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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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/* * Linux wait-bit related types and methods: */#include <linux/wait.h>
struct wait_bit_key { unsigned long *flags; int bit_nr; unsigned long timeout;};
struct wait_bit_queue_entry { struct wait_bit_key key; struct wait_queue_entry wq_entry;};
#define __WAIT_BIT_KEY_INITIALIZER(word, bit) \ { .flags = word, .bit_nr = bit, }
typedef int wait_bit_action_f(struct wait_bit_key *key, int mode);
void __wake_up_bit(struct wait_queue_head *wq_head, unsigned long *word, int bit);int __wait_on_bit(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_entry, wait_bit_action_f *action, unsigned int mode);int __wait_on_bit_lock(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_entry, wait_bit_action_f *action, unsigned int mode);void wake_up_bit(unsigned long *word, int bit);int out_of_line_wait_on_bit(unsigned long *word, int, wait_bit_action_f *action, unsigned int mode);int out_of_line_wait_on_bit_timeout(unsigned long *word, int, wait_bit_action_f *action, unsigned int mode, unsigned long timeout);int out_of_line_wait_on_bit_lock(unsigned long *word, int, wait_bit_action_f *action, unsigned int mode);struct wait_queue_head *bit_waitqueue(unsigned long *word, int bit);extern void __init wait_bit_init(void);
int wake_bit_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
#define DEFINE_WAIT_BIT(name, word, bit) \ struct wait_bit_queue_entry name = { \ .key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \ .wq_entry = { \ .private = current, \ .func = wake_bit_function, \ .entry = \ LIST_HEAD_INIT((name).wq_entry.entry), \ }, \ }
extern int bit_wait(struct wait_bit_key *key, int mode);extern int bit_wait_io(struct wait_bit_key *key, int mode);extern int bit_wait_timeout(struct wait_bit_key *key, int mode);
/** * wait_on_bit - wait for a bit to be cleared * @word: the address containing the bit being waited on * @bit: the bit at that address being waited on * @mode: the task state to sleep in * * Wait for the given bit in an unsigned long or bitmap (see DECLARE_BITMAP()) * to be cleared. The clearing of the bit must be signalled with * wake_up_bit(), often as clear_and_wake_up_bit(). * * The process will wait on a waitqueue selected by hash from a shared * pool. It will only be woken on a wake_up for the target bit, even * if other processes on the same queue are waiting for other bits. * * Returned value will be zero if the bit was cleared in which case the * call has ACQUIRE semantics, or %-EINTR if the process received a * signal and the mode permitted wake up on that signal. */static inline intwait_on_bit(unsigned long *word, int bit, unsigned mode){ might_sleep(); if (!test_bit_acquire(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 address containing the bit being waited on * @bit: the bit at that address being waited on * @mode: the task state to sleep in * * Wait for the given bit in an unsigned long or bitmap (see DECLARE_BITMAP()) * to be cleared. The clearing of the bit must be signalled with * wake_up_bit(), often as clear_and_wake_up_bit(). * * 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 in which case the * call has ACQUIRE semantics, or %-EINTR if the process received a * signal and the mode permitted wake up on that signal. */static inline intwait_on_bit_io(unsigned long *word, int bit, unsigned mode){ might_sleep(); if (!test_bit_acquire(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 to elapse * @word: the address containing the bit being waited on * @bit: the bit at that address being waited on * @mode: the task state to sleep in * @timeout: timeout, in jiffies * * Wait for the given bit in an unsigned long or bitmap (see * DECLARE_BITMAP()) to be cleared, or for a timeout to expire. The * clearing of the bit must be signalled with wake_up_bit(), often as * clear_and_wake_up_bit(). * * This is similar to wait_on_bit(), except it also takes a timeout * parameter. * * Returned value will be zero if the bit was cleared in which case the * call has ACQUIRE semantics, or %-EINTR if the process received a * signal and the mode permitted wake up on that signal, or %-EAGAIN if the * timeout elapsed. */static inline intwait_on_bit_timeout(unsigned long *word, int bit, unsigned mode, unsigned long timeout){ might_sleep(); if (!test_bit_acquire(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 address containing the bit waited on * @bit: the bit at that address being waited on * @action: the function used to sleep, which may take special actions * @mode: the task state to sleep in * * Wait for the given bit in an unsigned long or bitmap (see DECLARE_BITMAP()) * to be cleared. The clearing of the bit must be signalled with * wake_up_bit(), often as clear_and_wake_up_bit(). * * This is similar to wait_on_bit(), but calls @action() instead of * schedule() for the actual waiting. * * Returned value will be zero if the bit was cleared in which case the * call has ACQUIRE semantics, or the error code returned by @action if * that call returned non-zero. */static inline intwait_on_bit_action(unsigned long *word, int bit, wait_bit_action_f *action, unsigned mode){ might_sleep(); if (!test_bit_acquire(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, then set it * @word: the address containing the bit being waited on * @bit: the bit of the word being waited on and set * @mode: the task state to sleep in * * Wait for the given bit in an unsigned long or bitmap (see * DECLARE_BITMAP()) to be cleared. The clearing of the bit must be * signalled with wake_up_bit(), often as clear_and_wake_up_bit(). As * soon as it is clear, atomically set it and return. * * This is similar to wait_on_bit(), but sets the bit before returning. * * Returned value will be zero if the bit was successfully set in which * case the call has the same memory sequencing semantics as * test_and_clear_bit(), or %-EINTR if the process received a signal and * the mode permitted wake up on that signal. */static inline intwait_on_bit_lock(unsigned long *word, int bit, unsigned mode){ might_sleep(); if (!test_and_set_bit(bit, word)) return 0; return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode);}
/** * wait_on_bit_lock_io - wait for a bit to be cleared, then set it * @word: the address containing the bit being waited on * @bit: the bit of the word being waited on and set * @mode: the task state to sleep in * * Wait for the given bit in an unsigned long or bitmap (see * DECLARE_BITMAP()) to be cleared. The clearing of the bit must be * signalled with wake_up_bit(), often as clear_and_wake_up_bit(). As * soon as it is clear, atomically set it and return. * * This is similar to wait_on_bit_lock(), but calls io_schedule() instead * of schedule(). * * 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 intwait_on_bit_lock_io(unsigned long *word, int bit, unsigned mode){ might_sleep(); if (!test_and_set_bit(bit, word)) return 0; return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode);}
/** * wait_on_bit_lock_action - wait for a bit to be cleared, then set it * @word: the address containing the bit being waited on * @bit: the bit of the word being waited on and set * @action: the function used to sleep, which may take special actions * @mode: the task state to sleep in * * This is similar to wait_on_bit_lock(), but calls @action() instead of * schedule() for the actual waiting. * * Returned value will be zero if the bit was successfully set in which * case the call has the same memory sequencing semantics as * test_and_clear_bit(), or the error code returned by @action if that * call returned non-zero. */static inline intwait_on_bit_lock_action(unsigned long *word, int bit, wait_bit_action_f *action, unsigned mode){ might_sleep(); if (!test_and_set_bit(bit, word)) return 0; return out_of_line_wait_on_bit_lock(word, bit, action, mode);}
extern void init_wait_var_entry(struct wait_bit_queue_entry *wbq_entry, void *var, int flags);extern void wake_up_var(void *var);extern wait_queue_head_t *__var_waitqueue(void *p);
#define ___wait_var_event(var, condition, state, exclusive, ret, cmd) \({ \ __label__ __out; \ struct wait_queue_head *__wq_head = __var_waitqueue(var); \ struct wait_bit_queue_entry __wbq_entry; \ long __ret = ret; /* explicit shadow */ \ \ init_wait_var_entry(&__wbq_entry, var, \ exclusive ? WQ_FLAG_EXCLUSIVE : 0); \ for (;;) { \ long __int = prepare_to_wait_event(__wq_head, \ &__wbq_entry.wq_entry, \ state); \ if (condition) \ break; \ \ if (___wait_is_interruptible(state) && __int) { \ __ret = __int; \ goto __out; \ } \ \ cmd; \ } \ finish_wait(__wq_head, &__wbq_entry.wq_entry); \__out: __ret; \})
