[PATCH] lib: Revert use of fallthrough pseudo-keyword in lib/

From: Gustavo A. R. Silva
Date: Mon Aug 24 2020 - 16:30:26 EST

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;
| ^~~~~~~~~~~
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."

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@xxxxxxxxx>
Fixes: df561f6688fe ("treewide: Use fallthrough pseudo-keyword")
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
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 13da529e2e72..58f72b25f8e9 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;
- fallthrough;
+ /* fall through */

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;
}
- fallthrough;
+ /* fall through */

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 04c98799c3ba..6f4bcf524554 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;
}
- fallthrough;
+ /* fall through */
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 1b5de2a45b27..2c905a91d4eb 100644
--- a/lib/bootconfig.c
+++ b/lib/bootconfig.c
@@ -817,7 +817,7 @@ int __init xbc_init(char *buf, const char **emsg, int *epos)
q - 2);
break;
}
- fallthrough;
+ /* fall through */
case '=':
ret = xbc_parse_kv(&p, q, c);
break;
@@ -826,7 +826,7 @@ int __init xbc_init(char *buf, const char **emsg, int *epos)
break;
case '#':
q = skip_comment(q);
- fallthrough;
+ /* fall through */
case ';':
case '\n':
ret = xbc_parse_key(&p, q);
diff --git a/lib/cmdline.c b/lib/cmdline.c
index 55768b4f3f58..fbb9981a04a4 100644
--- a/lib/cmdline.c
+++ b/lib/cmdline.c
@@ -132,23 +132,23 @@ unsigned long long memparse(const char *ptr, char **retptr)
case 'E':
case 'e':
ret <<= 10;
- fallthrough;
+ /* fall through */
case 'P':
case 'p':
ret <<= 10;
- fallthrough;
+ /* fall through */
case 'T':
case 't':
ret <<= 10;
- fallthrough;
+ /* fall through */
case 'G':
case 'g':
ret <<= 10;
- fallthrough;
+ /* fall through */
case 'M':
case 'm':
ret <<= 10;
- fallthrough;
+ /* fall through */
case 'K':
case 'k':
ret <<= 10;
diff --git a/lib/dim/net_dim.c b/lib/dim/net_dim.c
index 06811d866775..a4db51c21266 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;
}
- fallthrough;
+ /* fall through */
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 15462d54758d..f7e26c7b4749 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);
- fallthrough;
+ /* fall through */
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;
}
- fallthrough;
+ /* fall through */
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 85ecbda45cd8..52e3ed7e4a9b 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++;
- fallthrough;
+ /* fall through */
default: /* Literal character */
literal:
if (c == d) {
diff --git a/lib/siphash.c b/lib/siphash.c
index a90112ee72a1..c47bb6ff2149 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; fallthrough;
- case 6: b |= ((u64)end[5]) << 40; fallthrough;
- case 5: b |= ((u64)end[4]) << 32; fallthrough;
+ 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 4: b |= le32_to_cpup(data); break;
- case 3: b |= ((u64)end[2]) << 16; fallthrough;
+ case 3: b |= ((u64)end[2]) << 16; /* fall through */
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; fallthrough;
- case 6: b |= ((u64)end[5]) << 40; fallthrough;
- case 5: b |= ((u64)end[4]) << 32; fallthrough;
+ 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 4: b |= get_unaligned_le32(end); break;
- case 3: b |= ((u64)end[2]) << 16; fallthrough;
+ case 3: b |= ((u64)end[2]) << 16; /* fall through */
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; fallthrough;
- case 6: b |= ((u64)end[5]) << 40; fallthrough;
- case 5: b |= ((u64)end[4]) << 32; fallthrough;
+ 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 4: b |= le32_to_cpup(data); break;
- case 3: b |= ((u64)end[2]) << 16; fallthrough;
+ case 3: b |= ((u64)end[2]) << 16; /* fall through */
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; fallthrough;
- case 6: b |= ((u64)end[5]) << 40; fallthrough;
- case 5: b |= ((u64)end[4]) << 32; fallthrough;
+ 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 4: b |= get_unaligned_le32(end); break;
- case 3: b |= ((u64)end[2]) << 16; fallthrough;
+ case 3: b |= ((u64)end[2]) << 16; /* fall through */
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; fallthrough;
+ case 3: b |= ((u32)end[2]) << 16; /* fall through */
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; fallthrough;
+ case 3: b |= ((u32)end[2]) << 16; /* fall through */
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 64fd9015ad80..ab749ec10ab5 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++;
- fallthrough;
+ /* fall through */

