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Diffstat (limited to 'include/linux/wait.h')
| -rw-r--r-- | include/linux/wait.h | 1221 |
1 files changed, 1221 insertions, 0 deletions
diff --git a/include/linux/wait.h b/include/linux/wait.h new file mode 100644 index 000000000..a0307b516 --- /dev/null +++ b/include/linux/wait.h @@ -0,0 +1,1221 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#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_entry wait_queue_entry_t; + +typedef int (*wait_queue_func_t)(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key); +int default_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key); + +/* wait_queue_entry::flags */ +#define WQ_FLAG_EXCLUSIVE 0x01 +#define WQ_FLAG_WOKEN 0x02 +#define WQ_FLAG_BOOKMARK 0x04 +#define WQ_FLAG_CUSTOM 0x08 +#define WQ_FLAG_DONE 0x10 +#define WQ_FLAG_PRIORITY 0x20 + +/* + * A single wait-queue entry structure: + */ +struct wait_queue_entry { + unsigned int flags; + void *private; + wait_queue_func_t func; + struct list_head entry; +}; + +struct wait_queue_head { + spinlock_t lock; + struct list_head head; +}; +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, \ + .entry = { NULL, NULL } } + +#define DECLARE_WAITQUEUE(name, tsk) \ + struct wait_queue_entry name = __WAITQUEUE_INITIALIZER(name, tsk) + +#define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \ + .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ + .head = LIST_HEAD_INIT(name.head) } + +#define DECLARE_WAIT_QUEUE_HEAD(name) \ + struct wait_queue_head name = __WAIT_QUEUE_HEAD_INITIALIZER(name) + +extern void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *); + +#define init_waitqueue_head(wq_head) \ + do { \ + static struct lock_class_key __key; \ + \ + __init_waitqueue_head((wq_head), #wq_head, &__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) \ + struct wait_queue_head 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(struct wait_queue_entry *wq_entry, struct task_struct *p) +{ + wq_entry->flags = 0; + wq_entry->private = p; + wq_entry->func = default_wake_function; +} + +static inline void +init_waitqueue_func_entry(struct wait_queue_entry *wq_entry, wait_queue_func_t func) +{ + wq_entry->flags = 0; + wq_entry->private = NULL; + wq_entry->func = func; +} + +/** + * waitqueue_active -- locklessly test for waiters on the queue + * @wq_head: 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::lock or when used for wakeups + * with an extra smp_mb() like:: + * + * CPU0 - waker CPU1 - waiter + * + * for (;;) { + * @cond = true; prepare_to_wait(&wq_head, &wait, state); + * smp_mb(); // smp_mb() from set_current_state() + * if (waitqueue_active(wq_head)) if (@cond) + * wake_up(wq_head); break; + * schedule(); + * } + * finish_wait(&wq_head, &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(struct wait_queue_head *wq_head) +{ + return !list_empty(&wq_head->head); +} + +/** + * wq_has_single_sleeper - check if there is only one sleeper + * @wq_head: wait queue head + * + * Returns true of wq_head has only one sleeper on the list. + * + * Please refer to the comment for waitqueue_active. + */ +static inline bool wq_has_single_sleeper(struct wait_queue_head *wq_head) +{ + return list_is_singular(&wq_head->head); +} + +/** + * wq_has_sleeper - check if there are any waiting processes + * @wq_head: wait queue head + * + * Returns true if wq_head has waiting processes + * + * Please refer to the comment for waitqueue_active. + */ +static inline bool wq_has_sleeper(struct wait_queue_head *wq_head) +{ + /* + * 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_head); +} + +extern void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry); +extern void add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry); +extern void add_wait_queue_priority(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry); +extern void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry); + +static inline void __add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) +{ + struct list_head *head = &wq_head->head; + struct wait_queue_entry *wq; + + list_for_each_entry(wq, &wq_head->head, entry) { + if (!