#define __wait_var_event(var, condition) \ ___wait_var_event(var, condition, TASK_UNINTERRUPTIBLE, 0, 0, \ schedule())#define __wait_var_event_io(var, condition) \ ___wait_var_event(var, condition, TASK_UNINTERRUPTIBLE, 0, 0, \ io_schedule())
/** * wait_var_event - wait for a variable to be updated and notified * @var: the address of variable being waited on * @condition: the condition to wait for * * Wait for a @condition to be true, only re-checking when a wake up is * received for the given @var (an arbitrary kernel address which need * not be directly related to the given condition, but usually is). * * The process will wait on a waitqueue selected by hash from a shared * pool. It will only be woken on a wake_up for the given address. * * The condition should normally use smp_load_acquire() or a similarly * ordered access to ensure that any changes to memory made before the * condition became true will be visible after the wait completes. */#define wait_var_event(var, condition) \do { \ might_sleep(); \ if (condition) \ break; \ __wait_var_event(var, condition); \} while (0)
/** * wait_var_event_io - wait for a variable to be updated and notified * @var: the address of variable being waited on * @condition: the condition to wait for * * Wait for an IO related @condition to be true, only re-checking when a * wake up is received for the given @var (an arbitrary kernel address * which need not be directly related to the given condition, but * usually is). * * The process will wait on a waitqueue selected by hash from a shared * pool. It will only be woken on a wake_up for the given address. * * This is similar to wait_var_event(), but calls io_schedule() instead * of schedule(). * * The condition should normally use smp_load_acquire() or a similarly * ordered access to ensure that any changes to memory made before the * condition became true will be visible after the wait completes. */#define wait_var_event_io(var, condition) \do { \ might_sleep(); \ if (condition) \ break; \ __wait_var_event_io(var, condition); \} while (0)
#define __wait_var_event_killable(var, condition) \ ___wait_var_event(var, condition, TASK_KILLABLE, 0, 0, \ schedule())
/** * wait_var_event_killable - wait for a variable to be updated and notified * @var: the address of variable being waited on * @condition: the condition to wait for * * Wait for a @condition to be true or a fatal signal to be received, * only re-checking the condition when a wake up is received for the given * @var (an arbitrary kernel address which need not be directly related * to the given condition, but usually is). * * This is similar to wait_var_event() but returns a value which is * 0 if the condition became true, or %-ERESTARTSYS if a fatal signal * was received. * * The condition should normally use smp_load_acquire() or a similarly * ordered access to ensure that any changes to memory made before the * condition became true will be visible after the wait completes. */#define wait_var_event_killable(var, condition) \({ \ int __ret = 0; \ might_sleep(); \ if (!(condition)) \ __ret = __wait_var_event_killable(var, condition); \ __ret; \})
#define __wait_var_event_timeout(var, condition, timeout) \ ___wait_var_event(var, ___wait_cond_timeout(condition), \ TASK_UNINTERRUPTIBLE, 0, timeout, \ __ret = schedule_timeout(__ret))
/** * wait_var_event_timeout - wait for a variable to be updated or a timeout to expire * @var: the address of variable being waited on * @condition: the condition to wait for * @timeout: maximum time to wait in jiffies * * Wait for a @condition to be true or a timeout to expire, only * re-checking the condition when a wake up is received for the given * @var (an arbitrary kernel address which need not be directly related * to the given condition, but usually is). * * This is similar to wait_var_event() but returns a value which is 0 if * the timeout expired and the condition was still false, or the * remaining time left in the timeout (but at least 1) if the condition * was found to be true. * * The condition should normally use smp_load_acquire() or a similarly * ordered access to ensure that any changes to memory made before the * condition became true will be visible after the wait completes. */#define wait_var_event_timeout(var, condition, timeout) \({ \ long __ret = timeout; \ might_sleep(); \ if (!___wait_cond_timeout(condition)) \ __ret = __wait_var_event_timeout(var, condition, timeout); \ __ret; \})
