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Diffstat (limited to 'Documentation/SubmittingPatches')
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1 files changed, 105 insertions, 102 deletions
diff --git a/Documentation/SubmittingPatches b/Documentation/SubmittingPatches index 8c79f1d53731..04a4284d8ee4 100644 --- a/Documentation/SubmittingPatches +++ b/Documentation/SubmittingPatches @@ -1,9 +1,6 @@ - How to Get Your Change Into the Linux Kernel - or - Care And Operation Of Your Linus Torvalds - - +How to Get Your Change Into the Linux Kernel or Care And Operation Of Your Linus Torvalds +========================================================================================= For a person or company who wishes to submit a change to the Linux kernel, the process can sometimes be daunting if you're not familiar @@ -24,9 +21,8 @@ of the mechanical work done for you, though you'll still need to prepare and document a sensible set of patches. In general, use of git will make your life as a kernel developer easier. --------------------------------------------- -SECTION 1 - CREATING AND SENDING YOUR CHANGE --------------------------------------------- +Creating and Sending your Change +******************************** 0) Obtain a current source tree @@ -34,35 +30,35 @@ SECTION 1 - CREATING AND SENDING YOUR CHANGE If you do not have a repository with the current kernel source handy, use git to obtain one. You'll want to start with the mainline repository, -which can be grabbed with: +which can be grabbed with:: - git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git + git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Note, however, that you may not want to develop against the mainline tree directly. Most subsystem maintainers run their own trees and want to see -patches prepared against those trees. See the "T:" entry for the subsystem +patches prepared against those trees. See the **T:** entry for the subsystem in the MAINTAINERS file to find that tree, or simply ask the maintainer if the tree is not listed there. It is still possible to download kernel releases via tarballs (as described in the next section), but that is the hard way to do kernel development. -1) "diff -up" ------------- +1) ``diff -up`` +--------------- -If you must generate your patches by hand, use "diff -up" or "diff -uprN" +If you must generate your patches by hand, use ``diff -up`` or ``diff -uprN`` to create patches. Git generates patches in this form by default; if you're using git, you can skip this section entirely. All changes to the Linux kernel occur in the form of patches, as generated by diff(1). When creating your patch, make sure to create it -in "unified diff" format, as supplied by the '-u' argument to diff(1). -Also, please use the '-p' argument which shows which C function each +in "unified diff" format, as supplied by the ``-u`` argument to diff(1). +Also, please use the ``-p`` argument which shows which C function each change is in - that makes the resultant diff a lot easier to read. Patches should be based in the root kernel source directory, not in any lower subdirectory. -To create a patch for a single file, it is often sufficient to do: +To create a patch for a single file, it is often sufficient to do:: SRCTREE= linux MYFILE= drivers/net/mydriver.c @@ -75,7 +71,7 @@ To create a patch for a single file, it is often sufficient to do: To create a patch for multiple files, you should unpack a "vanilla", or unmodified kernel source tree, and generate a diff against your -own source tree. For example: +own source tree. For example:: MYSRC= /devel/linux @@ -84,7 +80,7 @@ own source tree. For example: diff -uprN -X linux-3.19-vanilla/Documentation/dontdiff \ linux-3.19-vanilla $MYSRC > /tmp/patch -"dontdiff" is a list of files which are generated by the kernel during +``dontdiff`` is a list of files which are generated by the kernel during the build process, and should be ignored in any diff(1)-generated patch. @@ -93,18 +89,18 @@ belong in a patch submission. Make sure to review your patch -after- generating it with diff(1), to ensure accuracy. If your changes produce a lot of deltas, you need to split them into -individual patches which modify things in logical stages; see section -#3. This will facilitate review by other kernel developers, +individual patches which modify things in logical stages; see +:ref:`split_changes`. This will facilitate review by other kernel developers, very important if you want your patch accepted. -If you're using git, "git rebase -i" can help you with this process. If +If you're using git, ``git rebase -i`` can help you with this process. If you're not using git, quilt <http://savannah.nongnu.org/projects/quilt> is another popular alternative. +.. _describe_changes: - -2) Describe your changes. -------------------------- +2) Describe your changes +------------------------ Describe your problem. Whether your patch is a one-line bug fix or 5000 lines of a new feature, there must be an underlying problem that @@ -137,11 +133,11 @@ as you intend it to. The maintainer will thank you if you write your patch description in a form