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diff --git a/Documentation/process/submitting-patches.rst b/Documentation/process/submitting-patches.rst index 9c4299293c72..a1cb6280fbcf 100644 --- a/Documentation/process/submitting-patches.rst +++ b/Documentation/process/submitting-patches.rst @@ -10,22 +10,24 @@ can greatly increase the chances of your change being accepted. This document contains a large number of suggestions in a relatively terse format. For detailed information on how the kernel development process -works, see :ref:`Documentation/process <development_process_main>`. -Also, read :ref:`Documentation/process/submit-checklist.rst <submitchecklist>` -for a list of items to check before -submitting code. If you are submitting a driver, also read -:ref:`Documentation/process/submitting-drivers.rst <submittingdrivers>`; -for device tree binding patches, read -Documentation/devicetree/bindings/submitting-patches.txt. - -Many of these steps describe the default behavior of the ``git`` version -control system; if you use ``git`` to prepare your patches, you'll find much -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. - -0) Obtain a current source tree -------------------------------- +works, see Documentation/process/development-process.rst. Also, read +Documentation/process/submit-checklist.rst +for a list of items to check before submitting code. If you are submitting +a driver, also read Documentation/process/submitting-drivers.rst; for device +tree binding patches, read +Documentation/devicetree/bindings/submitting-patches.rst. + +This documentation assumes that you're using ``git`` to prepare your patches. +If you're unfamiliar with ``git``, you would be well-advised to learn how to +use it, it will make your life as a kernel developer and in general much +easier. + +Some subsystems and maintainer trees have additional information about +their workflow and expectations, see +:ref:`Documentation/process/maintainer-handbooks.rst <maintainer_handbooks_main>`. + +Obtain a current source tree +---------------------------- 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, @@ -39,68 +41,10 @@ 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`` ---------------- - -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 :manpage:`diff(1)`. When creating your patch, make sure to -create it in "unified diff" format, as supplied by the ``-u`` argument -to :manpage:`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:: - - SRCTREE=linux - MYFILE=drivers/net/mydriver.c - - cd $SRCTREE - cp $MYFILE $MYFILE.orig - vi $MYFILE # make your change - cd .. - diff -up $SRCTREE/$MYFILE{.orig,} > /tmp/patch - -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:: - - MYSRC=/devel/linux - - tar xvfz linux-3.19.tar.gz - mv linux-3.19 linux-3.19-vanilla - 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 -the build process, and should be ignored in any :manpage:`diff(1)`-generated -patch. - -Make sure your patch does not include any extra files which do not -belong in a patch submission. Make sure to review your patch -after- -generating it with :manpage:`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 -: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 -you're not using ``git``, ``quilt`` <http://savannah.nongnu.org/projects/quilt> -is another popular alternative. - .. _describe_changes: -2) Describe your changes ------------------------- +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 @@ -133,7 +77,7 @@ 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 :ref:`explicit_in_reply_to`. +system, ``git``, as a "commit log". See :ref:`the_canonical_patch_format`. 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. @@ -153,17 +97,6 @@ instead of "[This patch] makes xyzzy do frotz" or "[I] changed xyzzy to do frotz", as if you are giving orders to the codebase to change its behaviour. -If the patch fixes a logged bug entry, refer to that bug entry by -number and URL. If the patch follows from a mailing list discussion, -give a URL to the mailing list archive; use the https://lkml.kernel.org/ -redirector with a ``Message-Id``, to ensure that the links cannot become -stale. - -However, try to make your explanation understandable without external -resources. In addition to giving a URL to a mailing list archive or -bug, summarize the relevant points of the discussion that led to the -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. @@ -180,6 +113,28 @@ collisions with shorter IDs a real possibility. Bear in mind that, even if there is no collision with your six-character ID now, that condition may change five years from now. +If related discussions or any other background information behind the change +can be found on the web, add 'Link:' tags pointing to it. In case your patch +fixes a bug, for example, add a tag with a URL referencing the report in the +mailing list archives or a bug tracker; if the patch is a result of some +earlier mailing list discussion or something documented on the web, point to +it. + +When linking to mailing list archives, preferably use the lore.kernel.org +message archiver service. To create the link URL, use the contents of the +``Message-Id`` header of the message without the surrounding angle brackets. +For example:: + + Link: https://lore.kernel.org/r/30th.anniversary.repost@klaava.Helsinki.FI/ + +Please check the link to make sure that it is actually working and points +to the relevant message. + +However, try to make your explanation