We might need to do some actions before the shadow variable is freed.
For example, we might need to remove it from a list or free some data
that it points to.

This is already possible now. The user can get the shadow variable
by klp_shadow_get(), do the necessary actions, and then call
klp_shadow_free().

This patch allows to do it a more elegant way. The user could implement
the needed actions in a callback that is passed to klp_shadow_free()
as a parameter. The callback usually does reverse operations to
the constructor callback that can be called by klp_shadow_*alloc().

It is especially useful for klp_shadow_free_all(). There we need to do
these extra actions for each found shadow variable with the given ID.

Note that the memory used by the shadow variable itself is still released
later by rcu callback. It is needed to protect internal structures that
keep all shadow variables. But the destructor is called immediately.
The shadow variable must not be access anyway after klp_shadow_free()
is called. The user is responsible to protect this any suitable way.

Be aware that the destructor is called under klp_shadow_lock. It is
the same as for the contructor in klp_shadow_alloc().
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

The existing API allows to pass a sample data to initialize the shadow
data. It works well when the data are position independent. But it fails
miserably when we need to set a pointer to the shadow structure itself.

Unfortunately, we might need to initialize the pointer surprisingly
often because of struct list_head. It is even worse because the list
might be hidden in other common structures, for example, struct mutex,
struct wait_queue_head.

For example, this was needed to fix races in ALSA sequencer. It required
to add mutex into struct snd_seq_client. See commit b3defb79
("ALSA: seq: Make ioctls race-free") and commit d15d662e
("ALSA: seq: Fix racy pool initializations")

This patch makes the API more safe. A custom constructor function and data
are passed to klp_shadow_*alloc() functions instead of the sample data.

Note that ctor_data are no longer a template for shadow->data. It might
point to any data that might be necessary when the constructor is called.

Also note that the constructor is called under klp_shadow_lock. It is
an internal spin_lock that synchronizes alloc() vs. get() operations,
see klp_shadow_get_or_alloc(). On one hand, this adds a risk of ABBA
deadlocks. On the other hand, it allows to do some operations safely.
For example, we could add the new structure into an existing list.
This must be done only once when the structure is allocated.
Reported-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Pull livepatching updates from Jiri Kosina:

 - handle 'infinitely'-long sleeping tasks, from Miroslav Benes

 - remove 'immediate' feature, as it turns out it doesn't provide the
   originally expected semantics, and brings more issues than value

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
  livepatch: add locking to force and signal functions
  livepatch: Remove immediate feature
  livepatch: force transition to finish
  livepatch: send a fake signal to all blocking tasks

Pull HID updates from Jiri Kosina:

 - remove hid_have_special_driver[] entry hard requirement for any newly
   supported VID/PID by a specific non-core hid driver, and general
   related cleanup of HID matching core, from Benjamin Tissoires

 - support for new Wacom devices and a few small fixups for already
   supported ones in Wacom driver, from Aaron Armstrong Skomra and Jason
   Gerecke

 - sysfs interface fix for roccat driver from Dan Carpenter

 - support for new Asus HW (T100TAF, T100HA, T200TA) from Hans de Goede

 - improved support for Jabra devices, from Niels Skou Olsen

 - other assorted small fixes and new device IDs

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid: (30 commits)
  HID: quirks: Fix keyboard + touchpad on Toshiba Click Mini not working
  HID: roccat: prevent an out of bounds read in kovaplus_profile_activated()
  HID: asus: Fix special function keys on T200TA
  HID: asus: Add touchpad max x/y and resolution info for the T200TA
  HID: wacom: Add support for One by Wacom (CTL-472 / CTL-672)
  HID: wacom: Fix reporting of touch toggle (WACOM_HID_WD_MUTE_DEVICE) events
  HID: intel-ish-hid: Enable Cannon Lake and Coffee Lake laptop/desktop
  HID: elecom: rewrite report fixup for EX-G and future mice
  HID: sony: Report DS4 version info through sysfs
  HID: sony: Print reversed MAC address via %pMR
  HID: wacom: EKR: ensure devres groups at higher indexes are released
  HID: rmi: Support the Fujitsu R726 Pad dock using hid-rmi
  HID: add quirk for another PIXART OEM mouse used by HP
  HID: quirks: make array hid_quirks static
  HID: hid-multitouch: support fine-grain orientation reporting
  HID: asus: Add product-id for the T100TAF and T100HA keyboard docks
  HID: elo: clear BTN_LEFT mapping
  HID: multitouch: Combine all left-button events in a frame
  HID: multitouch: Only look at non touch fields in first packet of a frame
  HID: multitouch: Properly deal with Win8 PTP reports with 0 touches
  ...

