tty: Add diagnostic for halted line discipline

Flip buffer work must not be scheduled by the line discipline
after the line discipline has been halted; issue warning.

Note: drivers can still schedule flip buffer work.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/tty.h b/include/linux/tty.h
index d3548f871968..66ae020e8a98 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -315,6 +315,7 @@ struct tty_file_private {
 #define TTY_NO_WRITE_SPLIT      17      /* Preserve write boundaries to driver */
 #define TTY_HUPPED              18      /* Post driver->hangup() */
 #define TTY_HUPPING             21      /* ->hangup() in progress */
+#define TTY_LDISC_HALTED        22      /* Line discipline is halted */
 
 #define TTY_WRITE_FLUSH(tty) tty_write_flush((tty))