The tiadc_irq_h(int irq, void *private) function is handling FIFO
overruns by clearing flags, disabling and enabling the ADC to
recover.

If the ADC is running in continuous mode a FIFO overrun happens
regularly. If the disabling of the ADC happens concurrently with
a new conversion. It might happen that the enabling of the ADC
is ignored by the hardware. This stops the ADC permanently. No
more interrupts are triggered.

According to the AM335x Reference Manual (SPRUH73H October 2011 -
Revised April 2013 - Chapter 12.4 and 12.5) it is necessary to
check the ADC FSM bits in REG_ADCFSM before enabling the ADC
again. Because the disabling of the ADC is done right after the
current conversion has been finished.

To trigger this bug it is necessary to run the ADC in continuous
mode. The ADC values of all channels need to be read in an endless
loop. The bug appears within the first 6 hours (~5.4 million
handled FIFO overruns). The user space application will hang on
reading new values from the character device.

Fixes: ca9a5638 ("iio: ti_am335x_adc: Add continuous sampling
support")
Signed-off-by: Michael Engl <michael.engl@wjw-solutions.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Use the IS_ENABLED() helper macro to ensure that the configfs group is
initialized either when configfs is built-in or when configfs is built as a
module. Otherwise software device creation will result in undefined
behaviour when configfs is built as a module since the configfs group for
the device not properly initialized.

Similar to commit b2f0c096 ("iio: sw-trigger: Fix config group
initialization").

Fixes: 0f3a8c3f ("iio: Add support for creating IIO devices via configfs")
Reported-by: Miguel Robles <miguel.robles@farole.net>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Daniel Baluta <daniel.baluta@gmail.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Even if bus is not hot-pluggable, devices can be unbound from the
driver via sysfs, so we should not be using __exit annotations on
remove() methods. The only exception is drivers registered with
platform_driver_probe() which specifically disables sysfs bind/unbind
attributes.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: hid-sensor-trigger: Change get poll value function order to avoid sensor properties losing after resume from S3

In function _hid_sensor_power_state(), when hid_sensor_read_poll_value()
is called, sensor's all properties will be updated by the value from
sensor hardware/firmware.
In some implementation, sensor hardware/firmware will do a power cycle
during S3. In this case, after resume, once hid_sensor_read_poll_value()
is called, sensor's all properties which are kept by driver during S3
will be changed to default value.
But instead, if a set feature function is called first, sensor
hardware/firmware will be recovered to the last status. So change the
sensor_hub_set_feature() calling order to behind of set feature function
to avoid sensor properties lose.
Signed-off-by: Song Hongyan <hongyan.song@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Pull more KVM updates from Radim Krčmář:
 "Second batch of KVM changes for the 4.11 merge window:

  PPC:
   - correct assumption about ASDR on POWER9
   - fix MMIO emulation on POWER9

  x86:
   - add a simple test for ioperm
   - cleanup TSS (going through KVM tree as the whole undertaking was
     caused by VMX's use of TSS)
   - fix nVMX interrupt delivery
   - fix some performance counters in the guest

  ... and two cleanup patches"

* tag 'kvm-4.11-2' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: nVMX: Fix pending events injection
  x86/kvm/vmx: remove unused variable in segment_base()
  selftests/x86: Add a basic selftest for ioperm
  x86/asm: Tidy up TSS limit code
  kvm: convert kvm.users_count from atomic_t to refcount_t
  KVM: x86: never specify a sample period for virtualized in_tx_cp counters
  KVM: PPC: Book3S HV: Don't use ASDR for real-mode HPT faults on POWER9
  KVM: PPC: Book3S HV: Fix software walk of guest process page tables

Pull documentation fixes from Jonathan Corbet:
 "A few fixes for the docs tree, including one for a 4.11 build
  regression"

* tag 'docs-4.11-fixes' of git://git.lwn.net/linux:
  Documentation/sphinx: fix primary_domain configuration
  docs: Fix htmldocs build failure
  doc/ko_KR/memory-barriers: Update control-dependencies section
  pcieaer doc: update the link
  Documentation: Update path to sysrq.txt

Pull staging/IIO driver fixes from Greg KH:
 "Here are a few small staging and IIO driver fixes for issues that
  showed up after the big set if changes you merged last week.

