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diff --git a/Documentation/process/maintainer-netdev.rst b/Documentation/process/maintainer-netdev.rst index d14007081595..fd96e4a3cef9 100644 --- a/Documentation/process/maintainer-netdev.rst +++ b/Documentation/process/maintainer-netdev.rst @@ -2,9 +2,9 @@ .. _netdev-FAQ: -========== -netdev FAQ -========== +============================= +Networking subsystem (netdev) +============================= tl;dr ----- @@ -15,14 +15,15 @@ tl;dr - don't repost your patches within one 24h period - reverse xmas tree -What is netdev? ---------------- -It is a mailing list for all network-related Linux stuff. This +netdev +------ + +netdev is a mailing list for all network-related Linux stuff. This includes anything found under net/ (i.e. core code like IPv6) and drivers/net (i.e. hardware specific drivers) in the Linux source tree. Note that some subsystems (e.g. wireless drivers) which have a high -volume of traffic have their own specific mailing lists. +volume of traffic have their own specific mailing lists and trees. The netdev list is managed (like many other Linux mailing lists) through VGER (http://vger.kernel.org/) with archives available at @@ -32,32 +33,10 @@ Aside from subsystems like those mentioned above, all network-related Linux development (i.e. RFC, review, comments, etc.) takes place on netdev. -How do the changes posted to netdev make their way into Linux? --------------------------------------------------------------- -There are always two trees (git repositories) in play. Both are -driven by David Miller, the main network maintainer. There is the -``net`` tree, and the ``net-next`` tree. As you can probably guess from -the names, the ``net`` tree is for fixes to existing code already in the -mainline tree from Linus, and ``net-next`` is where the new code goes -for the future release. You can find the trees here: - -- https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git -- https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git +Development cycle +----------------- -How do I indicate which tree (net vs. net-next) my patch should be in? ----------------------------------------------------------------------- -To help maintainers and CI bots you should explicitly mark which tree -your patch is targeting. Assuming that you use git, use the prefix -flag:: - - git format-patch --subject-prefix='PATCH net-next' start..finish - -Use ``net`` instead of ``net-next`` (always lower case) in the above for -bug-fix ``net`` content. - -How often do changes from these trees make it to the mainline Linus tree? -------------------------------------------------------------------------- -To understand this, you need to know a bit of background information on +Here is a bit of background information on the cadence of Linux development. Each new release starts off with a two week "merge window" where the main maintainers feed their new stuff to Linus for merging into the mainline tree. After the two weeks, the @@ -69,9 +48,33 @@ rc2 is released. This repeats on a roughly weekly basis until rc7 state of churn), and a week after the last vX.Y-rcN was done, the official vX.Y is released. -Relating that to netdev: At the beginning of the 2-week merge window, -the ``net-next`` tree will be closed - no new changes/features. The -accumulated new content of the past ~10 weeks will be passed onto +To find out where we are now in the cycle - load the mainline (Linus) +page here: + + https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git + +and note the top of the "tags" section. If it is rc1, it is early in +the dev cycle. If it was tagged rc7 a week ago, then a release is +probably imminent. If the most recent tag is a final release tag +(without an ``-rcN`` suffix) - we are most likely in a merge window +and ``net-next`` is closed. + +git trees and patch flow +------------------------ + +There are two networking trees (git repositories) in play. Both are +driven by David Miller, the main network maintainer. There is the +``net`` tree, and the ``net-next`` tree. As you can probably guess from +the names, the ``net`` tree is for fixes to existing code already in the +mainline tree from Linus, and ``net-next`` is where the new code goes +for the future release. You can find the trees here: + +- https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git +- https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git + +Relating that to kernel development: At the beginning of the 2-week +merge window, the ``net-next`` tree will be closed - no new changes/features. +The accumulated new content of the past ~10 weeks will be passed onto mainline/Linus via a pull request for vX.Y -- at the same time, the ``net`` tree will start accumulating fixes for this pulled content relating to vX.Y @@ -95,7 +98,7 @@ If you aren't subscribed to netdev and/or are simply unsure if repository link above for any new networking-related commits. You may also check the following website for the current status: - http://vger.kernel.org/~davem/net-next.html + https://netdev.bots.linux.dev/net-next.html The ``net`` tree continues to collect fixes for the vX.Y content, and is fed back to Linus at regular (~weekly) intervals. Meaning that the @@ -103,97 +106,261 @@ focus for ``net`` is on stabilization and bug fixes. Finally, the vX.Y gets released, and the whole cycle starts over. -So where are we now in this cycle? ----------------------------------- +netdev patch review +------------------- -Load the mainline (Linus) page here: +.. _patch_status: - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git - -and note the top of the "tags" section. If it is rc1, it is early in -the dev cycle. If it was tagged rc7 a week ago, then a release is -probably imminent. If the most recent tag is a final release tag -(without an ``-rcN`` suffix) - we are most likely in a merge window -and ``net-next`` is closed. +Patch status +~~~~~~~~~~~~ -How can I tell the status of a patch I've sent? ------------------------------------------------ -Start by looking at the main patchworks queue for netdev: +Status of a patch can be checked by looking at the main patchwork +queue for netdev: https://patchwork.kernel.org/project/netdevbpf/list/ The "State" field will tell you exactly where things are at with your -patch. Patches are indexed by the ``Message-ID`` header of the emails +patch: + +================== ============================================================= +Patch state Description +================== ============================================================= +New, Under review pending review, patch is in the maintainer’s queue for + review; the two states are used interchangeably (depending on + the exact co-maintainer handling patchwork at the time) +Accepted patch was applied to the appropriate networking tree, this is + usually set automatically by the pw-bot +Needs ACK waiting for an ack from an area expert or testing +Changes requested patch has not passed the review, new revision is expected + with appropriate code and commit message changes +Rejected patch has been rejected and new revision is not expected +Not applicable patch is expected to be applied outside of the networking + subsystem +Awaiting upstream patch should be reviewed and handled by appropriate + sub-maintainer, who will send it on to the networking trees; + patches set to ``Awaiting upstream`` in netdev's patchwork + will usually remain in this state, whether the sub-maintainer + requested changes, accepted or rejected the patch +Deferred patch needs to be reposted later, usually due to dependency + or because it was posted for a closed tree +Superseded new version of the patch was posted, usually set by the + pw-bot +RFC not to be applied, usually not in maintainer’s review queue, + pw-bot can automatically set patches to this state based + on subject tags +================== ============================================================= + +Patches are indexed by the ``Message-ID`` header of the emails which carried them so if you have trouble finding your patch append the value of ``Message-ID`` to the URL above. -How long before my patch is accepted? -------------------------------------- +Updating patch status +~~~~~~~~~~~~~~~~~~~~~ + +Contributors and reviewers do not have the permissions to update patch +state directly in patchwork. Patchwork doesn't expose much information +about the history of the state of patches, therefore having multiple +people update the state leads to confusion. + +Instead of delegating patchwork permissions netdev uses a simple mail +bot which looks for special commands/lines within the emails sent to +the mailing list. For example to mark a series as Changes Requested +one needs to send the following line anywhere in the email thread:: + + pw-bot: changes-requested + +As a result the bot will set the entire series to Changes Requested. +This may be useful when author discovers a bug in their own series +and wants to prevent it from getting applied. + +The use of the bot is entirely optional, if in doubt ignore its existence +completely. Maintainers will classify and update the state of the patches +themselves. No email should ever be sent to the list with the main purpose +of communicating with the bot, the bot commands should be seen as metadata. + +The use of the bot is restricted to authors of the patches (the ``From:`` +header on patch submission and command must match!), maintainers