rq->data_len served two purposes - the length of data buffer on issue
and the residual count on completion.  This duality creates some
headaches.

First of all, block layer and low level drivers can't really determine
what rq->data_len contains while a request is executing.  It could be
the total request length or it coulde be anything else one of the
lower layers is using to keep track of residual count.  This
complicates things because blk_rq_bytes() and thus
[__]blk_end_request_all() relies on rq->data_len for PC commands.
Drivers which want to report residual count should first cache the
total request length, update rq->data_len and then complete the
request with the cached data length.

Secondly, it makes requests default to reporting full residual count,
ie. reporting that no data transfer occurred.  The residual count is
an exception not the norm; however, the driver should clear
rq->data_len to zero to signify the normal cases while leaving it
alone means no data transfer occurred at all.  This reverse default
behavior complicates code unnecessarily and renders block PC on some
drivers (ide-tape/floppy) unuseable.

This patch adds rq->resid_len which is used only for residual count.

While at it, remove now unnecessasry blk_rq_bytes() caching in
ide_pc_intr() as rq->data_len is not changed anymore.

Boaz	: spotted missing conversion in osd
Sergei	: spotted too early conversion to blk_rq_bytes() in ide-tape

[ Impact: cleanup residual count handling, report 0 resid by default ]
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Mike Miller <mike.miller@hp.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: Mike Miller <mike.miller@hp.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Cc: Darrick J. Wong <djwong@us.ibm.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

for SAS drivers.

Caught by Ke Wei (and team?) at Marvell.

Also, move the ata_scsi_ioctl export to libata-scsi.c, as that seems to be the
general trend.
Acked-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

unsigned req->data_len cannot be negative, and fix =-/-= typo
Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

[jejb: limit ioctl to returning 20 characters to avoid overrun
       on long device names and add a few more conversions]
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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>

Logically, SCR access ops should take @link; however, there was no
compelling reason to convert all SCR access ops when adding @link
abstraction as there's one-to-one mapping between a port and a non-PMP
link.  However, that assumption won't hold anymore with the scheduled
addition of slave link.

Make SCR access ops per-link.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJeff Garzik <jgarzik@redhat.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>

Now that SFF assumptions are separated out from non-SFF reset
sequence, port_ops->sff_dev_select() is no longer necessary for
non-SFF controllers.  Kill ata_noop_dev_select() and ->sff_dev_select
initialization from base and other non-SFF port_ops.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Now that all SFF stuff is separated out of core layer, core layer
doesn't call ops->[alt_]check_status().  In fact, no one calls them
for non-SFF drivers anymore.  Kill them.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Now that all SFF stuff is separated out of core layer, core layer
doesn't call ops->tf_read directly.  It gets called only via
ops->qc_fill_rtf() for non-SFF drivers.  This patch directly
implements private ops->qc_fill_rtf() for non-SFF controllers and kill
ops->tf_read().

This is much cleaner for non-SFF controllers as some of them have to
cache SFF register values in private data structure and report the
cached values via ops->tf_read().  Also, ops->tf_read() gets nasty for
controllers which don't have clear notion of TF registers when
operation is not in progress.

As this change makes default ops->qc_fill_rtf unnecessary, move
ata_sff_qc_fill_rtf() form ata_base_port_ops to ata_sff_port_ops where
it belongs.
Signed-off-by: NTejun Heo <htejun@gmail.com>

On command completion, ata_qc_complete() directly called ops->tf_read
to fill qc->result_tf.  This patch adds ops->qc_fill_rtf to replace
hardcoded ops->tf_read usage.

ata_sff_qc_fill_rtf() which uses ops->tf_read to fill result_tf is
implemented and set in ata_base_port_ops and other ops tables which
don't inherit from ata_base_port_ops, so this patch doesn't introduce
any behavior change.

ops->qc_fill_rtf() is similar to ops->sff_tf_read() but can only be
called when a command finishes.  As some non-SFF controllers don't
have TF registers defined unless they're associated with in-flight
commands, this limited operation makes life easier for those drivers
and help lifting SFF assumptions from libata core layer.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Add sff_ prefix to SFF specific port ops.

