[PATCH] pl2303 - unplug device.

It's possible to unplug usb device and do tiocmset() and tiocmget() without
valid interface in pl2303 module.

The patch below check this and return -ENODEV if interface was removed.

From: Flavio Leitner <fbl@conectiva.com.br>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff -purN linux-05-04-11/drivers/usb/serial/pl2303.c linux-05-04-11.usb/drivers/usb/serial/pl2303.c

drivers/usb/serial/pl2303.c

@@ -677,6 +677,9 @@ static int pl2303_tiocmset (struct usb_serial_port *port, struct file *file,
 	unsigned long flags;
 	u8 control;
 
+	if (!usb_get_intfdata(port->serial->interface))
+		return -ENODEV;
+
 	spin_lock_irqsave (&priv->lock, flags);
 	if (set & TIOCM_RTS)
 		priv->line_control |= CONTROL_RTS;
@@ -702,6 +705,9 @@ static int pl2303_tiocmget (struct usb_serial_port *port, struct file *file)
 
 	dbg("%s (%d)", __FUNCTION__, port->number);
 
+	if (!usb_get_intfdata(port->serial->interface))
+		return -ENODEV;
+
 	spin_lock_irqsave (&priv->lock, flags);
 	mcr = priv->line_control;
 	status = priv->line_status;