s390/cio: ensure consistent measurement state

[ Upstream commit 61f0bfcf ]

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@linux.vnet.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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;
-	}
+
 	dev_set_name(&chp->dev, "chp%x.%02x", chpid.cssid, chpid.id);
 
 	/* make it known to the system */

drivers/s390/cio/chsc.c

@@ -1003,6 +1003,12 @@ int chsc_get_channel_measurement_chars(struct channel_path *chp)
 		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(struct channel_path *chp)
 			      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) {