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__bio_for_each_segment() iterates bvecs from the specified index
instead of bio->bv_idx. Currently, the only usage is to walk all the
bvecs after the bio has been advanced by specifying 0 index.
For immutable bvecs, we need to split these apart;
bio_for_each_segment() is going to have a different implementation.
This will also help document the intent of code that's using it -
bio_for_each_segment_all() is only legal to use for code that owns the
bio.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Neil Brown <neilb@suse.de>
CC: Boaz Harrosh <bharrosh@panasas.com>
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A bunch of what __blk_queue_bounce() was doing was problematic for the
immutable bvec work; this cleans that up and the code is quite a bit
smaller, too.
The __bio_for_each_segment() in copy_to_high_bio_irq() was changed
because that one's looping over the original bio, not the bounce bio -
a later patch renames __bio_for_each_segment() ->
bio_for_each_segment_all(), and documents that
bio_for_each_segment_all() is only for code that owns the bio.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
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This doesn't really delete any code _yet_, but once immutable bvecs are
done we can just delete the rest of the code in that loop.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
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In the short term this'll help with code auditing, and if this code ever
gets used now it's converted :)
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jiri Kosina <jkosina@suse.cz>
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Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Jiri Kosina <jkosina@suse.cz>
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This gets open coded quite a bit and it's tricky to get right, so make a
generic version and convert some existing users over to it instead.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
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More bi_idx removal. This code was just open coding bio_clone(). This
could probably be further improved by using bio_advance() instead of
skipping over null pages, but that'd be a larger rework.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
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Had to shuffle the code around a bit (where bi_rw and bi_end_io were
set), but shouldn't really be anything tricky here
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
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Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
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More prep work for immutable bio vecs, mainly getting rid of references
to bi_idx.
bio_reset was being open coded in a few places. The one in sync_request
was a bit nontrivial to convert, so could use some extra eyeballs.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
Acked-by: NeilBrown <neilb@suse.de>
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Random cleanup - this code was duplicated and it's not really specific
to md.
Also added the ability to return the actual error code.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
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More prep work for immutable bvecs/effecient bio splitting - usage of
bi_vcnt has to be auditing, so getting rid of all the unnecessary usage
makes that easier.
Plus, bio_segments() is really what this code wanted, as it respects the
current value of bi_idx.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Eric Moore <Eric.Moore@lsi.com>
CC: "James E.J. Bottomley" <JBottomley@parallels.com>
CC: linux-scsi@vger.kernel.org
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For immutable bvecs, all bi_idx usage needs to be audited - so here
we're removing all the unnecessary uses.
Most of these are places where it was being initialized on a bio that
was just allocated, a few others are conversions to standard macros.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
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In the current code bio_split() won't be seeing partially completed bios
so this doesn't change any behaviour, but this makes the code a bit
clearer as to what bio_split() actually requires.
The immediate purpose of the patch is removing unnecessary bi_idx
references, but the end goal is to allow partial completed bios to be
submitted, which along with immutable biovecs enables effecient bio
splitting.
Some of the callers were (double) checking that bios could be split, so
update their checks too.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Lars Ellenberg <drbd-dev@lists.linbit.com>
CC: Neil Brown <neilb@suse.de>
CC: Martin K. Petersen <martin.petersen@oracle.com>
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Bunch of places in the code weren't using it where they could be -
this'll reduce the size of the patch that puts bi_sector/bi_size/bi_idx
into a struct bvec_iter.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: "Ed L. Cashin" <ecashin@coraid.com>
CC: Nick Piggin <npiggin@kernel.dk>
CC: Jiri Kosina <jkosina@suse.cz>
CC: Jim Paris <jim@jtan.com>
CC: Geoff Levand <geoff@infradead.org>
CC: Alasdair Kergon <agk@redhat.com>
CC: dm-devel@redhat.com
CC: Neil Brown <neilb@suse.de>
CC: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Ed Cashin <ecashin@coraid.com>
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Just a little convenience macro - main reason to add it now is preparing
for immutable bio vecs, it'll reduce the size of the patch that puts
bi_sector/bi_size/bi_idx into a struct bvec_iter.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Lars Ellenberg <drbd-dev@lists.linbit.com>
CC: Jiri Kosina <jkosina@suse.cz>
CC: Alasdair Kergon <agk@redhat.com>
CC: dm-devel@redhat.com
CC: Neil Brown <neilb@suse.de>
CC: Martin Schwidefsky <schwidefsky@de.ibm.com>
CC: Heiko Carstens <heiko.carstens@de.ibm.com>
CC: linux-s390@vger.kernel.org
CC: Chris Mason <chris.mason@fusionio.com>
CC: Steven Whitehouse <swhiteho@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
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Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
Acked-by: NeilBrown <neilb@suse.de>
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Converts it to use bio_advance(), simplifying it quite a bit in the
process.
