[ovs-dev] [PATCH v2 14/17] datapath: Fix skb->protocol for vlan frames

[Joe Stringer]

On 18 January 2017 at 11:54, Eric Garver <e at erig.me> wrote:
> On Tue, Jan 17, 2017 at 12:37:19AM +0000, Yang, Yi Y wrote:
>> What userspace do "802.1ad patches" depend on? Per Pravin's statement, we just backport 802.1ad patches to ovs, then the below patch can be applied to ovs.
>
> Userspace does not yet have support for 802.1ad. I'm still working on
> it. You can check the list archives for a recent RFC version.
>
> I don't know if it's acceptable to backport the datapath (kernel module)
> support before the userspace support is accepted. If not, you'll have to
> wait on the userspace.
> Perhaps Pravin can answer.

IMO the general method of:
1) Add support upstream
2) Add userspace support
3) Add backport

...works nicely because we get feedback for all interested parties for
the APIs in (1), (2) can add tests and be easily tested against a
version that works (upstream kernel) and a version that doesn't
(version in tree) to ensure both cases are handled in a reasonable
way, then (3) allows people on older kernels to gain access to the
newer features.

That said, if other people are blocking on (3) then I think that piece
should be expedited. Let's say (2) and (3) were swapped, it just means
we need to be a bit more careful when reviewing/testing to check that
the newer userspace still handles old kernels (that lack support)
fine.

The nice thing about getting the backport earlier is, the closer to
upstream we are, the sooner we may find issues that affect the latest
code.