Scsi_remove_device() may go into uninterruptible sleep if blocked.
Therefore sbp2_remove() unblocks the Scsi_Host before the device is
requested to be removed.  But there could be another 1394 bus reset
after that which would block the host again.  The 1394 subsystem won't
call sbp2_update() concurrently to sbp2_remove(), which is why there is
no chance for sbp2_remove() to be unblocked by sbp2_update().

The fix is to tell sbp2's bus reset handler when a device is to be shut
down so that it skips scsi_block_requests() on that host.  As before,
any new commands after a reset without reconnect will be failed quickly
by sbp2scsi_queuecommand().

In the long term, means to go without scsi_block_requests() should be
found.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Remove unused includes.  Add missing includes, i.e. explicitly include
all used headers.  Sort includes alphabetically.  Replace one call to
signal_pending(current) to avoid to include headers just for this line.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

If the target signals a transport failure via status block, complete the
request with DID_BUSY to indicate to the SCSI subsystem that the command
may succeed when retried.

Also log diagnostic information if the status block shows a transport
related problem.  It may point to hardware faults.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

While sbp2_update() is doing its duties after a bus reset, another reset
could happen.  Don't accept new requests until the next undisturbed
sbp2_update() or until sbp2_remove().
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The scsi_host_template's eh_abort_handler and eh_device_reset_handler
are allowed to sleep.  Use this to run sbp2_agent_reset in the more
reliable mode which returns _after_ its write transaction was finished.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Fix for http://bugzilla.kernel.org/show_bug.cgi?id=6948

Because sbp2 writes to the target's fetch agent's registers from within
atomic context, it cannot sleep to guaranteedly get a free transaction
label.  This may repeatedly lead to "sbp2util_node_write_no_wait failed"
and consequently to SCSI command abortion after timeout.  A likely cause
is that many queue_command softirqs may occur before khpsbpkt (the
ieee1394 driver's thread which cleans up after finished transactions) is
woken up to recycle tlabels.

Sbp2 now schedules a workqueue job whenever sbp2_link_orb_command fails
in sbp2util_node_write_no_wait.  The job will reliably get a transaction
label because it can sleep.

We use the kernel-wide shared workqueue because it is unlikely that the
job itself actually needs to sleep.  In the improbable case that it has
to sleep, it doesn't need to sleep long since the standard transaction
timeout is 100ms.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Remove some code which is unneeded if CONFIG_PM=n.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

A deactivated macro, defined as "#define foo(bar)", will result in
silent corruption if somebody forgets a semicolon after a call to foo.
Replace it by "#define foo(bar) do {} while (0)" which will reveal any
respective syntax errors.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This patch adds support for the poll file operation to the video1394
driver.
Signed-off-by: NDavid Moore <dcm@acm.org>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This patch contains the scheduled removal of the force_inquiry_hack
module parameter.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This makes debugging with firescope easier.

Signed-off-by: Andi Kleen <ak@suse.de> (original patch)

Update:
 - no need for #ifdef MODULE
 - add comment in ieee1394_core, more verbose comment in ohci1394

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (update)

The waitqueue API is used to replace a custom wait mechanism.  Only one
global waitqueue (instead of per-device waitqueues or completions) is
added because there is usually just one waiter.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

 - Add checks for the (very unlikely) cases that the target writes too
   little or too much status data or writes unsolicited status.
 - Indicate that these and similar conditions are unlikely().
 - Check the 'resp' and 'sbp_status' fields for possible failure status.
 - Slightly optimize access macros for the status block bitfields.
 - Unify a few related log messages.

TODO:  Check if 'src'==1, then withhold the respective ORB from reuse
until status for any subsequent ORB was received.  This is an old bug
whose fix requires more complex command queue handling.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Sbp2's copy of the status fifo was cleared when management ORBs or new
command ORBs were prepared.  The latter had potential for a race
condition if the block layer's soft IRQ and the 1394 LLD's interrupt
handler ran on different CPUs.  It would also yield wrong status if a
command was completed with non-zero completion status before other
commands that had zero completion status, and no new command was
enqueued in the meantime.

Now, the status buffer is cleared right before it is written.  Thus it
ends up in the following simpler and safer access pattern:
 - sbp2_alloc_device: allocates and implicitly clears once,
 - sbp2_handle_status_write: clears, writes, and reads,
 - sbp2_query_logins, sbp2_login_device, sbp2_reconnect_device: read.
The latter three do not race with sbp2_handle_status_write because of
how the protocol works.

