On Tue, 2017-04-18 at 15:22 -0600, Jason Gunthorpe wrote: > On Tue, Apr 18, 2017 at 02:11:33PM -0700, Dan Williams wrote: > > > I think this opens an even bigger can of worms.. > > > > No, I don't think it does. You'd only shim when the target page is > > backed by a device, not host memory, and you can figure this out by > > a > > is_zone_device_page()-style lookup. > > The bigger can of worms is how do you meaningfully stack dma_ops. > > What does the p2p provider do when it detects a p2p page? Yeah I think we don't really want to stack dma_ops... thinking more about it. As I just wrote, it looks like we might need a more specialised hook in the devmap to be used by the main dma_op, on a per-page basis. Ben.
