[S390] cio: introduce cio_update_schib

There is the chance that we get condition code 0 for a stsch but
the resulting schib is not vaild. In the current code there are
2 cases:
* we do a check for validity of the schib after stsch, but at this
  time we have already stored the invaild schib in the subchannel
  structure. This may lead to problems.
* we don't do a check for validity, which is not that good either.

The patch addresses both issues by introducing the stsch wrapper
cio_update_schib which performs stsch on a local schib. This schib
is only written back to the subchannel if it's valid.

side note: For some functions (chp_events) the return codes are
different now (-ENXIO vs -ENODEV) but this shouldn't do harm
since the caller doesn't check for _specific_ errors.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 17 insertions, 11 deletions

diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c
index 01330cf5ae5e..e1a3786779ba 100644
--- a/drivers/s390/cio/device_fsm.c
+++ b/drivers/s390/cio/device_fsm.c
@@ -140,8 +140,7 @@ ccw_device_cancel_halt_clear(struct ccw_device *cdev)
 	int ret;
 
 	sch = to_subchannel(cdev->dev.parent);
-	ret = stsch(sch->schid, &sch->schib);
-	if (ret || !sch->schib.pmcw.dnv)
+	if (cio_update_schib(sch))
 		return -ENODEV; 
 	if (!sch->schib.pmcw.ena)
 		/* Not operational -> done. */
@@ -245,11 +244,13 @@ ccw_device_recog_done(struct ccw_device *cdev, int state)
 	 * through ssch() and the path information is up to date.
 	 */
 	old_lpm = sch->lpm;
-	stsch(sch->schid, &sch->schib);
-	sch->lpm = sch->schib.pmcw.pam & sch->opm;
+
 	/* Check since device may again have become not operational. */
-	if (!sch->schib.pmcw.dnv)
+	if (cio_update_schib(sch))
 		state = DEV_STATE_NOT_OPER;
+	else
+		sch->lpm = sch->schib.pmcw.pam & sch->opm;
+
 	if (cdev->private->state == DEV_STATE_DISCONNECTED_SENSE_ID)
 		/* Force reprobe on all chpids. */
 		old_lpm = 0;
@@ -549,7 +550,11 @@ ccw_device_verify_done(struct ccw_device *cdev, int err)
 
 	sch = to_subchannel(cdev->dev.parent);
 	/* Update schib - pom may have changed. */
-	stsch(sch->schid, &sch->schib);
+	if (cio_update_schib(sch)) {
+		cdev->private->flags.donotify = 0;
+		ccw_device_done(cdev, DEV_STATE_NOT_OPER);
+		return;
+	}
 	/* Update lpm with verified path mask. */
 	sch->lpm = sch->vpm;
 	/* Repeat path verification? */
@@ -667,7 +672,7 @@ ccw_device_offline(struct ccw_device *cdev)
 		return 0;
 	}
 	sch = to_subchannel(cdev->dev.parent);
-	if (stsch(sch->schid, &sch->schib) || !sch->schib.pmcw.dnv)
+	if (cio_update_schib(sch))
 		return -ENODEV;
 	if (scsw_actl(&sch->schib.scsw) != 0)
 		return -EBUSY;
@@ -745,7 +750,10 @@ ccw_device_online_verify(struct ccw_device *cdev, enum dev_event dev_event)
 	 * Since we might not just be coming from an interrupt from the
 	 * subchannel we have to update the schib.
 	 */
-	stsch(sch->schid, &sch->schib);
+	if (cio_update_schib(sch)) {
+		ccw_device_verify_done(cdev, -ENODEV);
+		return;
+	}
 
 	if (scsw_actl(&sch->schib.scsw) != 0 ||
 	    (scsw_stctl(&sch->schib.scsw) & SCSW_STCTL_STATUS_PEND) ||
@@ -1011,9 +1019,7 @@ void ccw_device_trigger_reprobe(struct ccw_device *cdev)
 
 	sch = to_subchannel(cdev->dev.parent);
 	/* Update some values. */
-	if (stsch(sch->schid, &sch->schib))
-		return;
-	if (!sch->schib.pmcw.dnv)
+	if (cio_update_schib(sch))
 		return;
 	/*
 	 * The pim, pam, pom values may not be accurate, but they are the best