Patch "s390/dasd: prevent prefix I/O error" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

s390/dasd: prevent prefix I/O error

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
s390-dasd-prevent-prefix-i-o-error.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Stefan Haberland <[email protected]>
Date: Thu, 26 Oct 2017 14:37:35 +0200
Subject: s390/dasd: prevent prefix I/O error

From: Stefan Haberland <[email protected]>

[ Upstream commit da340f921d3454f1521671c7a5a43ad3331fbe50 ]

Prevent that a prefix flag is set based on invalid configuration data. The validity.verify_base flag should only be set for alias devices. Usually the unit address type is either one of base, PAV alias or HyperPAV alias. But in cases where the unit address type is not set or any other value the validity.verify_base flag might be set as well. This would lead to follow on errors.
Explicitly check for alias devices and set the validity flag only for them.

---
 drivers/s390/block/dasd_eckd.c |   16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

@@ -530,10 +530,12 @@ static int prefix_LRE(struct ccw1 *ccw,
 	pfxdata->validity.define_extent = 1;
 
 	/* private uid is kept up to date, conf_data may be outdated */
-	if (startpriv->uid.type != UA_BASE_DEVICE) {
+	if (startpriv->uid.type == UA_BASE_PAV_ALIAS)
 		pfxdata->validity.verify_base = 1;
-		if (startpriv->uid.type == UA_HYPER_PAV_ALIAS)
-			pfxdata->validity.hyper_pav = 1;
+
+	if (startpriv->uid.type == UA_HYPER_PAV_ALIAS) {
+		pfxdata->validity.verify_base = 1;
+		pfxdata->validity.hyper_pav = 1;
 	}
 
 	rc = define_extent(NULL, dedata, trk, totrk, cmd, basedev, blksize);

@@ -3414,10 +3416,12 @@ static int prepare_itcw(struct itcw *itc
 	pfxdata.validity.define_extent = 1;
 
 	/* private uid is kept up to date, conf_data may be outdated */
-	if (startpriv->uid.type != UA_BASE_DEVICE) {
+	if (startpriv->uid.type == UA_BASE_PAV_ALIAS)
+		pfxdata.validity.verify_base = 1;
+
+	if (startpriv->uid.type == UA_HYPER_PAV_ALIAS) {
 		pfxdata.validity.verify_base = 1;
-		if (startpriv->uid.type == UA_HYPER_PAV_ALIAS)
-			pfxdata.validity.hyper_pav = 1;
+		pfxdata.validity.hyper_pav = 1;
 	}
 
 	switch (cmd) {

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/s390-dasd-prevent-prefix-i-o-error.patch