diff options
Diffstat (limited to 'include/linux/wait.h')
| -rw-r--r-- | include/linux/wait.h | 460 |
1 files changed, 460 insertions, 0 deletions
diff --git a/include/linux/wait.h b/include/linux/wait.h new file mode 100644 index 00000000000..17c874a8eb3 --- /dev/null +++ b/include/linux/wait.h @@ -0,0 +1,460 @@ +#ifndef _LINUX_WAIT_H +#define _LINUX_WAIT_H + +#define WNOHANG 0x00000001 +#define WUNTRACED 0x00000002 +#define WSTOPPED WUNTRACED +#define WEXITED 0x00000004 +#define WCONTINUED 0x00000008 +#define WNOWAIT 0x01000000 /* Don't reap, just poll status. */ + +#define __WNOTHREAD 0x20000000 /* Don't wait on children of other threads in this group */ +#define __WALL 0x40000000 /* Wait on all children, regardless of type */ +#define __WCLONE 0x80000000 /* Wait only on non-SIGCHLD children */ + +/* First argument to waitid: */ +#define P_ALL 0 +#define P_PID 1 +#define P_PGID 2 + +#ifdef __KERNEL__ + +#include <linux/config.h> +#include <linux/list.h> +#include <linux/stddef.h> +#include <linux/spinlock.h> +#include <asm/system.h> +#include <asm/current.h> + +typedef struct __wait_queue wait_queue_t; +typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int sync, void *key); +int default_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key); + +struct __wait_queue { + unsigned int flags; +#define WQ_FLAG_EXCLUSIVE 0x01 + struct task_struct * task; + wait_queue_func_t func; + struct list_head task_list; +}; + +struct wait_bit_key { + void *flags; + int bit_nr; +}; + +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; + + +/* + * Macros for declaration and initialisaton of the datatypes + */ + +#define __WAITQUEUE_INITIALIZER(name, tsk) { \ + .task = 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, \ + .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, } + +static inline void init_waitqueue_head(wait_queue_head_t *q) +{ + spin_lock_init(&q->lock); + INIT_LIST_HEAD(&q->task_list); +} + +static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p) +{ + q->flags = 0; + q->task = 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->task = NULL; + q->func = func; +} + +static inline int waitqueue_active(wait_queue_head_t *q) +{ + return !list_empty(&q->task_list); +} + +/* + * Used to distinguish between sync and async io wait context: + * sync i/o typically specifies a NULL wait queue entry or a wait + * queue entry bound to a task (current task) to wake up. + * aio specifies a wait queue entry with an async notification + * callback routine, not associated with any task. + */ +#define is_sync_wait(wait) (!(wait) || ((wait)->task)) + +extern void FASTCALL(add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait)); +extern void FASTCALL(add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t * wait)); +extern void FASTCALL(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_tail(wait_queue_head_t *head, + wait_queue_t *new) +{ + list_add_tail(&new->task_list, &head->task_list); +} + +static inline void __remove_wait_queue(wait_queue_head_t *head, + wait_queue_t *old) +{ + list_del(&old->task_list); +} + +void FASTCALL(__wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key)); +extern void FASTCALL(__wake_up_locked(wait_queue_head_t *q, unsigned int mode)); +extern void FASTCALL(__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr)); +void FASTCALL(__wake_up_bit(wait_queue_head_t *, void *, int)); +int FASTCALL(__wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned)); +int FASTCALL(__wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned)); +void FASTCALL(wake_up_bit(void *, int)); +int FASTCALL(out_of_line_wait_on_bit(void *, int, int (*)(void *), unsigned)); +int FASTCALL(out_of_line_wait_on_bit_lock(void *, int, int (*)(void *), unsigned)); +wait_queue_head_t *FASTCALL(bit_waitqueue(void *, int)); + +#define wake_up(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1, NULL) +#define wake_up_nr(x, nr) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr, NULL) +#define wake_up_all(x) __wake_up(x, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 0, NULL) +#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_locked(x) __wake_up_locked((x), TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE) +#define wake_up_interruptible_sync(x) __wake_up_sync((x),TASK_INTERRUPTIBLE, 1) + +#define __wait_event(wq, condition) \ +do { \ + DEFINE_WAIT(__wait); \ + \ + for (;;) { \ + prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \ + if (condition) \ + break; \ + schedule(); \ + } \ + finish_wait(&wq, &__wait); \ +} while (0) + +/** + * 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 { \ + if (condition) \ + break; \ + __wait_event(wq, condition); \ +} while (0) + +#define __wait_event_timeout(wq, condition, ret) \ +do { \ + DEFINE_WAIT(__wait); \ + \ + for (;;) { \ + prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \ + if (condition) \ + break; \ + ret = schedule_timeout(ret); \ + if (!ret) \ + break; \ + } \ + finish_wait(&wq, &__wait); \ +} while (0) + +/** + * 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. + * + * The function returns 0 if the @timeout elapsed, and the remaining + * jiffies if the condition evaluated to true before the timeout elapsed. + */ +#define wait_event_timeout(wq, condition, timeout) \ +({ \ + long __ret = timeout; \ + if (!