[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, 3 insertions, 1 deletions

diff --git a/drivers/s390/cio/device_status.c b/drivers/s390/cio/device_status.c
index 1b03c5423be2..5814dbee2410 100644
--- a/drivers/s390/cio/device_status.c
+++ b/drivers/s390/cio/device_status.c
@@ -56,7 +56,8 @@ ccw_device_path_notoper(struct ccw_device *cdev)
         struct subchannel *sch;
 
         sch = to_subchannel(cdev->dev.parent);
-        stsch (sch->schid, &sch->schib);
+        if (cio_update_schib(sch))
+                goto doverify;
 
         CIO_MSG_EVENT(0, "%s(0.%x.%04x) - path(s) %02x are "
                       "not operational \n", __func__,
@@ -64,6 +65,7 @@ ccw_device_path_notoper(struct ccw_device *cdev)
                       sch->schib.pmcw.pnom);
 
         sch->lpm &= ~sch->schib.pmcw.pnom;
+doverify:
         cdev->private->flags.doverify = 1;
 }