which can be easily pulled into Linux's source code management -system, git, as a "commit log". See #15, below. +system, git, as a "commit log". See :ref:`explicit_in_reply_to`. Solve only one problem per patch. If your description starts to get long, that's a sign that you probably need to split up your patch. -See #3, next. +See :ref:`split_changes`. When you submit or resubmit a patch or patch series, include the complete patch description and justification for it. Don't just @@ -171,7 +167,7 @@ patch as submitted. If you want to refer to a specific commit, don't just refer to the SHA-1 ID of the commit. Please also include the oneline summary of the commit, to make it easier for reviewers to know what it is about. -Example: +Example:: Commit e21d2170f36602ae2708 ("video: remove unnecessary platform_set_drvdata()") removed the unnecessary @@ -186,22 +182,24 @@ change five years from now. If your patch fixes a bug in a specific commit, e.g. you found an issue using git-bisect, please use the 'Fixes:' tag with the first 12 characters of the -SHA-1 ID, and the one line summary. For example: +SHA-1 ID, and the one line summary. For example:: Fixes: e21d2170f366 ("video: remove unnecessary platform_set_drvdata()") The following git-config settings can be used to add a pretty format for -outputting the above style in the git log or git show commands +outputting the above style in the git log or git show commands:: [core] abbrev = 12 [pretty] fixes = Fixes: %h (\"%s\") -3) Separate your changes. -------------------------- +.. _split_changes: + +3) Separate your changes +------------------------ -Separate each _logical change_ into a separate patch. +Separate each **logical change** into a separate patch. For example, if your changes include both bug fixes and performance enhancements for a single driver, separate those changes into two @@ -217,12 +215,12 @@ change that can be verified by reviewers. Each patch should be justifiable on its own merits. If one patch depends on another patch in order for a change to be -complete, that is OK. Simply note "this patch depends on patch X" +complete, that is OK. Simply note **"this patch depends on patch X"** in your patch description. When dividing your change into a series of patches, take special care to ensure that the kernel builds and runs properly after each patch in the -series. Developers using "git bisect" to track down a problem can end up +series. Developers using ``git bisect`` to track down a problem can end up splitting your patch series at any point; they will not thank you if you introduce bugs in the middle. @@ -231,8 +229,8 @@ then only post say 15 or so at a time and wait for review and integration. -4) Style-check your changes. ----------------------------- +4) Style-check your changes +--------------------------- Check your patch for basic style violations, details of which can be found in Documentation/CodingStyle. Failure to do so simply wastes @@ -260,8 +258,8 @@ You should be able to justify all violations that remain in your patch. -5) Select the recipients for your patch. ----------------------------------------- +5) Select the recipients for your patch +--------------------------------------- You should always copy the appropriate subsystem maintainer(s) on any patch to code that they maintain; look through the MAINTAINERS file and the @@ -295,7 +293,7 @@ to allow distributors to get the patch out to users; in such cases, obviously, the patch should not be sent to any public lists. Patches that fix a severe bug in a released kernel should be directed -toward the stable maintainers by putting a line like this: +toward the stable maintainers by putting a line like this:: Cc: stable@vger.kernel.org @@ -312,12 +310,14 @@ If changes affect userland-kernel interfaces, please send the MAN-PAGES maintainer (as listed in the MAINTAINERS file) a man-pages patch, or at least a notification of the change, so that some information makes its way into the manual pages. User-space API changes should also be copied to -linux-api@vger.kernel.org. +linux-api@vger.kernel.org. For small patches you may want to CC the Trivial Patch Monkey trivial@kernel.org which collects "trivial" patches. Have a look into the MAINTAINERS file for its current manager. + Trivial patches must qualify for one of the following rules: + Spelling fixes in documentation Spelling fixes for errors which could break grep(1) Warning fixes (cluttering with useless warnings is bad) @@ -332,8 +332,8 @@ Trivial patches must qualify for one of the following rules: -6) No MIME, no links, no compression, no attachments. Just plain text. ------------------------------------------------------------------------ +6) No MIME, no links, no compression, no attachments. Just plain text +---------------------------------------------------------------------- Linus and other kernel developers need to be able to read and comment on the changes you are submitting. It is important for a kernel @@ -356,8 +356,8 @@ you to re-send them using MIME. See Documentation/email-clients.txt for hints about configuring your e-mail client so that it sends your patches untouched. -7) E-mail