  Nothing major, just small bugs resolved in some IIO drivers, a lustre
  allocation fix, and some RaspberryPi driver fixes for reported
  problems, as well as a MAINTAINERS entry update.

  All of these have been in linux-next for a week with no reported
  issues"

* tag 'staging-4.11-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: fsl-mc: fix warning in DT ranges parser
  MAINTAINERS: Remove Noralf Trønnes as fbtft maintainer
  staging: vchiq_2835_arm: Make cache-line-size a required DT property
  staging: bcm2835/mmal-vchiq: unlock on error in buffer_from_host()
  staging/lustre/lnet: Fix allocation size for sv_cpt_data
  iio: adc: xilinx: Fix error handling
  iio: 104-quad-8: Fix off-by-one error when addressing flag register
  iio: adc: handle unknow of_device_id data

Pull crypto fixes from Herbert Xu:

 - vmalloc stack regression in CCM

 - Build problem in CRC32 on ARM

 - Memory leak in cavium

 - Missing Kconfig dependencies in atmel and mediatek

 - XTS Regression on some platforms (s390 and ppc)

 - Memory overrun in CCM test vector

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: vmx - Use skcipher for xts fallback
  crypto: vmx - Use skcipher for cbc fallback
  crypto: testmgr - Pad aes_ccm_enc_tv_template vector
  crypto: arm/crc32 - add build time test for CRC instruction support
  crypto: arm/crc32 - fix build error with outdated binutils
  crypto: ccm - move cbcmac input off the stack
  crypto: xts - Propagate NEED_FALLBACK bit
  crypto: api - Add crypto_requires_off helper
  crypto: atmel - CRYPTO_DEV_MEDIATEK should depend on HAS_DMA
  crypto: atmel - CRYPTO_DEV_ATMEL_TDES and CRYPTO_DEV_ATMEL_SHA should depend on HAS_DMA
  crypto: cavium - fix leak on curr if curr->head fails to be allocated
  crypto: cavium - Fix couple of static checker errors

Pull misc final vfs updates from Al Viro:
 "A few unrelated patches that got beating in -next.

  Everything else will have to go into the next window ;-/"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  hfs: fix hfs_readdir()
  selftest for default_file_splice_read() infoleak
  9p: constify ->d_name handling

Pull more SCSI updates from James Bottomley:
 "This is the set of stuff that didn't quite make the initial pull and a
  set of fixes for stuff which did.

  The new stuff is basically lpfc (nvme), qedi and aacraid. The fixes
  cover a lot of previously submitted stuff, the most important of which
  probably covers some of the failing irq vectors allocation and other
  fallout from having the SCSI command allocated as part of the block
  allocation functions"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (59 commits)
  scsi: qedi: Fix memory leak in tmf response processing.
  scsi: aacraid: remove redundant zero check on ret
  scsi: lpfc: use proper format string for dma_addr_t
  scsi: lpfc: use div_u64 for 64-bit division
  scsi: mac_scsi: Fix MAC_SCSI=m option when SCSI=m
  scsi: cciss: correct check map error.
  scsi: qla2xxx: fix spelling mistake: "seperator" -> "separator"
  scsi: aacraid: Fixed expander hotplug for SMART family
  scsi: mpt3sas: switch to pci_alloc_irq_vectors
  scsi: qedf: fixup compilation warning about atomic_t usage
  scsi: remove scsi_execute_req_flags
  scsi: merge __scsi_execute into scsi_execute
  scsi: simplify scsi_execute_req_flags
  scsi: make the sense header argument to scsi_test_unit_ready mandatory
  scsi: sd: improve TUR handling in sd_check_events
  scsi: always zero sshdr in scsi_normalize_sense
  scsi: scsi_dh_emc: return success in clariion_std_inquiry()
  scsi: fix memory leak of sdpk on when gd fails to allocate
  scsi: sd: make sd_devt_release() static
  scsi: qedf: Add QLogic FastLinQ offload FCoE driver framework.
  ...

Pull libnvdimm fixes from Dan Williams:
 "A fix and regression test case for nvdimm namespace label
  compatibility.

  Details:

   - An "nvdimm namespace label" is metadata on an nvdimm that
     provisions dimm capacity into a "namespace" that can host a block
     device / dax-filesytem, or a device-dax character device.

     A namespace is an object that other operating environment and
     platform firmware needs to comprehend for capabilities like booting
     from an nvdimm.

