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This patch contains the following cleanups:
- #if 0 the following unused structs:
- fw-transaction.c:fw_low_memory_region
- fw-transaction.c:fw_private_region
- fw-transaction.c:fw_csr_region
- fw-transaction.c:fw_unit_space_region
- remove the following unused EXPORT_SYMBOL's:
- fw-card.c:fw_core_add_descriptor
- fw-card.c:fw_core_remove_descriptor
- fw-iso.c:fw_iso_context_create
- fw-iso.c:fw_iso_context_destroy
- fw-iso.c:fw_iso_context_start
- fw-iso.c:fw_iso_context_queue
- fw-iso.c:fw_iso_context_stop
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Fix: The fact that nodes had different gap counts would be overlooked
if the bus manager code would pick gap count 63 because of beta
repeaters or because of very large hop counts. In this case, the bus
manager code would miss that it actually has to send the PHY config
packet with gap count 63.
Related trivial changes: Use bool for an int used as bool, touch up
some comments.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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loop)
We now exit fw_send_phy_config /after/ the PHY config packet has been
transmitted, instead of before. A subsequent fw_core_initiate_bus_reset
will therefore not overlap with the transmission. This is meant to make
the send PHY config packet + reset bus routine more deterministic.
Fixes bus reset loop and eventual panic with
- VIA VT6307 + IOGEAR hub + Unibrain Fire-i camera
http://bugzilla.kernel.org/show_bug.cgi?id=10128
- JMicron card
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
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request_generation is internal to fw-ohci and unneeded in fw_card.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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for code efficiency.
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Trivial change to replace more meaningless (to the untrained eye) hex
values with defined CSR constants.
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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When a device changes its configuration ROM, it announces this with a
bus reset. firewire-core has to check which node initiated a bus reset
and whether any unit directories went away or were added on this node.
Tested with an IOI FWB-IDE01AB which has its link-on bit set if bus
power is available but does not respond to ROM read requests if self
power is off. This implements
- recognition of the units if self power is switched on after fw-core
gave up the initial attempt to read the config ROM,
- shutdown of the units when self power is switched off.
Also tested with a second PC running Linux/ieee1394. When the eth1394
driver is inserted and removed on that node, fw-core now notices the
addition and removal of the IPv4 unit on the ieee1394 node.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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read_bus_info_block() is repeatedly called by workqueue jobs.
These will step on each others toes eventually if there are multiple
workqueue threads, and we end up with corrupt config ROM images.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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and more)
Unlike the ohci1394 driver, fw-ohci uses the selfIDGeneration field of
bus reset packets to determine the generation of incoming requests as
per OHCI 1.1 clause 8.4.2.3. This is more precise --- provided that the
controller inserts the correct generation. Texas Instruments chips
often don't.
This prevented the transmission of response packets, which for example
broke AV/C transactions as used when communicating with miniDV cameras
and any other AV/C devices.
There is apparently no way to detect and adjust incorrect generations.
Therefore we ignore the generation of bus reset packets from TI chips
and use the generation of the self ID buffer instead. Alas this is
received at a slightly wrong time. In rare cases, this could cause us
to not respond to legitimate requests or to respond to expired requests.
(The latter is less likely because the bus reset packet AR event is
typically handled before the self ID complete event.)
Bug reported by Mladen Kuntner, who was extraordinarily patient while
dealing with the driver maintainers. Fix confirmed to be required and
effective for TSB82AA2 and a TSB43AB22 or TSB43AB22A.
https://bugzilla.redhat.com/show_bug.cgi?id=243081
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
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Extend the logging of "AR evt_bus_reset, link internal" to "AR
evt_bus_reset, generation ${selfIDGeneration}". That way we can check
whether this generation matches the one seen in self ID complete event
logging. See OHCI 1.1 clause 8.4.2.3.
Also extend logging of "firewire_ohci: * selfIDs, generation *" by
"local node ID ffc*" in self ID logging to make the local node in AT/AR
event logs more obvious.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
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Add a debug option to watch bus reset interrupt events. Half of this
patch is taken from Jarod Wilson's first version of the JMicron fix.
