Re: [PATCH V5 3/3] PCI: Mask and unmask hotplug interrupts during reset

[poza]

On 2018-07-03 20:04, Lukas Wunner wrote:
> On Mon, Jul 02, 2018 at 06:52:47PM -0400, Sinan Kaya wrote:
> > @@ -308,8 +310,17 @@ void pcie_do_fatal_recovery(struct pci_dev *dev, 
> > u32 service)
> >  		pci_dev_put(pdev);
> >  	}
> >
> > +	hpsvc = pcie_port_find_service(udev, PCIE_PORT_SERVICE_HP);
> > +	hpdev = pcie_port_find_device(udev, PCIE_PORT_SERVICE_HP);
> > +
> > +	if (hpdev && hpsvc)
> > +		hpsvc->mask_irq(to_pcie_device(hpdev));
> > +
> >  	result = reset_link(udev, service);
> >
> > +	if (hpdev && hpsvc)
> > +		hpsvc->unmask_irq(to_pcie_device(hpdev));
> > +
>
> We've already got the ->reset_slot callback in struct hotplug_slot_ops,
> I'm wondering if we really need additional ones for this use case.
>
> If you just do...
>
> 	if (!pci_probe_reset_slot(dev->slot))
> 		pci_reset_slot(dev->slot)
> 	else {
> 		/* regular code path */
> 	}
>
> would that not be equivalent?

pcie_do_fatal_recovery() calls
          reset_link()
             which calls dpc_reset_link() or aer_root_reset() depending 
on the event.

and dpc_reset_link() and aer_root_reset() do their own cleanup stuffs.
infact, aer_root_reset() is the only function which actually triggers 
pci_reset_bridge_secondary_bus().

So if we try to fit in your suggestion:

if (!pci_probe_reset_slot(dev->slot))
{
    pci_reset_slot(dev->slot)
    result = reset_link(udev, service); >> in this case aer_root_reset 
must not call pci_reset_bridge_secondary_bus()
} else
    result = reset_link(udev, service); >> in this case aer_root_reset 
must call pci_reset_bridge_secondary_bus() [since bridge is not hotplug 
capable)

Did I get your suggestion right ?

Regards,
Oza.

> (It's worth noting though that pciehp is the only hotplug driver
> implementing the ->reset_slot callback.  If hotplug is handled by
> a different driver or by the platform firmware, devices may still
> be removed and re-enumerated twice.)

> Thanks,
>
> Lukas