SAS (SPL) and ADT transport issues with TMF's

George Penokie george.penokie at avagotech.com
Wed Jul 2 06:21:24 PDT 2014


Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r1407020_f.htm">HTML-formatted message</a>

Kevin,
I see no real problem so I'm not sure what your point is. There are only
two TMFs that operate on an individual command (ABORT TASK and QUERY TASK).
Also, there is no queuing defined for the task router that is handling the
commands that do not have valid LUNs so those commands do not sit around.
They should to be processed immediately. By the time either of those TMFs
could be issued and handled the command should have ended.
Bye for now,
George Penokie
Avago Technologies
3033 41 St NW
Rochester , MN 55901
507-328-9017
george.penokie at avagotech.com
On Tue, Jul 1, 2014 at 6:42 PM, Kevin D Butt <kdbutt at us.ibm.com> wrote:
> My engineers have uncovered what we believe is a bug in the standards
> related to task management functions addressed to a logical unit that does
> not exist.
>
> In SPL-3 and ADT-2 the task management function IU's reject TMF's
> addressed to a logical unit that does not exist.  However, the SCSI command
> IU refers to SAM which says process REQUEST SENSE, REPORT LUNS, or INQUIRY
> and reject the rest.	These leaves a hole when a TMF needs to be performed
> on a REQUEST SENSE, REPORT LUNS, or INQUIRY with no way to do so.
>
> In SPL-3
> 8.2.2.1 COMMAND frame - Command information unit
> The LOGICAL UNIT NUMBER field specifies the logical unit number of the
> logical unit to which the task router shall route the command. The
> structure of the LOGICAL UNIT NUMBER field shall be as defined in SAM-5.
<<If
> the addressed logical unit does not exist, then the task router shall
> follow the rules for selection of incorrect logical units defined in
> SAM-5.>>
>
> 8.2.2.2 TASK frame - Task Management Function information unit
> The LOGICAL UNIT NUMBER field specifies the logical unit number of the
> logical unit, if any, to which the task router shall route the task
> management function. The structure of the LOGICAL UNIT NUMBER field shall
> be as defined in SAM-5. <<If the addressed logical unit does not exist,
> then the task router shall return a RESPONSE frame with the DATAPRES field
> set to RESPONSE_DATA and its RESPONSE CODE field set to INCORRECT LOGICAL
> UNIT NUMBER.>>
>
> In ADT-2
> 8.1.2 SCSI Command information unit
> The LUN field indicates the logical unit number to which the command
> shall be routed within the SCSI target device. <<If the addressed logical
> unit does not exist, the task manager shall follow the rules for selection
> of invalid logical units defined in SAM-4.>>
>
> 8.1.3 SCSI Task Management information unit
> The LOGICAL UNIT NUMBER field contains the address of the logical unit.
> The structure of the logical unit number field shall be as defined in
SAM-4.
> <<If the addressed logical unit does not exist, the task manager shall
> return a SCSI Response IU with its RESPONSE CODE field set to INVALID
> LOGICAL UNIT NUMBER IN SCSI TASK MANAGEMENT IU.>>
>
> SAM-5
> *5.11 Incorrect logical unit numbers for commands*
> The SCSI target device's processing of an incorrect logical unit number
> (see 4.7.1) is described in this subclause.
>
> In response to a REQUEST SENSE command, a REPORT LUNS command, or an
> INQUIRY command the SCSI target device shall respond as defined in SPC-4.
>
> Any command except REQUEST SENSE, REPORT LUNS, or INQUIRY:
> e) shall be terminated with CHECK CONDITION status, with the sense key set
> to ILLEGAL REQUEST, and with the additional sense code set to LOGICAL UNIT
> NOT SUPPORTED, if:
> A) the SCSI target device is not capable of supporting the logical unit
> (e.g., some SCSI target devices support only one peripheral device); or
> B) the SCSI target device supports the logical unit, but the peripheral
> device is not currently connected to the SCSI target device;
> or
> f) is responded to in a vendor specific manner, if:
> A) the SCSI target device supports the logical unit and the peripheral
> device is connected, but the peripheral device is not operational; or
> B) the SCSI target device supports the logical unit but is incapable of
> determining if the peripheral device is connected or is not operational
> because the peripheral device is not ready.
>
> Does anybody disagree?
>
> Kevin D. Butt
> SCSI Architect, Tape Firmware, T10 Standards
> Data Protection & Retention
> MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
> Tel: 520-799-5280
> Fax: 520-799-2723 (T/L:321)
> Email address: kdbutt at us.ibm.com
> http://www-03.ibm.com/servers/storage/



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