- 03 Apr, 2013 10 commits
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J. Bruce Fields authored
Once we drop the lock here there's nothing keeping the client around: the only lock still held is the xpt_lock on this socket, but this socket no longer has any connection with the client so there's no way for other code to know we're still using the client. The solution is simple: all nfsd4_probe_callback does is set a few variables and queue some work, so there's no reason we can't just keep it under the lock. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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J. Bruce Fields authored
Dropping the session's reference count after the client's means we leave a window where the session's se_client pointer is NULL. An xpt_user callback that encounters such a session may then crash: [ 303.956011] BUG: unable to handle kernel NULL pointer dereference at 0000000000000318 [ 303.959061] IP: [<ffffffff81481a8e>] _raw_spin_lock+0x1e/0x40 [ 303.959061] PGD 37811067 PUD 3d498067 PMD 0 [ 303.959061] Oops: 0002 [#8] PREEMPT SMP [ 303.959061] Modules linked in: md5 nfsd auth_rpcgss nfs_acl snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_page_alloc microcode psmouse snd_timer serio_raw pcspkr evdev snd soundcore i2c_piix4 i2c_core intel_agp intel_gtt processor button nfs lockd sunrpc fscache ata_generic pata_acpi ata_piix uhci_hcd libata btrfs usbcore usb_common crc32c scsi_mod libcrc32c zlib_deflate floppy virtio_balloon virtio_net virtio_pci virtio_blk virtio_ring virtio [ 303.959061] CPU 0 [ 303.959061] Pid: 264, comm: nfsd Tainted: G D 3.8.0-ARCH+ #156 Bochs Bochs [ 303.959061] RIP: 0010:[<ffffffff81481a8e>] [<ffffffff81481a8e>] _raw_spin_lock+0x1e/0x40 [ 303.959061] RSP: 0018:ffff880037877dd8 EFLAGS: 00010202 [ 303.959061] RAX: 0000000000000100 RBX: ffff880037a2b698 RCX: ffff88003d879278 [ 303.959061] RDX: ffff88003d879278 RSI: dead000000100100 RDI: 0000000000000318 [ 303.959061] RBP: ffff880037877dd8 R08: ffff88003c5a0f00 R09: 0000000000000002 [ 303.959061] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 [ 303.959061] R13: 0000000000000318 R14: ffff880037a2b680 R15: ffff88003c1cbe00 [ 303.959061] FS: 0000000000000000(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000 [ 303.959061] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 303.959061] CR2: 0000000000000318 CR3: 000000003d49c000 CR4: 00000000000006f0 [ 303.959061] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 303.959061] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 303.959061] Process nfsd (pid: 264, threadinfo ffff880037876000, task ffff88003c1fd0a0) [ 303.959061] Stack: [ 303.959061] ffff880037877e08 ffffffffa03772ec ffff88003d879000 ffff88003d879278 [ 303.959061] ffff88003d879080 0000000000000000 ffff880037877e38 ffffffffa0222a1f [ 303.959061] 0000000000107ac0 ffff88003c22e000 ffff88003d879000 ffff88003c1cbe00 [ 303.959061] Call Trace: [ 303.959061] [<ffffffffa03772ec>] nfsd4_conn_lost+0x3c/0xa0 [nfsd] [ 303.959061] [<ffffffffa0222a1f>] svc_delete_xprt+0x10f/0x180 [sunrpc] [ 303.959061] [<ffffffffa0223d96>] svc_recv+0xe6/0x580 [sunrpc] [ 303.959061] [<ffffffffa03587c5>] nfsd+0xb5/0x140 [nfsd] [ 303.959061] [<ffffffffa0358710>] ? nfsd_destroy+0x90/0x90 [nfsd] [ 303.959061] [<ffffffff8107ae00>] kthread+0xc0/0xd0 [ 303.959061] [<ffffffff81010000>] ? perf_trace_xen_mmu_set_pte_at+0x50/0x100 [ 303.959061] [<ffffffff8107ad40>] ? kthread_freezable_should_stop+0x70/0x70 [ 303.959061] [<ffffffff814898ec>] ret_from_fork+0x7c/0xb0 [ 303.959061] [<ffffffff8107ad40>] ? kthread_freezable_should_stop+0x70/0x70 [ 303.959061] Code: ff ff 5d c3 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 55 65 48 8b 04 25 f0 c6 00 00 48 89 e5 83 80 44 e0 ff ff 01 b8 00 01 00 00 <3e> 66 0f c1 07 0f b6 d4 38 c2 74 0f 66 0f 1f 44 00 00 f3 90 0f [ 303.959061] RIP [<ffffffff81481a8e>] _raw_spin_lock+0x1e/0x40 [ 303.959061] RSP <ffff880037877dd8> [ 303.959061] CR2: 0000000000000318 [ 304.001218] ---[ end trace 2d809cd4a7931f5a ]--- [ 304.001903] note: nfsd[264] exited with preempt_count 2 Reported-by: Bryan Schumaker <bjschuma@netapp.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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J. Bruce Fields authored
If a client sets an owner (or group_owner or acl) attribute on open for create, and the mapping of that owner to an id fails, then we return BAD_OWNER. But BAD_OWNER is a seqid-mutating error, so we can't shortcut the open processing that case: we have to at least look up the owner so we can find the seqid to bump. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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J. Bruce Fields authored
This BUG_ON just crashes the thread a little earlier than it would otherwise--it doesn't seem useful. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Jeff Layton authored
We've now increased the size of the duplicate reply cache by quite a bit, but the number of hash buckets has not changed. So, we've gone from an average hash chain length of 16 in the old code to 4096 when the cache is its largest. Change the code to scale out the number of buckets with the max size of the cache. At the same time, we also need to fix the hash function since the existing one isn't really suitable when there are more than 256 buckets. Move instead to use the stock hash_32 function for this. Testing on a machine that had 2048 buckets showed that this gave a smaller longest:average ratio than the existing hash function: The formula here is longest hash bucket searched divided by average number of entries per bucket at the time that we saw that longest bucket: old hash: 68/(39258/2048) == 3.547404 hash_32: 45/(33773/2048) == 2.728807 Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Jeff Layton authored
The typical case with the DRC is a cache miss, so if we keep track of the max number of entries that we've ever walked over in a search, then we should have a reasonable estimate of the longest hash chain that we've ever seen. With that, we'll also keep track of the total size of the cache when we see the longest chain. In the case of a tie, we prefer to track the smallest total cache size in order to properly gauge the worst-case ratio of max vs. avg chain length. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Jeff Layton authored