Pull IPMI updates from Corey Minyard:
 "Small fixes for various things, been sitting in next for a while (some
  a long time)"

* tag 'for-linus-4.16-1' of git://github.com/cminyard/linux-ipmi:
  ipmi_ssif: Remove duplicate NULL check
  ipmi/powernv: Fix error return code in ipmi_powernv_probe()
  ipmi: use dynamic memory for DMI driver override
  ipmi/ipmi_powernv: remove outdated todo in powernv IPMI driver
  ipmi: Clear smi_info->thread to prevent use-after-free during module unload
  ipmi: use correct string length
  ipmi_si: Fix error handling of platform device
  ipmi watchdog: fix typo in parameter description
  ipmi_si_platform: Fix typo in parameter description

Pull power supply and reset updates from Sebastian Reichel:

 - bq27xxx: add bq27521 support

 - drop unused imx-snvs-poweroff driver

 - improve axp288 driver

 - misc fixes

* tag 'for-v4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply: (32 commits)
  power: supply: max17042_battery: Always fall back to default platform-data
  power: supply: max17042_battery: Check battery current for status when supplied
  MAINTAINERS: Add AXP288 PMIC entry
  power: supply: axp288_fuel_gauge: Do not register our psy on (some) HDMI sticks
  power: supply: axp288_fuel_gauge: Optimize get_current()
  power: supply: axp288_fuel_gauge: Rework get_status()
  power: reset: account for const type of of_device_id.data
  power: supply: account for const type of of_device_id.data
  bq24190: Simplify code in property_is_writeable
  power: supply: axp288_fuel_gauge: Get iio-channels once during boot
  power: supply: axp288_charger: Properly stop work on probe-error / remove
  power: supply: axp288_charger: Simplify extcon cable handling
  power: supply: axp288_charger: Use the right property for the input current limit
  power: supply: axp288_charger: Pick lower input current limit not higher
  power: supply: axp288_charger: Do not cache input current limit value
  power: supply: axp288_charger: Remove no longer needed locking
  power: supply: axp288_charger: Use regmap_update_bits to set the input limits
  power: supply: axp288_charger: Cleanup some double empty lines
  power: supply: axp288_charger: Remove charger-enabled state tracking
  power: supply: axp288_charger: Add missing newlines to some messages
  ...

Pull HSI update from Sebastian Reichel:
 "Y2038 fix for cmt-speech"

* tag 'hsi-for-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-hsi:
  HSI: cmt_speech: use timespec64 instead of timespec

Pull GPIO updates from Linus Walleij:
 "The is the bulk of GPIO changes for the v4.16 kernel cycle. It is
  pretty calm this time around I think. I even got time to get to things
  like starting to clean up header includes.

  Core changes:

   - Disallow open drain and open source flags to be set simultaneously.
     This doesn't make electrical sense, and would the hardware actually
     respond to this setting, the result would be short circuit.

   - ACPI GPIO has a new core infrastructure for handling quirks. The
     quirks are there to deal with broken ACPI tables centrally instead
     of pushing the work to individual drivers. In the world of BIOS
     writers, the ACPI tables are perfect. Until they find a mistake in
     it. When such a mistake is found, we can patch it with a quirk. It
     should never happen, the problem is that it happens. So we
     accomodate for it.

   - Several documentation updates.

   - Revert the patch setting up initial direction state from reading
     the device. This was causing bad things for drivers that can't read
     status on all its pins. It is only affecting debugfs information
     quality.

   - Label descriptors with the device name if no explicit label is
     passed in.

   - Pave the ground for transitioning SPI and regulators to use GPIO
     descriptors by implementing some quirks in the device tree GPIO
     parsing code.

  New drivers:

   - New driver for the Access PCIe IDIO 24 family.

  Other:

   - Major refactorings and improvements to the GPIO mockup driver used
     for test and verification.

   - Moved the AXP209 driver over to pin control since it gained a pin
     control back-end. These patches will appear (with the same hashes)
     in the pin control pull request as well.

   - Convert the onewire GPIO driver w1-gpio to use descriptors. This is
     merged here since the W1 maintainers send very few pull requests
     and he ACKed it.

