Pull block core updates from Jens Axboe:
 "It's a big(ish) round this time, lots of development effort has gone
  into blk-mq in the last 3 months.  Generally we're heading to where
  3.16 will be a feature complete and performant blk-mq.  scsi-mq is
  progressing nicely and will hopefully be in 3.17.  A nvme port is in
  progress, and the Micron pci-e flash driver, mtip32xx, is converted
  and will be sent in with the driver pull request for 3.16.

  This pull request contains:

   - Lots of prep and support patches for scsi-mq have been integrated.
     All from Christoph.

   - API and code cleanups for blk-mq from Christoph.

   - Lots of good corner case and error handling cleanup fixes for
     blk-mq from Ming Lei.

   - A flew of blk-mq updates from me:

     * Provide strict mappings so that the driver can rely on the CPU
       to queue mapping.  This enables optimizations in the driver.

     * Provided a bitmap tagging instead of percpu_ida, which never
       really worked well for blk-mq.  percpu_ida relies on the fact
       that we have a lot more tags available than we really need, it
       fails miserably for cases where we exhaust (or are close to
       exhausting) the tag space.

     * Provide sane support for shared tag maps, as utilized by scsi-mq

     * Various fixes for IO timeouts.

     * API cleanups, and lots of perf tweaks and optimizations.

   - Remove 'buffer' from struct request.  This is ancient code, from
     when requests were always virtually mapped.  Kill it, to reclaim
     some space in struct request.  From me.

   - Remove 'magic' from blk_plug.  Since we store these on the stack
     and since we've never caught any actual bugs with this, lets just
     get rid of it.  From me.

   - Only call part_in_flight() once for IO completion, as includes two
     atomic reads.  Hopefully we'll get a better implementation soon, as
     the part IO stats are now one of the more expensive parts of doing
     IO on blk-mq.  From me.

   - File migration of block code from {mm,fs}/ to block/.  This
     includes bio.c, bio-integrity.c, bounce.c, and ioprio.c.  From me,
     from a discussion on lkml.

  That should describe the meat of the pull request.  Also has various
  little fixes and cleanups from Dave Jones, Shaohua Li, Duan Jiong,
  Fengguang Wu, Fabian Frederick, Randy Dunlap, Robert Elliott, and Sam
  Bradshaw"

* 'for-3.16/core' of git://git.kernel.dk/linux-block: (100 commits)
  blk-mq: push IPI or local end_io decision to __blk_mq_complete_request()
  blk-mq: remember to start timeout handler for direct queue
  block: ensure that the timer is always added
  blk-mq: blk_mq_unregister_hctx() can be static
  blk-mq: make the sysfs mq/ layout reflect current mappings
  blk-mq: blk_mq_tag_to_rq should handle flush request
  block: remove dead code in scsi_ioctl:blk_verify_command
  blk-mq: request initialization optimizations
  block: add queue flag for disabling SG merging
  block: remove 'magic' from struct blk_plug
  blk-mq: remove alloc_hctx and free_hctx methods
  blk-mq: add file comments and update copyright notices
  blk-mq: remove blk_mq_alloc_request_pinned
  blk-mq: do not use blk_mq_alloc_request_pinned in blk_mq_map_request
  blk-mq: remove blk_mq_wait_for_tags
  blk-mq: initialize request in __blk_mq_alloc_request
  blk-mq: merge blk_mq_alloc_reserved_request into blk_mq_alloc_request
  blk-mq: add helper to insert requests from irq context
  blk-mq: remove stale comment for blk_mq_complete_request()
  blk-mq: allow non-softirq completions
  ...

Pull MMC update from Ulf Hansson:
 "These patches are mainly updates for the mmci driver and have been
  tested in linux-next.

  Some ARM SoC related patches are also included and those have been
  acked from the corresponding maintainers to go through my mmc tree.

  Updates for mmci driver:
   - Put the device into low power state at system suspend.
   - Convert to the common mmc DT parser.
   - Add missing DT bindings needed for ux500.

  Updates for ARM ux500|u300:
   - Convert to the common mmc DT bindings.
   - Remove redundant board file for mmci platform data"

* tag 'mmc-v3.16-1' of git://git.linaro.org/people/ulf.hansson/mmc: (22 commits)
  mmc: mmci: Enforce DMA configuration through DT
  mmc: mmci: Enforce max frequency configuration through DT
  mmc: mmci: Enforce mmc capabilities through DT
  mmc: mmci: Enforce DT for signal direction and feedback clock
  ARM: ux500: Remove redundant board file for mmci platform data
  ARM: ux500: Add a vmmc regulator through DT for the poped eMMC for href
  ARM: ux500: Add the mmc capabilities flags to DT
  mmc: mmci: Enable MMC_CAP_CMD23
  mmc: mmci: Mark the DT bindings for highspeed mode as deprecated
  ARM: u300: Convert to the common mmc DT bindings for highspeed mode
  ARM: nomadik: Convert to the common mmc DT bindings for highspeed mode
  ARM: ux500: Convert to the common mmc DT bindings for highspeed mode
  ARM: ux500: Add mmci signal directions and feeback clock in DT for href
  mmc: mmci: Use the common mmc DT parser
  mmc: mmci: Add DT bindings for feedback clock pin
  mmc: mmci: Add DT bindings for signal direction
  mmc: mmci: Update DT documentation
  mmc: mmci: Convert to devm functions
  mmc: mmci: Convert to the mmc gpio API
  mmc: mmci: Put the device into low power state at system suspend
  ...

