PCI: Separate out pci_assign_unassigned_bus_resources()

It is main portion of pci_rescan_bus().

Separate it out and prepare to use it for PCI root bus hot add later.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

drivers/pci/setup-bus.c

@@ -1550,25 +1550,12 @@ void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
 }
 EXPORT_SYMBOL_GPL(pci_assign_unassigned_bridge_resources);
 
-#ifdef CONFIG_HOTPLUG
-/**
- * pci_rescan_bus - scan a PCI bus for devices.
- * @bus: PCI bus to scan
- *
- * Scan a PCI bus and child buses for new devices, adds them,
- * and enables them.
- *
- * Returns the max number of subordinate bus discovered.
- */
-unsigned int __ref pci_rescan_bus(struct pci_bus *bus)
+void pci_assign_unassigned_bus_resources(struct pci_bus *bus)
 {
-	unsigned int max;
 	struct pci_dev *dev;
 	LIST_HEAD(add_list); /* list of resources that
 					want additional resources */
 
-	max = pci_scan_child_bus(bus);
-
 	down_read(&pci_bus_sem);
 	list_for_each_entry(dev, &bus->devices, bus_list)
 		if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||
@@ -1581,6 +1568,24 @@ unsigned int __ref pci_rescan_bus(struct pci_bus *bus)
 	BUG_ON(!list_empty(&add_list));
 
 	pci_enable_bridges(bus);
+}
+
+#ifdef CONFIG_HOTPLUG
+/**
+ * pci_rescan_bus - scan a PCI bus for devices.
+ * @bus: PCI bus to scan
+ *
+ * Scan a PCI bus and child buses for new devices, adds them,
+ * and enables them.
+ *
+ * Returns the max number of subordinate bus discovered.
+ */
+unsigned int __ref pci_rescan_bus(struct pci_bus *bus)
+{
+	unsigned int max;
+
+	max = pci_scan_child_bus(bus);
+	pci_assign_unassigned_bus_resources(bus);
 	pci_bus_add_devices(bus);
 
 	return max;

include/linux/pci.h

@@ -958,6 +958,7 @@ void pci_bus_size_bridges(struct pci_bus *bus);
 int pci_claim_resource(struct pci_dev *, int);
 void pci_assign_unassigned_resources(void);
 void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge);
+void pci_assign_unassigned_bus_resources(struct pci_bus *bus);
 void pdev_enable_device(struct pci_dev *);
 int pci_enable_resources(struct pci_dev *, int mask);
 void pci_fixup_irqs(u8 (*)(struct pci_dev *, u8 *),