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The only user of the i_cindex element in the inode structure is used
is by the firewire drivers. As part of an attempt to slim down the
inode structure to save memory --- since a typical Linux system will
have hundreds of thousands if not millions of inodes cached, a
reduction in the size inode has high leverage.
The firewire driver does not need i_cindex in any fast path, so it's
simple enough to calculate when it is needed, instead of wasting space
in the inode structure.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: krh@redhat.com
Cc: stefanr@s5r6.in-berlin.de
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Replace all DMA_32BIT_MASK macro with DMA_BIT_MASK(32)
Signed-off-by: Yang Hongyang<yanghy@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6: (53 commits)
DVB: firedtv: FireDTV S2 problems with tuning solved
DVB: firedtv: fix printk format mismatch
ieee1394: constify device ID tables
ieee1394: raw1394: add sparse annotations to raw1394_compat_write
ieee1394: Storage class should be before const qualifier
ieee1394: sbp2: follow up on "ieee1394: inherit ud vendor_id from node vendor_id"
firewire: core: optimize propagation of BROADCAST_CHANNEL
firewire: core: simplify broadcast channel allocation
firewire: core: increase bus manager grace period
firewire: core: drop unused call parameters of close_transaction
firewire: cdev: add closure to async stream ioctl
firewire: cdev: simplify FW_CDEV_IOC_SEND_REQUEST return value
firewire: cdev: fix race of ioctl_send_request with bus reset
firewire: cdev: secure add_descriptor ioctl
firewire: cdev: amendment to "add ioctl to query maximum transmission speed"
firewire: broadcast channel support
firewire: implement asynchronous stream transmission
firewire: core: normalize a function argument name
firewire: normalize a variable name
firewire: core: remove condition which is always false
...
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Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Eliminate the following warnings in raw1394_compat_write()'s error
return path, seen on x86-64 with CONFIG_COMPAT=y:
drivers/ieee1394/raw1394.c:381:17: warning: incorrect type in return expression (different address spaces)
drivers/ieee1394/raw1394.c:381:17: expected char const [noderef] <asn:1>*
drivers/ieee1394/raw1394.c:381:17: got void *
drivers/ieee1394/raw1394.c:2252:14: warning: incorrect type in argument 1 (different address spaces)
drivers/ieee1394/raw1394.c:2252:14: expected void const *ptr
drivers/ieee1394/raw1394.c:2252:14: got char const [noderef] <asn:1>*[assigned] buffer
drivers/ieee1394/raw1394.c:2253:19: warning: incorrect type in argument 1 (different address spaces)
drivers/ieee1394/raw1394.c:2253:19: expected void const *ptr
drivers/ieee1394/raw1394.c:2253:19: got char const [noderef] <asn:1>*[assigned] buffer
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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The C99 specification states in section 6.11.5:
The placement of a storage-class specifier other than at the beginning
of the declaration specifiers in a declaration is an obsolescent
feature.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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vendor_id"
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Most fasync implementations do something like:
return fasync_helper(...);
But fasync_helper() will return a positive value at times - a feature used
in at least one place. Thus, a number of other drivers do:
err = fasync_helper(...);
if (err < 0)
return err;
return 0;
In the interests of consistency and more concise code, it makes sense to
map positive return values onto zero where ->fasync() is called.
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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It needs to happen before any firewire driver actually registers itself,
and that was previously handled by having the Makefile list the core
ieee1394 files before the drivers.
But now there are firewire drivers in drivers/media, and the Makefile
games aren't enough. So just make ieee1394_init happen earlier in the
init sequence, the way all other bus layers already do.
Reported-and-tested-by: Ingo Molnar <mingo@elte.hu>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Henrik Kurelid <henrik@kurelid.se>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Ben Backx <ben@bbackx.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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hpsb_read, hpsb_write, hpsb_lock are sleeping functions which nobody is
in danger to use in atomic context. Besides, in_interrupt does not
cover all types of atomic context.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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While Module_Vendor_ID in the configuration ROM's root directory is
mandatory, there often aren't vendor IDs in unit directories. This
affects the new firedtv driver which is meant to be auto-loaded and
matched only for vendor-specific devices.
