[PATCH] usbserial: Regression in USB generic serial driver

Kernel version 2.6.13 introduced a regression in the generic USB
serial converter driver (usbserial.o, drivers/usb/serial/generic.c).
The bug manifests, as far as I can tell, whenever you attempt to write
to the device -- the write will never complete (write() returns 0, or
blocks).
Signed-off-by: NRandall Nortman <oss@wonderclown.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

drivers/usb/serial/generic.c

@@ -223,7 +223,7 @@ int usb_serial_generic_write_room (struct usb_serial_port *port)
 	dbg("%s - port %d", __FUNCTION__, port->number);
 
 	if (serial->num_bulk_out) {
-		if (port->write_urb_busy)
+		if (!(port->write_urb_busy))
 			room = port->bulk_out_size;
 	}