v4.19.13 snapshot.
diff --git a/include/linux/msg.h b/include/linux/msg.h
new file mode 100644
index 0000000..9a972a2
--- /dev/null
+++ b/include/linux/msg.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MSG_H
+#define _LINUX_MSG_H
+
+#include <linux/list.h>
+#include <uapi/linux/msg.h>
+
+/* one msg_msg structure for each message */
+struct msg_msg {
+ struct list_head m_list;
+ long m_type;
+ size_t m_ts; /* message text size */
+ struct msg_msgseg *next;
+ void *security;
+ /* the actual message follows immediately */
+};
+
+#endif /* _LINUX_MSG_H */