From 62e8a3258bda118f24ff462fe04cfbe75b8189b5 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 18 Sep 2015 11:13:10 +0200 Subject: 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) Cc: Andrew Morton Cc: Dmitry Vyukov Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner 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 --- arch/arc/include/asm/atomic.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'arch/arc') 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 #include -#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); } -- cgit v1.2.3-59-g8ed1b