4 files changed, 15 insertions, 21 deletions

diff --git a/arch/um/Kconfig.common b/arch/um/Kconfig.common
index 648121b..bceee66 100644
--- a/arch/um/Kconfig.common
+++ b/arch/um/Kconfig.common
@@ -12,6 +12,7 @@ config UML
 	select GENERIC_CPU_DEVICES
 	select GENERIC_IO
 	select GENERIC_CLOCKEVENTS
+	select TTY # Needed for line.c
 
 config MMU
 	bool
diff --git a/arch/um/drivers/chan.h b/arch/um/drivers/chan.h
index 02b5a76..78f1b89 100644
--- a/arch/um/drivers/chan.h
+++ b/arch/um/drivers/chan.h
@@ -27,8 +27,7 @@ struct chan {
 	void *data;
 };
 
-extern void chan_interrupt(struct line *line,
-			   struct tty_struct *tty, int irq);
+extern void chan_interrupt(struct line *line, int irq);
 extern int parse_chan_pair(char *str, struct line *line, int device,
 			   const struct chan_opts *opts, char **error_out);
 extern int write_chan(struct chan *chan, const char *buf, int len,
diff --git a/arch/um/drivers/chan_kern.c b/arch/um/drivers/chan_kern.c
index e9a0abc..15c553c 100644
--- a/arch/um/drivers/chan_kern.c
+++ b/arch/um/drivers/chan_kern.c
@@ -81,12 +81,6 @@ static const struct chan_ops not_configged_ops = {
 };
 #endif /* CONFIG_NOCONFIG_CHAN */
 
-static void tty_receive_char(struct tty_struct *tty, char ch)
-{
-	if (tty)
-		tty_insert_flip_char(tty, ch, TTY_NORMAL);
-}
-
 static int open_one_chan(struct chan *chan)
 {
 	int fd, err;
@@ -137,11 +131,9 @@ void chan_enable_winch(struct chan *chan, struct tty_struct *tty)
 static void line_timer_cb(struct work_struct *work)
 {
 	struct line *line = container_of(work, struct line, task.work);
-	struct tty_struct *tty = tty_port_tty_get(&line->port);
 
 	if (!line->throttled)
-		chan_interrupt(line, tty, line->driver->read_irq);
-	tty_kref_put(tty);
+		chan_interrupt(line, line->driver->read_irq);
 }
 
 int enable_chan(struct line *line)
@@ -552,8 +544,9 @@ int parse_chan_pair(char *str, struct line *line, int device,
 	return 0;
 }
 
-void chan_interrupt(struct line *line, struct tty_struct *tty, int irq)
+void chan_interrupt(struct line *line, int irq)
 {
+	struct tty_port *port = &line->port;
 	struct chan *chan = line->chan_in;
 	int err;
 	char c;
@@ -562,21 +555,24 @@ void chan_interrupt(struct line *line, struct tty_struct *tty, int irq)
 		goto out;
 
 	do {
-		if (tty && !tty_buffer_request_room(tty, 1)) {
+		if (!tty_buffer_request_room(port, 1)) {
 			schedule_delayed_work(&line->task, 1);
 			goto out;
 		}
 		err = chan->ops->read(chan->fd, &c, chan->data);
 		if (err > 0)
-			tty_receive_char(tty, c);
+			tty_insert_flip_char(port, c, TTY_NORMAL);
 	} while (err > 0);
 
 	if (err == 0)
 		reactivate_fd(chan->fd, irq);
 	if (err == -EIO) {
 		if (chan->primary) {
-			if (tty != NULL)
+			struct tty_struct *tty = tty_port_tty_get(&line->port);
+			if (tty != NULL) {
 				tty_hangup(tty);
+				tty_kref_put(tty);
+			}
 			if (line->chan_out != chan)
 				close_one_chan(line->chan_out, 1);
 		}
@@ -585,6 +581,5 @@ void chan_interrupt(struct line *line, struct tty_struct *tty, int irq)
 			return;
 	}
  out:
-	if (tty)
-		tty_flip_buffer_push(tty);
+	tty_flip_buffer_push(port);
 }
diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c
index 9ffc28b..f1b3857 100644
--- a/arch/um/drivers/line.c
+++ b/arch/um/drivers/line.c
@@ -19,11 +19,10 @@ static irqreturn_t line_interrupt(int irq, void *data)
 {
 	struct chan *chan = data;
 	struct line *line = chan->line;
-	struct tty_struct *tty = tty_port_tty_get(&line->port);
 
 	if (line)
-		chan_interrupt(line, tty, irq);
-	tty_kref_put(tty);
+		chan_interrupt(line, irq);
+
 	return IRQ_HANDLED;
 }
 
@@ -234,7 +233,7 @@ void line_unthrottle(struct tty_struct *tty)
 	struct line *line = tty->driver_data;
 
 	line->throttled = 0;
-	chan_interrupt(line, tty, line->driver->read_irq);
+	chan_interrupt(line, line->driver->read_irq);
 
 	/*
 	 * Maybe there is enough stuff pending that calling the interrupt