Re: iSCSI: immediate data

[sandeepj@research.bell-labs.com (Sandeep Joshi)]

Umm.....Julian replied to this one and said the final bit on ScsiCmd 
would indicate it.   Apparently, a single command can now send 
the unsolicited data both with the command and in separate PDUs.

I cant seem to find the email but I believe Sec 2.3.1 was changed 
accordingly.  Julian..?

-Sandeep

> The intention is that if an initiator requests to send immediate data (and is
> granted the request), then it will always send immediate data.
> 
> It sounds like you are asking for wishy washy mode... sometimes send immediate
> data, sometimes not.
> 
> -Matt
> 
> Sandeep Joshi wrote:
> > 
> > Julian,
> > 
> > I had a follow-up question on an old thread.
> >   http://ips.pdl.cs.cmu.edu/mail/msg03373.html
> > 
> > The initiator is allowed to send firstburst in immediate
> > or in separate PDUs...but can it do neither ?  I dont
> > see any statement to the effect that it MUST send a
> > firstburst.
> > 
> > Here's a possible problem :
> > 1) FirstBurst is 4K
> > 2) Expected data length of command is 16K
> > 3) Initiator sends the Scsi command without immediate
> >    data.   (final flag on Scsi command is not set)
> >    And it decides to send no further data PDUs.
> > 
> > The target does not know if R2Ts can be sent since it does
> > not know if any unsolicited PDUs are expected.
> > 
> > Perhaps the semantics on the final flag on SCSI command
> > need to be changed to indicate that no unsolicited data
> > will be sent with this command.  Currently, the flag implies
> > (Sec 2.3.1) that all the required data has been sent with
> > the command.
> > 
> > And here's a typo to fix.  Appendix E (Key=immediateData)
> > The following should say "initialR2T is no".
> > The table has got it right.
> > 
> > > If ImmediateData is set to yes and InitialR2T is set
> > > to yes then the initiator MAY send unsolicited immediate
> > > data or one unsolicited burst of Data-OUT PDUs but
> > > MUST NOT send both immediate and a unsolicited burst of
> > > Data-OUT PDUs for any one command.
> > 
> > -Sandeep