   - Start to clean up driver headers using <linux/gpio.h> to just use
     <linux/gpio/driver.h> as appropriate"

* tag 'gpio-v4.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (103 commits)
  gpio: Timestamp events in hardirq handler
  gpio: Fix kernel stack leak to userspace
  gpio: Fix a documentation spelling mistake
  gpio: Documentation update
  gpiolib: remove redundant initialization of pointer desc
  gpio: of: Fix NPE from OF flags
  gpio: stmpe: Delete an unnecessary variable initialisation in stmpe_gpio_probe()
  gpio: stmpe: Move an assignment in stmpe_gpio_probe()
  gpio: stmpe: Improve a size determination in stmpe_gpio_probe()
  gpio: stmpe: Use seq_putc() in stmpe_dbg_show()
  gpio: No NULL owner
  gpio: stmpe: i2c transfer are forbiden in atomic context
  gpio: davinci: Include proper header
  gpio: da905x: Include proper header
  gpio: cs5535: Include proper header
  gpio: crystalcove: Include proper header
  gpio: bt8xx: Include proper header
  gpio: bcm-kona: Include proper header
  gpio: arizona: Include proper header
  gpio: amd8111: Include proper header
  ...

Merge tag 'leds_for_4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds

Pull LED updates from Jacek Anaszewski:
 "New LED class driver:
   - introduce LM3692x dual string driver

  New LED trigger:
   - introduce a NETDEV trigger

  leds-lp8860:
   - various fixes to align with LED framework
   - add regulator enable during init
   - DT support related improvements

  Minor fixes and cleanups to the LED class drivers:
   - leds-pwm
   - ledtrig-activity
   - leds-blinkm
   - leds-as3645a
   - ledtrig-transient"

* tag 'leds_for_4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds:
  leds: ledtrig-transient: Add SPDX license identifiers
  leds: lp8860: Various fixes to align with LED framework
  leds: lp8860: Add DT parsing to retrieve the trigger node
  dt: bindings: lp8860: Add trigger binding to the lp8860
  leds: lp8860: Update the dt parsing for LED labeling
  dt: bindings: lp8860: Update DT label binding
  dt: bindings: lp8860: Update bindings for lp8860
  leds: as3645a: Fix line over 80 characters
  leds: as3645a: Fix quoted string split warning
  leds: lm3692x: Introduce LM3692x dual string driver
  dt: bindings: lm3692x: Add bindings for lm3692x LED driver
  leds: trigger: Introduce a NETDEV trigger
  leds: blinkm: avoid uninitialized data use
  ledtrig-activity: Grammar s/a immediate/an immediate/
  leds: pwm: Remove unneeded header file
  leds: lp8860: Add regulator enable during init
  leds: lp8860: Fix linuxdoc format for structure

Pull RDMA subsystem updates from Jason Gunthorpe:
 "Overall this cycle did not have any major excitement, and did not
  require any shared branch with netdev.

  Lots of driver updates, particularly of the scale-up and performance
  variety. The largest body of core work was Parav's patches fixing and
  restructing some of the core code to make way for future RDMA
  containerization.

  Summary:

   - misc small driver fixups to
     bnxt_re/hfi1/qib/hns/ocrdma/rdmavt/vmw_pvrdma/nes

   - several major feature adds to bnxt_re driver: SRIOV VF RoCE
     support, HugePages support, extended hardware stats support, and
     SRQ support

   - a notable number of fixes to the i40iw driver from debugging scale
     up testing

   - more work to enable the new hip08 chip in the hns driver

   - misc small ULP fixups to srp/srpt//ipoib

   - preparation for srp initiator and target to support the RDMA-CM
     protocol for connections

   - add RDMA-CM support to srp initiator, srp target is still a WIP

   - fixes for a couple of places where ipoib could spam the dmesg log

   - fix encode/decode of FDR/EDR data rates in the core

   - many patches from Parav with ongoing work to clean up
     inconsistencies and bugs in RoCE support around the rdma_cm

   - mlx5 driver support for the userspace features 'thread domain',
     'wallclock timestamps' and 'DV Direct Connected transport'. Support
     for the firmware dual port rocee capability

   - core support for more than 32 rdma devices in the char dev
     allocation

   - kernel doc updates from Randy Dunlap

   - new netlink uAPI for inspecting RDMA objects similar in spirit to 'ss'

