Commit 80e96c54 ("dm thin: do not allow thin device activation
while pool is suspended") delayed the initialization of a new thin
device's refcount and completion until after this new thin was added
to the pool's active_thins list and the pool lock is released.  This
opens a race with a worker thread that walks the list and calls
thin_get/put, noticing that the refcount goes to 0 and calling
complete, freezing up the system and giving the oops below:

 kernel: BUG: unable to handle kernel NULL pointer dereference at           (null)
 kernel: IP: [<ffffffff810d360b>] __wake_up_common+0x2b/0x90

 kernel: Call Trace:
 kernel: [<ffffffff810d3683>] __wake_up_locked+0x13/0x20
 kernel: [<ffffffff810d3dc7>] complete+0x37/0x50
 kernel: [<ffffffffa0595c50>] thin_put+0x20/0x30 [dm_thin_pool]
 kernel: [<ffffffffa059aab7>] do_worker+0x667/0x870 [dm_thin_pool]
 kernel: [<ffffffff816a8a4c>] ? __schedule+0x3ac/0x9a0
 kernel: [<ffffffff810b1aef>] process_one_work+0x14f/0x400
 kernel: [<ffffffff810b206b>] worker_thread+0x6b/0x490
 kernel: [<ffffffff810b2000>] ? rescuer_thread+0x260/0x260
 kernel: [<ffffffff810b6a7b>] kthread+0xdb/0x100
 kernel: [<ffffffff810b69a0>] ? kthread_create_on_node+0x170/0x170
 kernel: [<ffffffff816ad7ec>] ret_from_fork+0x7c/0xb0
 kernel: [<ffffffff810b69a0>] ? kthread_create_on_node+0x170/0x170

Set the thin device's initial refcount and initialize the completion
before adding it to the pool's active_thins list in thin_ctr().
Signed-off-by: Marc Dionne <marc.dionne@your-file-system.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Discard bios and thin device deletion have the potential to release data
blocks.  If the thin-pool is in out-of-data-space mode, and blocks were
released, transition the thin-pool back to full write mode.

The correct time to do this is just after the thin-pool metadata commit.
It cannot be done before the commit because the space maps will not
allow immediate reuse of the data blocks in case there's a rollback
following power failure.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org

When the pool was in PM_OUT_OF_SPACE mode its process_prepared_discard
function pointer was incorrectly being set to
process_prepared_discard_passdown rather than process_prepared_discard.

This incorrect function pointer meant the discard was being passed down,
but not effecting the mapping.  As such any discard that was issued, in
an attempt to reclaim blocks, would not successfully free data space.
Reported-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org

Pull core block fix from Jens Axboe:
 "Jan reported a problem this morning with a crash in blk-mq, and after
  looking over the recent changes, it's obvious that the blk-mq-tag
  waitqueue handling change is buggy.  We could end up _not_ doing
  finish_wait() before switching to a new waitqueue, thus corrupting the
  wait task list"

* 'for-linus' of git://git.kernel.dk/linux-block:
  Revert "blk-mq: Micro-optimize bt_get()"

Pull rpmsg update from Ohad Ben-Cohen:
 "A single patch from Suman Anna which makes rpmsg use less buffers when
  small vrings are being used"

* tag 'rpmsg-3.19-next' of git://git.kernel.org/pub/scm/linux/kernel/git/ohad/rpmsg:
  rpmsg: use less buffers when vrings are small

Pull drm updates from Dave Airlie:
 "Highlights:

   - AMD KFD driver merge

     This is the AMD HSA interface for exposing a lowlevel interface for
     GPGPU use.  They have an open source userspace built on top of this
     interface, and the code looks as good as it was going to get out of
     tree.

   - Initial atomic modesetting work

     The need for an atomic modesetting interface to allow userspace to
     try and send a complete set of modesetting state to the driver has
     arisen, and been suffering from neglect this past year.  No more,
     the start of the common code and changes for msm driver to use it
     are in this tree.  Ongoing work to get the userspace ioctl finished
     and the code clean will probably wait until next kernel.

   - DisplayID 1.3 and tiled monitor exposed to userspace.

     Tiled monitor property is now exposed for userspace to make use of.

   - Rockchip drm driver merged.

   - imx gpu driver moved out of staging

  Other stuff:

   - core:
        panel - MIPI DSI + new panels.
        expose suggested x/y properties for virtual GPUs

   - i915:
        Initial Skylake (SKL) support
        gen3/4 reset work
        start of dri1/ums removal
        infoframe tracking
        fixes for lots of things.

