[S390] cio: Fix handling of interrupt for csch().

Wipe internal irb if the clear function bit is set before accumulating
bits from the irb in order to follow hardware behaviour.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/s390/cio/device_status.c b/drivers/s390/cio/device_status.c
index 25d99bd28089..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. */