Needed in order to update the DM thinp code to use the new async
__blkdev_issue_discard() interface.

Commit 326e1dbb ("block: remove management of bi_remaining when
restoring original bi_end_io") made bio_inc_remaining() private to bio.c
because the only use-case that made sense was confined to the
bio_chain() interface.

Since that time DM thinp went on to use bio_chain() in its relatively
complex implementation of async discard support.  That implementation,
even when converted over to use the new async __blkdev_issue_discard()
interface, depends on deferred completion of the original discard bio --
which is most appropriately implemented using bio_inc_remaining().

DM thinp foolishly duplicated bio_inc_remaining(), local to dm-thin.c as
__bio_inc_remaining(), so re-exporting bio_inc_remaining() allows us to
put an end to that foolishness.

All said, bio_inc_remaining() should really only be used in conjunction
with bio_chain().  It isn't intended for generic bio reference counting.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Commit 38f25255 ("block: add __blkdev_issue_discard") incorrectly
disallowed the early return of -EOPNOTSUPP if the device doesn't support
discard (or secure discard).  This early return of -EOPNOTSUPP has
always been part of blkdev_issue_discard() interface so there isn't a
good reason to break that behaviour -- especially when it can be easily
reinstated.

The nuance of allowing early return of -EOPNOTSUPP vs disallowing late
return of -EOPNOTSUPP is: if the overall device never advertised support
for discards and one is issued to the device it is beneficial to inform
the caller that discards are not supported via -EOPNOTSUPP.  But if a
device advertises discard support it means that at least a subset of the
device does have discard support -- but it could be that discards issued
to some regions of a stacked device will not be supported.  In that case
the late return of -EOPNOTSUPP must be disallowed.

Fixes: 38f25255 ("block: add __blkdev_issue_discard")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

blk_account_io_start does not need to be wrapped with blk_do_io_stat
ais it already checks for that condition.
Signed-off-by: Michael Callahan <michaelcallahan@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

This is a version of blkdev_issue_discard which doesn't wait for
the I/O to complete, but instead allows the caller to submit
the final bio and/or chain it to others.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Sagi Grimberg <sagig@grimberg.me>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

It can be replaced with a combination of bio_chain and submit_bio_wait.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Sagi Grimberg <sagig@grimberg.me>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Pull thermal fixes from Eduardo Valentin:
 "A couple of minor fixes for the thermal subsystem.

  Specifics in this pull request:

   - Fixes in hisilicon thermal driver
   - More fixes of unsigned to int type change in thermal_core.c"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/evalenti/linux-soc-thermal:
  thermal: use %d to print S32 parameters
  thermal: hisilicon: increase temperature resolution

Pull powerpc fixes from Michael Ellerman:
 "A few more powerpc fixes for 4.6:

   - cxl: Keep IRQ mappings on context teardown from Michael Neuling

   - cxl: Poll for outstanding IRQs when detaching a context from
     Michael Neuling

   - Wire up preadv2 and pwritev2 syscalls from Rui Salvaterra"

* tag 'powerpc-4.6-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc: wire up preadv2 and pwritev2 syscalls
  cxl: Poll for outstanding IRQs when detaching a context
  cxl: Keep IRQ mappings on context teardown

Pull EDAC fix from Borislav Petkov:
 "Make sure sb_edac and i7core_edac do not terminate MCE processing on
  the decoding callchain prematurely"

* tag 'edac_fix_for_4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp:
  EDAC: i7core, sb_edac: Don't return NOTIFY_BAD from mce_decoder callback

Pull power management fixes from Rafael Wysocki:
 "One revert of a recent cpufreq commit that introduced a regression and
  a fix for intel_pstate's Turbo Activation Ratio handling code.

  Specifics:

   - Revert cpufreq commit that attempted to fix a problem in the
     ondemand/conservative governor code, but did that incorrectly and
     introduced another problem instead (Rafael Wysocki).

   - Fix incorrect decoding of MSR contents related to the Turbo
     Activation Ratio (TAR) handling in the intel_pstate driver
     (Srinivas Pandruvada)"

* tag 'pm+acpi-4.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: intel_pstate: Fix processing for turbo activation ratio
  Revert "cpufreq: governor: Fix negative idle_time when configured with CONFIG_HZ_PERIODIC"

Pull MMC fixes from Ulf Hansson:
 "Here are a two MMC host fixes:

  - sdhci-acpi: Reduce Baytrail eMMC/SD/SDIO hangs

  - sunxi: Disable eMMC HS-DDR for Allwinner A80"

* tag 'mmc-v4.6-rc4' of git://git.linaro.org/people/ulf.hansson/mmc:
  mmc: sunxi: Disable eMMC HS-DDR (MMC_CAP_1_8V_DDR) for Allwinner A80
  mmc: sdhci-acpi: Reduce Baytrail eMMC/SD/SDIO hangs

Pull drm fixes from Dave Airlie:
 "A few fixes all over the place:

  radeon is probably the biggest standout, it's a fix for screen
  corruption or hung black outputs so I thought it was worth pulling in.

