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| author | Will Deacon <will@kernel.org> | 2019-10-30 17:51:07 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-07-21 11:50:35 +0200 |
| commit | 3c9184109e78ea2371ca8fa66d7f36986a53af98 (patch) | |
| tree | ccbd407080e099d75880bc5ac4d083645a12d62c /include/asm-generic/rwonce.h | |
| parent | alpha: Override READ_ONCE() with barriered implementation (diff) | |
| download | linux-3c9184109e78ea2371ca8fa66d7f36986a53af98.tar.xz linux-3c9184109e78ea2371ca8fa66d7f36986a53af98.zip | |
asm/rwonce: Remove smp_read_barrier_depends() invocation
Alpha overrides __READ_ONCE() directly, so there's no need to use
smp_read_barrier_depends() in the core code. This also means that
__READ_ONCE() can be relied upon to provide dependency ordering.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'include/asm-generic/rwonce.h')
| -rw-r--r-- | include/asm-generic/rwonce.h | 19 |
1 files changed, 4 insertions, 15 deletions
diff --git a/include/asm-generic/rwonce.h b/include/asm-generic/rwonce.h index 04586b55a7c2..3a7f737c77bd 100644 --- a/include/asm-generic/rwonce.h +++ b/include/asm-generic/rwonce.h @@ -40,24 +40,16 @@ /* * Use __READ_ONCE() instead of READ_ONCE() if you do not require any - * atomicity or dependency ordering guarantees. Note that this may result - * in tears! + * atomicity. Note that this may result in tears! */ #ifndef __READ_ONCE #define __READ_ONCE(x) (*(const volatile __unqual_scalar_typeof(x) *)&(x)) #endif -#define __READ_ONCE_SCALAR(x) \ -({ \ - __unqual_scalar_typeof(x) __x = __READ_ONCE(x); \ - smp_read_barrier_depends(); \ - (typeof(x))__x; \ -}) - #define READ_ONCE(x) \ ({ \ compiletime_assert_rwonce_type(x); \ - __READ_ONCE_SCALAR(x); \ + __READ_ONCE(x); \ }) #define __WRITE_ONCE(x, val) \ @@ -84,12 +76,9 @@ unsigned long __read_once_word_nocheck(const void *addr) */ #define READ_ONCE_NOCHECK(x) \ ({ \ - unsigned long __x; \ - compiletime_assert(sizeof(x) == sizeof(__x), \ + compiletime_assert(sizeof(x) == sizeof(unsigned long), \ "Unsupported access size for READ_ONCE_NOCHECK()."); \ - __x = __read_once_word_nocheck(&(x)); \ - smp_read_barrier_depends(); \ - (typeof(x))__x; \ + (typeof(x))__read_once_word_nocheck(&(x)); \ }) static __no_kasan_or_inline |