses
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @timeout: timeout, in jiffies
|
|
*
|
|
* The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
|
|
* @condition evaluates to true. The @condition is checked each time
|
|
* the waitqueue @wq is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* Returns:
|
|
* 0 if the @condition evaluated to %false after the @timeout elapsed,
|
|
* 1 if the @condition evaluated to %true after the @timeout elapsed,
|
|
* or the remaining jiffies (at least 1) if the @condition evaluated
|
|
* to %true before the @timeout elapsed.
|
|
*/
|
|
#define wait_event_timeout(wq, condition, timeout) \
|
|
({ \
|
|
long __ret = timeout; \
|
|
might_sleep(); \
|
|
if (!___wait_cond_timeout(condition)) \
|
|
__ret = __wait_event_timeout(wq, condition, timeout); \
|
|
__ret; \
|
|
})
|
|
|
|
#define __wait_event_freezable_timeout(wq, condition, timeout) \
|
|
___wait_event(wq, ___wait_cond_timeout(condition), \
|
|
TASK_INTERRUPTIBLE, 0, timeout, \
|
|
__ret = schedule_timeout(__ret); try_to_freeze())
|
|
|
|
/*
|
|
* like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
|
|
* increasing load and is freezable.
|
|
*/
|
|
#define wait_event_freezable_timeout(wq, condition, timeout) \
|
|
({ \
|
|
long __ret = timeout; \
|
|
might_sleep(); \
|
|
if (!___wait_cond_timeout(condition)) \
|
|
__ret = __wait_event_freezable_timeout(wq, condition, timeout); \
|
|
__ret; \
|
|
})
|
|
|
|
#define __wait_event_exclusive_cmd(wq, condition, cmd1, cmd2) \
|
|
(void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 1, 0, \
|
|
cmd1; schedule(); cmd2)
|
|
/*
|
|
* Just like wait_event_cmd(), except it sets exclusive flag
|
|
*/
|
|
#define wait_event_exclusive_cmd(wq, condition, cmd1, cmd2) \
|
|
do { \
|
|
if (condition) \
|
|
break; \
|
|
__wait_event_exclusive_cmd(wq, condition, cmd1, cmd2); \
|
|
} while (0)
|
|
|
|
#define __wait_event_cmd(wq, condition, cmd1, cmd2) \
|
|
(void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
|
|
cmd1; schedule(); cmd2)
|
|
|
|
/**
|
|
* wait_event_cmd - sleep until a condition gets true
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @cmd1: the command will be executed before sleep
|
|
* @cmd2: the command will be executed after sleep
|
|
*
|
|
* The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
|
|
* @condition evaluates to true. The @condition is checked each time
|
|
* the waitqueue @wq is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*/
|
|
#define wait_event_cmd(wq, condition, cmd1, cmd2) \
|
|
do { \
|
|
if (condition) \
|
|
break; \
|
|
__wait_event_cmd(wq, condition, cmd1, cmd2); \
|
|
} while (0)
|
|
|
|
#define __wait_event_interruptible(wq, condition) \
|
|
___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \
|
|
schedule())
|
|
|
|
/**
|
|
* wait_event_interruptible - sleep until a condition gets true
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* The function will return -ERESTARTSYS if it was interrupted by a
|
|
* signal and 0 if @condition evaluated to true.
|
|
*/
|
|
#define wait_event_interruptible(wq, condition) \
|
|
({ \
|
|
int __ret = 0; \
|
|
might_sleep(); \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_interruptible(wq, condition); \
|
|
__ret; \
|
|
})
|
|
|
|
#define __wait_event_interruptible_timeout(wq, condition, timeout) \
|
|
___wait_event(wq, ___wait_cond_timeout(condition), \
|
|
TASK_INTERRUPTIBLE, 0, timeout, \
|
|
__ret = schedule_timeout(__ret))
|
|
|
|
/**
|
|
* wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @timeout: timeout, in jiffies
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* Returns:
|
|
* 0 if the @condition evaluated to %false after the @timeout elapsed,
|
|
* 1 if the @condition evaluated to %true after the @timeout elapsed,
|
|
* the remaining jiffies (at least 1) if the @condition evaluated
|
|
* to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
|
|
* interrupted by a signal.
