[NTDEV]Driver design issues for 2000; DMA zero length transfers .- ..

This is a rehash of an old question, but the response meter never raised
above 0 when I asked it the last time. Since it is rather important in the
scheme of my design, I thought maybe rephrasing would help.

I have a need to do a zero length transfer when using
DmaOperations->GetScatterGatherList. Thus far, the methods I have used have
resulted in rejections, most often by Driver Verifier.

The logic I am using, uses the buffer coming from a Read/WriteFile as a
control block that contains several pieces of information that must be
passed to my HBA. My HBA is a fibrechannel device, the QLogic 2100/2200
specifically. The driver I am writing will allow an application to function
as a target, thus the need to do zero length data or payload transfers. As
an example, a Test Unit Ready response from the Target is contained solely
in the CDB, which is passed as “side band” information, and is not part of
the payload. My current solution is to use GetScatterGatherList for non-zero
length transfers and AllocateAdapterChannel for side band only transfers,
but that is a complexity I would like to avoid.

Does anyone know of a proper way to do zero length transfers using
GetScatterGatherList, or does this come under the category of “It don’t work
that way”?

Gary


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