Re: [PATCH 2/3] Revert "lib: Revert use of fallthrough pseudo-keyword in lib/"

From: Nathan Chancellor
Date: Mon Nov 16 2020 - 22:02:21 EST

On Sun, Nov 15, 2020 at 08:35:31PM -0800, Nick Desaulniers wrote:
> This reverts commit 6a9dc5fd6170 ("lib: Revert use of fallthrough
> pseudo-keyword in lib/")
>
> Now that we can build arch/powerpc/boot/ free of -Wimplicit-fallthrough,
> re-enable these fixes for lib/.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/236
> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>

Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Tested-by: Nathan Chancellor <natechancellor@xxxxxxxxx>

> ---
> lib/asn1_decoder.c | 4 ++--
> lib/assoc_array.c | 2 +-
> lib/bootconfig.c | 4 ++--
> lib/cmdline.c | 10 +++++-----
> lib/dim/net_dim.c | 2 +-
> lib/dim/rdma_dim.c | 4 ++--
> lib/glob.c | 2 +-
> lib/siphash.c | 36 ++++++++++++++++++------------------
> lib/ts_fsm.c | 2 +-
> lib/vsprintf.c | 14 +++++++-------
> lib/xz/xz_dec_lzma2.c | 4 ++--
> lib/xz/xz_dec_stream.c | 16 ++++++++--------
> lib/zstd/bitstream.h | 10 +++++-----
> lib/zstd/compress.c | 2 +-
> lib/zstd/decompress.c | 12 ++++++------
> lib/zstd/huf_compress.c | 4 ++--
> 16 files changed, 64 insertions(+), 64 deletions(-)
>
> diff --git a/lib/asn1_decoder.c b/lib/asn1_decoder.c
> index 58f72b25f8e9..13da529e2e72 100644
> --- a/lib/asn1_decoder.c
> +++ b/lib/asn1_decoder.c
> @@ -381,7 +381,7 @@ int asn1_ber_decoder(const struct asn1_decoder *decoder,
> case ASN1_OP_END_SET_ACT:
> if (unlikely(!(flags & FLAG_MATCHED)))
> goto tag_mismatch;
> - /* fall through */
> + fallthrough;
>
> case ASN1_OP_END_SEQ:
> case ASN1_OP_END_SET_OF:
> @@ -448,7 +448,7 @@ int asn1_ber_decoder(const struct asn1_decoder *decoder,
> pc += asn1_op_lengths[op];
> goto next_op;
> }
> - /* fall through */
> + fallthrough;
>
> case ASN1_OP_ACT:
> ret = actions[machine[pc + 1]](context, hdr, tag, data + tdp, len);
> diff --git a/lib/assoc_array.c b/lib/assoc_array.c
> index 6f4bcf524554..04c98799c3ba 100644
> --- a/lib/assoc_array.c
> +++ b/lib/assoc_array.c
> @@ -1113,7 +1113,7 @@ struct assoc_array_edit *assoc_array_delete(struct assoc_array *array,
> index_key))
> goto found_leaf;
> }
> - /* fall through */
> + fallthrough;
> case assoc_array_walk_tree_empty:
> case assoc_array_walk_found_wrong_shortcut:
> default:
> diff --git a/lib/bootconfig.c b/lib/bootconfig.c
> index 649ed44f199c..9f8c70a98fcf 100644
> --- a/lib/bootconfig.c
> +++ b/lib/bootconfig.c
> @@ -827,7 +827,7 @@ int __init xbc_init(char *buf, const char **emsg, int *epos)
> q - 2);
> break;
> }
> - /* fall through */
> + fallthrough;
> case '=':
> ret = xbc_parse_kv(&p, q, c);
> break;
> @@ -836,7 +836,7 @@ int __init xbc_init(char *buf, const char **emsg, int *epos)
> break;
> case '#':
> q = skip_comment(q);
> - /* fall through */
> + fallthrough;
> case ';':
> case '\n':
> ret = xbc_parse_key(&p, q);
> diff --git a/lib/cmdline.c b/lib/cmdline.c
> index 9e186234edc0..46f2cb4ce6d1 100644
> --- a/lib/cmdline.c
> +++ b/lib/cmdline.c
> @@ -144,23 +144,23 @@ unsigned long long memparse(const char *ptr, char **retptr)
> case 'E':
> case 'e':
> ret <<= 10;
> - /* fall through */
> + fallthrough;
> case 'P':
> case 'p':
> ret <<= 10;
> - /* fall through */
> + fallthrough;
> case 'T':
> case 't':
> ret <<= 10;
> - /* fall through */
> + fallthrough;
> case 'G':