of +the modified code according to the MAINTAINERS file (again, ``From:`` +must match the MAINTAINERS entry) and a handful of senior reviewers. + +Bot records its activity here: + + https://netdev.bots.linux.dev/pw-bot.html + +Review timelines +~~~~~~~~~~~~~~~~ + Generally speaking, the patches get triaged quickly (in less than 48h). But be patient, if your patch is active in patchwork (i.e. it's listed on the project's patch list) the chances it was missed are close to zero. -Asking the maintainer for status updates on your -patch is a good way to ensure your patch is ignored or pushed to the -bottom of the priority list. - -Should I directly update patchwork state of my own patches? ------------------------------------------------------------ -It may be tempting to help the maintainers and update the state of your -own patches when you post a new version or spot a bug. Please do not do that. -Interfering with the patch status on patchwork will only cause confusion. Leave -it to the maintainer to figure out what is the most recent and current -version that should be applied. If there is any doubt, the maintainer -will reply and ask what should be done. - -How do I divide my work into patches? -------------------------------------- -Put yourself in the shoes of the reviewer. Each patch is read separately -and therefore should constitute a comprehensible step towards your stated -goal. +The high volume of development on netdev makes reviewers move on +from discussions relatively quickly. New comments and replies +are very unlikely to arrive after a week of silence. If a patch +is no longer active in patchwork and the thread went idle for more +than a week - clarify the next steps and/or post the next version. -Avoid sending series longer than 15 patches. Larger series takes longer -to review as reviewers will defer looking at it until they find a large -chunk of time. A small series can be reviewed in a short time, so Maintainers -just do it. As a result, a sequence of smaller series gets merged quicker and -with better review coverage. Re-posting large series also increases the mailing -list traffic. +For RFC postings specifically, if nobody responded in a week - reviewers +either missed the posting or have no strong opinions. If the code is ready, +repost as a PATCH. + +Emails saying just "ping" or "bump" are considered rude. If you can't figure +out the status of the patch from patchwork or where the discussion has +landed - describe your best guess and ask if it's correct. For example:: + + I don't understand what the next steps are. Person X seems to be unhappy + with A, should I do B and repost the patches? + +.. _Changes requested: + +Changes requested +~~~~~~~~~~~~~~~~~ -I made changes to only a few patches in a patch series should I resend only those changed? ------------------------------------------------------------------------------------------- -No, please resend the entire patch series and make sure you do number your +Patches :ref:`marked<patch_status>` as ``Changes Requested`` need +to be revised. The new version should come with a change log, +preferably including links to previous postings, for example:: + + [PATCH net-next v3] net: make cows go moo + + Even users who don't drink milk appreciate hearing the cows go "moo". + + The amount of mooing will depend on packet rate so should match + the diurnal cycle quite well. + + Signed-of-by: Joe Defarmer <joe@barn.org> + --- + v3: + - add a note about time-of-day mooing fluctuation to the commit message + v2: https://lore.kernel.org/netdev/123themessageid@barn.org/ + - fix missing argument in kernel doc for netif_is_bovine() + - fix memory leak in netdev_register_cow() + v1: https://lore.kernel.org/netdev/456getstheclicks@barn.org/ + +The commit message should be revised to answer any questions reviewers +had to ask in previous discussions. Occasionally the update of +the commit message will be the only change in the new version. + +Partial resends +~~~~~~~~~~~~~~~ + +Please always resend the entire patch series and make sure you do number your patches such that it is clear this is the latest and greatest set of patches -that can be applied. +that can be applied. Do not try to resend just the patches which changed. -I have received review feedback, when should I post a revised version of the patches? -------------------------------------------------------------------------------------- -Allow at least 24 hours to pass between postings. This will ensure reviewers -from all geographical locations have a chance to chime in. Do not wait -too long (weeks) between postings either as it will make it harder for reviewers -to recall all the context. +Handling misapplied patches +~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Make sure you address all the feedback in your new posting. Do not post a new -version of the code if the discussion about the previous version is still -ongoing, unless directly instructed by a reviewer. +Occasionally a patch series gets applied before receiving critical feedback, +or the wrong version of a series gets applied. -I submitted multiple versions of a patch series and it looks like a version other than the last one has been accepted, what should I do? ----------------------------------------------------------------------------------------------------------------------------------------- -There is no revert possible, once it is pushed out, it stays like that. +Making the patch disappear once it is pushed out is not possible, the commit +history in netdev trees is immutable. Please send incremental versions on top of what has been merged in order to fix the patches the way they would look like if your latest patch series was to be merged. -Are there special rules regarding stable submissions on netdev? ---------------------------------------------------------------- +In cases where full revert is needed the revert has to be submitted +as a patch to the list with a commit message explaining the technical +problems with the reverted commit. Reverts should be used as a last resort, +when original change is completely wrong; incremental fixes are preferred. + +Stable tree +~~~~~~~~~~~ + While it used to be the case that netdev submissions were not supposed to carry explicit ``CC: stable@vger.kernel.org`` tags that is no longer the case today. Please follow the standard stable rules in :ref:`Documentation/process/stable-kernel-rules.rst <stable_kernel_rules>`, and make sure you include appropriate Fixes tags! -Is the comment style convention different for the networking content? ---------------------------------------------------------------------- -Yes, in a largely trivial way. Instead of this:: +Security fixes +~~~~~~~~~~~~~~ + +Do not email netdev maintainers directly if you think you discovered +a bug that might have possible security implications. +The current netdev maintainer has consistently requested that +people use the mailing lists and not reach out directly. If you aren't +OK with that, then perhaps consider mailing security@kernel.org or +reading about http://oss-security.openwall.org/wiki/mailing-lists/distros +as possible alternative mechanisms. + + +Co-posting changes to user space components +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +User space code exercising kernel features should be posted +alongside kernel patches. This gives reviewers a chance to see +how any new interface is used and how well it works. + +When user space tools reside in the kernel repo itself all changes +should generally come as one series. If series becomes too large +or the user space project is not reviewed on netdev include a link +to a public repo where user space patches can be seen. + +In case user space tooling lives in a separate repository but is +reviewed on netdev (e.g. patches to ``iproute2`` tools) kernel and +user space patches should form separate series (threads) when posted +to the mailing list, e.g.:: + + [PATCH net-next 0/3] net: some feature cover letter + └─ [PATCH net-next 1/3] net: some feature prep + └─ [PATCH net-next 2/3] net: some feature do it + └─ [PATCH net-next 3/3] selftest: net: some feature + + [PATCH iproute2-next] ip: add support for some feature + +Posting as one thread is discouraged because it confuses patchwork +(as of patchwork 2.2.2). + +Preparing changes +----------------- + +Attention to detail is important. Re-read your own work as if you were the +reviewer. You can start with using ``checkpatch.pl``, perhaps even with +the ``--strict`` flag. But do not be mindlessly robotic in doing so. +If your change is a bug fix, make sure your commit log indicates the +end-user visible symptom, the underlying reason as to why it happens, +and then if necessary, explain why the fix proposed is the best way to +get things done. Don't mangle whitespace, and as is common, don't +mis-indent function arguments that span multiple lines. If it is your +first patch, mail it to yourself so you can test apply it to an +unpatched tree to confirm infrastructure didn't mangle it. + +Finally, go back and read +:ref:`Documentation/process/submitting-patches.rst <submittingpatches>` +to be sure you are not repeating some common mistake documented there. + +Indicating target tree +~~~~~~~~~~~~~~~~~~~~~~ + +To help maintainers and CI bots you should explicitly mark which tree +your patch is targeting. Assuming that you use git, use the prefix +flag:: + + git format-patch --subject-prefix='PATCH