1.. SPDX-License-Identifier: GPL-2.0 2 3.. _netdev-FAQ: 4 5========== 6netdev FAQ 7========== 8 9What is netdev? 10--------------- 11It is a mailing list for all network-related Linux stuff. This 12includes anything found under net/ (i.e. core code like IPv6) and 13drivers/net (i.e. hardware specific drivers) in the Linux source tree. 14 15Note that some subsystems (e.g. wireless drivers) which have a high 16volume of traffic have their own specific mailing lists. 17 18The netdev list is managed (like many other Linux mailing lists) through 19VGER (http://vger.kernel.org/) and archives can be found below: 20 21- http://marc.info/?l=linux-netdev 22- http://www.spinics.net/lists/netdev/ 23 24Aside from subsystems like that mentioned above, all network-related 25Linux development (i.e. RFC, review, comments, etc.) takes place on 26netdev. 27 28How do the changes posted to netdev make their way into Linux? 29-------------------------------------------------------------- 30There are always two trees (git repositories) in play. Both are 31driven by David Miller, the main network maintainer. There is the 32``net`` tree, and the ``net-next`` tree. As you can probably guess from 33the names, the ``net`` tree is for fixes to existing code already in the 34mainline tree from Linus, and ``net-next`` is where the new code goes 35for the future release. You can find the trees here: 36 37- https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git 38- https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git 39 40How often do changes from these trees make it to the mainline Linus tree? 41------------------------------------------------------------------------- 42To understand this, you need to know a bit of background information on 43the cadence of Linux development. Each new release starts off with a 44two week "merge window" where the main maintainers feed their new stuff 45to Linus for merging into the mainline tree. After the two weeks, the 46merge window is closed, and it is called/tagged ``-rc1``. No new 47features get mainlined after this -- only fixes to the rc1 content are 48expected. After roughly a week of collecting fixes to the rc1 content, 49rc2 is released. This repeats on a roughly weekly basis until rc7 50(typically; sometimes rc6 if things are quiet, or rc8 if things are in a 51state of churn), and a week after the last vX.Y-rcN was done, the 52official vX.Y is released. 53 54Relating that to netdev: At the beginning of the 2-week merge window, 55the ``net-next`` tree will be closed - no new changes/features. The 56accumulated new content of the past ~10 weeks will be passed onto 57mainline/Linus via a pull request for vX.Y -- at the same time, the 58``net`` tree will start accumulating fixes for this pulled content 59relating to vX.Y 60 61An announcement indicating when ``net-next`` has been closed is usually 62sent to netdev, but knowing the above, you can predict that in advance. 63 64IMPORTANT: Do not send new ``net-next`` content to netdev during the 65period during which ``net-next`` tree is closed. 66 67Shortly after the two weeks have passed (and vX.Y-rc1 is released), the 68tree for ``net-next`` reopens to collect content for the next (vX.Y+1) 69release. 70 71If you aren't subscribed to netdev and/or are simply unsure if 72``net-next`` has re-opened yet, simply check the ``net-next`` git 73repository link above for any new networking-related commits. You may 74also check the following website for the current status: 75 76 http://vger.kernel.org/~davem/net-next.html 77 78The ``net`` tree continues to collect fixes for the vX.Y content, and is 79fed back to Linus at regular (~weekly) intervals. Meaning that the 80focus for ``net`` is on stabilization and bug fixes. 81 82Finally, the vX.Y gets released, and the whole cycle starts over. 83 84So where are we now in this cycle? 85---------------------------------- 86 87Load the mainline (Linus) page here: 88 89 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 90 91and note the top of the "tags" section. If it is rc1, it is early in 92the dev cycle. If it was tagged rc7 a week ago, then a release is 93probably imminent. 94 95How do I indicate which tree (net vs. net-next) my patch should be in? 96---------------------------------------------------------------------- 97Firstly, think whether you have a bug fix or new "next-like" content. 98Then once decided, assuming that you use git, use the prefix flag, i.e. 99:: 100 101 git format-patch --subject-prefix='PATCH net-next' start..finish 102 103Use ``net`` instead of ``net-next`` (always lower case) in the above for 104bug-fix ``net`` content. If you don't use git, then note the only magic 105in the above is just the subject text of the outgoing e-mail, and you 106can manually change it yourself with whatever MUA you are comfortable 107with. 108 109I sent a patch and I'm wondering what happened to it - how can I tell whether it got merged? 110-------------------------------------------------------------------------------------------- 111Start by looking at the main patchworks queue for netdev: 112 113 https://patchwork.kernel.org/project/netdevbpf/list/ 114 115The "State" field will tell you exactly where things are at with your 116patch. 117 118The above only says "Under Review". How can I find out more? 119------------------------------------------------------------- 120Generally speaking, the patches get triaged quickly (in less than 12148h). So be patient. Asking the maintainer for status updates on your 122patch is a good way to ensure your patch is ignored or pushed to the 123bottom of the priority list. 124 125I submitted multiple versions of the patch series. Should I directly update patchwork for the previous versions of these patch series? 126-------------------------------------------------------------------------------------------------------------------------------------- 127No, please don't interfere with the patch status on patchwork, leave 128it to the maintainer to figure out what is the most recent and current 129version that should be applied. If there is any doubt, the maintainer 130will reply and ask what should be done. 131 132I made changes to only a few patches in a patch series should I resend only those changed? 133------------------------------------------------------------------------------------------ 134No, please resend the entire patch series and make sure you do number your 135patches such that it is clear this is the latest and greatest set of patches 136that can be applied. 137 138I 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? 