Re: [PATCH 06/12] IB/core: Add optional PCI P2P flag to rdma_rw_ctx_[init|destroy]()

On Mon, Jan 08, 2018 at 11:17:38AM -0700, Logan Gunthorpe wrote:
 

quoted

quoted

If at all it should be in the dma_map* wrappers, but for that we'd need
a good identifier.  And it still would not solve the whole fake dma
ops issue.

Very long term the IOMMUs under the ops will need to care about this,
so the wrapper is not an optimal place to put it - but I wouldn't
object if it gets it out of RDMA :)

Well, creating the extra op doesn't really change anything to the RDMA patch
in this series.

Not fundamentally, but it lets us solve the bugs the patch introduces
with hfi/etc

The point is, for the time being, we need to track whether we are
doing a P2P or normal mapping using a side channel as we don't have
a good way of tracking it in the SGL at this time.

Well, that is disappointing for now, but I'm OK with the flag in the
RW interface - as long as we all sort of agree it is not desirable and
the SG should self-identify in an ideal someday future world..

Jason