case TS_FSM_ANY:
if (next == NULL)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 19ebe1b257ec..afb9521ddf91 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;
- fallthrough;
+ /* fall through */

default:
separator = ':';
@@ -1682,7 +1682,7 @@ char *uuid_string(char *buf, char *end, const u8 *addr,
switch (*(++fmt)) {
case 'L':
uc = true;
- fallthrough;
+ /* fall through */
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);
- fallthrough;
+ /* fall through */
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;
- fallthrough;
+ /* fall through */

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.
*/
- fallthrough;
+ /* fall through */

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;
- fallthrough;
+ /* fall through */
case 'd':
is_sign = true;
- fallthrough;
+ /* fall through */
case 'u':
break;
case '%':
diff --git a/lib/xz/xz_dec_lzma2.c b/lib/xz/xz_dec_lzma2.c
index ca2603abee08..65a1aad8c223 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;

- fallthrough;
+ /* fall through */

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;

- fallthrough;
+ /* fall through */

case SEQ_LZMA_RUN:
/*
diff --git a/lib/xz/xz_dec_stream.c b/lib/xz/xz_dec_stream.c
index fea86deaaa01..32ab2a08b7cb 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;

- fallthrough;
+ /* fall through */

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;

- fallthrough;
+ /* fall through */

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;

- fallthrough;
+ /* fall through */

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;

- fallthrough;
+ /* fall through */

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;

- fallthrough;
+ /* fall through */

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;

- fallthrough;
+ /* fall through */

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;

- fallthrough;
+ /* fall through */

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;

- fallthrough;
+ /* fall through */

case SEQ_STREAM_FOOTER:
if (!fill_temp(s, b))
diff --git a/lib/zstd/bitstream.h b/lib/zstd/bitstream.h
index 7c65c66e41fd..3a49784d5c61 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);
- fallthrough;
+ /* fall through */
case 6: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[5]) << (sizeof(bitD->bitContainer) * 8 - 24);
- fallthrough;
+ /* fall through */
case 5: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[4]) << (sizeof(bitD->bitContainer) * 8 - 32);
- fallthrough;
+ /* fall through */
case 4: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[3]) << 24;
- fallthrough;
+ /* fall through */
case 3: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[2]) << 16;
- fallthrough;
+ /* fall through */
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 b080264ed3ad..5e0b67003e55 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 */
}
- fallthrough;
+ /* fall through */

case zcss_flush: {
size_t const toFlush = zcs->outBuffContentSize - zcs->outBuffFlushedSize;
diff --git a/lib/zstd/decompress.c b/lib/zstd/decompress.c
index 66cd487a326a..db6761ea4deb 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);
- fallthrough;
+ /* fall through */
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 */
- fallthrough;
+ /* fall through */

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 */
- fallthrough;
+ /* fall through */

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;
}
- fallthrough;
+ /* fall through */

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 */
}
- fallthrough;
+ /* fall through */

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 */
}
}
- fallthrough;
+ /* fall through */

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 08b4ae80aed4..e727812d12aa 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);
- fallthrough;
+ /* fall through */
case 2: HUF_encodeSymbol(&bitC, ip[n + 1], CTable); HUF_FLUSHBITS_1(&bitC);
- fallthrough;
+ /* fall through */
case 1: HUF_encodeSymbol(&bitC, ip[n + 0], CTable); HUF_FLUSHBITS(&bitC);
case 0:
default:;
--
2.27.0