A forced undef of a config value was used for testing and was
accidently left in during the final commit. This causes x86 to
run slower than needed while running function tracing as well
as causes the function graph selftest to fail when DYNMAIC_FTRACE
is not set. This is because the code in MCOUNT expects the ftrace
code to be processed with the config value set that happened to
be forced not set.

The forced config option was left in by:
    commit 6331c28c
    ftrace: Fix dynamic selftest failure on some archs

Link: http://lkml.kernel.org/r/20111102150255.GA6973@debian

Cc: stable@vger.kernel.org
Reported-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Though not all events have field 'prev_pid', it was allowed to do this:

  # echo 'prev_pid == 100' > events/sched/filter

but commit 75b8e982 (tracing/filter: Swap
entire filter of events) broke it without any reason.

Link: http://lkml.kernel.org/r/4EAF46CF.8040408@cn.fujitsu.comSigned-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Fix a bug introduced by e9dbfae5, which prevents event_subsystem from
ever being released.

Ref_count was added to keep track of subsystem users, not for counting
events.  Subsystem is created with ref_count = 1, so there is no need to
increment it for every event, we have nr_events for that.  Fix this by
touching ref_count only when we actually have a new user -
subsystem_open().

Cc: stable@vger.kernel.org
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Link: http://lkml.kernel.org/r/1320052062-7846-1-git-send-email-idryomov@gmail.comSigned-off-by: Steven Rostedt <rostedt@goodmis.org>

Merge branch 'tip/perf/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/urgent

When you do:
        $ perf record -e cycles,cycles,cycles noploop 10

You expect about 10,000 samples for each event, i.e., 10s at
1000samples/sec. However, this is not what's happening. You
get much fewer samples, maybe 3700 samples/event:

$ perf report -D | tail -15
Aggregated stats:
           TOTAL events:      10998
            MMAP events:         66
            COMM events:          2
          SAMPLE events:      10930
cycles stats:
           TOTAL events:       3644
          SAMPLE events:       3644
cycles stats:
           TOTAL events:       3642
          SAMPLE events:       3642
cycles stats:
           TOTAL events:       3644
          SAMPLE events:       3644

On a Intel Nehalem or even AMD64, there are 4 counters capable
of measuring cycles, so there is plenty of space to measure those
events without multiplexing (even with the NMI watchdog active).
And even with multiplexing, we'd expect roughly the same number
of samples per event.

The root of the problem was that when the event that caused the buffer
to become full was not the first event passed on the cmdline, the user
notification would get lost. The notification was sent to the file
descriptor of the overflowed event but the perf tool was not polling
on it.  The perf tool aggregates all samples into a single buffer,
i.e., the buffer of the first event. Consequently, it assumes
notifications for any event will come via that descriptor.

The seemingly straight forward solution of moving the waitq into the
ringbuffer object doesn't work because of life-time issues. One could
perf_event_set_output() on a fd that you're also blocking on and cause
the old rb object to be freed while its waitq would still be
referenced by the blocked thread -> FAIL.

Therefore link all events to the ringbuffer and broadcast the wakeup
from the ringbuffer object to all possible events that could be waited
upon. This is rather ugly, and we're open to better solutions but it
works for now.
Reported-by: Stephane Eranian <eranian@google.com>
Finished-by: Stephane Eranian <eranian@google.com>
Reviewed-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20111126014731.GA7030@quadSigned-off-by: Ingo Molnar <mingo@elte.hu>

On AMD family 10h we see firmware bug messages like the following:

 [Firmware Bug]: cpu 6, try to use APIC500 (LVT offset 0) for vector 0x10400, but the register is already in use for vector 0xf9 on another cpu
 [Firmware Bug]: cpu 6, IBS interrupt offset 0 not available (MSRC001103A=0x0000000000000100)
 [Firmware Bug]: using offset 1 for IBS interrupts
 [Firmware Bug]: workaround enabled for IBS LVT offset
 perf: AMD IBS detected (0x00000007)

We always see this, since the offsets are not assigned by the BIOS for
this family. Force LVT offset assignment in this case. If the OS
assignment fails, fallback to BIOS settings and try to setup this.

