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atomic, arch: Audit atomic_{read,set}()

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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>
This commit is contained in:
Peter Zijlstra
2015-09-18 11:13:10 +02:00
committed by Ingo Molnar
parent 90fe65148e
commit 62e8a3258b
24 changed files with 53 additions and 53 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
arch/arc/include/asm/atomic.h
View File

@@ -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);
}