USB: fix usb_serial_suspend(): buggy code

Am Montag 23 Juli 2007 schrieb Adrian Bunk:
> Commit ec22559e added the following 
> function to drivers/usb/serial/usb-serial.c:
> 
[..]
> 
> The Coverity checker spotted the inconsequent NULL checking for "serial".
> 
> Looking at the code it also doesn't seem to have been intended to always 
> return 0.

Coverity is right. The check for NULL is wrongly done and the error
return is lost.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/serial/usb-serial.c

@@ -1077,16 +1077,17 @@ int usb_serial_suspend(struct usb_interface *intf, pm_message_t message)
 	struct usb_serial_port *port;
 	int i, r = 0;
 
-	if (serial) {
+	if (!serial) /* device has been disconnected */
+		return 0;
+
 	for (i = 0; i < serial->num_ports; ++i) {
 		port = serial->port[i];
 		if (port)
 			kill_traffic(port);
 	}
-	}
 
 	if (serial->type->suspend)
-		serial->type->suspend(serial, message);
+		r = serial->type->suspend(serial, message);
 
 	return r;
 }