For i.mx platform, set ttctrl.ttha with non-zero value only affects
sitd, and ehci core makes sure the schedule is not full when accepts
new request, so it will not occur the transaction which will acorss
the SoF.
Signed-off-by: Peter Chen <peter.chen@freescale.com>

The register of ttctrl.ttha describes like below:
- Internal TT Hub Address Representation
- RW
- Default = 0000000b
This field is used to match against the Hub Address field in QH & siTD
to determine if the packet is routed to the internal TT for directly
attached FS/LS devices. If the Hub Address in the QH or siTD does not
match this address then the packet will be broadcast on the High Speed
ports destined for a downstream High Speed hub with the address in the QH/siTD.

In silicon RTL, this entry only affects QH and siTD, and the hub.addr at
both QH and siTD are 0 in ehci core for chipidea (with hcd->has_tt = 1).

So, for QH, if the "usage_tt" flag at RTL is 0, set CI_HDRC_SET_NON_ZERO_TTHA
will not affect QH (with non-hs device); for siTD, set this flag
will change remaining space requirement for the last transaction from 1023
bytes to 188 bytes, it can increase the number of transactions within one
frame, ehci periodic schedule code will not queue the packet if the frame space
is full, so it is safe to set this flag for siTD.

With this flag, it can fix the problem Alan Stern reported below:
http://www.spinics.net/lists/linux-usb/msg123125.html
And may fix Michael Tessier's problem too.
http://www.spinics.net/lists/linux-usb/msg118679.html

CC: stern@rowland.harvard.edu
CC: michael.tessier@axiontech.ca
Signed-off-by: Peter Chen <peter.chen@freescale.com>

We want the USB fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull input subsystem fixes from Dmitry Torokhov:
 "Just small ALPS and Elan touchpads, and other driver fixups"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: elantech - add special check for fw_version 0x470f01 touchpad
  Input: twl4030-vibra - fix ERROR: Bad of_node_put() warning
  Input: alps - only Dell laptops have separate button bits for v2 dualpoint sticks
  Input: axp20x-pek - add module alias
  Input: turbografx - fix potential out of bound access

Pull MIPS fixes from Ralf Baechle:
 "Another round of MIPS fixes for 4.2.  No area does particularly stand
  out but we have a two unpleasant ones:

   - Kernel ptes are marked with a global bit which allows the kernel to
     share kernel TLB entries between all processes.  For this to work
     both entries of an adjacent even/odd pte pair need to have the
     global bit set.  There has been a subtle race in setting the other
     entry's global bit since ~ 2000 but it take particularly
     pathological workloads that essentially do mostly vmalloc/vfree to
     trigger this.

     This pull request fixes the 64-bit case but leaves the case of 32
     bit CPUs with 64 bit ptes unsolved for now.  The unfixed cases
     affect hardware that is not available in the field yet.

   - Instruction emulation requires loading instructions from user space
     but the current fast but simplistic approach will fail on pages
     that are PROT_EXEC but !PROT_READ.  For this reason we temporarily
     do not permit this permission and will map pages with PROT_EXEC |
     PROT_READ.

  The remainder of this pull request is more or less across the field
  and the short log explains them well"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: Make set_pte() SMP safe.
  MIPS: Replace add and sub instructions in relocate_kernel.S with addiu
  MIPS: Flush RPS on kernel entry with EVA
  Revert "MIPS: BCM63xx: Provide a plat_post_dma_flush hook"
  MIPS: BMIPS: Delete unused Kconfig symbol
  MIPS: Export get_c0_perfcount_int()
  MIPS: show_stack: Fix stack trace with EVA
  MIPS: do_mcheck: Fix kernel code dump with EVA
  MIPS: SMP: Don't increment irq_count multiple times for call function IPIs
  MIPS: Partially disable RIXI support.
  MIPS: Handle page faults of executable but unreadable pages correctly.
  MIPS: Malta: Don't reinitialise RTC
  MIPS: unaligned: Fix build error on big endian R6 kernels
  MIPS: Fix sched_getaffinity with MT FPAFF enabled
  MIPS: Fix build with CONFIG_OF=y for non OF-enabled targets
  CPUFREQ: Loongson2: Fix broken build due to incorrect include.