|
|
*/
|
|
#define wait_event_interruptible_timeout(wq, condition, timeout) \
|
|
({ \
|
|
long __ret = timeout; \
|
|
might_sleep(); \
|
|
if (!___wait_cond_timeout(condition)) \
|
|
__ret = __wait_event_interruptible_timeout(wq, \
|
|
condition, timeout); \
|
|
__ret; \
|
|
})
|
|
|
|
#define __wait_event_hrtimeout(wq, condition, timeout, state) \
|
|
({ \
|
|
int __ret = 0; \
|
|
struct hrtimer_sleeper __t; \
|
|
\
|
|
hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC, \
|
|
HRTIMER_MODE_REL); \
|
|
hrtimer_init_sleeper(&__t, current); \
|
|
if ((timeout).tv64 != KTIME_MAX) \
|
|
hrtimer_start_range_ns(&__t.timer, timeout, \
|
|
current->timer_slack_ns, \
|
|
HRTIMER_MODE_REL); \
|
|
\
|
|
__ret = ___wait_event(wq, condition, state, 0, 0, \
|
|
if (!__t.task) { \
|
|
__ret = -ETIME; \
|
|
break; \
|
|
} \
|
|
schedule()); \
|
|
\
|
|
hrtimer_cancel(&__t.timer); \
|
|
destroy_hrtimer_on_stack(&__t.timer); \
|
|
__ret; \
|
|
})
|
|
|
|
/**
|
|
* wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @timeout: timeout, as a ktime_t
|
|
*
|
|
* The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* The function returns 0 if @condition became true, or -ETIME if the timeout
|
|
* elapsed.
|
|
*/
|
|
#define wait_event_hrtimeout(wq, condition, timeout) \
|
|
({ \
|
|
int __ret = 0; \
|
|
might_sleep(); \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_hrtimeout(wq, condition, timeout, \
|
|
TASK_UNINTERRUPTIBLE); \
|
|
__ret; \
|
|
})
|
|
|
|
/**
|
|
* wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @timeout: timeout, as a ktime_t
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* The function returns 0 if @condition became true, -ERESTARTSYS if it was
|
|
* interrupted by a signal, or -ETIME if the timeout elapsed.
|
|
*/
|
|
#define wait_event_interruptible_hrtimeout(wq, condition, timeout) \
|
|
({ \
|
|
long __ret = 0; \
|
|
might_sleep(); \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_hrtimeout(wq, condition, timeout, \
|
|
TASK_INTERRUPTIBLE); \
|
|
__ret; \
|
|
})
|
|
|
|
#define __wait_event_interruptible_exclusive(wq, condition) \
|
|
___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \
|
|
schedule())
|
|
|
|
#define wait_event_interruptible_exclusive(wq, condition) \
|
|
({ \
|
|
int __ret = 0; \
|
|
might_sleep(); \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_interruptible_exclusive(wq, condition);\
|
|
__ret; \
|
|
})
|
|
|
|
|
|
#define __wait_event_freezable_exclusive(wq, condition) \
|
|
___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \
|
|
schedule(); try_to_freeze())
|
|
|
|
#define wait_event_freezable_exclusive(wq, condition) \
|
|
({ \
|
|
int __ret = 0; \
|
|
might_sleep(); \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_freezable_exclusive(wq, condition);\
|
|
__ret; \
|
|
})
|
|
|
|
|
|
#define __wait_event_interruptible_locked(wq, condition, exclusive, irq) \
|
|
({ \
|
|
int __ret = 0; \
|
|
DEFINE_WAIT(__wait); \
|
|
if (exclusive) \
|
|
__wait.flags |= WQ_FLAG_EXCLUSIVE; \
|
|
do { \
|
|
if (likely(list_empty(&__wait.task_list))) \
|
|
__add_wait_queue_tail(&(wq), &__wait); \
|
|
set_current_state(TASK_INTERRUPTIBLE); \
|
|
if (signal_pending(current)) { \
|
|
__ret = -ERESTARTSYS; \
|
|
break; \
|
|
} \
|
|
if (irq) \
|
|
spin_unlock_irq(&(wq).lock); \
|
|
else \
|
|
spin_unlock(&(wq).lock); \
|
|
schedule(); \
|
|
if (irq) \
|
|
spin_lock_irq(&(wq).lock); \
|
|
else \
|
|
spin_lock(&(wq).lock); \
|
|
} while (!(condition)); \
|
|
__remove_wait_queue(&(wq), &__wait); \
|
|
__set_current_state(TASK_RUNNING); \
|
|
__ret; \
|
|
})
|
|
|
|
|
|
/**
|
|
* wait_event_interruptible_locked - sleep until a condition gets true
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* It must be called with wq.lock being held. This spinlock is
|
|
* unlocked while sleeping but @condition testing is done while lock
|
|
* is held and when this macro exits the lock is held.
