s390/qdio: clear intparm during shutdown

During shutdown, qdio returns its ccw device back to control by the
upper-layer driver. But there is a remote chance that by the time where the
IRQ handler gets switched back, the interrupt for the preceding
ccw_device_{clear,halt} hasn't been presented yet.
Upper-layer drivers would then need to handle this IRQ - and since the IO
is issued with an intparm, it could very well be confused with whatever
intparm mechanism the driver uses itself (eg intparm == request address).

So when switching over the IRQ handler, also clear the intparm and have
upper-layer drivers deal with any such delayed interrupt as if it was
unsolicited.

Suggested-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index a337281337a71ef9f7a4589036ff62b654c465c2..f4ca72dd862ff37db969271e56c0ecbbb095a199 100644 (file)
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -1207,8 +1207,10 @@ no_cleanup:
        qdio_shutdown_thinint(irq_ptr);
 
        /* restore interrupt handler */
-       if ((void *)cdev->handler == (void *)qdio_int_handler)
+       if ((void *)cdev->handler == (void *)qdio_int_handler) {
                cdev->handler = irq_ptr->orig_handler;
+               cdev->private->intparm = 0;
+       }
        spin_unlock_irq(get_ccwdev_lock(cdev));
 
        qdio_set_state(irq_ptr, QDIO_IRQ_STATE_INACTIVE);