Note that req_bio_endio() now always calls bio_advance() - which means
it always loops over the biovec, not just on partial completions. Don't
expect it to affect performance, but worth noting.
Tested it by forcing partial updates, and dumping before and after on
various bio/bvec fields when doing a partial update.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
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This is prep work for immutable bio vecs; we first want to centralize
where bvecs are modified.
Next two patches convert some existing code to use this function.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
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This adds a pointer to the bvec array to struct bio_integrity_payload,
instead of the bvecs always being inline; then the bvecs are allocated
with bvec_alloc_bs().
Changed bvec_alloc_bs() and bvec_free_bs() to take a pointer to a
mempool instead of the bioset, so that bio integrity can use a different
mempool for its bvecs, and thus avoid a potential deadlock.
This is eventually for immutable bio vecs - immutable bvecs aren't
useful if we still have to copy them, hence the need for the pointer.
Less code is always nice too, though.
Also, bio_integrity_alloc() was using fs_bio_set if no bio_set was
specified. This was wrong - using the bio_set doesn't protect us from
memory allocation failures, because we just used kmalloc for the
bio_integrity_payload. But it does introduce the possibility of
deadlock, if for some reason we weren't supposed to be using fs_bio_set.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Martin K. Petersen <martin.petersen@oracle.com>
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bio_integrity_split() seemed to be confusing pointers and arrays -
bip_vec in bio_integrity_payload was an array appended to the end of the
payload, so the bio_vecs in struct bio_pair should have come after the
bio_integrity_payload they're for.
Fix it by making bip_vec a pointer to the inline vecs - a later patch is
going to make more use of this pointer.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Martin K. Petersen <martin.petersen@oracle.com>
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Previously, if we ever try to allocate more than once from the same bio
set while running under generic_make_request() (i.e. a stacking block
driver), we risk deadlock.
This is because of the code in generic_make_request() that converts
recursion to iteration; any bios we submit won't actually be submitted
(so they can complete and eventually be freed) until after we return -
this means if we allocate a second bio, we're blocking the first one
from ever being freed.
Thus if enough threads call into a stacking block driver at the same
time with bios that need multiple splits, and the bio_set's reserve gets
used up, we deadlock.
This can be worked around in the driver code - we could check if we're
running under generic_make_request(), then mask out __GFP_WAIT when we
go to allocate a bio, and if the allocation fails punt to workqueue and
retry the allocation.
But this is tricky and not a generic solution. This patch solves it for
all users by inverting the previously described technique. We allocate a
rescuer workqueue for each bio_set, and then in the allocation code if
there are bios on current->bio_list we would be blocking, we punt them
to the rescuer workqueue to be submitted.
This guarantees forward progress for bio allocations under
generic_make_request() provided each bio is submitted before allocating
the next, and provided the bios are freed after they complete.
Note that this doesn't do anything for allocation from other mempools.
Instead of allocating per bio data structures from a mempool, code
should use bio_set's front_pad.
Tested it by forcing the rescue codepath to be taken (by disabling the
first GFP_NOWAIT) attempt, and then ran it with bcache (which does a lot
of arbitrary bio splitting) and verified that the rescuer was being
invoked.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Muthukumar Ratty <muthur@gmail.com>
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This is prep work for the next patch, which embeds a struct bio_list in
struct bio_set.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
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Commit 1d9d8639c063 ("perf,x86: fix kernel crash with PEBS/BTS after
suspend/resume") introduces a link failure since
perf_restore_debug_store() is only defined for CONFIG_CPU_SUP_INTEL:
arch/x86/power/built-in.o: In function `restore_processor_state':
(.text+0x45c): undefined reference to `perf_restore_debug_store'
Fix it by defining the dummy function appropriately.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Commit 1d9d8639c063 ("perf,x86: fix kernel crash with PEBS/BTS after
suspend/resume") fixed a crash when doing PEBS performance profiling
after resuming, but in using init_debug_store_on_cpu() to restore the
DS_AREA mtrr it also resulted in a new WARN_ON() triggering.
init_debug_store_on_cpu() uses "wrmsr_on_cpu()", which in turn uses CPU
cross-calls to do the MSR update. Which is not really valid at the
early resume stage, and the warning is quite reasonable. Now, it all
happens to _work_, for the simple reason that smp_call_function_single()
ends up just doing the call directly on the CPU when the CPU number
matches, but we really should just do the wrmsr() directly instead.
