ide: dequeue in-flight request
ide generally has single request in flight and tracks it using
hwif->rq and all state handlers follow the following convention.
* ide_started is returned if the request is in flight.
* ide_stopped is returned if the queue needs to be restarted. The
request might or might not have been processed fully or partially.
* hwif->rq is set to NULL, when an issued request completes.
So, dequeueing model can be implemented by dequeueing after fetch,
requeueing if hwif->rq isn't NULL on ide_stopped return and doing
about the same thing on completion / port unlock paths. These changes
can be made in ide-io proper.
In addition to the above main changes, the following updates are
necessary.
* ide-cd shouldn't dequeue a request when issuing REQUEST SENSE for it
as the request is already dequeued.
* ide-atapi uses request queue as stack when issuing REQUEST SENSE to
put the REQUEST SENSE in front of the failed request. This now
needs to be done using requeueing.
[ Impact: dequeue in-flight request ]
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/ide/ide-atapi.c b/drivers/ide/ide-atapi.c
index 792534d..2874c3d 100644
--- a/drivers/ide/ide-atapi.c
+++ b/drivers/ide/ide-atapi.c
@@ -246,6 +246,7 @@
*/
void ide_retry_pc(ide_drive_t *drive)
{
+ struct request *failed_rq = drive->hwif->rq;
struct request *sense_rq = &drive->sense_rq;
struct ide_atapi_pc *pc = &drive->request_sense_pc;
@@ -260,8 +261,17 @@
if (drive->media == ide_tape)
set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
- if (ide_queue_sense_rq(drive, pc))
- ide_complete_rq(drive, -EIO, blk_rq_bytes(drive->hwif->rq));
+ /*
+ * Push back the failed request and put request sense on top
+ * of it. The failed command will be retried after sense data
+ * is acquired.
+ */
+ blk_requeue_request(failed_rq->q, failed_rq);
+ drive->hwif->rq = NULL;
+ if (ide_queue_sense_rq(drive, pc)) {
+ blkdev_dequeue_request(failed_rq);
+ ide_complete_rq(drive, -EIO, blk_rq_bytes(failed_rq));
+ }
}
EXPORT_SYMBOL_GPL(ide_retry_pc);