This patch implements q->lld_busy_fn() for scsi mid layer to export
its busy state for request stacking drivers.

For efficiency, no lock is taken to check the busy state of
shost/starget/sdev, since the returned value is not guaranteed and
may be changed after request stacking drivers call the function,
regardless of taking lock or not.

When scsi can't dispatch I/Os anymore and needs to kill I/Os
(e.g. !sdev), scsi needs to return 'not busy'.
Otherwise, request stacking drivers may hold requests forever.
Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This patch refactors the busy checking codes of scsi_device,
Scsi_Host and scsi_target.  There should be no functional change.

This is a preparation for another patch which exports scsi's busy
state to the block layer for request stacking drivers.
Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

On Tue, 12 Aug 2008 15:08:14 +0200
Giuliano Pochini <pochini@shiny.it> wrote:

> Fujitsu magneto-optical drive, Adaptec 29160 and
> Linux Jay 2.6.26 #7 SMP Sun Aug 10 18:34:22 CEST 2008 ppc 7455, altivec supported PowerMac3,6 GNU/Linux
>
> When I insert a disk and I mount it, scsi_test_unit_ready() is called and
> the do-while loop gets sshdr->sense_key == UNIT_ATTENTION in the first
> cycle and 0 in the second one. So the if below misses the UNIT_ATTENTION
> and sdev->changed = 1 is not executed. At this point bad things can
> happen... I'm not sure how to fix this. Any clue ?

The problem is essentially caused by us eating UNIT_ATTENTION
conditions in scsi_test_unit_ready().  Fix by updating the ->changed
flag when this happens if the media is removable.

[pochini@shiny.it: updates to tidy up patch]
Signed-off-by: NGiuliano Pochini <pochini@shiny.it>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This checks the errors the scsi-ml determined were retryable
and returns if we should fast fail it based on the request
fail fast flags.

Without the patch, drivers like lpfc, qla2xxx and fcoe would return
DID_ERROR for what it determines is a temporary communication problem.
There is no loss of connectivity at that time and the driver thinks
that it would be fast to retry at the driver level. SCSI-ml will however
sees fast fail on the request and DID_ERROR and will fast fail the io.
This will then cause dm-multipath to fail the path and possibley switch
target controllers when we should be retrying at the scsi layer.

We also were fast failing device errors to dm multiapth when
unless the scsi_dh modules think otherwis we want to retry at
the scsi layer because multipath can only retry the IO like scsi
should have done. multipath is a little dumber though because it
does not what the error was for and assumes that it should fail
the paths.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

SCSI-ml manages the queueing limits for the device and host, but
does not do so at the target level. However something something similar
can come in userful when a driver is transitioning a transport object to
the the blocked state, becuase at that time we do not want to queue
io and we do not want the queuecommand to be called again.

The patch adds code similar to the exisiting SCSI_ML_*BUSY handlers.
You can now return SCSI_MLQUEUE_TARGET_BUSY when we hit
a transport level queueing issue like the hw cannot allocate some
resource at the iscsi session/connection level, or the target has temporarily
closed or shrunk the queueing window, or if we are transitioning
to the blocked state.

bnx2i, when they rework their firmware according to netdev
developers requests, will also need to be able to limit queueing at this
level. bnx2i will hook into libiscsi, but will allocate a scsi host per
netdevice/hba, so unlike pure software iscsi/iser which is allocating
a host per session, it cannot set the scsi_host->can_queue and return
SCSI_MLQUEUE_HOST_BUSY to reflect queueing limits on the transport.

The iscsi class/driver can also set a scsi_target->can_queue value which
reflects the max commands the driver/class can support. For iscsi this
reflects the number of commands we can support for each session due to
session/connection hw limits, driver limits, and to also reflect the
session/targets's queueing window.

