locking,arch: Use ACCESS_ONCE() instead of cast to volatile in atomic_read()

Use the much more reader friendly ACCESS_ONCE() instead of the cast to volatile.
This is purely a stylistic change.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Link: http://lkml.kernel.org/r/1411482607-20948-1-git-send-email-bobby.prani@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/alpha/include/asm/atomic.h b/arch/alpha/include/asm/atomic.h
index 6fbb53a..8f8eafb 100644 (file)
--- a/arch/alpha/include/asm/atomic.h
+++ b/arch/alpha/include/asm/atomic.h
@@ -17,8 +17,8 @@
 #define ATOMIC_INIT(i)         { (i) }
 #define ATOMIC64_INIT(i)       { (i) }
 
-#define atomic_read(v)         (*(volatile int *)&(v)->counter)
-#define atomic64_read(v)       (*(volatile long *)&(v)->counter)
+#define atomic_read(v)         ACCESS_ONCE((v)->counter)
+#define atomic64_read(v)       ACCESS_ONCE((v)->counter)
 
 #define atomic_set(v,i)                ((v)->counter = (i))
 #define atomic64_set(v,i)      ((v)->counter = (i))

diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h
index 832f1cd..e22c119 100644 (file)
--- a/arch/arm/include/asm/atomic.h
+++ b/arch/arm/include/asm/atomic.h
@@ -27,7 +27,7 @@
  * 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) (*(volatile int *)&(v)->counter)
+#define atomic_read(v) ACCESS_ONCE((v)->counter)
 #define atomic_set(v,i)        (((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 b83c325..7047051 100644 (file)
--- a/arch/arm64/include/asm/atomic.h
+++ b/arch/arm64/include/asm/atomic.h
@@ -35,7 +35,7 @@
  * 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) (*(volatile int *)&(v)->counter)
+#define atomic_read(v) ACCESS_ONCE((v)->counter)
 #define atomic_set(v,i)        (((v)->counter) = (i))
 
 /*
@@ -139,7 +139,7 @@ static inline int __atomic_add_unless(atomic_t *v, int a, int u)
  */
 #define ATOMIC64_INIT(i) { (i) }
 
-#define atomic64_read(v)       (*(volatile long *)&(v)->counter)
+#define atomic64_read(v)       ACCESS_ONCE((v)->counter)
 #define atomic64_set(v,i)      (((v)->counter) = (i))
 
 #define ATOMIC64_OP(op, asm_op)                                                \

diff --git a/arch/avr32/include/asm/atomic.h b/arch/avr32/include/asm/atomic.h
index 83e980a..2d07ce1 100644 (file)
--- a/arch/avr32/include/asm/atomic.h
+++ b/arch/avr32/include/asm/atomic.h
@@ -19,7 +19,7 @@
 
 #define ATOMIC_INIT(i)  { (i) }
 
-#define atomic_read(v)         (*(volatile int *)&(v)->counter)
+#define atomic_read(v)         ACCESS_ONCE((v)->counter)
 #define atomic_set(v, i)       (((v)->counter) = i)
 
 #define ATOMIC_OP_RETURN(op, asm_op, asm_con)                          \

diff --git a/arch/cris/include/asm/atomic.h b/arch/cris/include/asm/atomic.h
index 0033f9d..279766a 100644 (file)
--- a/arch/cris/include/asm/atomic.h
+++ b/arch/cris/include/asm/atomic.h
@@ -17,7 +17,7 @@
 
 #define ATOMIC_INIT(i)  { (i) }
 
-#define atomic_read(v) (*(volatile int *)&(v)->counter)
+#define atomic_read(v) ACCESS_ONCE((v)->counter)
 #define atomic_set(v,i) (((v)->counter) = (i))
 
 /* These should be written in asm but we do it in C for now. */

diff --git a/arch/frv/include/asm/atomic.h b/arch/frv/include/asm/atomic.h
index f6c3a16..102190a 100644 (file)
--- a/arch/frv/include/asm/atomic.h
+++ b/arch/frv/include/asm/atomic.h
@@ -31,7 +31,7 @@
  */
 
