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diff --git a/Documentation/networking/netdev-FAQ.rst b/Documentation/networking/netdev-FAQ.rst new file mode 100644 index 000000000..0ac5fa77f --- /dev/null +++ b/Documentation/networking/netdev-FAQ.rst @@ -0,0 +1,259 @@ +.. SPDX-License-Identifier: GPL-2.0 + +.. _netdev-FAQ: + +========== +netdev FAQ +========== + +Q: What is netdev? +------------------ +A: It 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. + +The netdev list is managed (like many other Linux mailing lists) through +VGER (http://vger.kernel.org/) and archives can be found below: + +- http://marc.info/?l=linux-netdev +- http://www.spinics.net/lists/netdev/ + +Aside from subsystems like that mentioned above, all network-related +Linux development (i.e. RFC, review, comments, etc.) takes place on +netdev. + +Q: How do the changes posted to netdev make their way into Linux? +----------------------------------------------------------------- +A: 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/davem/net.git +- https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git + +Q: How often do changes from these trees make it to the mainline Linus tree? +---------------------------------------------------------------------------- +A: To understand this, you need to know 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 +merge window is closed, and it is called/tagged ``-rc1``. No new +features get mainlined after this -- only fixes to the rc1 content are +expected. After roughly a week of collecting fixes to the rc1 content, +rc2 is released. This repeats on a roughly weekly basis until rc7 +(typically; sometimes rc6 if things are quiet, or rc8 if things are in a +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 +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 + +An announcement indicating when ``net-next`` has been closed is usually +sent to netdev, but knowing the above, you can predict that in advance. + +IMPORTANT: Do not send new ``net-next`` content to netdev during the +period during which ``net-next`` tree is closed. + +Shortly after the two weeks have passed (and vX.Y-rc1 is released), the +tree for ``net-next`` reopens to collect content for the next (vX.Y+1) +release. + +If you aren't subscribed to netdev and/or are simply unsure if +``net-next`` has re-opened yet, simply check the ``net-next`` git +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 + +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 +focus for ``net`` is on stabilization and bug fixes. + +Finally, the vX.Y gets released, and the whole cycle starts over. + +Q: So where are we now in this 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. + +Q: How do I indicate which tree (net vs. net-next) my patch should be in? +------------------------------------------------------------------------- +A: Firstly, think whether you have a bug fix or new "next-like" content. +Then once decided, assuming that you use git, use the prefix flag, i.e. +:: + + 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. If you don't use git, then note the only magic +in the above is just the subject text of the outgoing e-mail, and you +can manually change it yourself with whatever MUA you are comfortable +with. + +Q: I sent a patch and I'm wondering what happened to it? +-------------------------------------------------------- +Q: How can I tell whether it got merged? +A: Start by looking at the main patchworks queue for netdev: + + http://patchwork.ozlabs.org/project/netdev/list/ + +The "State" field will tell you exactly where things are at with your +patch. + +Q: The above only says "Under Review". How can I find out more? +---------------------------------------------------------------- +A: Generally speaking, the patches get triaged quickly (in less than +48h). So be patient. 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. + +Q: I submitted multiple versions of the patch series +---------------------------------------------------- +Q: should I directly update patchwork for the previous versions of these +patch series? +A: No, please don't interfere with the patch status on patchwork, 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. + +Q: How can I tell what patches are queued up for backporting to the various stable releases? +-------------------------------------------------------------------------------------------- +A: Normally Greg Kroah-Hartman collects stable commits himself, but for +networking, Dave collects up patches he deems critical for the +networking subsystem, and then hands them off to Greg. + +There is a patchworks queue that you can see here: + + http://patchwork.ozlabs.org/bundle/davem/stable/?state=* + +It contains the patches which Dave has selected, but not yet handed off +to Greg. If Greg already has the patch, then it will be here: + + https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git + +A