diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index acad110..1dbe074 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -108,6 +108,7 @@
 
 extern int bitmap_scnprintf(char *buf, unsigned int len,
 			const unsigned long *src, int nbits);
+extern int bitmap_scnprintf_len(unsigned int len);
 extern int __bitmap_parse(const char *buf, unsigned int buflen, int is_user,
 			unsigned long *dst, int nbits);
 extern int bitmap_parse_user(const char __user *ubuf, unsigned int ulen,