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>

23 files changed, 51 insertions, 51 deletions

diff --git a/arch/alpha/include/asm/atomic.h b/arch/alpha/include/asm/atomic.h
index e8c9560..572b228 100644
--- a/arch/alpha/include/asm/atomic.h
+++ b/arch/alpha/include/asm/atomic.h
@@ -17,11 +17,11 @@
 #define ATOMIC_INIT(i)		{ (i) }
 #define ATOMIC64_INIT(i)	{ (i) }
 
-#define atomic_read(v)		ACCESS_ONCE((v)->counter)
-#define atomic64_read(v)	ACCESS_ONCE((v)->counter)
+#define atomic_read(v)		READ_ONCE((v)->counter)
+#define atomic64_read(v)	READ_ONCE((v)->counter)
 
-#define atomic_set(v,i)		((v)->counter = (i))
-#define atomic64_set(v,i)	((v)->counter = (i))
+#define atomic_set(v,i)		WRITE_ONCE((v)->counter, (i))
+#define atomic64_set(v,i)	WRITE_ONCE((v)->counter, (i))
 
 /*
  * To get proper branch prediction for the main line, we must branch
diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h
index c3ecda0..7730d30 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);
 }
 
diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h
index fe3ef39..2bf80af 100644
--- a/arch/arm/include/asm/atomic.h
+++ b/arch/arm/include/asm/atomic.h
@@ -27,8 +27,8 @@
  * strex/ldrex monitor on some implementations. The reason we can use it for
  * atomic_set() is the clrex or dummy strex done on every exception return.
  */
-#define atomic_read(v)	ACCESS_ONCE((v)->counter)
-#define atomic_set(v,i)	(((v)->counter) = (i))
+#define atomic_read(v)	READ_ONCE((v)->counter)
+#define atomic_set(v,i)	WRITE_ONCE(((v)->counter), (i))
 
 #if __LINUX_ARM_ARCH__ >= 6
 
diff --git a/arch/arm64/include/asm/atomic.h b/arch/arm64/include/asm/atomic.h
index 35a6778..1e247ac 100644
--- a/arch/arm64/include/asm/atomic.h
+++ b/arch/arm64/include/asm/atomic.h
@@ -54,7 +54,7 @@
 #define ATOMIC_INIT(i)	{ (i) }
 
 #define atomic_read(v)			READ_ONCE((v)->counter)
-#define atomic_set(v, i)		(((v)->counter) = (i))
+#define atomic_set(v, i)		WRITE_ONCE(((v)->counter), (i))
 #define atomic_xchg(v, new)		xchg(&((v)->counter), (new))
 #define atomic_cmpxchg(v, old, new)	cmpxchg(&((v)->counter), (old), (new))
 
diff --git a/arch/avr32/include/asm/atomic.h b/arch/avr32/include/asm/atomic.h
index 97c9bdf..d74fd8c 100644
--- a/arch/avr32/include/asm/atomic.h
+++ b/arch/avr32/include/asm/atomic.h
@@ -19,8 +19,8 @@
 
 #define ATOMIC_INIT(i)  { (i) }
 
-#define atomic_read(v)		ACCESS_ONCE((v)->counter)
-#define atomic_set(v, i)	(((v)->counter) = i)
+#define atomic_read(v)		READ_ONCE((v)->counter)
+#define atomic_set(v, i)	WRITE_ONCE(((v)->counter), (i))
 
 #define ATOMIC_OP_RETURN(op, asm_op, asm_con)				\
 static inline int __atomic_##op##_return(int i, atomic_t *v)		\
diff --git a/arch/frv/include/asm/atomic.h b/arch/frv/include/asm/atomic.h
index 0da689d..64f02d4 100644
--- a/arch/frv/include/asm/atomic.h
+++ b/arch/frv/include/asm/atomic.h
@@ -32,8 +32,8 @@
  */
 
 #define ATOMIC_INIT(i)		{ (i) }
-#define atomic_read(v)		ACCESS_ONCE((v)->counter)
-#define atomic_set(v, i)	(((v)->counter) = (i))
+#define atomic_read(v)		READ_ONCE((v)->counter)
+#define atomic_set(v, i)	WRITE_ONCE(((v)->counter), (i))
 
 static inline int atomic_inc_return(atomic_t *v)
 {
diff --git a/arch/h8300/include/asm/atomic.h b/arch/h8300/include/asm/atomic.h
index 702ee53..4435a44 100644
--- a/arch/h8300/include/asm/atomic.h
+++ b/arch/h8300/include/asm/atomic.h
@@ -11,8 +11,8 @@
 
