diff options
Diffstat (limited to 'Documentation/process')
| -rw-r--r-- | Documentation/process/2.Process.rst | 2 | ||||
| -rw-r--r-- | Documentation/process/changes.rst | 15 | ||||
| -rw-r--r-- | Documentation/process/deprecated.rst | 24 | ||||
| -rw-r--r-- | Documentation/process/email-clients.rst | 5 | ||||
| -rw-r--r-- | Documentation/process/programming-language.rst | 9 | ||||
| -rw-r--r-- | Documentation/process/submit-checklist.rst | 4 | ||||
| -rw-r--r-- | Documentation/process/submitting-drivers.rst | 9 | ||||
| -rw-r--r-- | Documentation/process/submitting-patches.rst | 280 |
8 files changed, 97 insertions, 251 deletions
diff --git a/Documentation/process/2.Process.rst b/Documentation/process/2.Process.rst index 4ae1e0f600c1..e05fb1b8f8b6 100644 --- a/Documentation/process/2.Process.rst +++ b/Documentation/process/2.Process.rst @@ -405,7 +405,7 @@ be found at: http://vger.kernel.org/vger-lists.html There are lists hosted elsewhere, though; a number of them are at -lists.redhat.com. +redhat.com/mailman/listinfo. The core mailing list for kernel development is, of course, linux-kernel. This list is an intimidating place to be; volume can reach 500 messages per diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst index ee741763a3fc..dac17711dc11 100644 --- a/Documentation/process/changes.rst +++ b/Documentation/process/changes.rst @@ -30,6 +30,7 @@ you probably needn't concern yourself with pcmciautils. Program Minimal version Command to check the version ====================== =============== ======================================== GNU C 4.9 gcc --version +Clang/LLVM (optional) 10.0.1 clang --version GNU make 3.81 make --version binutils 2.23 ld -v flex 2.5.35 flex --version @@ -68,6 +69,15 @@ GCC The gcc version requirements may vary depending on the type of CPU in your computer. +Clang/LLVM (optional) +--------------------- + +The latest formal release of clang and LLVM utils (according to +`releases.llvm.org <https://releases.llvm.org>`_) are supported for building +kernels. Older releases aren't guaranteed to work, and we may drop workarounds +from the kernel that were used to support older versions. Please see additional +docs on :ref:`Building Linux with Clang/LLVM <kbuild_llvm>`. + Make ---- @@ -331,6 +341,11 @@ gcc - <ftp://ftp.gnu.org/gnu/gcc/> +Clang/LLVM +---------- + +- :ref:`Getting LLVM <getting_llvm>`. + Make ---- diff --git a/Documentation/process/deprecated.rst b/Documentation/process/deprecated.rst index 918e32d76fc4..ff71d802b53d 100644 --- a/Documentation/process/deprecated.rst +++ b/Documentation/process/deprecated.rst @@ -51,24 +51,6 @@ to make sure their systems do not continue running in the face of "unreachable" conditions. (For example, see commits like `this one <https://git.kernel.org/linus/d4689846881d160a4d12a514e991a740bcb5d65a>`_.) -uninitialized_var() -------------------- -For any compiler warnings about uninitialized variables, just add -an initializer. Using the uninitialized_var() macro (or similar -warning-silencing tricks) is dangerous as it papers over `real bugs -<https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/>`_ -(or can in the future), and suppresses unrelated compiler warnings -(e.g. "unused variable"). If the compiler thinks it is uninitialized, -either simply initialize the variable or make compiler changes. Keep in -mind that in most cases, if an initialization is obviously redundant, -the compiler's dead-store elimination pass will make sure there are no -needless variable writes. - -As Linus has said, this macro -`must <https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/>`_ -`be <https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/>`_ -`removed <https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/>`_. - open-coded arithmetic in allocator arguments -------------------------------------------- Dynamic size calculations (especially multiplication) should not be @@ -322,7 +304,8 @@ to allocate for a structure containing an array of this kind as a member:: In the example above, we had to remember to calculate ``count - 1`` when using the struct_size() helper, otherwise we would have --unintentionally-- allocated memory for one too many ``items`` objects. The cleanest and least error-prone way -to implement this is through the use of a `flexible array member`:: +to implement this is through the use of a `flexible array member`, together with +struct_size() and flex_array_size() helpers:: struct something { size_t count; @@ -334,5 +317,4 @@ to implement this is through the use of a `flexible array member`:: instance = kmalloc(struct_size(instance, items, count), GFP_KERNEL); instance->count = count; - size = sizeof(instance->items[0]) * instance->count; - memcpy(instance->items, source, size); + memcpy(instance->items, source, flex_array_size(instance, items, instance->count)); diff --git a/Documentation/process/email-clients.rst b/Documentation/process/email-clients.rst index c9e4ce2613c0..16586f6cc888 100644 --- a/Documentation/process/email-clients.rst +++ b/Documentation/process/email-clients.rst @@ -25,6 +25,11 @@ attachments, but then the attachments should have content-type it makes quoting portions of the patch more difficult in the patch review process. +It's also strongly recommended that you use plain text in your email body, +for patches and other emails alike. https://useplaintext.email may be useful +for information on how to configure your preferred email client, as well as +listing recommended email clients should you not already have a preference. + Email clients that are used for Linux kernel patches should send the patch text untouched. For example, they should not modify or delete tabs or spaces, even at the beginning or end of lines. diff --git a/Documentation/process/programming-language.rst b/Documentation/process/programming-language.rst index e5f5f065dc24..ec474a70a02f 100644 --- a/Documentation/process/programming-language.rst +++ b/Documentation/process/programming-language.rst @@ -6,14 +6,15 @@ Programming Language The kernel is written in the C programming language [c-language]_. More precisely, the kernel is typically compiled with ``gcc`` [gcc]_ under ``-std=gnu89`` [gcc-c-dialect-options]_: the GNU dialect of ISO C90 -(including some C99 features). +(including some