Current implementation of 'atomic64_add_unless' function (and hence 'atomic64_inc_not_zero') return incorrect value if lover 32 bits of compared 64-bit number are equal and higher 32 bits aren't. For in following example atomic64_add_unless must return '1' but it actually returns '0': --------->8--------- atomic64_t val = ATOMIC64_INIT(0x4444000000000000LL); int ret = atomic64_add_unless(&val, 1LL, 0LL) --------->8--------- This happens because we write '0' to returned variable regardless of higher 32 bits comparison result. So fix it. NOTE: this change was tested with atomic64_test. Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev at synopsys.com> --- arch/arc/include/asm/atomic.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h index 11859287c52a..e840cb1763b2 100644 --- a/arch/arc/include/asm/atomic.h +++ b/arch/arc/include/asm/atomic.h @@ -578,11 +578,11 @@ static inline int atomic64_add_unless(atomic64_t *v, long long a, long long u) __asm__ __volatile__( "1: llockd %0, [%2] \n" - " mov %1, 1 \n" " brne %L0, %L4, 2f # continue to add since v != u \n" " breq.d %H0, %H4, 3f # return since v == u \n" " mov %1, 0 \n" "2: \n" + " mov %1, 1 \n" " add.f %L0, %L0, %L3 \n" " adc %H0, %H0, %H3 \n" " scondd %0, [%2] \n" -- 2.14.4
