Re: [PATCH v4 02/11] PCI: liveupdate: Track outgoing preserved PCI devices

[Samiullah Khawaja]

On Thu, Apr 30, 2026 at 09:15:14PM +0000, David Matlack wrote:
> On 2026-04-28 05:24 PM, Samiullah Khawaja wrote:
> > On Thu, Apr 23, 2026 at 09:23:06PM +0000, David Matlack wrote:
>
> > > +	for (i = 0; i < ser->max_nr_devices; i++) {
> > > +		/*
> > > +		 * Start searching at index ser->nr_devices. This should result
> > > +		 * in a constant time search under expected conditions (devices
> > > +		 * are not getting unpreserved).
> > > +		 */
> > > +		int index = (ser->nr_devices + i) % ser->max_nr_devices;
> > > +		struct pci_dev_ser *dev_ser = &ser->devices[index];
> >
> > nit: Maybe we can move this logic in a separate function as down the road
> > when we expand this to add VFs and Hotpluggable devices, this might
> > change significantly? It's good if it is self-contained.
>
> Did you mean to leave this comment on pci_flb_preserve() where it
> decides how many devices to allocate room for?

I was talking about this one, as I think depending on the scheme we take
this might change significantly. Just a nit, you can ignore it.
> > > +static inline struct pci_dev_ser *pci_liveupdate_outgoing(struct pci_dev *dev)
> > > +{
> > > +	return dev->liveupdate_outgoing;
> > > +}
> >
> > Is this expected to be called under the outgoing lock?
>
> For now this API is only used during shutdown, at which point userspace
> should have already been stopped so drivers should not be changing the
> preservation status of an outgoing device. So I don't think this needs
> to be under the outgoing lock, but it would be nice to have some more
> explicit synchronization.

Ok that makes sense. I have similar cases in my series, but maybe we can
add kdoc regarding these stating in which context this is expected to be
used?