Re: Question On R2T Behaviour?

["Anshul Chadda" <achadda@trebia.com>]

Hi Suresh:
I believe that the target can take step 1. But then the problem might still
prevail. Why?? If the initiator wasn't able to send Data for the first R2T,
there is no guarantee that it will be able to send the same data (that it
couldn't send before) for the second R2T. So, the target cannot try sending
R2T asking for the same data infinitely.

I don't think it is an error if the initiator is not able to send the whole
data, involved in an R2T, as long as it sets the F bit to 1 in the final
Data-Out PDU (mentioned in Step 2).

I would assume that the target has an option to take care of this behavior
by sending SCSI Response PDU with U-bit set and the Residual Count set to a
data value that it was not able to receive.This step can be taken by the
target as a conservative one and can serve as a fallback solution in case
step 1 doesn't work.

Anshul

> 1. It looks intutive that target may send another R2T with different
>    sequence number and collect the data initially that the host
>    was not able to send for the previous R2T request.
>

> Or
>
> 2. It is an error that need to be detected by target that the host was not
>    able to fully satisfy the R2T request sent by the target in the first
> place.
>