diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
index ea923ea..aaa1b5b 100644
--- a/builtin/commit-graph.c
+++ b/builtin/commit-graph.c
@@ -179,7 +179,7 @@ static int write_option_max_new_filters(const struct option *opt,
 }
 
 static int git_commit_graph_write_config(const char *var, const char *value,
-					 void *UNUSED(cb))
+					 void *cb UNUSED)
 {
 	if (!strcmp(var, "commitgraph.maxnewfilters"))
 		write_opts.max_new_filters = git_config_int(var, value);