As a tiny optimization, the first two quadlets of the status never need
to be cleared.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Only the driver writes ORBs, the device just reads them.  Therefore
PCI_DMA_BIDIRECTIONAL can be replaced by PCI_DMA_TODEVICE which may be
cheaper on some architectures.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Since sbp2 is at the moment unable to do anything with the return value
of sbp2_link_orb_command, just discard it.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

The sbp2 initiator has two ways to tell a target's fetch agent about new
command ORBs:
 - Write the ORB's address to the ORB_POINTER register.  This must not
   be done while the fetch agent is active.
 - Put the ORB's address into the previously submitted ORB's next_ORB
   field and write to the DOORBELL register.  This may be done while the
   fetch agent is active or suspended.  It must not be done while the
   fetch agent is in reset state.
Sbp2 has a last_orb pointer which indicates in what way a new command
should be announced.  That pointer is concurrently accessed at various
occasions.  Furthermore, initiator and target are accessing the next_ORB
field of ORBs concurrently and asynchronously.

This patch does:
 - Protect all initiator accesses to last_orb by sbp2_command_orb_lock.
 - Add pci_dma_sync_single_for_device before a previously submitted
   ORB's next_ORB field is overwritten.
 - Insert a memory barrier between when next_ORB_lo and next_ORB_hi are
   overwritten.  Next_ORB_hi must not be updated before next_ORB_lo.
 - Remove the rather unspecific and now superfluous qualifier "volatile"
   from the next_ORB fields.
 - Add comments on how last_orb is connected with what is known about
   the target's fetch agent's state.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

These includes in ieee1394_core and eth1394 are obsolete.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

This patch reduces the size of struct hpsb_host and also removes
semaphores from ieee1394_transactions.c.  On i386, struct hpsb_host
shrinks from 10656 bytes to 6688 bytes.  This is accomplished by
 - using a single wait_queue for hpsb_get_tlabel instead of many
   instances of semaphores,
 - using a single lock to serialize access to all tlabel pools (the
   protected code regions are small, i.e. lock contention very low),
 - omitting the sysfs attribute tlabels_allocations.

Drawback:  In the rare case that a process needs to sleep because all
transaction labels for the node are temporarily exhausted, it is also
woken up if a tlabel for a different node became free, checks for an
available tlabel, and is put to sleep again.  The check is not costly
and the situation occurs extremely rarely.  (Tlabels are typically
only exhausted if there was no context switch to the khpsbpkt thread
which recycles tlables.)  Therefore the benefit of reduced tpool size
outweighs this drawback.

The sysfs attributes tlabels_free and tlabels_mask are not compiled
anymore unless CONFIG_IEEE1394_VERBOSEDEBUG is set.

The by far biggest member of struct hpsb_host, the struct csr_control
csr (5272 bytes on i386), is now placed at the end of struct hpsb_host.

Note, hpsb_get_tlabel calls the macro wait_event_interruptible with a
condition argument which has a side effect (allocation of a tlabel and
manipulation of the packet).  This side effect happens only if the
condition is true.  The patch relies on wait_event_interruptible not
evaluating the condition again after it became true.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

Recently a patch was added for preliminary suspend/resume handling on
!PPC_PMAC.  However, this broke both suspend and firewire on powerpc
because it saves the pci state after the device has already been disabled.

This moves the save state to before the pmac specific code.
Signed-off-by: NDanny Tholen <obiwan@mailmij.org>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ben Collins <bcollins@ubuntu.com>
Cc: Jody McIntyre <scjody@modernduck.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

At least Maxtor OneTouch III require a "start stop unit" command after auto
spin-down before the next access can proceed.  This patch activates the
responsible code in scsi_mod for all Maxtor SBP-2 disks.
https://bugzilla.novell.com/show_bug.cgi?id=183011

Maybe that should be done for all SBP-2 disks, but better be cautious.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Jody McIntyre <scjody@modernduck.com>
Cc: Ben Collins <bcollins@ubuntu.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

ieee1394 reuses the skb infrastructure of the networking code, and uses two
skb-head queues: ->pending_packet_queue and hpsbpkt_queue.  The latter is used
in the usual fashion: processed from a kernel thread.  The other one,
->pending_packet_queue is also processed from hardirq context (f.e.  in
hpsb_bus_reset()), which is not what the networking code usually does (which
completes from softirq or process context).  This locking assymetry can be
totally correct if done carefully, but it can also be dangerous if networking
helper functions are reused, which could assume traditional networking use.

