[patch] s390: lost interrupt after chpid vary off/on cycle.

From: Martin Schwidefsky
Date: Mon Aug 07 2006 - 11:04:03 EST

From: Peter Oberparleiter <peter.oberparleiter@xxxxxxxxxx>

[S390] lost interrupt after chpid vary off/on cycle.

I/O on a CCW device may stall if a channel path to that device is
logicaly varied off/on. A user I/O interrupt can get misinterpreted
as interrupt for an internal path verification operation due to a
missing check and is therefore never reported to the device driver.

Correct check for pending interruptions before starting path

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>

drivers/s390/cio/device_fsm.c | 1 +
1 files changed, 1 insertion(+)

diff -urpN linux-2.6/drivers/s390/cio/device_fsm.c linux-2.6-patched/drivers/s390/cio/device_fsm.c
--- linux-2.6/drivers/s390/cio/device_fsm.c 2006-08-07 14:14:29.000000000 +0200
+++ linux-2.6-patched/drivers/s390/cio/device_fsm.c 2006-08-07 14:14:44.000000000 +0200
@@ -772,6 +772,7 @@ ccw_device_online_verify(struct ccw_devi
stsch(sch->schid, &sch->schib);

if (sch->schib.scsw.actl != 0 ||
+ (sch->schib.scsw.stctl & SCSW_STCTL_STATUS_PEND) ||
(cdev->private->irb.scsw.stctl & SCSW_STCTL_STATUS_PEND)) {
* No final status yet or final status not yet delivered
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