Changes:
v1 - initial patch.
v2 - Fix scsi_run_queue handling of multiple blocked targets.
Previously we would break from the main loop if a device was added back on
the starved list. We now run over the list and check if any target is
blocked.
v3 - Rediff for scsi-misc.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Right now SCSI and others do their own command timeout handling.
Move those bits to the block layer.

Instead of having a timer per command, we try to be a bit more clever
and simply have one per-queue. This avoids the overhead of having to
tear down and setup a timer for each command, so it will result in a lot
less timer fiddling.
Signed-off-by: NMike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Brian King <brking@linux.vnet.ibm.com> reported that fibre channel
devices can oops during scanning if their ports block (because the
device goes from CREATED -> BLOCK -> RUNNING rather than CREATED ->
BLOCK -> CREATED).

Fix this by adding a new state: CREATED_BLOCK which can only transition
back to CREATED and disallow the CREATED -> BLOCK transition.  Now both
the created and blocked states that the mid-layer recognises can include
CREATED_BLOCK.
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Sometimes, particularly for USB devices with the last sector bug,
requests get completed in chunks.  There's a bug in this in that if
one of the chunks gets an error, we complete that chunk with an error
but never move on to the remaining ones, leading to the request
hanging (because it's not fully completed).

Fix this by completing all remaining chunks if an error is encountered.

Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

[jejb: fixed up a ton of missed conversions.

 All of you are on notice this has happened, driver trees will now
 need to be rebased]
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Cc: SCSI List <linux-scsi@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

I goofed and did not see the macro for checking if a request is tagged.
This patch has us use blk_rq_tagged instead of digging into the req->tag.

Patch was made over scsi-misc.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

If initiator or target reject the I/O due to DIF errors there is no
point in retrying.
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Implement support for DMA of protection information for devices that
are data integrity capable.

 - Add support for mapping an extra scatter-gather list containing
   the protection information.

 - Allocate protection scsi_data_buffer if host is DIX (integrity DMA)
   capable.

 - Accessor function for checking whether a device has protection
   enabled.
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

When drivers use a shared tag map we can end up with more requests
than tags, because the tag map is shost->can_queue tags and there
can be sdevs * sdev->queue_depth requests. In scsi_request_fn
if tag allocation fails we just drop down to just dequeueing the
tag without a tag. The problem is that drivers using the shared tag
map rely on a valid tag always being set, because it will use the
tag number to lookup commands later.

This patch has us check if we got a valid tag when the host lock
is held right before we check if the host queue is ready. We do the
check here because to allocate the tag we need the q lock, but
if the tag is bad we want to add the device/q onto the starved list
which requires the host lock.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

scsi_lib.c:scsi_host_queue_ready() plugs the device with incorrect
locking.  It should actually have the queue lock held, but it's
holding the host lock.  Fix this by eliminating the call.  The host
ready has no need to plug the queue because if it returns 0 in
scsi_request_function control transfers to not_ready which acquires
the queue lock and plugs the device if its at zero depth.
Reported-by: NElias Oltmanns <eo@nebensachen.de>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

The data integrity changes need to dynamically allocate
scsi_data_buffers too.  Rename scsi_bidi_sdb_cache for clarity.
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This patch (as1108) fixes a problem that can occur with certain USB
mass-storage devices: They return invalid data together with a residue
indicating that the data should be ignored.  Rather than leave the
invalid data in a transfer buffer, where it can get misinterpreted,
the patch clears the invalid portion of the buffer.

This solves a problem (wrong write-protect setting detected) reported
by Maciej Rutecki and Peter Teoh.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Tested-by: Peter Teoh <htmldeveloper@gmail.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Some of the storage devices (that can be accessed through multiple paths),
do need some special handling for
	1. Activating the passive path of the storage access.
	2. Decode and handle the special sense codes returned by the devices.
	3. Handle the I/Os being sent to the passive path, especially
           during the device probe time.
when accessed through multiple paths.

As of today this special device handling is done at the dm-multipath
layer using dm-handlers. That works well for (1); for (2) to be handled
at dm layer, scsi sense information need to be exported from SCSI to dm-layer,
which is not very attractive; (3) cannot be done at all at the dm layer.