     The label metadata contains a checksum that Linux was not
     calculating correctly leading to other environments rejecting the
     Linux label.

   These have received a build success notification from the kbuild
   robot, and a positive test result from Nick who reported the problem"

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  nfit, libnvdimm: fix interleave set cookie calculation
  tools/testing/nvdimm: make iset cookie predictable

Pull PCI fixes from Bjorn Helgaas:

 - fix NULL pointer dereferences in many DesignWare-based drivers due to
   refactoring error

 - fix Altera config write breakage due to my refactoring error

* tag 'pci-v4.11-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: altera: Fix TLP_CFG_DW0 for TLP write
  PCI: dwc: Fix crashes seen due to missing assignments

Pull parisc fixes and cleanups from Helge Deller:
 "Nothing really important in this patchset: fix resource leaks in error
  paths, coding style cleanups and code removal"

* 'parisc-4.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Remove flush_user_dcache_range and flush_user_icache_range
  parisc: fix a printk
  parisc: ccio-dma: Handle return NULL error from ioremap_nocache
  parisc: Define access_ok() as macro
  parisc: eisa: Fix resource leaks in error paths
  parisc: eisa: Remove coding style errors

Pull Xtensa updates from Max Filippov:

 - clean up bootable image build targets: provide separate 'Image',
   'zImage' and 'uImage' make targets that only build corresponding
   image type. Make 'all' build all images appropriate for a platform

 - allow merging vectors code into .text section as a preparation step
   for XIP support

 - fix handling external FDT when the kernel is built without
   BLK_DEV_INITRD support

* tag 'xtensa-20170303' of git://github.com/jcmvbkbc/linux-xtensa:
  xtensa: allow merging vectors into .text section
  xtensa: clean up bootable image build targets
  xtensa: move parse_tag_fdt out of #ifdef CONFIG_BLK_DEV_INITRD

Pull ARM SoC late DT updates from Arnd Bergmann:
 "These updates have been kept in a separate branch mostly because they
  rely on updates to the respective clk drivers to keep the shared
  header files in sync.

  This includes two branches for arm64 dt updates, both following up on
  earlier changes for the same platforms that are already merged:

  Samsung:
   - add USB3 support in Exynos7
   - minor PM related updates

  Amlogic:
   - new machines: WeTek Set-top-boxes
   - various devices added to DT

  There are also a couple of bugfixes that trickled in since the start
  of the merge window:

   - The moxart_defconfig was not building the intended platform
   - CPU-hotplug was broken on ux500
   - Coresight was broken on Juno (never worked)"

* tag 'armsoc-late' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (26 commits)
  ARM: deconfig: fix the moxart defconfig
  ARM: ux500: resume the second core properly
  arm64: dts: juno: update definition for programmable replicator
  arm64: dts: exynos: Add regulators for Vbus and Vbus-Boost
  arm64: dts: exynos: Add USB 3.0 controller node for Exynos7
  arm64: dts: exynos: Use macros for pinctrl configuration on Exynos7
  pinctrl: dt-bindings: samsung: Add Exynos7 specific pinctrl macro definitions
  arm64: dts: exynos: Add initial configuration for DISP clocks for TM2/TM2e
  ARM64: dts: meson-gxbb-p200: add ADC laddered keys
  ARM64: dts: meson: meson-gx: add the SAR ADC
  ARM64: dts: meson-gxl: add the pwm_ao_b pin
  ARM64: dts: meson-gx: add the missing pwm_AO_ab node
  clk: gxbb: fix CLKID_ETH defined twice
  ARM64: dts: meson-gxl: rename Nexbox A95x for consistency
  clk: gxbb: add the SAR ADC clocks and expose them
  dt-bindings: amlogic: Add WeTek boards
  ARM64: dts: meson-gxbb: Add support for WeTek Hub and Play
  dt-bindings: vendor-prefix: Add wetek vendor prefix
  ARM64: dts: meson-gxm: Rename q200 and q201 DT files for consistency
  ARM64: dts: meson-gx: Add HDMI HPD/DDC pinctrl nodes
  ...

