[PATCH 3.14 20/35] s390/dasd: fix hanging device after clear subchannel

Greg Kroah-Hartman
2016-09-05T17:44:43Z

From: Stefan Haberland <sth@linux.vnet.ibm.com>

commit 9ba333dc55cbb9523553df973adb3024d223e905 upstream.

When a device is in a status where CIO has killed all I/O by itself the
interrupt for a clear request may not contain an irb to determine the
clear function. Instead it contains an error pointer -EIO.
This was ignored by the DASD int_handler leading to a hanging device
waiting for a clear interrupt.

Handle -EIO error pointer correctly for requests that are clear pending and
treat the clear as successful.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Reviewed-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/s390/block/dasd.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -1613,9 +1613,18 @@ void dasd_int_handler(struct ccw_device
unsigned long long now;
int expires;

+ cqr = (struct dasd_ccw_req *) intparm;
if (IS_ERR(irb)) {
switch (PTR_ERR(irb)) {
case -EIO:
+ if (cqr && cqr->status == DASD_CQR_CLEAR_PENDING) {
+ device = (struct dasd_device *) cqr->startdev;
+ cqr->status = DASD_CQR_CLEARED;
+ dasd_device_clear_timer(device);
+ wake_up(&dasd_flush_wq);
+ dasd_schedule_device_bh(device);
+ return;
+ }
break;
case -ETIMEDOUT:
DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s: "
@@ -1631,7 +1640,6 @@ void dasd_int_handler(struct ccw_device
}

now = get_tod_clock();
- cqr = (struct dasd_ccw_req *) intparm;
/* check for conditions that should be handled immediately */
if (!cqr ||
!(scsw_dstat(&irb->scsw) == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&