RE: [PATCH v5 1/4] IB/netlink: Add defines for local service requests through netlink

Weiny, Ira
2015-06-12T05:24:32Z

>
> > From: Jason Gunthorpe [mailto:jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org]
> > Sent: Thursday, June 11, 2015 8:22 PM
> > To: Wan, Kaike
> > Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; Fleck, John; Weiny, Ira
> > Subject: Re: [PATCH v5 1/4] IB/netlink: Add defines for local service
> > requests through netlink
> >
> > On Thu, Jun 11, 2015 at 11:45:46PM +0000, Wan, Kaike wrote:
> > > Apparently, to achieve this goal, we need the following changes:
> >
> > I don't expect anything more than a proper hole in the UAPI to make
> > this work.
> >
> > I already have patches that implement full kernel support for the
> > 6-path format, and globally enable APM. With this netlink interface it
> > becomes feasible to mainline them. That will require some reworking of
> > what you've done, but I don't expect you to do that.
> >
> > The only remaining thing we need here is that tiny bit of policy
> > information for the kernel to specify what the intended use of the path is:
> > - For connected CM operation (6 path records)
> > - For unidirectional UD (1 path record)
> > - For 'misc' GMP like operation (at least 1 reversible path record)
> >
> > I'm happy if you call it PATH_USE_XX
> >
> > Testing the reversible bit should be enough to rough this in, if not
> > reversible it is PATH_USE_UNIDIRECTIONAL_UD, otherwise it is
> PATH_USE_GMP.
> >

PATH_USE_* is a better name. But I think the defines should be:

PATH_USE_ANY (or ALL?)
PATH_USE_UNIDIRECTIONAL
PATH_USE_GMP

> > Recommend that userspace treat any unknown usage type as GMP (it is
> > the
>
> > most general).

Why not treat unknown type as "ANY/ALL" and return all 6 if possible. If not possible/supported (ie like ibacm) return GMP which is always valid.

>
> That would be cool. If we add this attribute, should we remove reversible and
> numb_path attributes?

Yes.

>
> Kaike
>
> >
> > Ira: Do you like 'path use' better as a name? I think I do..

Yea that is a much better name.

Thanks,
Ira