1 2Information you need to know about netdev 3----------------------------------------- 4 5Q: What is netdev? 6 7A: It is a mailing list for all network-related Linux stuff. This includes 8 anything found under net/ (i.e. core code like IPv6) and drivers/net 9 (i.e. hardware specific drivers) in the Linux source tree. 10 11 Note that some subsystems (e.g. wireless drivers) which have a high volume 12 of traffic have their own specific mailing lists. 13 14 The netdev list is managed (like many other Linux mailing lists) through 15 VGER ( http://vger.kernel.org/ ) and archives can be found below: 16 17 http://marc.info/?l=linux-netdev 18 http://www.spinics.net/lists/netdev/ 19 20 Aside from subsystems like that mentioned above, all network-related Linux 21 development (i.e. RFC, review, comments, etc.) takes place on netdev. 22 23Q: How do the changes posted to netdev make their way into Linux? 24 25A: There are always two trees (git repositories) in play. Both are driven 26 by David Miller, the main network maintainer. There is the "net" tree, 27 and the "net-next" tree. As you can probably guess from the names, the 28 net tree is for fixes to existing code already in the mainline tree from 29 Linus, and net-next is where the new code goes for the future release. 30 You can find the trees here: 31 32 https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git 33 https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 34 35Q: How often do changes from these trees make it to the mainline Linus tree? 36 37A: To understand this, you need to know a bit of background information 38 on the cadence of Linux development. Each new release starts off with 39 a two week "merge window" where the main maintainers feed their new 40 stuff to Linus for merging into the mainline tree. After the two weeks, 41 the merge window is closed, and it is called/tagged "-rc1". No new 42 features get mainlined after this -- only fixes to the rc1 content 43 are expected. After roughly a week of collecting fixes to the rc1 44 content, rc2 is released. This repeats on a roughly weekly basis 45 until rc7 (typically; sometimes rc6 if things are quiet, or rc8 if 46 things are in a state of churn), and a week after the last vX.Y-rcN 47 was done, the official "vX.Y" is released. 48 49 Relating that to netdev: At the beginning of the 2-week merge window, 50 the net-next tree will be closed - no new changes/features. The 51 accumulated new content of the past ~10 weeks will be passed onto 52 mainline/Linus via a pull request for vX.Y -- at the same time, 53 the "net" tree will start accumulating fixes for this pulled content 54 relating to vX.Y 55 56 An announcement indicating when net-next has been closed is usually 57 sent to netdev, but knowing the above, you can predict that in advance. 58 59 IMPORTANT: Do not send new net-next content to netdev during the 60 period during which net-next tree is closed. 61 62 Shortly after the two weeks have passed (and vX.Y-rc1 is released), the 63 tree for net-next reopens to collect content for the next (vX.Y+1) release. 64 65 If you aren't subscribed to netdev and/or are simply unsure if net-next 66 has re-opened yet, simply check the net-next git repository link above for 67 any new networking-related commits. 68 69 The "net" tree continues to collect fixes for the vX.Y content, and 70 is fed back to Linus at regular (~weekly) intervals. Meaning that the 71 focus for "net" is on stabilization and bugfixes. 72 73 Finally, the vX.Y gets released, and the whole cycle starts over. 74 75Q: So where are we now in this cycle? 76 77A: Load the mainline (Linus) page here: 78 79 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 80 81 and note the top of the "tags" section. If it is rc1, it is early 82 in the dev cycle. If it was tagged rc7 a week ago, then a release 83 is probably imminent. 84 85Q: How do I indicate which tree (net vs. net-next) my patch should be in? 86 87A: Firstly, think whether you have a bug fix or new "next-like" content. 88 Then once decided, assuming that you use git, use the prefix flag, i.e. 89 90 git format-patch --subject-prefix='PATCH net-next' start..finish 91 92 Use "net" instead of "net-next" (always lower case) in the above for 93 bug-fix net content. If you don't use git, then note the only magic in 94 the above is just the subject text of the outgoing e-mail, and you can 95 manually change it yourself with whatever MUA you are comfortable with. 96 97Q: I sent a patch and I'm wondering what happened to it. How can I tell 98 whether it got merged? 99 100A: Start by looking at the main patchworks queue for netdev: 101 102 http://patchwork.ozlabs.org/project/netdev/list/ 103 104 The "State" field will tell you exactly where things are at with 105 your patch. 106 107Q: The above only says "Under Review". How can I find out more? 108 109A: Generally speaking, the patches get triaged quickly (in less than 48h). 110 So be patient. Asking the maintainer for status updates on your 111 patch is a good way to ensure your patch is ignored or pushed to 112 the bottom of the priority list. 113 114Q: I submitted multiple versions of the patch series, should I directly update 115 patchwork for the previous versions of these patch series? 116 117A: No, please don't interfere with the patch status on patchwork, leave it to 118 the maintainer to figure out what is the most recent and current version that 119 should be applied. If there is any doubt, the maintainer will reply and ask 120 what should be done. 121 122Q: How can I tell what patches are queued up for backporting to the 123 various stable releases? 