  Otherwise some amdgpu power control fixes, some misc vmwgfx fixes, one
  etnaviv fix, one virtio-gpu fix, two DP MST fixes, and a single TTM
  fix"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/vmwgfx: Fix order of operation
  drm/vmwgfx: use vmw_cmd_dx_cid_check for query commands.
  drm/vmwgfx: Enable SVGA_3D_CMD_DX_SET_PREDICATION
  drm/amdgpu: disable vm interrupts with vm_fault_stop=2
  drm/amdgpu: print a message if ATPX dGPU power control is missing
  Revert "drm/amdgpu: disable runtime pm on PX laptops without dGPU power control"
  drm/radeon: fix vertical bars appear on monitor (v2)
  drm/ttm: fix kref count mess in ttm_bo_move_to_lru_tail
  drm/virtio: send vblank event after crtc updates
  drm/dp/mst: Restore primary hub guid on resume
  drm/dp/mst: Get validated port ref in drm_dp_update_payload_part1()
  drm/etnaviv: don't move linear memory window on 3D cores without MC2.0

Pull rdma fixes from Doug Ledford:
 "Final set of -rc fixes for 4.6.

  I've collected up a number of patches that are all pretty small with
  the exception of only a couple.  The hfi1 driver has a number of
  important patches, and it is what really drives the line count of this
  pull request up.  These are all small and I've got this kernel built
  and running in the test lab (I have most of the hardware, I think nes
  is the only thing in this patch set that I can't say I've personally
  tested and have up and running).

  Summary:

   - A number of collected fixes for oopses, memory corruptions,
     deadlocks, etc.  All of these fixes are small (many only 5-10
     lines), obvious, and tested.

   - Fix for the security issue related to the use of write for
     bi-directional communications"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma:
  RDMA/nes: don't leak skb if carrier down
  IB/security: Restrict use of the write() interface
  IB/hfi1: Use kernel default llseek for ui device
  IB/hfi1: Don't attempt to free resources if initialization failed
  IB/hfi1: Fix missing lock/unlock in verbs drain callback
  IB/rdmavt: Fix send scheduling
  IB/hfi1: Prevent unpinning of wrong pages
  IB/hfi1: Fix deadlock caused by locking with wrong scope
  IB/hfi1: Prevent NULL pointer deferences in caching code
  MAINTAINERS: Update iser/isert maintainer contact info
  IB/mlx5: Expose correct max_sge_rd limit
  RDMA/iw_cxgb4: Fix bar2 virt addr calculation for T4 chips
  iw_cxgb4: handle draining an idle qp
  iw_cxgb3: initialize ibdev.iwcm->ifname for port mapping
  iw_cxgb4: initialize ibdev.iwcm->ifname for port mapping
  IB/core: Don't drain non-existent rq queue-pair
  IB/core: Fix oops in ib_cache_gid_set_default_gid

Merge fixes from Andrew Morton:
 "20 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  Documentation/sysctl/vm.txt: update numa_zonelist_order description
  lib/stackdepot.c: allow the stack trace hash to be zero
  rapidio: fix potential NULL pointer dereference
  mm/memory-failure: fix race with compound page split/merge
  ocfs2/dlm: return zero if deref_done message is successfully handled
  Ananth has moved
  kcov: don't profile branches in kcov
  kcov: don't trace the code coverage code
  mm: wake kcompactd before kswapd's short sleep
  .mailmap: add Frank Rowand
  mm/hwpoison: fix wrong num_poisoned_pages accounting
  mm: call swap_slot_free_notify() with page lock held
  mm: vmscan: reclaim highmem zone if buffer_heads is over limit
  numa: fix /proc/<pid>/numa_maps for THP
  mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA check
  mailmap: fix Krzysztof Kozlowski's misspelled name
  thp: keep huge zero page pinned until tlb flush
  mm: exclude HugeTLB pages from THP page_mapped() logic
  kexec: export OFFSET(page.compound_head) to find out compound tail page
  kexec: update VMCOREINFO for compound_order/dtor

