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authorPeter Zijlstra <peterz@infradead.org>2015-09-18 11:13:10 +0200
committerIngo Molnar <mingo@kernel.org>2015-09-23 09:54:28 +0200
commit62e8a3258bda118f24ff462fe04cfbe75b8189b5 (patch)
tree79edd4b96f8c3495435be8b148127d5738d1db63 /arch/arc/include/asm/atomic.h
parent90fe65148ea76988d8d5acbf3e578aa74129a490 (diff)
atomic, arch: Audit atomic_{read,set}()
This patch makes sure that atomic_{read,set}() are at least {READ,WRITE}_ONCE(). We already had the 'requirement' that atomic_read() should use ACCESS_ONCE(), and most archs had this, but a few were lacking. All are now converted to use READ_ONCE(). And, by a symmetry and general paranoia argument, upgrade atomic_set() to use WRITE_ONCE(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: james.hogan@imgtec.com Cc: linux-kernel@vger.kernel.org Cc: oleg@redhat.com Cc: will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/arc/include/asm/atomic.h')
-rw-r--r--arch/arc/include/asm/atomic.h8
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h
index c3ecda023e3a..7730d302cadb 100644
--- a/arch/arc/include/asm/atomic.h
+++ b/arch/arc/include/asm/atomic.h
@@ -17,11 +17,11 @@
#include <asm/barrier.h>
#include <asm/smp.h>
-#define atomic_read(v) ((v)->counter)
+#define atomic_read(v) READ_ONCE((v)->counter)
#ifdef CONFIG_ARC_HAS_LLSC
-#define atomic_set(v, i) (((v)->counter) = (i))
+#define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
#ifdef CONFIG_ARC_STAR_9000923308
@@ -107,7 +107,7 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \
#ifndef CONFIG_SMP
/* violating atomic_xxx API locking protocol in UP for optimization sake */
-#define atomic_set(v, i) (((v)->counter) = (i))
+#define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
#else
@@ -125,7 +125,7 @@ static inline void atomic_set(atomic_t *v, int i)
unsigned long flags;
atomic_ops_lock(flags);
- v->counter = i;
+ WRITE_ONCE(v->counter, i);
atomic_ops_unlock(flags);
}