diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 2cd07cc..22d2115 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -118,6 +118,10 @@
 int adjust_resource(struct resource *res, resource_size_t start,
 		    resource_size_t size);
 resource_size_t resource_alignment(struct resource *res);
+static inline resource_size_t resource_size(struct resource *res)
+{
+	return res->end - res->start + 1;
+}
 
 /* Convenience shorthand with allocation */
 #define request_region(start,n,name)	__request_region(&ioport_resource, (start), (n), (name))