Pull SMB3 fixes from Steve French:
 "Some small bug fixes as well as SMB2.1/SMB3 enablement for DFS (global
  namespace) which previously was only enabled for CIFS"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  smb2: Enforce sec= mount option
  CIFS: Fix sparse warnings
  CIFS: implement get_dfs_refer for SMB2+
  CIFS: use DFS pathnames in SMB2+ Create requests
  CIFS: set signing flag in SMB2+ TreeConnect if needed
  CIFS: let ses->ipc_tid hold smb2 TreeIds
  CIFS: add use_ipc flag to SMB2_ioctl()
  CIFS: add build_path_from_dentry_optional_prefix()
  CIFS: move DFS response parsing out of SMB1 code
  CIFS: Fix possible use after free in demultiplex thread

With Sphinx 1.5.3 I get the warning:

	WARNING: primary_domain 'C' not found, ignored.

It seems that domain names in Sphinx are case-sensitive and for the C
domain the name must be lower case.
Signed-off-by: John Keeping <john@metanate.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Build of HTML docs failing due to conversion of deviceiobook.tmpl in
8a8a602f and regulator.tmpl in 028f2533 to RST without removing from
DOCBOOKS in Makefile, resulting (in the case of deviceiobook) the
following error:

make[1]: *** No rule to make target 'Documentation/DocBook/deviceiobook.xml', needed by 'Documentation/DocBook/deviceiobook.aux.xml'.  Stop.
Makefile:1452: recipe for target 'htmldocs' failed
make: *** [htmldocs] Error 2

Update DOCBOOKS to reflect available books.
Signed-off-by: Martyn Welch <martyn.welch@collabora.co.uk>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

This commit applies upstream change, commit c8241f85 ("doc: Update
control-dependencies section of memory-barriers.txt"), to Korean
translation.
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

The original link is empty, replace it.
Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Commit 9d85025b ("docs-rst: create an user's manual book") moved the
sysrq.txt leaving old paths in the kernel docs.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Pull fuse update from Miklos Szeredi:
 "A bugfix and cleanups"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: release: private_data cannot be NULL
  fuse: cleanup fuse_file refcounting
  fuse: add missing FR_FORCE

Pull overlayfs updates from Miklos Szeredi:
 "Because copy up can take a long time, serialized copy ups could be a
  big performance bottleneck. This update allows concurrent copy up of
  regular files eliminating this potential problem.

  There are also minor fixes"

* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: drop CAP_SYS_RESOURCE from saved mounter's credentials
  ovl: properly implement sync_filesystem()
  ovl: concurrent copy up of regular files
  ovl: introduce copy up waitqueue
  ovl: copy up regular file using O_TMPFILE
  ovl: rearrange code in ovl_copy_up_locked()
  ovl: check if upperdir fs supports O_TMPFILE

Pull vfs 'statx()' update from Al Viro.

This adds the new extended stat() interface that internally subsumes our
previous stat interfaces, and allows user mode to specify in more detail
what kind of information it wants.

It also allows for some explicit synchronization information to be
passed to the filesystem, which can be relevant for network filesystems:
is the cached value ok, or do you need open/close consistency, or what?

From David Howells.

Andreas Dilger points out that the first version of the extended statx
interface was posted June 29, 2010:

    https://www.spinics.net/lists/linux-fsdevel/msg33831.html

* 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  statx: Add a system call to make enhanced file info available

Pull block layer fixes from Jens Axboe:
 "A collection of fixes for this merge window, either fixes for existing
  issues, or parts that were waiting for acks to come in. This pull
  request contains:

   - Allocation of nvme queues on the right node from Shaohua.

     This was ready long before the merge window, but waiting on an ack
     from Bjorn on the PCI bit. Now that we have that, the three patches
     can go in.

   - Two fixes for blk-mq-sched with nvmeof, which uses hctx specific
     request allocations. This caused an oops. One part from Sagi, one
     part from Omar.

   - A loop partition scan deadlock fix from Omar, fixing a regression
     in this merge window.

   - A three-patch series from Keith, closing up a hole on clearing out
     requests on shutdown/resume.

   - A stable fix for nbd from Josef, fixing a leak of sockets.

   - Two fixes for a regression in this window from Jan, fixing a
     problem with one of his earlier patches dealing with queue vs bdi
     life times.

   - A fix for a regression with virtio-blk, causing an IO stall if
     scheduling is used. From me.

