b24413180f
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
106 lines
3.0 KiB
C
106 lines
3.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_HASH_H
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#define _LINUX_HASH_H
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/* Fast hashing routine for ints, longs and pointers.
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(C) 2002 Nadia Yvette Chambers, IBM */
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#include <asm/types.h>
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#include <linux/compiler.h>
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/*
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* The "GOLDEN_RATIO_PRIME" is used in ifs/btrfs/brtfs_inode.h and
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* fs/inode.c. It's not actually prime any more (the previous primes
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* were actively bad for hashing), but the name remains.
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*/
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#if BITS_PER_LONG == 32
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#define GOLDEN_RATIO_PRIME GOLDEN_RATIO_32
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#define hash_long(val, bits) hash_32(val, bits)
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#elif BITS_PER_LONG == 64
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#define hash_long(val, bits) hash_64(val, bits)
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#define GOLDEN_RATIO_PRIME GOLDEN_RATIO_64
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#else
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#error Wordsize not 32 or 64
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#endif
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/*
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* This hash multiplies the input by a large odd number and takes the
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* high bits. Since multiplication propagates changes to the most
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* significant end only, it is essential that the high bits of the
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* product be used for the hash value.
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*
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* Chuck Lever verified the effectiveness of this technique:
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* http://www.citi.umich.edu/techreports/reports/citi-tr-00-1.pdf
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*
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* Although a random odd number will do, it turns out that the golden
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* ratio phi = (sqrt(5)-1)/2, or its negative, has particularly nice
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* properties. (See Knuth vol 3, section 6.4, exercise 9.)
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*
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* These are the negative, (1 - phi) = phi**2 = (3 - sqrt(5))/2,
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* which is very slightly easier to multiply by and makes no
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* difference to the hash distribution.
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*/
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#define GOLDEN_RATIO_32 0x61C88647
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#define GOLDEN_RATIO_64 0x61C8864680B583EBull
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#ifdef CONFIG_HAVE_ARCH_HASH
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/* This header may use the GOLDEN_RATIO_xx constants */
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#include <asm/hash.h>
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#endif
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/*
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* The _generic versions exist only so lib/test_hash.c can compare
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* the arch-optimized versions with the generic.
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*
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* Note that if you change these, any <asm/hash.h> that aren't updated
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* to match need to have their HAVE_ARCH_* define values updated so the
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* self-test will not false-positive.
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*/
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#ifndef HAVE_ARCH__HASH_32
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#define __hash_32 __hash_32_generic
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#endif
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static inline u32 __hash_32_generic(u32 val)
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{
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return val * GOLDEN_RATIO_32;
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}
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#ifndef HAVE_ARCH_HASH_32
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#define hash_32 hash_32_generic
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#endif
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static inline u32 hash_32_generic(u32 val, unsigned int bits)
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{
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/* High bits are more random, so use them. */
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return __hash_32(val) >> (32 - bits);
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}
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#ifndef HAVE_ARCH_HASH_64
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#define hash_64 hash_64_generic
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#endif
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static __always_inline u32 hash_64_generic(u64 val, unsigned int bits)
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{
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#if BITS_PER_LONG == 64
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/* 64x64-bit multiply is efficient on all 64-bit processors */
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return val * GOLDEN_RATIO_64 >> (64 - bits);
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#else
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/* Hash 64 bits using only 32x32-bit multiply. */
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return hash_32((u32)val ^ __hash_32(val >> 32), bits);
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#endif
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}
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static inline u32 hash_ptr(const void *ptr, unsigned int bits)
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{
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return hash_long((unsigned long)ptr, bits);
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}
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/* This really should be called fold32_ptr; it does no hashing to speak of. */
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static inline u32 hash32_ptr(const void *ptr)
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{
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unsigned long val = (unsigned long)ptr;
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#if BITS_PER_LONG == 64
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val ^= (val >> 32);
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#endif
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return (u32)val;
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}
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#endif /* _LINUX_HASH_H */
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