diff --git a/fs/namespace.c b/fs/namespace.c
index 8e0f852be775..141bc96ec875 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1688,8 +1688,12 @@ static inline bool may_mount(void)
 }
 
 #ifdef	CONFIG_MANDATORY_FILE_LOCKING
-static inline bool may_mandlock(void)
+static bool may_mandlock(void)
 {
+	pr_warn_once("======================================================\n"
+		     "WARNING: the mand mount option is being deprecated and\n"
+		     "         will be removed in v5.15!\n"
+		     "======================================================\n");
 	return capable(CAP_SYS_ADMIN);
 }
 #else