620a6fd185
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>
24 lines
806 B
C
24 lines
806 B
C
/*
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* asm-generic/mutex-null.h
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*
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* Generic implementation of the mutex fastpath, based on NOP :-)
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*
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* This is used by the mutex-debugging infrastructure, but it can also
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* be used by architectures that (for whatever reason) want to use the
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* spinlock based slowpath.
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*/
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#ifndef _ASM_GENERIC_MUTEX_NULL_H
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#define _ASM_GENERIC_MUTEX_NULL_H
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/* extra parameter only needed for mutex debugging: */
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#ifndef __IP__
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# define __IP__
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#endif
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#define __mutex_fastpath_lock(count, fail_fn) fail_fn(count __RET_IP__)
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#define __mutex_fastpath_lock_retval(count, fail_fn) fail_fn(count __RET_IP__)
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#define __mutex_fastpath_unlock(count, fail_fn) fail_fn(count __RET_IP__)
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#define __mutex_fastpath_trylock(count, fail_fn) fail_fn(count)
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#define __mutex_slowpath_needs_to_unlock() 1
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#endif
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