[PATCH] s390: block device driver

[PATCH] s390: block device driver

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

block device driver changes:
 - dasd: Fix diag discipline if it is loaded as a module.
 - dcssblk: Replace r/w lock with r/w semaphore to be able to call
   device_register inside a critical section.
 - dcssblk: Fix error handling in write function for dcss "add" attribute.
 - xpram & dcssblk: Fix sanity check for sector number.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>