1 files changed, 84 insertions, 37 deletions

diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index b7ff59d3db8..3f746c8eb0d 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -12,7 +12,6 @@
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
-#include <linux/init.h>
 #include <linux/wait.h>
 #include <linux/bitops.h>
 #include <linux/delay.h>
@@ -132,6 +131,7 @@ EXPORT_SYMBOL(tty_port_free_xmit_buf);
  */
 void tty_port_destroy(struct tty_port *port)
 {
+	cancel_work_sync(&port->buf.work);
 	tty_buffer_free_all(port);
 }
 EXPORT_SYMBOL(tty_port_destroy);
@@ -139,6 +139,10 @@ EXPORT_SYMBOL(tty_port_destroy);
 static void tty_port_destructor(struct kref *kref)
 {
 	struct tty_port *port = container_of(kref, struct tty_port, kref);
+
+	/* check if last port ref was dropped before tty release */
+	if (WARN_ON(port->itty))
+		return;
 	if (port->xmit_buf)
 		free_page((unsigned long)port->xmit_buf);
 	tty_port_destroy(port);
@@ -196,12 +200,24 @@ void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty)
 }
 EXPORT_SYMBOL(tty_port_tty_set);
 
-static void tty_port_shutdown(struct tty_port *port)
+static void tty_port_shutdown(struct tty_port *port, struct tty_struct *tty)
 {
 	mutex_lock(&port->mutex);
-	if (port->ops->shutdown && !port->console &&
-		test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags))
+	if (port->console)
+		goto out;
+
+	if (test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags)) {
+		/*
+		 * Drop DTR/RTS if HUPCL is set. This causes any attached
+		 * modem to hang up the line.
+		 */
+		if (tty && C_HUPCL(tty))
+			tty_port_lower_dtr_rts(port);
+
+		if (port->ops->shutdown)
 			port->ops->shutdown(port);
+	}
+out:
 	mutex_unlock(&port->mutex);
 }
 
@@ -215,24 +231,57 @@ static void tty_port_shutdown(struct tty_port *port)
 
 void tty_port_hangup(struct tty_port *port)
 {
+	struct tty_struct *tty;
 	unsigned long flags;
 
 	spin_lock_irqsave(&port->lock, flags);
 	port->count = 0;
 	port->flags &= ~ASYNC_NORMAL_ACTIVE;
-	if (port->tty) {
-		set_bit(TTY_IO_ERROR, &port->tty->flags);
-		tty_kref_put(port->tty);
-	}
+	tty = port->tty;
+	if (tty)
+		set_bit(TTY_IO_ERROR, &tty->flags);
 	port->tty = NULL;
 	spin_unlock_irqrestore(&port->lock, flags);
+	tty_port_shutdown(port, tty);
+	tty_kref_put(tty);
 	wake_up_interruptible(&port->open_wait);
 	wake_up_interruptible(&port->delta_msr_wait);
-	tty_port_shutdown(port);
 }
 EXPORT_SYMBOL(tty_port_hangup);
 
 /**
+ * tty_port_tty_hangup - helper to hang up a tty
+ *
+ * @port: tty port
+ * @check_clocal: hang only ttys with CLOCAL unset?
+ */
+void tty_port_tty_hangup(struct tty_port *port, bool check_clocal)
+{
+	struct tty_struct *tty = tty_port_tty_get(port);
+
+	if (tty && (!check_clocal || !C_CLOCAL(tty)))
+		tty_hangup(tty);
+	tty_kref_put(tty);
+}
+EXPORT_SYMBOL_GPL(tty_port_tty_hangup);
+
+/**
+ * tty_port_tty_wakeup - helper to wake up a tty
+ *
+ * @port: tty port
+ */
+void tty_port_tty_wakeup(struct tty_port *port)
+{
+	struct tty_struct *tty = tty_port_tty_get(port);
+
+	if (tty) {
+		tty_wakeup(tty);
+		tty_kref_put(tty);
+	}
+}
+EXPORT_SYMBOL_GPL(tty_port_tty_wakeup);
+
+/**
  *	tty_port_carrier_raised	-	carrier raised check
  *	@port: tty port
  *
@@ -350,7 +399,7 @@ int tty_port_block_til_ready(struct tty_port *port,
 
