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Commit 1bcdb535 authored by Sebastian Ott's avatar Sebastian Ott Committed by Martin Schwidefsky
Browse files

s390/dasd: simplify locking in dasd_times_out 



Provide __dasd_cancel_req that is called with the ccw device lock
held to simplify the locking in dasd_times_out. Also this removes
the following sparse warning:
context imbalance in 'dasd_times_out' - different lock contexts for basic block

Note: with this change dasd_schedule_device_bh is now called (via
dasd_cancel_req) with the ccw device lock held. But is is already
the case for other codepaths.

Signed-off-by: default avatarSebastian Ott <sebott@linux.ibm.com>
Reviewed-by: default avatarStefan Haberland <sth@linux.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent a166c368

drivers/s390/block/dasd.c

+17 −14
Original line number Diff line number Diff line
@@ -2569,14 +2569,11 @@ EXPORT_SYMBOL(dasd_sleep_on_immediatly); 
 * Cancellation of a request is an asynchronous operation! The calling

 * function has to wait until the request is properly returned via callback.

 */

int dasd_cancel_req(struct dasd_ccw_req *cqr)

static int __dasd_cancel_req(struct dasd_ccw_req *cqr)

{

	struct dasd_device *device = cqr->startdev;

	unsigned long flags;

	int rc;

	int rc = 0;



	rc = 0;

	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);

	switch (cqr->status) {

	case DASD_CQR_QUEUED:

		/* request was not started - just set to cleared */
@@ -2596,11 +2593,21 @@ int dasd_cancel_req(struct dasd_ccw_req *cqr) 
	default: /* already finished or clear pending - do nothing */

		break;

	}

	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);

	dasd_schedule_device_bh(device);

	return rc;

}

EXPORT_SYMBOL(dasd_cancel_req);



int dasd_cancel_req(struct dasd_ccw_req *cqr)

{

	struct dasd_device *device = cqr->startdev;

	unsigned long flags;

	int rc;



	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);

	rc = __dasd_cancel_req(cqr);

	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);

	return rc;

}



/*

 * SECTION: Operations of the dasd_block layer.
@@ -3082,12 +3089,10 @@ enum blk_eh_timer_return dasd_times_out(struct request *req, bool reserved) 
	cqr->retries = -1;

	cqr->intrc = -ETIMEDOUT;

	if (cqr->status >= DASD_CQR_QUEUED) {

		spin_unlock(get_ccwdev_lock(device->cdev));

		rc = dasd_cancel_req(cqr);

		rc = __dasd_cancel_req(cqr);

	} else if (cqr->status == DASD_CQR_FILLED ||

		   cqr->status == DASD_CQR_NEED_ERP) {

		cqr->status = DASD_CQR_TERMINATED;

		spin_unlock(get_ccwdev_lock(device->cdev));

	} else if (cqr->status == DASD_CQR_IN_ERP) {

		struct dasd_ccw_req *searchcqr, *nextcqr, *tmpcqr;
@@ -3102,9 +3107,7 @@ enum blk_eh_timer_return dasd_times_out(struct request *req, bool reserved) 
			searchcqr->retries = -1;

			searchcqr->intrc = -ETIMEDOUT;

			if (searchcqr->status >= DASD_CQR_QUEUED) {

				spin_unlock(get_ccwdev_lock(device->cdev));

				rc = dasd_cancel_req(searchcqr);

				spin_lock(get_ccwdev_lock(device->cdev));

				rc = __dasd_cancel_req(searchcqr);

			} else if ((searchcqr->status == DASD_CQR_FILLED) ||

				   (searchcqr->status == DASD_CQR_NEED_ERP)) {

				searchcqr->status = DASD_CQR_TERMINATED;
@@ -3118,8 +3121,8 @@ enum blk_eh_timer_return dasd_times_out(struct request *req, bool reserved) 
			}

			break;

		}

		spin_unlock(get_ccwdev_lock(device->cdev));

	}

	spin_unlock(get_ccwdev_lock(device->cdev));

	dasd_schedule_block_bh(block);

	spin_unlock(&block->queue_lock);

	spin_unlock_irqrestore(&cqr->dq->lock, flags);