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

[Marc Zyngier <maz@kernel.org>]

On Thu, 17 Apr 2025 18:22:29 +0100,
Andrew Lunn <andrew@lunn.ch> wrote:
> 
> On Thu, Apr 17, 2025 at 12:10:54PM +0100, Marc Zyngier wrote:
> > On Thu, 17 Apr 2025 11:47:07 +0100,
> > Luo Jie <quic_luoj@quicinc.com> wrote:
> > > 
> > > Add the helper FIELD_MODIFY() to the FIELD_XXX family of bitfield
> > > macros. It is functionally similar as xxx_replace_bits(), but adds
> > > the compile time checking to catch incorrect parameter type errors.
> > > 
> > > This series also converts the four instances of opencoded FIELD_MODIFY()
> > > that are found in the core kernel files, to instead use the new
> > > FIELD_MODIFY() macro. This is achieved with Coccinelle, by adding
> > > the script field_modify.cocci.
> > > 
> > > The changes are validated on IPQ9574 SoC which uses ARM64 architecture.
> > 
> > We already have the *_replace_bits() functions (see
> > include/linux/bitfield.h).
> > 
> > Why do we need extra helpers?
> 
> If you look at bitfield.h, the *_replace_bits() seem to be
> undocumented internal macro magic, not something you are expected to
> use. What you are expected to use in that file is however well
> documented. The macro magic also means that cross referencing tools
> don't find them.

$ git grep _replace_bits|  wc -l
1514

I think a bunch of people have found them, tooling notwithstanding.

As for the documentation, the commit message in 00b0c9b82663ac would
be advantageously promoted to full-fledged kernel-doc.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.