   - A fix for an io context lock ordering problem. From me"

* 'for-linus' of git://git.kernel.dk/linux-block:
  block: Move bdi_unregister() to del_gendisk()
  blk-mq: ensure that bd->last is always set correctly
  block: don't call ioc_exit_icq() with the queue lock held for blk-mq
  block: Initialize bd_bdi on inode initialization
  loop: fix LO_FLAGS_PARTSCAN hang
  nvme: Complete all stuck requests
  blk-mq: Provide freeze queue timeout
  blk-mq: Export blk_mq_freeze_queue_wait
  nbd: stop leaking sockets
  blk-mq: move update of tags->rqs to __blk_mq_alloc_request()
  blk-mq: kill blk_mq_set_alloc_data()
  blk-mq: make blk_mq_alloc_request_hctx() allocate a scheduler request
  blk-mq-sched: Allocate sched reserved tags as specified in the original queue tagset
  nvme: allocate nvme_queue in correct node
  PCI: add an API to get node from vector
  blk-mq: allocate blk_mq_tags and requests in correct node

Pull sched.h split-up from Ingo Molnar:
 "The point of these changes is to significantly reduce the
  <linux/sched.h> header footprint, to speed up the kernel build and to
  have a cleaner header structure.

  After these changes the new <linux/sched.h>'s typical preprocessed
  size goes down from a previous ~0.68 MB (~22K lines) to ~0.45 MB (~15K
  lines), which is around 40% faster to build on typical configs.

  Not much changed from the last version (-v2) posted three weeks ago: I
  eliminated quirks, backmerged fixes plus I rebased it to an upstream
  SHA1 from yesterday that includes most changes queued up in -next plus
  all sched.h changes that were pending from Andrew.

  I've re-tested the series both on x86 and on cross-arch defconfigs,
  and did a bisectability test at a number of random points.

  I tried to test as many build configurations as possible, but some
  build breakage is probably still left - but it should be mostly
  limited to architectures that have no cross-compiler binaries
  available on kernel.org, and non-default configurations"

* 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (146 commits)
  sched/headers: Clean up <linux/sched.h>
  sched/headers: Remove #ifdefs from <linux/sched.h>
  sched/headers: Remove the <linux/topology.h> include from <linux/sched.h>
  sched/headers, hrtimer: Remove the <linux/wait.h> include from <linux/hrtimer.h>
  sched/headers, x86/apic: Remove the <linux/pm.h> header inclusion from <asm/apic.h>
  sched/headers, timers: Remove the <linux/sysctl.h> include from <linux/timer.h>
  sched/headers: Remove <linux/magic.h> from <linux/sched/task_stack.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/init.h>
  sched/core: Remove unused prefetch_stack()
  sched/headers: Remove <linux/rculist.h> from <linux/sched.h>
  sched/headers: Remove the 'init_pid_ns' prototype from <linux/sched.h>
  sched/headers: Remove <linux/signal.h> from <linux/sched.h>
  sched/headers: Remove <linux/rwsem.h> from <linux/sched.h>
  sched/headers: Remove the runqueue_is_locked() prototype
  sched/headers: Remove <linux/sched.h> from <linux/sched/hotplug.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/debug.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/nohz.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/stat.h>
  sched/headers: Remove the <linux/gfp.h> include from <linux/sched.h>
  sched/headers: Remove <linux/rtmutex.h> from <linux/sched.h>
  ...

Merge tag 'linux-kselftest-4.11-rc1-urgent_fix' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull kselftest fix from Shuah Khan:
 "This update consists of an urgent fix for individual test build
  failures introduced in the 4.11-rc1 update"

* tag 'linux-kselftest-4.11-rc1-urgent_fix' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  selftests: lib.mk Fix individual test builds

If the security type specified using a mount option is not supported,
the SMB2 session setup code changes the security type to RawNTLMSSP. We
should instead fail the mount and return an error.

The patch changes the code for SMB2 to make it similar to the code used
for SMB1. Like in SMB1, we now use the global security flags to select
the security method to be used when no security method is specified and
to return an error when the requested auth method is not available.

For SMB2, we also use ntlmv2 as a synonym for nltmssp.
Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

Fix two minor sparse compile check warnings
Signed-off-by: Steve French <steve.french@primarydata.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>

Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode.  This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included.  The
following have been included:

 (1) Make the fields a consistent size on all arches and make them large.

 (2) Spare space, request flags and information flags are provided for
     future expansion.

 (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
     __s64).

