[S390] New DASD feature for ERP related logging

It is now possible to enable/disable ERP related logging without re-compile
and re-ipl. A additional sysfs-attribute 'erplog' allows to switch the
logging non-interruptive.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 2af2d9b..492b68b 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -1050,10 +1050,10 @@
 		}
 	} else {		/* error */
 		memcpy(&cqr->irb, irb, sizeof (struct irb));
-#ifdef ERP_DEBUG
-		/* dump sense data */
-		dasd_log_sense(cqr, irb);
-#endif
+		if (device->features & DASD_FEATURE_ERPLOG) {
+			/* dump sense data */
+			dasd_log_sense(cqr, irb);
+		}
 		switch (era) {
 		case dasd_era_fatal:
 			cqr->status = DASD_CQR_FAILED;