Re: [PATCH] RDMA/rxe: Split rxe_invalidate_mr into local and remote versions

[Jason Gunthorpe <jgg@ziepe.ca>]

On Tue, Jun 28, 2022 at 06:46:39PM +0200, haris iqbal wrote:
> On Tue, Jun 28, 2022 at 6:34 PM Jason Gunthorpe <jgg@ziepe.ca> wrote:
> >
> > On Tue, Jun 28, 2022 at 06:21:09PM +0200, haris iqbal wrote:
> >
> > > > Yes, no driver in Linux suports a disjoint key space.
> > >
> > > If disjoint key space is not supported in Linux; does this mean
> > > irrespective of whether an MR is registered (IB_WR_REG_MR) for LOCAL
> > > or REMOTE access, both rkey and lkey should be set?
> >
> > No.. It means given any key the driver can always tell if it is a rkey
> > or a lkey. There is never any aliasing of key values. Thus the API
> > often doesn't have a away to tell if the given key is an rkey or lkey.
> >
> > > PS: This discussion started in the following thread,
> > > https://marc.info/?l=linux-rdma&m=165390868832428&w=2
> >
> > rxe is incorrect to not accept the lkey presented on the
> > invalidate_rkey input. invalidate_rkey is misnamed.
> 
> 
> Understood. So a better fix for rxe (as compared to the one I sent)
> would be one of the following (if I understand correctly).
> 
> 1) The key sent in INV, is compared with lkey or rkey based on which
> one is set (non-zero).

This one seems to match the spec

However, it requires that keys don't alias, I don't know if rxe has
done this.

> OR,
> 2) The key sent in INV, is compared with lkey if the MR has only LOCAL
> access, and rkey if the MR has REMOTE access.

That might make more sense if rxe has aliasing keys and you need to be
specific about r/l

Jason