On Mon, Oct 12, 2009 at 3:44 PM, Gwendal Grignou <gwendal@xxxxxxxxxx> wrote:
> 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: Gwendal Grignou <gwendal@xxxxxxxxxx>
Reviewed-by: Grant Grundler <grundler@xxxxxxxxxx>
thanks,
grant
> ---
> drivers/ata/sata_mv.c | 29 +++++++++++++++++++++++++++--
> 1 files changed, 27 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
> index 17f9ff9..6f5093b 100644
> --- a/drivers/ata/sata_mv.c
> +++ b/drivers/ata/sata_mv.c
> @@ -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))
> - return 0;
> + (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;
> }
> --
> 1.5.4.3
>
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