[PATCH] s390: dasd wait for clear i/o interrupt

The sleep_on function clears a running cqr without waiting for the related
interrupt.  This can lead to a panic at the time the interrupt is processed
because the related memory might already be freed.  Wait for clear-interrupt
and de-queue cqr prior to return.

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