Pull btrfs fix from Chris Mason:
 "We have a btrfs quota regression fix.

  I merged this one on Thursday and have run it through tests against
  current master.

  Normally I wouldn't have sent this while you were finalizing rc6, but
  I'm feeding mosquitoes in the adirondacks next week, so I wanted to
  get this one out before leaving.  I'll leave longer tests running and
  check on things during the week, but I don't expect any problems"

* 'for-linus-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  btrfs: qgroup: Fix a regression in qgroup reserved space.

Pull thermal management fixes from Zhang Rui:
 "Specifics:

   - fix an error that "weight_attr" sysfs attribute is not removed
     while unbinding.  From: Viresh Kumar.

   - fix power allocator governor tracing to return the real request.
     From Javi Merino.

   - remove redundant owner assignment of hisi platform thermal driver.
     From Krzysztof Kozlowski.

   - a couple of small fixes of Exynos thermal driver.  From Krzysztof
     Kozlowski and Chanwoo Choi"

* 'for-rc' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux:
  thermal: Drop owner assignment from platform_driver
  thermal: exynos: Remove unused code related to platform_data on probe()
  thermal: exynos: Add the dependency of CONFIG_THERMAL_OF instead of CONFIG_OF
  thermal: exynos: Disable the regulator on probe failure
  thermal: power_allocator: trace the real requested power
  thermal: remove dangling 'weight_attr' device file

>From the usb 3.1 spec available at http://www.usb.org/developers/docs/
table 10-7 (Hub Class Requests) specifies the values for SetHubDepth and
GetPortErrorCount as:

Request			bmRequestType	bRequest		wValue		wIndex	wLength	Data
SetHubDepth		00100000B	SET_HUB_DEPTH		Hub Depth	Zero	Zero	None
GetPortErrorCount	10100011B	GET_PORT_ERR_COUNT	Zero		Port	Two	Number of Link Errors on this port

Fix these two values to match the spec.
Signed-off-by: Tal Shorer <tal.shorer@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Removed some checkpatch.pl warnings saying there was an unwanted space between
function names and their arguments.
Signed-off-by: Chase Metzger <chasemetzger15@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix two occurrences of the checkpatch.pl error:

ERROR: space prohibited before that ',' (ctx:WxW)

Fix one occurrence of the checkpatch error:

ERROR: space required before the open parenthesis '('
Signed-off-by: Kris Borer <kborer@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch enables xhci driver to support SPC by handling
Stopped - Short Packet event in transfer event path.

If SPC = '1' and the stop endpoint command is executed, after a Short
Packet condition has been detected, but before the end of the TD has been
reached, (i.e. the TD is in progress for pipe), then a Transfer Event TRB
with its Completion Code set to Stopped - Short Packet and its TRB
Transfer Length set to value of the EDTLA shall be forced for the
interrupted TRB, irrespective of whether its IOC or ISP flags are set.
This Transfer Event TRB will precede the Command Completion Event TRB for
the command, and is referred to as a Stopped Transfer Event.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

If the Contiguous Frame ID Capability is supported (CFC = 1),
then the xHC shall match the Frame ID in every Isoch TD with
SIA = 0 against the Frame Index of the MFINDEX register. This
rule ensures resynchronization of Isoch TDs even if some are
dropped due to Missed Service Errors or Stopping the endpoint.

This patch enables xHCI driver to support CFC by calculating
and setting the Frame ID field of an Isoch TRB.

