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

poza
2018-05-11T16:11:22Z

On 2018-05-11 21:24, Lukas Wunner wrote:
> 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

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

Regards,
Oza.