diff options
Diffstat (limited to 'kernel/include/linux/wait.h')
| -rw-r--r-- | kernel/include/linux/wait.h | 1156 |
1 files changed, 1156 insertions, 0 deletions
diff --git a/kernel/include/linux/wait.h b/kernel/include/linux/wait.h new file mode 100644 index 000000000..b3b54c26b --- /dev/null +++ b/kernel/include/linux/wait.h @@ -0,0 +1,1156 @@ +#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> +#include <linux/atomic.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; +} + +static inline int waitqueue_active(wait_queue_head_t *q) +{ + return !list_empty(&q->task_list); +} + +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 *); +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 - 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_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 *); +extern int bit_wait_io(struct wait_bit_key *); +extern int bit_wait_timeout(struct wait_bit_key *); +extern int bit_wait_io_timeout(struct wait_bit_key *); + +/** + * 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(void *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(void *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(void *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(void *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(void *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(void *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(void *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 */ |