diff --git a/builtin-log.c b/builtin-log.c
index 4a4890aca0..ffc269a122 100644
--- a/builtin-log.c
+++ b/builtin-log.c
@@ -435,7 +435,6 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 	rev.ignore_merges = 1;
 	rev.diffopt.msg_sep = "";
 	rev.diffopt.recursive = 1;
-	rev.subject_prefix = "PATCH";
 
 	rev.extra_headers = extra_headers;
 
diff --git a/revision.c b/revision.c
index 486393cb08..37f1eab9e5 100644
--- a/revision.c
+++ b/revision.c
@@ -567,6 +567,7 @@ void init_revisions(struct rev_info *revs, const char *prefix)
 	revs->min_age = -1;
 	revs->skip_count = -1;
 	revs->max_count = -1;
+	revs->subject_prefix = "PATCH";
 
 	revs->prune_fn = NULL;
 	revs->prune_data = NULL;