 (4) Creation time: The SMB protocol carries the creation time, which could
     be exported by Samba, which will in turn help CIFS make use of
     FS-Cache as that can be used for coherency data (stx_btime).

     This is also specified in NFSv4 as a recommended attribute and could
     be exported by NFSD [Steve French].

 (5) Lightweight stat: Ask for just those details of interest, and allow a
     netfs (such as NFS) to approximate anything not of interest, possibly
     without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
     Dilger] (AT_STATX_DONT_SYNC).

 (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
     its cached attributes are up to date [Trond Myklebust]
     (AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

 (7) Data version number: Could be used by userspace NFS servers [Aneesh
     Kumar].

     Can also be used to modify fill_post_wcc() in NFSD which retrieves
     i_version directly, but has just called vfs_getattr().  It could get
     it from the kstat struct if it used vfs_xgetattr() instead.

     (There's disagreement on the exact semantics of a single field, since
     not all filesystems do this the same way).

 (8) BSD stat compatibility: Including more fields from the BSD stat such
     as creation time (st_btime) and inode generation number (st_gen)
     [Jeremy Allison, Bernd Schubert].

 (9) Inode generation number: Useful for FUSE and userspace NFS servers
     [Bernd Schubert].

     (This was asked for but later deemed unnecessary with the
     open-by-handle capability available and caused disagreement as to
     whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

     (No particular data were offered, but things like last backup
     timestamp, the data version number and the DOS archive bit would come
     into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
     filesystem can now say it doesn't support a standard stat feature if
     that isn't available, so if, for instance, inode numbers or UIDs don't
     exist or are fabricated locally...

     (This requires a separate system call - I have an fsinfo() call idea
     for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
     struct xstat [Steve French].

     (Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
     granularity of each of the times (NFSv4 time_delta) [Steve French].

     (Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value.  These could be translated to BSD's st_flags.
     Note that the Linux IOC flags are a mess and filesystems such as Ext4
     define flags that aren't in linux/fs.h, so translation in the kernel
     may be a necessity (or, possibly, we provide the filesystem type too).

     (Some attributes are made available in stx_attributes, but the general
     feeling was that the IOC flags were to ext[234]-specific and shouldn't
     be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
     Michael Kerrisk].

     (Deferred, probably to fsinfo.  Finding out if there's an ACL or
     seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

     (A __reserved field has been left in the statx_timestamp struct for
     this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

	int ret = statx(int dfd,
			const char *filename,
			unsigned int flags,
			unsigned int mask,
			struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat().  There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags.  There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

 (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
     respect.

 (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
     its attributes with the server - which might require data writeback to
     occur to get the timestamps correct.

 (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
     network filesystem.  The resulting values should be considered
     approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller.  The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat().  It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data.  This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

	struct statx_timestamp {
		__s64	tv_sec;
		__s32	tv_nsec;
		__s32	__reserved;
	};

	struct statx {
		__u32	stx_mask;
		__u32	stx_blksize;
		__u64	stx_attributes;
		__u32	stx_nlink;
		__u32	stx_uid;
		__u32	stx_gid;
		__u16	stx_mode;
		__u16	__spare0[1];
		__u64	stx_ino;
		__u64	stx_size;
		__u64	stx_blocks;
		__u64	__spare1[1];
		struct statx_timestamp	stx_atime;
		struct statx_timestamp	stx_btime;
		struct statx_timestamp	stx_ctime;
		struct statx_timestamp	stx_mtime;
		__u32	stx_rdev_major;
		__u32	stx_rdev_minor;
		__u32	stx_dev_major;
		__u32	stx_dev_minor;
		__u64	__spare2[14];
	};

The defined bits in request_mask and stx_mask are:

	STATX_TYPE		Want/got stx_mode & S_IFMT
	STATX_MODE		Want/got stx_mode & ~S_IFMT
	STATX_NLINK		Want/got stx_nlink
	STATX_UID		Want/got stx_uid
	STATX_GID		Want/got stx_gid
	STATX_ATIME		Want/got stx_atime{,_ns}
	STATX_MTIME		Want/got stx_mtime{,_ns}
	STATX_CTIME		Want/got stx_ctime{,_ns}
	STATX_INO		Want/got stx_ino
	STATX_SIZE		Want/got stx_size
	STATX_BLOCKS		Want/got stx_blocks
	STATX_BASIC_STATS	[The stuff in the normal stat struct]
	STATX_BTIME		Want/got stx_btime{,_ns}
	STATX_ALL		[All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution.  Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does.  The following
attributes map to FS_*_FL flags and are the same numerical value:

