sbp2_release_target() is folded into its primary user, sbp2_remove().
The only other caller, a failure path in sbp2_probe(), now uses
sbp2_remove().  This adds unnecessary cancel_delayed_work_sync() calls
to that failure path but results in less code and text.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Implement sbp2_queue_work(), which is now a very simple accessor to one
of the struct sbp2_logical_unit members, right after the definition of
struct sbp2_logical_unit.

Put the sbp2_reconnect() implementation right after the sbp2_login()
implementation.  They are both part of the SBP-2 access protocol.

Implement the driver methods sbp2_probe(), spp2_update(), sbp2_remove()
in this order, reflecting the lifetime of an SBP-2 target.

Place the sbp2_release_target() implementation right next to
sbp2_remove() which is its primary user, and after sbp2_probe() which is
the counterpart to sbp2_release_target().

There are no changes to the implementations here, or at least not meant
to be.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Since commit 0278ccd9 "firewire: sbp2:
fix panic after rmmod with slow targets", the lifetime of an sbp2_target
instance does no longer extent past the return of sbp2_remove().
Therefore it is no longer necessary to call fw_unit_get/put() and
fw_device_get/put() in sbp2_probe/remove().

Furthermore, said commit also ensures that lu->work is not going to be
executed or requeued at a time when the sbp2_target is no longer in use.
Hence there is no need for sbp2_target reference counting for lu->work.

Other concurrent contexts:

  - Processes which access the sysfs of the SCSI host device or of one
    of its subdevices are safe because these interfaces are all removed
    by scsi_remove_device/host() in sbp2_release_target().

  - SBP-2 command block ORB transactions are finished when
    scsi_remove_device() in sbp2_release_target() returns.

  - SBP-2 management ORB transactions are finished when
    cancel_delayed_work_sync(&lu->work) before sbp2_release_target()
    returns.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

If firewire-sbp2 starts a login to a target that doesn't complete ORBs
in a timely manner (and has to retry the login), and the module is
removed before the operation times out, you end up with a null-pointer
dereference and a kernel panic.

[SR:  This happens because sbp2_target_get/put() do not maintain
module references.  scsi_device_get/put() do, but at occasions like
Chris describes one, nobody holds a reference to an SBP-2 sdev.]

This patch cancels pending work for each unit in sbp2_remove(), which
hopefully means there are no extra references around that prevent us
from unloading. This fixes my crash.
Signed-off-by: NChris Boot <bootc@bootc.net>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The struct sbp2_logical_unit.work items can all be executed in parallel
but are not reentrant.  Furthermore, reconnect or re-login work must be
executed in a WQ_MEM_RECLAIM workqueue.

Hence replace the old single-threaded firewire-sbp2 workqueue by a
concurrency-managed but non-reentrant workqueue with rescuer.
firewire-core already maintains one, hence use this one.

In earlier versions of this change, I observed occasional failures of
parallel INQUIRY to an Initio INIC-2430 FireWire 800 to dual IDE bridge.
More testing indicates that parallel INQUIRY is not actually a problem,
but too quick successions of logout and login + INQUIRY, e.g. a quick
sequence of cable plugout and plugin, can result in failed INQUIRY.
This does not seem to be something that should or could be addressed by
serialization.

Another dual-LU device to which I currently have access to, an
OXUF924DSB FireWire 800 to dual SATA bridge with firmware from MacPower,
has been successfully tested with this too.

This change is beneficial to environments with two or more FireWire
storage devices, especially if they are located on the same bus.
Management tasks that should be performed as soon and as quickly as
possible, especially reconnect, are no longer held up by tasks on other
devices that may take a long time, especially login with INQUIRY and sd
or sr driver probe.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

We do not need slab allocations for ORB pointer write transactions
anymore in order to satisfy streaming DMA mapping constraints, thanks to
commit da28947e "firewire: ohci: avoid separate DMA mapping for
small AT payloads".

