s390/dasd: fix handling of internal requests (9487cfd3) · Commits · 戴 / test

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>

drivers/s390/block/dasd.c

+7 −14

Original line number	Diff line number	Diff line
		@@ -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;
		}

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