diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 471a429d7a20..ea979f2bc6db 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -299,7 +299,7 @@ static void pbus_size_io(struct pci_bus *bus)
 
 			if (r->parent || !(r->flags & IORESOURCE_IO))
 				continue;
-			r_size = r->end - r->start + 1;
+			r_size = resource_size(r);
 
 			if (r_size < 0x400)
 				/* Might be re-aligned for ISA */
@@ -350,7 +350,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, unsigned long
 
 			if (r->parent || (r->flags & mask) != type)
 				continue;
-			r_size = r->end - r->start + 1;
+			r_size = resource_size(r);
 			/* For bridges size != alignment */
 			align = resource_alignment(r);
 			order = __ffs(align) - 20;
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index d4b5c690eaa7..2dbd96cce2d8 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -129,7 +129,7 @@ int pci_assign_resource(struct pci_dev *dev, int resno)
 	resource_size_t size, min, align;
 	int ret;
 
-	size = res->end - res->start + 1;
+	size = resource_size(res);
 	min = (res->flags & IORESOURCE_IO) ? PCIBIOS_MIN_IO : PCIBIOS_MIN_MEM;
 
 	align = resource_alignment(res);