X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=drivers%2Ftty%2Ftty_ldisc.c;h=3737f55272d2c1184463edc3714f89fb2724730e;hb=28023d2a8e9121b1b06c3b46e523c3c7a3e8b530;hp=1dbe27824220266e1dd23b71bab7f6edadae32d1;hpb=fae76e9adfa450f4c2dd5773265eb3c811a9c484;p=firefly-linux-kernel-4.4.55.git

diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index 1dbe27824220..3737f55272d2 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -393,33 +393,21 @@ static void __lockfunc tty_ldisc_unlock_pair(struct tty_struct *tty,
 		__tty_ldisc_unlock(tty2);
 }
 
-static void __lockfunc tty_ldisc_enable_pair(struct tty_struct *tty,
-					     struct tty_struct *tty2)
-{
-	clear_bit(TTY_LDISC_HALTED, &tty->flags);
-	if (tty2)
-		clear_bit(TTY_LDISC_HALTED, &tty2->flags);
-
-	tty_ldisc_unlock_pair(tty, tty2);
-}
-
 /**
  *	tty_ldisc_flush	-	flush line discipline queue
  *	@tty: tty
  *
- *	Flush the line discipline queue (if any) for this tty. If there
- *	is no line discipline active this is a no-op.
+ *	Flush the line discipline queue (if any) and the tty flip buffers
+ *	for this tty.
  */
 
 void tty_ldisc_flush(struct tty_struct *tty)
 {
 	struct tty_ldisc *ld = tty_ldisc_ref(tty);
-	if (ld) {
-		if (ld->ops->flush_buffer)
-			ld->ops->flush_buffer(tty);
+
+	tty_buffer_flush(tty, ld);
+	if (ld)
 		tty_ldisc_deref(ld);
-	}
-	tty_buffer_flush(tty);
 }
 EXPORT_SYMBOL_GPL(tty_ldisc_flush);
 
@@ -535,14 +523,13 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
 {
 	int retval;
 	struct tty_ldisc *old_ldisc, *new_ldisc;
-	struct tty_struct *o_tty = tty->link;
 
 	new_ldisc = tty_ldisc_get(tty, ldisc);
 	if (IS_ERR(new_ldisc))
 		return PTR_ERR(new_ldisc);
 
 	tty_lock(tty);
-	retval = tty_ldisc_lock_pair_timeout(tty, o_tty, 5 * HZ);
+	retval = tty_ldisc_lock(tty, 5 * HZ);
 	if (retval) {
 		tty_ldisc_put(new_ldisc);
 		tty_unlock(tty);
@@ -554,7 +541,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
 	 */
 
 	if (tty->ldisc->ops->num == ldisc) {
-		tty_ldisc_enable_pair(tty, o_tty);
+		tty_ldisc_unlock(tty);
 		tty_ldisc_put(new_ldisc);
 		tty_unlock(tty);
 		return 0;
@@ -565,7 +552,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
 	if (test_bit(TTY_HUPPED, &tty->flags)) {
 		/* We were raced by the hangup method. It will have stomped
 		   the ldisc data and closed the ldisc down */
-		tty_ldisc_enable_pair(tty, o_tty);
+		tty_ldisc_unlock(tty);
 		tty_ldisc_put(new_ldisc);
 		tty_unlock(tty);
 		return -EIO;
@@ -585,8 +572,11 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
 		tty_ldisc_restore(tty, old_ldisc);
 	}
 
-	if (tty->ldisc->ops->num != old_ldisc->ops->num && tty->ops->set_ldisc)
+	if (tty->ldisc->ops->num != old_ldisc->ops->num && tty->ops->set_ldisc) {
+		down_read(&tty->termios_rwsem);
 		tty->ops->set_ldisc(tty);
+		up_read(&tty->termios_rwsem);
+	}
 
 	/* At this point we hold a reference to the new ldisc and a
 	   reference to the old ldisc, or we hold two references to
@@ -599,13 +589,11 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
 	/*
 	 *	Allow ldisc referencing to occur again
 	 */
-	tty_ldisc_enable_pair(tty, o_tty);
+	tty_ldisc_unlock(tty);
 
 	/* Restart the work queue in case no characters kick it off. Safe if
 	   already running */
 	schedule_work(&tty->port->buf.work);
-	if (o_tty)
-		schedule_work(&o_tty->port->buf.work);
 
 	tty_unlock(tty);
 	return retval;