C99 features). ``clang`` [clang]_ is also supported, see +docs on :ref:`Building Linux with Clang/LLVM <kbuild_llvm>`. This dialect contains many extensions to the language [gnu-extensions]_, and many of them are used within the kernel as a matter of course. -There is some support for compiling the kernel with ``clang`` [clang]_ -and ``icc`` [icc]_ for several of the architectures, although at the time -of writing it is not completed, requiring third-party patches. +There is some support for compiling the kernel with ``icc`` [icc]_ for several +of the architectures, although at the time of writing it is not completed, +requiring third-party patches. Attributes ---------- diff --git a/Documentation/process/submit-checklist.rst b/Documentation/process/submit-checklist.rst index 3f8e9d5d95c2..b681e862a335 100644 --- a/Documentation/process/submit-checklist.rst +++ b/Documentation/process/submit-checklist.rst @@ -24,6 +24,10 @@ and elsewhere regarding submitting Linux kernel patches. c) Builds successfully when using ``O=builddir`` + d) Any Documentation/ changes build successfully without new warnings/errors. + Use ``make htmldocs`` or ``make pdfdocs`` to check the build and + fix any issues. + 3) Builds on multiple CPU architectures by using local cross-compile tools or some other build farm. diff --git a/Documentation/process/submitting-drivers.rst b/Documentation/process/submitting-drivers.rst index 74b35bfc6623..3861887e0ca5 100644 --- a/Documentation/process/submitting-drivers.rst +++ b/Documentation/process/submitting-drivers.rst @@ -60,10 +60,11 @@ What Criteria Determine Acceptance Licensing: The code must be released to us under the - GNU General Public License. We don't insist on any kind - of exclusive GPL licensing, and if you wish the driver - to be useful to other communities such as BSD you may well - wish to release under multiple licenses. + GNU General Public License. If you wish the driver to be + useful to other communities such as BSD you may release + under multiple licenses. If you choose to release under + licenses other than the GPL, you should include your + rationale for your license choices in your cover letter. See accepted licenses at include/linux/module.h Copyright: diff --git a/Documentation/process/submitting-patches.rst b/Documentation/process/submitting-patches.rst index 5219bf3cddfc..58586ffe2808 100644 --- a/Documentation/process/submitting-patches.rst +++ b/Documentation/process/submitting-patches.rst @@ -10,22 +10,18 @@ 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.rst. - -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 :doc:`development-process`. Also, read :doc:`submit-checklist` +for a list of items to check before submitting code. If you are submitting +a driver, also read :doc:`submitting-drivers`; for device tree binding patches, +read :doc:`submitting-patches`. + +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. + +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 +35,10 @@ 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`` <https://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 @@ -203,8 +141,8 @@ An example call:: .. _split_changes: -3) Separate your changes ------------------------- +Separate your changes +--------------------- Separate each **logical change** into a separate patch. @@ -236,8 +174,8 @@ 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 @@ -267,8 +205,8 @@ 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 @@ -299,7 +237,8 @@ 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 +:doc:`/admin-guide/security-bugs`. Patches that fix a severe bug in a released kernel should be directed toward the stable maintainers by putting a line like this:: @@ -342,15 +281,20 @@ Trivial patches must qualify for one of the following rules: -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:: @@ -366,27 +310,17 @@ 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. - -7) E-mail size --------------- +See :doc:`/process/email-clients` for hints about configuring your e-mail +client so that it sends your patches untouched. -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. @@ -395,9 +329,12 @@ 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. +See :doc:`email-clients` for recommendations on email +clients and mailing list etiquette. -9) Don't get discouraged - or impatient ---------------------------------------- + +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. @@ -410,18 +347,19 @@ one week before resubmitting or pinging reviewers - possibly longer during busy times like merge windows. -10) Include PATCH in the subject --------------------------------- +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 @@ -465,60 +403,15 @@ 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``. 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 - - 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. @@ -586,8 +479,8 @@ 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 @@ -650,8 +543,8 @@ for more details. .. _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 @@ -773,8 +666,8 @@ references. .. _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 @@ -787,8 +680,8 @@ 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) Providing base tree information ------------------------------------ +Providing base tree information +------------------------------- 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 @@ -838,61 +731,6 @@ either below the ``---`` line or at the very bottom of all other content, right before your email signature. -17) 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. - -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:: - - Please pull from - - git://jdelvare.pck.nerim.net/jdelvare-2.6 i2c-for-linus - - 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 -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. - -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. - -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. - -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. - -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. - -When generating your pull request, use the signed tag as the target. A -command like this will do the trick:: - - git request-pull master git://my.public.tree/linux.git my-signed-tag - - References ---------- |