 	while (1) {
 		/* Indicate we are open */
-		if (tty->termios.c_cflag & CBAUD)
+		if (C_BAUD(tty) && test_bit(ASYNCB_INITIALIZED, &port->flags))
 			tty_port_raise_dtr_rts(port);
 
 		prepare_to_wait(&port->open_wait, &wait, TASK_INTERRUPTIBLE);
@@ -395,6 +444,20 @@ int tty_port_block_til_ready(struct tty_port *port,
 }
 EXPORT_SYMBOL(tty_port_block_til_ready);
 
+static void tty_port_drain_delay(struct tty_port *port, struct tty_struct *tty)
+{
+	unsigned int bps = tty_get_baud_rate(tty);
+	long timeout;
+
+	if (bps > 1200) {
+		timeout = (HZ * 10 * port->drain_delay) / bps;
+		timeout = max_t(long, timeout, HZ / 10);
+	} else {
+		timeout = 2 * HZ;
+	}
+	schedule_timeout_interruptible(timeout);
+}
+
 int tty_port_close_start(struct tty_port *port,
 				struct tty_struct *tty, struct file *filp)
 {
@@ -420,41 +483,25 @@ int tty_port_close_start(struct tty_port *port,
 
 	if (port->count) {
 		spin_unlock_irqrestore(&port->lock, flags);
-		if (port->ops->drop)
-			port->ops->drop(port);
 		return 0;
 	}
 	set_bit(ASYNCB_CLOSING, &port->flags);
 	tty->closing = 1;
 	spin_unlock_irqrestore(&port->lock, flags);
-	/* Don't block on a stalled port, just pull the chain */
-	if (tty->flow_stopped)
-		tty_driver_flush_buffer(tty);
-	if (test_bit(ASYNCB_INITIALIZED, &port->flags) &&
-			port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
-		tty_wait_until_sent_from_close(tty, port->closing_wait);
-	if (port->drain_delay) {
-		unsigned int bps = tty_get_baud_rate(tty);
-		long timeout;
-
-		if (bps > 1200)
-			timeout = max_t(long,
-				(HZ * 10 * port->drain_delay) / bps, HZ / 10);
-		else
-			timeout = 2 * HZ;
-		schedule_timeout_interruptible(timeout);
+
+	if (test_bit(ASYNCB_INITIALIZED, &port->flags)) {
+		/* Don't block on a stalled port, just pull the chain */
+		if (tty->flow_stopped)
+			tty_driver_flush_buffer(tty);
+		if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
+			tty_wait_until_sent_from_close(tty, port->closing_wait);
+		if (port->drain_delay)
+			tty_port_drain_delay(port, tty);
 	}
 	/* Flush the ldisc buffering */
 	tty_ldisc_flush(tty);
 
-	/* Drop DTR/RTS if HUPCL is set. This causes any attached modem to
-	   hang up the line */
-	if (tty->termios.c_cflag & HUPCL)
-		tty_port_lower_dtr_rts(port);
-
-	/* Don't call port->drop for the last reference. Callers will want
-	   to drop the last active reference in ->shutdown() or the tty
-	   shutdown path */
+	/* Report to caller this is the last port reference */
 	return 1;
 }
 EXPORT_SYMBOL(tty_port_close_start);
@@ -486,7 +533,7 @@ void tty_port_close(struct tty_port *port, struct tty_struct *tty,
 {
 	if (tty_port_close_start(port, tty, filp) == 0)
 		return;
-	tty_port_shutdown(port);
+	tty_port_shutdown(port, tty);
 	set_bit(TTY_IO_ERROR, &tty->flags);
 	tty_port_close_end(port, tty);
 	tty_port_tty_set(port, NULL);