   - nouveau:
        tegra k1 voltage support
        GM204 modesetting support
        GT21x memory reclocking work

   - radeon:
        CI dpm fixes
        GPUVM improvements
        Initial DPM fan control

   - rcar-du:
        HDMI support added
        removed some support for old boards
        slave encoder driver for Analog Devices adv7511

   - exynos:
        Exynos4415 SoC support

   - msm:
        a4xx gpu support
        atomic helper conversion

   - tegra:
        iommu support
        universal plane support
        ganged-mode DSI support

   - sti:
        HDMI i2c improvements

   - vmwgfx:
        some late fixes.

   - qxl:
        use suggested x/y properties"

* 'drm-next' of git://people.freedesktop.org/~airlied/linux: (969 commits)
  drm: sti: fix module compilation issue
  drm/i915: save/restore GMBUS freq across suspend/resume on gen4
  drm: sti: correctly cleanup CRTC and planes
  drm: sti: add HQVDP plane
  drm: sti: add cursor plane
  drm: sti: enable auxiliary CRTC
  drm: sti: fix delay in VTG programming
  drm: sti: prepare sti_tvout to support auxiliary crtc
  drm: sti: use drm_crtc_vblank_{on/off} instead of drm_vblank_{on/off}
  drm: sti: fix hdmi avi infoframe
  drm: sti: remove event lock while disabling vblank
  drm: sti: simplify gdp code
  drm: sti: clear all mixer control
  drm: sti: remove gpio for HDMI hot plug detection
  drm: sti: allow to change hdmi ddc i2c adapter
  drm/doc: Document drm_add_modes_noedid() usage
  drm/i915: Remove '& 0xffff' from the mask given to WA_REG()
  drm/i915: Invert the mask and val arguments in wa_add() and WA_REG()
  drm: Zero out DRM object memory upon cleanup
  drm/i915/bdw: Fix the write setting up the WIZ hashing mode
  ...

The VM_FAULT_RETRY handling was confusing and incorrect for the case of
returning to kernel mode.  We need to handle the exception table fixup
if we return to kernel mode due to a fatal signal - it will basically
look to the kernel user mode access like the access failed due to the VM
going away from udner it.  Which is correct - the process is dying - and
avoids the whole "repeat endless kernel page faults" case.

Handling the VM_FAULT_RETRY early and in just one place also simplifies
the mmap_sem handling, since once we've taken care of VM_FAULT_RETRY we
know that we can just drop the lock.  The remaining accounting and
possible error handling is thread-local and does not need the mmap_sem.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This replaces four copies in various stages of mm_fault_error() handling
with just a single one.  It will also allow for more natural placement
of the unlocking after some further cleanup.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This reverts commit 52f7eb94.

The optimization is only really safe for a single queue, otherwise
'bs' and 'bt' can indeed change, and if we don't do a finish_wait()
for each loop, we'll potentially change the wait structure and
corrupt task wait list.
Reported-by: Jan Kara <jack@suse.cz>

When compiling in module some symbol aren't missing,
export them correctly.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Pull security layer updates from James Morris:
 "In terms of changes, there's general maintenance to the Smack,
  SELinux, and integrity code.

  The IMA code adds a new kconfig option, IMA_APPRAISE_SIGNED_INIT,
  which allows IMA appraisal to require signatures.  Support for reading
  keys from rootfs before init is call is also added"

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (23 commits)
  selinux: Remove security_ops extern
  security: smack: fix out-of-bounds access in smk_parse_smack()
  VFS: refactor vfs_read()
  ima: require signature based appraisal
  integrity: provide a hook to load keys when rootfs is ready
  ima: load x509 certificate from the kernel
  integrity: provide a function to load x509 certificate from the kernel
  integrity: define a new function integrity_read_file()
  Security: smack: replace kzalloc with kmem_cache for inode_smack
  Smack: Lock mode for the floor and hat labels
  ima: added support for new kernel cmdline parameter ima_template_fmt
  ima: allocate field pointers array on demand in template_desc_init_fields()
  ima: don't allocate a copy of template_fmt in template_desc_init_fields()
  ima: display template format in meas. list if template name length is zero
  ima: added error messages to template-related functions
  ima: use atomic bit operations to protect policy update interface
  ima: ignore empty and with whitespaces policy lines
  ima: no need to allocate entry for comment
  ima: report policy load status
  ima: use path names cache
  ...

