path: root/lib
diff options
authorNick Terrell <>2021-11-15 19:08:19 -0800
committerNick Terrell <>2021-11-18 13:12:26 -0800
commitae8d67b2117f1ec6c8170d6e1af8ded17392bd2c (patch)
tree009387a5ef8e5120f82cd8a6dd5340ce0dd86f79 /lib
parentfa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf (diff)
lib: zstd: Fix unused variable warning
The variable `litLengthSum` is only used by an `assert()`, so when asserts are disabled the compiler doesn't see any usage and warns. This issue is already fixed upstream by PR #2838 [0]. It was reported by the Kernel test robot in [1]. Another approach would be to change zstd's disabled `assert()` definition to use the argument in a disabled branch, instead of ignoring the argument. I've avoided this approach because there are some small changes necessary to get zstd to build, and I would want to thoroughly re-test for performance, since that is slightly changing the code in every function in zstd. It seems like a trivial change, but some functions are pretty sensitive to small changes. However, I think it is a valid approach that I would like to see upstream take, so I've opened Issue #2868 to attempt this upstream. Lastly, I've chosen not to use __maybe_unused because all code in lib/zstd/ must eventually be upstreamed. Upstream zstd can't use __maybe_unused because it isn't portable across all compilers. [0] [1] [2] Link: Link: Reported-by: kernel test robot <> Signed-off-by: Nick Terrell <>
Diffstat (limited to 'lib')
1 files changed, 2 insertions, 0 deletions
diff --git a/lib/zstd/compress/zstd_compress_superblock.c b/lib/zstd/compress/zstd_compress_superblock.c
index ee03e0aedb03..b0610b255653 100644
--- a/lib/zstd/compress/zstd_compress_superblock.c
+++ b/lib/zstd/compress/zstd_compress_superblock.c
@@ -411,6 +411,8 @@ static size_t ZSTD_seqDecompressedSize(seqStore_t const* seqStore, const seqDef*
const seqDef* sp = sstart;
size_t matchLengthSum = 0;
size_t litLengthSum = 0;
+ /* Only used by assert(), suppress unused variable warnings in production. */
+ (void)litLengthSum;
while (send-sp > 0) {
ZSTD_sequenceLength const seqLen = ZSTD_getSequenceLength(seqStore, sp);
litLengthSum += seqLen.litLength;