Commit 8f6205cd authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

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: default avatarTejun 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: default avatarJens Axboe <jens.axboe@oracle.com>
parent 1011c1b9

drivers/ide/ide-atapi.c

+12 −2
Original line number Diff line number Diff line
@@ -246,6 +246,7 @@ EXPORT_SYMBOL_GPL(ide_queue_sense_rq); 
 */

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 @@ void ide_retry_pc(ide_drive_t *drive) 
	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);

drivers/ide/ide-cd.c

+0 −8
Original line number Diff line number Diff line
@@ -405,15 +405,7 @@ static int cdrom_decode_status(ide_drive_t *drive, u8 stat) 


end_request:

	if (stat & ATA_ERR) {

		struct request_queue *q = drive->queue;

		unsigned long flags;



		spin_lock_irqsave(q->queue_lock, flags);

		blkdev_dequeue_request(rq);

		spin_unlock_irqrestore(q->queue_lock, flags);



		hwif->rq = NULL;



		return ide_queue_sense_rq(drive, rq) ? 2 : 1;

	} else

		return 2;

drivers/ide/ide-io.c

+27 −7
Original line number Diff line number Diff line
@@ -487,10 +487,10 @@ void do_ide_request(struct request_queue *q) 


	if (!ide_lock_port(hwif)) {

		ide_hwif_t *prev_port;



		WARN_ON_ONCE(hwif->rq);

repeat:

		prev_port = hwif->host->cur_port;

		hwif->rq = NULL;



		if (drive->dev_flags & IDE_DFLAG_SLEEPING &&

		    time_after(drive->sleep, jiffies)) {

			ide_unlock_port(hwif);
@@ -519,7 +519,12 @@ repeat: 
		 * we know that the queue isn't empty, but this can happen

		 * if the q->prep_rq_fn() decides to kill a request

		 */

		if (!rq) {

			rq = elv_next_request(drive->queue);

			if (rq)

				blkdev_dequeue_request(rq);

		}



		spin_unlock_irq(q->queue_lock);

		spin_lock_irq(&hwif->lock);
@@ -555,8 +560,11 @@ repeat: 
		startstop = start_request(drive, rq);

		spin_lock_irq(&hwif->lock);



		if (startstop == ide_stopped)

		if (startstop == ide_stopped) {

			rq = hwif->rq;

			hwif->rq = NULL;

			goto repeat;

		}

	} else

		goto plug_device;

out:
@@ -572,18 +580,24 @@ plug_device: 
plug_device_2:

	spin_lock_irq(q->queue_lock);



	if (rq)

		blk_requeue_request(q, rq);

	if (!elv_queue_empty(q))

		blk_plug_device(q);

}



static void ide_plug_device(ide_drive_t *drive)

static void ide_requeue_and_plug(ide_drive_t *drive, struct request *rq)

{

	struct request_queue *q = drive->queue;

	unsigned long flags;



	spin_lock_irqsave(q->queue_lock, flags);



	if (rq)

		blk_requeue_request(q, rq);

	if (!elv_queue_empty(q))

		blk_plug_device(q);



	spin_unlock_irqrestore(q->queue_lock, flags);

}
@@ -632,6 +646,7 @@ void ide_timer_expiry (unsigned long data) 
	unsigned long	flags;

	int		wait = -1;

	int		plug_device = 0;

	struct request	*uninitialized_var(rq_in_flight);



	spin_lock_irqsave(&hwif->lock, flags);
@@ -693,6 +708,8 @@ void ide_timer_expiry (unsigned long data) 
		spin_lock_irq(&hwif->lock);

		enable_irq(hwif->irq);

		if (startstop == ide_stopped) {

			rq_in_flight = hwif->rq;

			hwif->rq = NULL;

			ide_unlock_port(hwif);

			plug_device = 1;

		}
@@ -701,7 +718,7 @@ void ide_timer_expiry (unsigned long data) 


	if (plug_device) {

		ide_unlock_host(hwif->host);

		ide_plug_device(drive);

		ide_requeue_and_plug(drive, rq_in_flight);

	}

}
@@ -787,6 +804,7 @@ irqreturn_t ide_intr (int irq, void *dev_id) 
	ide_startstop_t startstop;

	irqreturn_t irq_ret = IRQ_NONE;

	int plug_device = 0;

	struct request *uninitialized_var(rq_in_flight);



	if (host->host_flags & IDE_HFLAG_SERIALIZE) {

		if (hwif != host->cur_port)
@@ -866,6 +884,8 @@ irqreturn_t ide_intr (int irq, void *dev_id) 
	 */

	if (startstop == ide_stopped) {

		BUG_ON(hwif->handler);

		rq_in_flight = hwif->rq;

		hwif->rq = NULL;

		ide_unlock_port(hwif);

		plug_device = 1;

	}
@@ -875,7 +895,7 @@ out: 
out_early:

	if (plug_device) {

		ide_unlock_host(hwif->host);

		ide_plug_device(drive);

		ide_requeue_and_plug(drive, rq_in_flight);

	}



	return irq_ret;

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