Re: [PATCH v5 2/9] PCI/P2PDMA: Add CONFIG_PCI_P2PDMA_CORE

[Jason Gunthorpe <jgg@nvidia.com>]

On Tue, Aug 04, 2026 at 10:19:11AM -0600, Logan Gunthorpe wrote:

> There's a vague convention for this already: the term 'p2pmem' is often
> used for cases where the driver uses the allocator, etc. (I think I had
> this intention when I wrote the code and have since forgotten about
> it).

I've been calling it the genalloc layer and the core layer. p2pmem
would be OK to refer to the genalloc stuff. So if you want to have
CONFIG_PCI_P2PDMA and CONFIG_PCI_P2PMEM that seem sOk

> code into it's own file, potentially renaming some functions. Then, in
> the end, we would probably have a pcim_p2pdma_supported() function and a
> pcim_p2pmem_supported() function, the latter being used by existing use
> cases.

Not quite sure why we need this?

Matt, the mlx5 stuff is the same as VFIO, it just uses the "core"
layer and does not use the genalloc. So there shouldn't be an issue
here, if the genalloc is off then the mlx5 stuff should still
work. There shouldn't be a case where CONFIG_PCI_P2PDMA=y and mlx5 is
broken?

Did some of APIs get mixed into the genalloc family that should not
have?

Jason