understandable without external +resources. In addition to giving a URL to a mailing list archive or bug, +summarize the relevant points of the discussion that led to the +patch as submitted. + 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. Do not split the tag across multiple @@ -196,10 +151,15 @@ outputting the above style in the ``git log`` or ``git show`` commands:: [pretty] fixes = Fixes: %h (\"%s\") +An example call:: + + $ git log -1 --pretty=fixes 54a4f0239f2e + Fixes: 54a4f0239f2e ("KVM: MMU: make kvm_mmu_zap_page() return the number of pages it actually freed") + .. _split_changes: -3) Separate your changes ------------------------- +Separate your changes +--------------------- Separate each **logical change** into a separate patch. @@ -231,12 +191,11 @@ then only post say 15 or so at a time and wait for review and integration. -4) Style-check your changes ---------------------------- +Style-check your changes +------------------------ Check your patch for basic style violations, details of which can be -found in -:ref:`Documentation/process/coding-style.rst <codingstyle>`. +found in Documentation/process/coding-style.rst. Failure to do so simply wastes the reviewers time and will get your patch rejected, probably without even being read. @@ -262,22 +221,23 @@ You should be able to justify all violations that remain in your patch. -5) Select the recipients for your patch ---------------------------------------- +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 source code revision history to see who those maintainers are. The -script scripts/get_maintainer.pl can be very useful at this step. If you -cannot find a maintainer for the subsystem you are working on, Andrew -Morton (akpm@linux-foundation.org) serves as a maintainer of last resort. +script scripts/get_maintainer.pl can be very useful at this step (pass paths to +your patches as arguments to scripts/get_maintainer.pl). If you cannot find a +maintainer for the subsystem you are working on, Andrew Morton +(akpm@linux-foundation.org) serves as a maintainer of last resort. You should also normally choose at least one mailing list to receive a copy -of your patch set. linux-kernel@vger.kernel.org functions as a list of -last resort, but the volume on that list has caused a number of developers -to tune it out. Look in the MAINTAINERS file for a subsystem-specific -list; your patch will probably get more attention there. Please do not -spam unrelated lists, though. +of your patch set. linux-kernel@vger.kernel.org should be used by default +for all patches, but the volume on that list has caused a number of +developers to tune it out. Look in the MAINTAINERS file for a +subsystem-specific list; your patch will probably get more attention there. +Please do not spam unrelated lists, though. Many kernel-related lists are hosted on vger.kernel.org; you can find a list of them at http://vger.kernel.org/vger-lists.html. There are @@ -294,7 +254,8 @@ sending him e-mail. If you have a patch that fixes an exploitable security bug, send that patch to security@kernel.org. For severe bugs, a short embargo may be considered to allow distributors to get the patch out to users; in such cases, -obviously, the patch should not be sent to any public lists. +obviously, the patch should not be sent to any public lists. See also +Documentation/admin-guide/security-bugs.rst. Patches that fix a severe bug in a released kernel should be directed toward the stable maintainers by putting a line like this:: @@ -302,14 +263,8 @@ toward the stable maintainers by putting a line like this:: Cc: stable@vger.kernel.org into the sign-off area of your patch (note, NOT an email recipient). You -should also read -:ref:`Documentation/process/stable-kernel-rules.rst <stable_kernel_rules>` -in addition to this file. - -Note, however, that some subsystem maintainers want to come to their own -conclusions on which patches should go to the stable trees. The networking -maintainer, in particular, would rather not see individual developers -adding lines like the above to their patches. +should also read Documentation/process/stable-kernel-rules.rst +in addition to this document. If changes affect userland-kernel interfaces, please send the MAN-PAGES maintainer (as listed in the MAINTAINERS file) a man-pages patch, or at @@ -317,35 +272,21 @@ 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. -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 :manpage:`grep(1)` -- Warning fixes (cluttering with useless warnings is bad) -- Compilation fixes (only if they are actually correct) -- Runtime fixes (only if they actually fix things) -- Removing use of deprecated functions/macros -- Contact detail and documentation fixes -- Non-portable code replaced by portable code (even in arch-specific, - since people copy, as long as it's trivial) -- Any fix by the author/maintainer of the file (ie. patch monkey - in re-transmission mode) - - - -6) No MIME, no links, no compression, no attachments. Just plain text ----------------------------------------------------------------------- +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 developer to be able to "quote" your changes, using standard e-mail tools, so that they may comment on specific portions of your code. -For this reason, all patches should be submitted by e-mail "inline". +For this reason, all patches should be submitted by e-mail "inline". The +easiest way to do this is with ``git send-email``, which is strongly +recommended. An