On Thu, Aug 14, 2014 at 04:30:58PM +0300, Dolev Raviv wrote:
> From: Subhash Jadavani <subha...@codeaurora.org>
>
> REPORT LUNS command has "SELECT REPORT" field which controls what type of
> logical units to be reported by device server. According to UFS device
> standard, if this field is set to 0, REPORT LUNS would report only report
> standard logical units. If it's set to 1 then it would report only well
> known logical unit and if it's set to 2 then device would report both
> standard and well known logical units.
> Some well-known logical units might not have scsi upper-layer drivers. In
> such cases, the runtime PM reference count increased during device
> enumeration will not be decreased, causing the parent device (host) to
> always be on even during idle.
>
> This change allows the SCSI LLD (Low Level Driver) to choose which type
> of logical units should be detected.
>
> Signed-off-by: Subhash Jadavani <subha...@codeaurora.org>
> Signed-off-by: Sujit Reddy Thumma <sthu...@codeaurora.org>
> Signed-off-by: Dolev Raviv <dra...@codeaurora.org>
>
> diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
> index 4a6e4ba..5a0e164 100644
> --- a/drivers/scsi/scsi_scan.c
> +++ b/drivers/scsi/scsi_scan.c
> @@ -802,6 +802,14 @@ static int scsi_add_lun(struct scsi_device *sdev,
> unsigned char *inq_result,
> } else {
> sdev->type = (inq_result[0] & 0x1f);
> sdev->removable = (inq_result[1] & 0x80) >> 7;
> +
> + /*
> + * some devices may respond with wrong type for
> + * well-known logical units. Force well-known type
> + * to enumerate them correctly.
> + */
> + if (scsi_is_wlun(sdev->lun) && (sdev->type != TYPE_WLUN))
> + sdev->type = TYPE_WLUN;
no need to test for TYPE_WLUN here.
> switch (sdev->type) {
> @@ -817,6 +825,7 @@ static int scsi_add_lun(struct scsi_device *sdev,
> unsigned char *inq_result,
> case TYPE_COMM:
> case TYPE_RAID:
> case TYPE_OSD:
> + case TYPE_WLUN:
> sdev->writeable = 1;
> break;
> case TYPE_ROM:
This switch statements has been removed in 3.17-rc1, please rebase your
series on top of it. While you're at it please make this patch, which
introduceѕ core scsi changes first in the series.
> @@ -1412,6 +1421,13 @@ static int scsi_report_lun_scan(struct scsi_target
> *starget, int bflags,
> */
> memset(&scsi_cmd[1], 0, 5);
>
> + if (shost->report_wlus)
> + /*
> + * Set "SELECT REPORT" field to 0x2 which will make device to
> + * report well known logical units along with standard LUs.
> + */
> + scsi_cmd[2] = 0x2;
So we're finally getting well known LUN support. I think we should key this
off the SBC compliance level and not have the drivers opt in.
> diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
> index 5f36788..ba9d0f0 100644
> --- a/drivers/scsi/scsi_sysfs.c
> +++ b/drivers/scsi/scsi_sysfs.c
> @@ -1060,6 +1060,13 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
> }
> }
>
> + /*
> + * put runtime pm reference for well-known logical units,
> + * drivers are expected to _get_* again during probe.
> + */
> + if (scsi_is_wlun(sdev->lun))
> + scsi_autopm_put_device(sdev);
Special casing the well known LUNs here seems wrong. Shouldn't we do this
for any devices that don't get a driver attached to them?
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