Subject: [Ips] iSCSI: abort task set

From: "Eddy Quicksall" <[email-masked]>
Date: Wed, 28 Jan 2004 16:39:29 -0500

I've always wondered about the following paragraph but never asked.

10.6.2 says:
The target:

a) Receives the ABORT TASK SET/CLEAR TASK SET request.

b) Waits for all target transfer tags to be responded to

and for all affected tasks in the task set to be

received.

How can the target determine that all affected tasks in the task set have been received? Does this simply mean that the target must sequence the TMF just as any other command even if the TMF is immediate?

What about if TST is 000b? How do I determine when some other initiator has sent all affected tasks?

Eddy

---

From: [email-masked]
Date: Fri, 30 Jan 2004 10:16:57 -0800 (PST)

On Wed, 28 Jan 2004, Eddy Quicksall wrote:

> How can the target determine that all affected tasks in the task set
> have been received? Does this simply mean that the target must sequence
> the TMF just as any other command even if the TMF is immediate?

I don't think so. I think the best way to think of it is that at some
point, the TMF starts being processed. You abort all tasks active at that
point.

I think it's mostly saying that the target waits for all outstanding TTTs
to be answered. All tasks stop generating new target tasks; writes stop
generating new R2Ts and reads stop generating bursts. The initiator
terminates all outstanding tasks by sending data and setting the 'F' bit.
It also answers any outstanding Data In runs (where the 'A' bit was set).

i.e. it's doing the gentle shutdown the iSCSI spec describes, on all of
the tasks.

I guess you'd also start a timer on the task(s), and if they weren't
completed in a timely manner then you just kill them. Like if an initiator
aborting the task set to clean up after an initiator that has gone off
line.

> has sent all affected tasks?

Pick a moment in time (grab a lock somewhere). Everything that exists at
that moment gets killed. Everything else doesn't.

Note that this applies to tasks in the task set, which as I understand it
is a SCSI thing. I think your comments about waiting have to do with
commands in the CmdSN queue. Since they aren't in the SCSI task set yet, I
don't think you have to worry about them. At least I don't. :-)

Take care,

Bill

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