forked from mirrors/linux
1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
65 lines
1.8 KiB
C
65 lines
1.8 KiB
C
/* rwsem-spinlock.h: fallback C implementation
|
|
*
|
|
* Copyright (c) 2001 David Howells (dhowells@redhat.com).
|
|
* - Derived partially from ideas by Andrea Arcangeli <andrea@suse.de>
|
|
* - 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
|
|
|
|
#include <linux/spinlock.h>
|
|
#include <linux/list.h>
|
|
|
|
#ifdef __KERNEL__
|
|
|
|
#include <linux/types.h>
|
|
|
|
struct rwsem_waiter;
|
|
|
|
/*
|
|
* the rw-semaphore definition
|
|
* - if activity is 0 then there are no active readers or writers
|
|
* - if activity is +ve then that is the number of active readers
|
|
* - if activity 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 activity;
|
|
spinlock_t wait_lock;
|
|
struct list_head wait_list;
|
|
#if RWSEM_DEBUG
|
|
int debug;
|
|
#endif
|
|
};
|
|
|
|
/*
|
|
* initialisation
|
|
*/
|
|
#if RWSEM_DEBUG
|
|
#define __RWSEM_DEBUG_INIT , 0
|
|
#else
|
|
#define __RWSEM_DEBUG_INIT /* */
|
|
#endif
|
|
|
|
#define __RWSEM_INITIALIZER(name) \
|
|
{ 0, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) __RWSEM_DEBUG_INIT }
|
|
|
|
#define DECLARE_RWSEM(name) \
|
|
struct rw_semaphore name = __RWSEM_INITIALIZER(name)
|
|
|
|
extern void FASTCALL(init_rwsem(struct rw_semaphore *sem));
|
|
extern void FASTCALL(__down_read(struct rw_semaphore *sem));
|
|
extern int FASTCALL(__down_read_trylock(struct rw_semaphore *sem));
|
|
extern void FASTCALL(__down_write(struct rw_semaphore *sem));
|
|
extern int FASTCALL(__down_write_trylock(struct rw_semaphore *sem));
|
|
extern void FASTCALL(__up_read(struct rw_semaphore *sem));
|
|
extern void FASTCALL(__up_write(struct rw_semaphore *sem));
|
|
extern void FASTCALL(__downgrade_write(struct rw_semaphore *sem));
|
|
|
|
#endif /* __KERNEL__ */
|
|
#endif /* _LINUX_RWSEM_SPINLOCK_H */
|