diff --git a/include/linux/firewire.h b/include/linux/firewire.h
index 584826b..d77f60c 100644
--- a/include/linux/firewire.h
+++ b/include/linux/firewire.h
@@ -307,7 +307,7 @@
 
 struct fw_address_handler {
 	u64 offset;
-	size_t length;
+	u64 length;
 	fw_address_callback_t address_callback;
 	void *callback_data;
 	struct list_head link;