#define __wait_var_event_interruptible(var, condition) \ ___wait_var_event(var, condition, TASK_INTERRUPTIBLE, 0, 0, \ schedule())
/** * wait_var_event_interruptible - wait for a variable to be updated and notified * @var: the address of variable being waited on * @condition: the condition to wait for * * Wait for a @condition to be true or a signal to be received, only * re-checking the condition when a wake up is received for the given * @var (an arbitrary kernel address which need not be directly related * to the given condition, but usually is). * * This is similar to wait_var_event() but returns a value which is 0 if * the condition became true, or %-ERESTARTSYS if a signal was received. * * The condition should normally use smp_load_acquire() or a similarly * ordered access to ensure that any changes to memory made before the * condition became true will be visible after the wait completes. */#define wait_var_event_interruptible(var, condition) \({ \ int __ret = 0; \ might_sleep(); \ if (!(condition)) \ __ret = __wait_var_event_interruptible(var, condition); \ __ret; \})
/** * wait_var_event_any_lock - wait for a variable to be updated under a lock * @var: the address of the variable being waited on * @condition: condition to wait for * @lock: the object that is locked to protect updates to the variable * @type: prefix on lock and unlock operations * @state: waiting state, %TASK_UNINTERRUPTIBLE etc. * * Wait for a condition which can only be reliably tested while holding * a lock. The variables assessed in the condition will normal be updated * under the same lock, and the wake up should be signalled with * wake_up_var_locked() under the same lock. * * This is similar to wait_var_event(), but assumes a lock is held * while calling this function and while updating the variable. * * This must be called while the given lock is held and the lock will be * dropped when schedule() is called to wait for a wake up, and will be * reclaimed before testing the condition again. The functions used to * unlock and lock the object are constructed by appending _unlock and _lock * to @type. * * Return %-ERESTARTSYS if a signal arrives which is allowed to interrupt * the wait according to @state. */#define wait_var_event_any_lock(var, condition, lock, type, state) \({ \ int __ret = 0; \ if (!(condition)) \ __ret = ___wait_var_event(var, condition, state, 0, 0, \ type ## _unlock(lock); \ schedule(); \ type ## _lock(lock)); \ __ret; \})
/** * wait_var_event_spinlock - wait for a variable to be updated under a spinlock * @var: the address of the variable being waited on * @condition: condition to wait for * @lock: the spinlock which protects updates to the variable * * Wait for a condition which can only be reliably tested while holding * a spinlock. The variables assessed in the condition will normal be updated * under the same spinlock, and the wake up should be signalled with * wake_up_var_locked() under the same spinlock. * * This is similar to wait_var_event(), but assumes a spinlock is held * while calling this function and while updating the variable. * * This must be called while the given lock is held and the lock will be * dropped when schedule() is called to wait for a wake up, and will be * reclaimed before testing the condition again. */#define wait_var_event_spinlock(var, condition, lock) \ wait_var_event_any_lock(var, condition, lock, spin, TASK_UNINTERRUPTIBLE)