interactive tutorial for ``git send-email`` is available at +https://git-send-email.io. + +If you choose not to use ``git send-email``: .. warning:: @@ -361,38 +302,35 @@ decreasing the likelihood of your MIME-attached change being accepted. Exception: If your mailer is mangling patches then someone may ask you to re-send them using MIME. -See :ref:`Documentation/process/email-clients.rst <email_clients>` -for hints about configuring your e-mail client so that it sends your patches -untouched. +See Documentation/process/email-clients.rst for hints about configuring +your e-mail client so that it sends your patches untouched. -7) E-mail size --------------- - -Large changes are not appropriate for mailing lists, and some -maintainers. If your patch, uncompressed, exceeds 300 kB in size, -it is preferred that you store your patch on an Internet-accessible -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 ------------------------------ +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; -ignoring reviewers is a good way to get ignored in return. Review comments -or questions that do not lead to a code change should almost certainly +which the patch can be improved, in the form of a reply to your email. You must +respond to those comments; ignoring reviewers is a good way to get ignored in +return. You can simply reply to their emails to answer their comments. Review +comments or questions that do not lead to a code change should almost certainly bring about a comment or changelog entry so that the next reviewer better understands what is going on. Be sure to tell the reviewers what changes you are making and to thank them for their time. Code review is a tiring and time-consuming process, and reviewers sometimes get grumpy. Even in that case, though, respond -politely and address the problems they have pointed out. +politely and address the problems they have pointed out. When sending a next +version, add a ``patch changelog`` to the cover letter or to individual patches +explaining difference aganst previous submission (see +:ref:`the_canonical_patch_format`). +See Documentation/process/email-clients.rst for recommendations on email +clients and mailing list etiquette. -9) Don't get discouraged - or impatient ---------------------------------------- +.. _resend_reminders: + +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. @@ -404,19 +342,30 @@ that you have sent your patches to the right place. Wait for a minimum of one week before resubmitting or pinging reviewers - possibly longer during busy times like merge windows. +It's also ok to resend the patch or the patch series after a couple of +weeks with the word "RESEND" added to the subject line:: + + [PATCH Vx RESEND] sub/sys: Condensed patch summary -10) Include PATCH in the subject --------------------------------- +Don't add "RESEND" when you are submitting a modified version of your +patch or patch series - "RESEND" only applies to resubmission of a +patch or patch series which have not been modified in any way from the +previous submission. + + +Include PATCH in the subject +----------------------------- Due to high e-mail traffic to Linus, and to linux-kernel, it is common convention to prefix your subject line with [PATCH]. This lets Linus and other kernel developers more easily distinguish patches from other e-mail discussions. +``git send-email`` will do this for you automatically. -11) Sign your work - the Developer's Certificate of Origin ----------------------------------------------------------- +Sign your work - the Developer's Certificate of Origin +------------------------------------------------------ To improve tracking of who did what, especially with patches that can percolate to their final resting place in the kernel through several @@ -460,60 +409,23 @@ then you just add a line saying:: Signed-off-by: Random J Developer <random@developer.example.org> using your real name (sorry, no pseudonyms or anonymous contributions.) +This will be done for you automatically if you use ``git commit -s``. +Reverts should also include "Signed-off-by". ``git revert -s`` does that +for you. Some people also put extra tags at the end. They'll just be ignored for now, but you can do this to mark internal company procedures or just point out some special detail about the sign-off. -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 practice 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 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:: - - Date: Tue Oct 7 07:26:38 2014 -0400 - - libata: Un-break ATA blacklist +Any further SoBs (Signed-off-by:'s) following the author's SoB are from +people handling and transporting the patch, but were not involved in its +development. SoB chains should reflect the **real** route a patch took +as it was propagated to the maintainers and ultimately to Linus, with +the first SoB entry signalling primary authorship of a single author. - commit 1c40279960bcd7d52dbdf1d466b20d24b99176c8 upstream. -And here's what might appear in an older kernel once a patch is backported:: - - 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 troubleshoot bugs in your -tree. - - -12) When to use Acked-by:, Cc:, and Co-developed-by: -------------------------------------------------------- +When to use Acked-by:, Cc:, and Co-developed-by: +------------------------------------------------ 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. @@ -546,7 +458,7 @@ patch. This tag documents that potentially