USB: cp210x: fix port-data memory leak

Fix port data memory leak by replacing port private data with serial
private data.

Since commit 0998d063 (device-core: Ensure drvdata = NULL when no
driver is bound) the port private data is no longer freed at
release.

The private data is used to store the control interface number, but as
this is the same for all ports on an interface it should be stored as
usb-serial data anyway.

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/cp210x.c

@@ -162,7 +162,7 @@ static const struct usb_device_id id_table[] = {
 
 MODULE_DEVICE_TABLE(usb, id_table);
 
-struct cp210x_port_private {
+struct cp210x_serial_private {
 	__u8			bInterfaceNumber;
 };
 
@@ -276,7 +276,7 @@ static int cp210x_get_config(struct usb_serial_port *port, u8 request,
 		unsigned int *data, int size)
 {
 	struct usb_serial *serial = port->serial;
-	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
+	struct cp210x_serial_private *spriv = usb_get_serial_data(serial);
 	__le32 *buf;
 	int result, i, length;
 
@@ -292,7 +292,7 @@ static int cp210x_get_config(struct usb_serial_port *port, u8 request,
 	/* Issue the request, attempting to read 'size' bytes */
 	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
 				request, REQTYPE_INTERFACE_TO_HOST, 0x0000,
-				port_priv->bInterfaceNumber, buf, size,
+				spriv->bInterfaceNumber, buf, size,
 				USB_CTRL_GET_TIMEOUT);
 
 	/* Convert data into an array of integers */
@@ -323,7 +323,7 @@ static int cp210x_set_config(struct usb_serial_port *port, u8 request,
 		unsigned int *data, int size)
 {
 	struct usb_serial *serial = port->serial;
-	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
+	struct cp210x_serial_private *spriv = usb_get_serial_data(serial);
 	__le32 *buf;
 	int result, i, length;
 
@@ -345,13 +345,13 @@ static int cp210x_set_config(struct usb_serial_port *port, u8 request,
 		result = usb_control_msg(serial->dev,
 				usb_sndctrlpipe(serial->dev, 0),
 				request, REQTYPE_HOST_TO_INTERFACE, 0x0000,
-				port_priv->bInterfaceNumber, buf, size,
+				spriv->bInterfaceNumber, buf, size,
 				USB_CTRL_SET_TIMEOUT);
 	} else {
 		result = usb_control_msg(serial->dev,
 				usb_sndctrlpipe(serial->dev, 0),
 				request, REQTYPE_HOST_TO_INTERFACE, data[0],
-				port_priv->bInterfaceNumber, NULL, 0,
+				spriv->bInterfaceNumber, NULL, 0,
 				USB_CTRL_SET_TIMEOUT);
 	}
 
@@ -845,36 +845,30 @@ static void cp210x_break_ctl (struct tty_struct *tty, int break_state)
 
 static int cp210x_startup(struct usb_serial *serial)
 {
-	struct cp210x_port_private *port_priv;
-	int i;
+	struct usb_host_interface *cur_altsetting;
+	struct cp210x_serial_private *spriv;
 
 	/* cp210x buffers behave strangely unless device is reset */
 	usb_reset_device(serial->dev);
 
-	for (i = 0; i < serial->num_ports; i++) {
-		port_priv = kzalloc(sizeof(*port_priv), GFP_KERNEL);
-		if (!port_priv)
+	spriv = kzalloc(sizeof(*spriv), GFP_KERNEL);
+	if (!spriv)
 		return -ENOMEM;
 
-		port_priv->bInterfaceNumber =
-		    serial->interface->cur_altsetting->desc.bInterfaceNumber;
+	cur_altsetting = serial->interface->cur_altsetting;
+	spriv->bInterfaceNumber = cur_altsetting->desc.bInterfaceNumber;
 
-		usb_set_serial_port_data(serial->port[i], port_priv);
-	}
+	usb_set_serial_data(serial, spriv);
 
 	return 0;
 }
 
 static void cp210x_release(struct usb_serial *serial)
 {
-	struct cp210x_port_private *port_priv;
-	int i;
+	struct cp210x_serial_private *spriv;
 
-	for (i = 0; i < serial->num_ports; i++) {
-		port_priv = usb_get_serial_port_data(serial->port[i]);
-		kfree(port_priv);
-		usb_set_serial_port_data(serial->port[i], NULL);
-	}
+	spriv = usb_get_serial_data(serial);
+	kfree(spriv);
 }
 
 module_usb_serial_driver(serial_drivers, id_table);