On Thu, Jan 08, 2026 at 10:19:18AM +0800, Ming Lei wrote:

quoted

The feature is in no way nvme specific.  nvme is just the initial
underlying driver.  It makes total sense to support this for any high
performance block device, and to pass it through file systems.

But why does FS care the dma buffer attachment? Since high performance
host controller is exactly the dma buffer attachment point.

I can't parse what you're trying to say here.

If the callback is added in `struct file_operations` for wiring dma buffer
and the importer(host contrller), you will see it is hard to let it cross device
mapper/raid or other stackable block devices.

Why?

But even when not stacking, the registration still needs to go
through the file system even for a single device, never mind multiple
controlled by the file system.