Device handler has been moved to SCSI mainly to handle (2) and (3) properly.
Signed-off-by: NChandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: NMike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Add support for variable-length, extended, and vendor specific
CDBs to scsi-ml. It is now possible for initiators and ULD's
to issue these types of commands. LLDs need not change much.
All they need is to raise the .max_cmd_len to the longest command
they support (see iscsi patch).

- clean-up some code paths that did not expect commands to be
  larger than 16, and change cmd_len members' type to short as
  char is not enough.
Signed-off-by: NBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

 - struct scsi_cmnd had a 16 bytes command buffer of its own.
   This is an unnecessary duplication and copy of request's
   cmd. It is probably left overs from the time that scsi_cmnd
   could function without a request attached. So clean that up.

 - Once above is done, few places, apart from scsi-ml, needed
   adjustments due to changing the data type of scsi_cmnd->cmnd.

 - Lots of drivers still use MAX_COMMAND_SIZE. So I have left
   that #define but equate it to BLK_MAX_CDB. The way I see it
   and is reflected in the patch below is.
   MAX_COMMAND_SIZE - means: The longest fixed-length (*) SCSI CDB
                      as per the SCSI standard and is not related
                      to the implementation.
   BLK_MAX_CDB.     - The allocated space at the request level

 - I have audit all ISA drivers and made sure none use ->cmnd in a DMA
   Operation. Same audit was done by Andi Kleen.

(*)fixed-length here means commands that their size can be determined
   by their opcode and the CDB does not carry a length specifier, (unlike
   the VARIABLE_LENGTH_CMD(0x7f) command). This is actually not exactly
   true and the SCSI standard also defines extended commands and
   vendor specific commands that can be bigger than 16 bytes. The kernel
   will support these using the same infrastructure used for VARLEN CDB's.
   So in effect MAX_COMMAND_SIZE means the maximum size command
   scsi-ml supports without specifying a cmd_len by ULD's
Signed-off-by: NBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

We can save some atomic ops in the IO path, if we clearly define
the rules of how to modify the queue flags.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Currently, if the barrier command fails, the error return isn't seen
by the block layer and it proceeds on regardless.  The problem is that
SCSI always returns no error for REQ_TYPE_BLOCK_PC ... it expects the
submitter to pick the errors out of req->errors, which the block
barrier functions don't do.

Since it appears that the way SG_IO and scsi_execute_request() work
they discard the block error return and always use req->errors, the
best fix for this is to have the SCSI layer return an error to block
if one actually occurred (this also allows us to filter out spurious
errors, like deferred sense).

This patch is a bug fix that will need backporting to stable, but it's
also quite a big change and in need of testing, so we'll incubate in
the main kernel tree and backport at the -rc2 or so stage if no
problems turn up.
Acked-by: NJens Axboe <jens.axboe@oracle.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This patch makes the needlessly global scsi_end_bidi_request() static.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Acked-by: NBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Commit:
  a341cd0f (SCSI: add asynchronous event notification API)
breaks:
  285e9670 (sr,sd: send media state change modification events)
by introducing an event filter, which is removed here, to make
events, we are depending on, happen again.

Fix this by removing the event filter.  It's pretty much broken at the
moment, since a user can't set it (the attribute being read only).  A
proper fix will be to make the event discriminator distinguish between
AN and Polled media change events.

Cc: David Zeuthen <david@fubar.dk>
Cc: kristen accardi <kaccardi@gmail.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

With padding and draining moved into it, block layer now may extend
requests as directed by queue parameters, so now a request has two
sizes - the original request size and the extended size which matches
the size of area pointed to by bios and later by sgs.  The latter size
is what lower layers are primarily interested in when allocating,
filling up DMA tables and setting up the controller.

Both padding and draining extend the data area to accomodate
controller characteristics.  As any controller which speaks SCSI can
handle underflows, feeding larger data area is safe.