size. ---------------- +7) E-mail size +-------------- Large changes are not appropriate for mailing lists, and some maintainers. If your patch, uncompressed, exceeds 300 kB in size, @@ -366,8 +366,8 @@ server, and provide instead a URL (link) pointing to your patch. But note that if your patch exceeds 300 kB, it almost certainly needs to be broken up anyway. -8) Respond to review comments. ------------------------------- +8) Respond to review comments +----------------------------- Your patch will almost certainly get comments from reviewers on ways in which the patch can be improved. You must respond to those comments; @@ -382,8 +382,8 @@ reviewers sometimes get grumpy. Even in that case, though, respond politely and address the problems they have pointed out. -9) Don't get discouraged - or impatient. ----------------------------------------- +9) Don't get discouraged - or impatient +--------------------------------------- After you have submitted your change, be patient and wait. Reviewers are busy people and may not get to your patch right away. @@ -419,9 +419,10 @@ patch, which certifies that you wrote it or otherwise have the right to pass it on as an open-source patch. The rules are pretty simple: if you can certify the below: - Developer's Certificate of Origin 1.1 +Developer's Certificate of Origin 1.1 +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - By making a contribution to this project, I certify that: +By making a contribution to this project, I certify that: (a) The contribution was created in whole or in part by me and I have the right to submit it under the open source license @@ -445,7 +446,7 @@ can certify the below: maintained indefinitely and may be redistributed consistent with this project or the open source license(s) involved. -then you just add a line saying +then you just add a line saying:: Signed-off-by: Random J Developer <random@developer.example.org> @@ -466,7 +467,7 @@ 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 : +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] @@ -481,15 +482,15 @@ which appears in the changelog. Special note to back-porters: It seems to be a common and useful practice 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 a 3.x-stable release: +here's what we see in a 3.x-stable release:: -Date: Tue Oct 7 07:26:38 2014 -0400 + Date: Tue Oct 7 07:26:38 2014 -0400 libata: Un-break ATA blacklist commit 1c40279960bcd7d52dbdf1d466b20d24b99176c8 upstream. -And here's what might appear in an older kernel once a patch is backported: +And here's what might appear in an older kernel once a patch is backported:: Date: Tue May 13 22:12:27 2008 +0200 @@ -529,7 +530,7 @@ 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. +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 - but it should indicate that this person was copied on the patch. This tag documents that potentially interested parties @@ -552,11 +553,12 @@ 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 +Reviewer's statement of oversight +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - By offering my Reviewed-by: tag, I state that: +By offering my Reviewed-by: tag, I state that: - (a) I have carried out a technical review of this patch to + (a) I have carried out a technical review of this patch to evaluate its appropriateness and readiness for inclusion into the mainline kernel. @@ -594,7 +596,8 @@ A Fixes: tag indicates that the patch fixes an issue in a previous commit. It is used to make it easy to determine where a bug originated, which can help review a bug fix. This tag also assists the stable kernel team in determining which stable kernel versions should receive your fix. This is the preferred -method for indicating a bug fixed by the patch. See #2 above for more details. +method for indicating a bug fixed by the patch. See :ref:`describe_changes` +for more details. 14) The canonical patch format @@ -602,16 +605,16 @@ method for indicating a bug fixed by the patch. See #2 above for more details. This section describes how the patch itself should be formatted. Note that, if you have your patches stored in a git repository, proper patch -formatting can be had with "git format-patch". The tools cannot create +formatting can be had with ``git format-patch``. The tools cannot create the necessary text, though, so read the instructions below anyway. -The canonical patch subject line is: +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 (only needed if the person + - A ``from`` line specifying the patch author (only needed if the person sending the patch is not the author). - An empty line. @@ -619,10 +622,10 @@ The canonical patch message body contains the following: - The body of the explanation, line wrapped at 75 columns, which will be copied to the permanent changelog to describe this patch. - - The "Signed-off-by:" lines, described above, which will + - The ``Signed-off-by:`` lines, described above, which will also go in the changelog. - - A marker line containing simply "---". + - A marker line containing simply ``---``. - Any additional comments not suitable for the changelog. @@ -633,32 +636,32 @@ 