net-next' start..finish + +Use ``net`` instead of ``net-next`` (always lower case) in the above for +bug-fix ``net`` content. + +Dividing work into patches +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Put yourself in the shoes of the reviewer. Each patch is read separately +and therefore should constitute a comprehensible step towards your stated +goal. + +Avoid sending series longer than 15 patches. Larger series takes longer +to review as reviewers will defer looking at it until they find a large +chunk of time. A small series can be reviewed in a short time, so Maintainers +just do it. As a result, a sequence of smaller series gets merged quicker and +with better review coverage. Re-posting large series also increases the mailing +list traffic. + +Multi-line comments +~~~~~~~~~~~~~~~~~~~ + +Comment style convention is slightly different for networking and most of +the tree. Instead of this:: /* * foobar blah blah blah @@ -206,8 +373,8 @@ it is requested that you make it look like this:: * another line of text */ -What is "reverse xmas tree"? ----------------------------- +Local variable ordering ("reverse xmas tree", "RCS") +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Netdev has a convention for ordering local variables in functions. Order the variable declaration lines longest to shortest, e.g.:: @@ -219,21 +386,35 @@ Order the variable declaration lines longest to shortest, e.g.:: If there are dependencies between the variables preventing the ordering move the initialization out of line. -I am working in existing code which uses non-standard formatting. Which formatting should I use? ------------------------------------------------------------------------------------------------- -Make your code follow the most recent guidelines, so that eventually all code +Format precedence +~~~~~~~~~~~~~~~~~ + +When working in existing code which uses nonstandard formatting make +your code follow the most recent guidelines, so that eventually all code in the domain of netdev is in the preferred format. -I found a bug that might have possible security implications or similar. Should I mail the main netdev maintainer off-list? ---------------------------------------------------------------------------------------------------------------------------- -No. The current netdev maintainer has consistently requested that -people use the mailing lists and not reach out directly. If you aren't -OK with that, then perhaps consider mailing security@kernel.org or -reading about http://oss-security.openwall.org/wiki/mailing-lists/distros -as possible alternative mechanisms. +Resending after review +~~~~~~~~~~~~~~~~~~~~~~ + +Allow at least 24 hours to pass between postings. This will ensure reviewers +from all geographical locations have a chance to chime in. Do not wait +too long (weeks) between postings either as it will make it harder for reviewers +to recall all the context. + +Make sure you address all the feedback in your new posting. Do not post a new +version of the code if the discussion about the previous version is still +ongoing, unless directly instructed by a reviewer. + +The new version of patches should be posted as a separate thread, +not as a reply to the previous posting. Change log should include a link +to the previous posting (see :ref:`Changes requested`). + +Testing +------- + +Expected level of testing +~~~~~~~~~~~~~~~~~~~~~~~~~ -What level of testing is expected before I submit my change? ------------------------------------------------------------- At the very minimum your changes must survive an ``allyesconfig`` and an ``allmodconfig`` build with ``W=1`` set without new warnings or failures. @@ -244,78 +425,59 @@ and the patch series contains a set of kernel selftest for You are expected to test your changes on top of the relevant networking tree (``net`` or ``net-next``) and not e.g. a stable tree or ``linux-next``. -How do I post corresponding changes to user space components? -------------------------------------------------------------- -User space code exercising kernel features should be posted -alongside kernel patches. This gives reviewers a chance to see -how any new interface is used and how well it works. - -When user space tools reside in the kernel repo itself all changes -should generally come as one series. If series becomes too large -or the user space project is not reviewed on netdev include a link -to a public repo where user space patches can be seen. - -In case user space tooling lives in a separate repository but is -reviewed on netdev (e.g. patches to ``iproute2`` tools) kernel and -user space patches should form separate series (threads) when posted -to the mailing list, e.g.:: - - [PATCH net-next 0/3] net: some