On Mon, Jun 21, 2021 at 02:28:48PM +0200, Daniel Vetter wrote:

Mission acomplished, we've gone full circle, and the totally-not-a-gpu
driver is now trying to use gpu infrastructure. And seems to have
gained vram meanwhile too. Next up is going to be synchronization
using dma_fence so you can pass buffers back&forth without stalls
among drivers.

Well, we can't even see the other side of this so who knows

This is a new uAPI, where is the userspace? In RDMA at least I require
to see the new userspace and test suite before changes to
include/uapi/rdma can go ahead.

Doug/Jason from infiniband: Should we add linux-rdma to the dma-buf
wildcard match so that you can catch these next time around too? At
least when people use scripts/get_maintainers.pl correctly. All the
other subsystems using dma-buf are on there already (dri-devel,
linux-media and linaro-mm-sig for android/arm embedded stuff).

My bigger concern is this doesn't seem to be implementing PCI P2P DMA
correctly. This is following the same hacky NULL page approach that
Christoph Hellwig already NAK'd for AMD.

This should not be allowed to proliferate.

I would be much happier seeing this be done using the approach of
Logan's series here:

https://lore.kernel.org/linux-block/20210513223203.5542-1-logang@deltatee.com/ (local)

Jason