On 31/08/18 11:38 AM, Christian König wrote: > If you can separate out adding the detection I can take a look adding > this with my DMA-buf P2P efforts. Oh, maybe my previous email wasn't clear, but I'd say that detection is already separate from ZONE_DEVICE. Nothing really needs to be changed. I just think you'll probably want to write you're own function similar to pci_p2pdma_distance that perhaps just takes two pci_devs instead of the list of clients as is needed by nvme-of-like users. To enable a whitelist we just have to handle the case where upstream_bridge_distance() returns -1 and check if the devices are in the same root complex with supported root ports before deciding the transaction is not supported. Logan
