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authorChristian Borntraeger <borntraeger@de.ibm.com>2014-11-25 11:44:26 +0100
committerChristian Borntraeger <borntraeger@de.ibm.com>2014-12-18 09:54:40 +0100
commit488beef1440e845751365202faace2465840ea98 (patch)
treef1ef574626d0253813e9436fe7a114cf48af19a5
parentaf2e7aaed1ccf30e61af3e096ac2c7df2f2d6c2a (diff)
downloadop-kernel-dev-488beef1440e845751365202faace2465840ea98.zip
op-kernel-dev-488beef1440e845751365202faace2465840ea98.tar.gz
arm/spinlock: Replace ACCESS_ONCE with 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 <borntraeger@de.ibm.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
-rw-r--r--arch/arm/include/asm/spinlock.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm/include/asm/spinlock.h b/arch/arm/include/asm/spinlock.h
index ac4bfae..0fa4184 100644
--- a/arch/arm/include/asm/spinlock.h
+++ b/arch/arm/include/asm/spinlock.h
@@ -120,12 +120,12 @@ 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)
{
- struct __raw_tickets tickets = ACCESS_ONCE(lock->tickets);
+ struct __raw_tickets tickets = READ_ONCE(lock->tickets);
return (tickets.next - tickets.owner) > 1;
}
#define arch_spin_is_contended arch_spin_is_contended
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