[PATCH 0/7] Support for automatic checkpatch running in the kernel

From: Knut Omang
Date: Thu Nov 16 2017 - 12:02:58 EST

This patch series implements features to facilitate running checkpatch on the
entire kernel as part of automatic testing.

This is done by by adding a few small features to checkpatch and put these
features to use to implement support for a new Makefile environment variable
P={1,2} following the pattern of sparse and the C={1,2} variable. The basic
functionality + docs are in patch #1-4.

It also fixes a minor issue with "checkpatch --fix-inplace" found during testing
(patch #5).

The most important checkpatch feature added is the --ignore-cfg feature, which
takes a file argument and parses that file according to this minimal language:

# comments
line_len <n>
except checkpatch_type [files ...]
pervasive checkpatch_type1 [checkpatch_type2 ...]

With "make P=2" checkpatch is called with "--file" and "--ignore_cfg
checkpatch.cfg" which causes it to look for a file named 'checkpatch.cfg' in the
same directory as the source file. If that file exists, checkpatch will be run
with an implicit --strict and with the @ignore list expanded with content from
the configuration file. If it does not exist, make will simply silently ignore
the file.

Patches #6-7 enhances this behaviour to also scan the directories above a file
until a match for the --file parameter is found.

The idea is that the community can work to add checkpatch.cfg files to
directories, serving both as documentation and as a way for subsystem
maintainers to enforce policies and individual tastes as well as TODOs and/or
priorities, to make it easier for newcomers to contribute in this area. By
ignoring directories without such files, automation can start right away as it
is trivially possible to run errorless with P=2 for the entire kernel.

The patches includes a documentation file with some more details.

This patch set has evolved from an earlier implementation I made that was just a
wrapper script around checkpatch. That version have been used for a number of
years on a driver project I worked on where we had automatic checkin regression
testing. I extended that to also run checkpatch to avoid having to clean up
frequent unintended whitespace changes and style violations from others...

I have also tested this version on some directories I am familiar with. The
result of that work is available in two patch sets of 10 and 11 patches, but we
agreed that it would be better to post them as separate patch sets later.

Those patch sets illustrates how I picture the "flow" from just "reining in" the
checkpatch detections to actually fixing classes of checkpatch issues one by
one, while updating the checkpatch.cfg file(s) to have 0 errors or warnings at
any commit boundary.

The combined set is available here:

git://github.com/knuto/linux.git branch checkpatch

Comments and suggestions appreciated!


Knut Omang (7):
checkpatch: Implement new --ignore-cfg parameter
kbuild: Add P= command line flag to run checkpatch
checkpatch: Add a few convenience options to disable/modify features
Documentation: Add documentation for the new P= Makefile option
checkpatch: Improve --fix-inplace for TABSTOP
checkpatch: Make --ignore-cfg look recursively for the file
Documentation: Update checkpatch --ignore-cfg description

Documentation/dev-tools/index.rst | 1 +-
Documentation/dev-tools/run-checkpatch.rst | 109 ++++++++++++++++++++++-
Makefile | 20 +++-
scripts/Makefile.build | 13 +++-
scripts/checkpatch.pl | 108 +++++++++++++++++++++-
5 files changed, 249 insertions(+), 2 deletions(-)
create mode 100644 Documentation/dev-tools/run-checkpatch.rst

base-commit: bebc6082da0a9f5d47a1ea2edc099bf671058bd4
git-series 0.9.1