[PATCH v2 2/3] Maintainer Handbook: Maintainer Entry Profile

[Dan Williams]

As presented at the 2018 Linux Plumbers conference [1], the Maintainer
Entry Profile (formerly Subsystem Profile) is proposed as a way to reduce
friction between committers and maintainers and encourage conversations
amongst maintainers about common best practices. While coding-style,
submit-checklist, and submitting-drivers lay out some common expectations
there remain local customs and maintainer preferences that vary by
subsystem.

The profile contains short answers to some of the common policy questions a
contributor might have that are local to the subsystem / device-driver, or
otherwise not covered by the top-level process documents.

Overview: General introduction to how the subsystem operates
Submit Checklist Addendum: Mechanical items that gate submission staging
Key Cycle Dates:
 - Last -rc for new feature submissions: Expected lead time for submissions
 - Last -rc to merge features: Deadline for merge decisions
Coding Style Addendum: Clarifications of local style preferences
Resubmit Cadence: When to ping the maintainer
Checkpatch / Style Cleanups: Policy on pure cleanup patches

See Documentation/maintainer/maintainer-entry-profile.rst for more details,
and a follow-on example profile for the libnvdimm subsystem.

[1]: https://linuxplumbersconf.org/event/2/contributions/59/

Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Cc: Steve French <stfrench@xxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Tobin C. Harding <me@xxxxxxxx>
Cc: Olof Johansson <olof@xxxxxxxxx>
Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
 Documentation/maintainer/index.rst                 |    1 
 .../maintainer/maintainer-entry-profile.rst        |   99 ++++++++++++++++++++
 MAINTAINERS                                        |    4 +
 3 files changed, 104 insertions(+)
 create mode 100644 Documentation/maintainer/maintainer-entry-profile.rst

diff --git a/Documentation/maintainer/index.rst b/Documentation/maintainer/index.rst
index 56e2c09dfa39..d904e74e1159 100644
--- a/Documentation/maintainer/index.rst
+++ b/Documentation/maintainer/index.rst
@@ -12,4 +12,5 @@ additions to this manual.
    configure-git
    rebasing-and-merging
    pull-requests
+   maintainer-entry-profile
 
diff --git a/Documentation/maintainer/maintainer-entry-profile.rst b/Documentation/maintainer/maintainer-entry-profile.rst
new file mode 100644
index 000000000000..aaedf4d6dbf7
--- /dev/null
+++ b/Documentation/maintainer/maintainer-entry-profile.rst
@@ -0,0 +1,99 @@
+.. _maintainerentryprofile:
+
+Maintainer Entry Profile
+========================
+
+The Maintainer Entry Profile supplements the top-level process documents
+(coding-style, submitting-patches...) with subsystem/device-driver-local
+customs as well as details about the patch submission lifecycle. A
+contributor uses this document to level set their expectations and avoid
+common mistakes, maintainers may use these profiles to look across
+subsystems for opportunities to converge on common practices.
+
+
+Overview
+--------
+Provide an introduction to how the subsystem operates. While MAINTAINERS
+tells the contributor where to send patches for which files, it does not
+convey other subsystem-local infrastructure and mechanisms that aid
+development.
+Example questions to consider:
+- Are there notifications when patches are applied to the local tree, or
+  merged upstream?
+- Does the subsystem have a patchwork instance?
+- Any bots or CI infrastructure that watches the list?
+- Git branches that are pulled into -next?
+- What branch should contributors submit against?
+- Links to any other Maintainer Entry Profiles? For example a
+  device-driver may point to an entry for its parent subsystem. This makes
+  the contributor aware of obligations a maintainer may have have for
+  other maintainers in the submission chain.
+
+
+Submit Checklist Addendum
+-------------------------
+List mandatory and advisory criteria, beyond the common "submit-checklist",
+for a patch to be considered healthy enough for maintainer attention.
+For example: "pass checkpatch.pl with no errors, or warning. Pass the
+unit test detailed at $URI".
+
+
+Key Cycle Dates
+---------------
+One of the common misunderstandings of submitters is that patches can be
+sent at any time before the merge window closes and can still be
+considered for the next -rc1. The reality is that most patches need to
+be settled in soaking in linux-next in advance of the merge window
+opening. Clarify for the submitter the key dates (in terms rc release
+week) that patches might considered for merging and when patches need to
+wait for the next -rc. At a minimum:
+- Last -rc for new feature submissions:
+  New feature submissions targeting the next merge window should have
+  their first posting for consideration before this point. Patches that
+  are submitted after this point should be clear that they are targeting
+  the NEXT+1 merge window, or should come with sufficient justification
+  why they should be considered on an expedited schedule. A general
+  guideline is to set expectation with contributors that new feature
+  submissions should appear before -rc5.
+
+- Last -rc to merge features: Deadline for merge decisions
+  Indicate to contributors the point at which an as yet un-applied patch
+  set will need to wait for the NEXT+1 merge window. Of course there is no
+  obligation to ever except any given patchset, but if the review has not
+  concluded by this point the expectation the contributor should wait and
+  resubmit for the following merge window.
+
+Optional:
+- First -rc at which the development baseline branch, listed in the
+  overview section, should be considered ready for new submissions.
+
+
+Coding Style Addendum
+---------------------
+While the top-level "coding-style" document covers most style
+considerations there are still discrepancies and local preferences
+across subsystems. If a submitter should be aware of incremental / local
+style guidelines like x-mas tree variable declarations, indentation
+for multi line statements, function definition style, etc., list them
+here.
+
+
+Review Cadence
+--------------
+One of the largest sources of contributor angst is how soon to ping
+after a patchset has been posted without receiving any feedback. In
+addition to specifying how long to wait before a resubmission this
+section can also indicate a preferred style of update like, resend the
+full series, or privately send a reminder email. This section might also
+list how review works for this code area and methods to get feedback
+that are not directly from the maintainer.
+
+
+Style Cleanup Patches
+---------------------
+For subsystems with long standing code bases it is reasonable to decline
+to accept pure coding-style fixup patches. This is where you can let
+contributors know "Standalone style-cleanups are welcome",
+"Style-cleanups to existing code only welcome with other feature
+changes", or âStandalone style-cleanups to existing code are not
+welcome".
diff --git a/MAINTAINERS b/MAINTAINERS
index 3f171339df53..e5d111a86e61 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -98,6 +98,10 @@ Descriptions of section entries:
 	   Obsolete:	Old code. Something tagged obsolete generally means
 			it has been replaced by a better system and you
 			should be using that.
+	P: Subsystem Profile document for more details submitting
+	   patches to the given subsystem. This is either an in-tree file,
+	   or a URI. See Documentation/maintainer/maintainer-entry-profile.rst
+	   for details.
 	F: Files and directories with wildcard patterns.
 	   A trailing slash includes all files and subdirectory files.
 	   F:	drivers/net/	all files in and below drivers/net