(condition)) \ + __wait_event_timeout(wq, condition, __ret); \ + __ret; \ +}) + +#define __wait_event_interruptible(wq, condition, ret) \ +do { \ + DEFINE_WAIT(__wait); \ + \ + for (;;) { \ + prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \ + if (condition) \ + break; \ + if (!signal_pending(current)) { \ + schedule(); \ + continue; \ + } \ + ret = -ERESTARTSYS; \ + break; \ + } \ + finish_wait(&wq, &__wait); \ +} while (0) + +/** + * 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; \ + if (!(condition)) \ + __wait_event_interruptible(wq, condition, __ret); \ + __ret; \ +}) + +#define __wait_event_interruptible_timeout(wq, condition, ret) \ +do { \ + DEFINE_WAIT(__wait); \ + \ + for (;;) { \ + prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \ + if (condition) \ + break; \ + if (!signal_pending(current)) { \ + ret = schedule_timeout(ret); \ + if (!ret) \ + break; \ + continue; \ + } \ + ret = -ERESTARTSYS; \ + break; \ + } \ + finish_wait(&wq, &__wait); \ +} while (0) + +/** + * 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. + * + * 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_timeout(wq, condition, timeout) \ +({ \ + long __ret = timeout; \ + if (!(condition)) \ + __wait_event_interruptible_timeout(wq, condition, __ret); \ + __ret; \ +}) + +#define __wait_event_interruptible_exclusive(wq, condition, ret) \ +do { \ + DEFINE_WAIT(__wait); \ + \ + for (;;) { \ + prepare_to_wait_exclusive(&wq, &__wait, \ + TASK_INTERRUPTIBLE); \ + if (condition) \ + break; \ + if (!signal_pending(current)) { \ + schedule(); \ + continue; \ + } \ + ret = -ERESTARTSYS; \ + break; \ + } \ + finish_wait(&wq, &__wait); \ +} while (0) + +#define wait_event_interruptible_exclusive(wq, condition) \ +({ \ + int __ret = 0; \ + if (!(condition)) \ + __wait_event_interruptible_exclusive(wq, condition, __ret);\ + __ret; \ +}) + +/* + * Must be called with the spinlock in the wait_queue_head_t held. + */ +static inline void add_wait_queue_exclusive_locked(wait_queue_head_t *q, + wait_queue_t * wait) +{ + wait->flags |= WQ_FLAG_EXCLUSIVE; + __add_wait_queue_tail(q, wait); +} + +/* + * Must be called with the spinlock in the wait_queue_head_t held. + */ +static inline void remove_wait_queue_locked(wait_queue_head_t *q, + wait_queue_t * wait) +{ + __remove_wait_queue(q, wait); +} + +/* + * These are the old interfaces to sleep waiting for an event. + * They are racy. DO NOT use them, use the wait_event* interfaces above. + * We plan to remove these interfaces during 2.7. + */ +extern void FASTCALL(sleep_on(wait_queue_head_t *q)); +extern long FASTCALL(sleep_on_timeout(wait_queue_head_t *q, + signed long timeout)); +extern void FASTCALL(interruptible_sleep_on(wait_queue_head_t *q)); +extern long FASTCALL(interruptible_sleep_on_timeout(wait_queue_head_t *q, + signed long timeout)); + +/* + * Waitqueues which are removed from the waitqueue_head at wakeup time + */ +void FASTCALL(prepare_to_wait(wait_queue_head_t *q, + wait_queue_t *wait, int state)); +void FASTCALL(prepare_to_wait_exclusive(wait_queue_head_t *q, + wait_queue_t *wait, int state)); +void FASTCALL(finish_wait(wait_queue_head_t *q, wait_queue_t *wait)); +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(name) \ + wait_queue_t name = { \ + .task = current, \ + .func = autoremove_wake_function, \ + .task_list = { .next = &(name).task_list, \ + .prev = &(name).task_list, \ + }, \ + } + +#define DEFINE_WAIT_BIT(name, word, bit) \ + struct wait_bit_queue name = { \ + .key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \ + .wait = { \ + .task = current, \ + .func = wake_bit_function, \ + .task_list = \ + LIST_HEAD_INIT((name).wait.task_list), \ + }, \ + } + +#define init_wait(wait) \ + do { \ + (wait)->task = current; \ + (wait)->func = autoremove_wake_function; \ + INIT_LIST_HEAD(&(wait)->task_list); \ + } while (0) + +/** + * 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 + * @action: the function used to sleep, which may take special actions + * @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. + */ +static inline int wait_on_bit(void *word, int bit, + int (*action)(void *), unsigned mode) +{ + 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 + * @action: the function used to sleep, which may take special actions + * @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. + */ +static inline int wait_on_bit_lock(void *word, int bit, + int (*action)(void *), unsigned mode) +{ + if (!test_and_set_bit(bit, word)) + return 0; + return out_of_line_wait_on_bit_lock(word, bit, action, mode); +} + +#endif /* __KERNEL__ */ + +#endif |