using the ahc driver hang when probing scsi devices. The problem may be in
the ahc driver and not in this change, but back it out until this has been
fixed anyway.
called via a callout, kick the completion thread to run it for us (uses
a new flag, SCSIPI_CHAN_KICK).
If we've received BUSY status and we haven't started the completion
thread yet, don't freeze do a callout to scsipi_periph_timed_thaw which
then will try and kick the completion thread- instead treat the command
as if it were a polled command and just call delay for 1 second.
If DIAGNOSTIC is defined, and the periph qfreeze count is less than
zero, panic because some HBA has corrupted the periph structure's
accounting.
not present" don't print any message but still return ENODEV.
Use this in cd driver to allow open of character raw partition even if
the drive is empty (older drives fails at LOAD_UNLOAD time, newer
ones fail at TEST_UNIT_READY time).
some devices can't handle tag number larger than some values and always
reject commands with QUEUE FULL if the tag number is larger than this.
Under some circonstances the scsipi system may not decrease periph_openings
(as a workaround of other odd behavior) and we may end up requeuing the command
with a hight tag value again, and the driver could loop on this.
Workaround: in case of queue full, decrease periph_openings to
min(periph_active - 1, periph_openings - 1) so that, after some iteration,
periph_openings is less than the max tag value acceptable by the device.
Solves the problem with tagged queuing on ncr53c9x for me.
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
to remove all xfers from the pending queue. It removes only xfers for
asynchronous transactions. So, simply loop over all pending xfers
with calling scsipi_done and wait xfers to drain. Addresses PR#9703.
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.
- `flags' is now gone, replaced with `xs_control' and `xs_status'.
- Massive cleanup of the control flags. Now we explicitly say that
a job is to complete asynchronously, rather than relying on side-effects,
and use a new flag to now that device discovery is being performed.
- Do SCSI device discovery interrupt-driven.
in the drive. restrict "opening of empty drive" to character devices only
(reading a block device returns a short read instead of ENODEV, which can lead
to confusion).
fredette