(wq->flags & WQ_FLAG_PRIORITY)) + break; + head = &wq->entry; + } + list_add(&wq_entry->entry, head); +} + +/* + * Used for wake-one threads: + */ +static inline void +__add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) +{ + wq_entry->flags |= WQ_FLAG_EXCLUSIVE; + __add_wait_queue(wq_head, wq_entry); +} + +static inline void __add_wait_queue_entry_tail(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) +{ + list_add_tail(&wq_entry->entry, &wq_head->head); +} + +static inline void +__add_wait_queue_entry_tail_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) +{ + wq_entry->flags |= WQ_FLAG_EXCLUSIVE; + __add_wait_queue_entry_tail(wq_head, wq_entry); +} + +static inline void +__remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) +{ + list_del(&wq_entry->entry); +} + +int __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key); +void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key); +void __wake_up_locked_key_bookmark(struct wait_queue_head *wq_head, + unsigned int mode, void *key, wait_queue_entry_t *bookmark); +void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, void *key); +void __wake_up_locked_sync_key(struct wait_queue_head *wq_head, unsigned int mode, void *key); +void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr); +void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode); +void __wake_up_pollfree(struct wait_queue_head *wq_head); + +#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) + +/* + * Wakeup macros to be used to report events to the targets. + */ +#define poll_to_key(m) ((void *)(__force uintptr_t)(__poll_t)(m)) +#define key_to_poll(m) ((__force __poll_t)(uintptr_t)(void *)(m)) +#define wake_up_poll(x, m) \ + __wake_up(x, TASK_NORMAL, 1, poll_to_key(m)) +#define wake_up_locked_poll(x, m) \ + __wake_up_locked_key((x), TASK_NORMAL, poll_to_key(m)) +#define wake_up_interruptible_poll(x, m) \ + __wake_up(x, TASK_INTERRUPTIBLE, 1, poll_to_key(m)) +#define wake_up_interruptible_sync_poll(x, m) \ + __wake_up_sync_key((x), TASK_INTERRUPTIBLE, poll_to_key(m)) +#define wake_up_interruptible_sync_poll_locked(x, m) \ + __wake_up_locked_sync_key((x), TASK_INTERRUPTIBLE, poll_to_key(m)) + +/** + * wake_up_pollfree - signal that a polled waitqueue is going away + * @wq_head: the wait queue head + * + * In the very rare cases where a ->poll() implementation uses a waitqueue whose + * lifetime is tied to a task rather than to the 'struct file' being polled, + * this function must be called before the waitqueue is freed so that + * non-blocking polls (e.g. epoll) are notified that the queue is going away. + * + * The caller must also RCU-delay the freeing of the wait_queue_head, e.g. via + * an explicit synchronize_rcu() or call_rcu(), or via SLAB_TYPESAFE_BY_RCU. + */ +static inline void wake_up_pollfree(struct wait_queue_head *wq_head) +{ + /* + * For performance reasons, we don't always take the queue lock here. + * Therefore, we might race with someone removing the last entry from + * the queue, and proceed while they still hold the queue lock. + * However, rcu_read_lock() is required to be held in such cases, so we + * can safely proceed with an RCU-delayed free. + */ + if (waitqueue_active(wq_head)) + __wake_up_pollfree(wq_head); +} + +#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 | TASK_WAKEKILL))) + +extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags); + +/* + * 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_head, condition, state, exclusive, ret, cmd) \ +({ \ + __label__ __out; \ + struct wait_queue_entry __wq_entry; \ + long __ret = ret; /* explicit shadow */ \ + \ + init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0); \ + for (;;) { \ + long __int = prepare_to_wait_event(&wq_head, &__wq_entry, state);\ + \ + if (condition) \ + break; \ + \ + if (___wait_is_interruptible(state) && __int) { \ + __ret = __int; \ + goto __out; \ + } \ + \ + cmd; \ + } \ + finish_wait(&wq_head, &__wq_entry); \ +__out: __ret; \ +}) + +#define __wait_event(wq_head, condition) \ + (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \ + schedule()) + +/** + * wait_event - sleep until a condition gets true + * @wq_head: 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_head 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_head, condition) \ +do { \ + might_sleep(); \ + if (condition) \ + break; \ + __wait_event(wq_head, condition); \ +} while (0) + +#define __io_wait_event(wq_head, condition) \ + (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \ + io_schedule()) + +/* + * io_wait_event() -- like wait_event() but with io_schedule() + */ +#define io_wait_event(wq_head, condition) \ +do { \ + might_sleep(); \ + if (condition) \ + break; \ + __io_wait_event(wq_head, condition); \ +} while (0) + +#define __wait_event_freezable(wq_head, condition) \ + ___wait_event(wq_head, condition, (TASK_INTERRUPTIBLE|TASK_FREEZABLE), \ + 0, 0, schedule()) + +/** + * wait_event_freezable - sleep (or freeze) until a condition gets true + * @wq_head: 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_head 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_head, condition) \ +({ \ + int __ret = 0; \ + might_sleep(); \ + if (!