Re: [PATCH] s390: fix -Wundef warning for CONFIG_KERNEL_ZSTD

[Heiko Carstens]

On Sat, Jan 07, 2023 at 01:10:23AM +0900, Masahiro Yamada wrote:
> Since commit 80b6093b55e3 ("kbuild: add -Wundef to KBUILD_CPPFLAGS
> for W=1 builds"), building with W=1 detects misuse of #(el)if.
> 
>   $ make W=1 ARCH=s390 CROSS_COMPILE=s390x-linux-gnu-
>     [snip]
>   arch/s390/boot/decompressor.c:28:7: warning: "CONFIG_KERNEL_ZSTD" is not defined, evaluates to 0 [-Wundef]
>      28 | #elif CONFIG_KERNEL_ZSTD
>         |       ^~~~~~~~~~~~~~~~~~
> 
> This issue has been hidden because arch/s390/boot/Makefile overwrites
> KBUILD_CFLAGS, dropping -Wundef.
> 
> CONFIG_KERNEL_ZSTD is a bool option. #elif defined() should be used.
> 
> The line #ifdef CONFIG_KERNEL_BZIP2 is fine, but I changed it for
> consistency.
> 
> Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
> ---
> 
>  arch/s390/boot/decompressor.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Applied, thanks!