block->request_queue is used many times in dasd_setup_queue. Define a
separate variable to increase readability a bit and to make it better
reusable.
Reviewed-by: NStefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: NJan Höppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>