Re: [PATCH v16 5/9] PCI/AER: Factor out error reporting from AER

[poza]

On 2018-05-11 21:24, Lukas Wunner wrote:
> On Fri, May 11, 2018 at 09:04:36PM +0530, poza@xxxxxxxxxxxxxx wrote:
> > On 2018-05-11 18:28, Lukas Wunner wrote:
> > >On Fri, May 11, 2018 at 06:43:24AM -0400, Oza Pawandeep wrote:
> > >>+void pcie_do_fatal_recovery(struct pci_dev *dev)
> > >>+{
> > >>+	struct pci_dev *udev;
> > >>+	struct pci_bus *parent;
> > >>+	struct pci_dev *pdev, *temp;
> > >>+	pci_ers_result_t result = PCI_ERS_RESULT_RECOVERED;
> > >>+	struct aer_broadcast_data result_data;
> > >>+
> > >>+	if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)
> > >>+		udev = dev;
> > >>+	else
> > >>+		udev = dev->bus->self;
> > >>+
> > >>+	parent = udev->subordinate;
> > >>+	pci_lock_rescan_remove();
> > >>+	list_for_each_entry_safe_reverse(pdev, temp, &parent->devices,
> > >>+				 bus_list) {
> > >>+		pci_dev_get(pdev);
> > >>+		pci_dev_set_disconnected(pdev, NULL);
> > >>+		if (pci_has_subordinate(pdev))
> > >>+			pci_walk_bus(pdev->subordinate,
> > >>+				     pci_dev_set_disconnected, NULL);
> > >>+		pci_stop_and_remove_bus_device(pdev);
> > >>+		pci_dev_put(pdev);
> > >>+	}
> > >
> > >Any reason not to simply call
> > >
> > >	pci_walk_bus(udev->subordinate, pci_dev_set_disconnected, NULL);
> > >
> > >before the list_for_each_entry_safe_reverse() iteration, instead of
> > >calling it for each device on the subordinate bus and for each
> > >device's children?  Should be semantically identical, saves 3 LoC
> > >and saves wasted cycles of acquiring pci_bus_sem over and over again
> > >for each device on the subordinate bus.
> >
> > Well this is borrowed code from DPC driver, hence I thought to keep 
> > the
> > same.
> > but to me it looks like its taking care of PCIe switch where is goes 
> > through
> > all the subordinates, and which could turn out to be more swicthes 
> > down the
> > line, and son on...
> > it goes all the way down to the tree
>
> ... which is precisely what the one line I suggested above does.
>
> You don't need to respin for this alone as far as I'm concerned,
> but please post a follow-up refactoring patch.  I have a patch
> in the pipeline which makes the same change in pciehp, hence this
> caught my eye.
>
> Thanks,
>
> Lukas

Thanks Lukas, I will keep this in my pipeline as an optimization.
appreciate your input.

Regards,
Oza.