1. 26 Oct, 2018 1 commit
  2. 02 Nov, 2017 1 commit
    • Greg Kroah-Hartman's avatar
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman authored
      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: default avatarKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: default avatarPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  3. 07 Oct, 2017 1 commit
  4. 14 Jan, 2017 1 commit
  5. 10 Nov, 2015 2 commits
  6. 11 Dec, 2013 1 commit
  7. 23 Aug, 2013 1 commit
    • Mike Snitzer's avatar
      math64: New separate div64_u64_rem helper · eb18cba7
      Mike Snitzer authored
      Commit f7926850 ("math64: New
      div64_u64_rem helper") implemented div64_u64 in terms of div64_u64_rem.
      But div64_u64_rem was removed because it slowed down div64_u64 (and
      there were no other users of div64_u64_rem).
      
      Device Mapper's I/O statistics support has a need for div64_u64_rem;
      reintroduce this helper as a separate method that doesn't slow down
      div64_u64, especially on 32-bit systems.
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      Cc: Stanislaw Gruszka <sgruszka@redhat.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Mikulas Patocka <mpatocka@redhat.com>
      Signed-off-by: Alasdair Kergon's avatarAlasdair G Kergon <agk@redhat.com>
      eb18cba7
  8. 12 Jun, 2013 1 commit
  9. 30 Apr, 2013 1 commit
  10. 13 Mar, 2013 1 commit
    • Frederic Weisbecker's avatar
      math64: New div64_u64_rem helper · f7926850
      Frederic Weisbecker authored
      Provide an extended version of div64_u64() that
      also returns the remainder of the division.
      
      We are going to need this to refine the cputime
      scaling code.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Stanislaw Gruszka <sgruszka@redhat.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      f7926850
  11. 15 Mar, 2012 1 commit
  12. 26 Oct, 2010 1 commit
  13. 12 Jun, 2008 2 commits
    • Jeremy Fitzhardinge's avatar
      add an inlined version of iter_div_u64_rem · d5e181f7
      Jeremy Fitzhardinge authored
      iter_div_u64_rem is used in the x86-64 vdso, which cannot call other
      kernel code.  For this case, provide the always_inlined version,
      __iter_div_u64_rem.
      Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      d5e181f7
    • Jeremy Fitzhardinge's avatar
      common implementation of iterative div/mod · f595ec96
      Jeremy Fitzhardinge authored
      We have a few instances of the open-coded iterative div/mod loop, used
      when we don't expcet the dividend to be much bigger than the divisor.
      Unfortunately modern gcc's have the tendency to strength "reduce" this
      into a full mod operation, which isn't necessarily any faster, and
      even if it were, doesn't exist if gcc implements it in libgcc.
      
      The workaround is to put a dummy asm statement in the loop to prevent
      gcc from performing the transformation.
      
      This patch creates a single implementation of this loop, and uses it
      to replace the open-coded versions I know about.
      Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: john stultz <johnstul@us.ibm.com>
      Cc: Segher Boessenkool <segher@kernel.crashing.org>
      Cc: Christian Kujau <lists@nerdbynature.de>
      Cc: Robert Hancock <hancockr@shaw.ca>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      f595ec96
  14. 01 May, 2008 2 commits
    • Roman Zippel's avatar
      rename div64_64 to div64_u64 · 6f6d6a1a
      Roman Zippel authored
      Rename div64_64 to div64_u64 to make it consistent with the other divide
      functions, so it clearly includes the type of the divide.  Move its definition
      to math64.h as currently no architecture overrides the generic implementation.
       They can still override it of course, but the duplicated declarations are
      avoided.
      Signed-off-by: default avatarRoman Zippel <zippel@linux-m68k.org>
      Cc: Avi Kivity <avi@qumranet.com>
      Cc: Russell King <rmk@arm.linux.org.uk>
      Cc: Geert Uytterhoeven <geert@linux-m68k.org>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Jeff Dike <jdike@addtoit.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: Patrick McHardy <kaber@trash.net>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6f6d6a1a
    • Roman Zippel's avatar
      introduce explicit signed/unsigned 64bit divide · 2418f4f2
      Roman Zippel authored
      The current do_div doesn't explicitly say that it's unsigned and the signed
      counterpart is missing, which is e.g.  needed when dealing with time values.
      
      This introduces 64bit signed/unsigned divide functions which also attempts to
      cleanup the somewhat awkward calling API, which often requires the use of
      temporary variables for the dividend.  To avoid the need for temporary
      variables everywhere for the remainder, each divide variant also provides a
      version which doesn't return the remainder.
      
      Each architecture can now provide optimized versions of these function,
      otherwise generic fallback implementations will be used.
      
      As an example I provided an alternative for the current x86 divide, which
      avoids the asm casts and using an union allows gcc to generate better code.
      It also avoids the upper divde in a few more cases, where the result is known
      (i.e.  upper quotient is zero).
      Signed-off-by: default avatarRoman Zippel <zippel@linux-m68k.org>
      Cc: john stultz <johnstul@us.ibm.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2418f4f2