feature cover letter - └─ [PATCH net-next 1/3] net: some feature prep - └─ [PATCH net-next 2/3] net: some feature do it - └─ [PATCH net-next 3/3] selftest: net: some feature - - [PATCH iproute2-next] ip: add support for some feature - -Posting as one thread is discouraged because it confuses patchwork -(as of patchwork 2.2.2). - -Can I reproduce the checks from patchwork on my local machine? --------------------------------------------------------------- +patchwork checks +~~~~~~~~~~~~~~~~ Checks in patchwork are mostly simple wrappers around existing kernel scripts, the sources are available at: -https://github.com/kuba-moo/nipa/tree/master/tests - -Running all the builds and checks locally is a pain, can I post my patches and have the patchwork bot validate them? --------------------------------------------------------------------------------------------------------------------- +https://github.com/linux-netdev/nipa/tree/master/tests -No, you must ensure that your patches are ready by testing them locally +**Do not** post your patches just to run them through the checks. +You must ensure that your patches are ready by testing them locally before posting to the mailing list. The patchwork build bot instance gets overloaded very easily and netdev@vger really doesn't need more traffic if we can help it. -netdevsim is great, can I extend it for my out-of-tree tests? -------------------------------------------------------------- +netdevsim +~~~~~~~~~ -No, ``netdevsim`` is a test vehicle solely for upstream tests. -(Please add your tests under ``tools/testing/selftests/``.) +``netdevsim`` is a test driver which can be used to exercise driver +configuration APIs without requiring capable hardware. +Mock-ups and tests based on ``netdevsim`` are strongly encouraged when +adding new APIs, but ``netdevsim`` in itself is **not** considered +a use case/user. You must also implement the new APIs in a real driver. -We also give no guarantees that ``netdevsim`` won't change in the future +We give no guarantees that ``netdevsim`` won't change in the future in a way which would break what would normally be considered uAPI. -Is netdevsim considered a "user" of an API? -------------------------------------------- +``netdevsim`` is reserved for use by upstream tests only, so any +new ``netdevsim`` features must be accompanied by selftests under +``tools/testing/selftests/``. -Linux kernel has a long standing rule that no API should be added unless -it has a real, in-tree user. Mock-ups and tests based on ``netdevsim`` are -strongly encouraged when adding new APIs, but ``netdevsim`` in itself -is **not** considered a use case/user. +Reviewer guidance +----------------- -Any other tips to help ensure my net/net-next patch gets OK'd? --------------------------------------------------------------- -Attention to detail. Re-read your own work as if you were the -reviewer. You can start with using ``checkpatch.pl``, perhaps even with -the ``--strict`` flag. But do not be mindlessly robotic in doing so. -If your change is a bug fix, make sure your commit log indicates the -end-user visible symptom, the underlying reason as to why it happens, -and then if necessary, explain why the fix proposed is the best way to -get things done. Don't mangle whitespace, and as is common, don't -mis-indent function arguments that span multiple lines. If it is your -first patch, mail it to yourself so you can test apply it to an -unpatched tree to confirm infrastructure didn't mangle it. +Reviewing other people's patches on the list is highly encouraged, +regardless of the level of expertise. For general guidance and +helpful tips please see :ref:`development_advancedtopics_reviews`. -Finally, go back and read -:ref:`Documentation/process/submitting-patches.rst <submittingpatches>` -to be sure you are not repeating some common mistake documented there. +It's safe to assume that netdev maintainers know the community and the level +of expertise of the reviewers. The reviewers should not be concerned about +their comments impeding or derailing the patch flow. + +Less experienced reviewers are highly encouraged to do more in-depth +review of submissions and not focus exclusively on trivial or subjective +matters like code formatting, tags etc. + +Testimonials / feedback +----------------------- + +Some companies use peer feedback in employee performance reviews. +Please feel free to request feedback from netdev maintainers, +especially if you spend significant amount of time reviewing code +and go out of your way to improve shared infrastructure. + +The feedback must be requested by you, the contributor, and will always +be shared with you (even if you request for it to be submitted to your +manager). |