4.14-stable review patch. If anyone has any objections, please let me know.
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From: Stefan Haberland sth@linux.vnet.ibm.com
[ Upstream commit 9487cfd3430d07366801886bdf185799a2b6f066 ]
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 Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/s390/block/dasd.c | 21 +++++++-------------- 1 file changed, 7 insertions(+), 14 deletions(-)
--- a/drivers/s390/block/dasd.c +++ b/drivers/s390/block/dasd.c @@ -2596,8 +2596,6 @@ int dasd_cancel_req(struct dasd_ccw_req 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 */ @@ -3917,9 +3915,12 @@ static int dasd_generic_requeue_all_requ 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); @@ -3932,13 +3933,6 @@ static int dasd_generic_requeue_all_requ 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( @@ -3955,8 +3949,7 @@ static int dasd_generic_requeue_all_requ 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; }