|
|
*
|
|
* The lock is locked/unlocked using spin_lock()/spin_unlock()
|
|
* functions which must match the way they are locked/unlocked outside
|
|
* of this macro.
|
|
*
|
|
* wake_up_locked() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* The function will return -ERESTARTSYS if it was interrupted by a
|
|
* signal and 0 if @condition evaluated to true.
|
|
*/
|
|
#define wait_event_interruptible_locked(wq, condition) \
|
|
((condition) \
|
|
? 0 : __wait_event_interruptible_locked(wq, condition, 0, 0))
|
|
|
|
/**
|
|
* wait_event_interruptible_locked_irq - sleep until a condition gets true
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* It must be called with wq.lock being held. This spinlock is
|
|
* unlocked while sleeping but @condition testing is done while lock
|
|
* is held and when this macro exits the lock is held.
|
|
*
|
|
* The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
|
|
* functions which must match the way they are locked/unlocked outside
|
|
* of this macro.
|
|
*
|
|
* wake_up_locked() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* The function will return -ERESTARTSYS if it was interrupted by a
|
|
* signal and 0 if @condition evaluated to true.
|
|
*/
|
|
#define wait_event_interruptible_locked_irq(wq, condition) \
|
|
((condition) \
|
|
? 0 : __wait_event_interruptible_locked(wq, condition, 0, 1))
|
|
|
|
/**
|
|
* wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* It must be called with wq.lock being held. This spinlock is
|
|
* unlocked while sleeping but @condition testing is done while lock
|
|
* is held and when this macro exits the lock is held.
|
|
*
|
|
* The lock is locked/unlocked using spin_lock()/spin_unlock()
|
|
* functions which must match the way they are locked/unlocked outside
|
|
* of this macro.
|
|
*
|
|
* The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
|
|
* set thus when other process waits process on the list if this
|
|
* process is awaken further processes are not considered.
|
|
*
|
|
* wake_up_locked() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* The function will return -ERESTARTSYS if it was interrupted by a
|
|
* signal and 0 if @condition evaluated to true.
|
|
*/
|
|
#define wait_event_interruptible_exclusive_locked(wq, condition) \
|
|
((condition) \
|
|
? 0 : __wait_event_interruptible_locked(wq, condition, 1, 0))
|
|
|
|
/**
|
|
* wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* It must be called with wq.lock being held. This spinlock is
|
|
* unlocked while sleeping but @condition testing is done while lock
|
|
* is held and when this macro exits the lock is held.
|
|
*
|
|
* The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
|
|
* functions which must match the way they are locked/unlocked outside
|
|
* of this macro.
|
|
*
|
|
* The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
|
|
* set thus when other process waits process on the list if this
|
|
* process is awaken further processes are not considered.
|
|
*
|
|
* wake_up_locked() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* The function will return -ERESTARTSYS if it was interrupted by a
|
|
* signal and 0 if @condition evaluated to true.
|
|
*/
|
|
#define wait_event_interruptible_exclusive_locked_irq(wq, condition) \
|
|
((condition) \
|
|
? 0 : __wait_event_interruptible_locked(wq, condition, 1, 1))
|
|
|
|
|
|
#define __wait_event_killable(wq, condition) \
|
|
___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
|
|
|
|
/**
|
|
* wait_event_killable - sleep until a condition gets true
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
*
|
|
* The process is put to sleep (TASK_KILLABLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* The function will return -ERESTARTSYS if it was interrupted by a
|
|
* signal and 0 if @condition evaluated to true.