We now always copy ne->vendor_id into ud->vendor_id before we scan a
unit directory (and fill in a possibly present vendor ID from there).
This way, the root directory's vendor ID is used as fallback in the
"uevent" environment for modprobe'ing per module alias when a node was
plugged in, and in the driver match routine when protocol drivers are
bound to unit directories. It will however not be used as sysfs
attribute of a unit directory device.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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These will be used by the firedtv driver. Like hpsb_node_write() they
are much better APIs for high-level drivers than hpsb_write() and its
siblings --- easier to use correctly and also terser.
Unlike hspb_node_write(), the two new functions will only be used by
one call site. Hence make them static inline instead of exported
symbols.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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A compiler barrier (explicit on the read side, implicit on the write
side) is not quite enough for what has to be accomplished here. Use
hardware memory barriers on systems which need them.
(Of course a full fix of generation handling would require much more
than this. The ieee1394 core's bus generation counter had to be tied to
the controller's bus generation counter; cf. Kristian's stack. It's
just that I have other current business with the code around these
barrier()s, so why not do at least this small fix.)
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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input
Combination of the following changes:
Tue, 26 Aug 2008 00:17:30 +0200 (CEST)
firedtv: fix remote control input
and update the scancode-to-keycode mapping to a current model. Per
default, various media key keycodes are emitted which closely match what
is printed on the remote. Userland can modify the mapping by means of
evdev ioctls. (Not tested.)
The old scancode-to-keycode mapping is left in the driver but cannot be
modified by ioctls. This preserves status quo for old remotes.
Tue, 26 Aug 2008 00:11:28 +0200 (CEST)
firedtv: replace tasklet by workqueue job
Non-atomic context is a lot nicer to work with.
Sun, 24 Aug 2008 23:30:00 +0200 (CEST)
firedtv: move some code back to ieee1394 core
Partially reverts "ieee1394: remove unused code" of Linux 2.6.25.
Sun, 24 Aug 2008 23:29:30 +0200 (CEST)
firedtv: replace semaphore by mutex
firesat->avc_sem and ->demux_sem have been used exactly like a mutex.
The only exception is the schedule_remotecontrol tasklet which did a
down_trylock in atomic context. This is not possible with
mutex_trylock; however the whole remote control related code is
non-functional anyway at the moment. This should be fixed eventually,
probably by turning the tasklet into a worqueue job.
Convert everything else from semaphore to mutex.
Also rewrite a few of the affected functions to unlock the mutex at a
single exit point, instead of in several branches.
Sun, 24 Aug 2008 23:28:45 +0200 (CEST)
firedtv: some header cleanups
Unify #ifndef/#define/#endif guards against multiple inclusion.
Drop extern keyword from function declarations.
Remove #include's into header files where struct declarations suffice.
Remove unused ohci1394 interface and related unused ieee1394 interfaces.
Add a few missing #include's and remove a few apparently obsolete ones.
Sort them alphabetically.
Sun, 24 Aug 2008 23:27:45 +0200 (CEST)
firedtv: nicer registration message and some initialization fixes
Print the correct name in dvb_register_adapter().
While we are at it, replace two switch cascades by one for loop, remove
a superfluous member of struct firesat and of two unused arguments of
AVCIdentifySubunit(), and fix bogus kfree's in firesat_dvbdev_init().
Tue, 26 Aug 2008 14:24:17 +0200 (CEST)
firesat: rename to firedtv
Suggested by Andreas Monitzer. Besides DVB-S/-S2 receivers, the driver
also supports DVB-C and DVB-T receivers, hence the previous project name
is too narrow now.
Not yet done: Rename source directory, files, types, variables...
Sun, 24 Aug 2008 23:26:23 +0200 (CEST)
firesat: add missing copyright notes
Reported by Andreas Monitzer and Christian Dolzer.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6:
ieee1394: dv1394: move deprecation message from module init to file open
firewire: core: Remove card from list of cards when enable fails
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On many Linux installations, the dv1394 driver will be auto-loaded
whenever an AV/C device (e.g. camcorder or audio device) is plugged in.