The fallback to BIOS settings weakens the family check since
force_ibs_eilvt_setup() may fail e.g. in case of virtual machines.
But setup may still succeed if BIOS offsets are correct.

Other families don't have a workaround implemented that assigns LVT
offsets. It's ok, to drop calling force_ibs_eilvt_setup() for that
families.

With the patch the [Firmware Bug] messages vanish. We see now:

 IBS: LVT offset 1 assigned
 perf: AMD IBS detected (0x00000007)
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20111109162225.GO12451@erda.amd.comSigned-off-by: Ingo Molnar <mingo@elte.hu>

Cc: Stephane Eranian <eranian@google.com>
Cc: stable@kernel.org
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

ftrace_event_call->filter is sched RCU protected but didn't use
rcu_assign_pointer().  Use it.

TODO: Add proper __rcu annotation to call->filter and all its users.

-v2: Use RCU_INIT_POINTER() for %NULL clearing as suggested by Eric.

Link: http://lkml.kernel.org/r/20111123164949.GA29639@google.com

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@kernel.org # (2.6.39+)
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

commit 5d67be97 added the option to specify a range of CPUs of interest,
but does not catch an invalid CPU list:

$ perf script -c foo
Segmentation fault (core dumped)

Cc: Anton Blanchard <anton@samba.org>
Link: http://lkml.kernel.org/r/1321206327-5881-1-git-send-email-dsahern@gmail.comSigned-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Recently we made perf_evsel__init call hists__init, which broke the perf
python binding:

[root@emilia linux]# ./tools/perf/python/twatch.py
Traceback (most recent call last):
  File "./tools/perf/python/twatch.py", line 16, in <module>
    import perf
ImportError: /home/acme/git/build/perf/python/perf.so: undefined symbol: hists__init

Fix it by moving the hists__init function to its only caller, evsel.c.

This way we avoid dragging in other parts of tools/perf/util/ to the
perf python binding.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-5nffmdt5mu6ozxgj54oi4qon@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Now that the core offcore support is fixed up (thanks Stephane) and we
have sane generic events utilizing them, re-enable the raw access to
the feature as well.

Note that it doesn't matter if you use event 0x1b7 or 0x1bb to specify
an offcore event, either one works and neither guarantees you'll end
up on a particular offcore MSR.

Based on original patch from: Vince Weaver <vweaver1@eecs.utk.edu>.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Vince Weaver <vweaver1@eecs.utk.edu>.
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.00.1108031200390.703@cl320.eecs.utk.eduSigned-off-by: Ingo Molnar <mingo@elte.hu>

People (Linus) objected to using -ENOSPC to signal not having enough
resources on the PMU to satisfy the request. Use -EINVAL.
Requested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-xv8geaz2zpbjhlx0svmpp28n@git.kernel.org
[ merged to newer kernel, fixed up MIPS impact ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Do not set task_ctx pointer during sched_in if there are no
events associated with the context.  Otherwise if during task
execution total number of events in the system will become zero
perf_event_context_sched_out() will not be called and cpuctx->task_ctx
will be left with a stale value.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20111023171033.GI17571@redhat.comSigned-off-by: Ingo Molnar <mingo@elte.hu>

Masami spotted that we always try to decode the instruction stream as
64bit instructions when running a 64bit kernel, this doesn't work for
ia32-compat proglets.

Use TIF_IA32 to detect if we need to use the 32bit instruction
decoder.
Reported-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: stable@kernel.org
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

* 'rmobile-fixes-for-linus' of git://github.com/pmundt/linux-sh:
  ARM: mach-shmobile: cpuidle single/global and last_state fixes
  ARM: mach-shmobile: move helper macro PORTCR to sh_pfc.h
  ARM: mach-shmobile: move helper macro PORT_xx to sh_pfc.h
  ARM: mach-shmobile: move helper macro PORT_DATA_xx to sh_pfc.h
  ARM: mach-shmobile: ap4evb: remove white space from end of line
  ARM: mach-shmobile: clock-sh7372: remove un-necessary index
  ARM: mach-shmobile: kota2: add comment out separator
  ARM: mach-shmobile: sh73a0: add MMC data pin pull-up