Both of these drivers can return NOTIFY_BAD, but this terminates
processing other callbacks that were registered later on the chain.
Since the driver did nothing to log the error it seems wrong to prevent
other interested parties from seeing it. E.g. neither of them had even
bothered to check the type of the error to see if it was a memory error
before the return NOTIFY_BAD.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Acked-by: Aristeu Rozanski <aris@redhat.com>
Acked-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/72937355dd92318d2630979666063f8a2853495b.1461864507.git.tony.luck@intel.comSigned-off-by: Borislav Petkov <bp@suse.de>

* pm-cpufreq-fixes:
  cpufreq: intel_pstate: Fix processing for turbo activation ratio
  Revert "cpufreq: governor: Fix negative idle_time when configured with CONFIG_HZ_PERIODIC"

A few fixes for 4.6.
- revert amdgpu PX commit that was previously reverted on the radeon side
- cleaned up version of the NI+ MC update display fix for radeon
- TTM kref fix

* 'drm-fixes-4.6' of git://people.freedesktop.org/~agd5f/linux:
  drm/amdgpu: disable vm interrupts with vm_fault_stop=2
  drm/amdgpu: print a message if ATPX dGPU power control is missing
  Revert "drm/amdgpu: disable runtime pm on PX laptops without dGPU power control"
  drm/radeon: fix vertical bars appear on monitor (v2)
  drm/ttm: fix kref count mess in ttm_bo_move_to_lru_tail

three misc vmwgfx fixes

* 'drm-vmwgfx-fixes' of git://people.freedesktop.org/~syeh/repos_linux:
  drm/vmwgfx: Fix order of operation
  drm/vmwgfx: use vmw_cmd_dx_cid_check for query commands.
  drm/vmwgfx: Enable SVGA_3D_CMD_DX_SET_PREDICATION

Pull x86 fixes from Ingo Molnar:
 "Two boot crash fixes and an IRQ handling crash fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/apic: Handle zero vector gracefully in clear_vector_irq()
  Revert "x86/mm/32: Set NX in __supported_pte_mask before enabling paging"
  xen/qspinlock: Don't kick CPU if IRQ is not initialized

Pull perf fixes from Ingo Molnar:
 "x86 PMU driver fixes plus a core code race fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel: Fix incorrect lbr_sel_mask value
  perf/x86/intel/pt: Don't die on VMXON
  perf/core: Fix perf_event_open() vs. execve() race
  perf/x86/amd: Set the size of event map array to PERF_COUNT_HW_MAX
  perf/core: Make sysctl_perf_cpu_time_max_percent conform to documentation
  perf/x86/intel/rapl: Add missing Haswell model
  perf/x86/intel: Add model number for Skylake Server to perf

Pull locking fixes from Ingo Molnar:
 "Two lockdep fixes"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  lockdep: Fix lock_chain::base size
  locking/lockdep: Fix ->irq_context calculation

Pull EFI fix from Ingo Molnar:
 "This fixes a bug in the efivars code"

* 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi: Fix out-of-bounds read in variable_matches()

Pull media fixes from Mauro Carvalho Chehab:
 "Some regression fixes:

   - videobuf2 core: avoid the risk of going past buffer on multi-planes
     and fix rw mode

   - fix support for 4K formats at V4L2 core

   - fix a trouble at davinci_fpe, caused by a bad patch

   - usbvision: revert a patch with a partial fixup.  The fixup patch
     was merged already, and this one has some issues"

* tag 'media/v4.6-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
  [media] vb2-memops: Fix over allocation of frame vectors
  [media] media: vb2: Fix regression on poll() for RW mode
  [media] v4l2-dv-timings.h: fix polarity for 4k formats
  [media] davinci_vpfe: Revert "staging: media: davinci_vpfe: remove,unnecessary ret variable"
  [media] usbvision: revert commit 588afcc1
  [media] videobuf2-v4l2: Verify planes array in buffer dequeueing
  [media] videobuf2-core: Check user space planes array in dqbuf

Pull sound fixes from Takashi Iwai:
 "Usually we get a big collection of fixes for ASoC once during rc.  And
  this is it.

  At this time, most of fixes are about Intel Skylake ASoC driver, which
  is a new and still on-going development.  Along with it, a slight
  large LOC is seen in legacy HD-audio driver, but it's merely a code
  move to the upper layer.

