This patch converts over hpsa to use the pci_alloc_irq_vectors including
the PCI_IRQ_AFFINITY flag that automatically assigns spread out irq
affinity to the I/O queues.

It also cleans up the per-ctrl interrupt state due to the use of the
pci_irq_vector and pci_free_irq_vectors helpers that don't need to know
the exact irq type.  Additionally it changes a little oddity in the
existing code that was using different array indixes into the per-vector
arrays depending on whether a controller is using a single INTx or
single MSI irq.

[mkp: fixed typo]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NDon Brace <don.brace@microsemi.com>
Tested-by: NDon Brace <don.brace@microsemi.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

calling fill_cmd() using a MACRO definition not handled in switch
statement causes BUG() to be called.
Signed-off-by: NDon Brace <don.brace@microsemi.com>
Reviewed-by: NScott Teel <scott.teel@microsemi.com>
Reviewed-by: NKevin Barnett <kevin.barnett@microsemi.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Need to report HBA device removal faster than the
event handler polling interval.

Stop I/O to the removed disk and wait for all
I/O operations to flush before removing the device.
Reviewed-by: NScott Teel <scott.teel@microsemi.com>
Reviewed-by: NKevin Barnett <kevin.barnett@microsemi.com>
Signed-off-by: NDon Brace <don.brace@microsemi.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Reviewed-by: NJustin Lindley <justin.lindley@microsemi.com>
Reviewed-by: NKevin Barnett <kevin.barnett@microsemi.com>
Reviewed-by: NMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: NDon Brace <don.brace@microsemi.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

SAS transport places devices on bus 0 but driver was setting the bus to
3.
Reviewed-by: NJustin Lindley <justin.lindley@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NJustin Lindley <justin.lindley@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

There are problems with getting configuration change notification
in pass-through RAID environments.  So, activate flag
h->discovery_polling when one of these devices is detected in
update_scsi_devices.

After discovery_polling is set, execute a report luns from
rescan_controller_worker (every 30 seconds).

If the data from report_luns is different than last
time (binary compare), execute a full rescan via update_scsi_devices.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NJustin Lindley <justin.lindley@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

External array LUNs must use target and lun numbers assigned by the
external array. So the driver must treat these differently from
local LUNs when assigning lun/target.

LUN's 'model' field has been used to detect Lun types that need
special treatment, but the desire is to eliminate the need to reference
specific array models, and support any external array.

Pass-through RAID (PTRAID) luns are not luns of the local controller,
so they are not reported in LUN count of command 'ID controller'.
However, they ARE reported in "Report logical Luns" command.
Local luns are listed first, then PTRAID LUNs.

The number of luns from "Report LUNs" in excess of those reported by
'ID controller' are therefore the PTRAID LUNS.

We can now remove function is_ext_target, and the 'white list'
array of supported model names.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NJustin Lindley <justin.lindley@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Reviewed-by: NMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

setup for sas transport. Need to set the
bus and target accordingly.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NJustin Lindley <justin.lindley@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Reviewed-by: NMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

remove repeated calculation that checks for physical
or logical devices.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NJustin Lindley <justin.lindley@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

remove macros and cleanup device exposure checking
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NJustin Lindley <justin.lindley@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Set reset type in device_reset_handler to do either
logical unit reset for logical devices, or physical
target reset, for physical devices.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NJustin Lindley <justin.lindley@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Fix a NULL pointer issue in the driver when devices are removed
during a reset.
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NJustin Lindley <justin.lindley@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by; Hannes Reinecke <hare@suse.de>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

This member is used in calls to scsi_device_type.
It should be unsigned since the kernel checks for upper bounds
and it should never be negative.
Suggested-by: NTomas Henzl <thenzl@redhat.com>
Suggested-by: NHannes Reinecke <hare@suse.de>
Suggested-by: NMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

host no, bus, target, lun, scsi_device_type
for hba mode add: box and bay information

report if the path is active/inactive
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

need to add PMC to copyright notice and update the Hewlett-Packard
copyright notification.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NJustin Lindley <justin.lindley@pmcs.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Synchronize completion the reset with completion of outstanding commands

Extending the newly-added synchronous abort functionality,
now also synchronize resets with the completion of outstanding commands.
Rename the wait queue to reflect the fact that it's being used for both
types of waits.  Also, don't complete commands which are terminated
due to a reset operation.

