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2 Information you need to know about netdev
3 -----------------------------------------
5 Q: What is netdev?
7 A: 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.
11 Note that some subsystems (e.g. wireless drivers) which have a high volume
12 of traffic have their own specific mailing lists.
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:
17 http://marc.info/?l=linux-netdev
18 http://www.spinics.net/lists/netdev/
20 Aside from subsystems like that mentioned above, all network-related Linux
21 development (i.e. RFC, review, comments, etc.) takes place on netdev.
23 Q: How do the changes posted to netdev make their way into Linux?
25 A: 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:
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
35 Q: How often do changes from these trees make it to the mainline Linus tree?
37 A: 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.
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
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.
59 IMPORTANT: Do not send new net-next content to netdev during the
60 period during which net-next tree is closed.
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.
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.
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.
73 Finally, the vX.Y gets released, and the whole cycle starts over.
75 Q: So where are we now in this cycle?
77 A: Load the mainline (Linus) page here:
79 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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.
85 Q: How do I indicate which tree (net vs. net-next) my patch should be in?
87 A: 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.
90 git format-patch --subject-prefix='PATCH net-next' start..finish
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.
97 Q: I sent a patch and I'm wondering what happened to it. How can I tell
98 whether it got merged?
100 A: Start by looking at the main patchworks queue for netdev:
102 http://patchwork.ozlabs.org/project/netdev/list/
104 The "State" field will tell you exactly where things are at with
105 your patch.
107 Q: The above only says "Under Review". How can I find out more?
109 A: 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.
114 Q: How can I tell what patches are queued up for backporting to the
115 various stable releases?
117 A: Normally Greg Kroah-Hartman collects stable commits himself, but
118 for networking, Dave collects up patches he deems critical for the
119 networking subsystem, and then hands them off to Greg.
121 There is a patchworks queue that you can see here:
122 http://patchwork.ozlabs.org/bundle/davem/stable/?state=*
124 It contains the patches which Dave has selected, but not yet handed
125 off to Greg. If Greg already has the patch, then it will be here:
126 https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git
128 A quick way to find whether the patch is in this stable-queue is
129 to simply clone the repo, and then git grep the mainline commit ID, e.g.
131 stable-queue$ git grep -l 284041ef21fdf2e
132 releases/3.0.84/ipv6-fix-possible-crashes-in-ip6_cork_release.patch
133 releases/3.4.51/ipv6-fix-possible-crashes-in-ip6_cork_release.patch
134 releases/3.9.8/ipv6-fix-possible-crashes-in-ip6_cork_release.patch
135 stable/stable-queue$
137 Q: I see a network patch and I think it should be backported to stable.
138 Should I request it via "stable@vger.kernel.org" like the references in
139 the kernel's Documentation/stable_kernel_rules.txt file say?
141 A: No, not for networking. Check the stable queues as per above 1st to see
142 if it is already queued. If not, then send a mail to netdev, listing
143 the upstream commit ID and why you think it should be a stable candidate.
145 Before you jump to go do the above, do note that the normal stable rules
146 in Documentation/stable_kernel_rules.txt still apply. So you need to
147 explicitly indicate why it is a critical fix and exactly what users are
148 impacted. In addition, you need to convince yourself that you _really_
149 think it has been overlooked, vs. having been considered and rejected.
151 Generally speaking, the longer it has had a chance to "soak" in mainline,
152 the better the odds that it is an OK candidate for stable. So scrambling
153 to request a commit be added the day after it appears should be avoided.
155 Q: I have created a network patch and I think it should be backported to
156 stable. Should I add a "Cc: stable@vger.kernel.org" like the references
157 in the kernel's Documentation/ directory say?
159 A: No. See above answer. In short, if you think it really belongs in
160 stable, then ensure you write a decent commit log that describes who
161 gets impacted by the bugfix and how it manifests itself, and when the
162 bug was introduced. If you do that properly, then the commit will
163 get handled appropriately and most likely get put in the patchworks
164 stable queue if it really warrants it.
166 If you think there is some valid information relating to it being in
167 stable that does _not_ belong in the commit log, then use the three
168 dash marker line as described in Documentation/SubmittingPatches to
169 temporarily embed that information into the patch that you send.
171 Q: Someone said that the comment style and coding convention is different
172 for the networking content. Is this true?
174 A: Yes, in a largely trivial way. Instead of this:
176 /*
177 * foobar blah blah blah
178 * another line of text
179 */
181 it is requested that you make it look like this:
183 /* foobar blah blah blah
184 * another line of text
185 */
187 Q: I am working in existing code that has the former comment style and not the
188 latter. Should I submit new code in the former style or the latter?
190 A: Make it the latter style, so that eventually all code in the domain of
191 netdev is of this format.
193 Q: I found a bug that might have possible security implications or similar.
194 Should I mail the main netdev maintainer off-list?
196 A: No. The current netdev maintainer has consistently requested that people
197 use the mailing lists and not reach out directly. If you aren't OK with
198 that, then perhaps consider mailing "security@kernel.org" or reading about
199 http://oss-security.openwall.org/wiki/mailing-lists/distros
200 as possible alternative mechanisms.
202 Q: What level of testing is expected before I submit my change?
204 A: If your changes are against net-next, the expectation is that you
205 have tested by layering your changes on top of net-next. Ideally you
206 will have done run-time testing specific to your change, but at a
207 minimum, your changes should survive an "allyesconfig" and an
208 "allmodconfig" build without new warnings or failures.
210 Q: Any other tips to help ensure my net/net-next patch gets OK'd?
212 A: Attention to detail. Re-read your own work as if you were the
213 reviewer. You can start with using checkpatch.pl, perhaps even
214 with the "--strict" flag. But do not be mindlessly robotic in
215 doing so. If your change is a bug-fix, make sure your commit log
216 indicates the end-user visible symptom, the underlying reason as
217 to why it happens, and then if necessary, explain why the fix proposed
218 is the best way to get things done. Don't mangle whitespace, and as
219 is common, don't mis-indent function arguments that span multiple lines.
220 If it is your first patch, mail it to yourself so you can test apply
221 it to an unpatched tree to confirm infrastructure didn't mangle it.
223 Finally, go back and read Documentation/SubmittingPatches to be
224 sure you are not repeating some common mistake documented there.