From: Christian Borntraeger Date: Mon, 24 Nov 2014 09:53:11 +0000 (+0100) Subject: arm64/spinlock: Replace ACCESS_ONCE READ_ONCE X-Git-Tag: firefly_0821_release~176^2~2600^2~2 X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=af2e7aaed1ccf30e61af3e096ac2c7df2f2d6c2a;p=firefly-linux-kernel-4.4.55.git arm64/spinlock: Replace ACCESS_ONCE READ_ONCE ACCESS_ONCE does not work reliably on non-scalar types. For example gcc 4.6 and 4.7 might remove the volatile tag for such accesses during the SRA (scalar replacement of aggregates) step (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145) Change the spinlock code to replace ACCESS_ONCE with READ_ONCE. Signed-off-by: Christian Borntraeger Acked-by: Paul E. McKenney --- diff --git a/arch/arm64/include/asm/spinlock.h b/arch/arm64/include/asm/spinlock.h index c45b7b1b7197..cee128732435 100644 --- a/arch/arm64/include/asm/spinlock.h +++ b/arch/arm64/include/asm/spinlock.h @@ -99,12 +99,12 @@ static inline int arch_spin_value_unlocked(arch_spinlock_t lock) static inline int arch_spin_is_locked(arch_spinlock_t *lock) { - return !arch_spin_value_unlocked(ACCESS_ONCE(*lock)); + return !arch_spin_value_unlocked(READ_ONCE(*lock)); } static inline int arch_spin_is_contended(arch_spinlock_t *lock) { - arch_spinlock_t lockval = ACCESS_ONCE(*lock); + arch_spinlock_t lockval = READ_ONCE(*lock); return (lockval.next - lockval.owner) > 1; } #define arch_spin_is_contended arch_spin_is_contended