|
|
*/
|
|
#define wait_event_killable(wq, condition) \
|
|
({ \
|
|
int __ret = 0; \
|
|
might_sleep(); \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_killable(wq, condition); \
|
|
__ret; \
|
|
})
|
|
|
|
|
|
#define __wait_event_lock_irq(wq, condition, lock, cmd) \
|
|
(void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
|
|
spin_unlock_irq(&lock); \
|
|
cmd; \
|
|
schedule(); \
|
|
spin_lock_irq(&lock))
|
|
|
|
/**
|
|
* wait_event_lock_irq_cmd - sleep until a condition gets true. The
|
|
* condition is checked under the lock. This
|
|
* is expected to be called with the lock
|
|
* taken.
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @lock: a locked spinlock_t, which will be released before cmd
|
|
* and schedule() and reacquired afterwards.
|
|
* @cmd: a command which is invoked outside the critical section before
|
|
* sleep
|
|
*
|
|
* The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
|
|
* @condition evaluates to true. The @condition is checked each time
|
|
* the waitqueue @wq is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* This is supposed to be called while holding the lock. The lock is
|
|
* dropped before invoking the cmd and going to sleep and is reacquired
|
|
* afterwards.
|
|
*/
|
|
#define wait_event_lock_irq_cmd(wq, condition, lock, cmd) \
|
|
do { \
|
|
if (condition) \
|
|
break; \
|
|
__wait_event_lock_irq(wq, condition, lock, cmd); \
|
|
} while (0)
|
|
|
|
/**
|
|
* wait_event_lock_irq - sleep until a condition gets true. The
|
|
* condition is checked under the lock. This
|
|
* is expected to be called with the lock
|
|
* taken.
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @lock: a locked spinlock_t, which will be released before schedule()
|
|
* and reacquired afterwards.
|
|
*
|
|
* The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
|
|
* @condition evaluates to true. The @condition is checked each time
|
|
* the waitqueue @wq is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* This is supposed to be called while holding the lock. The lock is
|
|
* dropped before going to sleep and is reacquired afterwards.
|
|
*/
|
|
#define wait_event_lock_irq(wq, condition, lock) \
|
|
do { \
|
|
if (condition) \
|
|
break; \
|
|
__wait_event_lock_irq(wq, condition, lock, ); \
|
|
} while (0)
|
|
|
|
|
|
#define __wait_event_interruptible_lock_irq(wq, condition, lock, cmd) \
|
|
___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \
|
|
spin_unlock_irq(&lock); \
|
|
cmd; \
|
|
schedule(); \
|
|
spin_lock_irq(&lock))
|
|
|
|
/**
|
|
* wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
|
|
* The condition is checked under the lock. This is expected to
|
|
* be called with the lock taken.
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @lock: a locked spinlock_t, which will be released before cmd and
|
|
* schedule() and reacquired afterwards.
|
|
* @cmd: a command which is invoked outside the critical section before
|
|
* sleep
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received. The @condition is
|
|
* checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* This is supposed to be called while holding the lock. The lock is
|
|
* dropped before invoking the cmd and going to sleep and is reacquired
|
|
* afterwards.
|
|
*
|
|
* The macro will return -ERESTARTSYS if it was interrupted by a signal
|
|
* and 0 if @condition evaluated to true.
|
|
*/
|
|
#define wait_event_interruptible_lock_irq_cmd(wq, condition, lock, cmd) \
|
|
({ \
|
|
int __ret = 0; \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_interruptible_lock_irq(wq, \
|
|
condition, lock, cmd); \
|
|
__ret; \
|
|
})
|
|
|
|
/**
|
|
* wait_event_interruptible_lock_irq - sleep until a condition gets true.
|
|
* The condition is checked under the lock. This is expected
|
|
* to be called with the lock taken.
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @lock: a locked spinlock_t, which will be released before schedule()
|
|
* and reacquired afterwards.