BusReset interrupts are only generated if the respective module
parameter flag was set before the controller is being initialized.
Else we keep this event masked to reduce IRQ load in normal operation
and to avoid potential problems with buggy chips.
Note, this is unlike the other IRQ events whose logging can be enabled
any time after chip initialization. This and the influence on what
interrupts the chip generates is why I added an extra flag for it.
Also, reorder the debug parameter flags according to their perceived
usefulness.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
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I finally tracked down the issues with this JMicron PCI-e card in my
possession to a failure to comply with section 7.2.3.2 of the OHCI 1.1
specification (thanks to Kristian for the pointer to illustrate that it
is indeed a flaw in this card, not the driver). The controller should
simply flush the packets we've appended to its AT queue if a bus reset
occurs before they've been transmitted and we'll try again, but
something goes wrong and the controller winds up hung.
However, we can avoid the problem by simply checking if the
IntEvent.busReset register had been set before we try appending to the
AT context. When busReset is set, the AT context is completely halted
until busReset is cleared, so there's no point in appending AT packets
until the register is cleared. So at_context_queue_packet() now checks
for busReset being set, and bails with an RCODE_GENERATION packet ack,
which results in us trying to append the packet again after recognizing
the fact there has been a bus reset, and clearing busReset.
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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While trying to debug this piece of crap JMicron PCI-e controller in my
possession, one thought was that perhaps I was encountering register access
failures. I'm not, but logging them would be good, so we can see if they
are a real problem we should be taking into account anywhere in the code.
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (added list contact)
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I've now witnessed multiple occasions where one of my controllers (a very
poorly working JMicron PCIe card) fails to get its registers properly set
up in ohci_enable(), apparently due to an occasionally very slow to
initiate SClk. The easy fix for this problem is to add a tiny while loop
to try again a time or three after initially enabling LPS before we
move on (or give up).
Of course, the card still isn't fully functional yet, but this gets it at
least one tiny step closer...
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Balance ohci_pmac_on and ohci_pmac_off if pci_driver.probe fails.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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and make another expression more readable.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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This adds debug printks for asynchronous transmission and reception and
for self ID reception. They can be enabled at module load time, and at
runtime via /sys/module/firewire_ohci/parameters/debug.
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Also added: Logging of interrupt event codes and of cancelled AT
packets.
The code now depends on a Kconfig variable. This makes it easier to
build firewire-ohci without the feature or to make it an option in the
future. The variable is currently hidden and always on.
This feature inflates firewire-ohci.ko by 7 kB = 27% on x86-64 and by
4 kB = 23% on i686.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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fw_core_handle_bus_reset() incorrectly relied on the assumption that
self_id_count > 0.
We check early in fw-ohci and discard the self ID complete event if
self_id_count == 0 because a valid event always has at least one self ID
packet in it (the one of the local node). Hence treat self_id_count ==
0 like any other kind of invalid self ID buffer.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
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Discard self ID buffer contents if
- the selfIDError flag is set,
- any of the self ID packets has bit errors.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
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Clean up shared code and variable names.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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The platform feature calls in the suspend method switched off cable
power, but the calls in the resume method did not switch it back on.
Add the necessary feature call to .resume. Also add the corresponding
call to .suspend to make .suspend's behavior explicitly the same on all
PMacs.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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This way firewire-ohci can be used for remote debugging like ohci1394.
Version with amendment from Fri, 11 Apr 2008 00:08:08 +0200.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Acked-by: Bernhard Kaindl <bk@suse.de>
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Try to write dual-phase retry protocol limits to BUSY_TIMEOUT register.
- The dual-phase retry protocol is optional to implement, and if not
supported, writes to the dual-phase portion of the register will be
ignored. We try to write the original 1394-1995 default here.
