per-command component that we *don't* try and pass thru CAM. CAM just
is too risky and too much of a pain- structures get copied, but not
all info of interest can be considered safely transported thru all
consumers (including user space) from the incoming ATIO to the outgoing
CTIO- it's just much safer to have a buddy structure, identified by the
command's tag which *does* make it thru safely.
Pay attention to link speed and report 200MB/s xfer speed for a
23XX card in 2GPs mode.
MFC after: 1 week
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