An irritating message would then appear in the kernel log.
Defer this message to until a dv1394 character device file is actually
used by a program. Also include the program name in the message and
update the message slightly.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6:
ieee1394: sbp2: add workarounds for 2nd and 3rd generation iPods
firewire: sbp2: add workarounds for 2nd and 3rd generation iPods
firewire: sbp2: fix DMA mapping leak on the failure path
firewire: sbp2: define some magic numbers as macros
firewire: sbp2: fix payload limit at S1600 and S3200
ieee1394: sbp2: don't assume zero model_id or firmware_revision if there is none
ieee1394: sbp2: fix payload limit at S1600 and S3200
ieee1394: sbp2: update a help string
ieee1394: support for speeds greater than S800
firewire: core: optimize card shutdown
ieee1394: ohci1394: increase AT req. retries, fix ack_busy_X from Panasonic camcorders and others
firewire: ohci: increase AT req. retries, fix ack_busy_X from Panasonic camcorders and others
firewire: ohci: change "context_stop: still active" log message
firewire: keep highlevel drivers attached during brief connection loss
firewire: unnecessary BM delay after generation rollover
firewire: insist on successive self ID complete events
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as per https://bugs.launchpad.net/bugs/294391. These got one sample of
each iPod generation going. However there still occurred I/O stalls
with the 3rd generation iPod which remain undiagnosed at the time of
this writing.
Acked-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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This makes sbp2 behave more like firewire-sbp2 which reports 0xff000000
as immediate value if there are no unit directory entries for model_id
or firmware_revision.
It does not reduce matches with the currently existing quirks table; the
only zero entry there is for a device which actually does have a zero
model_id. It only changes how model_id and firmware_revision are logged
if they are missing.
Other functionally unrelated changes: The model_id member of quirks
list entries is renamed to model; the value (but not the effect) of
SBP2_ROM_VALUE_WILDCARD is changed. Now this part of the source is
identical with firewire-sbp2 for easier maintenance.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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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: 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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The hard-wired configuration of the top speed (until now S800) was
unnecessary, remove it.
If the local link layer controller supports S1600 or S3200, we now
assume this speed for all present 1394b PHYs (except if they are
behind 1394a repeaters) until nodemgr figured out the actual speed
while fetching the config ROM.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Signed-off-by: Jean Delvare <khali@linux-fr.org>
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camcorders and others
Camcorders have a tendency to fail read requests to their config ROM and
write request to their FCP command register with ack_busy_X. This has
become a problem with newer kernels and especially Panasonic camcorders,
causing AV/C in dvgrab and kino to fail. Dvgrab for example frequently
logs "send oops"; kino reports loss of AV/C control. I suspect that
lower CPU scheduling latencies in newer kernels made this issue more
prominent now.
According to
https://sourceforge.net/tracker/?func=detail&atid=114103&aid=2492640&group_id=14103
this can be fixed by configuring the FireWire controller for more
hardware retries for request transmission; these retries are evidently
more successful than libavc1394's own retry loop (typically 3 tries on
top of hardware retries).
Presumably the same issue has been reported at
https://bugzilla.redhat.com/show_bug.cgi?id=449252 and
https://bugzilla.redhat.com/show_bug.cgi?id=477279 .
Tested-by: Mathias Beilstein
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6
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Use the network_device_stats field in network_device.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Last_rx is now done if needed inside bonding.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Convert to net_device_ops.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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After annotating the frame structs, this was left:
drivers/ieee1394/dv1394.c:2113:23: warning: invalid assignment: |=
drivers/ieee1394/dv1394.c:2113:23: left side has type restricted __le32
drivers/ieee1394/dv1394.c:2113:23: right side has type int
drivers/ieee1394/dv1394.c:2121:24: warning: invalid assignment: &=
drivers/ieee1394/dv1394.c:2121:24: left side has type restricted __le32
drivers/ieee1394/dv1394.c:2121:24: right side has type int
drivers/ieee1394/dv1394.c:2123:24: warning: invalid assignment: |=
drivers/ieee1394/dv1394.c:2123:24: left side has type restricted __le32
drivers/ieee1394/dv1394.c:2123:24: right side has type int
Which looks like a real bug on a big-endian arch as it would set/clear
the wrong bit.
