x86/PCI: Allocate resources on a per-bus basis for hot-adding root buses

Previously pcibios_allocate_resources() allocated resources at boot-time
for all PCI devices using for_each_pci_dev().  This patch changes
pcibios_allocate_resources() so we can specify a bus, so we can do
similar allocation when hot-adding a root bus.

[bhelgaas: changelog]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

arch/x86/pci/i386.c

@@ -215,16 +215,15 @@ static void __init pcibios_allocate_bridge_resources(struct pci_dev *dev)
 	}
 }
 
-static void __init pcibios_allocate_bus_resources(struct list_head *bus_list)
+static void __init pcibios_allocate_bus_resources(struct pci_bus *bus)
 {
-	struct pci_bus *bus;
+	struct pci_bus *child;
 
 	/* Depth-First Search on bus tree */
-	list_for_each_entry(bus, bus_list, node) {
 	if (bus->self)
 		pcibios_allocate_bridge_resources(bus->self);
-		pcibios_allocate_bus_resources(&bus->children);
-	}
+	list_for_each_entry(child, &bus->children, node)
+		pcibios_allocate_bus_resources(child);
 }
 
 struct pci_check_idx_range {
@@ -285,12 +284,18 @@ static void __init pcibios_allocate_dev_resources(struct pci_dev *dev, int pass)
 	}
 }
 
-static void __init pcibios_allocate_resources(int pass)
+static void __init pcibios_allocate_resources(struct pci_bus *bus, int pass)
 {
-	struct pci_dev *dev = NULL;
+	struct pci_dev *dev;
+	struct pci_bus *child;
 
-	for_each_pci_dev(dev)
+	list_for_each_entry(dev, &bus->devices, bus_list) {
 		pcibios_allocate_dev_resources(dev, pass);
+
+		child = dev->subordinate;
+		if (child)
+			pcibios_allocate_resources(child, pass);
+	}
 }
 
 static int __init pcibios_assign_resources(void)
@@ -323,10 +328,17 @@ static int __init pcibios_assign_resources(void)
 
 void __init pcibios_resource_survey(void)
 {
+	struct pci_bus *bus;
+
 	DBG("PCI: Allocating resources\n");
-	pcibios_allocate_bus_resources(&pci_root_buses);
-	pcibios_allocate_resources(0);
-	pcibios_allocate_resources(1);
+
+	list_for_each_entry(bus, &pci_root_buses, node)
+		pcibios_allocate_bus_resources(bus);
+
+	list_for_each_entry(bus, &pci_root_buses, node)
+		pcibios_allocate_resources(bus, 0);
+	list_for_each_entry(bus, &pci_root_buses, node)
+		pcibios_allocate_resources(bus, 1);
 
 	e820_reserve_resources_late();
 	/*