Re: mpt(4) timeout recovery improvements

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

So, to partially answer myself:

> scsipi/driver interaction (is there documentation on this?)
I had missed the comprehensive scsipi(9) man page. I guess I mis-typed
"scsipi" when looking for it.

> First question: what's the appropriate xs->error?
So this has been answered both by me finding that man page and by Brian.

> Second question: When repeatedly calling scsipi_done(), can it happen that 
> scsipi tries to re-queue these requests before I return? I would then loose 
> them when re-initializing the IOC.
From the man page, I guess this can be prevented by scsipi_channel_freeze()?

> Third question: Do I need to care about xs->xs_callout?
This has also been answerd by bot Brian and me finding the man page.
I didn't realize that mpt(4) did itself set up that callout.

> Or is returning everything to scsipi simply the wrong approach?
Given there is XS_REQUEUE, I now think it's the right approach. But I may 
be wrong, of course.