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Commit 9d987eba authored by Andy Shevchenko's avatar Andy Shevchenko Committed by Bjorn Helgaas
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powerpc/pci: Unroll two pass loop when scanning bridges 



The current scanning code is really hard to understand because it calls the
same function in a loop where pass value is changed without any comments
explaining it:

  for (pass = 0; pass < 2; pass++)
    for_each_pci_bridge(dev, bus)
      max = pci_scan_bridge(bus, dev, max, pass);

Unfamiliar reader cannot tell easily what is the purpose of this loop
without looking at internals of pci_scan_bridge().

In order to make this bit easier to understand, open-code the loop in
pci_scan_child_bus() and pci_hp_add_bridge() with added comments.

No functional changes intended.

Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
parent dd1ea576

arch/powerpc/kernel/pci-hotplug.c

+12 −5
Original line number Diff line number Diff line
@@ -104,7 +104,7 @@ EXPORT_SYMBOL_GPL(pci_hp_remove_devices); 
 */

void pci_hp_add_devices(struct pci_bus *bus)

{

	int slotno, mode, pass, max;

	int slotno, mode, max;

	struct pci_dev *dev;

	struct pci_controller *phb;

	struct device_node *dn = pci_bus_to_OF_node(bus);
@@ -133,10 +133,17 @@ void pci_hp_add_devices(struct pci_bus *bus) 
		pci_scan_slot(bus, PCI_DEVFN(slotno, 0));

		pcibios_setup_bus_devices(bus);

		max = bus->busn_res.start;

		for (pass = 0; pass < 2; pass++) {

		/*

		 * Scan bridges that are already configured. We don't touch

		 * them unless they are misconfigured (which will be done in

		 * the second scan below).

		 */

		for_each_pci_bridge(dev, bus)

				max = pci_scan_bridge(bus, dev, max, pass);

		}

			max = pci_scan_bridge(bus, dev, max, 0);



		/* Scan bridges that need to be reconfigured */

		for_each_pci_bridge(dev, bus)

			max = pci_scan_bridge(bus, dev, max, 1);

	}

	pcibios_finish_adding_to_bus(bus);

}