Re: [PATCH v7 20/21] PCI/P2PDMA: Introduce pci_mmap_p2pmem()

Christoph Hellwig
2022-07-06T06:51:36Z

On Tue, Jul 05, 2022 at 12:16:45PM -0600, Logan Gunthorpe wrote:
> The current version does it through a char device, but that requires
> creating a simple_fs and anon_inode for teardown on driver removal, plus
> a bunch of hooks through the driver that exposes it (NVMe, in this case)
> to set this all up.
>
> Christoph is suggesting a sysfs interface which could potentially avoid
> the anon_inode and all of the extra hooks. It has some significant
> benefits and maybe some small downsides, but I wouldn't describe it as
> horrid.

Yeah, I don't think is is horrible, it fits in with the resource files
for the BARs, and solves a lot of problems. Greg, can you explain
what would be so bad about it?