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

Lukas Wunner
2018-05-11T15:54:22Z

On Fri, May 11, 2018 at 09:04:36PM +0530, poza@codeaurora.org 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