   - one minor change to the kobject code acked by Greg KH"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (259 commits)
  RDMA/nldev: Provide detailed QP information
  RDMA/nldev: Provide global resource utilization
  RDMA/core: Add resource tracking for create and destroy PDs
  RDMA/core: Add resource tracking for create and destroy CQs
  RDMA/core: Add resource tracking for create and destroy QPs
  RDMA/restrack: Add general infrastructure to track RDMA resources
  RDMA/core: Save kernel caller name when creating PD and CQ objects
  RDMA/core: Use the MODNAME instead of the function name for pd callers
  RDMA: Move enum ib_cq_creation_flags to uapi headers
  IB/rxe: Change RDMA_RXE kconfig to use select
  IB/qib: remove qib_keys.c
  IB/mthca: remove mthca_user.h
  RDMA/cm: Fix access to uninitialized variable
  RDMA/cma: Use existing netif_is_bond_master function
  IB/core: Avoid SGID attributes query while converting GID from OPA to IB
  RDMA/mlx5: Avoid memory leak in case of XRCD dealloc failure
  IB/umad: Fix use of unprotected device pointer
  IB/iser: Combine substrings for three messages
  IB/iser: Delete an unnecessary variable initialisation in iser_send_data_out()
  IB/iser: Delete an error message for a failed memory allocation in iser_send_data_out()
  ...

Pull dmaengine updates from Vinod Koul:
 "This time is smallish update with updates mainly to drivers:

   - updates to xilinx and zynqmp dma controllers

   - update reside calculation for rcar controller

   - more RSTify fixes for documentation

   - add support for race free transfer termination and updating for
     users for that

   - support for new rev of hidma with addition new APIs to get device
     match data in ACPI/OF

   - random updates to bunch of other drivers"

* tag 'dmaengine-4.16-rc1' of git://git.infradead.org/users/vkoul/slave-dma: (47 commits)
  dmaengine: dmatest: fix container_of member in dmatest_callback
  dmaengine: stm32-dmamux: Remove unnecessary platform_get_resource() error check
  dmaengine: sprd: statify 'sprd_dma_prep_dma_memcpy'
  dmaengine: qcom_hidma: simplify DT resource parsing
  dmaengine: xilinx_dma: Free BD consistent memory
  dmaengine: xilinx_dma: Fix warning variable prev set but not used
  dmaengine: xilinx_dma: properly configure the SG mode bit in the driver for cdma
  dmaengine: doc: format struct fields using monospace
  dmaengine: doc: fix bullet list formatting
  dmaengine: ti-dma-crossbar: Fix event mapping for TPCC_EVT_MUX_60_63
  dmaengine: cppi41: Fix channel queues array size check
  dmaengine: imx-sdma: Add MODULE_FIRMWARE
  dmaengine: xilinx_dma: Fix typos
  dmaengine: xilinx_dma: Differentiate probe based on the ip type
  dmaengine: xilinx_dma: fix style issues from checkpatch
  dmaengine: xilinx_dma: Fix kernel doc warnings
  dmaengine: xilinx_dma: Fix race condition in the driver for multiple descriptor scenario
  dmaeninge: xilinx_dma: Fix bug in multiple frame stores scenario in vdma
  dmaengine: xilinx_dma: Check for channel idle state before submitting dma descriptor
  dmaengine: zynqmp_dma: Fix race condition in the probe
  ...

Pull dma mapping updates from Christoph Hellwig:
 "Except for a runtime warning fix from Christian this is all about
  consolidation of the generic no-IOMMU code, a well as the glue code
  for swiotlb.

  All the code is based on the x86 implementation with hooks to allow
  all architectures that aren't cache coherent to use it.

  The x86 conversion itself has been deferred because the x86
  maintainers were a little busy in the last months"

* tag 'dma-mapping-4.16' of git://git.infradead.org/users/hch/dma-mapping: (57 commits)
  MAINTAINERS: add the iommu list for swiotlb and xen-swiotlb
  arm64: use swiotlb_alloc and swiotlb_free
  arm64: replace ZONE_DMA with ZONE_DMA32
  mips: use swiotlb_{alloc,free}
  mips/netlogic: remove swiotlb support
  tile: use generic swiotlb_ops
  tile: replace ZONE_DMA with ZONE_DMA32
  unicore32: use generic swiotlb_ops
  ia64: remove an ifdef around the content of pci-dma.c
  ia64: clean up swiotlb support
  ia64: use generic swiotlb_ops
  ia64: replace ZONE_DMA with ZONE_DMA32
  swiotlb: remove various exports
  swiotlb: refactor coherent buffer allocation
  swiotlb: refactor coherent buffer freeing
  swiotlb: wire up ->dma_supported in swiotlb_dma_ops
  swiotlb: add common swiotlb_map_ops
  swiotlb: rename swiotlb_free to swiotlb_exit
  x86: rename swiotlb_dma_ops
  powerpc: rename swiotlb_dma_ops
  ...

