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Commit 342e73b3 authored by Jon Loeliger's avatar Jon Loeliger Committed by Paul Mackerras
Browse files

[PATCH] powerpc: Merge asm-ppc*/rwsem.h 



Merge asm-ppc*/rwsem.h into include/asm-powerpc.
Removed smp_*mb() memory barriers from the ppc32 code
as they are now burried in the atomic_*() functions as
suggested by Paul, implemented by Arnd, and pushed out
by Becky.  I am not the droid you are looking for.

This patch depends on Becky's atomic.h merge patch.

Signed-off-by: default avatarJon Loeliger <jdl@freescale.com>
Signed-off-by: default avatarKumar Gala <kumar.gala@freescale.com>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent feaf7cf1

include/asm-ppc64/rwsem.h→include/asm-powerpc/rwsem.h

+7 −11
Original line number Diff line number Diff line 
#ifndef _ASM_POWERPC_RWSEM_H

#define _ASM_POWERPC_RWSEM_H



#ifdef __KERNEL__



/*

 * include/asm-ppc64/rwsem.h: R/W semaphores for PPC using the stuff

 * in lib/rwsem.c.  Adapted largely from include/asm-i386/rwsem.h

 * by Paul Mackerras <paulus@samba.org>.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version

 * 2 of the License, or (at your option) any later version.

 */



#ifndef _PPC64_RWSEM_H

#define _PPC64_RWSEM_H



#ifdef __KERNEL__

#include <linux/list.h>

#include <linux/spinlock.h>

#include <asm/atomic.h>
@@ -164,4 +160,4 @@ static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem) 
}



#endif	/* __KERNEL__ */

#endif /* _PPC_RWSEM_XADD_H */
 
#endif	/* _ASM_POWERPC_RWSEM_H */

include/asm-ppc/rwsem.h

deleted100644 → 0
+0 −172
Original line number Diff line number Diff line 
/*

 * include/asm-ppc/rwsem.h: R/W semaphores for PPC using the stuff

 * in lib/rwsem.c.  Adapted largely from include/asm-i386/rwsem.h

 * by Paul Mackerras <paulus@samba.org>.

 */



#ifndef _PPC_RWSEM_H

#define _PPC_RWSEM_H



#ifdef __KERNEL__

#include <linux/list.h>

#include <linux/spinlock.h>

#include <asm/atomic.h>

#include <asm/system.h>



/*

 * the semaphore definition

 */

struct rw_semaphore {

	/* XXX this should be able to be an atomic_t  -- paulus */

	signed long		count;

#define RWSEM_UNLOCKED_VALUE		0x00000000

#define RWSEM_ACTIVE_BIAS		0x00000001

#define RWSEM_ACTIVE_MASK		0x0000ffff

#define RWSEM_WAITING_BIAS		(-0x00010000)

#define RWSEM_ACTIVE_READ_BIAS		RWSEM_ACTIVE_BIAS

#define RWSEM_ACTIVE_WRITE_BIAS		(RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)

	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) \

	{ RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, \

	  LIST_HEAD_INIT((name).wait_list) \

	  __RWSEM_DEBUG_INIT }



#define DECLARE_RWSEM(name)		\

	struct rw_semaphore name = __RWSEM_INITIALIZER(name)



extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem);

extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem);

extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem);

extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem);



static inline void init_rwsem(struct rw_semaphore *sem)

{

	sem->count = RWSEM_UNLOCKED_VALUE;

	spin_lock_init(&sem->wait_lock);

	INIT_LIST_HEAD(&sem->wait_list);

#if RWSEM_DEBUG

	sem->debug = 0;

#endif

}



/*

 * lock for reading

 */

static inline void __down_read(struct rw_semaphore *sem)

{

	if (atomic_inc_return((atomic_t *)(&sem->count)) > 0)

		smp_wmb();

	else

		rwsem_down_read_failed(sem);

}



static inline int __down_read_trylock(struct rw_semaphore *sem)

{

	int tmp;



	while ((tmp = sem->count) >= 0) {

		if (tmp == cmpxchg(&sem->count, tmp,

				   tmp + RWSEM_ACTIVE_READ_BIAS)) {

			smp_wmb();

			return 1;

		}

	}

	return 0;

}



/*

 * lock for writing

 */

static inline void __down_write(struct rw_semaphore *sem)

{

	int tmp;



	tmp = atomic_add_return(RWSEM_ACTIVE_WRITE_BIAS,

				(atomic_t *)(&sem->count));

	if (tmp == RWSEM_ACTIVE_WRITE_BIAS)

		smp_wmb();

	else

		rwsem_down_write_failed(sem);

}



static inline int __down_write_trylock(struct rw_semaphore *sem)

{

	int tmp;



	tmp = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,

		      RWSEM_ACTIVE_WRITE_BIAS);

	smp_wmb();

	return tmp == RWSEM_UNLOCKED_VALUE;

}



/*

 * unlock after reading

 */

static inline void __up_read(struct rw_semaphore *sem)

{

	int tmp;



	smp_wmb();

	tmp = atomic_dec_return((atomic_t *)(&sem->count));

	if (tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0)

		rwsem_wake(sem);

}



/*

 * unlock after writing

 */

static inline void __up_write(struct rw_semaphore *sem)

{

	smp_wmb();

	if (atomic_sub_return(RWSEM_ACTIVE_WRITE_BIAS,

			      (atomic_t *)(&sem->count)) < 0)

		rwsem_wake(sem);

}



/*

 * implement atomic add functionality

 */

static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)

{

	atomic_add(delta, (atomic_t *)(&sem->count));

}



/*

 * downgrade write lock to read lock

 */

static inline void __downgrade_write(struct rw_semaphore *sem)

{

	int tmp;



	smp_wmb();

	tmp = atomic_add_return(-RWSEM_WAITING_BIAS, (atomic_t *)(&sem->count));

	if (tmp < 0)

		rwsem_downgrade_wake(sem);

}



/*

 * implement exchange and add functionality

 */

static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)

{

	smp_mb();

	return atomic_add_return(delta, (atomic_t *)(&sem->count));

}



#endif /* __KERNEL__ */

#endif /* _PPC_RWSEM_XADD_H */