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or signal is received. The @condition is
|
|
* checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* This is supposed to be called while holding the lock. The lock is
|
|
* dropped before going to sleep and is reacquired afterwards.
|
|
*
|
|
* The macro will return -ERESTARTSYS if it was interrupted by a signal
|
|
* and 0 if @condition evaluated to true.
|
|
*/
|
|
#define wait_event_interruptible_lock_irq(wq, condition, lock) \
|
|
({ \
|
|
int __ret = 0; \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_interruptible_lock_irq(wq, \
|
|
condition, lock,); \
|
|
__ret; \
|
|
})
|
|
|
|
#define __wait_event_interruptible_lock_irq_timeout(wq, condition, \
|
|
lock, timeout) \
|
|
___wait_event(wq, ___wait_cond_timeout(condition), \
|
|
TASK_INTERRUPTIBLE, 0, timeout, \
|
|
spin_unlock_irq(&lock); \
|
|
__ret = schedule_timeout(__ret); \
|
|
spin_lock_irq(&lock));
|
|
|
|
/**
|
|
* wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
|
|
* true or a timeout elapses. The condition is checked under
|
|
* the lock. This is expected to be called with the lock taken.
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @lock: a locked spinlock_t, which will be released before schedule()
|
|
* and reacquired afterwards.
|
|
* @timeout: timeout, in jiffies
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or signal is received. The @condition is
|
|
* checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* This is supposed to be called while holding the lock. The lock is
|
|
* dropped before going to sleep and is reacquired afterwards.
|
|
*
|
|
* The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
|
|
* was interrupted by a signal, and the remaining jiffies otherwise
|
|
* if the condition evaluated to true before the timeout elapsed.
|
|
*/
|
|
#define wait_event_interruptible_lock_irq_timeout(wq, condition, lock, \
|
|
timeout) \
|
|
({ \
|
|
long __ret = timeout; \
|
|
if (!___wait_cond_timeout(condition)) \
|
|
__ret = __wait_event_interruptible_lock_irq_timeout( \
|
|
wq, condition, lock, timeout); \
|
|
__ret; \
|
|
})
|
|
|
|
/*
|
|
* Waitqueues which are removed from the waitqueue_head at wakeup time
|
|
*/
|
|
void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);
|
|
void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state);
|
|
long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state);
|
|
void finish_wait(wait_queue_head_t *q, wait_queue_t *wait);
|
|
void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, unsigned int mode, void *key);
|
|
long wait_woken(wait_queue_t *wait, unsigned mode, long timeout);
|
|
int woken_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
|
|
int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
|
|
int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
|
|
|
|
#define DEFINE_WAIT_FUNC(name, function) \
|
|
wait_queue_t name = { \
|
|
.private = current, \
|
|
.func = function, \
|
|
.task_list = LIST_HEAD_INIT((name).task_list), \
|
|
}
|
|
|
|
#define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
|
|
|
|
#define DEFINE_WAIT_BIT(name, word, bit) \
|
|
struct wait_bit_queue name = { \
|
|
.key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \
|
|
.wait = { \
|
|
.private = current, \
|
|
.func = wake_bit_function, \
|
|
.task_list = \
|
|
LIST_HEAD_INIT((name).wait.task_list), \
|
|
}, \
|
|
}
|
|
|
|
#define init_wait(wait) \
|
|
do { \
|
|
(wait)->private = current; \
|
|
(wait)->func = autoremove_wake_function; \
|
|
INIT_LIST_HEAD(&(wait)->task_list); \
|
|
(wait)->flags = 0; \
|
|
} while (0)
|
|
|
|
|
|
extern int bit_wait(struct wait_bit_key *, int);
|
|
extern int bit_wait_io(struct wait_bit_key *, int);
|
|
extern int bit_wait_timeout(struct wait_bit_key *, int);
|
|
extern int bit_wait_io_timeout(struct wait_bit_key *, int);
|
|
|
|
/**
|
|
* wait_on_bit - wait for a bit to be cleared
|
|
* @word: the word being waited on, a kernel virtual address
|
|
* @bit: the bit of the word being waited on
|
|
* @mode: the task state to sleep in
|
|
*
|
|
* There is a standard hashed waitqueue table for generic use. This
|
|
* is the part of the hashtable's accessor API that waits on a bit.
