diff --git a/reftable/block.c b/reftable/block.c
index 72eb73b380..1663030386 100644
--- a/reftable/block.c
+++ b/reftable/block.c
@@ -302,7 +302,7 @@ static int restart_key_less(size_t idx, void *args)
 
 	result = strbuf_cmp(&a->key, &rkey);
 	strbuf_release(&rkey);
-	return result;
+	return result < 0;
 }
 
 void block_iter_copy_from(struct block_iter *dest, struct block_iter *src)