s390/cio: update measurement characteristics

BugLink: http://bugs.launchpad.net/bugs/1541534

Per channel path measurement characteristics are obtained during channel
path registration. However if some properties of a channel path change
we don't update the measurement characteristics.

Make sure to update the characteristics when we change the properties of
a channel path or receive a notification from FW about such a change.
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>
(cherry picked from commit 9f3d6d7a)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

drivers/s390/cio/chp.c

@@ -416,7 +416,8 @@ static void chp_release(struct device *dev)
  * chp_update_desc - update channel-path description
  * @chp - channel-path
  *
- * Update the channel-path description of the specified channel-path.
+ * Update the channel-path description of the specified channel-path
+ * including channel measurement related information.
  * Return zero on success, non-zero otherwise.
  */
 int chp_update_desc(struct channel_path *chp)
@@ -428,8 +429,10 @@ int chp_update_desc(struct channel_path *chp)
 		return rc;
 
 	rc = chsc_determine_fmt1_channel_path_desc(chp->chpid, &chp->desc_fmt1);
+	if (rc)
+		return rc;
 
-	return rc;
+	return chsc_get_channel_measurement_chars(chp);
 }
 
 /**
@@ -466,11 +469,6 @@ int chp_new(struct chp_id chpid)
 		ret = -ENODEV;
 		goto out_free;
 	}
-
-	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 */

drivers/s390/cio/chsc.c

@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/device.h>
+#include <linux/mutex.h>
 #include <linux/pci.h>
 
 #include <asm/cio.h>
@@ -224,8 +225,9 @@ static int s390_subchannel_remove_chpid(struct subchannel *sch, void *data)
 
 void chsc_chp_offline(struct chp_id chpid)
 {
-	char dbf_txt[15];
+	struct channel_path *chp = chpid_to_chp(chpid);
 	struct chp_link link;
+	char dbf_txt[15];
 
 	sprintf(dbf_txt, "chpr%x.%02x", chpid.cssid, chpid.id);
 	CIO_TRACE_EVENT(2, dbf_txt);
@@ -236,6 +238,11 @@ void chsc_chp_offline(struct chp_id chpid)
 	link.chpid = chpid;
 	/* Wait until previous actions have settled. */
 	css_wait_for_slow_path();
+
+	mutex_lock(&chp->lock);
+	chp_update_desc(chp);
+	mutex_unlock(&chp->lock);
+
 	for_each_subchannel_staged(s390_subchannel_remove_chpid, NULL, &link);
 }
 
@@ -690,8 +697,9 @@ static void chsc_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 
 void chsc_chp_online(struct chp_id chpid)
 {
-	char dbf_txt[15];
+	struct channel_path *chp = chpid_to_chp(chpid);
 	struct chp_link link;
+	char dbf_txt[15];
 
 	sprintf(dbf_txt, "cadd%x.%02x", chpid.cssid, chpid.id);
 	CIO_TRACE_EVENT(2, dbf_txt);
@@ -701,6 +709,11 @@ void chsc_chp_online(struct chp_id chpid)
 		link.chpid = chpid;
 		/* Wait until previous actions have settled. */
 		css_wait_for_slow_path();
+
+		mutex_lock(&chp->lock);
+		chp_update_desc(chp);
+		mutex_unlock(&chp->lock);
+
 		for_each_subchannel_staged(__s390_process_res_acc, NULL,
 					   &link);
 		css_schedule_reprobe();