Re: [PATCH 1/3] xen/arm: Sync sysregs and cpuinfo with Linux 5.18-rc3

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 11 May 2022, Bertrand Marquis wrote:
> > I understand the patch is already written, so I was OK if you simply list 
> > of the commits with the authors/tags for this time.
> 
> I would like to understand where this requirement is coming from.
> 
> @George: is there some kind of legal reason for something like that ?

I am not George but I'll answer the legal question. Our "legal" document
is the DCO:

https://developercertificate.org/

This falls under case (b):

(b) The contribution is based upon previous work that, to the best
    of my knowledge, is covered under an appropriate open source
    license and I have the right under that license to submit that
    work with modifications, whether created in whole or in part
    by me, under the same open source license (unless I am
    permitted to submit under a different license), as indicated
    in the file; or

So from the legal point of view only your Signed-off-by line is
required.

I remember this well because I was confused about this a few years ago
in another case of taking code from Linux.


> > If both Stefano and you agree to not keep the authorships, then I will
> > not stand against it. However, I will not get involved in
> > committing and adding my ack.

I am fine either way. My only request is to mention the Linux commit-id
that Bertrand used as a base and Bertrand has already done that.


> I want first to clear up this process and understand why you are
> requesting this to know how I should do anything like that in the
> future.

It looks like our process docs are not very good on this point and might
benefit from a clarification. I hope you are volunteering :-)

Origin is defined as "it specifies the source of the patch" but it
doesn't say what actually is considered a "source".

I suggest to distinguish between the case where commits are ported
individually from the case where code is copied over (like when we
introduced SMMUv3.) If commits are copied individually, I think we
probably want an Origin tag for each of them and the source is the
original commit-id. If the code is copied from Linux (like the SMMUv3
case) then we probably only want to request a single Origin tag (or a
new tag?) with the base Linux version (5.18-rc3) rather than the
commit-id being backported. In that case the source would be the
repository baseline.

Cheers,

Stefano