1 files changed, 18 insertions, 0 deletions

diff --git a/include/linux/tty.h b/include/linux/tty.h
index c75d886b0307..189ca80494d1 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -258,6 +258,7 @@ struct tty_struct {
         unsigned char warned:1;
         unsigned char ctrl_status;      /* ctrl_lock */
         unsigned int receive_room;      /* Bytes free for queue */
+        int flow_change;
 
         struct tty_struct *link;
         struct fasync_struct *fasync;
@@ -318,6 +319,21 @@ struct tty_file_private {
 
 #define TTY_WRITE_FLUSH(tty) tty_write_flush((tty))
 
+/* Values for tty->flow_change */
+#define TTY_THROTTLE_SAFE 1
+#define TTY_UNTHROTTLE_SAFE 2
+
+static inline void __tty_set_flow_change(struct tty_struct *tty, int val)
+{
+        tty->flow_change = val;
+}
+
+static inline void tty_set_flow_change(struct tty_struct *tty, int val)
+{
+        tty->flow_change = val;
+        smp_mb();
+}
+
 #ifdef CONFIG_TTY
 extern void console_init(void);
 extern void tty_kref_put(struct tty_struct *tty);
@@ -400,6 +416,8 @@ extern int tty_write_room(struct tty_struct *tty);
 extern void tty_driver_flush_buffer(struct tty_struct *tty);
 extern void tty_throttle(struct tty_struct *tty);
 extern void tty_unthrottle(struct tty_struct *tty);
+extern int tty_throttle_safe(struct tty_struct *tty);
+extern int tty_unthrottle_safe(struct tty_struct *tty);
 extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
 extern void tty_driver_remove_tty(struct tty_driver *driver,
                                   struct tty_struct *tty);