interested parties have been included in the discussion. Co-developed-by: states that the patch was co-created by multiple developers; -it is a used to give attribution to co-authors (in addition to the author +it is used to give attribution to co-authors (in addition to the author attributed by the From: tag) when several people work on a single patch. Since Co-developed-by: denotes authorship, every Co-developed-by: must be immediately followed by a Signed-off-by: of the associated co-author. Standard sign-off @@ -581,13 +493,14 @@ Example of a patch submitted by a Co-developed-by: author:: Signed-off-by: Submitting Co-Author <sub@coauthor.example.org> -13) Using Reported-by:, Tested-by:, Reviewed-by:, Suggested-by: and Fixes: --------------------------------------------------------------------------- +Using Reported-by:, Tested-by:, Reviewed-by:, Suggested-by: and Fixes: +---------------------------------------------------------------------- The Reported-by tag gives credit to people who find bugs and report them and it hopefully inspires them to help us again in the future. Please note that if the bug was reported in private, then ask for permission first before using the -Reported-by tag. +Reported-by tag. The tag is intended for bugs; please do not use it to credit +feature requests. A Tested-by: tag indicates that the patch has been successfully tested (in some environment) by the person named. This tag informs maintainers that @@ -629,6 +542,13 @@ 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. +Both Tested-by and Reviewed-by tags, once received on mailing list from tester +or reviewer, should be added by author to the applicable patches when sending +next versions. However if the patch has changed substantially in following +version, these tags might not be applicable anymore and thus should be removed. +Usually removal of someone's Tested-by or Reviewed-by tags should be mentioned +in the patch changelog (after the '---' separator). + A Suggested-by: tag indicates that the patch idea is suggested by the person named and ensures credit to the person for the idea. Please note that this tag should not be added without the reporter's permission, especially if the @@ -643,10 +563,15 @@ which stable kernel versions should receive your fix. This is the preferred method for indicating a bug fixed by the patch. See :ref:`describe_changes` for more details. +Note: Attaching a Fixes: tag does not subvert the stable kernel rules +process nor the requirement to Cc: stable@vger.kernel.org on all stable +patch candidates. For more information, please read +Documentation/process/stable-kernel-rules.rst. + .. _the_canonical_patch_format: -14) The canonical patch format ------------------------------- +The canonical patch format +-------------------------- This section describes how the patch itself should be formatted. Note that, if you have your patches stored in a ``git`` repository, proper patch @@ -712,16 +637,19 @@ 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. +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:: +Here are some good example Subjects:: Subject: [PATCH 2/5] ext2: improve scalability of bitmap searching Subject: [PATCH v2 01/27] x86: fix eflags tracking + Subject: [PATCH v2] sub/sys: Condensed patch summary + Subject: [PATCH v2 M/N] sub/sys: Condensed patch summary The ``from`` line must be the very first line in the message body, and has the form: @@ -734,42 +662,84 @@ 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). (``git`` -generates appropriate diffstats by default.) +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.) are especially useful for +people who might be searching the commit logs looking for the applicable +patch. The text should be written in such detail so that when read +weeks, months or even years later, it can give the reader the needed +details to grasp the reasoning for **why** the patch was created. + +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. 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.) + +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. + +Please put this information **after** the ``---`` line which separates +the changelog from the rest of the patch. The version information is +not part of the changelog which gets committed to the git tree. It is +additional information for the reviewers. If it's placed above the +commit tags, it needs manual interaction to remove it. If it is below +the separator line, it gets automatically stripped off when applying the +patch:: + + <commit message> + ... + Signed-off-by: Author <author@mail> + --- + V2 -> V3: Removed redundant helper function + V1 -> V2: Cleaned up coding style and addressed review comments + + path/to/file | 5+++-- + ... See more details on the proper patch format in the following references. +.. _backtraces: + +Backtraces in commit mesages +^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Backtraces help document the call chain leading to a problem. However, +not all backtraces are helpful. For example, early boot call chains are +unique and obvious. Copying the full dmesg output verbatim, however, +adds distracting information like timestamps, module lists, register and +stack dumps. + +Therefore, the most useful backtraces should distill the relevant +information from the dump, which makes it easier to focus on the real +issue. Here is an example of a well-trimmed backtrace:: + + unchecked MSR access error: WRMSR to 0xd51 (tried to write 0x0000000000000064) + at rIP: 0xffffffffae059994 (native_write_msr+0x4/0x20) + Call Trace: + mba_wrmsr + update_domains + rdtgroup_mkdir + .. _explicit_in_reply_to: -15) Explicit In-Reply-To headers --------------------------------- +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 @@ -778,73 +748,69 @@ 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 series. This way multiple versions of the patch don't become an unmanageable forest of references in email clients. If a link is -helpful, you can use the https://lkml.kernel.org/ redirector (e.g., in +helpful, you can use the https://lore.