(Besides, the slab-allocated buffers that firewire-sbp2 used to provide
for 8-byte write requests were still not fully portable since they
shared a cacheline with unrelated CPU-accessed data.)
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

firewire-sbp2 already takes care for internal serialization where
required (ORB list accesses), and it does not use cmd->serial_number
internally.  Hence it is safe to not grab the shost lock around
queuecommand.

While we are at housekeeping, drop a redundant struct member:
sbp2_command_orb.done is set once in a hot path and dereferenced once in
a hot path.  We can as well dereference sbp2_command_orb.cmd->scsi_done
instead.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Now that firewire-core sets the local node's SPLIT_TIMEOUT to 2 seconds
per default, commit a481e97d is no
longer required.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Move the mid-layer's ->queuecommand() invocation from being locked
with the host lock to being unlocked to facilitate speeding up the
critical path for drivers who don't need this lock taken anyway.

The patch below presents a simple SCSI host lock push-down as an
equivalent transformation.  No locking or other behavior should change
with this patch.  All existing bugs and locking orders are preserved.

Additionally, add one parameter to queuecommand,
	struct Scsi_Host *
and remove one parameter from queuecommand,
	void (*done)(struct scsi_cmnd *)

Scsi_Host* is a convenient pointer that most host drivers need anyway,
and 'done' is redundant to struct scsi_cmnd->scsi_done.

Minimal code disturbance was attempted with this change.  Most drivers
needed only two one-line modifications for their host lock push-down.
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>
Acked-by: NJames Bottomley <James.Bottomley@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix I/O stalls with some 4-bay RAID enclosures which are based on
OXUF936QSE:
  - Onnto dataTale RSM4QO, old firmware (not anymore with current
    firmware),
  - inXtron Hydra Super-S LCM, old as well as current firmware
when used in RAID-5 mode, perhaps also in other RAID modes.

The stalls happen during heavy or moderate disk traffic in periods that
are a multiple of 5 minutes, roughly twice per hour.  They are caused
by the target responding too late to an ORB_Pointer register write:
The target responds after Split_Timeout, hence firewire-core cancels
the transaction, and firewire-sbp2 fails the SCSI request.  The SCSI
core retries the request, that fails again (and again), hence SCSI core
calls firewire-sbp2's abort handler (and even the Management_Agent
register write in the abort handler has the transaction timeout
problem).

During all that, the process which issued the I/O is stalled in I/O
wait state.

Meanwhile, the target actually acts on the first failed SCSI request:
It responds to the ORB_Pointer write later (seen in the kernel log as
"firewire_core: Unsolicited response") and also finishes the SCSI
request with proper status (seen in the kernel log as "firewire_sbp2:
status write for unknown orb").

So let's just ignore RCODE_CANCELLED in the transaction callback and
wait for the target to complete the ORB nevertheless.  This requires
a small modification is sbp2_cancel_orbs(); it now needs to call
orb->callback() regardless whether fw_cancel_transaction() found the
transaction unfinished or finished.

A different solution is to increase Split_Timeout on the local node.
(Tested: 2000ms timeout; maybe 1000ms or something like that works too.
200ms is insufficient.  Standard is 100ms.)  However, I rather not do
this because any software on any node could change the Split_Timeout to
something unsuitable.  Or such a large Split_Timeout may be undesirable
for other purposes.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

When an ORB was canceled (Command ORB i.e. SCSI request timed out, or
Management ORB timed out), or there was a send error in the initial
transaction, we missed to drop one of the ORB's references and thus
leaked memory.

Background:
In total, we hold 3 references to each Operation Request Block:
  - 1 during sbp2_scsi_queuecommand() or sbp2_send_management_orb()
    respectively,
  - 1 for the duration of the write transaction to the ORB_Pointer or
    Management_Agent register of the target,
  - 1 for as long as the ORB stays within the lu->orb_list, until
    the ORB is unlinked from the list and the orb->callback was
    executed.