139---------------------------------------------------------------------------------------------------------------------------------------- 140There is no revert possible, once it is pushed out, it stays like that. 141Please send incremental versions on top of what has been merged in order to fix 142the patches the way they would look like if your latest patch series was to be 143merged. 144 145Are there special rules regarding stable submissions on netdev? 146--------------------------------------------------------------- 147While it used to be the case that netdev submissions were not supposed 148to carry explicit ``CC: stable@vger.kernel.org`` tags that is no longer 149the case today. Please follow the standard stable rules in 150:ref:`Documentation/process/stable-kernel-rules.rst <stable_kernel_rules>`, 151and make sure you include appropriate Fixes tags! 152 153Is the comment style convention different for the networking content? 154--------------------------------------------------------------------- 155Yes, in a largely trivial way. Instead of this:: 156 157 /* 158 * foobar blah blah blah 159 * another line of text 160 */ 161 162it is requested that you make it look like this:: 163 164 /* foobar blah blah blah 165 * another line of text 166 */ 167 168I am working in existing code that has the former comment style and not the latter. Should I submit new code in the former style or the latter? 169----------------------------------------------------------------------------------------------------------------------------------------------- 170Make it the latter style, so that eventually all code in the domain 171of netdev is of this format. 172 173I found a bug that might have possible security implications or similar. Should I mail the main netdev maintainer off-list? 174--------------------------------------------------------------------------------------------------------------------------- 175No. The current netdev maintainer has consistently requested that 176people use the mailing lists and not reach out directly. If you aren't 177OK with that, then perhaps consider mailing security@kernel.org or 178reading about http://oss-security.openwall.org/wiki/mailing-lists/distros 179as possible alternative mechanisms. 180 181What level of testing is expected before I submit my change? 182------------------------------------------------------------ 183If your changes are against ``net-next``, the expectation is that you 184have tested by layering your changes on top of ``net-next``. Ideally 185you will have done run-time testing specific to your change, but at a 186minimum, your changes should survive an ``allyesconfig`` and an 187``allmodconfig`` build without new warnings or failures. 188 189How do I post corresponding changes to user space components? 190------------------------------------------------------------- 191User space code exercising kernel features should be posted 192alongside kernel patches. This gives reviewers a chance to see 193how any new interface is used and how well it works. 194 195When user space tools reside in the kernel repo itself all changes 196should generally come as one series. If series becomes too large 197or the user space project is not reviewed on netdev include a link 198to a public repo where user space patches can be seen. 199 200In case user space tooling lives in a separate repository but is 201reviewed on netdev (e.g. patches to `iproute2` tools) kernel and 202user space patches should form separate series (threads) when posted 203to the mailing list, e.g.:: 204 205 [PATCH net-next 0/3] net: some feature cover letter 206 └─ [PATCH net-next 1/3] net: some feature prep 207 └─ [PATCH net-next 2/3] net: some feature do it 208 └─ [PATCH net-next 3/3] selftest: net: some feature 209 210 [PATCH iproute2-next] ip: add support for some feature 211 212Posting as one thread is discouraged because it confuses patchwork 213(as of patchwork 2.2.2). 214 215Can I reproduce the checks from patchwork on my local machine? 216-------------------------------------------------------------- 217 218Checks in patchwork are mostly simple wrappers around existing kernel 219scripts, the sources are available at: 220 221https://github.com/kuba-moo/nipa/tree/master/tests 222 223Running all the builds and checks locally is a pain, can I post my patches and have the patchwork bot validate them? 224-------------------------------------------------------------------------------------------------------------------- 225 226No, you must ensure that your patches are ready by testing them locally 227before posting to the mailing list. The patchwork build bot instance 228gets overloaded very easily and netdev@vger really doesn't need more 229traffic if we can help it. 230 231netdevsim is great, can I extend it for my out-of-tree tests? 232------------------------------------------------------------- 233 234No, `netdevsim` is a test vehicle solely for upstream tests. 235(Please add your tests under tools/testing/selftests/.) 236 237We also give no guarantees that `netdevsim` won't change in the future 238in a way which would break what would normally be considered uAPI. 239 240Is netdevsim considered a "user" of an API? 241------------------------------------------- 242 243Linux kernel has a long standing rule that no API should be added unless 244it has a real, in-tree user. Mock-ups and tests based on `netdevsim` are 245strongly encouraged when adding new APIs, but `netdevsim` in itself 246is **not** considered a use case/user. 247 248Any other tips to help ensure my net/net-next patch gets OK'd? 249-------------------------------------------------------------- 250Attention to detail. Re-read your own work as if you were the 251reviewer. You can start with using ``checkpatch.pl``, perhaps even with 252the ``--strict`` flag. But do not be mindlessly robotic in doing so. 253If your change is a bug fix, make sure your commit log indicates the 254end-user visible symptom, the underlying reason as to why it happens, 255and then if necessary, explain why the fix proposed is the best way to 256get things done. Don't mangle whitespace, and as is common, don't 257mis-indent function arguments that span multiple lines. If it is your 258first patch, mail it to yourself so you can test apply it to an 259unpatched tree to confirm infrastructure didn't mangle it. 260 261Finally, go back and read 262:ref:`Documentation/process/submitting-patches.rst <submittingpatches>` 263to be sure you are not repeating some common mistake documented there. 264