Pull char/misc driver updates from Greg KH:
 "Here's the big char/misc driver update for 3.19-rc1

  Lots of little things all over the place in different drivers, and a
  new subsystem, "coresight" has been added.  Full details are in the
  shortlog"

* tag 'char-misc-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (73 commits)
  parport: parport_pc, do not remove parent devices early
  spmi: Remove shutdown/suspend/resume kernel-doc
  carma-fpga-program: drop videobuf dependency
  carma-fpga: drop videobuf dependency
  carma-fpga-program.c: fix compile errors
  i8k: Fix temperature bug handling in i8k_get_temp()
  cxl: Name interrupts in /proc/interrupt
  CXL: Return error to PSL if IRQ demultiplexing fails & print clearer warning
  coresight-replicator: remove .owner field for driver
  coresight: fixed comments in coresight.h
  coresight: fix typo in comment in coresight-priv.h
  coresight: bindings for coresight drivers
  coresight: Adding ABI documentation
  w1: support auto-load of w1_bq27000 module.
  w1: avoid potential u16 overflow
  cn: verify msg->len before making callback
  mei: export fw status registers through sysfs
  mei: read and print all six FW status registers
  mei: txe: add cherrytrail device id
  mei: kill cached host and me csr values
  ...

Merge tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core update from Greg KH:
 "Here's the set of driver core patches for 3.19-rc1.

  They are dominated by the removal of the .owner field in platform
  drivers.  They touch a lot of files, but they are "simple" changes,
  just removing a line in a structure.

  Other than that, a few minor driver core and debugfs changes.  There
  are some ath9k patches coming in through this tree that have been
  acked by the wireless maintainers as they relied on the debugfs
  changes.

  Everything has been in linux-next for a while"

* tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (324 commits)
  Revert "ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries"
  fs: debugfs: add forward declaration for struct device type
  firmware class: Deletion of an unnecessary check before the function call "vunmap"
  firmware loader: fix hung task warning dump
  devcoredump: provide a one-way disable function
  device: Add dev_<level>_once variants
  ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries
  ath: use seq_file api for ath9k debugfs files
  debugfs: add helper function to create device related seq_file
  drivers/base: cacheinfo: remove noisy error boot message
  Revert "core: platform: add warning if driver has no owner"
  drivers: base: support cpu cache information interface to userspace via sysfs
  drivers: base: add cpu_device_create to support per-cpu devices
  topology: replace custom attribute macros with standard DEVICE_ATTR*
  cpumask: factor out show_cpumap into separate helper function
  driver core: Fix unbalanced device reference in drivers_probe
  driver core: fix race with userland in device_add()
  sysfs/kernfs: make read requests on pre-alloc files use the buffer.
  sysfs/kernfs: allow attributes to request write buffer be pre-allocated.
  fs: sysfs: return EGBIG on write if offset is larger than file size
  ...

Pull tty/serial driver updates from Greg KH:
 "Here's the big tty/serial driver update for 3.19-rc1.

  There are a number of TTY core changes/fixes in here from Peter Hurley
  that have all been teted in linux-next for a long time now.  There are
  also the normal serial driver updates as well, full details in the
  changelog below"

* tag 'tty-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (219 commits)
  serial: pxa: hold port.lock when reporting modem line changes
  tty-hvsi_lib: Deletion of an unnecessary check before the function call "tty_kref_put"
  tty: Deletion of unnecessary checks before two function calls
  n_tty: Fix read_buf race condition, increment read_head after pushing data
  serial: of-serial: add PM suspend/resume support
  Revert "serial: of-serial: add PM suspend/resume support"
  Revert "serial: of-serial: fix up PM ops on no_console_suspend and port type"
  serial: 8250: don't attempt a trylock if in sysrq
  serial: core: Add big-endian iotype
  serial: samsung: use port->fifosize instead of hardcoded values
  serial: samsung: prefer to use fifosize from driver data
  serial: samsung: fix style problems
  serial: samsung: wait for transfer completion before clock disable
  serial: icom: fix error return code
  serial: tegra: clean up tty-flag assignments
  serial: Fix io address assign flow with Fintek PCI-to-UART Product
  serial: mxs-auart: fix tx_empty against shift register
  serial: mxs-auart: fix gpio change detection on interrupt
  serial: mxs-auart: Fix mxs_auart_set_ldisc()
  serial: 8250_dw: Use 64-bit access for OCTEON.
  ...

Pull USB updates from Greg KH:
 "Here's the big set of USB and PHY patches for 3.19-rc1.

  The normal churn in the USB gadget area is in here, as well as xhci
  and other individual USB driver updates.  The PHY tree is also in
  here, as there were dependancies on the USB tree.

