forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
45 lines
1.5 KiB
45 lines
1.5 KiB
/* rwsem-spinlock.h: fallback C implementation |
|
* |
|
* Copyright (c) 2001 David Howells ([email protected]). |
|
* - Derived partially from ideas by Andrea Arcangeli <[email protected]> |
|
* - Derived also from comments by Linus |
|
*/ |
|
|
|
#ifndef _LINUX_RWSEM_SPINLOCK_H |
|
#define _LINUX_RWSEM_SPINLOCK_H |
|
|
|
#ifndef _LINUX_RWSEM_H |
|
#error "please don't include linux/rwsem-spinlock.h directly, use linux/rwsem.h instead" |
|
#endif |
|
|
|
#ifdef __KERNEL__ |
|
/* |
|
* the rw-semaphore definition |
|
* - if count is 0 then there are no active readers or writers |
|
* - if count is +ve then that is the number of active readers |
|
* - if count is -1 then there is one active writer |
|
* - if wait_list is not empty, then there are processes waiting for the semaphore |
|
*/ |
|
struct rw_semaphore { |
|
__s32 count; |
|
raw_spinlock_t wait_lock; |
|
struct list_head wait_list; |
|
#ifdef CONFIG_DEBUG_LOCK_ALLOC |
|
struct lockdep_map dep_map; |
|
#endif |
|
}; |
|
|
|
#define RWSEM_UNLOCKED_VALUE 0x00000000 |
|
|
|
extern void __down_read(struct rw_semaphore *sem); |
|
extern int __down_read_trylock(struct rw_semaphore *sem); |
|
extern void __down_write(struct rw_semaphore *sem); |
|
extern int __must_check __down_write_killable(struct rw_semaphore *sem); |
|
extern int __down_write_trylock(struct rw_semaphore *sem); |
|
extern void __up_read(struct rw_semaphore *sem); |
|
extern void __up_write(struct rw_semaphore *sem); |
|
extern void __downgrade_write(struct rw_semaphore *sem); |
|
extern int rwsem_is_locked(struct rw_semaphore *sem); |
|
|
|
#endif /* __KERNEL__ */ |
|
#endif /* _LINUX_RWSEM_SPINLOCK_H */
|
|
|