|
|
* For instance, if one were to have waiters on a bitflag, one would
|
|
* call wait_on_bit() in threads waiting for the bit to clear.
|
|
* One uses wait_on_bit() where one is waiting for the bit to clear,
|
|
* but has no intention of setting it.
|
|
* Returned value will be zero if the bit was cleared, or non-zero
|
|
* if the process received a signal and the mode permitted wakeup
|
|
* on that signal.
|
|
*/
|
|
static inline int
|
|
wait_on_bit(unsigned long *word, int bit, unsigned mode)
|
|
{
|
|
might_sleep();
|
|
if (!test_bit(bit, word))
|
|
return 0;
|
|
return out_of_line_wait_on_bit(word, bit,
|
|
bit_wait,
|
|
mode);
|
|
}
|
|
|
|
/**
|
|
* wait_on_bit_io - wait for a bit to be cleared
|
|
* @word: the word being waited on, a kernel virtual address
|
|
* @bit: the bit of the word being waited on
|
|
* @mode: the task state to sleep in
|
|
*
|
|
* Use the standard hashed waitqueue table to wait for a bit
|
|
* to be cleared. This is similar to wait_on_bit(), but calls
|
|
* io_schedule() instead of schedule() for the actual waiting.
|
|
*
|
|
* Returned value will be zero if the bit was cleared, or non-zero
|
|
* if the process received a signal and the mode permitted wakeup
|
|
* on that signal.
|
|
*/
|
|
static inline int
|
|
wait_on_bit_io(unsigned long *word, int bit, unsigned mode)
|
|
{
|
|
might_sleep();
|
|
if (!test_bit(bit, word))
|
|
return 0;
|
|
return out_of_line_wait_on_bit(word, bit,
|
|
bit_wait_io,
|
|
mode);
|
|
}
|
|
|
|
/**
|
|
* wait_on_bit_timeout - wait for a bit to be cleared or a timeout elapses
|
|
* @word: the word being waited on, a kernel virtual address
|
|
* @bit: the bit of the word being waited on
|
|
* @mode: the task state to sleep in
|
|
* @timeout: timeout, in jiffies
|
|
*
|
|
* Use the standard hashed waitqueue table to wait for a bit
|
|
* to be cleared. This is similar to wait_on_bit(), except also takes a
|
|
* timeout parameter.
|
|
*
|
|
* Returned value will be zero if the bit was cleared before the
|
|
* @timeout elapsed, or non-zero if the @timeout elapsed or process
|
|
* received a signal and the mode permitted wakeup on that signal.
|
|
*/
|
|
static inline int
|
|
wait_on_bit_timeout(unsigned long *word, int bit, unsigned mode,
|
|
unsigned long timeout)
|
|
{
|
|
might_sleep();
|
|
if (!test_bit(bit, word))
|
|
return 0;
|
|
return out_of_line_wait_on_bit_timeout(word, bit,
|
|
bit_wait_timeout,
|
|
mode, timeout);
|
|
}
|
|
|
|
/**
|
|
* wait_on_bit_action - wait for a bit to be cleared
|
|
* @word: the word being waited on, a kernel virtual address
|
|
* @bit: the bit of the word being waited on
|
|
* @action: the function used to sleep, which may take special actions
|
|
* @mode: the task state to sleep in
|
|
*
|
|
* Use the standard hashed waitqueue table to wait for a bit
|
|
* to be cleared, and allow the waiting action to be specified.
|
|
* This is like wait_on_bit() but allows fine control of how the waiting
|
|
* is done.
|
|
*
|
|
* Returned value will be zero if the bit was cleared, or non-zero
|
|
* if the process received a signal and the mode permitted wakeup
|
|
* on that signal.
|
|
*/
|
|
static inline int
|
|
wait_on_bit_action(unsigned long *word, int bit, wait_bit_action_f *action,
|
|
unsigned mode)
|
|
{
|
|
might_sleep();
|
|
if (!test_bit(bit, word))
|
|
return 0;
|
|
return out_of_line_wait_on_bit(word, bit, action, mode);
|
|
}
|
|
|
|
/**
|
|
* wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
|
|
* @word: the word being waited on, a kernel virtual address
|
|
* @bit: the bit of the word being waited on
|
|
* @mode: the task state to sleep in
|
|
*
|
|
* There is a standard hashed waitqueue table for generic use. This
|
|
* is the part of the hashtable's accessor API that waits on a bit
|
|
* when one intends to set it, for instance, trying to lock bitflags.
