From: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Date: Thu, 27 Jul 2006 12:00:23 +0000 (+0200)
Subject: [S390] permanent subchannel busy conditions may cause I/O stall
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=ba4ba8a69dcb446450b5ddeca48a7bd15783f4c2;p=linux.git

[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>
---

diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c
index ac6e0c7e43d95..7a39e0b0386c6 100644
--- a/drivers/s390/cio/device_fsm.c
+++ b/drivers/s390/cio/device_fsm.c
@@ -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. */