This rename is in preparation of separating SFF support out of libata
core layer.  This patch strictly renames ops and doesn't introduce any
behavior difference.
Signed-off-by: NTejun Heo <htejun@gmail.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Provide a facility to use the request_firmware() interface to get a SAS
address from userspace.  This can be used by SAS LLDDs that cannot
obtain the address from the host adapter.
Signed-off-by: NDarrick J. Wong <djwong@us.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

We give a very cryptic error if an ATA device is seen on a SAS port
but libsas isn't compiled to include libata to handle them.  Add an
extra warning to explain specifically what the problem is.
Acked-by: NDarrick J. Wong <djwong@us.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

- Correct one use after free of the sas task
- update the reset required path to move straight to LUN reset
- make the bigger hammer actually reset something instead of just trying
  to clear all the tasks.
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Once the phy reset is plumbed in properly, SATA error handling fails
nastily because we change the port attached_sas_address using the WWN
field of the IDENTIFY message.  This is a nice thing to do in theory,
but it really destroys hotplug because any event on the port causes an
automatic mismatch between the sas_address the phy just picked up and
the one we propagate into the port.  However ugly they are, we have to
stick with the sas addresses made up by the phys and expanders.

Also does a few cosmetic changes to the way port printing is done to
make it clearer how a port is formed.
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This is needed by the to be added I_T reset function in aic94xx.  It
needs to know the local phy so it can send a link or hard reset along
the path.
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

The current sas_scsi_clear_queue_lu() is wrongly checking for commands
which match the pointer to the one passed in.  It should be checking for
commands which are on the same logical unit as the one passed in.  Fix
this by checking target pointer and LUN for equality.
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

The libsas error handler has two fairly fatal bugs

1. scsi_sas_task_done calls scsi_eh_finish_cmd() too early.  This
   happens if the task completes after it has been aborted but before
   the error handler starts up.  Because scsi_eh_finish_cmd()
   decrements host_failed and adds the task to the done list, the
   error handler start check (host_failed == host_busy) never passes
   and the eh never starts.

2. The multiple task completion paths sas_scsi_clear_queue_... all
   simply delete the task from the error queue.  This causes it to
   disappear into the ether, since a command must be placed on the
   done queue to be finished off by the error handler.  This behaviour
   causes the HBA to hang on pending commands.

Fix 1. by moving the SAS_TASK_STATE_ABORTED check to an exit clause at
the top of the routine and calling ->scsi_done() unconditionally (it
is a nop if the timer has fired).  This keeps the task in the error
handling queue until the eh starts.

Fix 2. by making sure every task goes through task complete followed
by scsi_eh_finish_cmd().

Tested this by firing resets across a disk running a hammer test (now
it actually survives without hanging the system)
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

that provided by the block layer

ATA requires that all DMA transfers begin and end on word boundaries.
Because of this, a large amount of machinery grew up in ide to adjust
scatterlists on this basis.  However, as of 2.5, the block layer has a
dma_alignment variable which ensures both the beginning and length of a
DMA transfer are aligned on the dma_alignment boundary.  Although the
block layer does adjust the beginning of the transfer to ensure this
happens, it doesn't actually adjust the length, it merely makes sure
that space is allocated for transfers beyond the declared length.  The
upshot of this is that scatterlists may be padded to any size between
the actual length and the length adjusted to the dma_alignment safely
knowing that memory is allocated in this region.

Right at the moment, SCSI takes the default dma_aligment which is on a
512 byte boundary.  Note that this aligment only applies to transfers
coming in from user space.  However, since all kernel allocations are
automatically aligned on a minimum of 32 byte boundaries, it is safe to
adjust them in this manner as well.

tj: * Adjusting sg after padding is done in block layer.  Make libata
      set queue alignment correctly for ATAPI devices and drop broken
      sg mangling from ata_sg_setup().
    * Use request->raw_data_len for ATAPI transfer chunk size.
    * Killed qc->raw_nbytes.
    * Separated out killing qc->n_iter.
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Break out the frame processor for STP tasks from aic94xx so they can
be shared by other SAS HBA's

Original patch from Jeff Garzik <jeff@garzik.org>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

All kobjects require a dynamically allocated name now. We no longer
need to keep track if the name is statically assigned, we can just
unconditionally free() all kobject names on cleanup.
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

LLDs don't need to zero out scsi_cmnd::sense_buffer in queuecommand
since scsi-ml does. This is a preparation of the future changes to
allocate the sense_buffer only when necessary.

Many LLDs zero out the sense_buffer before touching it on the error
case. This patch lets them alone for now because new APIs for them
would be added later on.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: N"Salyzyn, Mark" <Mark_Salyzyn@adaptec.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

libata used private sg iterator to handle padding sg.  Now that sg can
be chained, padding can be handled using standard sg ops.  Convert to
chained sg.

