kdbus and Fedora

[Josh Boyer]

Hi All,

Harald and I were recently talking about kdbus and how it plays into
Fedora.  Right now, the kernel-playground COPR is carrying the kdbus
patches, but that isn't widely used and isn't included in a broad test
base. Obviously our distribution is heavily entwined with D-Bus and we
were looking to see if it was possible to help kdbus testing and
development by doing some kind of integration within Fedora itself.  I
promised Harald I would talk it over with the other Fedora kernel
maintainers and after a brief discussion we came up with the following
possible proposal.

If Fedora were to carry kdbus in any form, the following things would
be required:

1) There would be a single canonical location to track kdbus
development.  After talking with Harald, that should be the upstream
tree that gregkh is using to submit patches.

2) Harald's team (systemd, etc) would commit to testing the system
both with and without kdbus active.  Obviously we do not want to
enforce reliance on something as core critical as kdbus while it is
still being actively developed upstream.  That could cause a lot of
deviation down the road and it isn't the aim here.

3) kdbus would only be carried in the rawhide branch until it is
merged upstream.  As a concrete example, if kdbus was not merged in
the upstream kernel at the time rel-eng creates the F23 branches, then
Fedora 23 will never get kdbus.  It will be carried in rawhide and
rawhide only until it's accepted upstream.  The maintainers actually
hope this does get merged but we want to make sure we are prepared to
drop this without causing too much trouble if needed.

4) After discussing a bit with the rest of the Fedora kernel
maintainers, we would carry an additional patch that would require
'kdbus-enabled' to be specified before the kernel would allow kdbus to
be loaded (or similar mechanism).  This would focus the main testing
effort for all the default images to remain as they are today, while
easily allowing the plumbing layer developers access to kdbus for
their enablement testing.

These conditions would hopefully help the Fedora kernel maintainers
avoid some of the pitfalls of carrying a large chunk of out of tree
code and if they're all met we feel fairly comfortable with doing
this.  We wanted to send this out for a bit wider discussion and
review before proceeding with it, and I agreed to start this thread so
here we are.

Harald, does the above look like what you were envisioning when we
talked earlier?

josh