From 488beef1440e845751365202faace2465840ea98 Mon Sep 17 00:00:00 2001
From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Tue, 25 Nov 2014 11:44:26 +0100
Subject: 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>
---
 arch/arm/include/asm/spinlock.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'arch')

diff --git a/arch/arm/include/asm/spinlock.h b/arch/arm/include/asm/spinlock.h
index ac4bfae26702..0fa418463f49 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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