ARM: 7749/1: spinlock: retry trylock operation if strex fails on free lock
authorWill Deacon <will.deacon@arm.com>
Wed, 5 Jun 2013 10:27:26 +0000 (11:27 +0100)
committerRussell King <rmk+kernel@arm.linux.org.uk>
Mon, 17 Jun 2013 08:27:04 +0000 (09:27 +0100)
commit15e7e5c1ebf556cd620c9b091e121091ac760f6d
tree6eef89a449f0256e5c9db04f36a562c5ff1c699d
parent1aa2b3b7a6c4f3dbd3671171113a20e6a6190e3b
ARM: 7749/1: spinlock: retry trylock operation if strex fails on free lock

An exclusive store instruction may fail for reasons other than lock
contention (e.g. a cache eviction during the critical section) so, in
line with other architectures using similar exclusive instructions
(alpha, mips, powerpc), retry the trylock operation if the lock appears
to be free but the strex reported failure.

Reported-by: Tony Thompson <anthony.thompson@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
arch/arm/include/asm/spinlock.h