This duplicates the wrmsr() logic, but hopefully we can just remove the
wrmsr_on_cpu() version eventually.
Reported-and-tested-by: Parag Warudkar <parag.lkml@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs fixes from Chris Mason:
"Eric's rcu barrier patch fixes a long standing problem with our
unmount code hanging on to devices in workqueue helpers. Liu Bo
nailed down a difficult assertion for in-memory extent mappings."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: fix warning of free_extent_map
Btrfs: fix warning when creating snapshots
Btrfs: return as soon as possible when edquot happens
Btrfs: return EIO if we have extent tree corruption
btrfs: use rcu_barrier() to wait for bdev puts at unmount
Btrfs: remove btrfs_try_spin_lock
Btrfs: get better concurrency for snapshot-aware defrag work
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Users report that an extent map's list is still linked when it's actually
going to be freed from cache.
The story is that
a) when we're going to drop an extent map and may split this large one into
smaller ems, and if this large one is flagged as EXTENT_FLAG_LOGGING which means
that it's on the list to be logged, then the smaller ems split from it will also
be flagged as EXTENT_FLAG_LOGGING, and this is _not_ expected.
b) we'll keep ems from unlinking the list and freeing when they are flagged with
EXTENT_FLAG_LOGGING, because the log code holds one reference.
The end result is the warning, but the truth is that we set the flag
EXTENT_FLAG_LOGGING only during fsync.
So clear flag EXTENT_FLAG_LOGGING for extent maps split from a large one.
Reported-by: Johannes Hirte <johannes.hirte@fem.tu-ilmenau.de>
Reported-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild
Pull kbuild fix from Michal Marek:
"One fix for for make headers_install/headers_check to not require make
3.81. The requirement has been accidentally introduced in 3.7."
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
kbuild: fix make headers_check with make 3.80
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Pull OpenRISC bug fixes from Jonas Bonn:
- The GPIO descriptor work has exposed how broken the non-GPIOLIB bits
for OpenRISC were. We now require GPIOLIB as this is the preferred
way forward.
- The system.h split introduced a bug in llist.h for arches using
asm-generic/cmpxchg.h directly, which is currently only OpenRISC.
The patch here moves two defines from asm-generic/atomic.h to
asm-generic/cmpxchg.h to make things work as they should.
- The VIRT_TO_BUS selector was added for OpenRISC, but OpenRISC does
not have the virt_to_bus methods, so there's a patch to remove it
again.
* tag 'for-3.9-rc3' of git://openrisc.net/jonas/linux:
openrisc: remove HAVE_VIRT_TO_BUS
asm-generic: move cmpxchg*_local defs to cmpxchg.h
openrisc: require gpiolib
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc fixes from Greg Kroah-Hartman:
"Here are some tiny fixes for the w1 drivers and the final removal
patch for getting rid of CONFIG_EXPERIMENTAL (all users of it are now
gone from your tree, this just drops the Kconfig item itself.)
All have been in the linux-next tree for a while"
* tag 'char-misc-3.9-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
final removal of CONFIG_EXPERIMENTAL
w1: fix oops when w1_search is called from netlink connector
w1-gpio: fix unused variable warning
w1-gpio: remove erroneous __exit and __exit_p()
ARM: w1-gpio: fix erroneous gpio requests
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git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Pull sound fixes from Takashi Iwai:
"A collection of small fixes, as expected for the middle rc:
- A couple of fixes for potential NULL dereferences and out-of-range
array accesses revealed by static code parsers
- A fix for the wrong error handling detected by trinity
- A regression fix for missing audio on some MacBooks
- CA0132 DSP loader fixes
- Fix for EAPD control of IDT codecs on machines w/o speaker
- Fix a regression in the HD-audio widget list parser code
- Workaround for the NuForce UDH-100 USB audio"
* tag 'sound-3.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: hda - Fix missing EAPD/GPIO setup for Cirrus codecs
sound: sequencer: cap array index in seq_chn_common_event()
ALSA: hda/ca0132 - Remove extra setting of dsp_state.
ALSA: hda/ca0132 - Check download state of DSP.
ALSA: hda/ca0132 - Check if dspload_image succeeded.