- In the case of devices that are also SBP-3-compliant, all writes are
ignored, as the register is read-only, but contains single-phase retry of
15, which is what we're trying to set for all SBP-2 device anyway, so this
write attempt is safe and yields more consistent behavior for all devices.
See section 8.3.2.3.5 of the 1394-1995 spec, section 6.2 of the SBP-2 spec,
and section 6.4 of the SBP-3 spec for further details.
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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The block/unblock logic is now sufficiently tested.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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orb came from kzalloc.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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How hard can it be to switch on one bit? :-)
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Write directly in big endian instead of byte-swapping after the fact.
This saves a few conversions, lets gcc use constant endianess
conversions where possible, and enables deeper endianess annotation.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Add wrappers for getting and putting a unit.
Remove some line breaks.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
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The reference count of the unit dropped too low in an error path in
sbp2_probe. Fixed by moving the _get further up.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
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The card->kref became obsolete since patch "firewire: fix crash in
automatic module unloading" added another counter of card users.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
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There's an ugly little memory leak in firewire-ohci's
ar_context_tasklet(), where we're not freeing up some of the memory we
use for each ar_buffer, due to a moving pointer. The problem has been
there for a while, but didn't get noticed until after converting the AR
routines over to use coherent DMA and I started running into I/O stall-
outs with the following message output repeatedly to the console:
PCI-DMA: Out of IOMMU space for 53248 bytes at device 0000:04:09.0
Plugging this leak is definitely necessary, but unfortunately, isn't the
entire answer to my problem, it only increases the amount of I/O that I
can do before hitting the problem. Still working on tracking down the
root cause..
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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This fixes a use-after-free bug in the handling of split transactions.
The AT DMA handler of the request was occasionally executed after the
AR DMA handler of the response. The AT DMA handler then accessed an
already freed packet.
Reported by Johannes Berg.
http://bugzilla.kernel.org/show_bug.cgi?id=9617
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Tested-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
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Shut up "may be used uninitialised in this function" warnings due to
PPC32's implementation of dma_alloc_coherent().
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Currently, we do nothing to guarantee we have a consistent DMA buffer for
asynchronous receive packets. Rather than doing several sync's following a
dma_map_single() to get consistent buffers, just switch to using
dma_alloc_coherent().
Resolves constant buffer failures on my own x86_64 laptop w/4GB of RAM and
likely to fix a number of other failures witnessed on x86_64 systems with
4GB of RAM or more.
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Fix I/O errors due to SYM13FW500's inability to handle larger request
sizes. Reported by Piergiorgio Sartor <piergiorgio.sartor@nexgo.de> in
https://bugzilla.redhat.com/show_bug.cgi?id=436879
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
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Remove some less necessary information, point out that video1394 and
dv1394 should be blacklisted along with ohci1394.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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If this ever happens to anybody, we want to have it in his log.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Per the SBP-2 specification, all SBP-2 target devices must have a BUSY_TIMEOUT
register. Per the 1394-1995 specification, the retry_limt portion of the
register should be set to 0x0 initially, and set on the target by a logged in
initiator (i.e., a Linux host w/firewire controller(s)).
Well, as it turns out, lots of devices these days have actually moved on to
starting to implement SBP-3 compliance, which says that retry_limit should
default to 0xf instead (yes, SBP-3 stomps directly on 1394-1995, oops).
Prior to this change, the firewire driver stack didn't touch retry_limit, and
any SBP-3 compliant device worked fine, while SBP-2 compliant ones were unable
to retransmit when the host returned an ack_busy_X, which resulted in stalled
out I/O, eventually causing the SCSI layer to give up and offline the device.
The simple fix is for us to set retry_limit to 0xf in the register for all
devices (which actually matches what the old ieee1394 stack did).
Prior to this change, a hard disk behind an SBP-2 Prolific PL-3507 bridge chip
would routinely encounter buffer I/O errors and wind up offlined by the SCSI
layer. With this change, I've encountered zero I/O failures moving tens of GB
of data around.
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Mostly copied from ohci1394.c. Necessary for some older Macs, e.g.