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Bill Fink writes:
I finally got a chance to test the patch on my kernel, and live DV
viewing using xine still worked fine. Although I admit to being
mystified how it works both before and after the patch, since the
cpu_to_le32() calls that were added should result in byte swapping on
PPC that wasn't being done before. I guess that either the code paths
involved aren't actually being triggered by my xine DV viewing, or
there's some fortuitous palindromic setting of bits.
Tested-by: Bill Fink <billfink@mindspring.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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No Functional changes.
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Mostly annotations of ether_type as a be16.
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Two access functions get_max_rom and set_hw_config_rom are
changed to take __be32 as well. Only bus_info_data was
ever passed in so this is OK. All other uses of bus_info_data
treated it as a be32 value already.
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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bus_info_block was treated as a be32 everywhere, annotate
as such. Removes plenty of sparse warnings.
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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It is already known that buggy firmwares exist which report a bogus
link_spd in their config ROM bus info block. We now got the first
report of a bogus max_rom too (Freecom FireWire Hard Drive 1TB,
http://bugzilla.kernel.org/show_bug.cgi?id=12206).
I suspect other OSs only use quadlet reads to fetch the config ROM,
otherwise the firmware authors would have noticed their mistake.
Hence limit ieee1394's config ROM fetching routine to quadlets as the
safe minimum regardless of what the bus info block says.
This will potentially slow the bus reset handling by nodemgr somewhat
down. But most existing devices support only quadlet reads anyway,
hence there will often be no actual difference to before this change.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Move the definition out of nodemgr.h and use it in csr.c/pcilynx.c
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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and replace busy-wait by msleep.
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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On my HP 2510p I get the following in dmesg during near the end of most
resumes from suspend to RAM:
irq 19: nobody cared (try booting with the "irqpoll" option)
Pid: 0, comm: swapper Not tainted 2.6.28-rc7 #67
Call Trace:
<IRQ> [<ffffffffa00ee9e1>] ? ohci_irq_handler+0x60/0x7e9 [ohci1394]
[<ffffffff8026aa4d>] __report_bad_irq+0x38/0x87
[<ffffffff8026abaa>] note_interrupt+0x10e/0x174
[<ffffffff8026b262>] handle_fasteoi_irq+0xa7/0xd1
[<ffffffff8020eb87>] do_IRQ+0x73/0xe4
[<ffffffff8020c626>] ret_from_intr+0x0/0xa
<EOI> [<ffffffffa0012606>] ? acpi_idle_enter_bm+0x26b/0x2b2 [processor]
[<ffffffffa00125fc>] ? acpi_idle_enter_bm+0x261/0x2b2 [processor]
[<ffffffff8024f30f>] ? notifier_call_chain+0x33/0x5b
[<ffffffff803b9c64>] ? cpuidle_idle_call+0x8c/0xc4
[<ffffffff8020b312>] ? cpu_idle+0x4a/0x9a
[<ffffffff8042c5c8>] ? rest_init+0x5c/0x5e
handlers:
[<ffffffffa00ee981>] (ohci_irq_handler+0x0/0x7e9 [ohci1394])
Disabling IRQ #19
There also seems to be an interrupt storm during suspend/resume when this
happens:
19: 99968 33 IO-APIC-fasteoi ohci1394
This patch gets rid of both issues and makes the resume as a whole
significantly faster.
Signed-off-by: Frans Pop <elendil@planet.nl>
As was pointed out in http://lkml.org/lkml/2008/12/6/127, this does not
fix the cause of the interrupt storm. However, since the source of the
interrupts could not be determined yet, we make the system at least more
usable with this change.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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These are never modified.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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All callers of hpsb_register_addrspace() can sleep.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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According to http://bugzilla.kernel.org/show_bug.cgi?id=12206, Freecom
FireWire Hard Drive 1TB reports max_rom=2 but returns garbage if block
read requests are used to read the config ROM. Force max_rom=0 to limit
them to quadlet read requests.
