s390/qdio: clear intparm during shutdown

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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>

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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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drivers/s390/cio/qdio_main.c

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