 #define ATOMIC_INIT(i)         { (i) }
-#define atomic_read(v)         (*(volatile int *)&(v)->counter)
+#define atomic_read(v)         ACCESS_ONCE((v)->counter)
 #define atomic_set(v, i)       (((v)->counter) = (i))
 
 #ifndef CONFIG_FRV_OUTOFLINE_ATOMIC_OPS

diff --git a/arch/ia64/include/asm/atomic.h b/arch/ia64/include/asm/atomic.h
index 42919a8..0bf0350 100644 (file)
--- a/arch/ia64/include/asm/atomic.h
+++ b/arch/ia64/include/asm/atomic.h
@@ -21,8 +21,8 @@
 #define ATOMIC_INIT(i)         { (i) }
 #define ATOMIC64_INIT(i)       { (i) }
 
-#define atomic_read(v)         (*(volatile int *)&(v)->counter)
-#define atomic64_read(v)       (*(volatile long *)&(v)->counter)
+#define atomic_read(v)         ACCESS_ONCE((v)->counter)
+#define atomic64_read(v)       ACCESS_ONCE((v)->counter)
 
 #define atomic_set(v,i)                (((v)->counter) = (i))
 #define atomic64_set(v,i)      (((v)->counter) = (i))

diff --git a/arch/m32r/include/asm/atomic.h b/arch/m32r/include/asm/atomic.h
index 3946b2c..31bb74a 100644 (file)
--- 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) (*(volatile int *)&(v)->counter)
+#define atomic_read(v) ACCESS_ONCE((v)->counter)
 
 /**
  * atomic_set - set atomic variable

diff --git a/arch/m68k/include/asm/atomic.h b/arch/m68k/include/asm/atomic.h
index 663d4ba..e85f047 100644 (file)
--- a/arch/m68k/include/asm/atomic.h
+++ b/arch/m68k/include/asm/atomic.h
@@ -17,7 +17,7 @@
 
 #define ATOMIC_INIT(i) { (i) }
 
-#define atomic_read(v)         (*(volatile int *)&(v)->counter)
+#define atomic_read(v)         ACCESS_ONCE((v)->counter)
 #define atomic_set(v, i)       (((v)->counter) = i)
 
 /*

diff --git a/arch/mips/include/asm/atomic.h b/arch/mips/include/asm/atomic.h
index f3ee721..6dd6bfc 100644 (file)
--- a/arch/mips/include/asm/atomic.h
+++ b/arch/mips/include/asm/atomic.h
@@ -29,7 +29,7 @@
  *
  * Atomically reads the value of @v.
  */
-#define atomic_read(v)         (*(volatile int *)&(v)->counter)
+#define atomic_read(v)         ACCESS_ONCE((v)->counter)
 
 /*
  * atomic_set - set atomic variable
@@ -306,7 +306,7 @@ static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
  * @v: pointer of type atomic64_t
  *
  */
-#define atomic64_read(v)       (*(volatile long *)&(v)->counter)
+#define atomic64_read(v)       ACCESS_ONCE((v)->counter)
 
 /*
  * atomic64_set - set atomic variable

diff --git a/arch/parisc/include/asm/atomic.h b/arch/parisc/include/asm/atomic.h
index 219750b..226f8ca 100644 (file)
--- 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 (*(volatile int *)&(v)->counter);
+       return ACCESS_ONCE((v)->counter);
 }
 
 /* exported interface */
@@ -204,7 +204,7 @@ atomic64_set(atomic64_t *v, s64 i)
 static __inline__ s64
 atomic64_read(const atomic64_t *v)
 {
-       return (*(volatile long *)&(v)->counter);
+       return ACCESS_ONCE((v)->counter);
 }
 
