[PATCH 4.4 058/192] [PATCH 060/135] s390/cio: ensure consistent measurement state

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 61f0bfcf8020f02eb09adaef96745d1c1d1b3623 ]

Make sure that in all cases where we could not obtain measurement
characteristics the associated fields are set to invalid values.

Note: without this change the "shared" capability of a channel path
for which we could not obtain the measurement characteristics was
incorrectly displayed as 0 (not shared). We will now correctly
report "unknown" in this case.

Signed-off-by: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Peter Oberparleiter <oberpar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/s390/cio/chp.c  |   13 +++++--------
 drivers/s390/cio/chsc.c |   12 ++++++++----
 2 files changed, 13 insertions(+), 12 deletions(-)

--- a/drivers/s390/cio/chp.c
+++ b/drivers/s390/cio/chp.c
@@ -466,14 +466,11 @@ int chp_new(struct chp_id chpid)
 		ret = -ENODEV;
 		goto out_free;
 	}
-	/* Get channel-measurement characteristics. */
-	if (css_chsc_characteristics.scmc && css_chsc_characteristics.secm) {
-		ret = chsc_get_channel_measurement_chars(chp);
-		if (ret)
-			goto out_free;
-	} else {
-		chp->cmg = -1;
-	}
+
+	ret = chsc_get_channel_measurement_chars(chp);
+	if (ret)
+		goto out_free;
+
 	dev_set_name(&chp->dev, "chp%x.%02x", chpid.cssid, chpid.id);
 
 	/* make it known to the system */
--- a/drivers/s390/cio/chsc.c
+++ b/drivers/s390/cio/chsc.c
@@ -1003,6 +1003,12 @@ int chsc_get_channel_measurement_chars(s
 		u32 data[NR_MEASUREMENT_CHARS];
 	} __attribute__ ((packed)) *scmc_area;
 
+	chp->shared = -1;
+	chp->cmg = -1;
+
+	if (!css_chsc_characteristics.scmc || !css_chsc_characteristics.secm)
+		return 0;
+
 	spin_lock_irq(&chsc_page_lock);
 	memset(chsc_page, 0, PAGE_SIZE);
 	scmc_area = chsc_page;
@@ -1023,11 +1029,9 @@ int chsc_get_channel_measurement_chars(s
 			      scmc_area->response.code);
 		goto out;
 	}
-	if (scmc_area->not_valid) {
-		chp->cmg = -1;
-		chp->shared = -1;
+	if (scmc_area->not_valid)
 		goto out;
-	}
+
 	chp->cmg = scmc_area->cmg;
 	chp->shared = scmc_area->shared;
 	if (chp->cmg != 2 && chp->cmg != 3) {