  Other than that, the rest are small or trivial fixes to various
  drivers, in addition to an ASoC dapm debugfs code fix"

* tag 'sound-4.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (24 commits)
  ALSA: hda - Update BCLK also at hotplug for i915 HSW/BDW
  ALSA: hda - Add dock support for ThinkPad X260
  ASoC: wm5102: Free compressed IRQ in CODEC remove
  ASoC: arizona: Free speaker thermal IRQs in CODEC remove
  ASoC: Intel: Skylake: Fix ibs/obs calc for non-integral sampling rates
  ASoC: Intel: sst: fix a loop timeout in sst_hsw_stream_reset()
  ASoC: Intel: Skylake: Fix to turn OFF codec power when entering S3
  ASoC: hdac_hdmi: Fix codec power state in S3 during playback
  ASoC: hdac_hdmi: Fix to use dev_pm ops instead soc pm
  ASoC: wm8962: Correct typo when setting DSPCLK rate
  ASoC: nau8825: Fix jack detection across suspend
  ASoC: Intel: Skylake: Fix DSP resource de-allocation
  ASoC: Intel: Skylake: Fix for unloading module only when it is loaded
  ASoC: Intel: Skylake: Fix kbuild dependency
  ASoC: dapm: Make sure we have a card when displaying component widgets
  ASoC: rt5640: Correct the digital interface data select
  ASoC: Intel: Skylake: remove call to pci_dev_put
  ASoC: Intel: Skylake: Call i915 exit last
  ASoC: Intel: Skylake: Unmap the address last
  ASoC: Intel: Skylake: Freeup properly on skl_dsp_free
  ...

Commit 3193913c ("mm: page_alloc: default node-ordering on 64-bit
NUMA, zone-ordering on 32-bit") changes the default value of
numa_zonelist_order.  Update the document.
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Do not bail out from depot_save_stack() if the stack trace has zero hash.
Initially depot_save_stack() silently dropped stack traces with zero
hashes, however there's actually no point in reserving this zero value.
Reported-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The change fixes improper check for a returned error value by
class_create() function, which on error returns ERR_PTR() value, thus the
original check always results in a dead code on error path.
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

get_hwpoison_page() must recheck relation between head and tail pages.

n-horiguchi said: without this recheck, the race causes kernel to pin an
irrelevant page, and finally makes kernel crash for refcount mismatch.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

dlm_deref_lockres_done_handler() should return zero if the message is
successfully handled.

Fixes: 60d663cb ("ocfs2/dlm: add DEREF_DONE message").
Signed-off-by: xuejiufei <xuejiufei@huawei.com>
Reviewed-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The current ID is going away soon... update email address
Signed-off-by: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Profiling 'if' statements in __sanitizer_cov_trace_pc() leads to
unbound recursion and crash:

	__sanitizer_cov_trace_pc() ->
		ftrace_likely_update ->
			__sanitizer_cov_trace_pc() ...

Define DISABLE_BRANCH_PROFILING to disable this tracer.
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Kcov causes the compiler to add a call to __sanitizer_cov_trace_pc() in
every basic block.  Ftrace patches in a call to _mcount() to each
function it has annotated.

Letting these mechanisms annotate each other is a bad thing.  Break the
loop by adding 'notrace' to __sanitizer_cov_trace_pc() so that ftrace
won't try to patch this code.

This patch lets arm64 with KCOV and STACK_TRACER boot.
Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When kswapd goes to sleep it checks if the node is balanced and at first
it sleeps only for HZ/10 time, then rechecks if the node is still
balanced and nobody has woken it during the initial sleep.  Only then it
goes fully sleep until an allocation slowpath wakes it up again.

For higher-order allocations, waking up kcompactd is done only before
the full sleep.  This turns out to be an issue in case another
high-order allocation fails during the initial sleep.  It will wake
kswapd up, however kswapd considers the zone balanced from the order-0
perspective, and will just quickly try to sleep again.  So if there's a
longer stream of high-order allocations hitting the slowpath and waking
up kswapd, it might never actually wake up kcompactd, which may be
considered a regression from kswapd-based compaction.  In the worst
case, it might be that a single allocation that cannot direct
reclaim/compact itself is waking kswapd in the retry loop and preventing
kcompactd from being woken up and unblocking it.

This patch makes sure kcompactd is woken up in such situations by simply
moving the wakeup before the short initial sleep.  More efficient
solution would be to wake kcompactd immediately instead of kswapd if the
node is already order-0 balanced, but in that case we should also move
reset_isolation_suitable() call to kcompactd so it's not adding to the
allocator's latency.  Since it's late in the 4.6 cycle, let's go with
the simpler change for now.

