[S390] cio: Device status validity.
Only accumulate device status field in irb if it is valid.
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
diff --git a/drivers/s390/cio/device_status.c b/drivers/s390/cio/device_status.c
index 6b1caea..25d99bd 100644
--- a/drivers/s390/cio/device_status.c
+++ b/drivers/s390/cio/device_status.c
@@ -263,7 +263,11 @@
cdev_irb->scsw.cpa = irb->scsw.cpa;
/* Accumulate device status, but not the device busy flag. */
cdev_irb->scsw.dstat &= ~DEV_STAT_BUSY;
- cdev_irb->scsw.dstat |= irb->scsw.dstat;
+ /* dstat is not always valid. */
+ if (irb->scsw.stctl &
+ (SCSW_STCTL_PRIM_STATUS | SCSW_STCTL_SEC_STATUS
+ | SCSW_STCTL_INTER_STATUS | SCSW_STCTL_ALERT_STATUS))
+ cdev_irb->scsw.dstat |= irb->scsw.dstat;
/* Accumulate subchannel status. */
cdev_irb->scsw.cstat |= irb->scsw.cstat;
/* Copy residual count if it is valid. */