Re: [GIT PULL] fallthrough pseudo-keyword macro conversions for 5.9-rc3

["Gustavo A. R. Silva" <gustavo@embeddedor.com>]

Hi Nathan,

On 8/24/20 14:43, Nathan Chancellor wrote:

>> Gustavo A. R. Silva (1):
>>       treewide: Use fallthrough pseudo-keyword
> 
> $ scripts/config --file arch/powerpc/configs/powernv_defconfig -e KERNEL_XZ
> 
> $ make -skj"$(nproc)" ARCH=powerpc CROSS_COMPILE=powerpc64le-linux- distclean powernv_defconfig zImage
> ...
> In file included from arch/powerpc/boot/../../../lib/decompress_unxz.c:234,
>                  from arch/powerpc/boot/decompress.c:38:
> arch/powerpc/boot/../../../lib/xz/xz_dec_stream.c: In function 'dec_main':
> arch/powerpc/boot/../../../lib/xz/xz_dec_stream.c:586:4: error: 'fallthrough' undeclared (first use in this function)
>   586 |    fallthrough;
>       |    ^~~~~~~~~~~
> arch/powerpc/boot/../../../lib/xz/xz_dec_stream.c:586:4: note: each undeclared identifier is reported only once for each function it appears in
> In file included from arch/powerpc/boot/../../../lib/decompress_unxz.c:235,
>                  from arch/powerpc/boot/decompress.c:38:
> arch/powerpc/boot/../../../lib/xz/xz_dec_lzma2.c: In function 'xz_dec_lzma2_run':
> arch/powerpc/boot/../../../lib/xz/xz_dec_lzma2.c:1046:4: error: 'fallthrough' undeclared (first use in this function)
>  1046 |    fallthrough;
>       |    ^~~~~~~~~~~
> make[2]: *** [arch/powerpc/boot/Makefile:215: arch/powerpc/boot/decompress.o] Error 1
> make[2]: Target 'arch/powerpc/boot/zImage' not remade because of errors.
> make[1]: *** [arch/powerpc/Makefile:295: zImage] Error 2
> make: *** [Makefile:335: __build_one_by_one] Error 2
> make: Target 'distclean' not remade because of errors.
> make: Target 'powernv_defconfig' not remade because of errors.
> make: Target 'zImage' not remade because of errors.
> 
> This will end up affecting distribution configurations such as Debian
> and OpenSUSE according to my testing. I am not sure what the solution
> is, the PowerPC wrapper does not set -D__KERNEL__ so I am not sure that
> compiler_attributes.h can be safely included. Adding Michael and
> linuxppc-dev to CC.
> 

Thanks for the report. I think, for now, the best solution is to
use /* fall through */ comments instead of the pseudo-keyword in
lib/

I'll send a fix for that right away.

Thanks
--
Gustavo