* 'sh-fixes-for-linus' of git://github.com/pmundt/linux-sh:
  mailmap: Fix up some renesas attributions
  sh: clkfwk: Kill off remaining debugfs cruft.
  drivers: sh: Kill off dead pathname for runtime PM stub.
  drivers: sh: Generalize runtime PM platform stub.
  sh: Wire up process_vm syscalls.
  sh: clkfwk: add clk_rate_mult_range_round()
  serial: sh-sci: Fix up SH-2A SCIF support.
  sh: Fix cached/uncaced address calculation in 29bit mode

* git://github.com/rustyrussell/linux:
  virtio-pci: fix use after free

Commit 31a3ddda introduced
a use after free in virtio-pci. The main issue is
that the release method signals removal of the virtio device,
while remove signals removal of the pci device.

For example, on driver removal or hot-unplug,
virtio_pci_release_dev is called before virtio_pci_remove.
We then might get a crash as virtio_pci_remove tries to use the
device freed by virtio_pci_release_dev.

We allocate/free all resources together with the
pci device, so we can leave the release method empty.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/radeon/kms/combios: fix dynamic allocation of PM clock modes

After commit e978aa7d ("cpuidle: Move dev->last_residency update to
driver enter routine; remove dev->last_state") setting acpi_idle_suspend
to 1 by acpi_processor_suspend() causes the ACPI cpuidle routines to
return error codes continuously, which in turn causes cpuidle to lock up
(hard).

However, acpi_idle_suspend doesn't appear to be useful for any
particular purpose (it's racy and doesn't really provide any real
protection), so it can be removed, which makes the problem go away.
Reported-and-tested-by: Tomas M. <tmezzadra@gmail.com>
Reported-and-tested-by: Ferenc Wagner <wferi@niif.hu>
Tested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

I missed the combios path when I updated the atombios pm code.

Reported by amarsh04 on IRC.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  arm/imx: fix imx6q mmc error when mounting rootfs
  arm/imx: fix AUTO_ZRELADDR selection
  arm/imx: fix the references to ARCH_MX3
  ARM: mx51/53: set pwm clock parent to ipg_perclk
  arm/tegra: enable headphone detection gpio on seaboard
  arm/dt: Fix ventana SDHCI power-gpios
  arm/tegra: Don't create duplicate gpio and pinmux devices
  ARM: at91: Fix USBA gadget registration
  atmel/spi: fix missing probe
  at91/yl-9200: Fix section mismatch
  at91: vmalloc fix missing AT91_VIRT_BASE define
  ARM: at91: usart: drop static map regs for dbgu
  ARM: picoxcell: add extra temp register to addruart
  ARM: msm: fix compilation flags for MSM_SCM
  arm/mxs: fix mmc device adding for mach-mx28evk
  ARM: mxc: Remove test_for_ltirq
  ARM:i.MX: fix build error in clock-mx51-mx53.c
  ARM:i.MX: fix build error in tzic/avic.c
  ARM: mxc: fix local timer interrupt handling
  msm: boards: Fix fallout from removal of machine_desc in fixup

The variable i is removed by commit ded84337
"[CPUFREQ] db8500: remove unneeded for loop iteration over freq_table",
but current code to print available frequencies still uses the i variable.
Thus add the i variable back to fix below buld error:

  CC      drivers/cpufreq/db8500-cpufreq.o
drivers/cpufreq/db8500-cpufreq.c: In function 'db8500_cpufreq_init':
drivers/cpufreq/db8500-cpufreq.c:123: error: 'i' undeclared (first use in this function)
drivers/cpufreq/db8500-cpufreq.c:123: error: (Each undeclared identifier is reported only once
drivers/cpufreq/db8500-cpufreq.c:123: error: for each function it appears in.)
make[2]: *** [drivers/cpufreq/db8500-cpufreq.o] Error 1
make[1]: *** [drivers/cpufreq] Error 2
make: *** [drivers] Error 2

