From 620a6fd185c084aa617c411f711533f01ea673c9 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 9 Jan 2006 15:59:17 -0800 Subject: [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 Signed-off-by: Arjan van de Ven --- include/asm-generic/mutex-null.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) create mode 100644 include/asm-generic/mutex-null.h (limited to 'include/asm-generic/mutex-null.h') diff --git a/include/asm-generic/mutex-null.h b/include/asm-generic/mutex-null.h new file mode 100644 index 000000000000..5cf8b7ce0c45 --- /dev/null +++ b/include/asm-generic/mutex-null.h @@ -0,0 +1,24 @@ +/* + * 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 -- cgit v1.2.3