(condition)) \ + __ret = __wait_event_freezable(wq_head, condition); \ + __ret; \ +}) + +#define __wait_event_timeout(wq_head, condition, timeout) \ + ___wait_event(wq_head, ___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_head: 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_head 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_head, condition, timeout) \ +({ \ + long __ret = timeout; \ + might_sleep(); \ + if (!___wait_cond_timeout(condition)) \ + __ret = __wait_event_timeout(wq_head, condition, timeout); \ + __ret; \ +}) + +#define __wait_event_freezable_timeout(wq_head, condition, timeout) \ + ___wait_event(wq_head, ___wait_cond_timeout(condition), \ + (TASK_INTERRUPTIBLE|TASK_FREEZABLE), 0, timeout, \ + __ret = schedule_timeout(__ret)) + +/* + * like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid + * increasing load and is freezable. + */ +#define wait_event_freezable_timeout(wq_head, condition, timeout) \ +({ \ + long __ret = timeout; \ + might_sleep(); \ + if (!___wait_cond_timeout(condition)) \ + __ret = __wait_event_freezable_timeout(wq_head, condition, timeout); \ + __ret; \ +}) + +#define __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2) \ + (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 1, 0, \ + cmd1; schedule(); cmd2) +/* + * Just like wait_event_cmd(), except it sets exclusive flag + */ +#define wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2) \ +do { \ + if (condition) \ + break; \ + __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2); \ +} while (0) + +#define __wait_event_cmd(wq_head, condition, cmd1, cmd2) \ + (void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \ + cmd1; schedule(); cmd2) + +/** + * wait_event_cmd - sleep until a condition gets true + * @wq_head: 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_head 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_head, condition, cmd1, cmd2) \ +do { \ + if (condition) \ + break; \ + __wait_event_cmd(wq_head, condition, cmd1, cmd2); \ +} while (0) + +#define __wait_event_interruptible(wq_head, condition) \ + ___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \ + schedule()) + +/** + * wait_event_interruptible - sleep until a condition gets true + * @wq_head: 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_head 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_head, condition) \ +({ \ + int __ret = 0; \ + might_sleep(); \ + if (!(condition)) \ + __ret = __wait_event_interruptible(wq_head, condition); \ + __ret; \ +}) + +#define __wait_event_interruptible_timeout(wq_head, condition, timeout) \ + ___wait_event(wq_head, ___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_head: 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_head 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_head, condition, timeout) \ +({ \ + long __ret = timeout; \ + might_sleep(); \ + if (!___wait_cond_timeout(condition)) \ + __ret = __wait_event_interruptible_timeout(wq_head, \ + condition, timeout); \ + __ret; \ +}) + +#define __wait_event_hrtimeout(wq_head, condition, timeout, state) \ +({ \ + int __ret = 0; \ + struct hrtimer_sleeper __t; \ + \ + hrtimer_init_sleeper_on_stack(&__t, CLOCK_MONOTONIC, \ + HRTIMER_MODE_REL); \ + if ((timeout) != KTIME_MAX) { \ + hrtimer_set_expires_range_ns(&__t.timer, timeout, \ + current->timer_slack_ns); \ + hrtimer_sleeper_start_expires(&__t, HRTIMER_MODE_REL); \ + } \ + \ + __ret = ___wait_event(wq_head, 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_head: 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_head 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_head, condition, timeout) \ +({ \ + int __ret = 0; \ + might_sleep(); \ + if (!(condition)) \ + __ret = __wait_event_hrtimeout(wq_head, 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_killable_exclusive(wq, condition) \ + ___wait_event(wq, condition, TASK_KILLABLE, 1, 0, \ + schedule()) + +#define wait_event_killable_exclusive(wq, condition) \ +({ \ + int __ret = 0; \ + might_sleep(); \ + if (!(condition)) \ + __ret = __wait_event_killable_exclusive(wq, condition); \ + __ret; \ +}) + + +#define __wait_event_freezable_exclusive(wq, condition) \ + ___wait_event(wq, condition, (TASK_INTERRUPTIBLE|TASK_FREEZABLE), 1, 0,\ + schedule()) + +#define wait_event_freezable_exclusive(wq, condition) \ +({ \ + int __ret = 0; \ + might_sleep(); \ + if (!