[PATCH v6 06/13] nvme-pci: implement dma-buf backed requests

[Pavel Begunkov]

Hi Christoph,

On 9/22/26 14:20, Christoph Hellwig wrote:
> On Mon, Sep 21, 2026 at 02:38:50PM +0100, Pavel Begunkov wrote:
>> Enable BIO_DMABUF_MAP backed requests. On registration we map the
> 
> This is now REQ_DMABUF.

Will change

> Sashiko had a few comments, which I think are correct - if we use
> dma_map_sg to map the data, we need to use the sync_sg APIs to
> transfer ownership.  That only matters on non-coherent architectures
> with MMU, but we need to get it right.

I've seen that and fixed everything locally that should be fixed,
apart from the sync. I wonder what we can do about that? I can
somehow replace it with the sg variant for now, but sync'ing the
entire possibly multi-GB mapping for, let's say, a 512B I/O, sounds
not wise. And I can think of another place that does mix sync_single
with sgs.

> And the reset deadlock also looks plausible.
-- 
Pavel Begunkov