uapi/fcntl: add FD_INVALID

Add a marker for an invalid file descriptor.

Link: https://lore.kernel.org/20250624-work-pidfs-fhandle-v2-7-d02a04858fe3@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h
index ba4a698d2f33f2cf2cbf107d937fe63a82d34e53..a5bebe7c4400800420924985da8dbb4b93a06119 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_INVALID                     -10009 /* Invalid file descriptor: -10000 - EBADF = -10009 */
 
 /* Generic flags for the *at(2) family of syscalls. */