So, this patch makes the primary data length field, request->data_len,
indicate the size of full data area and add a separate length field,
request->raw_data_len, for the unmodified request size.  The latter is
used to report to higher layer (userland) and where the original
request size should be fed to the controller or device.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

When sending a SCSI command to a tape drive via the SCSI Generic (sg)
driver, if the command has a data transfer length more than
scatter_elem_sz (32 KB default) and not a multiple of 512, then I either
hit BUG_ON(!valid_dma_direction(direction)) in dma_unmap_sg() or else
the command never completes (depending on the LLDD).

When constructing scatterlists, the sg driver rounds up the scatterlist
element sizes to be a multiple of 512.  This can result in
sum(scatterlist lengths) > bufflen.  In this case, scsi_req_map_sg()
incorrectly sets bio->bi_size to sum(scatterlist lengths) rather than to
bufflen.  When the command completes, req_bio_endio() detects that
bio->bi_size != 0, and so it doesn't call bio_endio().  This causes the
command to be resubmitted, resulting in BUG_ON or the command never
completing.

This patch makes scsi_req_map_sg() set bio->bi_size to bufflen rather
than to sum(scatterlist lengths), which fixes the problem.
Signed-off-by: NTony Battersby <tonyb@cybernetics.com>
Acked-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This is a one-line patch to add the following to __scsi_alloc_queue():

dma_set_seg_boundary(dev, shost->dma_boundary);

This is the simplest approach but the result looks odd,
__scsi_alloc_queue() does:

blk_queue_segment_boundary(q, shost->dma_boundary);
dma_set_seg_boundary(dev, shost->dma_boundary);
blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));

I think that it would be better to set up segment boundary in the same
way as we did for the maximum segment size. That is, removing
shost->dma_boundary and LLDs call pci_set_dma_seg_boundary (or its
friends).

Then __scsi_alloc_queue() can set up both limits in the same way:

blk_queue_segment_boundary(q, dma_get_seg_boundary(dev));
blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));

killing dma_boundary in scsi_host_template needs a large patch for
libata (dma_boundary is used by only libata and sym53c8xx). I'll send
a patch to do that if it is acceptable. James and Jeff?
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

request_queue and device struct must have the same value of a segment
size limit. This patch adds blk_queue_segment_boundary in
__scsi_alloc_queue so LLDs don't need to call both
blk_queue_segment_boundary and set_dma_max_seg_size. A LLD can change
the default value (64KB) can call device_dma_parameters accessors like
pci_set_dma_max_seg_size when allocating scsi_host.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: NJeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Acked-by: NJens Axboe <jens.axboe@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

scsi_init_queue is expected to clean up allocated things when it
fails.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Needs to call kmem_cache_destroy for scsi_bidi_sdb_cache in
scsi_exit_queue.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

With the sg table code, every SCSI driver is now either chain capable
or broken (or has sg_tablesize set so chaining is never activated), so
there's no need to have a check in the host template.

Also tidy up the code by moving the scatterlist size defines into the
SCSI includes and permit the last entry of the scatterlist pools not
to be a power of two.
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

At the block level bidi request uses req->next_rq pointer for a second
bidi_read request.
At Scsi-midlayer a second scsi_data_buffer structure is used for the
bidi_read part. This bidi scsi_data_buffer is put on
request->next_rq->special. Struct scsi_cmnd is not changed.

- Define scsi_bidi_cmnd() to return true if it is a bidi request and a
  second sgtable was allocated.

- Define scsi_in()/scsi_out() to return the in or out scsi_data_buffer
  from this command This API is to isolate users from the mechanics of
  bidi.

- Define scsi_end_bidi_request() to do what scsi_end_request() does but
  for a bidi request. This is necessary because bidi commands are a bit
  tricky here. (See comments in body)

- scsi_release_buffers() will also release the bidi_read scsi_data_buffer

- scsi_io_completion() on bidi commands will now call
  scsi_end_bidi_request() and return.

