[RFC] Any value in having a netdev FAQ?

[RFC] Any value in having a netdev FAQ?

[Paul Gortmaker]

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.

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.

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,
   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.

   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.

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$ 

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?

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.

   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?

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.  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.
   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
   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.

Re: [RFC] Any value in having a netdev FAQ?

[David Miller]

From: Paul Gortmaker <paul.gortmaker@windriver.com>
Date: Mon, 15 Jul 2013 22:59:54 -0400

> 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.
> 
> 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 a lot for writing this, it is useful.

I think it's easier if this lives somewhere under
Documentation/networking in the kernel tree, then we can just point
people at it.

What do you think?

Re: [RFC] Any value in having a netdev FAQ?

[Darren Hart]

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...


> 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" :-)


>    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.


> 
>    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.


> 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.


> 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

> 
> 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.


> 
>    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

> 
> 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.


> 
> 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//

>    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

This is great Paul, thank you for taking the time.

-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel

Re: [RFC] Any value in having a netdev FAQ?

[Darren Hart]

On Tue, 2013-07-16 at 13:05 -0700, David Miller wrote:
> From: Paul Gortmaker <paul.gortmaker@windriver.com>
> Date: Mon, 15 Jul 2013 22:59:54 -0400
> 
> > 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.
> > 
> > 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 a lot for writing this, it is useful.
> 
> I think it's easier if this lives somewhere under
> Documentation/networking in the kernel tree, then we can just point
> people at it.
> 
> What do you think?

I was going to recommend the same. Ideally we would have sort of
consistent documentation subsystem policy naming scheme to aid in
finding and referencing documents.

Documentation/contributing.txt
Documentation/networking/contibuting.txt
Documentation/stable/contributing.txt

That might not be the best choice in naming, but consistency always
makes things easier to find, especially in such a large system.

-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel

Re: [RFC] Any value in having a netdev FAQ?

[Darren Hart]

On Tue, 2013-07-16 at 13:05 -0700, David Miller wrote:
> From: Paul Gortmaker <paul.gortmaker@windriver.com>
> Date: Mon, 15 Jul 2013 22:59:54 -0400
> 
> > 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.
> > 
> > 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 a lot for writing this, it is useful.
> 
> I think it's easier if this lives somewhere under
> Documentation/networking in the kernel tree, then we can just point
> people at it.
> 
> What do you think?

Maybe netdev_kernel_rules.txt, in keeping with the well-known
stable_kernel_rules.txt?

-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel

Re: [RFC] Any value in having a netdev FAQ?

[Joe Perches]

On Mon, 2013-07-15 at 22:59 -0400, Paul Gortmaker wrote:
> 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.

Suggest checkpatch.pl --strict because there are some
style elements (like multi-line statement alignment)
where checkpatch bleats with --strict that are commonly
used in net and drivers/net. 

email the proposed patch to yourself and make sure it
applies cleanly before sending it to the netdev mailing
list.

Re: [RFC] Any value in having a netdev FAQ?

[Paul Gortmaker]

On 13-07-16 04:05 PM, David Miller wrote:
> From: Paul Gortmaker <paul.gortmaker@windriver.com>
> Date: Mon, 15 Jul 2013 22:59:54 -0400
> 
>> 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.
>>
>> 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 a lot for writing this, it is useful.
> 
> I think it's easier if this lives somewhere under
> Documentation/networking in the kernel tree, then we can just point
> people at it.
> 
> What do you think?

Sounds fine to me, I'll make some of the corrections Darren pointed out
and send it along as a patch.

Re: [RFC] Any value in having a netdev FAQ?

[Paul Gortmaker]

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.
> 

Re: [RFC] Any value in having a netdev FAQ?

[Joe Perches]

On Wed, 2013-07-17 at 11:18 -0400, Paul Gortmaker wrote:

> > 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.

Not that duplication is bad, but that comment style
variation is documented in CodingStyle.

Re: [RFC] Any value in having a netdev FAQ?

