damos_wmark_metric_value's return value is 'unsigned long', so returning
-EINVAL as 'unsigned long' may turn out to be very different from the
expected one (using 2's complement) and treat as usual matric's value.
So, fix that, checking if returned value is not 0.
Link: https://lkml.kernel.org/r/20240506180238.53842-1-sj@kernel.org
Fixes: ee801b7dd7 ("mm/damon/schemes: activate schemes based on a watermarks mechanism")
Signed-off-by: Alex Rusuf <yorha.op@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
3b15f9d1c2