arm64: cmpxchg: avoid memory barrier on comparison failure
authorWill Deacon <will.deacon@arm.com>
Fri, 29 May 2015 13:47:59 +0000 (14:47 +0100)
committerWill Deacon <will.deacon@arm.com>
Mon, 27 Jul 2015 14:28:52 +0000 (15:28 +0100)
commit4e39715f4b5cb3b44576fedb2d38aca87de3cf48
tree1e4c60ef5714188ba60fe309c7feada21dcff076
parent0bc671d3f4bee9c31110d096ada0de52380e693d
arm64: cmpxchg: avoid memory barrier on comparison failure

cmpxchg doesn't require memory barrier semantics when the value
comparison fails, so make the barrier conditional on success.

Reviewed-by: Steve Capper <steve.capper@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
arch/arm64/include/asm/atomic_ll_sc.h