1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 7cd56d2b9419..a994129ede55 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -389,6 +389,8 @@ static inline int mtd_write_user_prot_reg(struct mtd_info *mtd, loff_t to,
 static inline int mtd_lock_user_prot_reg(struct mtd_info *mtd, loff_t from,
                                          size_t len)
 {
+        if (!mtd->lock_user_prot_reg)
+                return -EOPNOTSUPP;
         return mtd->lock_user_prot_reg(mtd, from, len);
 }