cregit-Linux how code gets into the kernel

Release 4.7 include/linux/wait.h

Directory: include/linux
#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; }

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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; }

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/** * 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); }

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/** * 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); }

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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); }

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/* * 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); }

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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); }

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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); }

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static inline void __remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old) { list_del(&old->task_list); }

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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); }

Contributors

PersonTokensPropCommitsCommitProp
neil brownneil brown3065.22%125.00%
william lee irwin iiiwilliam lee irwin iii1123.91%125.00%
peter zijlstrapeter zijlstra36.52%125.00%
palmer dabbeltpalmer dabbelt24.35%125.00%
Total46100.00%4100.00%

/** * 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); }

Contributors

PersonTokensPropCommitsCommitProp
neil brownneil brown4189.13%133.33%
peter zijlstrapeter zijlstra36.52%133.33%
palmer dabbeltpalmer dabbelt24.35%133.33%
Total46100.00%3100.00%

/** * 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); }

Contributors

PersonTokensPropCommitsCommitProp
johan hedbergjohan hedberg5096.15%150.00%
palmer dabbeltpalmer dabbelt23.85%150.00%
Total52100.00%2100.00%

/** * 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); }

Contributors

PersonTokensPropCommitsCommitProp
william lee irwin iiiwilliam lee irwin iii3366.00%233.33%
neil brownneil brown1224.00%233.33%
peter zijlstrapeter zijlstra36.00%116.67%
palmer dabbeltpalmer dabbelt24.00%116.67%
Total50100.00%6100.00%

/** * 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); }

Contributors

PersonTokensPropCommitsCommitProp
neil brownneil brown3065.22%125.00%
william lee irwin iiiwilliam lee irwin iii1123.91%125.00%
peter zijlstrapeter zijlstra36.52%125.00%
palmer dabbeltpalmer dabbelt24.35%125.00%
Total46100.00%4100.00%

/** * 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); }

Contributors

PersonTokensPropCommitsCommitProp
neil brownneil brown4189.13%133.33%
peter zijlstrapeter zijlstra36.52%133.33%
palmer dabbeltpalmer dabbelt24.35%133.33%
Total46100.00%3100.00%

/** * 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); }

Contributors

PersonTokensPropCommitsCommitProp
william lee irwin iiiwilliam lee irwin iii3366.00%233.33%
neil brownneil brown1224.00%233.33%
peter zijlstrapeter zijlstra36.00%116.67%
palmer dabbeltpalmer dabbelt24.00%116.67%
Total50100.00%6100.00%

/** * 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); }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells4693.88%150.00%
peter zijlstrapeter zijlstra36.12%150.00%
Total49100.00%2100.00%

#endif /* _LINUX_WAIT_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
peter zijlstrapeter zijlstra27913.75%1620.25%
neil brownneil brown24211.93%33.80%
pre-gitpre-git21310.50%1012.66%
william lee irwin iiiwilliam lee irwin iii1869.17%45.06%
matthew wilcoxmatthew wilcox1607.89%33.80%
harvey harrisonharvey harrison1437.05%11.27%
david howellsdavid howells874.29%22.53%
benjamin lahaisebenjamin lahaise813.99%22.53%
lukas czernerlukas czerner793.89%11.27%
davide libenzidavide libenzi623.06%22.53%
michal nazarewiczmichal nazarewicz582.86%11.27%
changli gaochangli gao562.76%11.27%
andrew mortonandrew morton522.56%33.80%
johan hedbergjohan hedberg512.51%11.27%
kent overstreetkent overstreet371.82%11.27%
yuanhan liuyuanhan liu291.43%11.27%
shaohua lishaohua li271.33%11.27%
martin peschkemartin peschke241.18%11.27%
herbert xuherbert xu221.08%11.27%
russell kingrussell king211.03%11.27%
johannes weinerjohannes weiner200.99%11.27%
dean nelsondean nelson180.89%11.27%
oleg nesterovoleg nesterov170.84%22.53%
palmer dabbeltpalmer dabbelt140.69%11.27%
thomas gleixnerthomas gleixner110.54%11.27%
eric dumazeteric dumazet110.54%11.27%
ingo molnaringo molnar100.49%45.06%
linus torvaldslinus torvalds40.20%11.27%
tim schmielautim schmielau30.15%11.27%
scot doylescot doyle20.10%11.27%
martin waitzmartin waitz20.10%11.27%
evgeny kuznetsovevgeny kuznetsov10.05%11.27%
robert loverobert love10.05%11.27%
andrea arcangeliandrea arcangeli10.05%11.27%
heiko carstensheiko carstens10.05%11.27%
masanari iidamasanari iida10.05%11.27%
thierry redingthierry reding10.05%11.27%
mikulas patockamikulas patocka10.05%11.27%
stafford hornestafford horne10.05%11.27%
Total2029100.00%79100.00%
Directory: include/linux
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