124 125A: Normally Greg Kroah-Hartman collects stable commits himself, but 126 for networking, Dave collects up patches he deems critical for the 127 networking subsystem, and then hands them off to Greg. 128 129 There is a patchworks queue that you can see here: 130 http://patchwork.ozlabs.org/bundle/davem/stable/?state=* 131 132 It contains the patches which Dave has selected, but not yet handed 133 off to Greg. If Greg already has the patch, then it will be here: 134 https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git 135 136 A quick way to find whether the patch is in this stable-queue is 137 to simply clone the repo, and then git grep the mainline commit ID, e.g. 138 139 stable-queue$ git grep -l 284041ef21fdf2e 140 releases/3.0.84/ipv6-fix-possible-crashes-in-ip6_cork_release.patch 141 releases/3.4.51/ipv6-fix-possible-crashes-in-ip6_cork_release.patch 142 releases/3.9.8/ipv6-fix-possible-crashes-in-ip6_cork_release.patch 143 stable/stable-queue$ 144 145Q: I see a network patch and I think it should be backported to stable. 146 Should I request it via "stable@vger.kernel.org" like the references in 147 the kernel's Documentation/process/stable-kernel-rules.rst file say? 148 149A: No, not for networking. Check the stable queues as per above 1st to see 150 if it is already queued. If not, then send a mail to netdev, listing 151 the upstream commit ID and why you think it should be a stable candidate. 152 153 Before you jump to go do the above, do note that the normal stable rules 154 in Documentation/process/stable-kernel-rules.rst still apply. So you need to 155 explicitly indicate why it is a critical fix and exactly what users are 156 impacted. In addition, you need to convince yourself that you _really_ 157 think it has been overlooked, vs. having been considered and rejected. 158 159 Generally speaking, the longer it has had a chance to "soak" in mainline, 160 the better the odds that it is an OK candidate for stable. So scrambling 161 to request a commit be added the day after it appears should be avoided. 162 163Q: I have created a network patch and I think it should be backported to 164 stable. Should I add a "Cc: stable@vger.kernel.org" like the references 165 in the kernel's Documentation/ directory say? 166 167A: No. See above answer. In short, if you think it really belongs in 168 stable, then ensure you write a decent commit log that describes who 169 gets impacted by the bugfix and how it manifests itself, and when the 170 bug was introduced. If you do that properly, then the commit will 171 get handled appropriately and most likely get put in the patchworks 172 stable queue if it really warrants it. 173 174 If you think there is some valid information relating to it being in 175 stable that does _not_ belong in the commit log, then use the three 176 dash marker line as described in Documentation/process/submitting-patches.rst to 177 temporarily embed that information into the patch that you send. 178 179Q: Are all networking bug fixes backported to all stable releases? 180 181A: Due to capacity, Dave could only take care of the backports for the last 182 2 stable releases. For earlier stable releases, each stable branch maintainer 183 is supposed to take care of them. If you find any patch is missing from an 184 earlier stable branch, please notify stable@vger.kernel.org with either a 185 commit ID or a formal patch backported, and CC Dave and other relevant 186 networking developers. 187 188Q: Someone said that the comment style and coding convention is different 189 for the networking content. Is this true? 190 191A: Yes, in a largely trivial way. Instead of this: 192 193 /* 194 * foobar blah blah blah 195 * another line of text 196 */ 197 198 it is requested that you make it look like this: 199 200 /* foobar blah blah blah 201 * another line of text 202 */ 203 204Q: I am working in existing code that has the former comment style and not the 205 latter. Should I submit new code in the former style or the latter? 206 207A: Make it the latter style, so that eventually all code in the domain of 208 netdev is of this format. 209 210Q: I found a bug that might have possible security implications or similar. 211 Should I mail the main netdev maintainer off-list? 212 213A: No. The current netdev maintainer has consistently requested that people 214 use the mailing lists and not reach out directly. If you aren't OK with 215 that, then perhaps consider mailing "security@kernel.org" or reading about 216 http://oss-security.openwall.org/wiki/mailing-lists/distros 217 as possible alternative mechanisms. 218 219Q: What level of testing is expected before I submit my change? 220 221A: If your changes are against net-next, the expectation is that you 222 have tested by layering your changes on top of net-next. Ideally you 223 will have done run-time testing specific to your change, but at a 224 minimum, your changes should survive an "allyesconfig" and an 225 "allmodconfig" build without new warnings or failures. 226 227Q: Any other tips to help ensure my net/net-next patch gets OK'd? 228 229A: Attention to detail. Re-read your own work as if you were the 230 reviewer. You can start with using checkpatch.pl, perhaps even 231 with the "--strict" flag. But do not be mindlessly robotic in 232 doing so. If your change is a bug-fix, make sure your commit log 233 indicates the end-user visible symptom, the underlying reason as 234 to why it happens, and then if necessary, explain why the fix proposed 235 is the best way to get things done. Don't mangle whitespace, and as 236 is common, don't mis-indent function arguments that span multiple lines. 237 If it is your first patch, mail it to yourself so you can test apply 238 it to an unpatched tree to confirm infrastructure didn't mangle it. 239 240 Finally, go back and read Documentation/process/submitting-patches.rst to be 241 sure you are not repeating some common mistake documented there. 242