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

[FUJITA Tomonori]

From: Pete Wyckoff <pw at osc.edu>
Subject: Re: [Stgt-devel] [PATCH] iscsi fix xmit param
Date: Wed, 15 Aug 2007 11:15:59 -0500

> 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.

Really?

I think that if ini does not mention mrdsl and target doesn't use the
standard default mxdsl value (a target admin sets non default value),
text_check_param() sets xmdsl to the default value.