(condition)) \ + __ret = __wait_event_freezable_exclusive(wq, condition); \ + __ret; \ +}) + +/** + * wait_event_idle - wait for a condition without contributing to system load + * @wq_head: the waitqueue to wait on + * @condition: a C expression for the event to wait for + * + * The process is put to sleep (TASK_IDLE) until the + * @condition evaluates to true. + * The @condition is checked each time the waitqueue @wq_head 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_idle(wq_head, condition) \ +do { \ + might_sleep(); \ + if (!(condition)) \ + ___wait_event(wq_head, condition, TASK_IDLE, 0, 0, schedule()); \ +} while (0) + +/** + * wait_event_idle_exclusive - wait for a condition with contributing to system load + * @wq_head: the waitqueue to wait on + * @condition: a C expression for the event to wait for + * + * The process is put to sleep (TASK_IDLE) until the + * @condition evaluates to true. + * The @condition is checked each time the waitqueue @wq_head is woken up. + * + * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag + * set thus if other processes wait on the same list, when this + * process is woken further processes are not considered. + * + * wake_up() has to be called after changing any variable that could + * change the result of the wait condition. + * + */ +#define wait_event_idle_exclusive(wq_head, condition) \ +do { \ + might_sleep(); \ + if (!(condition)) \ + ___wait_event(wq_head, condition, TASK_IDLE, 1, 0, schedule()); \ +} while (0) + +#define __wait_event_idle_timeout(wq_head, condition, timeout) \ + ___wait_event(wq_head, ___wait_cond_timeout(condition), \ + TASK_IDLE, 0, timeout, \ + __ret = schedule_timeout(__ret)) + +/** + * wait_event_idle_timeout - sleep without load until a condition becomes true or a timeout elapses + * @wq_head: 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_IDLE) until the + * @condition evaluates to true. The @condition is checked each time + * the waitqueue @wq_head 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_idle_timeout(wq_head, condition, timeout) \ +({ \ + long __ret = timeout; \ + might_sleep(); \ + if (!___wait_cond_timeout(condition)) \ + __ret = __wait_event_idle_timeout(wq_head, condition, timeout); \ + __ret; \ +}) + +#define __wait_event_idle_exclusive_timeout(wq_head, condition, timeout) \ + ___wait_event(wq_head, ___wait_cond_timeout(condition), \ + TASK_IDLE, 1, timeout, \ + __ret = schedule_timeout(__ret)) + +/** + * wait_event_idle_exclusive_timeout - sleep without load until a condition becomes true or a timeout elapses + * @wq_head: 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_IDLE) until the + * @condition evaluates to true. The @condition is checked each time + * the waitqueue @wq_head is woken up. + * + * The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag + * set thus if other processes wait on the same list, when this + * process is woken further processes are not considered. + * + * 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_idle_exclusive_timeout(wq_head, condition, timeout) \ +({ \ + long __ret = timeout; \ + might_sleep(); \ + if (!___wait_cond_timeout(condition)) \ + __ret = __wait_event_idle_exclusive_timeout(wq_head, condition, timeout);\ + __ret; \ +}) + +extern int do_wait_intr(wait_queue_head_t *, wait_queue_entry_t *); +extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *); + +#define __wait_event_interruptible_locked(wq, condition, exclusive, fn) \ +({ \ + int __ret; \ + DEFINE_WAIT(__wait); \ + if (exclusive) \ + __wait.flags |= WQ_FLAG_EXCLUSIVE; \ + do { \ + __ret = fn(&(wq), &__wait); \ + if (__ret) \ + break; \ + } 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, do_wait_intr)) + +/** + * 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, do_wait_intr_irq)) + +/** + * 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, do_wait_intr)) + +/** + * 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, do_wait_intr_irq)) + + +#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_head: 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_head 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_head, condition) \ +({ \ + int __ret = 0; \ + might_sleep(); \ + if (!(condition)) \ + __ret = __wait_event_killable(wq_head, condition); \ + __ret; \ +}) + +#define __wait_event_state(wq, condition, state) \ + ___wait_event(wq, condition, state, 0, 0, schedule()) + +/** + * wait_event_state - sleep until a condition gets true + * @wq_head: the waitqueue to wait on + * @condition: a C expression for the event to wait for + * @state: state to sleep in + * + * The process is put to sleep (@state) until the @condition evaluates to true + * or a signal is received (when allowed by @state). The @condition is checked + * each time the waitqueue @wq_head 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 + * (when allowed by @state) and 0 if @condition evaluated to true. + */ +#define wait_event_state(wq_head, condition, state) \ +({ \ + int __ret = 0; \ + might_sleep(); \ + if (!