 #define ATOMIC_INIT(i)	{ (i) }
 
-#define atomic_read(v)		ACCESS_ONCE((v)->counter)
-#define atomic_set(v, i)	(((v)->counter) = i)
+#define atomic_read(v)		READ_ONCE((v)->counter)
+#define atomic_set(v, i)	WRITE_ONCE(((v)->counter), (i))
 
 #include <linux/kernel.h>
 
diff --git a/arch/hexagon/include/asm/atomic.h b/arch/hexagon/include/asm/atomic.h
index 811d61f..55696c4 100644
--- a/arch/hexagon/include/asm/atomic.h
+++ b/arch/hexagon/include/asm/atomic.h
@@ -48,7 +48,7 @@ static inline void atomic_set(atomic_t *v, int new)
  *
  * Assumes all word reads on our architecture are atomic.
  */
-#define atomic_read(v)		((v)->counter)
+#define atomic_read(v)		READ_ONCE((v)->counter)
 
 /**
  * atomic_xchg - atomic
diff --git a/arch/ia64/include/asm/atomic.h b/arch/ia64/include/asm/atomic.h
index be4beeb..8dfb5f6 100644
--- a/arch/ia64/include/asm/atomic.h
+++ b/arch/ia64/include/asm/atomic.h
@@ -21,11 +21,11 @@
 #define ATOMIC_INIT(i)		{ (i) }
 #define ATOMIC64_INIT(i)	{ (i) }
 
-#define atomic_read(v)		ACCESS_ONCE((v)->counter)
-#define atomic64_read(v)	ACCESS_ONCE((v)->counter)
+#define atomic_read(v)		READ_ONCE((v)->counter)
+#define atomic64_read(v)	READ_ONCE((v)->counter)
 
-#define atomic_set(v,i)		(((v)->counter) = (i))
-#define atomic64_set(v,i)	(((v)->counter) = (i))
+#define atomic_set(v,i)		WRITE_ONCE(((v)->counter), (i))
+#define atomic64_set(v,i)	WRITE_ONCE(((v)->counter), (i))
 
 #define ATOMIC_OP(op, c_op)						\
 static __inline__ int							\
diff --git a/arch/m32r/include/asm/atomic.h b/arch/m32r/include/asm/atomic.h
index 025e2a1..ea35160 100644
--- a/arch/m32r/include/asm/atomic.h
+++ b/arch/m32r/include/asm/atomic.h
@@ -28,7 +28,7 @@
  *
  * 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
@@ -37,7 +37,7 @@
  *
  * 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))
 
 #ifdef CONFIG_CHIP_M32700_TS1
 #define __ATOMIC_CLOBBER	, "r4"
diff --git a/arch/m68k/include/asm/atomic.h b/arch/m68k/include/asm/atomic.h
index 039fac1..4858178 100644
--- a/arch/m68k/include/asm/atomic.h
+++ b/arch/m68k/include/asm/atomic.h
@@ -17,8 +17,8 @@
 
 #define ATOMIC_INIT(i)	{ (i) }
 
-#define atomic_read(v)		ACCESS_ONCE((v)->counter)
-#define atomic_set(v, i)	(((v)->counter) = i)
+#define atomic_read(v)		READ_ONCE((v)->counter)
+#define atomic_set(v, i)	WRITE_ONCE(((v)->counter), (i))
 
 /*
  * The ColdFire parts cannot do some immediate to memory operations,
diff --git a/arch/metag/include/asm/atomic_lnkget.h b/arch/metag/include/asm/atomic_lnkget.h
index 21c4c26..a625818 100644
--- a/arch/metag/include/asm/atomic_lnkget.h
+++ b/arch/metag/include/asm/atomic_lnkget.h
@@ -3,7 +3,7 @@
 
 #define ATOMIC_INIT(i)	{ (i) }
 
-#define atomic_set(v, i)		((v)->counter = (i))
+#define atomic_set(v, i)		WRITE_ONCE((v)->counter, (i))
 
