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Commit 159a7ff7 authored by Gwendal Grignou's avatar Gwendal Grignou Committed by Jeff Garzik
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sata_mv: Prevent PIO commands to be defered too long if traffic in progress. 



Use excl_link when non NCQ commands are defered, to be sure they are processed
as soon as outstanding commands are completed. It prevents some commands to be
defered indifinitely when using a port multiplier.

Signed-off-by: default avatarGwendal Grignou <gwendal@google.com>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
parent 6d4f950e

drivers/ata/sata_mv.c

+27 −2
Original line number Diff line number Diff line
@@ -1382,6 +1382,25 @@ static int mv_qc_defer(struct ata_queued_cmd *qc) 
	 */

	if (pp->pp_flags & MV_PP_FLAG_DELAYED_EH)

		return ATA_DEFER_PORT;



	/* PIO commands need exclusive link: no other commands [DMA or PIO]

	 * can run concurrently.

	 * set excl_link when we want to send a PIO command in DMA mode

	 * or a non-NCQ command in NCQ mode.

	 * When we receive a command from that link, and there are no

	 * outstanding commands, mark a flag to clear excl_link and let

	 * the command go through.

	 */

	if (unlikely(ap->excl_link)) {

		if (link == ap->excl_link) {

			if (ap->nr_active_links)

				return ATA_DEFER_PORT;

			qc->flags |= ATA_QCFLAG_CLEAR_EXCL;

			return 0;

		} else

			return ATA_DEFER_PORT;

	}



	/*

	 * If the port is completely idle, then allow the new qc.

	 */
@@ -1395,8 +1414,14 @@ static int mv_qc_defer(struct ata_queued_cmd *qc) 
	 * doesn't allow it.

	 */

	if ((pp->pp_flags & MV_PP_FLAG_EDMA_EN) &&

	    (pp->pp_flags & MV_PP_FLAG_NCQ_EN) && ata_is_ncq(qc->tf.protocol))

	    (pp->pp_flags & MV_PP_FLAG_NCQ_EN)) {

		if (ata_is_ncq(qc->tf.protocol))

			return 0;

		else {

			ap->excl_link = link;

			return ATA_DEFER_PORT;

		}

	}



	return ATA_DEFER_PORT;

}