lib: Revert use of fallthrough pseudo-keyword in lib/
authorGustavo A. R. Silva <gustavoars@kernel.org>
Mon, 24 Aug 2020 20:36:14 +0000 (15:36 -0500)
committerLinus Torvalds <torvalds@linux-foundation.org>
Mon, 24 Aug 2020 21:17:44 +0000 (14:17 -0700)
commit6a9dc5fd6170d0a41c8a14eb19e63d94bea5705a
tree7d33b5d3fa40ab47f2a5d711fc034a008cc9e83f
parent9907ab371426da8b3cffa6cc3e4ae54829559207
lib: Revert use of fallthrough pseudo-keyword in lib/

The following build error for powerpc64 was reported by Nathan Chancellor:

  "$ 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;
         |    ^~~~~~~~~~~

   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."

In order to avoid these sort of problems, it seems that the best
solution is to use /* fall through */ comments instead of the
fallthrough pseudo-keyword macro in lib/, for now.

Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Fixes: df561f6688fe ("treewide: Use fallthrough pseudo-keyword")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-and-tested-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
16 files changed:
lib/asn1_decoder.c
lib/assoc_array.c
lib/bootconfig.c
lib/cmdline.c
lib/dim/net_dim.c
lib/dim/rdma_dim.c
lib/glob.c
lib/siphash.c
lib/ts_fsm.c
lib/vsprintf.c
lib/xz/xz_dec_lzma2.c
lib/xz/xz_dec_stream.c
lib/zstd/bitstream.h
lib/zstd/compress.c
lib/zstd/decompress.c
lib/zstd/huf_compress.c