Re: [PATCH v2] asm-generic: fix variable 'p4d' set but not used

[Arnd Bergmann]

On Wed, Aug 7, 2019 at 1:29 AM Qian Cai <cai@xxxxxx> wrote:
>
> A compiler throws a warning on an arm64 system since the
> commit 9849a5697d3d ("arch, mm: convert all architectures to use
> 5level-fixup.h"),
>
> mm/kasan/init.c: In function 'kasan_free_p4d':
> mm/kasan/init.c:344:9: warning: variable 'p4d' set but not used
> [-Wunused-but-set-variable]
>  p4d_t *p4d;
>         ^~~
>
> because p4d_none() in "5level-fixup.h" is compiled away while it is a
> static inline function in "pgtable-nopud.h". However, if converted
> p4d_none() to a static inline there, powerpc would be unhappy as it
> reads those in assembler language in
> "arch/powerpc/include/asm/book3s/64/pgtable.h", so it needs to skip
> assembly include for the static inline C function. While at it,
> converted a few similar functions to be consistent with the ones in
> "pgtable-nopud.h".
>
> Signed-off-by: Qian Cai <cai@xxxxxx>

Acked-by: Arnd Bergmann <arnd@xxxxxxxx>