fix for controller lockup during reset
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NHannes Reinecke <hare@Suse.de>
Signed-off-by: NWebb Scales <webbnh@hp.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Rework slave allocation:
  - separate the tagging support setup from the hostdata setup
  - make the hostdata setup act consistently when the lookup fails
  - make the hostdata setup act consistently when the device is not added
  - set up the queue depth consistently across these scenarios
  - if the block layer mq support is not available, explicitly enable and
    activate the SCSI layer tcq support (and do this at allocation-time so
    that the tags will be available for INQUIRY commands)

Tweak slave configuration so that devices which are masked are also
not attached.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NHannes Reinecke <hare@Suse.de>
Signed-off-by: NWebb Scales <webbnh@hp.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Add the interrupt number to the interrupt names that
appear in /proc/interrupts, so they are unique

Also, delete the IRQ and DAC prints.  Other parts of the kernel
already print the IRQ assignments, and dual-address-cycle support
has not been interesting since the parallel PCI bus went from
32 to 64 bits wide.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NHannes Reinecke <hare@Suse.de>
Signed-off-by: NRobert Elliott <elliott@hp.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Don't return from the abort request until the target command is complete.
Mark outstanding commands which have a pending abort, and do not send them
to the host if we can avoid it.

If the current command has been aborted, do not call the SCSI command
completion routine from the I/O path: when the abort returns successfully,
the SCSI mid-layer will handle the completion implicitly.

The following race was possible in theory.

1. LLD is requested to abort a scsi command
2. scsi command completes
3. The struct CommandList associated with 2 is made available.
4. new io request to LLD to another LUN re-uses struct CommandList
5. abort handler follows scsi_cmnd->host_scribble and
   finds struct CommandList and tries to aborts it.

Now we have aborted the wrong command.

Fix by resetting the scsi_cmd field of struct CommandList
upon completion and making the abort handler check that
the scsi_cmd pointer in the CommadList struct matches the
scsi_cmnd that it has been asked to abort.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NHannes Reinecke <hare@Suse.de>
Signed-off-by: NWebb Scales <webbnh@hp.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

add support for tmf when in ioaccel2 mode
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NHannes Reinecke <hare@Suse.de>
Signed-off-by: NJoe Handzik <joseph.t.handzik@hp.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Increase the request size for ioaccel2 path.

The error, if any, returned by hpsa_allocate_ioaccel2_sg_chain_blocks
to hpsa_alloc_ioaccel2_cmd_and_bft should be returned upstream rather
than assumed to be -ENOMEM.

This differs slightly from hpsa_alloc_ioaccel1_cmd_and_bft,
which does not call another hpsa_allocate function and only
has -ENOMEM to return from some kmalloc calls.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Signed-off-by: NRobert Elliott <elliott@hp.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

use ioaccel2 path to submit I/O to physical drives in HBA mode
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NHannes Reinecke <hare@Suse.de>
Signed-off-by: NJoe Handzik <joseph.t.handzik@hp.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Do not send aborts to logical devices that do not support aborts

Instead of relying on what the Smart Array claims for supporting logical
drives, simply try an abort and see how it responds at device discovery
time.  This way devices that do support aborts (e.g. MSA2000) can work
and we do not waste time trying to send aborts to logical drives that do
not support them (important for high IOPS devices.)

While rescanning devices only test whether devices support aborts
the first time we encounter a device rather than every time.

Some Smart Arrays required aborts to be sent with tags in
the wrong endian byte order.  To avoid having to know about
this, we would send two aborts with tags with each endian order.
On high IOPS devices, this turns out to be not such a hot idea.
So we now have a list of the devices that got the tag backwards,
and we only send it one way.

If all available commands are outstanding and the abort handler
is invoked, the abort handler may not be able to allocate a command
and may busy-wait excessivly.  Reserve a small number of commands
for the abort handler and limit the number of concurrent abort
requests to the number of reserved commands.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NHannes Reinecke <hare@Suse.de>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Cache the ioaccel handle so that when we need to abort commands sent
down the ioaccel2 path, we can look up the LUN ID in h->dev[] instead of
having to do I/O to the controller.

Add a field to elements in h->dev[] to keep track of how the device is exposed
to the SCSI mid layer: Not at all, without an upper level driver
(no_uld_attach) or normally exposed.

Since masked physical devices are now present in h->dev[] array
it would be perfectly possible to do

	echo scsi add-single-device 2 2 0 0 > /proc/scsi/scsi

and bring them online.  This was previously not allowed for masked
physical devices.

