ipcns: Add a  limit on the number of ipc namespaces

Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index d10e54f..848e579 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -58,6 +58,7 @@
 
 	/* user_ns which owns the ipc ns */
 	struct user_namespace *user_ns;
+	struct ucounts *ucounts;
 
 	struct ns_common ns;
 };
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index f9df7dd..e1d6721 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -28,6 +28,7 @@
 	UCOUNT_USER_NAMESPACES,
 	UCOUNT_PID_NAMESPACES,
 	UCOUNT_UTS_NAMESPACES,
+	UCOUNT_IPC_NAMESPACES,
 	UCOUNT_COUNTS,
 };