[PATCH v7 0/3] FDP and per-io hints

[Christoph Hellwig]

On Wed, Oct 02, 2024 at 09:33:16AM -0600, Keith Busch wrote:
> You remember right. I also explained the use cases for per-io hints are
> to replace current passthrough users with generic read/write paths that
> have all the memory guard rails, read/write stats, and other features
> that you don't get with passthrough. This just lets you accomplish the
> same placement hints with the nvme raw block device that you get with
> the nvme char device.

Yes, and as I said before we need an opt-in from the file_ops, because
file systems can't support this.  And I'm speaking that from a position
of working on a file system that made the existing non-idea hints
work (to all fairness Hans did the hard work, but I was part of it).