quick way to find whether the patch is in this stable-queue is to +simply clone the repo, and then git grep the mainline commit ID, e.g. +:: + + stable-queue$ git grep -l 284041ef21fdf2e + releases/3.0.84/ipv6-fix-possible-crashes-in-ip6_cork_release.patch + releases/3.4.51/ipv6-fix-possible-crashes-in-ip6_cork_release.patch + releases/3.9.8/ipv6-fix-possible-crashes-in-ip6_cork_release.patch + stable/stable-queue$ + +Q: I see a network patch and I think it should be backported to stable. +----------------------------------------------------------------------- +Q: Should I request it via stable@vger.kernel.org like the references in +the kernel's Documentation/process/stable-kernel-rules.rst file say? +A: No, not for networking. Check the stable queues as per above first +to see if it is already queued. If not, then send a mail to netdev, +listing the upstream commit ID and why you think it should be a stable +candidate. + +Before you jump to go do the above, do note that the normal stable rules +in :ref:`Documentation/process/stable-kernel-rules.rst <stable_kernel_rules>` +still apply. So you need to explicitly indicate why it is a critical +fix and exactly what users are impacted. In addition, you need to +convince yourself that you *really* think it has been overlooked, +vs. having been considered and rejected. + +Generally speaking, the longer it has had a chance to "soak" in +mainline, the better the odds that it is an OK candidate for stable. So +scrambling to request a commit be added the day after it appears should +be avoided. + +Q: I have created a network patch and I think it should be backported to stable. +-------------------------------------------------------------------------------- +Q: Should I add a Cc: stable@vger.kernel.org like the references in the +kernel's Documentation/ directory say? +A: No. See above answer. In short, if you think it really belongs in +stable, then ensure you write a decent commit log that describes who +gets impacted by the bug fix and how it manifests itself, and when the +bug was introduced. If you do that properly, then the commit will get +handled appropriately and most likely get put in the patchworks stable +queue if it really warrants it. + +If you think there is some valid information relating to it being in +stable that does *not* belong in the commit log, then use the three dash +marker line as described in +:ref:`Documentation/process/submitting-patches.rst <the_canonical_patch_format>` +to temporarily embed that information into the patch that you send. + +Q: Are all networking bug fixes backported to all stable releases? +------------------------------------------------------------------ +A: Due to capacity, Dave could only take care of the backports for the +last two stable releases. For earlier stable releases, each stable +branch maintainer is supposed to take care of them. If you find any +patch is missing from an earlier stable branch, please notify +stable@vger.kernel.org with either a commit ID or a formal patch +backported, and CC Dave and other relevant networking developers. + +Q: Is the comment style convention different for the networking content? +------------------------------------------------------------------------ +A: Yes, in a largely trivial way. Instead of this:: + + /* + * foobar blah blah blah + * another line of text + */ + +it is requested that you make it look like this:: + + /* foobar blah blah blah + * another line of text + */ + +Q: I am working in existing code that has the former comment style and not the latter. +-------------------------------------------------------------------------------------- +Q: Should I submit new code in the former style or the latter? +A: Make it the latter style, so that eventually all code in the domain +of netdev is of this format. + +Q: I found a bug that might have possible security implications or similar. +--------------------------------------------------------------------------- +Q: Should I mail the main netdev maintainer off-list?** +A: 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. + +Q: What level of testing is expected before I submit my change? +--------------------------------------------------------------- +A: If your changes are against ``net-next``, the expectation is that you +have tested by layering your changes on top of ``net-next``. Ideally +you will have done run-time testing specific to your change, but at a +minimum, your changes should survive an ``allyesconfig`` and an +``allmodconfig`` build without new warnings or failures. + +Q: Any other tips to help ensure my net/net-next patch gets OK'd? +----------------------------------------------------------------- +A: 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. + +Finally, go back and read +:ref:`Documentation/process/submitting-patches.rst <submittingpatches>` +to be sure you are not repeating some common mistake documented there. |