On Mon, Oct 17, 2022 at 06:17:59PM -0700, Andrew Morton wrote:
...
> -#define __clamp(val, lo, hi) \
> +#define __clamp(val, lo, hi) \
> __cmp(__cmp(val, lo, >), hi, <)
>
> -#define __clamp_once(val, lo, hi, unique_val, unique_lo, unique_hi) ({ \
> - typeof(val) unique_val = (val); \
> - typeof(lo) unique_lo = (lo); \
> - typeof(hi) unique_hi = (hi); \
> +#define __clamp_once(val, lo, hi, unique_val, unique_lo, unique_hi) ({ \
> + typeof(val) unique_val = (val); \
> + typeof(lo) unique_lo = (lo); \
> + typeof(hi) unique_hi = (hi); \
> __clamp(unique_val, unique_lo, unique_hi); })
>
> -#define __clamp_input_check(lo, hi) \
> - (BUILD_BUG_ON_ZERO(__builtin_choose_expr( \
> +#define __clamp_input_check(lo, hi) \
> + (BUILD_BUG_ON_ZERO(__builtin_choose_expr( \
> __is_constexpr((lo) > (hi)), (lo) > (hi), false)))
These are good...
> -#define __careful_clamp(val, lo, hi) ({ \
> - __clamp_input_check(lo, hi) + \
> - __builtin_choose_expr(__typecheck(val, lo) && __typecheck(val, hi) && \
> - __typecheck(hi, lo) && __is_constexpr(val) && \
> - __is_constexpr(lo) && __is_constexpr(hi), \
> - __clamp(val, lo, hi), \
> - __clamp_once(val, lo, hi, __UNIQUE_ID(__val), \
> +#define __careful_clamp(val, lo, hi) ({ \
> + __clamp_input_check(lo, hi) + \
> + __builtin_choose_expr(__typecheck(val, lo) && __typecheck(val, hi) &&\
> + __typecheck(hi, lo) && __is_constexpr(val) &&\
> + __is_constexpr(lo) && __is_constexpr(hi), \
> + __clamp(val, lo, hi), \
> + __clamp_once(val, lo, hi, __UNIQUE_ID(__val), \
> __UNIQUE_ID(__lo), __UNIQUE_ID(__hi))); })
...but this one becomes less readable. I think checkpatch is always a
recommendation than requirement. I would leave at least the last as is, but
formally I think the entire patch is a churn to satisfy controversial
recommendation.
--
With Best Regards,
Andy Shevchenko