[Darren Hart]

On Mon, 2013-07-15 at 22:59 -0400, Paul Gortmaker wrote:

>    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.

So I misunderstood this line apparently. I checked Linus tree:

$ git show v3.11-rc1
tag v3.11-rc1
Tagger: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sun Jul 14 15:18:41 2013 -0700

Linux 3.11-rc1

And seeing that rc1 had been tagged 3 days ago, submitted the pch_gbe
patch for MinnowBoard to netdev for net-next. David *very* politely :-)
asked me to resubmit when the net-next tree was open. It appears to me
then that we need to add a bit here about searching the archives
mentioned above for the last netdev-is-open message (I presume there is
a common subject format) to know whether a patch will be welcomed or
not.

I am not subscribed to netdev as I contribute only very rarely. Is it
considered a requirement that one be subscribed to netdev in order to
contribute? If so, we should add that here as well.


-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel

Re: [RFC] Any value in having a netdev FAQ?

[Hannes Frederic Sowa]

Thanks for the great FAQ!

On Mon, Jul 15, 2013 at 10:59:54PM -0400, Paul Gortmaker wrote:
> 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.

I don't have a strong opinion on that, just a proposal (and I certainly don't
want to start another discussion about that):

Maybe we could give a hint about the linux-distros mailing list here, too?
<http://oss-security.openwall.org/wiki/mailing-lists/distros>

Thanks,

  Hannes

Re: [RFC] Any value in having a netdev FAQ?

[Paul Gortmaker]

On 13-07-17 09:55 PM, Darren Hart wrote:
> On Mon, 2013-07-15 at 22:59 -0400, Paul Gortmaker wrote:
> 
>>    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.
> 
> So I misunderstood this line apparently. I checked Linus tree:
> 
> $ git show v3.11-rc1
> tag v3.11-rc1
> Tagger: Linus Torvalds <torvalds@linux-foundation.org>
> Date:   Sun Jul 14 15:18:41 2013 -0700
> 
> Linux 3.11-rc1
> 
> And seeing that rc1 had been tagged 3 days ago, submitted the pch_gbe
> patch for MinnowBoard to netdev for net-next. David *very* politely :-)
> asked me to resubmit when the net-next tree was open. It appears to me
> then that we need to add a bit here about searching the archives
> mentioned above for the last netdev-is-open message (I presume there is
> a common subject format) to know whether a patch will be welcomed or
> not.

I will append under the "Shortly after..." text something like:

  "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."

That "link above" would be this:

http://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git

P.
--

> 
> I am not subscribed to netdev as I contribute only very rarely. Is it
> considered a requirement that one be subscribed to netdev in order to
> contribute? If so, we should add that here as well.
> 
> 

Re: [RFC] Any value in having a netdev FAQ?

[Rick Jones]

On 07/17/2013 06:55 PM, Darren Hart wrote:
> On Mon, 2013-07-15 at 22:59 -0400, Paul Gortmaker wrote:
>
>>     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.
>

yesterday I tried to send an email to Jeremy Kerr asking if there was 
some way to tweak patchwork to allow DaveM a way to signal net-next 
being closed - perhaps some message at 
http://patchwork.ozlabs.org/project/netdev/list/  Baring that, I 
wondered if it would be possible to submit a dummy "[PATCH net-next] 
net-next closed until futher notice" patch,  and fake-out the date to be 
some point in the future, so it would appear at the top of the list of 
patches.

rick jones

Re: [RFC] Any value in having a netdev FAQ?

[Benjamin Poirier]

On 2013/07/17 11:18, Paul Gortmaker wrote:
> On 13-07-16 04:32 PM, Darren Hart wrote:
> >>
> >>    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.
> 

That advice would run counter to what's in
Documentation/SubmittingPatches:

  6) Select your CC (e-mail carbon copy) list.

  Unless you have a reason NOT to do so, CC linux-kernel@vger.kernel.org.

Also, get-maintainers includes lkml all the time.