[PATCH] s390: 64 bit diag250 support

Add support for diag 250 access to dasd devices for 64 bit kernels.  In
addition fix detach/attach for diag disks.  The VM control block needs to get
recreated by a call to mdsk_init_io.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/s390/block/Kconfig

@@ -49,7 +49,7 @@ config DASD_FBA
 
 config DASD_DIAG
 	tristate "Support for DIAG access to Disks"
-	depends on DASD && ARCH_S390X = 'n'
+	depends on DASD && ( ARCH_S390X = 'n' || EXPERIMENTAL)
 	help
 	  Select this option if you want to use Diagnose250 command to access
 	  Disks under VM.  If you are not running under VM or unsure what it is,