Re: [PATCH v2 08/16] bitfield: Simplify __BF_FIELD_CHECK_REG()

Andy Shevchenko
2025-12-28T18:53:52Z

On Wed, Dec 17, 2025 at 10:31:55PM +0000, David Laight wrote:
> On Wed, 17 Dec 2025 10:26:18 +0000
> Jonathan Cameron <jonathan.cameron@huawei.com> wrote:
> > On Fri, 12 Dec 2025 19:37:13 +0000
> > david.laight.linux@gmail.com wrote:

...

> > > + BUILD_BUG_ON_MSG((mask) + 0U + 0UL + 0ULL > \
> > > + ~0ULL >> (64 - 8 * sizeof (reg)), \
> >
> > Trivial. sizeof(reg) is much more comment syntax in kernel code.
> (common)
>
> Hmm. sizeof is an operator not a function.
> Its argument is either a variable/expression or a bracketed type
> (I don't usually put variables in brackets).
> So 'sizeof(reg)' is nearly as bad as 'return(reg)'.

Yet, it's a style used de facto in the Linux kernel. I am with Jonathan on this.

--
With Best Regards,
Andy Shevchenko