This patch also fixes using uninitialized i variable as array index.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Dave Jones <davej@redhat.com>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k: (29 commits)
  m68k/mac: Remove mac_irq_{en,dis}able() wrappers
  m68k/irq: Remove obsolete support for user vector interrupt fixups
  m68k/irq: Remove obsolete m68k irq framework
  m68k/q40: Convert Q40/Q60 to genirq
  m68k/sun3: Convert Sun3/3x to genirq
  m68k/sun3: Use the kstat_irqs_cpu() wrapper
  m68k/apollo: Convert Apollo to genirq
  m68k/vme: Convert VME to genirq
  m68k/hp300: Convert HP9000/300 and HP9000/400 to genirq
  m68k/mac: Optimize interrupts using chain handlers
  m68k/mac: Convert Mac to genirq
  m68k/amiga: Optimize interrupts using chain handlers
  m68k/amiga: Convert Amiga to genirq
  m68k/amiga: Refactor amiints.c
  m68k/atari: Remove code and comments about different irq types
  m68k/atari: Convert Atari to genirq
  m68k/irq: Add genirq support
  m68k/irq: Remove obsolete IRQ_FLG_* users
  m68k/irq: Rename {,__}m68k_handle_int()
  m68k/irq: Add m68k_setup_irq_controller()
  ...

* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
  [media] v4l2-ctrl: Send change events to all fh for auto cluster slave controls
  [media] v4l2-event: Don't set sev->fh to NULL on unsubscribe
  [media] v4l2-event: Remove pending events from fh event queue when unsubscribing
  [media] v4l2-event: Deny subscribing with a type of V4L2_EVENT_ALL
  [media] MAINTAINERS: add a maintainer for s5p-mfc driver
  [media] v4l: s5p-mfc: fix reported capabilities
  [media] media: vb2: reset queued list on REQBUFS(0) call
  [media] media: vb2: set buffer length correctly for all buffer types
  [media] media: vb2: add a check for uninitialized buffer
  [media] mxl111sf: fix build warning
  [media] mxl111sf: remove pointless if condition in mxl111sf_config_spi
  [media] mxl111sf: check for errors after mxl111sf_write_reg in mxl111sf_idac_config
  [media] mxl111sf: fix return value of mxl111sf_idac_config
  [media] uvcvideo: GET_RES should only be checked for BITMAP type menu controls

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc/kvm: Fix build failure with HV KVM and CBE
  powerpc/ps3: Fix lv1_gpu_attribute hcall
  powerpc/ps3: Fix PS3 repository build warnings
  powerpc/ps3: irq: Remove IRQF_DISABLED
  powerpc/irq: Remove IRQF_DISABLED
  powerpc/numa: NUMA topology support for PowerNV
  powerpc: Add System RAM to /proc/iomem
  powerpc: Add KVM as module to defconfigs
  powerpc/kvm: Fix build with older toolchains
  powerpc, tqm5200: update tqm5200_defconfig to fit for charon board.
  powerpc/5200: add support for charon board

* 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  kbuild: Fix missing system calls check on mips.

This needed the sfi IRQ 0xFF fix to go in first. It simply plumbs in the
bma023 driver with the firmware naming of it.
Signed-off-by: William Douglas <william.douglas@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Real world year equals the value in vrtc YEAR register plus an offset.
We used 1960 as the offset to make leap year consistent, but for a
device's first use, its YEAR register is 0 and the system year will
be parsed as 1960 which is not a valid UNIX time and will cause many
applications to fail mysteriously. So we use 1972 instead to fix this
issue.

