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[S390] permanent subchannel busy conditions may cause I/O stall 

In special conditions where a subchannel rejects the HALT I/O-
instruction with a busy indication (cc 2), I/O may stall.
I/O request termination logic retries HALT I/O indefinitely
because it expects HALT I/O to alter the subchannel status which
is not true when cc 2 is returned.
In case of a busy indication, try CLEAR I/O instruction immediately.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Peter Oberparleiter 2006-07-27 14:00:23 +02:00 committed by Martin Schwidefsky
parent 64821324ca
commit ba4ba8a69d
1 changed files with 2 additions and 1 deletions
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3
drivers/s390/cio/device_fsm.c
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@ -152,7 +152,8 @@ ccw_device_cancel_halt_clear(struct ccw_device *cdev)
if (cdev->private->iretry) {
cdev->private->iretry--;
ret = cio_halt(sch);
return (ret == 0) ? -EBUSY : ret;
if (ret != -EBUSY)
return (ret == 0) ? -EBUSY : ret;
}
/* halt io unsuccessful. */
cdev->private->iretry = 255; /* 255 clear retries. */