s390/css: stop stsch loop after cc 3

Receiving cc=3 from store subchannel means 2 things:
* the subchannel is not provided
* there are no further subchannels in this subchannel set

With this patch we abort the store subchannel loop after cc=3 (or an
exception) and clear the subsequent bits in the subchannel id set.

Reported-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Acked-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index b4d572f..fd00afd 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -377,7 +377,11 @@
 		/* Will be done on the slow path. */
 		return -EAGAIN;
 	}
-	if (stsch_err(schid, &schib) || !css_sch_is_valid(&schib)) {
+	if (stsch_err(schid, &schib)) {
+		/* Subchannel is not provided. */
+		return -ENXIO;
+	}
+	if (!css_sch_is_valid(&schib)) {
 		/* Unusable - ignore. */
 		return 0;
 	}
@@ -536,6 +540,7 @@
 		case -ENOMEM:
 		case -EIO:
 			/* These should abort looping */
+			idset_sch_del_subseq(slow_subchannel_set, schid);
 			break;
 		default:
 			rc = 0;