> case 'g':
> ret <<= 10;
> - /* fall through */
> + fallthrough;
> case 'M':
> case 'm':
> ret <<= 10;
> - /* fall through */
> + fallthrough;
> case 'K':
> case 'k':
> ret <<= 10;
> diff --git a/lib/dim/net_dim.c b/lib/dim/net_dim.c
> index a4db51c21266..06811d866775 100644
> --- a/lib/dim/net_dim.c
> +++ b/lib/dim/net_dim.c
> @@ -233,7 +233,7 @@ void net_dim(struct dim *dim, struct dim_sample end_sample)
> schedule_work(&dim->work);
> break;
> }
> - /* fall through */
> + fallthrough;
> case DIM_START_MEASURE:
> dim_update_sample(end_sample.event_ctr, end_sample.pkt_ctr,
> end_sample.byte_ctr, &dim->start_sample);
> diff --git a/lib/dim/rdma_dim.c b/lib/dim/rdma_dim.c
> index f7e26c7b4749..15462d54758d 100644
> --- a/lib/dim/rdma_dim.c
> +++ b/lib/dim/rdma_dim.c
> @@ -59,7 +59,7 @@ static bool rdma_dim_decision(struct dim_stats *curr_stats, struct dim *dim)
> break;
> case DIM_STATS_WORSE:
> dim_turn(dim);
> - /* fall through */
> + fallthrough;
> case DIM_STATS_BETTER:
> step_res = rdma_dim_step(dim);
> if (step_res == DIM_ON_EDGE)
> @@ -94,7 +94,7 @@ void rdma_dim(struct dim *dim, u64 completions)
> schedule_work(&dim->work);
> break;
> }
> - /* fall through */
> + fallthrough;
> case DIM_START_MEASURE:
> dim->state = DIM_MEASURE_IN_PROGRESS;
> dim_update_sample_with_comps(curr_sample->event_ctr, 0, 0,
> diff --git a/lib/glob.c b/lib/glob.c
> index 52e3ed7e4a9b..85ecbda45cd8 100644
> --- a/lib/glob.c
> +++ b/lib/glob.c
> @@ -102,7 +102,7 @@ bool __pure glob_match(char const *pat, char const *str)
> break;
> case '\\':
> d = *pat++;
> - /* fall through */
> + fallthrough;
> default: /* Literal character */
> literal:
> if (c == d) {
> diff --git a/lib/siphash.c b/lib/siphash.c
> index c47bb6ff2149..a90112ee72a1 100644
> --- a/lib/siphash.c
> +++ b/lib/siphash.c
> @@ -68,11 +68,11 @@ u64 __siphash_aligned(const void *data, size_t len, const siphash_key_t *key)
> bytemask_from_count(left)));
> #else
> switch (left) {
> - case 7: b |= ((u64)end[6]) << 48; /* fall through */
> - case 6: b |= ((u64)end[5]) << 40; /* fall through */
> - case 5: b |= ((u64)end[4]) << 32; /* fall through */
> + case 7: b |= ((u64)end[6]) << 48; fallthrough;
> + case 6: b |= ((u64)end[5]) << 40; fallthrough;
> + case 5: b |= ((u64)end[4]) << 32; fallthrough;
> case 4: b |= le32_to_cpup(data); break;
> - case 3: b |= ((u64)end[2]) << 16; /* fall through */
> + case 3: b |= ((u64)end[2]) << 16; fallthrough;
> case 2: b |= le16_to_cpup(data); break;
> case 1: b |= end[0];
> }
> @@ -101,11 +101,11 @@ u64 __siphash_unaligned(const void *data, size_t len, const siphash_key_t *key)
> bytemask_from_count(left)));
> #else
> switch (left) {
> - case 7: b |= ((u64)end[6]) << 48; /* fall through */
> - case 6: b |= ((u64)end[5]) << 40; /* fall through */
> - case 5: b |= ((u64)end[4]) << 32; /* fall through */
> + case 7: b |= ((u64)end[6]) << 48; fallthrough;
> + case 6: b |= ((u64)end[5]) << 40; fallthrough;
> + case 5: b |= ((u64)end[4]) << 32; fallthrough;
> case 4: b |= get_unaligned_le32(end); break;
> - case 3: b |= ((u64)end[2]) << 16; /* fall through */
> + case 3: b |= ((u64)end[2]) << 16; fallthrough;
> case 2: b |= get_unaligned_le16(end); break;
> case 1: b |= end[0];
> }
> @@ -268,11 +268,11 @@ u32 __hsiphash_aligned(const void *data, size_t len, const hsiphash_key_t *key)
> bytemask_from_count(left)));
> #else