[made some dbg messages checkpatch friendly -Mathias]
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This commit checks for the URB_ZERO_PACKET flag and creates an extra
zero-length td if the urb transfer length is a multiple of the endpoint's
max packet length.
Signed-off-by: Reyad Attiyat <reyad.attiyat@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Right now xhci-plat-hcd can be built when using one of platform specific
drivers only (mvebu/rcar). There shouldn't be such limitation as some
platforms may not require any quirks and may want to just use a generic
driver ("generic-xhci" / "xhci-hcd").
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull ARC fixes from Vineet Gupta:
 "Here's a late pull request for accumulated ARC fixes which came out of
  extended testing of the new ARCv2 port with LTP etc.  llock/scond
  livelock workaround has been reviewed by PeterZ.  The changes look a
  lot but I've crafted them into finer grained patches for better
  tracking later.

  I have some more fixes (ARC Futex backend) ready to go but those will
  have to wait for tglx to return from vacation.

  Summary:
   - Enable a reduced config of HS38 (w/o div-rem, ll64...)
   - Add software workaround for LLOCK/SCOND livelock
   - Fallout of a recent pt_regs update"

* tag 'arc-v4.2-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARCv2: spinlock/rwlock/atomics: reduce 1 instruction in exponential backoff
  ARC: Make pt_regs regs unsigned
  ARCv2: spinlock/rwlock: Reset retry delay when starting a new spin-wait cycle
  ARCv2: spinlock/rwlock/atomics: Delayed retry of failed SCOND with exponential backoff
  ARC: LLOCK/SCOND based rwlock
  ARC: LLOCK/SCOND based spin_lock
  ARC: refactor atomic inline asm operands with symbolic names
  Revert "ARCv2: STAR 9000837815 workaround hardware exclusive transactions livelock"
  ARCv2: [axs103_smp] Reduce clk for Quad FPGA configs
  ARCv2: Fix the peripheral address space detection
  ARCv2: allow selection of page size for MMUv4
  ARCv2: lib: memset: Don't assume 64-bit load/stores
  ARCv2: lib: memcpy: Missing PREFETCHW
  ARCv2: add knob for DIV_REV in Kconfig
  ARC/time: Migrate to new 'set-state' interface

Pull virtio fix from Michael Tsirkin:
 "A last minute fix for the new virtio input driver.  It seems pretty
   obvious, and the problem it's fixing would be quite hard to debug"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio-input: reset device and detach unused during remove

Pull device mapper fixes from Mike Snitzer:

 - stable fix for a dm_merge_bvec() regression on 32 bit Fedora systems.

 - fix for a 4.2 DM thinp discard regression due to inability to
   properly delete a range of blocks in a data mapping btree.

* tag 'dm-4.2-fixes-4' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm btree remove: fix bug in remove_one()
  dm: fix dm_merge_bvec regression on 32 bit systems

Pull sound fixes from Takashi Iwai:
 "The only bulk changes in this request is ABI updates for ASoC topology
  API.  It's a new API that was introduced in 4.2, and we'd like to
  avoid ABI change after the release, so it's taken now.  As there is no
  real in-tree user for this API, it should be fairly safe.

  Other than that, the usual small fixes are found in various drivers:
  ASoC cs4265, rt5645, intel-sst, firewire, oxygen and HD-audio"

* tag 'sound-4.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ASoC: topology: Add private data type and bump ABI version to 3
  ASoC: topology: Add ops support to byte controls UAPI
  ASoC: topology: Update TLV support so we can support more TLV types
  ASoC: topology: add private data to manifest
  ASoC: topology: Add subsequence in topology
  ALSA: hda - one Dell machine needs the headphone white noise fixup
  ALSA: fireworks/firewire-lib: add support for recent firmware quirk
  Revert "ALSA: fireworks: add support for AudioFire2 quirk"
  ASoC: topology: fix typo in soc_tplg_kcontrol_bind_io()
  ALSA: HDA: Dont check return for snd_hdac_chip_readl
  ALSA: HDA: Fix stream assignment for host in decoupled mode
  ASoC: rt5645: Fix lost pin setting for DMIC1
  ALSA: oxygen: Fix logical-not-parentheses warning
  ASoC: Intel: sst_byt: fix initialize 'NULL device *' issue
  ASoC: Intel: haswell: fix initialize 'NULL device *' issue
  ASoC: cs4265: Fix setting dai format for Left/Right Justified

Merge tag 'hwmon-for-linus-v4.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon fixes from Guenter Roeck:

 - Export module alias information in g762 and nct7904 to support
   auto-loading.