* s/qc->__sg/qc->sg/

* s/qc->pad_sgent/qc->extra_sg[]/.  Because chaining consumes one sg
  entry.  There need to be two extra sg entries.  The renaming is also
  for future addition of other extra sg entries.

* Padding setup is moved into ata_sg_setup_extra() which is organized
  in a way that future addition of other extra sg entries is easy.

* qc->orig_n_elem is unused and removed.

* qc->n_elem now contains the number of sg entries that LLDs should
  map.  qc->mapped_n_elem is added to carry the original number of
  mapped sgs for unmapping.

* The last sg of the original sg list is used to chain to extra sg
  list.  The original last sg is pointed to by qc->last_sg and the
  content is stored in qc->saved_last_sg.  It's restored during
  ata_sg_clean().

* All sg walking code has been updated.  Unnecessary assertions and
  checks for conditions the core layer already guarantees are removed.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

ATA_PROT_ATAPI_* are ugly and naming schemes between ATA_PROT_* and
ATA_PROT_ATAPI_* are inconsistent causing confusion.  Rename them to
ATAPI_PROT_* and make them consistent with ATA counterpart.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Implement protocol tests - ata_is_atapi(), ata_is_nodata(),
ata_is_pio(), ata_is_dma(), ata_is_ncq() and ata_is_data() and use
them to replace is_atapi_taskfile() and hard coded protocol tests.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

This is bad for two reasons:

     1. If they're returned to outside applications, no-one knows what
        they mean.
     2. Eventually they'll clash with the ever expanding standard error
        codes.

The problem error code in question is ETASK.  I've replaced this by
ECOMM (communications error on send) a network error code that seems to
most closely relay what ETASK meant.
Acked-by: NDarrick J. Wong <djwong@us.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

All SMP tasks sent through bsg generate messages like:

sas: smp_execute_task: task to dev 500605b000001450 response: 0x0 status 0x81

Three times (because the task gets retried).  Firstly, don't retry
either overrun or underrun (the data buffer isn't going to change size)
and secondly, just report the underrun but don't set an error for it.
This is necessary so bsg can report back the residual.
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This adds support for host side SMP processing, via a separate
SMP interpreter file.
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Annotate sas_queuecommand with locking details, and clean up a few
more sparse warnings about static/non-static declarations.
Signed-off-by: NDarrick J. Wong <djwong@us.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

sparse complains about the mixing of enums in libsas.  Since the
underlying numeric values of both enums are the same, combine them
to get rid of the warning.
Signed-off-by: NDarrick J. Wong <djwong@us.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

The task_struct->pid member is going to be deprecated, so start
using the helpers (task_pid_nr/task_pid_vnr/task_pid_nr_ns) in
the kernel.

The first thing to start with is the pid, printed to dmesg - in
this case we may safely use task_pid_nr(). Besides, printks produce
more (much more) than a half of all the explicit pid usage.

[akpm@linux-foundation.org: git-drm went and changed lots of stuff]
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It was always set to ata_port_disable().  Removed the hook, and replaced
the very few ap->ops->port_disable() callsites with direct calls to
ata_port_disable().
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Introduce ata_link.  It abstracts PHY and sits between ata_port and
ata_device.  This new level of abstraction is necessary to support
SATA Port Multiplier, which basically adds a bunch of links (PHYs) to
a ATA host port.  Fields related to command execution, spd_limit and
EH are per-link and thus moved to ata_link.

This patch only defines the host link.  Multiple link handling will be
added later.  Also, a lot of ap->link derefences are added but many of
them will be removed as each part is converted to deal directly with
ata_link instead of ata_port.

This patch introduces no behavior change.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Cc: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

If you have the libsas with ATA support, it needs libata to function.
The problem is that if you compile in libsas, you can't build libata
as a module (however, vice versa you can).
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

In sas_smp_get_phy_events() we never test if the call to
alloc_smp_req(RPEL_REQ_SIZE) succeeds or fails. That means we run
the risk of dereferencing a NULL pointer if it does fail. Far
better to test if we got NULL back and in that case return -ENOMEM
just as we already do for the other memory allocation in that
function.
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Eliminate unnecessary PCI dependencies in libsas.  It should use generic
DMA and struct device like other subsystems.
Signed-off-by: NJeff Garzik <jeff@garzik.org>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

sas_smp_handler crashes when smp utils are used with an aic94xx host
because certain devices (the sas_host itself, specifically) lack rphy
structures.  No rphy means no SMP target support, but we shouldn't crash
here.
Signed-off-by: NDarrick J. Wong <djwong@us.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>