The latter one of these 3 references is finished
  - normally by sbp2_status_write() when the target wrote status
    for a pending ORB,
  - or by sbp2_cancel_orbs() in case of an ORB time-out,
  - or by complete_transaction() in case of a send error.
Of them, the latter two lacked the kref_put.

Add the missing kref_put()s.  Add comments to the gets and puts of
references for transaction callbacks and ORB callbacks so that it is
easier to see what is supposed to happen.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

void (*fw_address_callback_t)(..., int speed, ...) is the speed that a
remote node chose to transmit a request to us.  In case of split
transactions, firewire-core will transmit the response at that speed.

Upper layer drivers on the other hand (firewire-net, -sbp2, firedtv, and
userspace drivers) cannot do anything useful with that speed datum,
except log it for debug purposes.  But data that is merely potentially
(not even actually) used for debug purposes does not belong into the API.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

In case of fw_card_bm_work()'s lock request, the present sizeof
expression is going to be wrong if somebody changes the fw_card's DMA
scratch buffer's size in the future.

In case of quadlet write requests, sizeof(u32) is just silly; it's 4.

In case of SBP-2 ORB pointer write requests, 8 is arguably quicker to
understand as the correct and only possible value than
sizeof(some_datum).
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The block layer calling convention is blk_queue_<limit name>.
blk_queue_max_sectors predates this practice, leading to some confusion.
Rename the function to appropriately reflect that its intended use is to
set max_hw_sectors.

Also introduce a temporary wrapper for backwards compability.  This can
be removed after the merge window is closed.
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Several config ROM related functions only peek at the ROM cache; mark
their arguments as const pointers.  Ditto fw_device.config_rom and
fw_unit.directory, as the memory behind them is meant to be write-once.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

A few stylistic changes to unify some code patterns in the subsystem:

  - The similar queue_delayed_work helpers fw_schedule_bm_work,
    schedule_iso_resource, and sbp2_queue_work now have the same call
    convention.
  - Two conditional calls of schedule_iso_resource are factored into
    another small helper.
  - An sbp2_target_get helper is added as counterpart to
    sbp2_target_put.

Object size of firewire-core is decreased a little bit, object size of
firewire-sbp2 remains unchanged.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The Unit_Characteristics entry of an SBP-2 unit directory is not
mandatory as far as I can tell.  If it is missing, we would probably
fail to log in into the target because firewire-sbp2 would not wait for
status after it sent the login request.

The fix moves the cleanup of tgt->mgt_orb_timeout into a place where it
is executed exactly once before login, rather than 0..n times depending
on the target's config ROM.  With targets with one or more
Unit_Characteristics entries, the result is the same as before.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The inquiry delay does more harm than good in tests on a recent kernel.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Per SBP-2 clause 5.3, a target shall store 8...32 bytes of status
information.  Trailing zeros after the first 8 bytes don't need to be
stored, they are implicit.  Fix the status write handler to clear all
unwritten status data.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

If a target writes invalid status (typically status of a command that
already timed out), firewire-sbp2 attempts to put away an ORB that
doesn't exist.  https://bugzilla.redhat.com/show_bug.cgi?id=519772Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Increase the command ORB data structure to transport up to 16 bytes long
CDBs (instead of 12 bytes), and tell the SCSI mid layer about it.  This
is notably necessary for READ CAPACITY(16) and friends, i.e. support of
large disks.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Retrieval of an fw_unit's parent is a common pattern in high-level code.
Wrap it up as device = fw_parent_device(unit).
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The source files of firewire-core, firewire-ohci, firewire-sbp2, i.e.
 "drivers/firewire/fw-*.c"
are renamed to
 "drivers/firewire/core-*.c",
 "drivers/firewire/ohci.c",
 "drivers/firewire/sbp2.c".

The old fw- prefix was redundant to the directory name.  The new core-
prefix distinguishes the files according to which driver they belong to.

This change comes a little late, but still before further firewire
drivers are added as anticipated RSN.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The three header files of firewire-core, i.e.
 "drivers/firewire/fw-device.h",
 "drivers/firewire/fw-topology.h",
 "drivers/firewire/fw-transaction.h",
are replaced by
 "drivers/firewire/core.h",
 "include/linux/firewire.h".

