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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>
This commit is contained in:
Julian Wiedmann 2018-03-21 17:14:00 +01:00 committed by Martin Schwidefsky
parent ab7efda477
commit 89286320a2
1 changed files with 3 additions and 1 deletions
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4
drivers/s390/cio/qdio_main.c
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@ -1207,8 +1207,10 @@ int qdio_shutdown(struct ccw_device *cdev, int how)
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);