  All of these have been in linux-next"

* tag 'usb-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (351 commits)
  arm: omap3: twl: remove usb phy init data
  usbip: fix error handling in stub_probe()
  usb: gadget: udc: missing curly braces
  USB: mos7720: delete some unneeded code
  wusb: replace memset by memzero_explicit
  usbip: remove unneeded structure
  usb: xhci: fix comment for PORT_DEV_REMOVE
  xhci: don't use the same variable for stopped and halted rings current TD
  xhci: clear extra bits from slot context when setting max exit latency
  xhci: cleanup finish_td function
  USB: adutux: NULL dereferences on disconnect
  usb: chipidea: fix platform_no_drv_owner.cocci warnings
  usb: chipidea: Fixed a few typos in comments
  Documentation: bindings: add doc for the USB2 ChipIdea USB driver
  usb: chipidea: add a usb2 driver for ci13xxx
  usb: chipidea: fix phy handling
  usb: chipidea: remove duplicate dev_set_drvdata for host_start
  usb: chipidea: parameter 'mode' isn't needed for hw_device_reset
  usb: chipidea: add controller reset API
  usb: chipidea: remove flag CI_HDRC_REQUIRE_TRANSCEIVER
  ...

Pull squashfs update from Phillip Lougher:
 "These patches optionally add LZ4 compression support to Squashfs.

  LZ4 is a lightweight compression algorithm which can be used on
  embedded systems to reduce CPU and memory overhead (in comparison to
  the standard zlib compression).

  These patches add the wrapper code to allow Squashfs to use the
  existing LZ4 decompression code, and the necessary configuration
  option"

* tag 'squashfs-updates' of git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-next:
  Squashfs: Add LZ4 compression configuration option
  Squashfs: add LZ4 compression support

Pull take two of the GPIO updates:
 "Same stuff as last time, now with a fixup patch for the previous
  compile error plus I ran a few extra rounds of compile-testing.

  This is the bulk of GPIO changes for the v3.19 series:

   - A new API that allows setting more than one GPIO at the time.  This
     is implemented for the new descriptor-based API only and makes it
     possible to e.g. toggle a clock and data line at the same time, if
     the hardware can do this with a single register write.  Both
     consumers and drivers need new calls, and the core will fall back
     to driving individual lines where needed.  Implemented for the
     MPC8xxx driver initially

   - Patched the mdio-mux-gpio and the serial mctrl driver that drives
     modems to use the new multiple-setting API to set several signals
     simultaneously

   - Get rid of the global GPIO descriptor array, and instead allocate
     descriptors dynamically for each GPIO on a certain GPIO chip.  This
     moves us closer to getting rid of the limitation of using the
     global, static GPIO numberspace

   - New driver and device tree bindings for 74xx ICs

   - New driver and device tree bindings for the VF610 Vybrid

   - Support the RCAR r8a7793 and r8a7794

   - Guidelines for GPIO device tree bindings trying to get things a bit
     more strict with the advent of combined device properties

   - Suspend/resume support for the MVEBU driver

   - A slew of minor fixes and improvements"

* tag 'gpio-v3.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (33 commits)
  gpio: mcp23s08: fix up compilation error
  gpio: pl061: document gpio-ranges property for bindings file
  gpio: pl061: hook request if gpio-ranges avaiable
  gpio: mcp23s08: Add option to configure IRQ output polarity as active high
  gpio: fix deferred probe detection for legacy API
  serial: mctrl_gpio: use gpiod_set_array function
  mdio-mux-gpio: Use GPIO descriptor interface and new gpiod_set_array function
  gpio: remove const modifier from gpiod_get_direction()
  gpio: remove gpio_descs global array
  gpio: mxs: implement get_direction callback
  gpio: em: Use dynamic allocation of GPIOs
  gpio: Check if base is positive before calling gpio_is_valid()
  gpio: mcp23s08: Add simple IRQ support for SPI devices
  gpio: mcp23s08: request a shared interrupt
  gpio: mcp23s08: Do not free unrequested interrupt
  gpio: rcar: Add r8a7793 and r8a7794 support
  gpio-mpc8xxx: add mpc8xxx_gpio_set_multiple function
  gpiolib: allow simultaneous setting of multiple GPIO outputs
  gpio: mvebu: add suspend/resume support
  gpio: gpio-davinci: remove duplicate check on resource
  ..

Pull aio updates from Benjamin LaHaise.

