USB: belkin_sa: 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.

Note that the write waitqueue was initialised but never used.

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/belkin_sa.c

@@ -45,8 +45,8 @@
 #define DRIVER_DESC "USB Belkin Serial converter driver"
 
 /* function prototypes for a Belkin USB Serial Adapter F5U103 */
-static int  belkin_sa_startup(struct usb_serial *serial);
-static void belkin_sa_release(struct usb_serial *serial);
+static int belkin_sa_port_probe(struct usb_serial_port *port);
+static int belkin_sa_port_remove(struct usb_serial_port *port);
 static int  belkin_sa_open(struct tty_struct *tty,
 			struct usb_serial_port *port);
 static void belkin_sa_close(struct usb_serial_port *port);
@@ -88,8 +88,8 @@ static struct usb_serial_driver belkin_device = {
 	.break_ctl =		belkin_sa_break_ctl,
 	.tiocmget =		belkin_sa_tiocmget,
 	.tiocmset =		belkin_sa_tiocmset,
-	.attach =		belkin_sa_startup,
-	.release =		belkin_sa_release,
+	.port_probe =		belkin_sa_port_probe,
+	.port_remove =		belkin_sa_port_remove,
 };
 
 static struct usb_serial_driver * const serial_drivers[] = {
@@ -118,17 +118,15 @@ struct belkin_sa_private {
 					    (c), BELKIN_SA_SET_REQUEST_TYPE, \
 					    (v), 0, NULL, 0, WDR_TIMEOUT)
 
-/* do some startup allocations not currently performed by usb_serial_probe() */
-static int belkin_sa_startup(struct usb_serial *serial)
+static int belkin_sa_port_probe(struct usb_serial_port *port)
 {
-	struct usb_device *dev = serial->dev;
+	struct usb_device *dev = port->serial->dev;
 	struct belkin_sa_private *priv;
 
-	/* allocate the private data structure */
 	priv = kmalloc(sizeof(struct belkin_sa_private), GFP_KERNEL);
 	if (!priv)
-		return -1; /* error */
-	/* set initial values for control structures */
+		return -ENOMEM;
+
 	spin_lock_init(&priv->lock);
 	priv->control_state = 0;
 	priv->last_lsr = 0;
@@ -140,18 +138,19 @@ static int belkin_sa_startup(struct usb_serial *serial)
 					le16_to_cpu(dev->descriptor.bcdDevice),
 					priv->bad_flow_control);
 
-	init_waitqueue_head(&serial->port[0]->write_wait);
-	usb_set_serial_port_data(serial->port[0], priv);
+	usb_set_serial_port_data(port, priv);
 
 	return 0;
 }
 
-static void belkin_sa_release(struct usb_serial *serial)
+static int belkin_sa_port_remove(struct usb_serial_port *port)
 {
-	int i;
+	struct belkin_sa_private *priv;
 
-	for (i = 0; i < serial->num_ports; ++i)
-		kfree(usb_get_serial_port_data(serial->port[i]));
+	priv = usb_get_serial_port_data(port);
+	kfree(priv);
+
+	return 0;
 }
 
 static int belkin_sa_open(struct tty_struct *tty,