From: Pranith Kumar Date: Tue, 23 Sep 2014 14:29:50 +0000 (-0400) Subject: locking,arch: Use ACCESS_ONCE() instead of cast to volatile in atomic_read() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=2291059c852706c6f5ffb400366042b7625066cd;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git 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 Acked-by: Jesper Nilsson Acked-by: Hans-Christian Egtvedt Acked-by: Max Filippov Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds 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 --- diff --git a/arch/alpha/include/asm/atomic.h b/arch/alpha/include/asm/atomic.h index 6fbb53a13049..8f8eafbedd7c 100644 --- 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 832f1cdfcd6a..e22c11970b7b 100644 --- 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 b83c325e587f..7047051ded40 100644 --- 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 83e980a4e483..2d07ce1c5327 100644 --- 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 0033f9dfea24..279766a70664 100644 --- 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 f6c3a1690101..102190a61d65 100644 --- 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 42919a831c6c..0bf03501fe5c 100644 --- 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 3946b2c8d971..31bb74adba08 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) (*(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 663d4ba2462c..e85f047fb072 100644 --- 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 f3ee721fe61d..6dd6bfc607e9 100644 --- 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 219750bb4ae7..226f8ca993f6 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 (*(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 f57b8a6743b3..05b9f74ce2d5 100644 --- 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 7b024f02a7ce..765c1776ec9f 100644 --- 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 7e4ca1e73cd9..4082749913ce 100644 --- 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 bf20c817ed34..5e5cd123fdfb 100644 --- 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 46e9052bbd28..f8d273e18516 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 (*(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 626676660b80..00b7d46b35b8 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) (*(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 56d4d36e1531..1973ad2b13f4 100644 --- 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 /**