Re: [cocci] [PATCH v3 0/6] Add FIELD_MODIFY() helper

[Yury Norov <yury.norov@gmail.com>]

On Wed, Apr 23, 2025 at 06:44:15PM +0100, Russell King (Oracle) wrote:
> On Fri, Apr 18, 2025 at 11:08:38AM -0400, Yury Norov wrote:
> > The _replace_bits() functions return fixed-width values, and intended
> > for: "manipulating bitfields both in host- and fixed-endian", as the
> > very first line in the commit message says.
> > 
> > Those using _replace_bits() for something else abuse the API, and
> > should switch to FIELD_MODIFY().
> 
> Sorry, but please explain this statement, because it means nothing to
> me.
> 
> FIELD_MODIFY() replaces bits in host endian. _replace_bits() also
> replaces bits, but has a wider range of which encompass FIELD_MODIFY().
> 
> I see nothing that precludes using using _replace_bits() with
> bitfields.
> 
> I see nothing that would differentiate the behaviour, other than maybe
> religous ideals about C functions vs macros or upper vs lower case.

Interesting, never heard about religious ideals in C.
 
> Please explain why you think there's a difference between the two
> because I really can't see any reason not to use one over the other
> apart from asthetics.

I explained that in subtread for 4/6 in this series. Shortly it's
about compiler's ability to catch various errors, like overflows,
and (not unlikely) generated code quality.