ALSA: hda - Disable IDT eapd_switch if there are no internal speakers
ALSA: hda - Fix snd_hda_get_num_raw_conns() to return a correct value
ALSA: usb-audio: add a workaround for the NuForce UDH-100
ALSA: asihpi - fix potential NULL pointer dereference
ALSA: seq: Fix missing error handling in snd_seq_timer_open()
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git://git.linaro.org/people/mszyprowski/linux-dma-mapping
Pull DMA-mapping fix from Marek Szyprowski:
"An important fix for all ARM architectures which use ZONE_DMA.
Without it dma_alloc_* calls with GFP_ATOMIC flag might have allocated
buffers outsize DMA zone."
* 'fixes-for-3.9' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping:
ARM: DMA-mapping: add missing GFP_DMA flag for atomic buffer allocation
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git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-fixes
Pull MFD fixes from Samuel Ortiz:
"This is the first batch of MFD fixes for 3.9.
With this one we have:
- An ab8500 build failure fix.
- An ab8500 device tree parsing fix.
- A fix for twl4030_madc remove routine to work properly (when
built-in).
- A fix for properly registering palmas interrupt handler.
- A fix for omap-usb init routine to actually write into the
hostconfig register.
- A couple of warning fixes for ab8500-gpadc and tps65912"
* tag 'mfd-fixes-3.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-fixes:
mfd: twl4030-madc: Remove __exit_p annotation
mfd: ab8500: Kill "reg" property from binding
mfd: ab8500-gpadc: Complain if we fail to enable vtvout LDO
mfd: wm831x: Don't forward declare enum wm831x_auxadc
mfd: twl4030-audio: Fix argument type for twl4030_audio_disable_resource()
mfd: tps65912: Declare and use tps65912_irq_exit()
mfd: palmas: Provide irq flags through DT/platform data
mfd: Make AB8500_CORE select POWER_SUPPLY to fix build error
mfd: omap-usb-host: Actually update hostconfig
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git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging
Pull hwmon fixes from Guenter Roeck:
"Bug fixes for pmbus, ltc2978, and lineage-pem drivers
Added specific maintainer for some hwmon drivers"
* tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
hwmon: (pmbus/ltc2978) Fix temperature reporting
hwmon: (pmbus) Fix krealloc() misuse in pmbus_add_attribute()
hwmon: (lineage-pem) Add missing terminating entry for pem_[input|fan]_attributes
MAINTAINERS: Add maintainer for MAX6697, INA209, and INA2XX drivers
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This patch fixes a kernel crash when using precise sampling (PEBS)
after a suspend/resume. Turns out the CPU notifier code is not invoked
on CPU0 (BP). Therefore, the DS_AREA (used by PEBS) is not restored properly
by the kernel and keeps it power-on/resume value of 0 causing any PEBS
measurement to crash when running on CPU0.
The workaround is to add a hook in the actual resume code to restore
the DS Area MSR value. It is invoked for all CPUS. So for all but CPU0,
the DS_AREA will be restored twice but this is harmless.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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During the transition to the generic parser, the hook to the codec
specific automute function was forgotten. This resulted in the silent
output on some MacBooks.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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"chn" here is a number between 0 and 255, but ->chn_info[] only has
16 elements so there is a potential write beyond the end of the
array.
If the seq_mode isn't SEQ_2 then we let the individual drivers
(either opl3.c or midi_synth.c) handle it. Those functions all
do a bounds check on "chn" so I haven't changed anything here.
The opl3.c driver has up to 18 channels and not 16.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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4740f73fe5 "mfd: remove use of __devexit" removed the __devexit annotation
on the twl4030_madc_remove function, but left an __exit_p() present on the
pointer to this function. Using __exit_p was as wrong with the devexit in
place as it is now, but now we get a gcc warning about an unused function.
In order for the twl4030_madc_remove to work correctly in built-in code, we
have to remove the __exit_p.
Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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spec->dsp_state is initialized to DSP_DOWNLOAD_INIT, no need to reset
and check it in ca0132_download_dsp().
Signed-off-by: Dylan Reid <dgreid@chromium.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Instead of using the dspload_is_loaded() function, check the dsp_state
that is kept in the spec. The dspload_is_loaded() function returns
true if the DSP transfer was never started. This false-positive leads
to multiple second delays when ca0132_setup_efaults() times out on
each write.
Signed-off-by: Dylan Reid <dgreid@chromium.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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If dspload_image() fails, it was ignored and dspload_wait_loaded() was
still called. dsp_loaded should never be set to true in this case,
skip it. The check in dspload_wait_loaded() return true if the DSP is
loaded or if it never started.
