[Stgt-devel] [PATCH] iscsi fix xmit param

[Pete Wyckoff]

tomof at acm.org wrote on Wed, 15 Aug 2007 12:11 +0900:
> On Tue, 14 Aug 2007 17:52:06 -0500
> Pete Wyckoff <pw at osc.edu> wrote:
> 
> > This might be a hack.  In fixing the defaults earlier, I put the
> > SCSI default for MaxRecvDataSegmentLength in place for the
> > ISCSI_PARAM_MAX_XMIT_DLENGTH.  But really it should be whatever
> > the initiator tells us.
> 
> Not sure. Initiators can declarer whatever about MRDSL, the target can
> use a lower value than it. And the target administrator should be able
> to configure it.
> 
> That's the current behaivoir (taken from IET).

True.  There are a few cases.

1.  ini sends mrdsl > target mxdsl.  Apply minimum, use target max.
2.  ini sends mrdsl < target mxdsl.  Apply minimum, use ini max.
3.  ini does not mention mrdsl.  Target should set its mxdsl to the
    standard default (8192), not use its default max.

This last case was broken before my earlier patch "iscsi param
cleanup".  Now it is fixed but I changed the target default to 8k.
I want the target to agree to use a larger value if the initiator is
willing, but still get case #3 correct if the initiator does not
specify.

Here's a better patch.  Tested with all cases of ini <,>,= target,
and target 8k or 256k mxdsl.

		-- Pete

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