diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 2aa04f29e1de95d89f295c190bb56754ba84efd7..4cb714792bea52ad4ebfac8112c32bcfb3fb2eb4 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -960,13 +960,14 @@ static void __devinit pcibios_fixup_bridge(struct pci_bus *bus)
 		if (i >= 3 && bus->self->transparent)
 			continue;
 
-		/* If we are going to re-assign everything, mark the resource
-		 * as unset and move it down to 0
+		/* If we're going to reassign everything, we can
+		 * shrink the P2P resource to have size as being
+		 * of 0 in order to save space.
 		 */
 		if (pci_has_flag(PCI_REASSIGN_ALL_RSRC)) {
 			res->flags |= IORESOURCE_UNSET;
-			res->end -= res->start;
 			res->start = 0;
+			res->end = -1;
 			continue;
 		}
 
@@ -1228,7 +1229,14 @@ void pcibios_allocate_bus_resources(struct pci_bus *bus)
 		pr_warning("PCI: Cannot allocate resource region "
 			   "%d of PCI bridge %d, will remap\n", i, bus->number);
 	clear_resource:
-		res->start = res->end = 0;
+		/* The resource might be figured out when doing
+		 * reassignment based on the resources required
+		 * by the downstream PCI devices. Here we set
+		 * the size of the resource to be 0 in order to
+		 * save more space.
+		 */
+		res->start = 0;
+		res->end = -1;
 		res->flags = 0;
 	}