PowerBook G3 Pismo and early PowerBook G4 Titanium.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Copied from ohci1394.c. This code is necessary to prevent machine check
exceptions when reloading or resuming the driver.
Tested on a 1st generation PowerBook G4 Titanium, which also needs the
pci_probe() hunk.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
I was able to reproduce the system exception on resume with a 3rd-gen
Titanium PowerBook G4 667, and this patch does let the system resume
successfully now.
Not quite clear if there was possibly an updated version coming using
pci_enable_device() instead of the pair of pmac_call_feature() calls,
but either way, this is a definite must-have, at least for older ppc
macs -- my Aluminum PowerBook G4/1.67 suspends and resumes without this
patch just fine.
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Kills warnings from 'make C=1 CHECKFLAGS="-D__CHECK_ENDIAN__" modules':
drivers/firewire/fw-transaction.c:771:10: warning: incorrect type in assignment (different base types)
drivers/firewire/fw-transaction.c:771:10: expected unsigned int [unsigned] [usertype] <noident>
drivers/firewire/fw-transaction.c:771:10: got restricted unsigned int [usertype] <noident>
drivers/firewire/fw-transaction.h:93:10: warning: incorrect type in assignment (different base types)
drivers/firewire/fw-transaction.h:93:10: expected unsigned int [unsigned] [usertype] <noident>
drivers/firewire/fw-transaction.h:93:10: got restricted unsigned int [usertype] <noident>
drivers/firewire/fw-ohci.c:1490:8: warning: restricted degrades to integer
drivers/firewire/fw-ohci.c:1490:35: warning: restricted degrades to integer
drivers/firewire/fw-ohci.c:1516:5: warning: cast to restricted type
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
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The generation of incoming requests was filled in in wrong byte order on
machines with big endian CPU.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
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"modprobe firewire-ohci; sleep .1; modprobe -r firewire-ohci" used to
result in crashes like this:
BUG: unable to handle kernel paging request at ffffffff8807b455
IP: [<ffffffff8807b455>]
PGD 203067 PUD 207063 PMD 7c170067 PTE 0
Oops: 0010 [1] PREEMPT SMP
CPU 0
Modules linked in: i915 drm cpufreq_ondemand acpi_cpufreq freq_table applesmc input_polldev led_class coretemp hwmon eeprom snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss button thermal processor sg snd_hda_intel snd_pcm snd_timer snd snd_page_alloc sky2 i2c_i801 rtc [last unloaded: crc_itu_t]
Pid: 9, comm: events/0 Not tainted 2.6.25-rc2 #3
RIP: 0010:[<ffffffff8807b455>] [<ffffffff8807b455>]
RSP: 0018:ffff81007dcdde88 EFLAGS: 00010246
RAX: ffff81007dc95040 RBX: ffff81007dee5390 RCX: 0000000000005e13
RDX: 0000000000008c8b RSI: 0000000000000001 RDI: ffff81007dee5388
RBP: ffff81007dc5eb40 R08: 0000000000000002 R09: ffffffff8022d05c
R10: ffffffff8023b34c R11: ffffffff8041a353 R12: ffff81007dee5388
R13: ffffffff8807b455 R14: ffffffff80593bc0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffffffff8055a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: ffffffff8807b455 CR3: 0000000000201000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process events/0 (pid: 9, threadinfo ffff81007dcdc000, task ffff81007dc95040)
Stack: ffffffff8023b396 ffffffff88082524 0000000000000000 ffffffff8807d9ae
ffff81007dc5eb40 ffff81007dc9dce0 ffff81007dc5eb40 ffff81007dc5eb80
ffff81007dc9dce0 ffffffffffffffff ffffffff8023be87 0000000000000000
Call Trace:
[<ffffffff8023b396>] ? run_workqueue+0xdf/0x1df
[<ffffffff8023be87>] ? worker_thread+0xd8/0xe3
[<ffffffff8023e917>] ? autoremove_wake_function+0x0/0x2e
[<ffffffff8023bdaf>] ? worker_thread+0x0/0xe3
[<ffffffff8023e813>] ? kthread+0x47/0x74
[<ffffffff804198e0>] ? trace_hardirqs_on_thunk+0x35/0x3a
[<ffffffff8020c008>] ? child_rip+0xa/0x12
[<ffffffff8020b6e3>] ? restore_args+0x0/0x3d
[<ffffffff8023e68a>] ? kthreadd+0x14c/0x171
[<ffffffff8023e68a>] ? kthreadd+0x14c/0x171
[<ffffffff8023e7cc>] ? kthread+0x0/0x74
[<ffffffff8020bffe>] ? child_rip+0x0/0x12
Code: Bad RIP value.
