diff --git a/lib/device/dev-cache.c b/lib/device/dev-cache.c
index ca1f1d56c..a87042738 100644
--- a/lib/device/dev-cache.c
+++ b/lib/device/dev-cache.c
@@ -298,17 +298,15 @@ int dev_cache_init(void)
 	return 0;
 }
 
-iterate_fn _check_closed(void *data)
+void _check_closed(struct device *dev)
 {
-	struct device *dev = (struct device *) data;
-
 	if (dev->fd >= 0)
 		log_err("Device '%s' has been left open.", dev_name(dev));
 }
 
 static inline void _check_for_open_devices(void)
 {
-	hash_iterate(_cache.names, _check_closed);
+	hash_iterate(_cache.names, (iterate_fn)_check_closed);
 }
 
 void dev_cache_exit(void)