Updated patch which adds a sanity check suggested by Mathias

This isn't a change in behaviour for systems, because 1972 is the one we
actually use. It's the old version in upstream which is out of sync with
all devices.
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fix a build error. CE4100 with no serial errors because the alternate
function is only a prototype not a null function as intended.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* 'upstream-linus' of git://github.com/jgarzik/libata-dev:
  pata_of_platform: Don't use NO_IRQ
  [libata] ahci: Add ASMedia ASM1061 support
  [libata] Issue SRST to Sil3726 PMP
  sata_sis.c: trivial spelling fix
  ahci_platform: use dev_get_platdata()
  [libata] libata-scsi.c: Add function parameter documentation

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  btrfs: rename the option to nospace_cache
  Btrfs: handle bio_add_page failure gracefully in scrub
  Btrfs: fix deadlock caused by the race between relocation
  Btrfs: only map pages if we know we need them when reading the space cache
  Btrfs: fix orphan backref nodes
  Btrfs: Abstract similar code for btrfs_block_rsv_add{, _noflush}
  Btrfs: fix unreleased path in btrfs_orphan_cleanup()
  Btrfs: fix no reserved space for writing out inode cache
  Btrfs: fix nocow when deleting the item
  Btrfs: tweak the delayed inode reservations again
  Btrfs: rework error handling in btrfs_mount()
  Btrfs: close devices on all error paths in open_ctree()
  Btrfs: avoid null dereference and leaks when bailing from open_ctree()
  Btrfs: fix subvol_name leak on error in btrfs_mount()
  Btrfs: fix memory leak in btrfs_parse_early_options()
  Btrfs: fix our reservations for updating an inode when completing io
  Btrfs: fix oops on NULL trans handle in btrfs_truncate
  btrfs: fix double-free 'tree_root' in 'btrfs_mount()'

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: usb-audio: Use kmemdup rather than duplicating its implementation
  ALSA: hda - Re-enable the check NO_PRESENCE misc bit
  ALSA: vmaster - Free slave-links when freeing the master element
  ALSA: hda - Don't add elements of other codecs to vmaster slave
  ALSA: intel8x0: improve virtual environment detection
  ALSA: intel8x0: move virtual environment detection code into one place
  ALSA: snd_usb_audio: add Logitech HD Webcam c510 to quirk-384
  ALSA: hda - fix internal mic on Dell Vostro 3500 laptop
  ALSA: HDA: Remove quirk for Toshiba T110
  ALSA: usb-audio - Fix the missing volume quirks at delayed init
  ALSA: hda - Mute unused capture sources for Realtek codecs
  ALSA: intel8x0: Improve comments for VM optimization
  ASoC: Ensure we get an impedence reported for WM8958 jack detect
  ASoC: Don't use wm8994->control_data when requesting IRQs
  ASoC: Don't use wm8994->control_data in wm8994_readable_register()
  ASoC: Update git repository URL

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux: (42 commits)
  drm/radeon/kms/pm: switch to dynamically allocating clock mode array
  drm/radeon/kms: optimize r600_pm_profile_init
  drm/radeon/kms/pm: add a proper pm profile init function for fusion
  drm/radeon/kms: remove extraneous calls to radeon_pm_compute_clocks()
  drm/exynos: added padding to be 64-bit align.
  drm: fix kconfig unmet dependency warning
  drm: add some comments to drm_wait_vblank and drm_queue_vblank_event
  drm/radeon/benchmark: signedness bug in radeon_benchmark_move()
  drm: do not sleep on vblank while holding a mutex
  MAINTAINERS: exynos: Add EXYNOS DRM maintainer entry
  drm: try to restore previous CRTC config if mode set fails
  drm/radeon/kms: make an aux failure debug only
  drm: drop select of SLOW_WORK
  drm: serialize access to list of debugfs files
  drm/radeon/kms: fix use of vram scratch page on evergreen/ni
  drm/radeon: Make sure CS mutex is held across GPU reset.
  drm: Ensure string is null terminated.
  vmwgfx: Only allow 64x64 cursors
  vmwgfx: Initialize clip rect loop correctly in surface dirty
  vmwgfx: Close screen object system
  ...

* git://github.com/herbertx/crypto:
  crypto: algapi - Fix build problem with NET disabled
  crypto: user - Fix rwsem leak in crypto_user

* 'for-linus' of git://oss.sgi.com/xfs/xfs:
  xfs: fix force shutdown handling in xfs_end_io
  xfs: constify xfs_item_ops
  xfs: Fix possible memory corruption in xfs_readlink