diff --git a/lib/flex_array.c b/lib/flex_array.c
index 6948a66..2eed22f 100644
--- a/lib/flex_array.c
+++ b/lib/flex_array.c
@@ -90,8 +90,8 @@
 {
 	struct flex_array *ret;
 	int elems_per_part = 0;
-	int reciprocal_elems = 0;
 	int max_size = 0;
+	struct reciprocal_value reciprocal_elems = { 0 };
 
 	if (element_size) {
 		elems_per_part = FLEX_ARRAY_ELEMENTS_PER_PART(element_size);
@@ -119,6 +119,11 @@
 static int fa_element_to_part_nr(struct flex_array *fa,
 					unsigned int element_nr)
 {
+	/*
+	 * if element_size == 0 we don't get here, so we never touch
+	 * the zeroed fa->reciprocal_elems, which would yield invalid
+	 * results
+	 */
 	return reciprocal_divide(element_nr, fa->reciprocal_elems);
 }