Re: [PATCH 04/16] PCI/P2PDMA: Refactor pci_p2pdma_map_type() to take pagmap and device

[John Hubbard]

On 5/3/21 3:57 PM, Jason Gunthorpe wrote:
> On Mon, May 03, 2021 at 02:54:26PM -0700, John Hubbard wrote:
>
> > I guess my main concern here is that there are these pci*() functions
> > that somehow want to pass around struct device.
>
> Well, this is the main issue - helpers being used inside IOMMU code
> should not be called pci* functions. This is some generic device p2p
> interface that happens to only support PCI to PCI transfers today.

Yes, maybe renaming a few levels of functions would help at least clarify
what the code can do. Once the code reaches layers that truly are
PCI-specific, that's where it should transition to using pci_dev args,
and that's also where it should return -ENOTSUPP back up the calling
stack.

thanks,
--
John Hubbard
NVIDIA