Fixes: accf6242 ("mm, kswapd: replace kswapd compaction with waking up kcompactd")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Set current email address to replace obsolete email addresses.
Signed-off-by: Frank Rowand <frank.rowand@sonymobile.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Currently, migration code increses num_poisoned_pages on *failed*
migration page as well as successfully migrated one at the trial of
memory-failure.  It will make the stat wrong.  As well, it marks the
page as PG_HWPoison even if the migration trial failed.  It would mean
we cannot recover the corrupted page using memory-failure facility.

This patches fixes it.
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Kyeongdon reported below error which is BUG_ON(!PageSwapCache(page)) in
page_swap_info.  The reason is that page_endio in rw_page unlocks the
page if read I/O is completed so we need to hold a PG_lock again to
check PageSwapCache.  Otherwise, the page can be removed from swapcache.

  Kernel BUG at c00f9040 [verbose debug info unavailable]
  Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
  Modules linked in:
  CPU: 4 PID: 13446 Comm: RenderThread Tainted: G        W 3.10.84-g9f14aec-dirty #73
  task: c3b73200 ti: dd192000 task.ti: dd192000
  PC is at page_swap_info+0x10/0x2c
  LR is at swap_slot_free_notify+0x18/0x6c
  pc : [<c00f9040>]    lr : [<c00f5560>]    psr: 400f0113
  sp : dd193d78  ip : c2deb1e4  fp : da015180
  r10: 00000000  r9 : 000200da  r8 : c120fe08
  r7 : 00000000  r6 : 00000000  r5 : c249a6c0  r4 : = c249a6c0
  r3 : 00000000  r2 : 40080009  r1 : 200f0113  r0 : = c249a6c0
  ..<snip> ..
  Call Trace:
    page_swap_info+0x10/0x2c
    swap_slot_free_notify+0x18/0x6c
    swap_readpage+0x90/0x11c
    read_swap_cache_async+0x134/0x1ac
    swapin_readahead+0x70/0xb0
    handle_pte_fault+0x320/0x6fc
    handle_mm_fault+0xc0/0xf0
    do_page_fault+0x11c/0x36c
    do_DataAbort+0x34/0x118

Fixes: 3f2b1a04 ("zram: revive swap_slot_free_notify")
Signed-off-by: Minchan Kim <minchan@kernel.org>
Tested-by: Kyeongdon Kim <kyeongdon.kim@lge.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We have been reclaimed highmem zone if buffer_heads is over limit but
commit 6b4f7799 ("mm: vmscan: invoke slab shrinkers from
shrink_zone()") changed the behavior so it doesn't reclaim highmem zone
although buffer_heads is over the limit.  This patch restores the logic.

Fixes: 6b4f7799 ("mm: vmscan: invoke slab shrinkers from shrink_zone()")
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In gather_pte_stats() a THP pmd is cast into a pte, which is wrong
because the layouts may differ depending on the architecture.  On s390
this will lead to inaccurate numa_maps accounting in /proc because of
misguided pte_present() and pte_dirty() checks on the fake pte.

On other architectures pte_present() and pte_dirty() may work by chance,
but there may be an issue with direct-access (dax) mappings w/o
underlying struct pages when HAVE_PTE_SPECIAL is set and THP is
available.  In vm_normal_page() the fake pte will be checked with
pte_special() and because there is no "special" bit in a pmd, this will
always return false and the VM_PFNMAP | VM_MIXEDMAP checking will be
skipped.  On dax mappings w/o struct pages, an invalid struct page
pointer would then be returned that can crash the kernel.

This patch fixes the numa_maps THP handling by introducing new "_pmd"
variants of the can_gather_numa_stats() and vm_normal_page() functions.
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org>	[4.3+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Khugepaged detects own VMAs by checking vm_file and vm_ops but this way
it cannot distinguish private /dev/zero mappings from other special
mappings like /dev/hpet which has no vm_ops and popultes PTEs in mmap.

This fixes false-positive VM_BUG_ON and prevents installing THP where
they are not expected.

Link: http://lkml.kernel.org/r/CACT4Y+ZmuZMV5CjSFOeXviwQdABAgT7T+StKfTqan9YDtgEi5g@mail.gmail.com
Fixes: 78f11a25 ("mm: thp: fix /dev/zero MAP_PRIVATE and vm_flags cleanups")
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>