From 62e8a3258bda118f24ff462fe04cfbe75b8189b5 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
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) <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>
---
arch/xtensa/include/asm/atomic.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
(limited to 'arch/xtensa/include/asm/atomic.h')
diff --git a/arch/xtensa/include/asm/atomic.h b/arch/xtensa/include/asm/atomic.h
index 93795d047303..fd8017ce298a 100644
--- a/arch/xtensa/include/asm/atomic.h
+++ b/arch/xtensa/include/asm/atomic.h
@@ -47,7 +47,7 @@
*
* Atomically reads the value of @v.
*/
-#define atomic_read(v) ACCESS_ONCE((v)->counter)
+#define atomic_read(v) READ_ONCE((v)->counter)
/**
* atomic_set - set atomic variable
@@ -56,7 +56,7 @@
*
* Atomically sets the value of @v to @i.
*/
-#define atomic_set(v,i) ((v)->counter = (i))
+#define atomic_set(v,i) WRITE_ONCE((v)->counter, (i))
#if XCHAL_HAVE_S32C1I
#define ATOMIC_OP(op) \
--
cgit