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* lib: Fix fall-through warnings for ClangGustavo A. R. Silva2020-11-192-0/+2
| | | | | | | | | | | | | | In preparation to enable -Wimplicit-fallthrough for Clang, fix multiple warnings by explicitly adding multiple break statements instead of letting the code fall through to the next case, and by replacing a number of /* fall through */ comments with the new pseudo-keyword macro fallthrough. Notice that Clang doesn't recognize /* Fall through */ comments as implicit fall-through markings. Link: https://github.com/KSPP/linux/issues/115 Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
* Revert "lib: Revert use of fallthrough pseudo-keyword in lib/"Nick Desaulniers2020-11-184-14/+14
| | | | | | | | | | | | | | | | 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/. Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Link: https://github.com/ClangBuiltLinux/linux/issues/236 Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
* lib: Revert use of fallthrough pseudo-keyword in lib/Gustavo A. R. Silva2020-08-244-14/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva2020-08-234-14/+14
| | | | | | | | | | Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
* lib: Prepare zstd for preboot environment, improve performanceNick Terrell2020-07-312-10/+13
| | | | | | | | | | | | | | | | | | | | | | | | These changes are necessary to get the build to work in the preboot environment, and to get reasonable performance: - Remove a double definition of the CHECK_F macro when the zstd library is amalgamated. - Switch ZSTD_copy8() to __builtin_memcpy(), because in the preboot environment on x86 gcc can't inline `memcpy()` otherwise. - Limit the gcc hack in ZSTD_wildcopy() to the broken gcc version. See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81388. ZSTD_copy8() and ZSTD_wildcopy() are in the core of the zstd hot loop. So outlining these calls to memcpy(), and having an extra branch are very detrimental to performance. Signed-off-by: Nick Terrell <terrelln@fb.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200730190841.2071656-2-nickrterrell@gmail.com
* lib/zstd/mem.h: replace __inline by inlineRasmus Villemoes2019-09-151-1/+1
| | | | | | | | | | | | | | | | | | | | Currently, compiler_types.h #defines __inline as inline (and further #defines inline to automatically attach some attributes), so this does not change functionality. It serves as preparation for removing the #define of __inline. While at it, also remove the __attribute__((unused)) - it's already included in the definition of the inline macro, and "open-coded" __attribute__(()) should be avoided. Since commit a95b37e20db9 (kbuild: get <linux/compiler_types.h> out of <linux/kconfig.h>), compiler_types.h is automatically included by all kernel C code - i.e., the definition of inline including the unused attribute is guaranteed to be in effect whenever ZSTD_STATIC is expanded. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
* treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner2019-05-211-0/+1
| | | | | | | | | | | | | | Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* lib: zstd: Mark expected switch fall-throughsGustavo A. R. Silva2019-04-084-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In preparation to enabling -Wimplicit-fallthrough, mark switch cases where we are expecting to fall through. This patch fixes the following warnings: lib/zstd/bitstream.h:261:30: warning: this statement may fall through [-Wimplicit-fallthrough=] lib/zstd/bitstream.h:262:30: warning: this statement may fall through [-Wimplicit-fallthrough=] lib/zstd/bitstream.h:263:30: warning: this statement may fall through [-Wimplicit-fallthrough=] lib/zstd/bitstream.h:264:30: warning: this statement may fall through [-Wimplicit-fallthrough=] lib/zstd/bitstream.h:265:30: warning: this statement may fall through [-Wimplicit-fallthrough=] lib/zstd/compress.c:3183:16: warning: this statement may fall through [-Wimplicit-fallthrough=] lib/zstd/decompress.c:1770:18: warning: this statement may fall through [-Wimplicit-fallthrough=] lib/zstd/decompress.c:2376:15: warning: this statement may fall through [-Wimplicit-fallthrough=] lib/zstd/decompress.c:2404:15: warning: this statement may fall through [-Wimplicit-fallthrough=] lib/zstd/decompress.c:2435:16: warning: this statement may fall through [-Wimplicit-fallthrough=] lib/zstd/huf_compress.c: In function ‘HUF_compress1X_usingCTable’: lib/zstd/huf_compress.c:535:5: warning: this statement may fall through [-Wimplicit-fallthrough=] if (sizeof((stream)->bitContainer) * 8 < HUF_TABLELOG_MAX * 4 + 7) \ ^ lib/zstd/huf_compress.c:558:54: note: in expansion of macro ‘HUF_FLUSHBITS_2’ case 3: HUF_encodeSymbol(&bitC, ip[n + 2], CTable); HUF_FLUSHBITS_2(&bitC); ^~~~~~~~~~~~~~~ lib/zstd/huf_compress.c:559:2: note: here case 2: HUF_encodeSymbol(&bitC, ip[n + 1], CTable); HUF_FLUSHBITS_1(&bitC); ^~~~ lib/zstd/huf_compress.c:531:5: warning: this statement may fall through [-Wimplicit-fallthrough=] if (sizeof((stream)->bitContainer) * 8 < HUF_TABLELOG_MAX * 2 + 7) \ ^ lib/zstd/huf_compress.c:559:54: note: in expansion of macro ‘HUF_FLUSHBITS_1’ case 2: HUF_encodeSymbol(&bitC, ip[n + 1], CTable); HUF_FLUSHBITS_1(&bitC); ^~~~~~~~~~~~~~~ lib/zstd/huf_compress.c:560:2: note: here case 1: HUF_encodeSymbol(&bitC, ip[n + 0], CTable); HUF_FLUSHBITS(&bitC); ^~~~ AR lib/zstd//built-in.a Warning level 3 was used: -Wimplicit-fallthrough=3 This patch is part of the ongoing efforts to enabling -Wimplicit-fallthrough. Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
* lib: zstd: clean up Makefile for simpler composite object handlingMasahiro Yamada2018-03-261-13/+4
| | | | | | | | | | Now, Kbuild nicely handles composite objects to avoid multiple definition. Makefiles can simply add the same objects multiple times across composite objects. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
* lib: Add zstd modulesNick Terrell2017-08-1516-0/+11847
Add zstd compression and decompression kernel modules. zstd offers a wide varity of compression speed and quality trade-offs. It can compress at speeds approaching lz4, and quality approaching lzma. zstd decompressions at speeds more than twice as fast as zlib, and decompression speed remains roughly the same across all compression levels. The code was ported from the upstream zstd source repository. The `linux/zstd.h` header was modified to match linux kernel style. The cross-platform and allocation code was stripped out. Instead zstd requires the caller to pass a preallocated workspace. The source files were clang-formatted [1] to match the Linux Kernel style as much as possible. Otherwise, the code was unmodified. We would like to avoid as much further manual modification to the source code as possible, so it will be easier to keep the kernel zstd up to date. I benchmarked zstd compression as a special character device. I ran zstd and zlib compression at several levels, as well as performing no compression, which measure the time spent copying the data to kernel space. Data is passed to the compresser 4096 B at a time. The benchmark file is located in the upstream zstd source repository under `contrib/linux-kernel/zstd_compress_test.c` [2]. 