Re: [PATCH 3/9] bitmap: Use FIELD_PREP() in expansion of FIELD_PREP_WM16()

Andy Shevchenko
2025-12-09T15:46:28Z

On Tue, Dec 09, 2025 at 10:03:07AM +0000, david.laight.linux@gmail.com wrote:

> Instead of directly expanding __BF_FIELD_CHECK() (which really ought
> not be used outside bitfield) and open-coding the generation of the
> masked value, just call FIELD_PREP() and add an extra check for
> the mask being at most 16 bits.

...

> +#define FIELD_PREP_WM16(mask, val) \
> +({ \
> + __auto_type _mask = mask; \
> + u32 _val = FIELD_PREP(_mask, val); \

> + BUILD_BUG_ON_MSG(_mask > 0xffffu, \
> + "FIELD_PREP_WM16: mask too large"); \

Can it be static_assert() instead?

> + _val | (_mask << 16); \
> +})

--
With Best Regards,
Andy Shevchenko