diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 16d291e10..a159bfdfa 100755
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -824,11 +824,9 @@ static resource_size_t calculate_memsize(resource_size_t size,
 		size = min_size;
 	if (old_size == 1)
 		old_size = 0;
-	if (size < old_size)
-		size = old_size;
 
-	size = ALIGN(max(size, add_size) + children_add_size, align);
-	return size;
+	size = max(size, add_size) + children_add_size;
+	return ALIGN(max(size, old_size), align);
 }
 
 resource_size_t __weak pcibios_window_alignment(struct pci_bus *bus,