/** * wait_var_event_mutex - wait for a variable to be updated under a mutex * @var: the address of the variable being waited on * @condition: condition to wait for * @lock: the mutex which protects updates to the variable * * Wait for a condition which can only be reliably tested while holding * a mutex. The variables assessed in the condition will normal be * updated under the same mutex, and the wake up should be signalled * with wake_up_var_locked() under the same mutex. * * This is similar to wait_var_event(), but assumes a mutex is held * while calling this function and while updating the variable. * * This must be called while the given mutex is held and the mutex will be * dropped when schedule() is called to wait for a wake up, and will be * reclaimed before testing the condition again. */#define wait_var_event_mutex(var, condition, lock) \ wait_var_event_any_lock(var, condition, lock, mutex, TASK_UNINTERRUPTIBLE)
/** * wake_up_var_protected - wake up waiters for a variable asserting that it is safe * @var: the address of the variable being waited on * @cond: the condition which afirms this is safe * * When waking waiters which use wait_var_event_any_lock() the waker must be * holding the reelvant lock to avoid races. This version of wake_up_var() * asserts that the relevant lock is held and so no barrier is needed. * The @cond is only tested when CONFIG_LOCKDEP is enabled. */#define wake_up_var_protected(var, cond) \do { \ lockdep_assert(cond); \ wake_up_var(var); \} while (0)
/** * wake_up_var_locked - wake up waiters for a variable while holding a spinlock or mutex * @var: the address of the variable being waited on * @lock: The spinlock or mutex what protects the variable * * Send a wake up for the given variable which should be waited for with * wait_var_event_spinlock() or wait_var_event_mutex(). Unlike wake_up_var(), * no extra barriers are needed as the locking provides sufficient sequencing. */#define wake_up_var_locked(var, lock) \ wake_up_var_protected(var, lockdep_is_held(lock))
/** * clear_and_wake_up_bit - clear a bit and wake up anyone waiting on that bit * @bit: the bit of the word being waited on * @word: the address containing the bit being waited on * * The designated bit is cleared and any tasks waiting in wait_on_bit() * or similar will be woken. This call has RELEASE semantics so that * any changes to memory made before this call are guaranteed to be visible * after the corresponding wait_on_bit() completes. */static inline void clear_and_wake_up_bit(int bit, unsigned long *word){ clear_bit_unlock(bit, word); /* See wake_up_bit() for which memory barrier you need to use. */ smp_mb__after_atomic(); wake_up_bit(word, bit);}
/** * test_and_clear_wake_up_bit - clear a bit if it was set: wake up anyone waiting on that bit * @bit: the bit of the word being waited on * @word: the address of memory containing that bit * * If the bit is set and can be atomically cleared, any tasks waiting in * wait_on_bit() or similar will be woken. This call has the same * complete ordering semantics as test_and_clear_bit(). Any changes to * memory made before this call are guaranteed to be visible after the * corresponding wait_on_bit() completes. * * Returns %true if the bit was successfully set and the wake up was sent. */static inline bool test_and_clear_wake_up_bit(int bit, unsigned long *word){ if (!test_and_clear_bit(bit, word)) return false; /* no extra barrier required */ wake_up_bit(word, bit); return true;}
/** * atomic_dec_and_wake_up - decrement an atomic_t and if zero, wake up waiters * @var: the variable to dec and test * * Decrements the atomic variable and if it reaches zero, send a wake_up to any * processes waiting on the variable. * * This function has the same complete ordering semantics as atomic_dec_and_test. * * Returns %true is the variable reaches zero and the wake up was sent. */
static inline bool atomic_dec_and_wake_up(atomic_t *var){ if (!atomic_dec_and_test(var)) return false; /* No extra barrier required */ wake_up_var(var); return true;}
/** * store_release_wake_up - update a variable and send a wake_up * @var: the address of the variable to be updated and woken * @val: the value to store in the variable. * * Store the given value in the variable send a wake up to any tasks * waiting on the variable. All necessary barriers are included to ensure * the task calling wait_var_event() sees the new value and all values * written to memory before this call. */#define store_release_wake_up(var, val) \do { \ smp_store_release(var, val); \ smp_mb(); \ wake_up_var(var); \} while (0)
#endif /* _LINUX_WAIT_BIT_H */