It would probably be more robust to push this completion into a workqueue -
but technically the code can be 100% correct, and lockdep has to be taught
about it.  The solution is to split the ->pending_packet_queue skb-head->lock
class from the networking lock-class by using a private lock-validator key.

Has no effect on non-lockdep kernels.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Jody McIntyre <scjody@modernduck.com>
Cc: Ben Collins <bcollins@debian.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

There was stuff between the comment and the function.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

Another trivial sem2mutex conversion.

Side note:  nodemgr_serialize's purpose, when introduced in linux1394's
revision 529 in July 2002, was to protect several data structures which
are now largely handled by or together with Linux' driver core and are
now protected by the LDM's own mechanisms.  It may very well be possible
to remove this mutex now.  But fully parallelized node scanning is on
our long-term TODO list anyway; the mutex will certainly go away then.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

Convert nodemgr's host thread from kernel_thread to kthread and its
sleep/restart mechanism from a counting semaphore to a schedule()/
wake_up_process() scheme.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

Nodemgr's ignore_drivers variable is exposed as a module load parameter
(therefore also as a sysfs attribute below /sys/module) and additionally
as an attribute below /sys/bus/ieee1394.  Since the latter is writable,
make the former writable too.

Note, the bus's attribute ignore_drivers is only relevant to newly added
units, not to present or suspended or resuming units.  Those have their
own attribute ignore_driver.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

nodemgr.c::fw_set_rescan() is used to re-run the driver core over
nodemgr's representation of unit directories in order to initiate
protocol driver probes.  It is initiated via write access to one of
nodemgr's sysfs attributes.  The purpose is to attach drivers to
units after switching a unit's ignore_driver attribute from 1 to 0.

It is not really necessary to fork a kernel_thread for this job.  The
call to kernel_thread() can be eliminated to avoid the deprecated API
and to simplify the code a bit.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

An already existing wait queue replaces raw1394's complete_sem which was
maintained in parallel to the wait queue.  The role of the semaphore's
counter is taken over by a direct check of what was really counted:  The
presence of items in the list of completed requests.

Notes:

 - raw1394_release() sleeps uninterruptibly until all requests were
   completed.  This is the same behaviour as before the patch.

 - The macros wait_event and wait_event_interruptible are called with a
   condition argument which has a side effect, i.e. manipulation of the
   requests list.  This side effect happens only if the condition is
   true.  The patch relies on the fact that wait_event[_interruptible]
   does not evaluate the condition again after it became true.

 - The diffstat looks unfavorable with respect to added lines of code.
   However 19 of them are comments, and some are due to separation of
   existing code blocks into two small helper functions.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (not runtime-tested)
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

hpsb_update_config_rom() is defined in csr.c, not hosts.c.
hpsb_get_config_rom() does not exist.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

Remove unnecessary includes, add missing includes.
Use forward type declarations for some structs.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

Adjust tabulators, line wraps, empty lines, and comment style.
Update comments in ieee1394_transactions.h and highlevel.h.
Fix typo in comment in csr.h.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

The last loop in ieee1394 core's speed calculation is not required
unless ieee1394.h::IEEE1394_SPEED_MAX is changed from its current value
of 3.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

This variant of calculate_expire() is more correct and easier to read.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

At least Maxtor OneTouch III require a "start stop unit" command after
auto spin-down before the next access can proceed.  This patch activates
the responsible code in scsi_mod for all Maxtor SBP-2 disks.
https://bugzilla.novell.com/show_bug.cgi?id=183011

Maybe that should be done for all SBP-2 disks, but better be cautious.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>

If ieee1394.h::IEEE1394_SPEED_MAX is bigger than the actual speed of an
1394b host adapter and the speed to another 1394b node was probed, a
bigger speed than actually used was kept in host->speed[n].  The only
resulting problem so far was sbp2 displaying bogus values in the syslog,
e.g. S3200 for actual S800 connections if IEEE1394_SPEED_MAX was S3200.
But other high-level drivers which access this field could get into more
trouble.  (Eth1394 is the only other in-tree driver which does so.  It
seems it is not affected.)

Nodemgr now clips this value according to the host adapter's link speed.

A pointer expression in nodemgr_check_speed is also changed for clarity.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: NBen Collins <bcollins@ubuntu.com>