forked from luck/tmp_suning_uos_patched
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!
116 lines
2.3 KiB
C
116 lines
2.3 KiB
C
/* rwsem.h: R/W semaphores, public interface
|
|
*
|
|
* Written by David Howells (dhowells@redhat.com).
|
|
* Derived from asm-i386/semaphore.h
|
|
*/
|
|
|
|
#ifndef _LINUX_RWSEM_H
|
|
#define _LINUX_RWSEM_H
|
|
|
|
#include <linux/linkage.h>
|
|
|
|
#define RWSEM_DEBUG 0
|
|
|
|
#ifdef __KERNEL__
|
|
|
|
#include <linux/config.h>
|
|
#include <linux/types.h>
|
|
#include <linux/kernel.h>
|
|
#include <asm/system.h>
|
|
#include <asm/atomic.h>
|
|
|
|
struct rw_semaphore;
|
|
|
|
#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
|
|
#include <linux/rwsem-spinlock.h> /* use a generic implementation */
|
|
#else
|
|
#include <asm/rwsem.h> /* use an arch-specific implementation */
|
|
#endif
|
|
|
|
#ifndef rwsemtrace
|
|
#if RWSEM_DEBUG
|
|
extern void FASTCALL(rwsemtrace(struct rw_semaphore *sem, const char *str));
|
|
#else
|
|
#define rwsemtrace(SEM,FMT)
|
|
#endif
|
|
#endif
|
|
|
|
/*
|
|
* lock for reading
|
|
*/
|
|
static inline void down_read(struct rw_semaphore *sem)
|
|
{
|
|
might_sleep();
|
|
rwsemtrace(sem,"Entering down_read");
|
|
__down_read(sem);
|
|
rwsemtrace(sem,"Leaving down_read");
|
|
}
|
|
|
|
/*
|
|
* trylock for reading -- returns 1 if successful, 0 if contention
|
|
*/
|
|
static inline int down_read_trylock(struct rw_semaphore *sem)
|
|
{
|
|
int ret;
|
|
rwsemtrace(sem,"Entering down_read_trylock");
|
|
ret = __down_read_trylock(sem);
|
|
rwsemtrace(sem,"Leaving down_read_trylock");
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* lock for writing
|
|
*/
|
|
static inline void down_write(struct rw_semaphore *sem)
|
|
{
|
|
might_sleep();
|
|
rwsemtrace(sem,"Entering down_write");
|
|
__down_write(sem);
|
|
rwsemtrace(sem,"Leaving down_write");
|
|
}
|
|
|
|
/*
|
|
* trylock for writing -- returns 1 if successful, 0 if contention
|
|
*/
|
|
static inline int down_write_trylock(struct rw_semaphore *sem)
|
|
{
|
|
int ret;
|
|
rwsemtrace(sem,"Entering down_write_trylock");
|
|
ret = __down_write_trylock(sem);
|
|
rwsemtrace(sem,"Leaving down_write_trylock");
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* release a read lock
|
|
*/
|
|
static inline void up_read(struct rw_semaphore *sem)
|
|
{
|
|
rwsemtrace(sem,"Entering up_read");
|
|
__up_read(sem);
|
|
rwsemtrace(sem,"Leaving up_read");
|
|
}
|
|
|
|
/*
|
|
* release a write lock
|
|
*/
|
|
static inline void up_write(struct rw_semaphore *sem)
|
|
{
|
|
rwsemtrace(sem,"Entering up_write");
|
|
__up_write(sem);
|
|
rwsemtrace(sem,"Leaving up_write");
|
|
}
|
|
|
|
/*
|
|
* downgrade write lock to read lock
|
|
*/
|
|
static inline void downgrade_write(struct rw_semaphore *sem)
|
|
{
|
|
rwsemtrace(sem,"Entering downgrade_write");
|
|
__downgrade_write(sem);
|
|
rwsemtrace(sem,"Leaving downgrade_write");
|
|
}
|
|
|
|
#endif /* __KERNEL__ */
|
|
#endif /* _LINUX_RWSEM_H */
|