Re: [PATCH v2 2/5] lib/bitrev: Introduce GENERIC_BITREVERSE

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The commit's instructions for architectures to explicitly enable GENERIC_BITREVERSE will trigger Kconfig unmet dependency warnings.
--

commit dfa2feef3c11e8e7f890a24d4a12c9d0c88f4918
Author: Yury Norov <ynorov@nvidia.com>

lib/bitrev: Introduce GENERIC_BITREVERSE

This commit introduces GENERIC_BITREVERSE to allow architectures to provide
hardware-accelerated bit reversal implementations while still being able to
fall back to the generic version. It modifies Kconfig and the Makefile to
make GENERIC_BITREVERSE selectable.

> Architectures that require generic bitreverse API as a fallback should
> explicitly enable GENERIC_BITREVERSE together with HAVE_ARCH_BITREVERSE.

Will this instruction for architectures to explicitly enable GENERIC_BITREVERSE
trigger Kconfig unmet dependency warnings?

> diff --git a/lib/Kconfig b/lib/Kconfig
> index d8e7e89ae3205..a33988adfaa3e 100644
> --- a/lib/Kconfig
> +++ b/lib/Kconfig
[ ... ]
> @@ -63,6 +64,17 @@ config HAVE_ARCH_BITREVERSE
>  	  This option enables the use of hardware bit-reversal instructions on
>  	  architectures which support such operations.
>  
> +config GENERIC_BITREVERSE
> +	tristate
> +	depends on BITREVERSE

If an architecture follows the instruction in the commit message and
uses select GENERIC_BITREVERSE unconditionally, Kconfig will force it to y
even when BITREVERSE is n or m.

Even if an architecture attempts to select it conditionally via
select GENERIC_BITREVERSE if HAVE_ARCH_BITREVERSE, a warning will still occur
when BITREVERSE=m. Kconfig promotes the boolean condition HAVE_ARCH_BITREVERSE
to y, which in turn forces the tristate GENERIC_BITREVERSE to y, violating its
dependency on BITREVERSE (m).

Should architectures instead use select GENERIC_BITREVERSE if BITREVERSE to
properly inherit the dependency, or should the Kconfig dependencies be
restructured?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260506175207.110893-1-ynorov@nvidia.com?part=2