> switch (left) {
> - case 7: b |= ((u64)end[6]) << 48; /* fall through */
> - case 6: b |= ((u64)end[5]) << 40; /* fall through */
> - case 5: b |= ((u64)end[4]) << 32; /* fall through */
> + case 7: b |= ((u64)end[6]) << 48; fallthrough;
> + case 6: b |= ((u64)end[5]) << 40; fallthrough;
> + case 5: b |= ((u64)end[4]) << 32; fallthrough;
> case 4: b |= le32_to_cpup(data); break;
> - case 3: b |= ((u64)end[2]) << 16; /* fall through */
> + case 3: b |= ((u64)end[2]) << 16; fallthrough;
> case 2: b |= le16_to_cpup(data); break;
> case 1: b |= end[0];
> }
> @@ -301,11 +301,11 @@ u32 __hsiphash_unaligned(const void *data, size_t len,
> bytemask_from_count(left)));
> #else
> switch (left) {
> - case 7: b |= ((u64)end[6]) << 48; /* fall through */
> - case 6: b |= ((u64)end[5]) << 40; /* fall through */
> - case 5: b |= ((u64)end[4]) << 32; /* fall through */
> + case 7: b |= ((u64)end[6]) << 48; fallthrough;
> + case 6: b |= ((u64)end[5]) << 40; fallthrough;
> + case 5: b |= ((u64)end[4]) << 32; fallthrough;
> case 4: b |= get_unaligned_le32(end); break;
> - case 3: b |= ((u64)end[2]) << 16; /* fall through */
> + case 3: b |= ((u64)end[2]) << 16; fallthrough;
> case 2: b |= get_unaligned_le16(end); break;
> case 1: b |= end[0];
> }
> @@ -431,7 +431,7 @@ u32 __hsiphash_aligned(const void *data, size_t len, const hsiphash_key_t *key)
> v0 ^= m;
> }
> switch (left) {
> - case 3: b |= ((u32)end[2]) << 16; /* fall through */
> + case 3: b |= ((u32)end[2]) << 16; fallthrough;
> case 2: b |= le16_to_cpup(data); break;
> case 1: b |= end[0];
> }
> @@ -454,7 +454,7 @@ u32 __hsiphash_unaligned(const void *data, size_t len,
> v0 ^= m;
> }
> switch (left) {
> - case 3: b |= ((u32)end[2]) << 16; /* fall through */
> + case 3: b |= ((u32)end[2]) << 16; fallthrough;
> case 2: b |= get_unaligned_le16(end); break;
> case 1: b |= end[0];
> }
> diff --git a/lib/ts_fsm.c b/lib/ts_fsm.c
> index ab749ec10ab5..64fd9015ad80 100644
> --- a/lib/ts_fsm.c
> +++ b/lib/ts_fsm.c
> @@ -193,7 +193,7 @@ static unsigned int fsm_find(struct ts_config *conf, struct ts_state *state)
> TOKEN_MISMATCH();
>
> block_idx++;
> - /* fall through */
> + fallthrough;
>
> case TS_FSM_ANY:
> if (next == NULL)
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index 14c9a6af1b23..d3c5c16f391c 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -1265,7 +1265,7 @@ char *mac_address_string(char *buf, char *end, u8 *addr,
>
> case 'R':
> reversed = true;
> - /* fall through */
> + fallthrough;
>
> default:
> separator = ':';
> @@ -1682,7 +1682,7 @@ char *uuid_string(char *buf, char *end, const u8 *addr,
> switch (*(++fmt)) {
> case 'L':
> uc = true;
> - /* fall through */
> + fallthrough;
> case 'l':
> index = guid_index;
> break;
> @@ -2219,7 +2219,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
> case 'S':
> case 's':
> ptr = dereference_symbol_descriptor(ptr);
> - /* fall through */
> + fallthrough;
> case 'B':
> return symbol_string(buf, end, ptr, spec, fmt);
> case 'R':
> @@ -2450,7 +2450,7 @@ int format_decode(const char *fmt, struct printf_spec *spec)
>
> case 'x':
> spec->flags |= SMALL;
> - /* fall through */
> + fallthrough;
>
> case 'X':
> spec->base = 16;
> @@ -2468,7 +2468,7 @@ int format_decode(const char *fmt, struct printf_spec *spec)
> * utility, treat it as any other invalid or
> * unsupported format specifier.