|
|
* For instance, if one were to have waiters trying to set bitflag
|
|
* and waiting for it to clear before setting it, one would call
|
|
* wait_on_bit() in threads waiting to be able to set the bit.
|
|
* One uses wait_on_bit_lock() where one is waiting for the bit to
|
|
* clear with the intention of setting it, and when done, clearing it.
|
|
*
|
|
* Returns zero if the bit was (eventually) found to be clear and was
|
|
* set. Returns non-zero if a signal was delivered to the process and
|
|
* the @mode allows that signal to wake the process.
|
|
*/
|
|
static inline int
|
|
wait_on_bit_lock(unsigned long *word, int bit, unsigned mode)
|
|
{
|
|
might_sleep();
|
|
if (!test_and_set_bit(bit, word))
|
|
return 0;
|
|
return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode);
|
|
}
|
|
|
|
/**
|
|
* wait_on_bit_lock_io - wait for a bit to be cleared, when wanting to set it
|
|
* @word: the word being waited on, a kernel virtual address
|
|
* @bit: the bit of the word being waited on
|
|
* @mode: the task state to sleep in
|
|
*
|
|
* Use the standard hashed waitqueue table to wait for a bit
|
|
* to be cleared and then to atomically set it. This is similar
|
|
* to wait_on_bit(), but calls io_schedule() instead of schedule()
|
|
* for the actual waiting.
|
|
*
|
|
* Returns zero if the bit was (eventually) found to be clear and was
|
|
* set. Returns non-zero if a signal was delivered to the process and
|
|
* the @mode allows that signal to wake the process.
|
|
*/
|
|
static inline int
|
|
wait_on_bit_lock_io(unsigned long *word, int bit, unsigned mode)
|
|
{
|
|
might_sleep();
|
|
if (!test_and_set_bit(bit, word))
|
|
return 0;
|
|
return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode);
|
|
}
|
|
|
|
/**
|
|
* wait_on_bit_lock_action - wait for a bit to be cleared, when wanting to set it
|
|
* @word: the word being waited on, a kernel virtual address
|
|
* @bit: the bit of the word being waited on
|
|
* @action: the function used to sleep, which may take special actions
|
|
* @mode: the task state to sleep in
|
|
*
|
|
* Use the standard hashed waitqueue table to wait for a bit
|
|
* to be cleared and then to set it, and allow the waiting action
|
|
* to be specified.
|
|
* This is like wait_on_bit() but allows fine control of how the waiting
|
|
* is done.
|
|
*
|
|
* Returns zero if the bit was (eventually) found to be clear and was
|
|
* set. Returns non-zero if a signal was delivered to the process and
|
|
* the @mode allows that signal to wake the process.
|
|
*/
|
|
static inline int
|
|
wait_on_bit_lock_action(unsigned long *word, int bit, wait_bit_action_f *action,
|
|
unsigned mode)
|
|
{
|
|
might_sleep();
|
|
if (!test_and_set_bit(bit, word))
|
|
return 0;
|
|
return out_of_line_wait_on_bit_lock(word, bit, action, mode);
|
|
}
|
|
|
|
/**
|
|
* wait_on_atomic_t - Wait for an atomic_t to become 0
|
|
* @val: The atomic value being waited on, a kernel virtual address
|
|
* @action: the function used to sleep, which may take special actions
|
|
* @mode: the task state to sleep in
|
|
*
|
|
* Wait for an atomic_t to become 0. We abuse the bit-wait waitqueue table for
|
|
* the purpose of getting a waitqueue, but we set the key to a bit number
|
|
* outside of the target 'word'.
|
|
*/
|
|
static inline
|
|
int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
|
|
{
|
|
might_sleep();
|
|
if (atomic_read(val) == 0)
|
|
return 0;
|
|
return out_of_line_wait_on_atomic_t(val, action, mode);
|
|
}
|
|
|
|
#endif /* _LINUX_WAIT_H */
|