Re: TMF for a write with only unsolicited data

"Eddy Quicksall" <[email protected]> Tue, 14 Mar 2006 13:11:12 -0500

Newsgroups	gmane.ietf.ips
Message-ID	<[email protected]>

So the paragraph below is saying the WSA would be 0 if the Abort Task were aborting a Write that had only unsolicited data. That is the way I read it too. You further said that for this case there would be no DataDescriptorOut with the TMF call from the iSCSI layer to the iSER layer. I think that is now clear. Thanks.

WSV - Write STag Valid flag: 1 bit

This flag indicates the validity of the Write STag field of the
iSER Header. If set to one, the Write STag field in this iSER
Header is valid. If set to zero, the Write STag field in this
iSER Header MUST be ignored at the receiver. The Write STag
Valid flag is set to one when there is solicited data to be
transferred for a SCSI Write or bidirectional command, or when
there are non-immediate unsolicited and solicited data to be
transferred for the referenced task specified in a Task
Management Function Request with the TASK REASSIGN function.

----- Original Message -----
From: Mike Ko
To: Eddy Quicksall
Sent: Tuesday, March 14, 2006 12:58 PM
Subject: Re: [Ips] TMF for a write with only unsolicited data

Ergo, there is no DataDescriptorOut, and therefore no unsolicited data associated with the issuance of the Abort Task TMF.

Mike
To: "Mike Ko" <[email protected]>
cc:
Subject: Re: [Ips] TMF for a write with only unsolicited data

The TMF doesn't send any data. The TMF is aborting a task that has only unsolicited data.
----- Original Message -----
From: Mike Ko
To: Eddy Quicksall
Sent: Tuesday, March 14, 2006 12:25 PM
Subject: Re: [Ips] TMF for a write with only unsolicited data

Eddy,

AFAIK, other than Task Reassign, no TMF requires sending any data. The point of Abort Task is to kill that task and stop all work on the task, so sending data would be counter-productive.

Mike

To: "Mike Ko" <[email protected]>
cc:
Subject: Re: [Ips] TMF for a write with only unsolicited data

How about Abort Task?

Eddy
----- Original Message -----
From: Mike Ko
To: Eddy Quicksall
Cc: [email protected]
Sent: Tuesday, March 14, 2006 11:05 AM
Subject: Re: [Ips] TMF for a write with only unsolicited data

Eddy,

There are 8 task management function codes listed in RFC3720. They are Abort Task, Abort Task Set, Clear ACA, Clear Task Set, Logical Unit Reset, Target Warm Reset, Target Cold Reset, and Task Reassign. If your example is not Task Reassign, what TMF code do you have in mind where unsolicited write data would be sent?

Mike

To: "Mike Ko" <[email protected]>
cc: <[email protected]>
Subject: Re: [Ips] TMF for a write with only unsolicited data

No. The case is not a TASK REASSIGN. It is for a write command where all of the data is unsolicited.

If the STag is used for the associated R2T's then it would seem WSV would be set to 0 when no R2T's were issued.

Further it says "The Write STag
Valid flag is set to one when there is solicited data to be
transferred"

Doesn't that mean the STag is only used if there was solicited data with the command?

Eddy
----- Original Message -----
From: Mike Ko
To: Eddy Quicksall
Cc: [email protected]
Sent: Monday, March 13, 2006 7:14 PM
Subject: Re: [Ips] TMF for a write with only unsolicited data

If I understand your question correctly, I assume the TMF is a TASK REASSIGN and it is for a write command qualified with DataDescriptorOut. DataDescriptorOut is used to describe the I/O buffer starting with the immediate unsolicited data (if any), followed by the non-immediate unsolicited data (if any) and solicited data. A Write STag is allocated in this case. The Write STag is used by the iSER layer at the target in handling the data transfer associated with the R2T PDUs and in returning the SCSI Response PDU using the SendInvSE message. Since there is non-immediate unsolicited data, WSV is set to 1.

Mike

To: <[email protected]>
cc:
Subject: [Ips] TMF for a write with only unsolicited data

Suppose:
1) a TMF is not a TASK REASSIGN
2) the TMF is for a write command
3) the write command only has unsolicited data

I think this is saying the WSV is set to 0 for this case. Is that correct?

If so then I think the 3rd bullet item in 7.3.3 needs to say "if allocated" since a write with unsolicited only will also have a DataDescriptorOut.

Or am I wrong in that the TMF would have the DataDescriptorOut for a write with only unsolicited data?

WSV - Write STag Valid flag: 1 bit

7.3.3 Task Management Function Request/Response

* It MUST use the ITT as specified in the Referenced Task Tag from
the Task Management Function Request PDU to locate the existing
STag(s), if any, in the Local Mapping(s) that associates the ITT
to the local STag(s).

* It MUST invalidate the existing STag(s), if any, and the Local
Mapping(s) that associates the ITT to the local STag(s).

* It MUST allocate a Read STag for the I/O Buffer as defined by the
qualifier DataDescriptorIn if the Send_Control Operational
Primitive invocation is qualified with DataDescriptorIn.

Eddy_______________________________________________
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