Pull SCSI updates from James Bottomley:
 "This is mostly updates of the usual driver suspects: arcmsr,
  scsi_debug, mpt3sas, lpfc, cxlflash, qla2xxx, aacraid, megaraid_sas,
  hisi_sas.

  We also have a rework of the libsas hotplug handling to make it more
  robust, a slew of 32 bit time conversions and fixes, and a host of the
  usual minor updates and style changes. The biggest potential for
  regressions is the libsas hotplug changes, but so far they seem stable
  under testing"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (313 commits)
  scsi: qla2xxx: Fix logo flag for qlt_free_session_done()
  scsi: arcmsr: avoid do_gettimeofday
  scsi: core: Add VENDOR_SPECIFIC sense code definitions
  scsi: qedi: Drop cqe response during connection recovery
  scsi: fas216: fix sense buffer initialization
  scsi: ibmvfc: Remove unneeded semicolons
  scsi: hisi_sas: fix a bug in hisi_sas_dev_gone()
  scsi: hisi_sas: directly attached disk LED feature for v2 hw
  scsi: hisi_sas: devicetree: bindings: add LED feature for v2 hw
  scsi: megaraid_sas: NVMe passthrough command support
  scsi: megaraid: use ktime_get_real for firmware time
  scsi: fnic: use 64-bit timestamps
  scsi: qedf: Fix error return code in __qedf_probe()
  scsi: devinfo: fix format of the device list
  scsi: qla2xxx: Update driver version to 10.00.00.05-k
  scsi: qla2xxx: Add XCB counters to debugfs
  scsi: qla2xxx: Fix queue ID for async abort with Multiqueue
  scsi: qla2xxx: Fix warning for code intentation in __qla24xx_handle_gpdb_event()
  scsi: qla2xxx: Fix warning during port_name debug print
  scsi: qla2xxx: Fix warning in qla2x00_async_iocb_timeout()
  ...

Merge tag 'for-4.16/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - DM core fixes to ensure that bio submission follows a depth-first
   tree walk; this is critical to allow forward progress without the
   need to use the bioset's BIOSET_NEED_RESCUER.

 - Remove DM core's BIOSET_NEED_RESCUER based dm_offload infrastructure.

 - DM core cleanups and improvements to make bio-based DM more efficient
   (e.g. reduced memory footprint as well leveraging per-bio-data more).

 - Introduce new bio-based mode (DM_TYPE_NVME_BIO_BASED) that leverages
   the more direct IO submission path in the block layer; this mode is
   used by DM multipath and also optimizes targets like DM thin-pool
   that stack directly on NVMe data device.

 - DM multipath improvements to factor out legacy SCSI-only (e.g.
   scsi_dh) code paths to allow for more optimized support for NVMe
   multipath.

 - A fix for DM multipath path selectors (service-time and queue-length)
   to select paths in a more balanced way; largely academic but doesn't
   hurt.

 - Numerous DM raid target fixes and improvements.

 - Add a new DM "unstriped" target that enables Intel to workaround
   firmware limitations in some NVMe drives that are striped internally
   (this target also works when stacked above the DM "striped" target).

 - Various Documentation fixes and improvements.

 - Misc cleanups and fixes across various DM infrastructure and targets
   (e.g. bufio, flakey, log-writes, snapshot).

