On 01/29/2013 12:32 PM, Heiko Carstens wrote:
On Tue, Jan 29, 2013 at 08:11:56AM +0100, Hannes Reinecke wrote:
This patch implements generic block layer timeout handling
callbacks for DASDs. When the timeout expires the respective
cqr is aborted.
With this timeout handler time-critical request abort
is guaranteed as the abort does not depend on the internal
state of the various DASD driver queues.
Signed-off-by: Hannes Reinecke <h...@suse.de>
Acked-by: Stefan Weinhuber <w...@de.ibm.com>
[...]
+enum blk_eh_timer_return dasd_times_out(struct request *req)
+{
+ struct dasd_ccw_req *cqr = req->completion_data;
+ struct dasd_block *block = req->q->queuedata;
+ struct dasd_device *device;
+ int rc = 0;
+
+ if (!cqr)
+ return BLK_EH_NOT_HANDLED;
+
+ device = cqr->startdev ? cqr->startdev : block->base;
+ DBF_DEV_EVENT(DBF_WARNING, device,
+ " dasd_times_out cqr %p status %x",
+ cqr, cqr->status);
+
+ spin_lock(&block->queue_lock);
+ spin_lock(get_ccwdev_lock(device->cdev));
^^^
+ cqr->retries = -1;
+ cqr->intrc = -ETIMEDOUT;
+ if (cqr->status >= DASD_CQR_QUEUED) {
+ spin_unlock(get_ccwdev_lock(device->cdev));
+ 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;
+
+ list_for_each_entry_safe(searchcqr, nextcqr,
+ &block->ccw_queue, blocklist) {
+ tmpcqr = searchcqr;
+ while (tmpcqr->refers)
+ tmpcqr = tmpcqr->refers;
+ if (tmpcqr != cqr)
+ continue;
+ /* searchcqr is an ERP request for cqr */
+ searchcqr->retries = -1;
+ searchcqr->intrc = -ETIMEDOUT;
+ if (searchcqr->status >= DASD_CQR_QUEUED) {
+ spin_lock(get_ccwdev_lock(device->cdev));
^^^
This looks like a potential dead lock.
Right.
Will be resending the patch.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
h...@suse.de +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
