Messages in this thread Patch in this message | | | From | Junru Shen <> | Subject | [PATCH] atomic: Put the fetching of the old value into the loop when doing atomic CAS | Date | Thu, 24 Feb 2022 16:24:38 +0800 |
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Put the acquisition of the expected value inside the loop to prevent an infinite loop when it does not match.
Signed-off-by: Junru Shen <hhusjrsjr@gmail.com> --- arch/x86/include/asm/atomic64_64.h | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/atomic64_64.h b/arch/x86/include/asm/atomic64_64.h index 7886d0578..3df04c44c 100644 --- a/arch/x86/include/asm/atomic64_64.h +++ b/arch/x86/include/asm/atomic64_64.h @@ -207,9 +207,10 @@ static inline void arch_atomic64_and(s64 i, atomic64_t *v) static inline s64 arch_atomic64_fetch_and(s64 i, atomic64_t *v) { - s64 val = arch_atomic64_read(v); + s64 val; do { + val = arch_atomic64_read(v); } while (!arch_atomic64_try_cmpxchg(v, &val, val & i)); return val; } @@ -225,9 +226,10 @@ static inline void arch_atomic64_or(s64 i, atomic64_t *v) static inline s64 arch_atomic64_fetch_or(s64 i, atomic64_t *v) { - s64 val = arch_atomic64_read(v); + s64 val; do { + val = arch_atomic64_read(v); } while (!arch_atomic64_try_cmpxchg(v, &val, val | i)); return val; } @@ -243,9 +245,10 @@ static inline void arch_atomic64_xor(s64 i, atomic64_t *v) static inline s64 arch_atomic64_fetch_xor(s64 i, atomic64_t *v) { - s64 val = arch_atomic64_read(v); + s64 val; do { + val = arch_atomic64_read(v); } while (!arch_atomic64_try_cmpxchg(v, &val, val ^ i)); return val; } -- 2.30.2
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