PCI: Assign resources for hot-added host bridge more aggressively

When hot-adding an ACPI host bridge, use
pci_assign_unassigned_root_bus_resources() instead of
pci_assign_unassigned_bus_resources().

The former is more aggressive and will release and reassign existing
resources if necessary.  This is safe at hot-add time because no drivers
are bound to devices below the new host bridge yet.

[bhelgaas: changelog, split __init changes out for reviewability]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/acpi/pci_root.c

@@ -526,7 +526,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
 
 	if (system_state != SYSTEM_BOOTING) {
 		pcibios_resource_survey_bus(root->bus);
-		pci_assign_unassigned_bus_resources(root->bus);
+		pci_assign_unassigned_root_bus_resources(root->bus);
 	}
 
 	pci_bus_add_devices(root->bus);

drivers/pci/setup-bus.c

@@ -1395,7 +1395,7 @@ static enum enable_type pci_realloc_detect(struct pci_bus *bus,
  * second  and later try will clear small leaf bridge res
  * will stop till to the max  deepth if can not find good one
  */
-static void pci_assign_unassigned_root_bus_resources(struct pci_bus *bus)
+void pci_assign_unassigned_root_bus_resources(struct pci_bus *bus)
 {
 	LIST_HEAD(realloc_head); /* list of resources that
 					want additional resources */

include/linux/pci.h

@@ -1003,6 +1003,7 @@ 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 pci_assign_unassigned_root_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 *),