> */
> - /* fall through */
> + fallthrough;
>
> default:
> WARN_ONCE(1, "Please remove unsupported %%%c in format string\n", *fmt);
> @@ -3411,10 +3411,10 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
> break;
> case 'i':
> base = 0;
> - /* fall through */
> + fallthrough;
> case 'd':
> is_sign = true;
> - /* fall through */
> + fallthrough;
> case 'u':
> break;
> case '%':
> diff --git a/lib/xz/xz_dec_lzma2.c b/lib/xz/xz_dec_lzma2.c
> index 65a1aad8c223..ca2603abee08 100644
> --- a/lib/xz/xz_dec_lzma2.c
> +++ b/lib/xz/xz_dec_lzma2.c
> @@ -1043,7 +1043,7 @@ XZ_EXTERN enum xz_ret xz_dec_lzma2_run(struct xz_dec_lzma2 *s,
>
> s->lzma2.sequence = SEQ_LZMA_PREPARE;
>
> - /* fall through */
> + fallthrough;
>
> case SEQ_LZMA_PREPARE:
> if (s->lzma2.compressed < RC_INIT_BYTES)
> @@ -1055,7 +1055,7 @@ XZ_EXTERN enum xz_ret xz_dec_lzma2_run(struct xz_dec_lzma2 *s,
> s->lzma2.compressed -= RC_INIT_BYTES;
> s->lzma2.sequence = SEQ_LZMA_RUN;
>
> - /* fall through */
> + fallthrough;
>
> case SEQ_LZMA_RUN:
> /*
> diff --git a/lib/xz/xz_dec_stream.c b/lib/xz/xz_dec_stream.c
> index 32ab2a08b7cb..fea86deaaa01 100644
> --- a/lib/xz/xz_dec_stream.c
> +++ b/lib/xz/xz_dec_stream.c
> @@ -583,7 +583,7 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
> if (ret != XZ_OK)
> return ret;
>
> - /* fall through */
> + fallthrough;
>
> case SEQ_BLOCK_START:
> /* We need one byte of input to continue. */
> @@ -608,7 +608,7 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
> s->temp.pos = 0;
> s->sequence = SEQ_BLOCK_HEADER;
>
> - /* fall through */
> + fallthrough;
>
> case SEQ_BLOCK_HEADER:
> if (!fill_temp(s, b))
> @@ -620,7 +620,7 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
>
> s->sequence = SEQ_BLOCK_UNCOMPRESS;
>
> - /* fall through */
> + fallthrough;
>
> case SEQ_BLOCK_UNCOMPRESS:
> ret = dec_block(s, b);
> @@ -629,7 +629,7 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
>
> s->sequence = SEQ_BLOCK_PADDING;
>
> - /* fall through */
> + fallthrough;
>
> case SEQ_BLOCK_PADDING:
> /*
> @@ -651,7 +651,7 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
>
> s->sequence = SEQ_BLOCK_CHECK;
>
> - /* fall through */
> + fallthrough;
>
> case SEQ_BLOCK_CHECK:
> if (s->check_type == XZ_CHECK_CRC32) {
> @@ -675,7 +675,7 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
>
> s->sequence = SEQ_INDEX_PADDING;
>
> - /* fall through */
> + fallthrough;
>
> case SEQ_INDEX_PADDING:
> while ((s->index.size + (b->in_pos - s->in_start))
> @@ -699,7 +699,7 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
>
> s->sequence = SEQ_INDEX_CRC32;
>
> - /* fall through */
> + fallthrough;
>
> case SEQ_INDEX_CRC32:
> ret = crc32_validate(s, b);
> @@ -709,7 +709,7 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
> s->temp.size = STREAM_HEADER_SIZE;
> s->sequence = SEQ_STREAM_FOOTER;
>
> - /* fall through */
> + fallthrough;
>
> case SEQ_STREAM_FOOTER:
> if (!fill_temp(s, b))
> diff --git a/lib/zstd/bitstream.h b/lib/zstd/bitstream.h
> index 3a49784d5c61..7c65c66e41fd 100644
> --- a/lib/zstd/bitstream.h
> +++ b/lib/zstd/bitstream.h
> @@ -259,15 +259,15 @@ ZSTD_STATIC size_t BIT_initDStream(BIT_DStream_t *bitD, const void *srcBuffer, s
> bitD->bitContainer = *(const BYTE *)(bitD->start);
> switch (srcSize) {
> case 7: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[6]) << (sizeof(bitD->bitContainer) * 8 - 16);
> - /* fall through */
> + fallthrough;
> case 6: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[5]) << (sizeof(bitD->bitContainer) * 8 - 24);
> - /* fall through */
> + fallthrough;
> case 5: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[4]) << (sizeof(bitD->bitContainer) * 8 - 32);
> - /* fall through */