- The previous work done in scsi_init_io() is now done in a new
  scsi_init_sgtable() (which is 99% identical to old scsi_init_io())
  The new scsi_init_io() will call the above twice if needed also for
  the bidi_read command. Only at this point is a command bidi.

- In scsi_error.c at scsi_eh_prep/restore_cmnd() make sure bidi-lld is not
  confused by a get-sense command that looks like bidi. This is done
  by puting NULL at request->next_rq, and restoring.

[jejb: update to sg_table and resolve conflicts
also update to blk-end-request and resolve conflicts]
Signed-off-by: NBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

In preparation for bidi we abstract all IO members of scsi_cmnd,
that will need to duplicate, into a substructure.

- Group all IO members of scsi_cmnd into a scsi_data_buffer
  structure.
- Adjust accessors to new members.
- scsi_{alloc,free}_sgtable receive a scsi_data_buffer instead of
  scsi_cmnd. And work on it.
- Adjust scsi_init_io() and  scsi_release_buffers() for above
  change.
- Fix other parts of scsi_lib/scsi.c to members migration. Use
  accessors where appropriate.

- fix Documentation about scsi_cmnd in scsi_host.h

- scsi_error.c
  * Changed needed members of struct scsi_eh_save.
  * Careful considerations in scsi_eh_prep/restore_cmnd.

- sd.c and sr.c
  * sd and sr would adjust IO size to align on device's block
    size so code needs to change once we move to scsi_data_buff
    implementation.
  * Convert code to use scsi_for_each_sg
  * Use data accessors where appropriate.

- tgt: convert libsrp to use scsi_data_buffer

- isd200: This driver still bangs on scsi_cmnd IO members,
  so need changing

[jejb: rebased on top of sg_table patches fixed up conflicts
and used the synergy to eliminate use_sg and sg_count]
Signed-off-by: NBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

If we export scsi_init_io()/scsi_release_buffers() instead of
scsi_{alloc,free}_sgtable() from scsi_lib than tgt code is much more
insulated from scsi_lib changes. As a bonus it will also gain bidi
capability when it comes.

[jejb: rebase on to sg_table and fix up rejections]
Signed-off-by: NBoaz Harrosh <bharrosh@panasas.com>
Acked-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

SCSI sg table allocation has a maximum size (of SCSI_MAX_SG_SEGMENTS,
currently 128) and this will cause a BUG_ON() in SCSI if something
tries an allocation over it.  This patch adds a size limit to the
chaining allocator to allow the specification of the maximum
allocation size for chaining, so we always chain in units of the
maximum SCSI allocation size.
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

This patch converts scsi mid-layer to use blk_end_request interfaces.
Related 'uptodate' arguments are converted to 'error'.

As a result, the interface of internal function, scsi_end_request(),
is changed.

Cc: James Bottomley <James.Bottomley@SteelEye.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Also change scsi_alloc_sgtable() to just return 0/failure, since it
maps to the command passed in. ->request_buffer is now no longer needed,
once drivers are adapted to use scsi_sglist() it can be killed.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

This replaces sizeof sense_buffer with SCSI_SENSE_BUFFERSIZE in
several LLDs. It's a preparation for the future changes to remove
sense_buffer array in scsi_cmnd structure.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This patch relaxes the default SCSI DMA alignment from 512 bytes to 4
bytes.  I remember from previous discussions that usb and firewire have
sector size alignment requirements, so I upped their alignments in the
respective slave allocs.

The reason for doing this is so that we don't get such a huge amount of
copy overhead in bio_copy_user() for udev.  (basically all inquiries it
issues can now be directly mapped).
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

The current scsi_test_unit_ready() is updated to return sense code
information (in struct scsi_sense_hdr).  The sd and sr drivers are
changed to interpret the sense code return asc 0x3a as no media and
adjust the device status accordingly.
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>