diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index e4e18adb57..9a1ea9b4ea 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -257,11 +257,9 @@ static void module_list_active(struct module_list *list)
 
 static char *get_up_path(const char *path)
 {
-	int i;
 	struct strbuf sb = STRBUF_INIT;
 
-	for (i = count_slashes(path); i; i--)
-		strbuf_addstr(&sb, "../");
+	strbuf_addstrings(&sb, "../", count_slashes(path));
 
 	/*
 	 * Check if 'path' ends with slash or not
diff --git a/json-writer.c b/json-writer.c
index 005c820aa4..25b9201f9c 100644
--- a/json-writer.c
+++ b/json-writer.c
@@ -46,10 +46,7 @@ static void append_quoted_string(struct strbuf *out, const char *in)
 
 static void indent_pretty(struct json_writer *jw)
 {
-	int k;
-
-	for (k = 0; k < jw->open_stack.len; k++)
-		strbuf_addstr(&jw->json, "  ");
+	strbuf_addstrings(&jw->json, "  ", jw->open_stack.len);
 }
 
 /*
diff --git a/strbuf.c b/strbuf.c
index 0d929e4e19..e3ca9b1ee9 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -313,6 +313,15 @@ void strbuf_add(struct strbuf *sb, const void *data, size_t len)
 	strbuf_setlen(sb, sb->len + len);
 }
 
+void strbuf_addstrings(struct strbuf *sb, const char *s, size_t n)
+{
+	size_t len = strlen(s);
+
+	strbuf_grow(sb, st_mult(len, n));
+	for (size_t i = 0; i < n; i++)
+		strbuf_add(sb, s, len);
+}
+
 void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2)
 {
 	strbuf_grow(sb, sb2->len);
diff --git a/strbuf.h b/strbuf.h
index 97fa4a3d01..003f880ff7 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -310,6 +310,11 @@ static inline void strbuf_addstr(struct strbuf *sb, const char *s)
 	strbuf_add(sb, s, strlen(s));
 }
 
+/**
+ * Add a NUL-terminated string the specified number of times to the buffer.
+ */
+void strbuf_addstrings(struct strbuf *sb, const char *s, size_t n);
+
 /**
  * Copy the contents of another buffer at the end of the current one.
  */