uapi/fcntl: add FD_PIDFS_ROOT

Add a special file descriptor indicating the root of the pidfs
filesystem.

Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h
index a5bebe7c4400800420924985da8dbb4b93a06119..f291ab4f94ebccacfd966de03a08c4948aa89e60 100644 (file)
--- a/include/uapi/linux/fcntl.h
+++ b/include/uapi/linux/fcntl.h
@@ -110,6 +110,7 @@
 #define PIDFD_SELF_THREAD              -10000 /* Current thread. */
 #define PIDFD_SELF_THREAD_GROUP                -10001 /* Current thread group leader. */
 
+#define FD_PIDFS_ROOT                  -10002 /* Root of the pidfs filesystem */
 #define FD_INVALID                     -10009 /* Invalid file descriptor: -10000 - EBADF = -10009 */
 
 /* Generic flags for the *at(2) family of syscalls. */