* tag 'for-4.16/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (69 commits)
  dm cache: Documentation: update default migration_throttling value
  dm mpath selector: more evenly distribute ties
  dm unstripe: fix target length versus number of stripes size check
  dm thin: fix trailing semicolon in __remap_and_issue_shared_cell
  dm table: fix NVMe bio-based dm_table_determine_type() validation
  dm: various cleanups to md->queue initialization code
  dm mpath: delay the retry of a request if the target responded as busy
  dm mpath: return DM_MAPIO_DELAY_REQUEUE if QUEUE_IO or PG_INIT_REQUIRED
  dm mpath: return DM_MAPIO_REQUEUE on blk-mq rq allocation failure
  dm log writes: fix max length used for kstrndup
  dm: backfill missing calls to mutex_destroy()
  dm snapshot: use mutex instead of rw_semaphore
  dm flakey: check for null arg_name in parse_features()
  dm thin: extend thinpool status format string with omitted fields
  dm thin: fixes in thin-provisioning.txt
  dm thin: document representation of <highest mapped sector> when there is none
  dm thin: fix documentation relative to low water mark threshold
  dm cache: be consistent in specifying sectors and SI units in cache.txt
  dm cache: delete obsoleted paragraph in cache.txt
  dm cache: fix grammar in cache-policies.txt
  ...

Pull MD updates from Shaohua Li:
 "Some small fixes for MD:

   - fix raid5-cache potential problems if raid5 cache isn't fully
     recovered

   - fix a wait-within-wait warning in raid1/10

   - make raid5-PPL support disks with writeback cache enabled"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md:
  raid5-ppl: PPL support for disks with write-back cache enabled
  md/r5cache: print more info of log recovery
  md/raid1,raid10: silence warning about wait-within-wait
  md: introduce new personality funciton start()

Pull xfs updates from Darrick Wong:
 "This merge cycle, we're again some substantive changes to XFS.

  Metadata verifiers have been restructured to provide more detail about
  which part of a metadata structure failed checks, and we've enhanced
  the new online fsck feature to cross-reference extent allocation
  information with the other metadata structures. With this pull, the
  metadata verification part of online fsck is more or less finished,
  though the feature is still experimental and still disabled by
  default.

  We're also preparing to remove the EXPERIMENTAL tag from a couple of
  features this cycle. This week we're committing a bunch of space
  accounting fixes for reflink and removing the EXPERIMENTAL tag from
  reflink; I anticipate that we'll be ready to do the same for the
  reverse mapping feature next week. (I don't have any pending fixes for
  rmap; however I wish to remove the tags one at a time.)

  This giant pile of patches has been run through a full xfstests run
  over the weekend and through a quick xfstests run against this
  morning's master, with no major failures reported. Let me know if
  there's any merge problems -- git merge reported that one of our
  patches touched the same function as the i_version series, but it
  resolved things cleanly.

  Summary:

   - Log faulting code locations when verifiers fail, for improved
     diagnosis of corrupt filesystems.

   - Implement metadata verifiers for local format inode fork data.

   - Online scrub now cross-references metadata records with other
     metadata.

   - Refactor the fs geometry ioctl generation functions.

   - Harden various metadata verifiers.

   - Fix various accounting problems.

   - Fix uncancelled transactions leaking when xattr functions fail.

   - Prevent the copy-on-write speculative preallocation garbage
     collector from racing with writeback.

   - Emit log reservation type information as trace data so that we can
     compare against xfsprogs.

   - Fix some erroneous asserts in the online scrub code.

   - Clean up the transaction reservation calculations.

   - Fix various minor bugs in online scrub.

   - Log complaints about mixed dio/buffered writes once per day and
     less noisily than before.

   - Refactor buffer log item lists to use list_head.

   - Break PNFS leases before reflinking blocks.

   - Reduce lock contention on reflink source files.

   - Fix some quota accounting problems with reflink.

   - Fix a serious corruption problem in the direct cow write code where
     we fed bad iomaps to the vfs iomap consumers.

   - Various other refactorings.

   - Remove EXPERIMENTAL tag from reflink!"

* tag 'xfs-4.16-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (94 commits)
  xfs: remove experimental tag for reflinks
  xfs: don't screw up direct writes when freesp is fragmented
  xfs: check reflink allocation mappings
  iomap: warn on zero-length mappings
  xfs: treat CoW fork operations as delalloc for quota accounting
  xfs: only grab shared inode locks for source file during reflink
  xfs: allow xfs_lock_two_inodes to take different EXCL/SHARED modes
  xfs: reflink should break pnfs leases before sharing blocks
  xfs: don't clobber inobt/finobt cursors when xref with rmap
  xfs: skip CoW writes past EOF when writeback races with truncate
  xfs: preserve i_rdev when recycling a reclaimable inode
  xfs: refactor accounting updates out of xfs_bmap_btalloc
  xfs: refactor inode verifier corruption error printing
  xfs: make tracepoint inode number format consistent
  xfs: always zero di_flags2 when we free the inode
  xfs: call xfs_qm_dqattach before performing reflink operations
  xfs: bmap code cleanup
  Use list_head infra-structure for buffer's log items list
  Split buffer's b_fspriv field
  Get rid of xfs_buf_log_item_t typedef
  ...

