USB: ssu100: fix port-data memory leak

Fix port-data memory leak by replacing attach and release with
port_probe and port_remove.

Since commit 0998d0631001288 (device-core: Ensure drvdata = NULL when no
driver is bound) the port private data is no longer freed at release as
it is no longer accessible.

Compile-only tested.

Cc: <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/ssu100.c

@@ -67,13 +67,6 @@ struct ssu100_port_private {
 	struct async_icount icount;
 };
 
-static void ssu100_release(struct usb_serial *serial)
-{
-	struct ssu100_port_private *priv = usb_get_serial_port_data(*serial->port);
-
-	kfree(priv);
-}
-
 static inline int ssu100_control_msg(struct usb_device *dev,
 				     u8 request, u16 data, u16 index)
 {
@@ -441,22 +434,34 @@ static int ssu100_ioctl(struct tty_struct *tty,
 }
 
 static int ssu100_attach(struct usb_serial *serial)
+{
+	return ssu100_initdevice(serial->dev);
+}
+
+static int ssu100_port_probe(struct usb_serial_port *port)
 {
 	struct ssu100_port_private *priv;
-	struct usb_serial_port *port = *serial->port;
 
 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
-	if (!priv) {
-		dev_err(&port->dev, "%s- kmalloc(%Zd) failed.\n", __func__,
-			sizeof(*priv));
+	if (!priv)
 		return -ENOMEM;
-	}
 
 	spin_lock_init(&priv->status_lock);
 	init_waitqueue_head(&priv->delta_msr_wait);
+
 	usb_set_serial_port_data(port, priv);
 
-	return ssu100_initdevice(serial->dev);
+	return 0;
+}
+
+static int ssu100_port_remove(struct usb_serial_port *port)
+{
+	struct ssu100_port_private *priv;
+
+	priv = usb_get_serial_port_data(port);
+	kfree(priv);
+
+	return 0;
 }
 
 static int ssu100_tiocmget(struct tty_struct *tty)
@@ -647,7 +652,8 @@ static struct usb_serial_driver ssu100_device = {
 	.open		     = ssu100_open,
 	.close		     = ssu100_close,
 	.attach              = ssu100_attach,
-	.release             = ssu100_release,
+	.port_probe          = ssu100_port_probe,
+	.port_remove         = ssu100_port_remove,
 	.dtr_rts             = ssu100_dtr_rts,
 	.process_read_urb    = ssu100_process_read_urb,
 	.tiocmget            = ssu100_tiocmget,