Signed-off-by: Dylan Reid <dgreid@chromium.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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The vm_flags introduced in 6d7825b10dbe ("mm/fremap.c: fix oops on error
path") is supposed to avoid a compiler warning about unitialized
vm_flags without changing the generated code.
However I am concerned that this is going to be very brittle, and fail
with some compiler versions. The failure could be either of:
- compiler could actually load vma->vm_flags before checking for the
!vma condition, thus reintroducing the oops
- compiler could optimize out the !vma check, since the pointer just got
dereferenced shortly before (so the compiler knows it can't be NULL!)
I propose reversing this part of the change and initializing vm_flags to 0
just to avoid the bogus uninitialized use warning.
Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Tommi Rantala <tt.rantala@gmail.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/paulmck/linux-rcu
Pull fix for hlist_entry_safe() regression from Paul McKenney:
"This contains a single commit that fixes a regression in
hlist_entry_safe(). This macro references its argument twice, which
can cause NULL-pointer errors. This commit applies a gcc statement
expression, creating a temporary variable to avoid the double
reference. This has been posted to LKML at
https://lkml.org/lkml/2013/3/9/75.
Kudos to CAI Qian, whose testing uncovered this, to Eric Dumazet, who
spotted root cause, and to Li Zefan, who tested this commit."
* 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
list: Fix double fetch of pointer in hlist_entry_safe()
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The current version of hlist_entry_safe() fetches the pointer twice,
once to test for NULL and the other to compute the offset back to the
enclosing structure. This is OK for normal lock-based use because in
that case, the pointer cannot change. However, when the pointer is
protected by RCU (as in "rcu_dereference(p)"), then the pointer can
change at any time. This use case can result in the following sequence
of events:
1. CPU 0 invokes hlist_entry_safe(), fetches the RCU-protected
pointer as sees that it is non-NULL.
2. CPU 1 invokes hlist_del_rcu(), deleting the entry that CPU 0
just fetched a pointer to. Because this is the last entry
in the list, the pointer fetched by CPU 0 is now NULL.
3. CPU 0 refetches the pointer, obtains NULL, and then gets a
NULL-pointer crash.
This commit therefore applies gcc's "({ })" statement expression to
create a temporary variable so that the specified pointer is fetched
only once, avoiding the above sequence of events. Please note that
it is the caller's responsibility to use rcu_dereference() as needed.
This allows RCU-protected uses to work correctly without imposing
any additional overhead on the non-RCU case.
Many thanks to Eric Dumazet for spotting root cause!
Reported-by: CAI Qian <caiqian@redhat.com>
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Li Zefan <lizefan@huawei.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull ext2, ext3, reiserfs, quota fixes from Jan Kara:
"A fix for regression in ext2, and a format string issue in ext3. The
rest isn't too serious."
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
ext2: Fix BUG_ON in evict() on inode deletion
reiserfs: Use kstrdup instead of kmalloc/strcpy
ext3: Fix format string issues
quota: add missing use of dq_data_lock in __dquot_initialize
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Creating snapshot passes extent_root to commit its transaction,
but it can lead to the warning of checking root for quota in
the __btrfs_end_transaction() when someone else is committing
the current transaction. Since we've recorded the needed root
in trans_handle, just use it to get rid of the warning.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
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If one of qgroup fails to reserve firstly, we should return immediately,
it is unnecessary to continue check.
Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
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The callers of lookup_inline_extent_info all handle getting an error back
properly, so return an error if we have corruption instead of being a jerk and
panicing. Still WARN_ON() since this is kind of crucial and I've been seeing it
a bit too much recently for my taste, I think we're doing something wrong
somewhere. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
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Doing this would reliably fail with -EBUSY for me:
# mount /dev/sdb2 /mnt/scratch; umount /mnt/scratch; mkfs.btrfs -f /dev/sdb2
...
unable to open /dev/sdb2: Device or resource busy
because mkfs.btrfs tries to open the device O_EXCL, and somebody still has it.
Using systemtap to track bdev gets & puts shows a kworker thread doing a
blkdev put after mkfs attempts a get; this is left over from the unmount
path:
btrfs_close_devices
__btrfs_close_devices
call_rcu(&device->rcu, free_device);
free_device
INIT_WORK(&device->rcu_work, __free_device);
schedule_work(&device->rcu_work);
so unmount might complete before __free_device fires & does its blkdev_put.
Adding an rcu_barrier() to btrfs_close_devices() causes unmount to wait
until all blkdev_put()s are done, and the device is truly free once
unmount completes.
Cc: stable@vger.kernel.org
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
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