RIP [<ffffffff8807b455>]
RSP <ffff81007dcdde88>
CR2: ffffffff8807b455
---[ end trace c7366c6657fe5bed ]---
Note that this crash happened _after_ firewire-core was unloaded. The
shared workqueue tried to run firewire-core's device initialization jobs
or similar jobs.
The fix makes sure that firewire-ohci and hence firewire-core is not
unloaded before all device shutdown jobs have been completed. This is
determined by the count of device initializations minus device releases.
Also skip useless retries in the node initialization job if the node is
to be shut down.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
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The bus management workqueue job was in danger to dereference NULL
pointers. Also, after having temporarily lifted card->lock, a few node
pointers and a device pointer may have become invalid.
Add NULL pointer checks and get the necessary references. Also, move
card->local_node out of fw_card_bm_work's sight during shutdown of the
card.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
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Patch "firewire: fw-sbp2: fix NULL pointer deref. in scsi_remove_device"
had the unintended effect that firewire-sbp2 could not be unloaded
anymore until all SBP-2 devices were unplugged.
We now fix the NULL pointer bug by reacquiring a reference to the sdev
instead of holding a reference to the sdev (and to the module) all the
time.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Tested-by: Jarod Wilson <jwilson@redhat.com>
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By supplying ioctl()s in the wrong order, a userspace client was able to
trigger NULL pointer dereferences. Furthermore, by calling
ioctl_create_iso_context more than once, new contexts could be created
without ever freeing the previously created contexts.
Thanks to Anders Blomdell for the report.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Fix a kernel bug when unplugging an SBP-2 device after having its
scsi_device already removed via the "delete" sysfs attribute.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Fix a kernel bug when running rescan-scsi-bus while a FireWire disk is
connected: http://bugzilla.kernel.org/show_bug.cgi?id=10008
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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While fw-sbp2 takes the necessary time to reconnect to a logical unit
after bus reset, the SCSI core keeps sending new commands. They are all
immediately completed with host busy status, and application clients or
filesystems will break quickly. The SCSI device might even be taken
offline: http://bugzilla.kernel.org/show_bug.cgi?id=9734
The only remedy seems to be to block the SCSI device until reconnect.
Alas the SCSI core has no useful API to block only one logical unit i.e.
the scsi_device, therefore we block the entire Scsi_Host. This
currently corresponds to an SBP-2 target. In case of targets with
multiple logical units, we need to satisfy the dependencies between
logical units by carefully tracking the blocking state of the target and
its units. We block all logical units of a target as soon as one of
them needs to be blocked, and keep them blocked until all of them are
ready to be unblocked.
Furthermore, as the history of the old sbp2 driver has shown, the
scsi_block_requests() API is a minefield with high potential of
deadlocks. We therefore take extra measures to keep logical units
unblocked during __scsi_add_device() and during shutdown.
This avoids I/O errors during reconnect in many but alas not in all
cases. There may still be errors after a re-login had to be performed.
Also, some bridges have been seen to cease fetching management ORBs if
I/O went on up until a bus reset. In these cases, all management ORBs
time out after mgt_orb_timeout. The old sbp2 driver is less vulnerable
or maybe not vulnerable to this, for as yet unknown reasons.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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