For presenting statistics relating to duplicate reply cache. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Jeff Layton authored
Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Jeff Layton authored
Break out the function that compares the rqstp and checksum against a reply cache entry. While we're at it, track the efficacy of the checksum over the NFS data by tracking the cases where we would have incorrectly matched a DRC entry if we had not tracked it or the length. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Jeff Layton authored
The most common case is to do a search of the cache, followed by an insert. In the case where we have to allocate an entry off the slab, then we end up having to redo the search, which is wasteful. Better optimize the code for the common case by eliminating the initial search of the cache and always preallocating an entry. In the case of a cache hit, we'll end up just freeing that entry but that's preferable to an extra search. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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- 26 Mar, 2013 1 commit
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J. Bruce Fields authored
Since we only enforce an upper bound, not a lower bound, a "negative" length can get through here. The symptom seen was a warning when we attempt to a kmalloc with an excessive size. Reported-by: Toralf Förster <toralf.foerster@gmx.de> Cc: stable@kernel.org Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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- 22 Mar, 2013 1 commit
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Kent Overstreet authored
vfs_writev() updates the offset argument - but the code then passes the offset to vfs_fsync_range(). Since offset now points to the offset after what was just written, this is probably not what was intended Introduced by face1502 "nfsd: use vfs_fsync_range(), not O_SYNC, for stable writes". Signed-off-by: Kent Overstreet <koverstreet@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: stable@vger.kernel.org Reviewed-by: Zach Brown <zab@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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- 18 Mar, 2013 2 commits
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Jeff Layton authored
If we end up doing "goto out_nomem" in this function, we'll call nfsd_reply_cache_shutdown. That will attempt to walk the LRU list and free entries, but that list may not be initialized yet if the server is starting up for the first time. It's also possible for the shrinker to kick in before we've initialized the LRU list. Rearrange the initialization so that the LRU list_head and cache size are initialized before doing any of the allocations that might fail. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Jeff Layton authored
It's not safe to call hlist_del() on a newly initialized hlist_node. That leads to a NULL pointer dereference. Only do that if the entry is hashed. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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- 17 Mar, 2013 4 commits
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Linus Torvalds authored
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David Rientjes authored
Commit 1d9d8639 ("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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Linus Torvalds authored
Commit 1d9d8639 ("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-btrfsLinus Torvalds authored
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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- 16 Mar, 2013 8 commits
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Liu Bo authored
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/kbuildLinus Torvalds authored
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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git://openrisc.net/jonas/linuxLinus Torvalds authored
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-miscLinus Torvalds authored
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/soundLinus Torvalds authored
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-mappingLinus Torvalds authored
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-fixesLinus Torvalds authored
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-stagingLinus Torvalds authored
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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- 15 Mar, 2013 8 commits
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Stephane Eranian authored
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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Takashi Iwai authored
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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Dan Carpenter authored
"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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Arnd Bergmann authored
4740f73f "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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Dylan Reid authored
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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Dylan Reid authored
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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Dylan Reid authored
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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Michel Lespinasse authored
The vm_flags introduced in 6d7825b1 ("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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- 14 Mar, 2013 6 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcuLinus Torvalds authored
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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Paul E. McKenney authored
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-fsLinus Torvalds authored
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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Liu Bo authored
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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Wang Shilong authored
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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Josef Bacik authored
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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