This is a completely rewritten scsipi_xfer execution engine, and the
associated changes to HBA drivers. Overview of changes & features:
- All xfers are queued in the mid-layer, rather than doing so in an
ad-hoc fashion in individual adapter drivers.
- Adapter/channel resource management in the mid-layer, avoids even trying
to start running an xfer if the adapter/channel doesn't have the resources.
- Better communication between the mid-layer and the adapters.
- Asynchronous event notification mechanism from adapter to mid-layer and
peripherals.
- Better peripheral queue management: freeze/thaw, sorted requeueing during
recovery, etc.
- Clean separation of peripherals, adapters, and adapter channels (no more
scsipi_link).
- Kernel thread for each scsipi_channel makes error recovery much easier
(no more dealing with interrupt context when recovering from an error).
- Mid-layer support for tagged queueing: commands can have the tag type
set explicitly, tag IDs are allocated in the mid-layer (thus eliminating
the need to use buggy tag ID allocation schemes in many adapter drivers).
- support for QUEUE FULL and CHECK CONDITION status in mid-layer; the command
will be requeued, or a REQUEST SENSE will be sent as appropriate.
Just before the merge syssrc has been tagged with thorpej_scsipi_beforemerge
there are some pathological cases that cause pmap_page_protect()
to be called on a wired page to revoke all mappings. We
need to skip mappings that are actually wired to prevent Bad
things from happening later.
THIS IS JUST A WORK-AROUND. We need to prevent the pathological
behavior from happening in UVM to begin with. But it's unclear
what the right solution is there, right now.
array of those structures at the end of the pmap structure. We compute
the size of the pmap structure based on the maximum CPU ID for a
particular machine. This gives us better cache behavior and better
memory footprint for the ASN info.
Three different IRQ:s can be selected for each event, 9, 11, or 13
(which selects hardware priority). More events to be added as they
are discovered. Do not use shb_intr_establish() to register IRQ 9, 11
or 13 anymore.
- pmap_enter()
- pmap_remove()
- pmap_protect()
- pmap_kenter_pa()
- pmap_kremove()
as described in pmap(9).
These calls are relatively conservative. It may be possible to
optimize these a little more.
tsubai