android_kernel_motorola_sm6225/include/asm-generic/mutex-null.h
Ingo Molnar 620a6fd185 [PATCH] mutex subsystem, add asm-generic/mutex-[dec|xchg|null].h implementations
Add three (generic) mutex fastpath implementations.

The mutex-xchg.h implementation is atomic_xchg() based, and should
work fine on every architecture.

The mutex-dec.h implementation is atomic_dec_return() based - this
one too should work on every architecture, but might not perform the
most optimally on architectures that have no atomic-dec/inc instructions.

The mutex-null.h implementation forces all calls into the slowpath. This
is used for mutex debugging, but it can also be used on platforms that do
not want (or need) a fastpath at all.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
2006-01-09 15:59:17 -08:00

24 lines
806 B
C

/*
* asm-generic/mutex-null.h
*
* Generic implementation of the mutex fastpath, based on NOP :-)
*
* This is used by the mutex-debugging infrastructure, but it can also
* be used by architectures that (for whatever reason) want to use the
* spinlock based slowpath.
*/
#ifndef _ASM_GENERIC_MUTEX_NULL_H
#define _ASM_GENERIC_MUTEX_NULL_H
/* extra parameter only needed for mutex debugging: */
#ifndef __IP__
# define __IP__
#endif
#define __mutex_fastpath_lock(count, fail_fn) fail_fn(count __RET_IP__)
#define __mutex_fastpath_lock_retval(count, fail_fn) fail_fn(count __RET_IP__)
#define __mutex_fastpath_unlock(count, fail_fn) fail_fn(count __RET_IP__)
#define __mutex_fastpath_trylock(count, fail_fn) fail_fn(count)
#define __mutex_slowpath_needs_to_unlock() 1
#endif