	STATX_ATTR_COMPRESSED		File is compressed by the fs
	STATX_ATTR_IMMUTABLE		File is marked immutable
	STATX_ATTR_APPEND		File is append-only
	STATX_ATTR_NODUMP		File is not to be dumped
	STATX_ATTR_ENCRYPTED		File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

	KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

	STATX_ATTR_AUTOMOUNT		Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

 (0) stx_dev_*, stx_blksize.

     These are local system information and are always available.

 (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
     stx_size, stx_blocks.

     These will be returned whether the caller asks for them or not.  The
     corresponding bits in stx_mask will be set to indicate whether they
     actually have valid values.

     If the caller didn't ask for them, then they may be approximated.  For
     example, NFS won't waste any time updating them from the server,
     unless as a byproduct of updating something requested.

     If the values don't actually exist for the underlying object (such as
     UID or GID on a DOS file), then the bit won't be set in the stx_mask,
     even if the caller asked for the value.  In such a case, the returned
     value will be a fabrication.

     Note that there are instances where the type might not be valid, for
     instance Windows reparse points.

 (2) stx_rdev_*.

     This will be set only if stx_mode indicates we're looking at a
     blockdev or a chardev, otherwise will be 0.

 (3) stx_btime.

     Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

	samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output.  Firstly, an NFS directory that crosses to
another FSID.  Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

	[root@andromeda ~]# /tmp/test-statx -A /warthog/data
	statx(/warthog/data) = 0
	results=7ff
	  Size: 4096            Blocks: 8          IO Block: 1048576  directory
	Device: 00:26           Inode: 1703937     Links: 125
	Access: (3777/drwxrwxrwx)  Uid:     0   Gid:  4041
	Access: 2016-11-24 09:02:12.219699527+0000
	Modify: 2016-11-17 10:44:36.225653653+0000
	Change: 2016-11-17 10:44:36.225653653+0000
	Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

	[root@andromeda ~]# /tmp/test-statx /warthog/data
	statx(/warthog/data) = 0
	results=7ff
	  Size: 4096            Blocks: 8          IO Block: 1048576  directory
	Device: 00:27           Inode: 2           Links: 125
	Access: (3777/drwxrwxrwx)  Uid:     0   Gid:  4041
	Access: 2016-11-24 09:02:12.219699527+0000
	Modify: 2016-11-17 10:44:36.225653653+0000
	Change: 2016-11-17 10:44:36.225653653+0000
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull turbostat utility updates from Rafael Wysocki:
 "Power management turbostat utility updates.

  These update turbostat significantly and in particular:

   - default output is now verbose, --debug is no longer required to get
     all counters. As a result, some options have been added to specify
     exactly what output is wanted.

   - added --quiet to skip system configuration output

   - added --list, --show and --hide parameters

   - added --cpu parameter

   - enhanced Baytrail SoC support

   - added Gemini Lake SoC support

   - added sysfs C-state columns

  Also the symbol definitions in arch/x86/include/asm/intel-family.h and
  arch/x86/include/asm/msr-index.h are updated and the intel_idle and
  intel_pstate drivers are modified to use the updated symbols.

  Credits to Len Brown for all of these changes"

* tag 'pm-turbostat-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (44 commits)
  tools/power turbostat: version 17.02.24
  tools/power turbostat: bugfix: --add u32 was printed as u64
  tools/power turbostat: show error on exec
  tools/power turbostat: dump p-state software config
  tools/power turbostat: show package number, even without --debug
  tools/power turbostat: support "--hide C1" etc.
  tools/power turbostat: move --Package and --processor into the --cpu option
  tools/power turbostat: turbostat.8 update
  tools/power turbostat: update --list feature
  tools/power turbostat: use wide columns to display large numbers
  tools/power turbostat: Add --list option to show available header names
  tools/power turbostat: fix zero IRQ count shown in one-shot command mode
  tools/power turbostat: add --cpu parameter
  tools/power turbostat: print sysfs C-state stats
  tools/power turbostat: extend --add option to accept /sys path
  tools/power turbostat: skip unused counters on BDX
  tools/power turbostat: fix decoding for GLM, DNV, SKX turbo-ratio limits
  tools/power turbostat: skip unused counters on SKX
  tools/power turbostat: Denverton: use HW CC1 counter, skip C3, C7
  tools/power turbostat: initial Gemini Lake SOC support
  ...

