Re: [PATCH v18 05/11] PCI/ERR: Remove service dependency in pcie_do_recovery()

[Kuppuswamy, Sathyanarayanan]

Hi Bjorn,

On 3/28/20 2:32 PM, Bjorn Helgaas wrote:
> On Sat, Mar 28, 2020 at 02:12:48PM -0700, Kuppuswamy, Sathyanarayanan wrote:
> > On 3/23/20 5:26 PM, sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx wrote:
> > > From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> >
> > > +void pcie_do_recovery(struct pci_dev *dev,
> > > +		      enum pci_channel_state state,
> > > +		      pci_ers_result_t (*reset_link)(struct pci_dev *pdev))
> > >    {
> > >    	pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
> > >    	struct pci_bus *bus;
> > > @@ -206,9 +165,12 @@ void pcie_do_recovery(struct pci_dev *dev, enum pci_channel_state state,
> > >    	pci_dbg(dev, "broadcast error_detected message\n");
> > >    	if (state == pci_channel_io_frozen) {
> > >    		pci_walk_bus(bus, report_frozen_detected, &status);
> > > -		status = reset_link(dev, service);
> > > -		if 		if (reset_link)
> > 			status = reset_link(dev);(status == PCI_ERS_RESULT_DISCONNECT
> > > +		status = reset_link(dev);
> > Above line needs to be replaced as below. Since there is a
> > possibility reset_link can NULL (eventhough currently its
> > not true).
> > 		if (reset_link)
> > 			status = reset_link(dev);
> > Shall I submit another version to add above fix on top of
> > our pci/edr branch ?
>
> No, I can squash that in if needed.
>
> But I don't actually think we *do* need it.  All the callers supply a
> valid reset_link function pointer, and if somebody changes or adds a
> new one that doesn't, I'd rather take the null pointer exception and
> find out about it than silently ignore it.
But the documentation says "If reset_link is not NULL, recovery function
will use it to reset the link." It considers NULL as a possible case.
So I think its better to allow that case with a pci_warn() message.
> Bjorn