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s390/dasd: fix handling of internal requests

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Internal DASD device driver I/O such as query host access count or
path verification is started using the _sleep_on() function.
To mark a request as started or ended the callback_data is set to either
DASD_SLEEPON_START_TAG or DASD_SLEEPON_END_TAG.

In cases where the request has to be stopped unconditionally the status is
set to DASD_SLEEPON_END_TAG as well which leads to immediate clearing of
the request.
But the request might still be on a device request queue for normal
operation which might lead to a panic because of a BUG() statement in
__dasd_device_process_final_queue() or a list corruption of the device
request queue.

Fix by removing the setting of DASD_SLEEPON_END_TAG in the
dasd_cancel_req() and dasd_generic_requeue_all_requests() functions and
ensure that the request is not deleted in the requeue function.
Trigger the device tasklet in the requeue function and let the normal
processing cleanup the request.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Stefan Haberland 2018-02-07 17:39:14 +01:00 committed by Martin Schwidefsky
parent 91ab883eb2
commit 9487cfd343
1 changed files with 7 additions and 14 deletions
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21
drivers/s390/block/dasd.c
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@ -2581,8 +2581,6 @@ int dasd_cancel_req(struct dasd_ccw_req *cqr)
case DASD_CQR_QUEUED:
/* request was not started - just set to cleared */
cqr->status = DASD_CQR_CLEARED;
if (cqr->callback_data == DASD_SLEEPON_START_TAG)
cqr->callback_data = DASD_SLEEPON_END_TAG;
break;
case DASD_CQR_IN_IO:
/* request in IO - terminate IO and release again */
@ -3902,9 +3900,12 @@ static int dasd_generic_requeue_all_requests(struct dasd_device *device)
wait_event(dasd_flush_wq,
(cqr->status != DASD_CQR_CLEAR_PENDING));
/* mark sleepon requests as ended */
if (cqr->callback_data == DASD_SLEEPON_START_TAG)
cqr->callback_data = DASD_SLEEPON_END_TAG;
/*
* requeue requests to blocklayer will only work
* for block device requests
*/
if (_dasd_requeue_request(cqr))
continue;
/* remove requests from device and block queue */
list_del_init(&cqr->devlist);
@ -3917,13 +3918,6 @@ static int dasd_generic_requeue_all_requests(struct dasd_device *device)
cqr = refers;
}
/*
* requeue requests to blocklayer will only work
* for block device requests
*/
if (_dasd_requeue_request(cqr))
continue;
if (cqr->block)
list_del_init(&cqr->blocklist);
cqr->block->base->discipline->free_cp(
@ -3940,8 +3934,7 @@ static int dasd_generic_requeue_all_requests(struct dasd_device *device)
list_splice_tail(&requeue_queue, &device->ccw_queue);
spin_unlock_irq(get_ccwdev_lock(device->cdev));
}
/* wake up generic waitqueue for eventually ended sleepon requests */
wake_up(&generic_waitq);
dasd_schedule_device_bh(device);
return rc;
}