Reported-by: Christian Mueller <cm1@mumac.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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The firewire nodemanager function "nodemgr_host_thread" contains a loop
that calls try_to_freeze near the top of the loop, but then delays for
up to 3.25 seconds (plus time to do work) before getting back to the top
of the loop. When starting a cycle post-boot, this doesn't seem to bite,
but it is causing a noticeable delay at boot time, when freezing
processes prior to starting to read the image.
The following patch adds invocation of try_to_freeze to the subloops
that are used in the body of this function. With these additions, the
time to freeze when starting to resume at boot time is virtually zero.
I'm no expert on firewire, and so don't know that we shouldn't check
the return value and jump back to the top of the loop or such like after
being frozen, but I submit it for your consideration.
Signed-off-by: Nigel Cunningham <nigel@tuxonice.net>
The delay until nodemgr freezes was up to 0.25s (plus time for node
probes) in Linux 2.6.27 and older and up to 3.25s (plus ~) since Linux
2.6.28-rc1, hence much more noticeable.
try_to_freeze() without any jump is correct. The surrounding code in
the respective loops will catch whether another bus reset happens during
the freeze and handle it.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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An intermediate transition from _RUNNING to _IN_SHUTDOWN could have been
missed by the former code.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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If there is more than one FireWire controller present, dummy_zero_addr
and dummy_max_addr were added multiple times to different lists, thus
corrupting the lists. Fix this by allocating them dynamically per host
instead of just once globally.
(Perhaps a better address space allocation algorithm could rid us of the
two dummy address spaces.)
Fixes http://bugzilla.kernel.org/show_bug.cgi?id=10129 .
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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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=122670842900002
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6:
ieee1394: dv1394: fix possible deadlock in multithreaded clients
ieee1394: raw1394: fix possible deadlock in multithreaded clients
ieee1394: struct device - replace bus_id with dev_name(), dev_set_name()
firewire: struct device - replace bus_id with dev_name(), dev_set_name()
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As it is, all instances of ->release() for files that have ->fasync()
need to remember to evict file from fasync lists; forgetting that
creates a hole and we actually have a bunch that *does* forget.
So let's keep our lives simple - let __fput() check FASYNC in
file->f_flags and call ->fasync() there if it's been set. And lose that
crap in ->release() instances - leaving it there is still valid, but we
don't have to bother anymore.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Fix a possible though highly unlikely deadlock:
Thread A: Thread B:
- acquire mmap_sem - dv1394_ioctl/read/write()
- dv1394_mmap() - acquire video->mtx
- acquire video->mtx - copy_to/from_user(), possible page fault:
acquire mmap_sem
The simplest fix is to use mutex_trylock() instead of mutex_lock() in
dv1394_mmap(). This changes the behavior under contention in a way
which is visible to userspace clients. However, my guess is that no
clients exist which use mmap vs. ioctl/read/write on the dv1394
character device file interface in concurrent threads.
Reported-by: Johannes Weiner <hannes@saeurebad.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Regression in 2.6.28-rc1: When I added the new state_mutex which
prevents corruption of raw1394's internal state when accessed by
multithreaded client applications, the following possible though
highly unlikely deadlock slipped in:
Thread A: Thread B:
- acquire mmap_sem - raw1394_write() or raw1394_ioctl()
- raw1394_mmap() - acquire state_mutex
- acquire state_mutex - copy_to/from_user(), possible page fault:
acquire mmap_sem
The simplest fix is to use mutex_trylock() instead of mutex_lock() in
raw1394_mmap(). This changes the behavior under contention in a way
which is visible to userspace clients. However, since multithreaded
access was entirely buggy before state_mutex was added and libraw1394's
documentation advised application programmers to use a handle only in a
single thread, this change in behaviour should not be an issue in
practice at all.
Since we have to use mutex_trylock() in raw1394_mmap() regardless
whether /dev/raw1394 was opened with O_NONBLOCK or not, we now use
mutex_trylock() unconditionally everywhere for state_mutex, just to have
consistent behavior.
Reported-by: Johannes Weiner <hannes@saeurebad.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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