* git://git.kvack.org/~bcrl/aio-next:
  aio: Skip timer for io_getevents if timeout=0
  aio: Make it possible to remap aio ring

Pull i2c updates from Wolfram Sang:
 "For 3.19, the I2C subsystem has to offer special candy this time.
  Right in time for Christmas :)

   - I2C slave framework: finally, a generic mechanism for Linux being
     an I2C slave (if the bus driver supports that).  Docs are still
     missing but will come later this cycle, the code is good enough to
     go.
   - I2C muxes represent their topology in sysfs much more detailed.
     This will help users to navigate around much easier.
   - irq population of i2c clients is now done at probe time, not device
     creation time, to have better support for deferred probing.
   - new drivers for Imagination SCB, Amlogic Meson
   - DMA support added for Freescale IMX, Renesas SHMobile
   - slightly bigger driver updates to OMAP, i801, AT91, and rk3x
     (mostly quirk handling, timing updates, and using better kernel
     interfaces)
   - eeprom driver can now write with byte-access (very slow, but OK to
     have)
   - and the bunch of smaller fixes, cleanups, ID updates..."

* 'i2c/for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (56 commits)
  i2c: sh_mobile: remove unneeded DMA mask
  i2c: rcar: add slave support
  i2c: slave-eeprom: add eeprom simulator driver
  i2c: core changes for slave support
  MAINTAINERS: add I2C dt bindings also to I2C realm
  i2c: designware: Fix falling time bindings doc
  i2c: davinci: switch to use platform_get_irq
  Documentation: i2c: Use PM ops instead of legacy suspend/resume
  i2c: sh_mobile: optimize irq entry
  i2c: pxa: add support for SCCB devices
  omap: i2c: don't check bus state IP rev3.3 and earlier
  i2c: s3c2410: Handle i2c sys_cfg register in i2c driver
  i2c: rk3x: add Kconfig dependency on COMMON_CLK
  i2c: omap: add notes related to i2c multimaster mode
  i2c: omap: don't reset controller if Arbitration Lost detected
  i2c: omap: implement workaround for handling invalid BB-bit values
  i2c: omap: cleanup register definitions
  i2c: rk3x: handle dynamic clock rate changes correctly
  i2c: at91: enable probe deferring on dma channel request
  i2c: at91: remove legacy DMA support
  ...

Pull md updates from Neil Brown:
 "Three fixes for md.

   I did have a largish set of locking changes queued, but late testing
  showed they weren't quite as stable as I thought and while I fixed
  what I found, I decided it safer to delay them a release ...
  particularly as I'll be AFK for a few weeks.  So expect a larger batch
  next time :-)"

* tag 'md/3.19' of git://neil.brown.name/md:
  md: Check MD_RECOVERY_RUNNING as well as ->sync_thread.
  md: fix semicolon.cocci warnings
  md/raid5: fetch_block must fetch all the blocks handle_stripe_dirtying wants.

Pull x86 fixes from Ingo Molnar:
 "Misc fixes (mainly Andy's TLS fixes), plus a cleanup"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/tls: Disallow unusual TLS segments
  x86/tls: Validate TLS entries to protect espfix
  MAINTAINERS: Add me as x86 VDSO submaintainer
  x86/asm: Unify segment selector defines
  x86/asm: Guard against building the 32/64-bit versions of the asm-offsets*.c file directly
  x86_64, switch_to(): Load TLS descriptors before switching DS and ES
  x86/mm: Use min() instead of min_t() in the e820 printout code
  x86/mm: Fix zone ranges boot printout
  x86/doc: Update documentation after file shuffling

Users have no business installing custom code segments into the
GDT, and segments that are not present but are otherwise valid
are a historical source of interesting attacks.

For completeness, block attempts to set the L bit.  (Prior to
this patch, the L bit would have been silently dropped.)

This is an ABI break.  I've checked glibc, musl, and Wine, and
none of them look like they'll have any trouble.

Note to stable maintainers: this is a hardening patch that fixes
no known bugs.  Given the possibility of ABI issues, this
probably shouldn't be backported quickly.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: stable@vger.kernel.org # optional
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: security@kernel.org <security@kernel.org>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Installing a 16-bit RW data segment into the GDT defeats espfix.
AFAICT this will not affect glibc, Wine, or dosemu at all.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: stable@vger.kernel.org
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: security@kernel.org <security@kernel.org>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Here goes... :)
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1042001e502f8e0deb0edfeeac209b68378650cf.1418430292.git.luto@amacapital.netSigned-off-by: Ingo Molnar <mingo@kernel.org>

In this case, it is basically a polling. Let's not involve timer at all
because that would hurt performance for application event loops.

In an arbitrary test I've done, io_getevents syscall elapsed time
reduces from 50000+ nanoseconds to a few hundereds.
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>

There are actually two issues this patch addresses. Let me start with
the one I tried to solve in the beginning.

