1 files changed, 13 insertions, 1 deletions

diff --git a/drivers/s390/cio/device_status.c b/drivers/s390/cio/device_status.c
index 6b1caea622ea..aa96e6752592 100644
--- a/drivers/s390/cio/device_status.c
+++ b/drivers/s390/cio/device_status.c
@@ -221,6 +221,14 @@ ccw_device_accumulate_irb(struct ccw_device *cdev, struct irb *irb)
 
         cdev_irb = &cdev->private->irb;
 
+        /*
+         * If the clear function had been performed, all formerly pending
+         * status at the subchannel has been cleared and we must not pass
+         * intermediate accumulated status to the device driver.
+         */
+        if (irb->scsw.fctl & SCSW_FCTL_CLEAR_FUNC)
+                memset(&cdev->private->irb, 0, sizeof(struct irb));
+
         /* Copy bits which are valid only for the start function. */
         if (irb->scsw.fctl & SCSW_FCTL_START_FUNC) {
                 /* Copy key. */
@@ -263,7 +271,11 @@ 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. */