Re: linux rdma 3.14 merge plans

Nicholas A. Bellinger
2014-02-07T00:02:03Z

Hi Roland,

On Tue, 2014-01-21 at 23:27 -0800, Nicholas A. Bellinger wrote:
> Roland & Co,
>
> On Tue, 2014-01-21 at 16:43 -0800, Roland Dreier wrote:
> > On Tue, Jan 21, 2014 at 2:00 PM, Or Gerlitz <or.gerlitz@gmail.com> wrote:
> > > Roland, ping! the signature patches were posted > three months ago. We
> > > deserve a response from the maintainer that goes beyond "I need to
> > > think on that".
> > >
> > > Responsiveness was stated by Linus to be the #1 requirement from
> > > kernel maintainers.
> >
> > Or, I'm not sure what response you're after from me. Linus has also
> > said that maintainers should say "no" a lot more
> > (http://lwn.net/Articles/571995/) so maybe you want me to say, "No, I
> > won't merge this patch set, since it adds a bunch of complexity to
> > support a feature no one really cares about." Is that it?
>
> The patch set proposed by Sagi + Or is modest in terms of LOC to core IB
> code, and includes mostly mlx5 specific driver changes that enables HW
> offloads.
>
> > (And yes I
> > am skeptical about this stuff — I work at an enterprise storage
> > company and even here it's hard to find anyone who cares about
> > DIF/DIX, especially offload features that stop it from being
> > end-to-end)
> >
>
> My understanding is most HBAs capable of T10 PI offload in DIX PASS +
> VERIFY mode are already implementing DIX INSERT + STRIP modes in various
> capacities to support legacy environments.
>
> Beyond the DIX INSERT + STRIP case for enterprise storage, the amount of
> FC + SAS HBAs that already support T10 PI metadata is substantial.
>
> > I'm sure you're not expecting me to say, "Sure, I'll merge it without
> > understanding the problem it's solving or how it's doing that,"
> > especially given the your recent history of pushing me to merge stuff
> > like the IP-RoCE patches back when they broke the userspace ABI.
>
> With the merge window now upon us, there is a understandable reluctance
> to merge new features. Given the amount of time the series has spent on
> the list, it is however a good candidate to consider for an exception.
>
> Short of that, are you planning to accept the series for the next round
> once the current merge window closes..?
>
> We'd really like to start enabling fabrics with these types of offloads
> for v3.15.
>

Now with the initial DIF backend taraget support in place for v3.14-rc1
code, we'd like to move forward on iser-target related pieces for T10
PI.

Can you give us an estimate of when you'll have some time to give
feedback on the outstanding patches..?

--nab