1 files changed, 42 insertions, 12 deletions

diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index 9f7896a25f1b..d345a6eec4ca 100644
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -1015,7 +1015,7 @@ static void _hso_serial_set_termios(struct tty_struct *tty,
 	struct hso_serial *serial = get_serial_by_tty(tty);
 	struct ktermios *termios;
 
-	if ((!tty) || (!tty->termios) || (!serial)) {
+	if (!serial) {
 		printk(KERN_ERR "%s: no tty structures", __func__);
 		return;
 	}
@@ -1057,14 +1057,14 @@ static void _hso_serial_set_termios(struct tty_struct *tty,
 	termios->c_cflag |= CS8;	/* character size 8 bits */
 
 	/* baud rate 115200 */
-	tty_encode_baud_rate(serial->tty, 115200, 115200);
+	tty_encode_baud_rate(tty, 115200, 115200);
 
 	/*
 	 * Force low_latency on; otherwise the pushes are scheduled;
 	 * this is bad as it opens up the possibility of dropping bytes
 	 * on the floor.  We don't want to drop bytes on the floor. :)
 	 */
-	serial->tty->low_latency = 1;
+	tty->low_latency = 1;
 	return;
 }
 
@@ -1228,6 +1228,7 @@ static int hso_serial_open(struct tty_struct *tty, struct file *filp)
 
 	/* sanity check */
 	if (serial == NULL || serial->magic != HSO_SERIAL_MAGIC) {
+		WARN_ON(1);
 		tty->driver_data = NULL;
 		D1("Failed to open port");
 		return -ENODEV;
@@ -1242,8 +1243,10 @@ static int hso_serial_open(struct tty_struct *tty, struct file *filp)
 	kref_get(&serial->parent->ref);
 
 	/* setup */
+	spin_lock_irq(&serial->serial_lock);
 	tty->driver_data = serial;
-	serial->tty = tty;
+	serial->tty = tty_kref_get(tty);
+	spin_unlock_irq(&serial->serial_lock);
 
 	/* check for port already opened, if not set the termios */
 	serial->open_count++;
@@ -1285,6 +1288,10 @@ static void hso_serial_close(struct tty_struct *tty, struct file *filp)
 
 	D1("Closing serial port");
 
+	/* Open failed, no close cleanup required */
+	if (serial == NULL)
+		return;
+
 	mutex_lock(&serial->parent->mutex);
 	usb_gone = serial->parent->usb_gone;
 
@@ -1297,10 +1304,13 @@ static void hso_serial_close(struct tty_struct *tty, struct file *filp)
 	kref_put(&serial->parent->ref, hso_serial_ref_free);
 	if (serial->open_count <= 0) {
 		serial->open_count = 0;
-		if (serial->tty) {
+		spin_lock_irq(&serial->serial_lock);
+		if (serial->tty == tty) {
 			serial->tty->driver_data = NULL;
 			serial->tty = NULL;
+			tty_kref_put(tty);
 		}
+		spin_unlock_irq(&serial->serial_lock);
 		if (!usb_gone)
 			hso_stop_serial_device(serial->parent);
 		tasklet_kill(&serial->unthrottle_tasklet);
@@ -1653,6 +1663,7 @@ static void hso_std_serial_write_bulk_callback(struct urb *urb)
 {
 	struct hso_serial *serial = urb->context;
 	int status = urb->status;
+	struct tty_struct *tty;
 
 	/* sanity check */
 	if (!serial) {
@@ -1662,14 +1673,18 @@ static void hso_std_serial_write_bulk_callback(struct urb *urb)
 
 	spin_lock(&serial->serial_lock);
 	serial->tx_urb_used = 0;
+	tty = tty_kref_get(serial->tty);
 	spin_unlock(&serial->serial_lock);
 	if (status) {
 		log_usb_status(status, __func__);
+		tty_kref_put(tty);
 		return;
 	}
 	hso_put_activity(serial->parent);
-	if (serial->tty)
-		tty_wakeup(serial->tty);
+	if (tty) {
+		tty_wakeup(tty);
+		tty_kref_put(tty);
+	}
 	hso_kick_transmit(serial);
 
 	D1(" ");
@@ -1706,6 +1721,7 @@ static void ctrl_callback(struct urb *urb)
 	struct hso_serial *serial = urb->context;
 	struct usb_ctrlrequest *req;
 	int status = urb->status;
+	struct tty_struct *tty;
 
 	/* sanity check */
 	if (!serial)
@@ -1713,9 +1729,11 @@ static void ctrl_callback(struct urb *urb)
 
 	spin_lock(&serial->serial_lock);
 	serial->tx_urb_used = 0;
+	tty = tty_kref_get(serial->tty);
 	spin_unlock(&serial->serial_lock);
 	if (status) {
 		log_usb_status(status, __func__);
+		tty_kref_put(tty);
 		return;
 	}
 
@@ -1734,25 +1752,31 @@ static void ctrl_callback(struct urb *urb)
 		spin_unlock(&serial->serial_lock);
 	} else {
 		hso_put_activity(serial->parent);
-		if (serial->tty)
-			tty_wakeup(serial->tty);
+		if (tty)
+			tty_wakeup(tty);
 		/* response to a write command */
 		hso_kick_transmit(serial);
 	}
+	tty_kref_put(tty);
 }
 
 /* handle RX data for serial port */
 static int put_rxbuf_data(struct urb *urb, struct hso_serial *serial)
 {
-	struct tty_struct *tty = serial->tty;
+	struct tty_struct *tty;
 	int write_length_remaining = 0;
 	int curr_write_len;
+
 	/* Sanity check */
 	if (urb == NULL || serial == NULL) {
 		D1("serial = NULL");
 		return -2;
 	}
 
+	spin_lock(&serial->serial_lock);
+	tty = tty_kref_get(serial->tty);
+	spin_unlock(&serial->serial_lock);
+
 	/* Push data to tty */
 	if (tty) {
 		write_length_remaining = urb->actual_length -
@@ -1774,6 +1798,7 @@ static int put_rxbuf_data(struct urb *urb, struct hso_serial *serial)
 		serial->curr_rx_urb_offset = 0;
 		serial->rx_urb_filled[hso_urb_to_index(serial, urb)] = 0;
 	}
+	tty_kref_put(tty);
 	return write_length_remaining;
 }
 
@@ -2786,15 +2811,20 @@ static void hso_serial_ref_free(struct kref *ref)
 static void hso_free_interface(struct usb_interface *interface)
 {
 	struct hso_serial *hso_dev;
+	struct tty_struct *tty;
 	int i;
 
 	for (i = 0; i < HSO_SERIAL_TTY_MINORS; i++) {
 		if (serial_table[i]
 		    && (serial_table[i]->interface == interface)) {
 			hso_dev = dev2ser(serial_table[i]);
-			if (hso_dev->tty)
-				tty_hangup(hso_dev->tty);
+			spin_lock_irq(&hso_dev->serial_lock);
+			tty = tty_kref_get(hso_dev->tty);
+			spin_unlock_irq(&hso_dev->serial_lock);
+			if (tty)
+				tty_hangup(tty);
 			mutex_lock(&hso_dev->parent->mutex);
+			tty_kref_put(tty);
 			hso_dev->parent->usb_gone = 1;
 			mutex_unlock(&hso_dev->parent->mutex);
 			kref_put(&serial_table[i]->ref, hso_serial_ref_free);