> + fallthrough;
> case 4: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[3]) << 24;
> - /* fall through */
> + fallthrough;
> case 3: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[2]) << 16;
> - /* fall through */
> + fallthrough;
> case 2: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[1]) << 8;
> default:;
> }
> diff --git a/lib/zstd/compress.c b/lib/zstd/compress.c
> index 5e0b67003e55..b080264ed3ad 100644
> --- a/lib/zstd/compress.c
> +++ b/lib/zstd/compress.c
> @@ -3182,7 +3182,7 @@ static size_t ZSTD_compressStream_generic(ZSTD_CStream *zcs, void *dst, size_t *
> zcs->outBuffFlushedSize = 0;
> zcs->stage = zcss_flush; /* pass-through to flush stage */
> }
> - /* fall through */
> + fallthrough;
>
> case zcss_flush: {
> size_t const toFlush = zcs->outBuffContentSize - zcs->outBuffFlushedSize;
> diff --git a/lib/zstd/decompress.c b/lib/zstd/decompress.c
> index db6761ea4deb..66cd487a326a 100644
> --- a/lib/zstd/decompress.c
> +++ b/lib/zstd/decompress.c
> @@ -442,7 +442,7 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx *dctx, const void *src, size_t srcSize
> case set_repeat:
> if (dctx->litEntropy == 0)
> return ERROR(dictionary_corrupted);
> - /* fall through */
> + fallthrough;
> case set_compressed:
> if (srcSize < 5)
> return ERROR(corruption_detected); /* srcSize >= MIN_CBLOCK_SIZE == 3; here we need up to 5 for case 3 */
> @@ -1768,7 +1768,7 @@ size_t ZSTD_decompressContinue(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, c
> return 0;
> }
> dctx->expected = 0; /* not necessary to copy more */
> - /* fall through */
> + fallthrough;
>
> case ZSTDds_decodeFrameHeader:
> memcpy(dctx->headerBuffer + ZSTD_frameHeaderSize_prefix, src, dctx->expected);
> @@ -2309,7 +2309,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream *zds, ZSTD_outBuffer *output, ZSTD_inB
> switch (zds->stage) {
> case zdss_init:
> ZSTD_resetDStream(zds); /* transparent reset on starting decoding a new frame */
> - /* fall through */
> + fallthrough;
>
> case zdss_loadHeader: {
> size_t const hSize = ZSTD_getFrameParams(&zds->fParams, zds->headerBuffer, zds->lhSize);
> @@ -2376,7 +2376,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream *zds, ZSTD_outBuffer *output, ZSTD_inB
> }
> zds->stage = zdss_read;
> }
> - /* fall through */
> + fallthrough;
>
> case zdss_read: {
> size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds->dctx);
> @@ -2405,7 +2405,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream *zds, ZSTD_outBuffer *output, ZSTD_inB
> zds->stage = zdss_load;
> /* pass-through */
> }
> - /* fall through */
> + fallthrough;
>
> case zdss_load: {
> size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds->dctx);
> @@ -2438,7 +2438,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream *zds, ZSTD_outBuffer *output, ZSTD_inB
> /* pass-through */
> }
> }
> - /* fall through */
> + fallthrough;
>
> case zdss_flush: {
> size_t const toFlushSize = zds->outEnd - zds->outStart;
> diff --git a/lib/zstd/huf_compress.c b/lib/zstd/huf_compress.c
> index e727812d12aa..08b4ae80aed4 100644
> --- a/lib/zstd/huf_compress.c
> +++ b/lib/zstd/huf_compress.c
> @@ -556,9 +556,9 @@ size_t HUF_compress1X_usingCTable(void *dst, size_t dstSize, const void *src, si
> n = srcSize & ~3; /* join to mod 4 */
> switch (srcSize & 3) {
> case 3: HUF_encodeSymbol(&bitC, ip[n + 2], CTable); HUF_FLUSHBITS_2(&bitC);
> - /* fall through */
> + fallthrough;
> case 2: HUF_encodeSymbol(&bitC, ip[n + 1], CTable); HUF_FLUSHBITS_1(&bitC);
> - /* fall through */
> + fallthrough;
> case 1: HUF_encodeSymbol(&bitC, ip[n + 0], CTable); HUF_FLUSHBITS(&bitC);
> case 0:
> default:;
> --
> 2.29.2.299.gdc1121823c-goog
>