提交 ba4ba8a6 编写于 作者: P Peter Oberparleiter 提交者: Martin Schwidefsky

[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: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
上级 64821324
......@@ -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. */
......
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