Re: [PATCH 01/10 net-next v2] ipv6: convert CONFIG_IPV6 to built-in only and clean up Kconfigs

[Krzysztof Kozlowski <krzk@kernel.org>]

On 10/03/2026 16:34, Fernando Fernandez Mancera wrote:
> Maintaining a modular IPv6 stack offers image size and memory savings
> for specific setups, this benefit is outweighed by the architectural
> burden it imposes on the subsystems on implementation and maintenance.
> Therefore, drop it.
> 
> Change CONFIG_IPV6 from tristate to bool. Remove all Kconfig
> dependencies across the tree that explicitly checked for IPV6=m. In
> addition, remove MODULE_DESCRIPTION(), MODULE_ALIAS(), MODULE_AUTHOR()
> and MODULE_LICENSE().
> 
> This is also replacing module_init() by device_initcall(). It is not
> possible to use fs_initcall() as IPv4 does because that creates a race
> condition on IPv6 addrconf.
> 
> Finally, modify the default configs from CONFIG_IPV6=m to CONFIG_IPV6=y
> except for m68k as according to the bloat-o-meter the image is
> increasing by 330KB~ and that isn't acceptable. Instead, disable IPv6 on
> this architecture by default. This is aligned with m68k RAM requirements
> and recommendations [1].
> 
> [1] http://www.linux-m68k.org/faq/ram.html
> 
> Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
> ---
> v2: updated m68k default configuration to CONFIG_IPV6=n and used
> device_initcall() instead fs_initcall() to avoid a race condition.

Don't know exavtly netdev policy about merging cover letters, but if the
cover letter does not end up merged (e.g. with b4), then please move
other bloatometer stats here. Although the best if cover letter is
simply merged.

> ---
>  arch/arm64/configs/defconfig                |  2 +-

Acked-by: Krzysztof Kozlowski <krzk@kernel.org> # arm64

>  arch/m68k/configs/amiga_defconfig           | 45 +-------------------
>  arch/m68k/configs/apollo_defconfig          | 46 +-------------------
>  arch/m68k/configs/atari_defconfig           | 45 +-------------------
>  arch/m68k/configs/bvme6000_defconfig        | 45 +-------------------
>  arch/m68k/configs/hp300_defconfig           | 47 +--------------------
>  arch/m68k/configs/mac_defconfig             | 45 +-------------------
>  arch/m68k/configs/multi_defconfig           | 45 +-------------------
>  arch/m68k/configs/mvme147_defconfig         | 45 +-------------------
>  arch/m68k/configs/mvme16x_defconfig         | 45 +-------------------
>  arch/m68k/configs/q40_defconfig             | 45 +-------------------
>  arch/m68k/configs/sun3_defconfig            | 45 +-------------------
>  arch/m68k/configs/sun3x_defconfig           | 45 +-------------------

Thanks Fernando for addressing the comments. Great job!

Best regards,
Krzysztof