Re: [PATCH] nvme: remove multipath module parameter

[Keith Busch <kbusch@kernel.org>]

On Thu, Mar 06, 2025 at 03:18:37PM +0100, Christoph Hellwig wrote:
> On Thu, Mar 06, 2025 at 08:12:03AM +0100, Hannes Reinecke wrote:
> > Single ported.
> > There is a range of Samsung NVMe where one is a normal, single ported,
> > NVMe, and one with a nearly identical model number reporting CMIC.
> >
> > Causing _quite_ a lot of confusion with the customer (and L3) when
> > used under MD, as for the first hotplug works, for the second ... not so 
> > much.
> 
> If the device is indeed entirely single ported and Samsung can confirm
> the setting is incorret and not easily fixable by a firmware update
> we can quirk it.

It's not one vendor or device. Making this a quirk is a good way to get
the mailing list spammed with requests to add yet another device to a
quirk table.

Or consider a true multiport PCIe where each port connects to a
different host. Each host sees a single port so they're not using
multipath capabilities, and the admin wants the MD behavior that removes
a disk on hot plug. Or even if one host sees both paths of a multiport
PCIe, they still might want that hot plug behavior. The module parameter
makes that possible, so some equivalent should be available before
removing it.