everything "scsi_*", since we really are talking about the SCSI command
set, ATAPI transport not withstanding. Improve the names of many structures,
and prepend "SCSI_" onto all SCSI command opcodes. Place items described
by the SCSI Primary Commands document into scsi_spc.h.
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
timeout()/untimeout() API:
- Clients supply callout handle storage, thus eliminating problems of
resource allocation.
- Insertion and removal of callouts is constant time, important as
this facility is used quite a lot in the kernel.
The old timeout()/untimeout() API has been removed from the kernel.
struct scsipi_adapter; they were not used.
Add a scsipi_ioctl entry point to struct scsipi_adapter. This will be
used to issue ioctl commands to the host adapters.
Inspired by PR #6090, from Matt Jacob.
Cute buglet: you can end up with zero CCBs if there were no targets
seen by the adapter. Always leave a minimum so the adapter can
finish attaching- it may be there w/o targets for a reason.
more robust in resource shortage situations, basically identical to
code I added to the "ahc" driver some time ago.
Thanks to Brad Spencer for the testing help.
should creation/initialization of a ccb fail. Also, don't panic in
these situations. Instead, simply return an error condition and allow
the caller to deal with it. It may be the case that we were able to
create one ccb what we can grab, and continue to hobble along.
martin