The latter includes everything which a firewire high-level driver (like
firewire-sbp2) needs besides linux/firewire-constants.h, while core.h
contains the rest which is needed by firewire-core itself and by low-
level drivers (card drivers) like firewire-ohci.

High-level drivers can now also reside outside of drivers/firewire
without having to add drivers/firewire to the header file search path in
makefiles.  At least the firedtv driver will be such a driver.

I also considered to spread the contents of core.h over several files,
one for each .c file where the respective implementation resides.  But
it turned out that most core .c files will end up including most of the
core .h files.  Also, the combined core.h isn't unreasonably big, and it
will lose more of its contents to linux/firewire.h anyway soon when more
firewire drivers are added.  (IP-over-1394, firedtv, and there are plans
for one or two more.)

Furthermore, fw-ohci.h is renamed to ohci.h.  The name of core.h and
ohci.h is chosen with regard to name changes of the .c files in a
follow-up change.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Include required headers which were only indirectly included.
Remove unused includes and an unused constant.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

That way, the new firedtv driver will be able to use a single ID table
in builds against ieee1394 core and/or against firewire core.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

type
    function_name(parameters);

is nice to look at but was not used consistently.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

According to https://bugs.launchpad.net/bugs/294391
  - 3rd generation iPods need the "fix capacity" workaround after all
    (apparently they crash after the last sector was accessed),
  - 2nd generation iPods need the "128 kB maximum request size"
    workaround.

Alas both iPod generations feature the same model ID in the config ROM,
hence we can only define a shared quirks list entry for them.  Luckily
the fix capacity workaround did not show a negative effect in Jarod's
tests with 2nd gen. iPod.

A side note:  Apple computers in target mode (or at least an x86 Mac
mini) don't have firmware_version and model_id, hence none of the iPod
quirks list entries is active for them.
Tested-by: NJarod Wilson <jarod@redhat.com>
Acked-by: NJarod Wilson <jarod@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Reported-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
who also provided a first version of the fix.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

1394-2008 clause 16.3.4.1 (1394b-2002 clause 16.3.1.1) defines tighter
limits than 1394-2008 clause 6.2.2.3 (1394a-2000 clause 6.2.2.3).

Our previously too large limit doesn't matter though if the controller
reports its max_receive correctly.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

What was I thinking when I added sbp2_set_generation()?  Its locking did
nothing (except for implicitly providing the necessary barrier between
node IDs update and generation update).
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Add another model ID of a broken firmware to prevent early I/O errors
by acesses at the end of the disk.  Reported at linux1394-user,
http://marc.info/?t=122670842900002Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

1: There is a small race between queue_delayed_work() and its
   corresponding kref_get().  Do the kref_get first, and _put it again
   if the queue_delayed_work() failed, so there is no chance of the
   kref going to zero while the work is scheduled.
2: An SBP2_LOGOUT_REQUEST could be sent out with a login_id full of
   garbage.  Initialize it to an invalid value so we can tell if we
   ever got a valid login_id.
3: The node ID and generation may have changed but the new values may
   not yet have been recorded in lu and tgt when the final logout is
   attempted.  Use the latest values from the device in
   sbp2_release_target().
Signed-off-by: NJay Fenlason <fenlason@redhat.com>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This optimizes firewire-sbp2's device probe for the case that the local
node and the SBP-2 node were discovered at the same time.  In this case,
fw-core's bus management work and fw-sbp2's login and SCSI probe work
are scheduled in parallel (in the globally shared workqueue and in
fw-sbp2's workqueue, respectively).  The bus reset from fw-core may then
disturb and extremely delay the login and SCSI probe because the latter
fails with several command timeouts and retries and has to be retried
from scratch.

We avoid this particular situation of sbp2_login() and fw_card_bm_work()
running in parallel by delaying the first sbp2_login() a little bit.