 - Blacklist Dell Studio XPS 8100 in dell-smm to fix fan control
   problems.

* tag 'hwmon-for-linus-v4.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (g762) Export OF module alias information
  hwmon: (nct7904) Export I2C module alias information
  hwmon: (dell-smm) Blacklist Dell Studio XPS 8100

Pull USB fixes from Greg KH:
 "Here are some USB and PHY fixes for 4.2-rc6 that resolve some reported
  issues.

  All of these have been in the linux-next tree for a while, full
  details on the patches are in the shortlog below"

* tag 'usb-4.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  ARM: dts: dra7: Add syscon-pllreset syscon to SATA PHY
  drivers/usb: Delete XHCI command timer if necessary
  xhci: fix off by one error in TRB DMA address boundary check
  usb: udc: core: add device_del() call to error pathway
  phy: ti-pipe3: i783 workaround for SATA lockup after dpll unlock/relock
  phy-sun4i-usb: Add missing EXPORT_SYMBOL_GPL for sun4i_usb_phy_set_squelch_detect
  USB: sierra: add 1199:68AB device ID
  usb: gadget: f_printer: actually limit the number of instances
  usb: gadget: f_hid: actually limit the number of instances
  usb: gadget: f_uac2: fix calculation of uac2->p_interval
  usb: gadget: bdc: fix a driver crash on disconnect
  usb: chipidea: ehci_init_driver is intended to call one time
  USB: qcserial: Add support for Dell Wireless 5809e 4G Modem
  USB: qcserial/option: make AT URCs work for Sierra Wireless MC7305/MC7355

Pull staging driver fixes from Greg KH:
 "Here are three bugfixes for some staging driver issues that have been
  reported.  All have been in the linux-next tree for a while"

* tag 'staging-4.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: lustre: Include unaligned.h instead of access_ok.h
  staging: vt6655: vnt_bss_info_changed check conf->beacon_rate is not NULL
  staging: comedi: das1800: add missing break in switch

Pull char/misc fixes from Greg KH:
 "Here are some extcon fixes for 4.2-rc6 that resolve some reported
  problems.

  All have been in linux-next for a while"

* tag 'char-misc-4.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  extcon: Fix extcon_cable_get_state() from getting old state after notification
  extcon: Fix hang and extcon_get/set_cable_state().
  extcon: palmas: Fix NULL pointer error

Pull drm fixes from Daniel Vetter:
 "One i915 regression fix and a drm core one since Dave's not around,
  both introduced in 4.2 so not cc: stable.

  The fix for the warning Ted reported isn't in here yet since he didn't
  yet supply a tested-by and I can't repro this one myself (it's in
  fixup code that needs firmware doing something i915 wouldn't do)"

* tag 'drm-intel-fixes-2015-08-07' of git://anongit.freedesktop.org/drm-intel:
  drm/vblank: Use u32 consistently for vblank counters
  drm/i915: Allow parsing of variable size child device entries from VBT

It is no need to check the packet[0] for sanity check when doing
elantech_packet_check_v4() function for fw_version = 0x470f01 touchpad.

Signed-off by: Duson Lin <dusonlin@emc.com.tw>
Reviewed-by: Ulrik De Bie <ulrik.debie-os@e2big.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

remove_one() was not incrementing the key for the beginning of the
range, so not all entries were being removed.  This resulted in
discards that were not unmapping all blocks.