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 +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). +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 +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 +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 +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 +thousands of patches using tools such as ``gitk`` or "git log --oneline". -For these reasons, the "summary" must be no more than 70-75 +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 +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 @@ -670,19 +673,19 @@ 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: +A couple of example Subjects:: Subject: [PATCH 2/5] ext2: improve scalability of bitmap searching Subject: [PATCH v2 01/27] x86: fix eflags tracking -The "from" line must be the very first line in the message body, +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 ``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 @@ -694,23 +697,23 @@ 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 +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 +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 +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" +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 +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). (git generates appropriate diffstats by default.) @@ -718,11 +721,13 @@ generates appropriate diffstats by default.) See more details on the proper patch format in the following references. +.. _explicit_in_reply_to: + 15) Explicit In-Reply-To headers -------------------------------- It can be helpful to manually add In-Reply-To: headers to a patch -(e.g., when using "git send-email") to associate the patch with +(e.g., when using ``git send-email``) to associate the patch with previous relevant discussion, e.g. to link a bug fix to the email with the bug report. However, for a multi-patch series, it is generally best to avoid using In-Reply-To: to link to older versions of the @@ -732,12 +737,12 @@ helpful, you can use the https://lkml.kernel.org/ redirector (e.g., in the cover email text) to link to an earlier version of the patch series. -16) Sending "git pull" requests -------------------------------- +16) Sending ``git pull`` requests +--------------------------------- If you have a series of patches, it may be most convenient to have the maintainer pull them directly into the subsystem repository with a -"git pull" operation. Note, however, that pulling patches from a developer +``git pull`` operation. Note, however, that pulling patches from a developer requires a higher degree of trust than taking patches from a mailing list. As a result, many subsystem maintainers are reluctant to take pull requests, especially from new, unknown developers. If in doubt you can use @@ -746,7 +751,7 @@ series, giving the maintainer the option of using either. A pull request should have [GIT] or [PULL] in the subject line. The request itself should include the repository name and the branch of -interest on a single line; it should look something like: +interest on a single line; it should look something like:: Please pull from @@ -755,10 +760,10 @@ interest on a single line; it should look something like: to get these changes: A pull request should also include an overall message saying what will be -included in the request, a "git shortlog" listing of the patches +included in the request, a ``git shortlog`` listing of the patches themselves, and a diffstat showing the overall effect of the patch series. The easiest way to get all this information together is, of course, to let -git do it for you with the "git request-pull" command. +git do it for you with the ``git request-pull`` command. Some maintainers (including Linus) want to see pull requests from signed commits; that increases their confidence that the request actually came @@ -771,7 +776,7 @@ new developers, but there is no way around it. Attending conferences can be a good way to find developers who can sign your key. Once you have prepared a patch series in git that you wish to have somebody -pull, create a signed tag with "git tag -s". This will create a new tag +pull, create a signed tag with ``git tag -s``. This will create a new tag identifying the last commit in the series and containing a signature created with your private key. You will also have the opportunity to add a changelog-style message to the tag; this is an ideal place to describe the @@ -782,14 +787,13 @@ are working from, don't forget to push the signed tag explicitly to the public tree. When generating your pull request, use the signed tag as the target. A -command like this will do the trick: +command like this will do the trick:: git request-pull master git://my.public.tree/linux.git my-signed-tag ----------------------- -SECTION 2 - REFERENCES ----------------------- +REFERENCES +********** Andrew Morton, "The perfect patch" (tpp). <http://www.ozlabs.org/~akpm/stuff/tpp.txt> @@ -818,4 +822,3 @@ Andi Kleen, "On submitting kernel patches" Some strategies to get difficult or controversial changes in. http://halobates.de/on-submitting-patches.pdf --- |