This is meant to be a short-term fix for
https://bugzilla.redhat.com/show_bug.cgi?id=466679.  In the long run,
the SCSI probe, i.e. fw-sbp2's call of __scsi_add_device(), should be
parallelized with sbp2_reconnect().

Problem reported and fix tested and confirmed by Alex Kanavin.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

queuecommand() looked at the remote and local node IDs before it read
the bus generation.  The corresponding race with sbp2_reconnect updating
these data was probably impossible to happen though because the current
code blocks the SCSI layer during reconnection.  However, better safe
than sorry, especially if someone later improves the code to not block
the SCSI layer.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

1. We don't need to round the SBP-2 segment size limit down to a
   multiple of 4 kB (0xffff -> 0xf000).  It is only necessary to
   ensure quadlet alignment (0xffff -> 0xfffc).

2. Use dma_set_max_seg_size() to tell the DMA mapping infrastructure
   and the block IO layer about the restriction.  This way we can
   remove the size checks and segment splitting in the queuecommand
   path.

   This assumes that no other code in the firewire stack uses
   dma_map_sg() with conflicting requirements.  It furthermore assumes
   that the controller device's platform actually allows us to set the
   segment size to our liking.  Assert the latter with a BUG_ON().

3. Also use blk_queue_max_segment_size() to tell the block IO layer
   about it.  It cannot know it because our scsi_add_host() does not
   point to the FireWire controller's device.

Thanks to Grant Grundler and FUJITA Tomonori for advice.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Share code between fw_send_request + wait_for_completion callers.
Signed-off-by: NJay Fenlason <fenlason@redhat.com>

Addendum:
Removes an unnecessary struct and an ununsed retry loop.
Calls it fw_run_transaction() instead of fw_send_request_sync().
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Acked-by: NKristian Høgsberg <krh@redhat.com>

Add per-device dma_mapping_ops support for CONFIG_X86_64 as POWER
architecture does:

This enables us to cleanly fix the Calgary IOMMU issue that some devices
are not behind the IOMMU (http://lkml.org/lkml/2008/5/8/423).

I think that per-device dma_mapping_ops support would be also helpful for
KVM people to support PCI passthrough but Andi thinks that this makes it
difficult to support the PCI passthrough (see the above thread).  So I
CC'ed this to KVM camp.  Comments are appreciated.

A pointer to dma_mapping_ops to struct dev_archdata is added.  If the
pointer is non NULL, DMA operations in asm/dma-mapping.h use it.  If it's
NULL, the system-wide dma_ops pointer is used as before.

If it's useful for KVM people, I plan to implement a mechanism to register
a hook called when a new pci (or dma capable) device is created (it works
with hot plugging).  It enables IOMMUs to set up an appropriate
dma_mapping_ops per device.

The major obstacle is that dma_mapping_error doesn't take a pointer to the
device unlike other DMA operations.  So x86 can't have dma_mapping_ops per
device.  Note all the POWER IOMMUs use the same dma_mapping_error function
so this is not a problem for POWER but x86 IOMMUs use different
dma_mapping_error functions.

The first patch adds the device argument to dma_mapping_error.  The patch
is trivial but large since it touches lots of drivers and dma-mapping.h in
all the architecture.

This patch:

dma_mapping_error() doesn't take a pointer to the device unlike other DMA
operations.  So we can't have dma_mapping_ops per device.

Note that POWER already has dma_mapping_ops per device but all the POWER
IOMMUs use the same dma_mapping_error function.  x86 IOMMUs use device
argument.

[akpm@linux-foundation.org: fix sge]
[akpm@linux-foundation.org: fix svc_rdma]
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix bnx2x]
[akpm@linux-foundation.org: fix s2io]
[akpm@linux-foundation.org: fix pasemi_mac]
[akpm@linux-foundation.org: fix sdhci]
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix sparc]
[akpm@linux-foundation.org: fix ibmvscsi]
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Muli Ben-Yehuda <muli@il.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Avi Kivity <avi@qumranet.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>