1 files changed, 7 insertions, 2 deletions

diff --git a/include/linux/tty.h b/include/linux/tty.h
index f9c13c83790c..1488d8c81aac 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -226,8 +226,11 @@ struct tty_struct {
         struct tty_driver *driver;
         const struct tty_operations *ops;
         int index;
-        /* The ldisc objects are protected by tty_ldisc_lock at the moment */
-        struct tty_ldisc ldisc;
+
+        /* Protects ldisc changes: Lock tty not pty */
+        struct mutex ldisc_mutex;
+        struct tty_ldisc *ldisc;
+
         struct mutex termios_mutex;
         spinlock_t ctrl_lock;
         /* Termios values are protected by the termios mutex */
@@ -314,6 +317,7 @@ struct tty_struct {
 #define TTY_CLOSING             7       /* ->close() in progress */
 #define TTY_LDISC               9       /* Line discipline attached */
 #define TTY_LDISC_CHANGING      10      /* Line discipline changing */
+#define TTY_LDISC_OPEN          11      /* Line discipline is open */
 #define TTY_HW_COOK_OUT         14      /* Hardware can do output cooking */
 #define TTY_HW_COOK_IN          15      /* Hardware can do input cooking */
 #define TTY_PTY_LOCK            16      /* pty private */
@@ -406,6 +410,7 @@ extern int tty_termios_hw_change(struct ktermios *a, struct ktermios *b);
 extern struct tty_ldisc *tty_ldisc_ref(struct tty_struct *);
 extern void tty_ldisc_deref(struct tty_ldisc *);
 extern struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *);
+extern void tty_ldisc_hangup(struct tty_struct *tty);
 extern const struct file_operations tty_ldiscs_proc_fops;
 
 extern void tty_wakeup(struct tty_struct *tty);