[PATCH] s390: dasd driver.

[PATCH] s390: dasd driver.

From: Martin Schwidefsky <schwidefsky@de.ibm.com>

dasd device driver changes:
 - After a state change interrupt restart all running i/o on queue
   and reset device timer.
 - Improve some debug messages.
 - Lower timeout of reserve/release/steal_lock to 2 seconds.
 - Fix BIODASDPSRD ioctl.
 - Replace ro_flag, use_diag_flag and disconnect_error_flag words by bits.
 - Use BLKPG_DEL_PARTITION ioctl instead of a call to delete_partition because
   delete_partition is not an exported function. Since dasd_destroy_partitions
   can't do blkdev_get because dasd_open would fail, keep the block device
   open as long as partitions exist. This in turn requires a different
   approach to the open vs. offline race.