+If you are a subsystem or branch maintainer, sometimes you need to slightly
+modify patches you receive in order to merge them, because the code is not
+exactly the same in your tree and the submitters'. If you stick strictly to
+rule (c), you should ask the submitter to rediff, but this is a totally
+counter-productive waste of time and energy. Rule (b) allows you to adjust
+the code, but then it is very impolite to change one submitter's code and
+make him endorse your bugs. To solve this problem, it is recommended that
+you add a line between the last Signed-off-by header and yours, indicating
+the nature of your changes. While there is nothing mandatory about this, it
+seems like prepending the description with your mail and/or name, all
+enclosed in square brackets, is noticeable enough to make it obvious that
+you are responsible for last-minute changes. Example :
+
+ Signed-off-by: Random J Developer <random@developer.example.org>
+ [lucky@maintainer.example.org: struct foo moved from foo.c to foo.h]
+ Signed-off-by: Lucky K Maintainer <lucky@maintainer.example.org>
+
+This practise is particularly helpful if you maintain a stable branch and
+want at the same time to credit the author, track changes, merge the fix,
+and protect the submitter from complaints. Note that under no circumstances
+can you change the author's identity (the From header), as it is the one
+which appears in the changelog.
+
+Special note to back-porters: It seems to be a common and useful practise
+to insert an indication of the origin of a patch at the top of the commit
+message (just after the subject line) to facilitate tracking. For instance,
+here's what we see in 2.6-stable :
+
+ Date: Tue May 13 19:10:30 2008 +0000
+
+ SCSI: libiscsi regression in 2.6.25: fix nop timer handling
+
+ commit 4cf1043593db6a337f10e006c23c69e5fc93e722 upstream
+
+And here's what appears in 2.4 :
+
+ Date: Tue May 13 22:12:27 2008 +0200
+
+ wireless, airo: waitbusy() won't delay
+
+ [backport of 2.6 commit b7acbdfbd1f277c1eb23f344f899cfa4cd0bf36a]
+
+Whatever the format, this information provides a valuable help to people
+tracking your trees, and to people trying to trouble-shoot bugs in your
+tree.
+
+
+13) When to use Acked-by: and Cc:
+
+The Signed-off-by: tag indicates that the signer was involved in the
+development of the patch, or that he/she was in the patch's delivery path.
+
+If a person was not directly involved in the preparation or handling of a
+patch but wishes to signify and record their approval of it then they can
+arrange to have an Acked-by: line added to the patch's changelog.
+
+Acked-by: is often used by the maintainer of the affected code when that
+maintainer neither contributed to nor forwarded the patch.
+
+Acked-by: is not as formal as Signed-off-by:. It is a record that the acker
+has at least reviewed the patch and has indicated acceptance. Hence patch
+mergers will sometimes manually convert an acker's "yep, looks good to me"
+into an Acked-by:.
+
+Acked-by: does not necessarily indicate acknowledgement of the entire patch.
+For example, if a patch affects multiple subsystems and has an Acked-by: from
+one subsystem maintainer then this usually indicates acknowledgement of just
+the part which affects that maintainer's code. Judgement should be used here.
+When in doubt people should refer to the original discussion in the mailing
+list archives.
+
+If a person has had the opportunity to comment on a patch, but has not
+provided such comments, you may optionally add a "Cc:" tag to the patch.
+This is the only tag which might be added without an explicit action by the
+person it names. This tag documents that potentially interested parties
+have been included in the discussion
+
+
+14) Using Reported-by:, Tested-by: and Reviewed-by:
+
+If this patch fixes a problem reported by somebody else, consider adding a
+Reported-by: tag to credit the reporter for their contribution. Please
+note that this tag should not be added without the reporter's permission,
+especially if the problem was not reported in a public forum. That said,
+if we diligently credit our bug reporters, they will, hopefully, be
+inspired to help us again in the future.
+
+A Tested-by: tag indicates that the patch has been successfully tested (in
+some environment) by the person named. This tag informs maintainers that
+some testing has been performed, provides a means to locate testers for
+future patches, and ensures credit for the testers.
+
+Reviewed-by:, instead, indicates that the patch has been reviewed and found
+acceptable according to the Reviewer's Statement:
+
+ Reviewer's statement of oversight
+
+ By offering my Reviewed-by: tag, I state that:
+
+ (a) I have carried out a technical review of this patch to
+ evaluate its appropriateness and readiness for inclusion into
+ the mainline kernel.
+
+ (b) Any problems, concerns, or questions relating to the patch
+ have been communicated back to the submitter. I am satisfied
+ with the submitter's response to my comments.
+
+ (c) While there may be things that could be improved with this
+ submission, I believe that it is, at this time, (1) a
+ worthwhile modification to the kernel, and (2) free of known
+ issues which would argue against its inclusion.
+
+ (d) While I have reviewed the patch and believe it to be sound, I
+ do not (unless explicitly stated elsewhere) make any
+ warranties or guarantees that it will achieve its stated
+ purpose or function properly in any given situation.
+
+A Reviewed-by tag is a statement of opinion that the patch is an
+appropriate modification of the kernel without any remaining serious
+technical issues. Any interested reviewer (who has done the work) can
+offer a Reviewed-by tag for a patch. This tag serves to give credit to
+reviewers and to inform maintainers of the degree of review which has been
+done on the patch. Reviewed-by: tags, when supplied by reviewers known to
+understand the subject area and to perform thorough reviews, will normally
+increase the likelihood of your patch getting into the kernel.
