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Commit d6a4c847 authored by Becky Bruce's avatar Becky Bruce Committed by Paul Mackerras
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[PATCH] powerpc: merge semaphore.h 



powerpc: Merge semaphore.h

Adopted the ppc64 version of semaphore.h.  The 32-bit version used
smp_wmb(), but recent updates to atomic.h mean this is no longer required.
The 64-bit version made use of unlikely(), which has been retained in the
combined version.

This patch requires the recent atomic.h patch.

Signed-off-by: default avatarBecky Bruce <becky.bruce@freescale.com>
Signed-off-by: default avatarKumar Gala <kumar.gala@freescale.com>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 342e73b3

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

+3 −3
Original line number Diff line number Diff line 
#ifndef _PPC64_SEMAPHORE_H

#define _PPC64_SEMAPHORE_H

#ifndef _ASM_POWERPC_SEMAPHORE_H

#define _ASM_POWERPC_SEMAPHORE_H



/*

 * Remove spinlock-based RW semaphores; RW semaphore definitions are
@@ -95,4 +95,4 @@ static inline void up(struct semaphore * sem) 


#endif /* __KERNEL__ */



#endif /* !(_PPC64_SEMAPHORE_H) */
 
#endif /* _ASM_POWERPC_SEMAPHORE_H */

include/asm-ppc/semaphore.h

deleted100644 → 0
+0 −111
Original line number Diff line number Diff line 
#ifndef _PPC_SEMAPHORE_H

#define _PPC_SEMAPHORE_H



/*

 * Swiped from asm-sparc/semaphore.h and modified

 * -- Cort (cort@cs.nmt.edu)

 *

 * Stole some rw spinlock-based semaphore stuff from asm-alpha/semaphore.h

 * -- Ani Joshi (ajoshi@unixbox.com)

 *

 * Remove spinlock-based RW semaphores; RW semaphore definitions are

 * now in rwsem.h and we use the generic lib/rwsem.c implementation.

 * Rework semaphores to use atomic_dec_if_positive.

 * -- Paul Mackerras (paulus@samba.org)

 */



#ifdef __KERNEL__



#include <asm/atomic.h>

#include <asm/system.h>

#include <linux/wait.h>

#include <linux/rwsem.h>



struct semaphore {

	/*

	 * Note that any negative value of count is equivalent to 0,

	 * but additionally indicates that some process(es) might be

	 * sleeping on `wait'.

	 */

	atomic_t count;

	wait_queue_head_t wait;

};



#define __SEMAPHORE_INITIALIZER(name, n)				\

{									\

	.count		= ATOMIC_INIT(n),				\

	.wait		= __WAIT_QUEUE_HEAD_INITIALIZER((name).wait)	\

}



#define __MUTEX_INITIALIZER(name) \

	__SEMAPHORE_INITIALIZER(name, 1)



#define __DECLARE_SEMAPHORE_GENERIC(name, count) \

	struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)



#define DECLARE_MUTEX(name)		__DECLARE_SEMAPHORE_GENERIC(name, 1)

#define DECLARE_MUTEX_LOCKED(name)	__DECLARE_SEMAPHORE_GENERIC(name, 0)



static inline void sema_init (struct semaphore *sem, int val)

{

	atomic_set(&sem->count, val);

	init_waitqueue_head(&sem->wait);

}



static inline void init_MUTEX (struct semaphore *sem)

{

	sema_init(sem, 1);

}



static inline void init_MUTEX_LOCKED (struct semaphore *sem)

{

	sema_init(sem, 0);

}



extern void __down(struct semaphore * sem);

extern int  __down_interruptible(struct semaphore * sem);

extern void __up(struct semaphore * sem);



extern inline void down(struct semaphore * sem)

{

	might_sleep();



	/*

	 * Try to get the semaphore, take the slow path if we fail.

	 */

	if (atomic_dec_return(&sem->count) < 0)

		__down(sem);

	smp_wmb();

}



extern inline int down_interruptible(struct semaphore * sem)

{

	int ret = 0;



	might_sleep();



	if (atomic_dec_return(&sem->count) < 0)

		ret = __down_interruptible(sem);

	smp_wmb();

	return ret;

}



extern inline int down_trylock(struct semaphore * sem)

{

	int ret;



	ret = atomic_dec_if_positive(&sem->count) < 0;

	smp_wmb();

	return ret;

}



extern inline void up(struct semaphore * sem)

{

	smp_wmb();

	if (atomic_inc_return(&sem->count) <= 0)

		__up(sem);

}



#endif /* __KERNEL__ */



#endif /* !(_PPC_SEMAPHORE_H) */