Ensure that the mapping of physical disks to logical drives gets updated in a
consistent way when a RAID migration occurs and is not touched until updates
to it are complete.

now instead of doing CISS_REPORT_PHYSICAL to get the LUNID for
the physical disk in hpsa_get_pdisk_of_ioaccel2(), just get
it out of h->dev[] where we already have it cached.

do not touch phys_disk[] for ioaccel enabled logical drives during rescan
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NKevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NHannes Reinecke <hare@Suse.de>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Suggested-by: NTomas Henzl <thenzl@redhat.com>
Reviewed-by: NWebb Scales <webbnh@hp.com>
Reviewed-by: NKevin Barnett <Kevin.Barnett@pmcs.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Performance tweak, avoid unnecessary function calls.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

No need to check whether interrupt pending for MSI(X) and
conversely, no need to check whether MSI(X) interrupts are
being used when checking if interrupts are pending.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Performance enhancement. Remove spin_locks from the driver.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Empirically, this improves performance slightly (~2% max IOPS) by
allowing cmd_alloc to remember where it left off searching for
free commands between calls instead of always starting its search
at command 0.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Signed-off-by: NRobert Elliott <elliott@hp.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This means changing the allocator to reference count commands.
The reference count is now the authoritative indicator of whether a
command is allocated or not.  The h->cmd_pool_bits bitmap is now
only a heuristic hint to speed up the allocation process, it is no
longer the authoritative record of allocated commands.

Since we changed the command allocator to use reference counting
as the authoritative indicator of whether a command is allocated,
fail_all_outstanding_cmds needs to use the reference count not
h->cmd_pool_bits for this purpose.

Fix hpsa_drain_accel_commands to use the reference count as the
authoritative indicator of whether a command is allocated instead of
the h->cmd_pool_bits bitmap.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

When using the ioaccel submission methods, requests destined for RAID volumes
are sometimes diverted to physical devices.  The OS has no or limited
knowledge of these physical devices, so it is up to the driver to avoid
pushing the device too hard.  It is better to honor the physical device queue
limit rather than making the device spew zillions of TASK SET FULL responses.

This is so that hpsa based devices support /sys/block/sdNN/device/queue_type
of simple, which lets the SCSI midlayer automatically adjust the queue_depth
based on TASK SET FULL and GOOD status.

Adjust the queue depth for a new device after it is created based on the
maximum queue depths of the physical devices that constitute the
device. This drops the maximum queue depth from .can_queue of 1024 to
something like 174 for single-drive RAID-0, 348 for two-drive RAID-1, etc.
It also adjusts for the ratio of data to parity drives.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Signed-off-by: NWebb Scales <webbnh@hp.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Instead of kicking the commands all the way back to the mid
layer, use a work queue.  This enables having a mechanism for
the driver to be able to resubmit the commands down the "normal"
raid path without turning off the ioaccel feature entirely
whenever an error is encountered on the ioaccel path, and
prevent excessive rescanning of devices.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The original reasoning behind doing this was faulty.  An error
of some sort would be encountered, accelerated i/o would be
disabled for that logical drive, the command would be kicked
back out to the SCSI midlayer for a retry, and since i/o accelerator
mode was disabled, it would get retried down the RAID path.
However, something needs to turn ioaccellerator mode back on,
and this rescan request was what did that.  However, it was racy,
and extremely bad for performance to rescan all devices, so,
don't do that.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

By not doing maintaining a list of queued commands, we can eliminate some spin
locking in the main i/o path and gain significant improvement in IOPS.  Remove
the queuing code and the code that calls it; remove now-unused interrupt code;
remove DIRECT_LOOKUP_BIT.

Now that the passthru commands share the same command pool as
the main i/o path, and the total size of the pool is less than
or equal to the number of commands that will fit in the hardware
fifo, there is no need to check to see if we are exceeding the
hardware fifo's depth.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Reviewed-by: NRobert Elliott <elliott@hp.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

We have commands reserved for internal use.

This is laying the groundwork for removing the internal
queue of commands from the driver so that the locks that
protect that queue may be removed.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

We need to reserve some commands for device rescans,
aborts, and the pass through ioctls, etc. so we cannot
give them all to the scsi mid layer.

This is in preparation for removing cmd_special_alloc and
cmd_special_free so that we can stop queuing commands internally
in the driver so that we can remove the locks thta protect the
queue that we will no longer have.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>