Re: [PATCH v4 0/4] Implement dmabuf direct I/O via copy_file_range

[Christian König]

On 6/3/25 15:00, Christoph Hellwig wrote:
> This is a really weird interface.  No one has yet to explain why dmabuf
> is so special that we can't support direct I/O to it when we can support
> it to otherwise exotic mappings like PCI P2P ones.

With udmabuf you can do direct I/O, it's just inefficient to walk the page tables for it when you already have an array of all the folios.

Regards,
Christian.