On Tue, May 19, 2009 at 12:52:45AM -0500, michaelc@xxxxxxxxxxx wrote:
> From: Mike Christie <michaelc@xxxxxxxxxxx>
>
> This has scsi-ml call the change_queue_depth functions when
> we get a QUEUE_FULL. It will only change the queue depth if
> change_queue_depth is set because the LLD may have to
> modify some internal resources, so I thought this would
> be the safest route.
>
>
> Signed-off-by: Mike Christie <michaelc@xxxxxxxxxxx>
> ---
> drivers/scsi/scsi_error.c | 26 +++++++++++++++++++++++++-
> 1 files changed, 25 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
> index 0c2c73b..792644e 100644
> --- a/drivers/scsi/scsi_error.c
> +++ b/drivers/scsi/scsi_error.c
> @@ -331,6 +331,27 @@ static int scsi_check_sense(struct scsi_cmnd *scmd)
> }
> }
>
> +static void scsi_handle_queue_full(struct scsi_device *sdev)
> +{
> + struct scsi_host_template *sht = sdev->host->hostt;
> + struct scsi_device *tmp_sdev;
> +
> + if (!sht->change_queue_depth)
> + return;
> +
> + shost_for_each_device(tmp_sdev, sdev->host) {
> + if (tmp_sdev->id != sdev->id)
> + continue;
> + /*
> + * We do not know the number of commands that were at
> + * the device when we got the queue full so we start
> + * from the highest possible value and work our way down.
> + */
> + sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth - 1,
> + SCSI_QDEPTH_QFULL);
> + }
> +}
> +
This was called because of a "queue full" for one SCSI device. Why do
you decrement the queue depth for all SCSI devices on the same host
and not only for one device?
I think the overall approach looks good.
Thanks for working on this,
Christof
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