Fixes: 4ec331c3 ("dm btree: add dm_btree_remove_leaves()")
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

In

commit 99264a61
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Wed Apr 15 19:34:43 2015 +0200

    drm/vblank: Fixup and document timestamp update/read barriers

I've switched vblank->count from atomic_t to unsigned long and
accidentally created an integer comparison bug in
drm_vblank_count_and_time since vblanke->count might overflow the u32
local copy and hence the retry loop never succeed.

Fix this by consistently using u32.

Cc: Michel Dänzer <michel@daenzer.net>
Reported-by: Michel Dänzer <michel@daenzer.net>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

Merge tag 'asoc-fix-v4.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v4.2

There are a couple of small driver specific fixes here but the
overwhelming bulk of these changes are fixes to the topology ABI that
has been newly introduced in v4.2.  Once this makes it into a release we
will have to firm this up but for now getting enhancements in before
they've made it into a release is the most expedient thing.

The increment of delay counter was 2 instructions:
Arithmatic Shfit Left (ASL) + set to 1 on overflow

This can be done in 1 using ROtate Left (ROL)
Suggested-by: Nigel Topham <ntopham@synopsys.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

Pull sparc fix from David Miller:
 "FPU register corruption bug fix"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
  sparc64: Fix userspace FPU register corruptions.

Merge fixes from Andrew Morton:
 "21 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (21 commits)
  writeback: fix initial dirty limit
  mm/memory-failure: set PageHWPoison before migrate_pages()
  mm: check __PG_HWPOISON separately from PAGE_FLAGS_CHECK_AT_*
  mm/memory-failure: give up error handling for non-tail-refcounted thp
  mm/memory-failure: fix race in counting num_poisoned_pages
  mm/memory-failure: unlock_page before put_page
  ipc: use private shmem or hugetlbfs inodes for shm segments.
  mm: initialize hotplugged pages as reserved
  ocfs2: fix shift left overflow
  kthread: export kthread functions
  fsnotify: fix oops in fsnotify_clear_marks_by_group_flags()
  lib/iommu-common.c: do not use 0xffffffffffffffffl for computing align_mask
  mm/slub: allow merging when SLAB_DEBUG_FREE is set
  signalfd: fix information leak in signalfd_copyinfo
  signal: fix information leak in copy_siginfo_to_user
  signal: fix information leak in copy_siginfo_from_user32
  ocfs2: fix BUG in ocfs2_downconvert_thread_do_work()
  fs, file table: reinit files_stat.max_files after deferred memory initialisation
  mm, meminit: replace rwsem with completion
  mm, meminit: allow early_pfn_to_nid to be used during runtime
  ...

If we have a series of events from userpsace, with %fprs=FPRS_FEF,
like follows:

ETRAP
	ETRAP
		VIS_ENTRY(fprs=0x4)
		VIS_EXIT
		RTRAP (kernel FPU restore with fpu_saved=0x4)
	RTRAP

We will not restore the user registers that were clobbered by the FPU
using kernel code in the inner-most trap.

Traps allocate FPU save slots in the thread struct, and FPU using
sequences save the "dirty" FPU registers only.

This works at the initial trap level because all of the registers
get recorded into the top-level FPU save area, and we'll return
to userspace with the FPU disabled so that any FPU use by the user
will take an FPU disabled trap wherein we'll load the registers
back up properly.

But this is not how trap returns from kernel to kernel operate.

The simplest fix for this bug is to always save all FPU register state
for anything other than the top-most FPU save area.

Getting rid of the optimized inner-slot FPU saving code ends up
making VISEntryHalf degenerate into plain VISEntry.

Longer term we need to do something smarter to reinstate the partial
save optimizations.  Perhaps the fundament error is having trap entry
and exit allocate FPU save slots and restore register state.  Instead,
the VISEntry et al. calls should be doing that work.