Pull get_user_pages_fast updates from Al Viro:
 "A bit more get_user_pages work"

* 'work.get_user_pages_fast' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  kvm: switch get_user_page_nowait() to get_user_pages_unlocked()
  __get_user_pages_locked(): get rid of notify_drop argument
  get_user_pages_unlocked(): pass true to __get_user_pages_locked() notify_drop
  cris: switch to get_user_pages_fast()
  fold __get_user_pages_unlocked() into its sole remaining caller

Pull misc vfs updates from Al Viro:
 "All kinds of misc stuff, without any unifying topic, from various
  people.

  Neil's d_anon patch, several bugfixes, introduction of kvmalloc
  analogue of kmemdup_user(), extending bitfield.h to deal with
  fixed-endians, assorted cleanups all over the place..."

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits)
  alpha: osf_sys.c: use timespec64 where appropriate
  alpha: osf_sys.c: fix put_tv32 regression
  jffs2: Fix use-after-free bug in jffs2_iget()'s error handling path
  dcache: delete unused d_hash_mask
  dcache: subtract d_hash_shift from 32 in advance
  fs/buffer.c: fold init_buffer() into init_page_buffers()
  fs: fold __inode_permission() into inode_permission()
  fs: add RWF_APPEND
  sctp: use vmemdup_user() rather than badly open-coding memdup_user()
  snd_ctl_elem_init_enum_names(): switch to vmemdup_user()
  replace_user_tlv(): switch to vmemdup_user()
  new primitive: vmemdup_user()
  memdup_user(): switch to GFP_USER
  eventfd: fold eventfd_ctx_get() into eventfd_ctx_fileget()
  eventfd: fold eventfd_ctx_read() into eventfd_read()
  eventfd: convert to use anon_inode_getfd()
  nfs4file: get rid of pointless include of btrfs.h
  uvc_v4l2: clean copyin/copyout up
  vme_user: don't use __copy_..._user()
  usx2y: don't bother with memdup_user() for 16-byte structure
  ...

Pull GFS2 updates from Bob Peterson:
 "We've got 30 patches for this merge window. These generally fall into
  five categories:

   - code cleanups

   - patches related to adding PUNCH_HOLE support to GFS2

   - support for new fields in resource group headers

   - a few bug fixes

   - support for new fields in journal log headers. These new fields,
     which were previously unused, are designed to make it easier to
     track down file system corruption, and allow fsck.gfs2 to make more
     intelligent decisions when finding and fixing file system
     corruption.

  Details:

   - Two patches from Abhi Das, to trim the ordered writes list, which
     used to grow uncontrollably until unmount.

   - Several patches from Andreas Gruenbacher: remove an unused
     parameter from function gfs2_write_jdata_pagevec, remove a
     pointless BUG_ON, clean up an error patch in trunc_start, remove
     some unused parameters from truncate, make gfs2_journaled_truncate
     more efficient, clean up the support functions for truncate, fix
     metadata read-ahead for truncate to make it faster, fix up the
     non-recursive truncate code, rework and rename
     gfs2_block_truncate_page, generalize the non-recursive truncate
     code so it can take a range of values for punch_hole support,
     introduce new PUNCH_HOLE support that take advantage of the
     previous patches, add fallocate support with PUNCH_HOLE, fix some
     typos in the comments, add the function gfs2_max_stuffed_size to
     replace a piece of code that was needlessly repeated throughout
     GFS2, a minor cleanup to function gfs2_page_add_databufs, get rid
     of function gfs2_log_header_in in preparation for the new log
     header fields, and also fix up some missing newlines in kernel
     messages.

   - Andy Price added a new field to resource groups to indicate where
     the next one should be, to allow fsck.gfs2 to make better repairs.
     He also added new rindex fields for consistency checking, and added
     a crc field to resource group headers for consistency checking.

   - I reduced redundancy in functions common to freeing dinodes, and
     when writing log headers between the journalling code and journal
     recovery code. Also added new fields to journal log headers based
     on a prototype from Steve Whitehouse, and log the source of journal
     log headers so we can better track down journal corruption. Minor
     comment typo fix and a fix for a BUG in an unlink error path.

