02 Nov, 2017

1 commit

  • 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
    Reviewed-by: Philippe Ombredanne
    Reviewed-by: Thomas Gleixner
    Signed-off-by: Greg Kroah-Hartman

    Greg Kroah-Hartman
     

17 Feb, 2016

1 commit

  • This patch add a generic, lockless dst cache implementation.
    The need for lock is avoided updating the dst cache fields
    only in per cpu scope, and requiring that the cache manipulation
    functions are invoked with the local bh disabled.

    The refresh_ts and reset_ts fields are used to ensure the cache
    consistency in case of cuncurrent cache update (dst_cache_set*) and
    reset operation (dst_cache_reset).

    Consider the following scenario:

    CPU1: CPU2:



    dst_cache_reset()
    dst_cache_set()

    The dst entry set passed to dst_cache_set() should not be used
    for later dst cache lookup, because it's obtained using old
    configuration values.

    Since the refresh_ts is updated only on dst_cache lookup, the
    cached value in the above scenario will be discarded on the next
    lookup.

    Signed-off-by: Paolo Abeni
    Suggested-and-acked-by: Hannes Frederic Sowa
    Signed-off-by: David S. Miller

    Paolo Abeni