(condition)) \ + __ret = __wait_event_state(wq_head, condition, state); \ + __ret; \ +}) + +#define __wait_event_killable_timeout(wq_head, condition, timeout) \ + ___wait_event(wq_head, ___wait_cond_timeout(condition), \ + TASK_KILLABLE, 0, timeout, \ + __ret = schedule_timeout(__ret)) + +/** + * wait_event_killable_timeout - sleep until a condition gets true or a timeout elapses + * @wq_head: 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_KILLABLE) until the + * @condition evaluates to true or a kill signal is received. + * The @condition is checked each time the waitqueue @wq_head 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 kill signal. + * + * Only kill signals interrupt this process. + */ +#define wait_event_killable_timeout(wq_head, condition, timeout) \ +({ \ + long __ret = timeout; \ + might_sleep(); \ + if (!___wait_cond_timeout(condition)) \ + __ret = __wait_event_killable_timeout(wq_head, \ + condition, timeout); \ + __ret; \ +}) + + +#define __wait_event_lock_irq(wq_head, condition, lock, cmd) \ + (void)___wait_event(wq_head, 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_head: 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_head 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_head, condition, lock, cmd) \ +do { \ + if (condition) \ + break; \ + __wait_event_lock_irq(wq_head, 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_head: 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_head 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_head, condition, lock) \ +do { \ + if (condition) \ + break; \ + __wait_event_lock_irq(wq_head, condition, lock, ); \ +} while (0) + + +#define __wait_event_interruptible_lock_irq(wq_head, condition, lock, cmd) \ + ___wait_event(wq_head, 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_head: 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_head 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_head, condition, lock, cmd) \ +({ \ + int __ret = 0; \ + if (!(condition)) \ + __ret = __wait_event_interruptible_lock_irq(wq_head, \ + 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_head: 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_head 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_head, condition, lock) \ +({ \ + int __ret = 0; \ + if (!(condition)) \ + __ret = __wait_event_interruptible_lock_irq(wq_head, \ + condition, lock,); \ + __ret; \ +}) + +#define __wait_event_lock_irq_timeout(wq_head, condition, lock, timeout, state) \ + ___wait_event(wq_head, ___wait_cond_timeout(condition), \ + state, 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_head: 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_head 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_head, condition, lock, \ + timeout) \ +({ \ + long __ret = timeout; \ + if (!___wait_cond_timeout(condition)) \ + __ret = __wait_event_lock_irq_timeout( \ + wq_head, condition, lock, timeout, \ + TASK_INTERRUPTIBLE); \ + __ret; \ +}) + +#define wait_event_lock_irq_timeout(wq_head, condition, lock, timeout) \ +({ \ + long __ret = timeout; \ + if (!___wait_cond_timeout(condition)) \ + __ret = __wait_event_lock_irq_timeout( \ + wq_head, condition, lock, timeout, \ + TASK_UNINTERRUPTIBLE); \ + __ret; \ +}) + +/* + * Waitqueues which are removed from the waitqueue_head at wakeup time + */ +void prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state); +bool prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state); +long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state); +void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry); +long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout); +int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key); +int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key); + +#define DEFINE_WAIT_FUNC(name, function) \ + struct wait_queue_entry name = { \ + .private = current, \ + .func = function, \ + .entry = LIST_HEAD_INIT((name).entry), \ + } + +#define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function) + +#define init_wait(wait) \ + do { \ + (wait)->private = current; \ + (wait)->func = autoremove_wake_function; \ + INIT_LIST_HEAD(&(wait)->entry); \ + (wait)->flags = 0; \ + } while (0) + +typedef int (*task_call_f)(struct task_struct *p, void *arg); +extern int task_call_func(struct task_struct *p, task_call_f func, void *arg); + +#endif /* _LINUX_WAIT_H */ |