[POWERPC] pcibus_to_node fixes

of_node_to_nid returns -1 if the associativity cannot be found. This
means pcibus_to_cpumask has to be careful not to pass a negative index into
node_to_cpumask.

Since pcibus_to_node could be used a lot, and of_node_to_nid is slow (it
walks a list doing strcmps), lets also cache the node in the
pci_controller struct.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kernel/pci_64.c b/arch/powerpc/kernel/pci_64.c
index 74dc766..5ad87c4 100644
--- a/arch/powerpc/kernel/pci_64.c
+++ b/arch/powerpc/kernel/pci_64.c
@@ -227,8 +227,10 @@
 	pci_setup_pci_controller(phb);
 	phb->arch_data = dev;
 	phb->is_dynamic = mem_init_done;
-	if (dev)
+	if (dev) {
+		PHB_SET_NODE(phb, of_node_to_nid(dev));
 		add_linux_pci_domain(dev, phb);
+	}
 	return phb;
 }
 
@@ -1415,3 +1417,12 @@
 
 	return -EOPNOTSUPP;
 }
+
+#ifdef CONFIG_NUMA
+int pcibus_to_node(struct pci_bus *bus)
+{
+	struct pci_controller *phb = pci_bus_to_host(bus);
+	return phb->node;
+}
+EXPORT_SYMBOL(pcibus_to_node);
+#endif