Re: [RFC PATCH] RDMA/cma: Remove netlink interface of CMA statistics

Or Gerlitz
2017-11-14T08:51:31Z

On Tue, Nov 14, 2017 at 10:05 AM, Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
>
> On Mon, Nov 13, 2017 at 12:24:32PM -0700, Jason Gunthorpe wrote:
> > On Mon, Nov 13, 2017 at 04:40:24PM +0200, Leon Romanovsky wrote:
> > > From: Leon Romanovsky <leonro-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> > >
> > > CMA statistics were exposed to users through netlink interface long time
> > > ago, but it wasn't exposed using netlink extensibility approach. The
> > > current implementation was based on struct and not attributes.
> > >
> > > Let's remove it, before anyone is actually start to use it and prevents us
> > > to write it properly.
> >
> > You should describe why you think it is safe to remove a uAPI from the
> > kernel in the commit message.. When was it introduced? Why was a uAPI
> > added with no users??
>
> I didn't want to invest time before I actually see that it is possible.
> The purpose of this RFC is to hear feedback and see if anyone cares enough
> about that code.
>
> The code was introduced a long time ago [1]

missing ref

>
> as an attempt to provide netstat-like information. It had simple demo application, which didn't
> work for me

what didn't work exactly?

This is UAPI, if you want to remove it, make sure to provide a good
replacement and see
if/what is the upstream procedure for UAPI changes/removals, I guess
there is such, sending
email to a subsystem list doesn't seem enough to me.

>
> before I started to refactor ib_netlink.
>
> Also latest fixes from Parav in the actual callback implementation support
> my feelings that the kernel part is broken too.
>
> Is it enough to proceed with the submission of actual patch?