Messages in this thread Patch in this message | | | From | Christian Borntraeger <> | Subject | [PATCH 6/9] arm64/spinlock: Replace ACCESS_ONCE READ_ONCE | Date | Wed, 3 Dec 2014 23:30:18 +0100 |
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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 <borntraeger@de.ibm.com> --- arch/arm64/include/asm/spinlock.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/spinlock.h b/arch/arm64/include/asm/spinlock.h index c45b7b1..cee1287 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 -- 1.9.3
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