This bug is about two decades old.
Reported-by: James Y Knight <jyknight@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull amdgpu fixes from Alex Deucher:
 "Just a few amdgpu fixes to make sure we report the proper firmware
  information and number of render buffers to userspace and a typo in a
  debugging function"

[ Pulling directly from Alex since Dave Airlie is on vacation  - Linus ]

* 'drm-fixes-4.2' of git://people.freedesktop.org/~agd5f/linux:
  drm/amdgpu: set fw_version and feature_version for smu fw loading
  drm/amdgpu: add feature version for SDMA ucode
  drm/amdgpu: add feature version for RLC and MEC v2
  drm/amdgpu: increment queue when iterating on this variable.
  drm/amdgpu: fix rb setting for CZ

Pull TDA998x i2c driver fixes from Russell King:
 "This fixes the double-checksumming of the AVI infoframe which was
  resulting in the checksum always being zero.  It went unnoticed as
  none of my HDMI devices had a problem with this"

[ Pulling directly from rmk since Dave Airlie is on vacation  - Linus ]

* 'drm-tda998x-fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  drm/i2c: tda998x: fix bad checksum of the HDMI AVI infoframe

The initial value of global_wb_domain.dirty_limit set by
writeback_set_ratelimit() is zeroed out by the memset in
wb_domain_init().
Signed-off-by: Rabin Vincent <rabin.vincent@axis.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Now page freeing code doesn't consider PageHWPoison as a bad page, so by
setting it before completing the page containment, we can prevent the
error page from being reused just after successful page migration.

I added TTU_IGNORE_HWPOISON for try_to_unmap() to make sure that the
page table entry is transformed into migration entry, not to hwpoison
entry.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Dean Nelson <dnelson@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The race condition addressed in commit add05cec ("mm: soft-offline:
don't free target page in successful page migration") was not closed
completely, because that can happen not only for soft-offline, but also
for hard-offline.  Consider that a slab page is about to be freed into
buddy pool, and then an uncorrected memory error hits the page just
after entering __free_one_page(), then VM_BUG_ON_PAGE(page->flags &
PAGE_FLAGS_CHECK_AT_PREP) is triggered, despite the fact that it's not
necessary because the data on the affected page is not consumed.

To solve it, this patch drops __PG_HWPOISON from page flag checks at
allocation/free time.  I think it's justified because __PG_HWPOISON
flags is defined to prevent the page from being reused, and setting it
outside the page's alloc-free cycle is a designed behavior (not a bug.)

For recent months, I was annoyed about BUG_ON when soft-offlined page
remains on lru cache list for a while, which is avoided by calling
put_page() instead of putback_lru_page() in page migration's success
path.  This means that this patch reverts a major change from commit
add05cec about the new refcounting rule of soft-offlined pages, so
"reuse window" revives.  This will be closed by a subsequent patch.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Dean Nelson <dnelson@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

"non anonymous thp" case is still racy with freeing thp, which causes
panic due to put_page() for refcount-0 page.  It seems that closing up
this race might be hard (and/or not worth doing,) so let's give up the
error handling for this case.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Dean Nelson <dnelson@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When memory_failure() is called on a page which are just freed after
page migration from soft offlining, the counter num_poisoned_pages is
raised twi= ce.  So let's fix it with using TestSetPageHWPoison.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Dean Nelson <dnelson@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Recently I addressed a few of hwpoison race problems and the patches are
merged on v4.2-rc1.  It made progress, but unfortunately some problems
still remain due to less coverage of my testing.  So I'm trying to fix
or avoid them in this series.

One point I'm expecting to discuss is that patch 4/5 changes the page
flag set to be checked on free time.  In current behavior, __PG_HWPOISON
is not supposed to be set when the page is freed.  I think that there is
no strong reason for this behavior, and it causes a problem hard to fix
only in error handler side (because __PG_HWPOISON could be set at
arbitrary timing.) So I suggest to change it.

With this patchset, hwpoison stress testing in official mce-test
testsuite (which previously failed) passes.

This patch (of 5):

In "just unpoisoned" path, we do put_page and then unlock_page, which is
a wrong order and causes "freeing locked page" bug.  So let's fix it.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Dean Nelson <dnelson@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Hugh Dickins <hughd@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>