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-rw-r--r--drivers/s390/cio/device_status.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/s390/cio/device_status.c b/drivers/s390/cio/device_status.c
index 6b1caea622ea..25d99bd28089 100644
--- a/drivers/s390/cio/device_status.c
+++ b/drivers/s390/cio/device_status.c
@@ -263,7 +263,11 @@ ccw_device_accumulate_irb(struct ccw_device *cdev, struct irb *irb)
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. */