 #define atomic64_inc(v)                (atomic64_add(   1,(v)))

diff --git a/arch/sh/include/asm/atomic.h b/arch/sh/include/asm/atomic.h
index f57b8a6..05b9f74 100644 (file)
--- a/arch/sh/include/asm/atomic.h
+++ b/arch/sh/include/asm/atomic.h
@@ -14,7 +14,7 @@
 
 #define ATOMIC_INIT(i) { (i) }
 
-#define atomic_read(v)         (*(volatile int *)&(v)->counter)
+#define atomic_read(v)         ACCESS_ONCE((v)->counter)
 #define atomic_set(v,i)                ((v)->counter = (i))
 
 #if defined(CONFIG_GUSA_RB)

diff --git a/arch/sparc/include/asm/atomic_32.h b/arch/sparc/include/asm/atomic_32.h
index 7b024f0..765c177 100644 (file)
--- a/arch/sparc/include/asm/atomic_32.h
+++ b/arch/sparc/include/asm/atomic_32.h
@@ -26,7 +26,7 @@ int atomic_cmpxchg(atomic_t *, int, int);
 int __atomic_add_unless(atomic_t *, int, int);
 void atomic_set(atomic_t *, int);
 
-#define atomic_read(v)          (*(volatile int *)&(v)->counter)
+#define atomic_read(v)          ACCESS_ONCE((v)->counter)
 
 #define atomic_add(i, v)       ((void)atomic_add_return( (int)(i), (v)))
 #define atomic_sub(i, v)       ((void)atomic_add_return(-(int)(i), (v)))

diff --git a/arch/sparc/include/asm/atomic_64.h b/arch/sparc/include/asm/atomic_64.h
index 7e4ca1e..4082749 100644 (file)
--- a/arch/sparc/include/asm/atomic_64.h
+++ b/arch/sparc/include/asm/atomic_64.h
@@ -14,8 +14,8 @@
 #define ATOMIC_INIT(i)         { (i) }
 #define ATOMIC64_INIT(i)       { (i) }
 
-#define atomic_read(v)         (*(volatile int *)&(v)->counter)
-#define atomic64_read(v)       (*(volatile long *)&(v)->counter)
+#define atomic_read(v)         ACCESS_ONCE((v)->counter)
+#define atomic64_read(v)       ACCESS_ONCE((v)->counter)
 
 #define atomic_set(v, i)       (((v)->counter) = i)
 #define atomic64_set(v, i)     (((v)->counter) = i)

diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h
index bf20c81..5e5cd12 100644 (file)
--- a/arch/x86/include/asm/atomic.h
+++ b/arch/x86/include/asm/atomic.h
@@ -24,7 +24,7 @@
  */
 static inline int atomic_read(const atomic_t *v)
 {
-       return (*(volatile int *)&(v)->counter);
+       return ACCESS_ONCE((v)->counter);
 }
 
 /**

diff --git a/arch/x86/include/asm/atomic64_64.h b/arch/x86/include/asm/atomic64_64.h
index 46e9052..f8d273e 100644 (file)
--- 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 (*(volatile long *)&(v)->counter);
+       return ACCESS_ONCE((v)->counter);
 }
 
 /**

diff --git a/arch/xtensa/include/asm/atomic.h b/arch/xtensa/include/asm/atomic.h
index 6266766..00b7d46 100644 (file)
--- 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)         (*(volatile int *)&(v)->counter)
+#define atomic_read(v)         ACCESS_ONCE((v)->counter)
 
 /**
  * atomic_set - set atomic variable

diff --git a/include/asm-generic/atomic.h b/include/asm-generic/atomic.h
index 56d4d36..1973ad2 100644 (file)
--- a/include/asm-generic/atomic.h
+++ b/include/asm-generic/atomic.h
@@ -126,7 +126,7 @@ ATOMIC_OP(or, |)
  * Atomically reads the value of @v.
  */
 #ifndef atomic_read
-#define atomic_read(v) (*(volatile int *)&(v)->counter)
+#define atomic_read(v) ACCESS_ONCE((v)->counter)
 #endif
 
 /**