[PATCH V4 7/7] PCI: Handle link reset via hotplug if supported

On Thu, Jun 28, 2018 at 10:31 PM, Sinan Kaya [off-list ref] wrote:

If a bridge supports hotplug and observes a PCIe fatal error, the following
events happen:

1. AER driver removes the devices from PCI tree on fatal error
2. AER driver brings down the link by issuing a secondary bus reset waits
for the link to come up.
3. Hotplug driver observes a link down interrupt
4. Hotplug driver tries to remove the devices waiting for the rescan lock
but devices are already removed by the AER driver and AER driver is waiting
for the link to come back up.
5. AER driver tries to re-enumerate devices after polling for the link
state to go up.
6. Hotplug driver obtains the lock and tries to remove the devices again.

If a bridge is a hotplug capable bridge, bounce the error handling to the
hotplug driver so that hotplug driver can mask link up/down interrupts
while performing a secondary bus reset.

+static pci_ers_result_t pciehp_reset_link(struct pci_dev *pdev)
+{
+       struct pcie_device *pciedev;
+       struct controller *ctrl;
+       struct device *devhp;
+       struct slot *slot;
+       int rc;
+
+       devhp = pcie_port_find_device(pdev, PCIE_PORT_SERVICE_HP);
+       pciedev = to_pcie_device(devhp);
+       ctrl = get_service_data(pciedev);
+       slot = ctrl->slot;
+
+       rc = reset_slot(slot->hotplug_slot, 0);
+
+       return !rc ? PCI_ERS_RESULT_RECOVERED : PCI_ERS_RESULT_DISCONNECT;

Would it be better to

return rc ? ..._DISCONNECT : ..._RECOVERED; ?

+}

-- 
With Best Regards,
Andy Shevchenko