 #include <linux/compiler.h>
 
diff --git a/arch/metag/include/asm/atomic_lock1.h b/arch/metag/include/asm/atomic_lock1.h
index f8efe38..0295d9b 100644
--- a/arch/metag/include/asm/atomic_lock1.h
+++ b/arch/metag/include/asm/atomic_lock1.h
@@ -10,7 +10,7 @@
 
 static inline int atomic_read(const atomic_t *v)
 {
-	return (v)->counter;
+	return READ_ONCE((v)->counter);
 }
 
 /*
diff --git a/arch/mips/include/asm/atomic.h b/arch/mips/include/asm/atomic.h
index 4c42fd9..f82d3af 100644
--- a/arch/mips/include/asm/atomic.h
+++ b/arch/mips/include/asm/atomic.h
@@ -30,7 +30,7 @@
  *
  * 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
@@ -39,7 +39,7 @@
  *
  * 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))
 
 #define ATOMIC_OP(op, c_op, asm_op)					      \
 static __inline__ void atomic_##op(int i, atomic_t * v)			      \
@@ -315,14 +315,14 @@ static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
  * @v: pointer of type atomic64_t
  *
  */
-#define atomic64_read(v)	ACCESS_ONCE((v)->counter)
+#define atomic64_read(v)	READ_ONCE((v)->counter)
 
 /*
  * atomic64_set - set atomic variable
  * @v: pointer of type atomic64_t
  * @i: required value
  */
-#define atomic64_set(v, i)	((v)->counter = (i))
+#define atomic64_set(v, i)	WRITE_ONCE((v)->counter, (i))
 
 #define ATOMIC64_OP(op, c_op, asm_op)					      \
 static __inline__ void atomic64_##op(long i, atomic64_t * v)		      \
diff --git a/arch/mn10300/include/asm/atomic.h b/arch/mn10300/include/asm/atomic.h
index 375e591..ce318d5 100644
--- a/arch/mn10300/include/asm/atomic.h
+++ b/arch/mn10300/include/asm/atomic.h
@@ -34,7 +34,7 @@
  *
  * Atomically reads the value of @v.  Note that the guaranteed
  */
-#define atomic_read(v)	(ACCESS_ONCE((v)->counter))
+#define atomic_read(v)	READ_ONCE((v)->counter)
 
 /**
  * atomic_set - set atomic variable
@@ -43,7 +43,7 @@
  *
  * Atomically sets the value of @v to @i.  Note that the guaranteed
  */
-#define atomic_set(v, i) (((v)->counter) = (i))
+#define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
 
 #define ATOMIC_OP(op)							\
 static inline void atomic_##op(int i, atomic_t *v)			\
diff --git a/arch/parisc/include/asm/atomic.h b/arch/parisc/include/asm/atomic.h
index 2536965..1d10999 100644
--- a/arch/parisc/include/asm/atomic.h
+++ b/arch/parisc/include/asm/atomic.h
@@ -67,7 +67,7 @@ static __inline__ void atomic_set(atomic_t *v, int i)
 
 static __inline__ int atomic_read(const atomic_t *v)
 {
-	return ACCESS_ONCE((v)->counter);
+	return READ_ONCE((v)->counter);
 }
 
 /* exported interface */
diff --git a/arch/sh/include/asm/atomic.h b/arch/sh/include/asm/atomic.h
index 05b9f74..c399e1c 100644
--- a/arch/sh/include/asm/atomic.h
+++ b/arch/sh/include/asm/atomic.h
@@ -14,8 +14,8 @@
 
 #define ATOMIC_INIT(i)	{ (i) }
 
-#define atomic_read(v)		ACCESS_ONCE((v)->counter)
-#define atomic_set(v,i)		((v)->counter = (i))
+#define atomic_read(v)		READ_ONCE((v)->counter)
+#define atomic_set(v,i)		WRITE_ONCE((v)->counter, (i))
 