So, in the checkpoint-restore project (criu) we try to dump tasks'
state and restore one back exactly as it was. One of the tasks' state
bits is rings set up with io_setup() call. There's (almost) no problems
in dumping them, there's a problem restoring them -- if I dump a task
with aio ring originally mapped at address A, I want to restore one
back at exactly the same address A. Unfortunately, the io_setup() does
not allow for that -- it mmaps the ring at whatever place mm finds
appropriate (it calls do_mmap_pgoff() with zero address and without
the MAP_FIXED flag).

To make restore possible I'm going to mremap() the freshly created ring
into the address A (under which it was seen before dump). The problem is
that the ring's virtual address is passed back to the user-space as the
context ID and this ID is then used as search key by all the other io_foo()
calls. Reworking this ID to be just some integer doesn't seem to work, as
this value is already used by libaio as a pointer using which this library
accesses memory for aio meta-data.

So, to make restore work we need to make sure that

a) ring is mapped at desired virtual address
b) kioctx->user_id matches this value

Having said that, the patch makes mremap() on aio region update the
kioctx's user_id and mmap_base values.

Here appears the 2nd issue I mentioned in the beginning of this mail.
If (regardless of the C/R dances I do) someone creates an io context
with io_setup(), then mremap()-s the ring and then destroys the context,
the kill_ioctx() routine will call munmap() on wrong (old) address.
This will result in a) aio ring remaining in memory and b) some other
vma get unexpectedly unmapped.

What do you think?
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>

Pull block layer driver updates from Jens Axboe:

 - NVMe updates:
        - The blk-mq conversion from Matias (and others)

        - A stack of NVMe bug fixes from the nvme tree, mostly from Keith.

        - Various bug fixes from me, fixing issues in both the blk-mq
          conversion and generic bugs.

        - Abort and CPU online fix from Sam.

        - Hot add/remove fix from Indraneel.

 - A couple of drbd fixes from the drbd team (Andreas, Lars, Philipp)

 - With the generic IO stat accounting from 3.19/core, converting md,
   bcache, and rsxx to use those.  From Gu Zheng.

 - Boundary check for queue/irq mode for null_blk from Matias.  Fixes
   cases where invalid values could be given, causing the device to hang.

 - The xen blkfront pull request, with two bug fixes from Vitaly.

* 'for-3.19/drivers' of git://git.kernel.dk/linux-block: (56 commits)
  NVMe: fix race condition in nvme_submit_sync_cmd()
  NVMe: fix retry/error logic in nvme_queue_rq()
  NVMe: Fix FS mount issue (hot-remove followed by hot-add)
  NVMe: fix error return checking from blk_mq_alloc_request()
  NVMe: fix freeing of wrong request in abort path
  xen/blkfront: remove redundant flush_op
  xen/blkfront: improve protection against issuing unsupported REQ_FUA
  NVMe: Fix command setup on IO retry
  null_blk: boundary check queue_mode and irqmode
  block/rsxx: use generic io stats accounting functions to simplify io stat accounting
  md: use generic io stats accounting functions to simplify io stat accounting
  drbd: use generic io stats accounting functions to simplify io stat accounting
  md/bcache: use generic io stats accounting functions to simplify io stat accounting
  NVMe: Update module version major number
  NVMe: fail pci initialization if the device doesn't have any BARs
  NVMe: add ->exit_hctx() hook
  NVMe: make setup work for devices that don't do INTx
  NVMe: enable IO stats by default
  NVMe: nvme_submit_async_admin_req() must use atomic rq allocation
  NVMe: replace blk_put_request() with blk_mq_free_request()
  ...

Pull block driver core update from Jens Axboe:
 "This is the pull request for the core block IO changes for 3.19.  Not
  a huge round this time, mostly lots of little good fixes:

   - Fix a bug in sysfs blktrace interface causing a NULL pointer
     dereference, when enabled/disabled through that API.  From Arianna
     Avanzini.

   - Various updates/fixes/improvements for blk-mq:

        - A set of updates from Bart, mostly fixing buts in the tag
          handling.

        - Cleanup/code consolidation from Christoph.

        - Extend queue_rq API to be able to handle batching issues of IO
          requests. NVMe will utilize this shortly. From me.

        - A few tag and request handling updates from me.

        - Cleanup of the preempt handling for running queues from Paolo.

        - Prevent running of unmapped hardware queues from Ming Lei.

        - Move the kdump memory limiting check to be in the correct
          location, from Shaohua.

        - Initialize all software queues at init time from Takashi. This
          prevents a kobject warning when CPUs are brought online that
          weren't online when a queue was registered.