+
+
+15) The canonical patch format
+
+The canonical patch subject line is:
+
+ Subject: [PATCH 001/123] subsystem: summary phrase
+
+The canonical patch message body contains the following:
+
+ - A "from" line specifying the patch author.
+
+ - An empty line.
+
+ - The body of the explanation, which will be copied to the
+ permanent changelog to describe this patch.
+
+ - The "Signed-off-by:" lines, described above, which will
+ also go in the changelog.
+
+ - A marker line containing simply "---".
+
+ - Any additional comments not suitable for the changelog.
+
+ - The actual patch (diff output).
+
+The Subject line format makes it very easy to sort the emails
+alphabetically by subject line - pretty much any email reader will
+support that - since because the sequence number is zero-padded,
+the numerical and alphabetic sort is the same.
+
+The "subsystem" in the email's Subject should identify which
+area or subsystem of the kernel is being patched.
+
+The "summary phrase" in the email's Subject should concisely
+describe the patch which that email contains. The "summary
+phrase" should not be a filename. Do not use the same "summary
+phrase" for every patch in a whole patch series (where a "patch
+series" is an ordered sequence of multiple, related patches).
+
+Bear in mind that the "summary phrase" of your email becomes a
+globally-unique identifier for that patch. It propagates all the way
+into the git changelog. The "summary phrase" may later be used in
+developer discussions which refer to the patch. People will want to
+google for the "summary phrase" to read discussion regarding that
+patch. It will also be the only thing that people may quickly see
+when, two or three months later, they are going through perhaps
+thousands of patches using tools such as "gitk" or "git log
+--oneline".
+
+For these reasons, the "summary" must be no more than 70-75
+characters, and it must describe both what the patch changes, as well
+as why the patch might be necessary. It is challenging to be both
+succinct and descriptive, but that is what a well-written summary
+should do.
+
+The "summary phrase" may be prefixed by tags enclosed in square
+brackets: "Subject: [PATCH tag] <summary phrase>". The tags are not
+considered part of the summary phrase, but describe how the patch
+should be treated. Common tags might include a version descriptor if
+the multiple versions of the patch have been sent out in response to
+comments (i.e., "v1, v2, v3"), or "RFC" to indicate a request for
+comments. If there are four patches in a patch series the individual
+patches may be numbered like this: 1/4, 2/4, 3/4, 4/4. This assures
+that developers understand the order in which the patches should be
+applied and that they have reviewed or applied all of the patches in
+the patch series.
+
+A couple of example Subjects:
+
+ Subject: [patch 2/5] ext2: improve scalability of bitmap searching
+ Subject: [PATCHv2 001/207] x86: fix eflags tracking
+
+The "from" line must be the very first line in the message body,
+and has the form:
+
+ From: Original Author <author@example.com>
+
+The "from" line specifies who will be credited as the author of the
+patch in the permanent changelog. If the "from" line is missing,
+then the "From:" line from the email header will be used to determine
+the patch author in the changelog.
+
+The explanation body will be committed to the permanent source
+changelog, so should make sense to a competent reader who has long
+since forgotten the immediate details of the discussion that might
+have led to this patch. Including symptoms of the failure which the
+patch addresses (kernel log messages, oops messages, etc.) is
+especially useful for people who might be searching the commit logs
+looking for the applicable patch. If a patch fixes a compile failure,
+it may not be necessary to include _all_ of the compile failures; just
+enough that it is likely that someone searching for the patch can find
+it. As in the "summary phrase", it is important to be both succinct as
+well as descriptive.
+
+The "---" marker line serves the essential purpose of marking for patch
+handling tools where the changelog message ends.
+
+One good use for the additional comments after the "---" marker is for
+a diffstat, to show what files have changed, and the number of
+inserted and deleted lines per file. A diffstat is especially useful
+on bigger patches. Other comments relevant only to the moment or the
+maintainer, not suitable for the permanent changelog, should also go
+here. A good example of such comments might be "patch changelogs"
+which describe what has changed between the v1 and v2 version of the
+patch.
+
+If you are going to include a diffstat after the "---" marker, please
+use diffstat options "-p 1 -w 70" so that filenames are listed from
+the top of the kernel source tree and don't use too much horizontal
+space (easily fit in 80 columns, maybe with some indentation).
+
+See more details on the proper patch format in the following
+references.
+
+
+16) Sending "git pull" requests (from Linus emails)
+
+Please write the git repo address and branch name alone on the same line
+so that I can't even by mistake pull from the wrong branch, and so
+that a triple-click just selects the whole thing.
+
+So the proper format is something along the lines of:
+
+ "Please pull from
+
+ git://jdelvare.pck.nerim.net/jdelvare-2.6 i2c-for-linus
+
+ to get these changes:"
+
+so that I don't have to hunt-and-peck for the address and inevitably
+get it wrong (actually, I've only gotten it wrong a few times, and
+checking against the diffstat tells me when I get it wrong, but I'm
+just a lot more comfortable when I don't have to "look for" the right
+thing to pull, and double-check that I have the right branch-name).
+
+
+Please use "git diff -M --stat --summary" to generate the diffstat:
+the -M enables rename detection, and the summary enables a summary of
+new/deleted or renamed files.
+
+With rename detection, the statistics are rather different [...]
+because git will notice that a fair number of the changes are renames.