   - Steve Whitehouse contributed a patch to fix an incorrect use of the
     gfs2_blk2rgrpd function.

   - Tetsuo Handa contributed a patch that fixes incorrect error
     handling in function init_gfs2_fs"

* tag 'gfs2-4.16.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2: (30 commits)
  gfs2: Add a few missing newlines in messages
  gfs2: Remove inode from ordered write list in gfs2_write_inode()
  GFS2: Don't try to end a non-existent transaction in unlink
  GFS2: Fix minor comment typo
  GFS2: Log the reason for log flushes in every log header
  GFS2: Introduce new gfs2_log_header_v2
  gfs2: Get rid of gfs2_log_header_in
  gfs2: Minor gfs2_page_add_databufs cleanup
  gfs2: Add gfs2_max_stuffed_size
  gfs2: Typo fixes
  gfs2: Implement fallocate(FALLOC_FL_PUNCH_HOLE)
  gfs2: Turn trunc_dealloc into punch_hole
  gfs2: Generalize truncate code
  Turn gfs2_block_truncate_page into gfs2_block_zero_range
  gfs2: Improve non-recursive delete algorithm
  gfs2: Fix metadata read-ahead during truncate
  gfs2: Clean up {lookup,fillup}_metapath
  gfs2: Remove minor gfs2_journaled_truncate inefficiencies
  gfs2: truncate: Remove unnecessary oldsize parameters
  gfs2: Clean up trunc_start error path
  ...

If devpts_ptmx_path() returns an error code, then devpts_mntget()
dereferences an ERR_PTR():

    BUG: unable to handle kernel paging request at fffffffffffffff5
    IP: devpts_mntget+0x13f/0x280 fs/devpts/inode.c:173

Fix it by returning early in the error paths.

Reproducer:

    #define _GNU_SOURCE
    #include <fcntl.h>
    #include <sched.h>
    #include <sys/ioctl.h>
    #define TIOCGPTPEER _IO('T', 0x41)

    int main()
    {
        for (;;) {
            int fd = open("/dev/ptmx", 0);
            unshare(CLONE_NEWNS);
            ioctl(fd, TIOCGPTPEER, 0);
        }
    }

Fixes: 311fc65c ("pty: Repair TIOCGPTPEER")
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: <stable@vger.kernel.org> # v4.13+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

As Linus points out:

    The inode_cmp_iversion{+raw}() functions are pure and utter crap.

    Why?

    You say that they return 0/negative/positive, but they do so in a
    completely broken manner. They return that ternary value as the
    sequence number difference in a 's64', which means that if you
    actually care about that ternary value, and do the *sane* thing that
    the kernel-doc of the function implies is the right thing, you would
    do

        int cmp = inode_cmp_iversion(inode, old);
        if (cmp < 0 ...

    and as a result you get code that looks sane, but that doesn't
    actually *WORK* right.

Since none of the callers actually care about the ternary value here,
convert the inode_cmp_iversion{+raw} functions to just return a boolean
value (false for matching, true for non-matching).

This matches the existing use of these functions just fine, and makes it
simple to convert them to return a ternary value in the future if we
grow callers that need it.

With this change we can also reimplement inode_cmp_iversion in a simpler
way using inode_peek_iversion.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull 'immediate' feature removal from Miroslav Benes.

Pull assorted small fixes queued for merge window.

Pull Wacom device driver updates. These don't have to go on top of the
hid_have_special_driver[] revamp, as the whole group is assumed to
have a special driver based on VID.

Pull hid-elo device detection fix

Merge branches 'for-4.16/hid-quirks-cleanup/asus', 'for-4.16/hid-quirks-cleanup/elecom', 'for-4.16/hid-quirks-cleanup/ish', 'for-4.16/hid-quirks-cleanup/multitouch', 'for-4.16/hid-quirks-cleanup/pixart', 'for-4.16/hid-quirks-cleanup/rmi', 'for-4.16/hid-quirks-cleanup/sony' and 'for-4.16/hid-quirks-cleanup/toshiba' into for-linus

Pull assorted device driver fixes (ASUS, Elecom, Intel-ISH, Multitouch, PixArt, RMI,
Sony and Toshiba) based on top the hid-quirks revamp.

This series from Benjamin Tissoires finally removes one of the big PITAs
in the hid-core, which is the absolute need of having added all the new
device IDs into the horrid hid_have_special_driver[]