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 ---------------------------------- - -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 -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 -the pull request as the cover letter for a normal posting of the patch -series, giving the maintainer the option of using either. +Providing base tree information +------------------------------- -A pull request should have [GIT 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:: +When other developers receive your patches and start the review process, +it is often useful for them to know where in the tree history they +should place your work. This is particularly useful for automated CI +processes that attempt to run a series of tests in order to establish +the quality of your submission before the maintainer starts the review. - Please pull from +If you are using ``git format-patch`` to generate your patches, you can +automatically include the base tree information in your submission by +using the ``--base`` flag. The easiest and most convenient way to use +this option is with topical branches:: - git://jdelvare.pck.nerim.net/jdelvare-2.6 i2c-for-linus + $ git checkout -t -b my-topical-branch master + Branch 'my-topical-branch' set up to track local branch 'master'. + Switched to a new branch 'my-topical-branch' - to get these changes: + [perform your edits and commits] -A pull request should also include an overall message saying what will be -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 format-patch --base=auto --cover-letter -o outgoing/ master + outgoing/0000-cover-letter.patch + outgoing/0001-First-Commit.patch + outgoing/... -Some maintainers (including Linus) want to see pull requests from signed -commits; that increases their confidence that the request actually came -from you. Linus, in particular, will not pull from public hosting sites -like GitHub in the absence of a signed tag. +When you open ``outgoing/0000-cover-letter.patch`` for editing, you will +notice that it will have the ``base-commit:`` trailer at the very +bottom, which provides the reviewer and the CI tools enough information +to properly perform ``git am`` without worrying about conflicts:: -The first step toward creating such tags is to make a GNUPG key and get it -signed by one or more core kernel developers. This step can be hard for -new developers, but there is no way around it. Attending conferences can -be a good way to find developers who can sign your key. + $ git checkout -b patch-review [base-commit-id] + Switched to a new branch 'patch-review' + $ git am patches.mbox + Applying: First Commit + Applying: ... -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 -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 -effects of the pull request as a whole. +Please see ``man git-format-patch`` for more information about this +option. -If the tree the maintainer will be pulling from is not the repository you -are working from, don't forget to push the signed tag explicitly to the -public tree. +.. note:: -When generating your pull request, use the signed tag as the target. A -command like this will do the trick:: + The ``--base`` feature was introduced in git version 2.9.0. - git request-pull master git://my.public.tree/linux.git my-signed-tag +If you are not using git to format your patches, you can still include +the same ``base-commit`` trailer to indicate the commit hash of the tree +on which your work is based. You should add it either in the cover +letter or in the first patch of the series and it should be placed +either below the ``---`` line or at the very bottom of all other +content, right before your email signature. References ---------- Andrew Morton, "The perfect patch" (tpp). - <http://www.ozlabs.org/~akpm/stuff/tpp.txt> + <https://www.ozlabs.org/~akpm/stuff/tpp.txt> Jeff Garzik, "Linux kernel patch submission format". - <http://linux.yyz.us/patch-format.html> + <https://web.archive.org/web/20180829112450/http://linux.yyz.us/patch-format.html> Greg Kroah-Hartman, "How to piss off a kernel subsystem maintainer". <http://www.kroah.com/log/linux/maintainer.html> @@ -860,13 +826,12 @@ Greg Kroah-Hartman, "How to piss off a kernel subsystem maintainer". <http://www.kroah.com/log/linux/maintainer-06.html> NO!!!! No more huge patch bombs to linux-kernel@vger.kernel.org people! - <https://lkml.org/lkml/2005/7/11/336> + <https://lore.kernel.org/r/20050711.125305.08322243.davem@davemloft.net> -Kernel Documentation/process/coding-style.rst: - :ref:`Documentation/process/coding-style.rst <codingstyle>` +Kernel Documentation/process/coding-style.rst Linus Torvalds's mail on the canonical patch format: - <http://lkml.org/lkml/2005/4/7/183> + <https://lore.kernel.org/r/Pine.LNX.4.58.0504071023190.28951@ppc970.osdl.org> Andi Kleen, "On submitting kernel patches" Some strategies to get difficult or controversial changes in. |