Issue with AWUPF when using multiple controllers in a subsystem

[Christoph Hellwig]

On Thu, Apr 10, 2025 at 01:33:38AM +0000, Chaitanya Kulkarni wrote:
> if we stop supporting AWUPF and move to NAWUPF then will it break where
> exiting controller's that doesn't support NAWUPF but only supports
> controller wide AWUPF, IOW NSFEAT bit 1 == 0 meaning per-namespace
> atomic info is not valid ? [1]

Yes.

> Looking at the spec NAWUPF values can differ for namespaces attached
> to the same controller and those values can also differ from
> AWUPF ? [2]

That's the whole point of NAWUPF.

> Perhaps using the minimum of all AWUPF and rejecting any ctrl which are
> lower than the initial value is right fix ?

That's what I mean in my previous mail.