From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Gortmaker Subject: Re: [RFC] Any value in having a netdev FAQ? Date: Wed, 17 Jul 2013 11:18:22 -0400 Message-ID: <51E6B5BE.6050505@windriver.com> References: <20130716025954.GC26761@windriver.com> <1374006725.12825.112.camel@envy.home> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: "David S. Miller" , Greg Kroah-Hartman , To: Darren Hart Return-path: Received: from mail.windriver.com ([147.11.1.11]:54606 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752053Ab3GQPST (ORCPT ); Wed, 17 Jul 2013 11:18:19 -0400 In-Reply-To: <1374006725.12825.112.camel@envy.home> Sender: netdev-owner@vger.kernel.org List-ID: On 13-07-16 04:32 PM, Darren Hart wrote: > On Mon, 2013-07-15 at 22:59 -0400, Paul Gortmaker wrote: >> Hi Dave, >> >> I was wondering if you think there is value in having a netdev-faq type >> document available -- perhaps as a vger mailout to new subscribers or >> similar? For example, I have lost count of the number of times that you >> have had to tell people that net-next is closed during the merge window. >> But you would probably be right in telling me that those same people don't >> read documentation. Well, that aside, I suppose answering my question >> is easier when there is a proposed starting point for content. >> >> To that end, I've tried to collect a starting point based on repeated >> questions/corrections that I've seen over the years. I've added Greg to >> the Cc: in order to ensure I've captured the netdev-stable interaction >> correctly, and I've thrown Darren under the bus as a random content >> reviewer, since he has expressed an interest in documentation recently. > > And I'm going to learn how to properly interract on netdev while I'm at > it. It's a win win :-) > >> >> Below is a possible starting point for content. Many answers I have >> written are from memory, long after losing links to netdev threads that >> served as evidence for the answers, so apologies in advance if I have >> failed to recall correctly the specific details in which you would like >> to see things done. >> >> Thanks, >> Paul. >> -- >> >> Information you need to know about netdev >> ----------------------------------------- >> >> 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. >> > > > Should LKML be Cc'd? I assume so... No, not unless there is a good reason to do so. > > >> 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: >> >> http://git.kernel.org/?p=linux/kernel/git/davem/net.git >> http://git.kernel.org/?p=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 2wk merge window, > > > Best not to abbreviate, we can spare the 3 bytes for " week" :-) Will fix. > > >> 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. > > > It would be handy to have a netdev-next bot that responded to "~/^ > \[PATCH/" email (off list) during the merge window with a reminder of > this point. Not everyone is active enough in kernel development be > always aware of where we are in the cycle. Greg has a bot deal with > common mistakes, so there is precedent. Perhaps, but that is outside of the scope of this document. > > >> >> 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. >> >> 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 stablilization and bugfixes. >> >> Finally, the vX.Y gets released, and the whole cycle starts over. >> >> Q: So where are we now in this cycle? >> >> A: Load the mainline (Linus) page here: >> >> http://git.kernel.org/?p=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. >> > > > How does one determine if we are in the merge window? I wonder if we > could have DEV_CYCLE file in the linux git repository which read: > > MERGE WINDOW > BUG FIX ONLY (-rc1+) > CRITICAL FIXES ONLY (-rc4+) > > That would make it trivial to know from right there in the sources where > we are. Again, outside the scope of this document. > > >> 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" 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. 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: 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: >> http://git.kernel.org/cgit/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$ >> > > > This needs a reference to stable_kernel_rules.txt IMO, and possibly less > content here. The question is about finding whether a patch is queued, which comes up quite often, so I think the detail is warranted. The rules file is more about requirements for getting a patch _in_ stable, so the reference addition below makes sense. > > >> Q: I see a network patch and I think it should be backported to stable. >> Should I request it via "stable@vger.kernel.org" like the references in >> the kernel's Documentation/ directory say? > > stable_kernel_rules.txt specifically Will add that. > >> >> A: No, not for networking. Check the stable queues as per above 1st 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. > > > I had no idea as an infrequent contributor to netdev! > stable_kernel_rules.txt needs some exceptions noted and a reference to > this. Send Greg a patch. :) > > >> >> Before you jump to go do the above, do note that the normal stable rules >> in Documentation/stable_kernel_rules.txt 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. 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 bugfix 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 Documentation/SubmittingPatches to >> temporarily embed that information into the patch that you send. >> >> Q: Someone said that the comment style and coding convention is different >> for the networing content. Is this true? > > > networking fixed. > >> >> 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 >> */ > > > This is.... unfortunate. I see the warnings from checkpatch.pl and I > have to choose between adhering to that or keeping a file which is in > complete violation to that consistent. I risk flaming either way. > > Do we really need different coding styles for different sub directories > of the same source tree? I won't say anything more on this or try to > argue the point, it isn't my call. Just seems.... strange to me. It is what it is; I'm just documenting it here. > > >> >> Q: I 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? >> >> A: Make it the latter style, so that eventually all code in the domain of >> netdev is of this format. > > > :-) OK > > >> >> Q: I found a bug that might have possible security implications or similar. >> 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 using "security@kernel.org" instead. >> >> Q: What level of testing is expected before I submit my change? >> >> A: If your changes are against net-next, then the expectation is that > > s/then// Fixed. > >> 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. You can start with checkpatch.pl, but do not >> be mindlessly robotic in doing so. Re-read your own work as if you were >> the reviewer. 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. > > > This needs a reference to SubmittingPatches Sure, that can't hurt either. Will add it. Paul. -- > > This is great Paul, thank you for taking the time. >