From: Hans-Joachim Picht <hpicht@redhat.com>
Date: Tue, 30 Oct 2007 17:04:18 +0100
Subject: [s390] cio: handle invalid subchannel setid in stsch
Message-id: 20071030160418.GE6604@redhat.com
O-Subject: [RHEL5.2 PATCH 5/5] s390 cio: Handle invalid subchannel set id in stsch
Bugzilla: 354831

Problem:
=========

When the common I/O layer is forced to rescan on all possible
subchannels on a machine check, it looks at all subchannel ids
created by for_each_subchannel().
Those subchannel ids may contain an invalid subchannel set id, which will
cause an operand exception on stsch.
Using stsch_err which can handle this operand exceptions.

Bugzilla
=========

BZ 354831
https://bugzilla.redhat.com/show_bug.cgi?id=354831

Upstream status of the patch:
=============================
Fix is in git, commit 758976f9a55cb22ddc602a0690d67f9546e3e43f

Test status:
============
Kernel with patch was built and successfully tested

Please ACK.

With best regards,

Hans

diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
index 1310dbf..1554416 100644
--- a/drivers/s390/cio/chsc.c
+++ b/drivers/s390/cio/chsc.c
@@ -618,7 +618,7 @@ __chp_add_new_sch(struct subchannel_id schid)
 	struct schib schib;
 	int ret;
 
-	if (stsch(schid, &schib))
+	if (stsch_err(schid, &schib))
 		/* We're through */
 		return need_rescan ? -EAGAIN : -ENXIO;
 
diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index ca0a31d..e822faa 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -294,7 +294,7 @@ static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 		/* Will be done on the slow path. */
 		return -EAGAIN;
 	}
-	if (stsch(schid, &schib) || !schib.pmcw.dnv) {
+	if (stsch_err(schid, &schib) || !schib.pmcw.dnv) {
 		/* Unusable - ignore. */
 		return 0;
 	}