Pull ACPI fix from Rafael Wysocki:
 "This fixes an apparent, but actually artificial, resource conflict
  between the ACPI NVS memory region and the ACPI BERT (Boot Error
  Record Table) address range (Huang Ying)"

* tag 'acpi-extra-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: APEI: Fix BERT resources conflict with ACPI NVS area

Pull more power management updates deom Rafael Wysocki:
 "These fix two bugs introduced by recent power management updates (in
  the cpuidle menu governor and intel_pstate) and a few other issues,
  clean up things and remove unused code.

  Specifics:

   - Fix for a cpuidle menu governor problem that started to take an
     unnecessary spinlock after one of the recent updates and that did
     not play well with the RT patch (Rafael Wysocki).

   - Fix for the new intel_pstate operation mode switching feature added
     recently that did not reinitialize P-state limits properly when
     switching operation modes (Rafael Wysocki).

   - Removal of unused global notifiers from the PM QoS framework
     (Viresh Kumar).

   - Generic power domains framework update to make it handle
     asynchronous invocations of PM callbacks in the "noirq" phases of
     system suspend/hibernation correctly (Ulf Hansson).

   - Two hibernation core cleanups (Rafael Wysocki).

   - intel_idle cleanup related to the sysfs interface (Len Brown).

   - Off-by-one bug fix in the OPP (Operating Performance Points)
     framework (Andrzej Hajda).

   - OPP framework's documentation fix (Viresh Kumar).

   - cpufreq qoriq driver cleanup (Tang Yuantian).

   - Fixes for typos in comments in the device runtime PM framework
     (Christophe Jaillet)"

* tag 'pm-extra-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM / OPP: Documentation: Fix opp-microvolt in examples
  intel_idle: stop exposing platform acronyms in sysfs
  cpufreq: intel_pstate: Fix limits issue with operation mode switching
  PM / hibernate: Define pr_fmt() and use pr_*() instead of printk()
  PM / hibernate: Untangle power_down()
  cpuidle: menu: Avoid taking spinlock for accessing QoS values
  PM / QoS: Remove global notifiers
  PM / runtime: Fix some typos
  cpufreq: qoriq: clean up unused code
  PM / OPP: fix off-by-one bug in dev_pm_opp_get_max_volt_latency loop
  PM / Domains: Power off masters immediately in the power off sequence
  PM / Domains: Rename is_async to one_dev_on for genpd_power_off()
  PM / Domains: Move genpd_power_off() above genpd_power_on()

Now that <linux/sched.h> dependencies have been sorted out,
do various trivial cleanups:

 - remove unnecessary structure predeclarations
 - fix various typos
 - update comments where necessary
 - remove pointless comments
 - use consistent types
 - tabulate consistently
 - use a consistent comment style
 - clean up the header section a bit
 - use a consistent style of a single field per line
 - remove line-breaks where they make the code look worse
 - etc ...

No change in functionality.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

We can remove two pairs of #ifdefs by defining structures in a smarter way.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

It's used only by a single (rarely used) inline function (task_node(p)),
which we can move to <linux/sched/topology.h>.

( Add <linux/nodemask.h>, because we rely on that. )
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

In our quest to simplify <linux/sched.h>'s header dependencies, remove
the <linux/wait.h> inclusion from <linux/hrtimer.h> - which does
not appear to be necessary, as hrtimer.h does not use waitqueues.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

We want to simplify <linux/sched.h>'s header dependencies, but one
roadblock to that is <asm/apic.h>'s inclusion of pm.h,
which brings in other, problematic headers.

Remove it, as it appears to be entirely spurious, apic.h does not
actually make use of any PM facilities.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

So we want to simplify <linux/sched.h>'s header dependencies, but one
roadblock of that is <linux/timer.h>'s inclusion of sysctl.h,
which brings in other, problematic headers.

Note that timer.h's inclusion of sysctl.h can be avoided if we
pre-declare ctl_table - so do that.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

It's not used by any of the scheduler methods, but <linux/sched/task_stack.h>
needs it to pick up STACK_END_MAGIC.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>