s390/dasd: fix hanging device after clear subchannel

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>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 65894f0..a0630eb 100644 (file)
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -1593,9 +1593,18 @@ void dasd_int_handler(struct ccw_device *cdev, unsigned long intparm,
        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: "
@@ -1611,7 +1620,6 @@ void dasd_int_handler(struct ccw_device *cdev, unsigned long intparm,
        }
 
        now = get_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) &&