[PATCH v2] arch: use WRITE_ONCE/READ_ONCE in smp_store_release/smp_load_acquire
Andrey Konovalov
andreyknvl at google.com
Sun Aug 2 08:11:04 PDT 2015
Replace ACCESS_ONCE() macro in smp_store_release() and smp_load_acquire()
with WRITE_ONCE() and READ_ONCE() on x86, arm, arm64, ia64, metag, mips,
powerpc, s390, sparc and asm-generic since ACCESS_ONCE does not work
reliably on non-scalar types.
WRITE_ONCE() and READ_ONCE() were introduced in the commits 230fa253df63
("kernel: Provide READ_ONCE and ASSIGN_ONCE") and 43239cbe79fc ("kernel:
Change ASSIGN_ONCE(val, x) to WRITE_ONCE(x, val)").
Signed-off-by: Andrey Konovalov <andreyknvl at google.com>
---
Changed in v2:
- Other archs besides x86.
arch/arm/include/asm/barrier.h | 4 ++--
arch/arm64/include/asm/barrier.h | 4 ++--
arch/ia64/include/asm/barrier.h | 4 ++--
arch/metag/include/asm/barrier.h | 4 ++--
arch/mips/include/asm/barrier.h | 4 ++--
arch/powerpc/include/asm/barrier.h | 4 ++--
arch/s390/include/asm/barrier.h | 4 ++--
arch/sparc/include/asm/barrier_64.h | 4 ++--
arch/x86/include/asm/barrier.h | 8 ++++----
include/asm-generic/barrier.h | 4 ++--
10 files changed, 22 insertions(+), 22 deletions(-)
diff --git a/arch/arm/include/asm/barrier.h b/arch/arm/include/asm/barrier.h
index 6c2327e..7039357 100644
--- a/arch/arm/include/asm/barrier.h
+++ b/arch/arm/include/asm/barrier.h
@@ -67,12 +67,12 @@
do { \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
___p1; \
diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h
index 0fa47c4..ef93b20 100644
--- a/arch/arm64/include/asm/barrier.h
+++ b/arch/arm64/include/asm/barrier.h
@@ -44,12 +44,12 @@
do { \
compiletime_assert_atomic_type(*p); \
barrier(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
barrier(); \
___p1; \
diff --git a/arch/ia64/include/asm/barrier.h b/arch/ia64/include/asm/barrier.h
index 843ba43..df896a1 100644
--- a/arch/ia64/include/asm/barrier.h
+++ b/arch/ia64/include/asm/barrier.h
@@ -66,12 +66,12 @@
do { \
compiletime_assert_atomic_type(*p); \
barrier(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
barrier(); \
___p1; \
diff --git a/arch/metag/include/asm/barrier.h b/arch/metag/include/asm/barrier.h
index 5a696e5..172b7e5 100644
--- a/arch/metag/include/asm/barrier.h
+++ b/arch/metag/include/asm/barrier.h
@@ -90,12 +90,12 @@ static inline void fence(void)
do { \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
___p1; \
diff --git a/arch/mips/include/asm/barrier.h b/arch/mips/include/asm/barrier.h
index 7ecba84..752e0b8 100644
--- a/arch/mips/include/asm/barrier.h
+++ b/arch/mips/include/asm/barrier.h
@@ -133,12 +133,12 @@
do { \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
___p1; \
diff --git a/arch/powerpc/include/asm/barrier.h b/arch/powerpc/include/asm/barrier.h
index 51ccc72..0eca6ef 100644
--- a/arch/powerpc/include/asm/barrier.h
+++ b/arch/powerpc/include/asm/barrier.h
@@ -76,12 +76,12 @@
do { \
compiletime_assert_atomic_type(*p); \
smp_lwsync(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
smp_lwsync(); \
___p1; \
diff --git a/arch/s390/include/asm/barrier.h b/arch/s390/include/asm/barrier.h
index e6f8615..d48fe01 100644
--- a/arch/s390/include/asm/barrier.h
+++ b/arch/s390/include/asm/barrier.h
@@ -42,12 +42,12 @@
do { \
compiletime_assert_atomic_type(*p); \
barrier(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
barrier(); \
___p1; \
diff --git a/arch/sparc/include/asm/barrier_64.h b/arch/sparc/include/asm/barrier_64.h
index 809941e..14a9286 100644
--- a/arch/sparc/include/asm/barrier_64.h
+++ b/arch/sparc/include/asm/barrier_64.h
@@ -60,12 +60,12 @@ do { __asm__ __volatile__("ba,pt %%xcc, 1f\n\t" \
do { \
compiletime_assert_atomic_type(*p); \
barrier(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
barrier(); \
___p1; \
diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h
index e51a8f8..d2bcfbe 100644
--- a/arch/x86/include/asm/barrier.h
+++ b/arch/x86/include/asm/barrier.h
@@ -57,12 +57,12 @@
do { \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
___p1; \
@@ -74,12 +74,12 @@ do { \
do { \
compiletime_assert_atomic_type(*p); \
barrier(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
barrier(); \
___p1; \
diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h
index 55e3abc..b42afad 100644
--- a/include/asm-generic/barrier.h
+++ b/include/asm-generic/barrier.h
@@ -108,12 +108,12 @@
do { \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
- ACCESS_ONCE(*p) = (v); \
+ WRITE_ONCE(*p, v); \
} while (0)
#define smp_load_acquire(p) \
({ \
- typeof(*p) ___p1 = ACCESS_ONCE(*p); \
+ typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
smp_mb(); \
___p1; \
--
2.5.0.rc2.392.g76e840b
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