 #if defined(CONFIG_GUSA_RB)
 #include <asm/atomic-grb.h>
diff --git a/arch/sparc/include/asm/atomic_64.h b/arch/sparc/include/asm/atomic_64.h
index 917084a..f2fbf9e 100644
--- a/arch/sparc/include/asm/atomic_64.h
+++ b/arch/sparc/include/asm/atomic_64.h
@@ -14,11 +14,11 @@
 #define ATOMIC_INIT(i)		{ (i) }
 #define ATOMIC64_INIT(i)	{ (i) }
 
-#define atomic_read(v)		ACCESS_ONCE((v)->counter)
-#define atomic64_read(v)	ACCESS_ONCE((v)->counter)
+#define atomic_read(v)		READ_ONCE((v)->counter)
+#define atomic64_read(v)	READ_ONCE((v)->counter)
 
-#define atomic_set(v, i)	(((v)->counter) = i)
-#define atomic64_set(v, i)	(((v)->counter) = i)
+#define atomic_set(v, i)	WRITE_ONCE(((v)->counter), (i))
+#define atomic64_set(v, i)	WRITE_ONCE(((v)->counter), (i))
 
 #define ATOMIC_OP(op)							\
 void atomic_##op(int, atomic_t *);					\
diff --git a/arch/tile/include/asm/atomic.h b/arch/tile/include/asm/atomic.h
index 7097984..9fc0107 100644
--- a/arch/tile/include/asm/atomic.h
+++ b/arch/tile/include/asm/atomic.h
@@ -34,7 +34,7 @@
  */
 static inline int atomic_read(const atomic_t *v)
 {
-	return ACCESS_ONCE(v->counter);
+	return READ_ONCE(v->counter);
 }
 
 /**
diff --git a/arch/tile/include/asm/atomic_64.h b/arch/tile/include/asm/atomic_64.h
index 096a56d..51cabc2 100644
--- a/arch/tile/include/asm/atomic_64.h
+++ b/arch/tile/include/asm/atomic_64.h
@@ -24,7 +24,7 @@
 
 /* First, the 32-bit atomic ops that are "real" on our 64-bit platform. */
 
-#define atomic_set(v, i) ((v)->counter = (i))
+#define atomic_set(v, i) WRITE_ONCE((v)->counter, (i))
 
 /*
  * The smp_mb() operations throughout are to support the fact that
@@ -82,8 +82,8 @@ static inline void atomic_xor(int i, atomic_t *v)
 
 #define ATOMIC64_INIT(i)	{ (i) }
 
-#define atomic64_read(v)		((v)->counter)
-#define atomic64_set(v, i) ((v)->counter = (i))
+#define atomic64_read(v)	READ_ONCE((v)->counter)
+#define atomic64_set(v, i)	WRITE_ONCE((v)->counter, (i))
 
 static inline void atomic64_add(long i, atomic64_t *v)
 {
diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h
index fb52aa6..ae5fb83 100644
--- a/arch/x86/include/asm/atomic.h
+++ b/arch/x86/include/asm/atomic.h
@@ -24,7 +24,7 @@
  */
 static __always_inline int atomic_read(const atomic_t *v)
 {
-	return ACCESS_ONCE((v)->counter);
+	return READ_ONCE((v)->counter);
 }
 
 /**
@@ -36,7 +36,7 @@ static __always_inline int atomic_read(const atomic_t *v)
  */
 static __always_inline void atomic_set(atomic_t *v, int i)
 {
-	v->counter = i;
+	WRITE_ONCE(v->counter, i);
 }
 
 /**
diff --git a/arch/x86/include/asm/atomic64_64.h b/arch/x86/include/asm/atomic64_64.h
index 50e33ef..0373510 100644
--- a/arch/x86/include/asm/atomic64_64.h
+++ b/arch/x86/include/asm/atomic64_64.h
@@ -18,7 +18,7 @@
  */
 static inline long atomic64_read(const atomic64_t *v)
 {
-	return ACCESS_ONCE((v)->counter);
+	return READ_ONCE((v)->counter);
 }
 
 /**
@@ -30,7 +30,7 @@ static inline long atomic64_read(const atomic64_t *v)
  */
 static inline void atomic64_set(atomic64_t *v, long i)
 {
-	v->counter = i;
+	WRITE_ONCE(v->counter, i);
 }
 
 /**
diff --git a/arch/xtensa/include/asm/atomic.h b/arch/xtensa/include/asm/atomic.h
index 93795d0..fd8017c 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)							\