PCI: assign ioapic resource at hotplug

We need to assign resources to ioapics being hot-added. This patch
changes pbus_assign_resources_sorted() to assign resources if the
ioapic has no assigned resources.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: MUNEDA Takahiro <muneda.takahiro@jp.fujitsu.com>
Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/pci/setup-bus.c

@@ -55,12 +55,19 @@ pbus_assign_resources_sorted(struct pci_bus *bus)
 	list_for_each_entry(dev, &bus->devices, bus_list) {
 		u16 class = dev->class >> 8;
 
-		/* Don't touch classless devices or host bridges or ioapics.  */
+		/* Don't touch classless devices or host bridges. */
 		if (class == PCI_CLASS_NOT_DEFINED ||
-		    class == PCI_CLASS_BRIDGE_HOST ||
-		    class == PCI_CLASS_SYSTEM_PIC)
+		    class == PCI_CLASS_BRIDGE_HOST)
 			continue;
 
+		/* Don't touch ioapics if it has the assigned resources. */
+		if (class == PCI_CLASS_SYSTEM_PIC) {
+			res = &dev->resource[0];
+			if (res[0].start || res[1].start || res[2].start ||
+			    res[3].start || res[4].start || res[5].start)
+				continue;
+		}
+
 		pdev_sort_resources(dev, &head);
 	}