   - Single writeback fix for I_DIRTY clearing from Tejun.  Queued with
     the core IO changes, since it's just a single fix.

   - Version X of the __bio_add_page() segment addition retry from
     Maurizio.  Hope the Xth time is the charm.

   - Documentation fixup for IO scheduler merging from Jan.

   - Introduce (and use) generic IO stat accounting helpers for non-rq
     drivers, from Gu Zheng.

   - Kill off artificial limiting of max sectors in a request from
     Christoph"

* 'for-3.19/core' of git://git.kernel.dk/linux-block: (26 commits)
  bio: modify __bio_add_page() to accept pages that don't start a new segment
  blk-mq: Fix uninitialized kobject at CPU hotplugging
  blktrace: don't let the sysfs interface remove trace from running list
  blk-mq: Use all available hardware queues
  blk-mq: Micro-optimize bt_get()
  blk-mq: Fix a race between bt_clear_tag() and bt_get()
  blk-mq: Avoid that __bt_get_word() wraps multiple times
  blk-mq: Fix a use-after-free
  blk-mq: prevent unmapped hw queue from being scheduled
  blk-mq: re-check for available tags after running the hardware queue
  blk-mq: fix hang in bt_get()
  blk-mq: move the kdump check to blk_mq_alloc_tag_set
  blk-mq: cleanup tag free handling
  blk-mq: use 'nr_cpu_ids' as highest CPU ID count for hwq <-> cpu map
  blk: introduce generic io stat accounting help function
  blk-mq: handle the single queue case in blk_mq_hctx_next_cpu
  genhd: check for int overflow in disk_expand_part_tbl()
  blk-mq: add blk_mq_free_hctx_request()
  blk-mq: export blk_mq_free_request()
  blk-mq: use get_cpu/put_cpu instead of preempt_disable/preempt_enable
  ...

Merge tag 'trace-seq-buf-3.19-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixlet from Steven Rostedt:
 "Remove unnecessary preempt_disable in printk()"

* tag 'trace-seq-buf-3.19-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  printk: Do not disable preemption for accessing printk_func

Pull tracing fixes from Steven Rostedt:
 "Here's two fixes:

  1) Discovered by Fengguang Wu's tests.  I changed the parameters to
     the function graph x86 prepare_ftrace_return call but forgot to
     update the call from entry_32 (i386 version).  This patch corrects
     that.

  2) I was tracing some code and found that the sched_switch tracepoint
     was showing tasks in the INTERRUPTIBLE state as RUNNING.  This was
     due to the updates to convert preempt_count into a per_cpu
     variable.  The tracepoint logic was made to use the tasks
     saved_preempt_count which could hold a stale "PREEMPT_ACTIVE",
     instead of using the current preempt_count() call"

* tag 'trace-fixes-v3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing/sched: Check preempt_count() for current when reading task->state
  ftrace/x86: Update i386 call to prepare_ftrace_return()

Pull audit updates from Paul Moore:
 "Two small patches from the audit next branch; only one of which has
  any real significant code changes, the other is simply a MAINTAINERS
  update for audit.

  The single code patch is pretty small and rather straightforward, it
  changes the audit "version" number reported to userspace from an
  integer to a bitmap which is used to indicate the functionality of the
  running kernel.  This really doesn't have much impact on the kernel,
  but it will make life easier for the audit userspace folks.

  Thankfully we were still on a version number which allowed us to do
  this without breaking userspace"

* 'upstream' of git://git.infradead.org/users/pcmoore/audit:
  audit: convert status version to a feature bitmap
  audit: add Paul Moore to the MAINTAINERS entry

Pull crypto update from Herbert Xu:
 - The crypto API is now documented :)
 - Disallow arbitrary module loading through crypto API.
 - Allow get request with empty driver name through crypto_user.
 - Allow speed testing of arbitrary hash functions.
 - Add caam support for ctr(aes), gcm(aes) and their derivatives.
 - nx now supports concurrent hashing properly.
 - Add sahara support for SHA1/256.
 - Add ARM64 version of CRC32.
 - Misc fixes.

* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (77 commits)
  crypto: tcrypt - Allow speed testing of arbitrary hash functions
  crypto: af_alg - add user space interface for AEAD
  crypto: qat - fix problem with coalescing enable logic
  crypto: sahara - add support for SHA1/256
  crypto: sahara - replace tasklets with kthread
  crypto: sahara - add support for i.MX53
  crypto: sahara - fix spinlock initialization
  crypto: arm - replace memset by memzero_explicit
  crypto: powerpc - replace memset by memzero_explicit
  crypto: sha - replace memset by memzero_explicit
  crypto: sparc - replace memset by memzero_explicit
  crypto: algif_skcipher - initialize upon init request
  crypto: algif_skcipher - removed unneeded code
  crypto: algif_skcipher - Fixed blocking recvmsg
  crypto: drbg - use memzero_explicit() for clearing sensitive data
  crypto: drbg - use MODULE_ALIAS_CRYPTO
  crypto: include crypto- module prefix in template
  crypto: user - add MODULE_ALIAS
  crypto: sha-mb - remove a bogus NULL check
  crytpo: qat - Fix 64 bytes requests
  ...

