[S390] cio: Make isc handling more robust.

Introduce an ->isc field in the subchannel to store the desired
interruption subclass, since sch->schib.pmcw.isc may be overwritten
by the hardware on stsch() after machine checks.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/cio.h b/drivers/s390/cio/cio.h
index 08f2235..3c75412 100644
--- a/drivers/s390/cio/cio.h
+++ b/drivers/s390/cio/cio.h
@@ -74,6 +74,7 @@
 	__u8 lpm;		/* logical path mask */
 	__u8 opm;               /* operational path mask */
 	struct schib schib;	/* subchannel information block */
+	int isc; /* desired interruption subclass */
 	struct chsc_ssd_info ssd_info;	/* subchannel description */
 	struct device dev;	/* entry in device tree */
 	struct css_driver *driver;
@@ -85,7 +86,7 @@
 #define to_subchannel(n) container_of(n, struct subchannel, dev)
 
 extern int cio_validate_subchannel (struct subchannel *, struct subchannel_id);
-extern int cio_enable_subchannel(struct subchannel *, unsigned int, u32);
+extern int cio_enable_subchannel(struct subchannel *, u32);
 extern int cio_disable_subchannel (struct subchannel *);
 extern int cio_cancel (struct subchannel *);
 extern int cio_clear (struct subchannel *);