fix atomic limits check

[Christoph Hellwig]

On Fri, Jun 13, 2025 at 02:22:00PM -0700, alan.adamson at oracle.com wrote:
> Some testing with my qemu-nvme atomic write setup.  My qemu includes ns 
> atomic parameters that isn't upstream yet.

> A single subsystem with 4 controllers, 1 of the controllers has 2 
> namespaces.

.. and none of the namespaces are shared if I parse the command line
right?

> Does this look right?

I think it does, at least if I understand the setup correctly.

> Before, we had a single atomic_write_max_bytes value per subsystem.  
> That's not the case now.

Yes, with AWUPF the value should be different for namespaces with
different LBA sizes, and with NAWUPF it could be different per namespaces.

Maybe we want an extra sanity check to catch a subsystem reporting
differnet NAWUPF for the same namespace attached to multiple controllers,
even if that's against the spec.

And I wonder how we can come up with a testcase to validate all these
checks..