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 `silesia.tar` [3], which is 211,988,480 B large. Run the following commands for the benchmark: sudo modprobe zstd_compress_test sudo mknod zstd_compress_test c 245 0 sudo cp silesia.tar zstd_compress_test The time is reported by the time of the userland `cp`. The MB/s is computed with 1,536,217,008 B / time(buffer size, hash) which includes the time to copy from userland. The Adjusted MB/s is computed with 1,536,217,088 B / (time(buffer size, hash) - time(buffer size, none)). The memory reported is the amount of memory the compressor requests. | Method | Size (B) | Time (s) | Ratio | MB/s | Adj MB/s | Mem (MB) | |----------|----------|----------|-------|---------|----------|----------| | none | 11988480 | 0.100 | 1 | 2119.88 | - | - | | zstd -1 | 73645762 | 1.044 | 2.878 | 203.05 | 224.56 | 1.23 | | zstd -3 | 66988878 | 1.761 | 3.165 | 120.38 | 127.63 | 2.47 | | zstd -5 | 65001259 | 2.563 | 3.261 | 82.71 | 86.07 | 2.86 | | zstd -10 | 60165346 | 13.242 | 3.523 | 16.01 | 16.13 | 13.22 | | zstd -15 | 58009756 | 47.601 | 3.654 | 4.45 | 4.46 | 21.61 | | zstd -19 | 54014593 | 102.835 | 3.925 | 2.06 | 2.06 | 60.15 | | zlib -1 | 77260026 | 2.895 | 2.744 | 73.23 | 75.85 | 0.27 | | zlib -3 | 72972206 | 4.116 | 2.905 | 51.50 | 52.79 | 0.27 | | zlib -6 | 68190360 | 9.633 | 3.109 | 22.01 | 22.24 | 0.27 | | zlib -9 | 67613382 | 22.554 | 3.135 | 9.40 | 9.44 | 0.27 | I benchmarked zstd decompression using the same method on the same machine. The benchmark file is located in the upstream zstd repo under `contrib/linux-kernel/zstd_decompress_test.c` [4]. The memory reported is the amount of memory required to decompress data compressed with the given compression level. If you know the maximum size of your input, you can reduce the memory usage of decompression irrespective of the compression level. | Method | Time (s) | MB/s | Adjusted MB/s | Memory (MB) | |----------|----------|---------|---------------|-------------| | none | 0.025 | 8479.54 | - | - | | zstd -1 | 0.358 | 592.15 | 636.60 | 0.84 | | zstd -3 | 0.396 | 535.32 | 571.40 | 1.46 | | zstd -5 | 0.396 | 535.32 | 571.40 | 1.46 | | zstd -10 | 0.374 | 566.81 | 607.42 | 2.51 | | zstd -15 | 0.379 | 559.34 | 598.84 | 4.61 | | zstd -19 | 0.412 | 514.54 | 547.77 | 8.80 | | zlib -1 | 0.940 | 225.52 | 231.68 | 0.04 | | zlib -3 | 0.883 | 240.08 | 247.07 | 0.04 | | zlib -6 | 0.844 | 251.17 | 258.84 | 0.04 | | zlib -9 | 0.837 | 253.27 | 287.64 | 0.04 | Tested in userland using the test-suite in the zstd repo under `contrib/linux-kernel/test/UserlandTest.cpp` [5] by mocking the kernel functions. Fuzz tested using libfuzzer [6] with the fuzz harnesses under `contrib/linux-kernel/test/{RoundTripCrash.c,DecompressCrash.c}` [7] [8] with ASAN, UBSAN, and MSAN. Additionaly, it was tested while testing the BtrFS and SquashFS patches coming next. [1] https://clang.llvm.org/docs/ClangFormat.html [2] https://github.com/facebook/zstd/blob/dev/contrib/linux-kernel/zstd_compress_test.c [3] http://sun.aei.polsl.pl/~sdeor/index.php?page=silesia [4] https://github.com/facebook/zstd/blob/dev/contrib/linux-kernel/zstd_decompress_test.c [5] https://github.com/facebook/zstd/blob/dev/contrib/linux-kernel/test/UserlandTest.cpp [6] http://llvm.org/docs/LibFuzzer.html [7] https://github.com/facebook/zstd/blob/dev/contrib/linux-kernel/test/RoundTripCrash.c [8] https://github.com/facebook/zstd/blob/dev/contrib/linux-kernel/test/DecompressCrash.c zstd source repository: https://github.com/facebook/zstd Signed-off-by: Nick Terrell <terrelln@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
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