Merge second patchbomb from Andrew Morton:
 - the rest of MM
 - misc fs fixes
 - add execveat() syscall
 - new ratelimit feature for fault-injection
 - decompressor updates
 - ipc/ updates
 - fallocate feature creep
 - fsnotify cleanups
 - a few other misc things

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (99 commits)
  cgroups: Documentation: fix trivial typos and wrong paragraph numberings
  parisc: percpu: update comments referring to __get_cpu_var
  percpu: update local_ops.txt to reflect this_cpu operations
  percpu: remove __get_cpu_var and __raw_get_cpu_var macros
  fsnotify: remove destroy_list from fsnotify_mark
  fsnotify: unify inode and mount marks handling
  fallocate: create FAN_MODIFY and IN_MODIFY events
  mm/cma: make kmemleak ignore CMA regions
  slub: fix cpuset check in get_any_partial
  slab: fix cpuset check in fallback_alloc
  shmdt: use i_size_read() instead of ->i_size
  ipc/shm.c: fix overly aggressive shmdt() when calls span multiple segments
  ipc/msg: increase MSGMNI, remove scaling
  ipc/sem.c: increase SEMMSL, SEMMNI, SEMOPM
  ipc/sem.c: change memory barrier in sem_lock() to smp_rmb()
  lib/decompress.c: consistency of compress formats for kernel image
  decompress_bunzip2: off by one in get_next_block()
  usr/Kconfig: make initrd compression algorithm selection not expert
  fault-inject: add ratelimit option
  ratelimit: add initialization macro
  ...

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

__get_cpu_var was removed. Update comments to refer to
this_cpu_ptr() instead.
Signed-off-by: Christoph Lameter <cl@linux.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Update the documentation to reflect changes due to the availability of
this_cpu operations.
Signed-off-by: Christoph Lameter <cl@linux.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

No user is left in the kernel source tree.  Therefore we can drop the
definitions.

This is the final merge of the transition away from __get_cpu_var.  After
this patch the kernel will not build if anyone uses __get_cpu_var.
Signed-off-by: Christoph Lameter <cl@linux.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

destroy_list is used to track marks which still need waiting for srcu
period end before they can be freed.  However by the time mark is added to
destroy_list it isn't in group's list of marks anymore and thus we can
reuse fsnotify_mark->g_list for queueing into destroy_list.  This saves
two pointers for each fsnotify_mark.
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Eric Paris <eparis@redhat.com>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There's a lot of common code in inode and mount marks handling.  Factor it
out to a common helper function.
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Eric Paris <eparis@redhat.com>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The fanotify and the inotify API can be used to monitor changes of the
file system.  System call fallocate() modifies files.  Hence it should
trigger the corresponding fanotify (FAN_MODIFY) and inotify (IN_MODIFY)
events.  The most interesting case is FALLOC_FL_COLLAPSE_RANGE because
this value allows to create arbitrary file content from random data.

This patch adds the missing call to fsnotify_modify().

The FAN_MODIFY and IN_MODIFY event will be created when fallocate()
succeeds.  It will even be created if the file length remains unchanged,
e.g.  when calling fanotify with flag FALLOC_FL_KEEP_SIZE.

This logic was primarily chosen to keep the coding simple.

It resembles the logic of the write() system call.

When we call write() we always create a FAN_MODIFY event, even in the case
of overwriting with identical data.

Events FAN_MODIFY and IN_MODIFY do not provide any guarantee that data was
actually changed.

Furthermore even if if the filesize remains unchanged, fallocate() may
influence whether a subsequent write() will succeed and hence the
fallocate() call may be considered a modification.

The fallocate(2) man page teaches: After a successful call, subsequent
writes into the range specified by offset and len are guaranteed not to
fail because of lack of disk space.

So calling fallocate(fd, FALLOC_FL_KEEP_SIZE, offset, len) may result in
different outcomes of a subsequent write depending on the values of offset
and len.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@parisplace.org>
Cc: John McCutchan <john@johnmccutchan.com>
Cc: Robert Love <rlove@rlove.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>