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/* rwsem.h: R/W semaphores, public interface

 *

 * Written by David Howells (dhowells@redhat.com).

 * Derived from asm-i386/semaphore.h

 *

 * Trylock by Brian Watson (Brian.J.Watson@compaq.com).

 */

#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)

{

        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)

{

        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");

}

#endif /* __KERNEL__ */

#endif /* _LINUX_RWSEM_H */