kernel/linux.git/lib/xxhash.c, branch v6.19.11

lib/xxhash: remove more unused xxh functions

2025-11-12T18:00:17+00:00

xxh32_reset() and xxh32_copy_state() are unused, and with those gone, the xxh32_state struct is also unused. xxh64_copy_state() is also unused. Remove them all. (Also fixes a comment above the xxh64_state that referred to it as xxh32_state). Link: https://lkml.kernel.org/r/20251024205120.454508-1-linux@treblig.org Signed-off-by: Dr. David Alan Gilbert Suggested-by: Christoph Hellwig Reviewed-by: Kuan-Wei Chiu Reviewed-by: Christoph Hellwig Signed-off-by: Andrew Morton

lib/xxhash: remove unused functions

2025-08-02T19:01:37+00:00

xxh32_digest() and xxh32_update() were added in 2017 in the original xxhash commit, but have remained unused. Remove them. Link: https://lkml.kernel.org/r/20250716133245.243363-1-linux@treblig.org Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Christoph Hellwig Cc: Dave Gilbert Cc: Nick Terrell Signed-off-by: Andrew Morton

move asm/unaligned.h to linux/unaligned.h

2024-10-02T21:23:23+00:00

asm/unaligned.h is always an include of asm-generic/unaligned.h; might as well move that thing to linux/unaligned.h and include that - there's nothing arch-specific in that header. auto-generated by the following: for i in `git grep -l -w asm/unaligned.h`; do sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i done for i in `git grep -l -w asm-generic/unaligned.h`; do sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i done git mv include/asm-generic/unaligned.h include/linux/unaligned.h git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h

lib/: replace HTTP links with HTTPS ones

2020-08-12T17:58:00+00:00

Rationale: Reduces attack surface on kernel devs opening the links for MITM as HTTPS traffic is much harder to manipulate. Signed-off-by: Alexander A. Klimov Signed-off-by: Andrew Morton Acked-by: Coly Li [crc64.c] Link: http://lkml.kernel.org/r/20200726112154.16510-1-grandmaster@al2klimov.de Signed-off-by: Linus Torvalds

lib: Add xxhash module

2017-08-15T16:02:07+00:00

Adds xxhash kernel module with xxh32 and xxh64 hashes. xxhash is an extremely fast non-cryptographic hash algorithm for checksumming. The zstd compression and decompression modules added in the next patch require xxhash. I extracted it out from zstd since it is useful on its own. I copied the code from the upstream XXHash source repository and translated it into kernel style. I ran benchmarks and tests in the kernel and tests in userland. I benchmarked xxhash as a special character device. I ran in four modes, no-op, xxh32, xxh64, and crc32. The no-op mode simply copies the data to kernel space and ignores it. The xxh32, xxh64, and crc32 modes compute hashes on the copied data. I also ran it with four different buffer sizes. The benchmark file is located in the upstream zstd source repository under `contrib/linux-kernel/xxhash_test.c` [1]. I ran the benchmarks on a Ubuntu 14.04 VM with 2 cores and 4 GiB of RAM. The VM is running on a MacBook Pro with a 3.1 GHz Intel Core i7 processor, 16 GB of RAM, and a SSD. I benchmarked using the file `filesystem.squashfs` from `ubuntu-16.10-desktop-amd64.iso`, which is 1,536,217,088 B large. Run the following commands for the benchmark: modprobe xxhash_test mknod xxhash_test c 245 0 time cp filesystem.squashfs xxhash_test The time is reported by the time of the userland `cp`. The GB/s is computed with 1,536,217,008 B / time(buffer size, hash) which includes the time to copy from userland. The Normalized GB/s is computed with 1,536,217,088 B / (time(buffer size, hash) - time(buffer size, none)). | Buffer Size (B) | Hash | Time (s) | GB/s | Adjusted GB/s | |-----------------|-------|----------|------|---------------| | 1024 | none | 0.408 | 3.77 | - | | 1024 | xxh32 | 0.649 | 2.37 | 6.37 | | 1024 | xxh64 | 0.542 | 2.83 | 11.46 | | 1024 | crc32 | 1.290 | 1.19 | 1.74 | | 4096 | none | 0.380 | 4.04 | - | | 4096 | xxh32 | 0.645 | 2.38 | 5.79 | | 4096 | xxh64 | 0.500 | 3.07 | 12.80 | | 4096 | crc32 | 1.168 | 1.32 | 1.95 | | 8192 | none | 0.351 | 4.38 | - | | 8192 | xxh32 | 0.614 | 2.50 | 5.84 | | 8192 | xxh64 | 0.464 | 3.31 | 13.60 | | 8192 | crc32 | 1.163 | 1.32 | 1.89 | | 16384 | none | 0.346 | 4.43 | - | | 16384 | xxh32 | 0.590 | 2.60 | 6.30 | | 16384 | xxh64 | 0.466 | 3.30 | 12.80 | | 16384 | crc32 | 1.183 | 1.30 | 1.84 | Tested in userland using the test-suite in the zstd repo under `contrib/linux-kernel/test/XXHashUserlandTest.cpp` [2] by mocking the kernel functions. A line in each branch of every function in `xxhash.c` was commented out to ensure that the test-suite fails. Additionally tested while testing zstd and with SMHasher [3]. [1] https://phabricator.intern.facebook.com/P57526246 [2] https://github.com/facebook/zstd/blob/dev/contrib/linux-kernel/test/XXHashUserlandTest.cpp [3] https://github.com/aappleby/smhasher zstd source repository: https://github.com/facebook/zstd XXHash source repository: https://github.com/cyan4973/xxhash Signed-off-by: Nick Terrell Signed-off-by: Chris Mason