Pull HSI (High Speed Syncronous Interface) changes from Sebastian Reichel:
 "Please pull the following changes for the HSI subsystem, which I have
  taken over from Carlos Chinea <carlos.chinea@nokia.com>.

  The below patches have been worked on in the linux-omap mailinglist
  for 10 months and are well tested in linux-next (have been in there
  for more than two weeks) without any problems arising.  Apart from
  that potential regressions are very limited, because the subsystem is
  not yet used by any platform in the mainline kernel.

   - Add some documentation for the HSI subsystem

   - Add Device Tree support for the HSI subsystem

   - Add OMAP3 SSI driver (SSI is a legacy variant of HSI)

   - Add Nokia N900 Modem driver (without speech support for now)"

* tag 'hsi-for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-hsi:
  HSI: Introduce Nokia N900 modem driver
  HSI: Introduce driver for SSI Protocol
  Documentation: DT: omap-ssi binding documentation
  HSI: Introduce OMAP SSI driver
  HSI: Add common DT binding for HSI client devices
  HSI: export method to (un)register clients
  HSI: Add channel resource support to HSI clients
  HSI: method to unregister clients from an hsi port
  HSI: hsi-char: fix driver for multiport scenarios
  MAINTAINERS: update HSI entry
  Documentation: HSI: Add some general description for the HSI subsystem

Pull EDAC changes from Borislav Petkov:
 "Just two small fixlets.

  We have more in the pipe but we didn't get ready in time so more stuff
  next time"

* tag 'edac_for_3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp:
  EDAC: Fix MC scrub mode comparsion bug for correctable errors
  EDAC, MCE, AMD: Remove leftover unused mask

Merge tag 'gpio-v3.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio into next

Pull GPIO updates from Linus Walleij:
 "This is the bulk of GPIO changes for the v3.16 series.

  There is a lot of action in the GPIO subsystem doing refactorings and
  cleanups, almost as many deletions as insertions and minor feature
  growth and no new drivers this time.  Which is actually pretty nice.
  Some GPIO-related stuff will come in through the pin control tree as
  well.

  Details:

   - We are finalizing and fixing up the gpiochip irqchip helpers
     bringing a helpful irqchip implementation into the gpiolib core and
     avoiding duplicate code and, more importantly, duplicate bug fixes:

     * Support for using the helpers with threaded interrupt handlers as
       used on sleeping GPIO-irqchips

     * Do not set up hardware triggers for edges or levels if the
       default IRQ type is IRQ_TYPE_NONE - some drivers would exploit
       the fact that you could get default initialization of the IRQ
       type from the core at probe() but if no default type is set up
       from the helper, we should not call the driver to configure
       anything.  Wait until a consumer requests the interrupt instead.

     * Make the irqchip helpers put the GPIO irqs into their own lock
       class.  The GPIO irqchips can often emit (harmless, but annoying)
       lockdep warnings about recursions when they are in fact just
       cascaded IRQs.  By putting them into their own lock class we help
       the lockdep core to keep track of things.

     * Switch the tc3589x GPIO expanders to use the irqchip helpers

     * Switch the OMAP GPIO driver to use the irqchip helpers

     * Add some documentation for the irqchip helpers

     * select IRQ_DOMAIN when using the helpers since some platforms may
       not be using this by default and it's a strict dependency.

   - Continued GPIO descriptor refactoring:

     * Remove the one instance of gpio_to_desc() from the device tree
       code, making the OF GPIO code use GPIO descriptors only.

     * Introduce gpiod_get_optional() and gpiod_get_optional_index()
       akin to the similar regulator functions for cases where the use
       of GPIO is optional and not strictly required.

     * Make of_get_named_gpiod_flags() private - we do not want to
       unnecessarily expose APIs to drivers that make the gpiolib harder
       than necessary to maintain and refactor.  Privatize this
       function.

   - Support "-gpio" suffix for the OF GPIO retrieveal path.  We used to
     look for "foo-gpios" or just "gpios" in device tree nodes, but it
     turns out that some drivers with a single GPIO line will just state
     "foo-gpio" (singularis).  Sigh.  Support this with a fallback
     looking for it, as this simplifies driver code and handles it in
     core code.

   - Switch the ACPI GPIO core to fetch GPIOs with the *_cansleep
     function variants as the GPIO operation region handler can sleep,
     and shall be able to handle gpiochips that sleep.

   - Tons of cleanups and janitorial work from Jingoo Han, Axel Lin,
     Javier Martinez Canillas and Abdoulaye Berthe.  Notably Jingoo cut
     off a ton of pointless OOM messages.

   - Incremental development and fixes for various drivers, nothing
     really special here"

* tag 'gpio-v3.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (85 commits)
  gpio: select IRQ_DOMAIN for gpiolib irqchip helpers
  gpio: pca953x: use gpiolib irqchip helpers
  gpio: pcf857x: Add IRQF_SHARED when request irq
  gpio: pcf857x: Avoid calling irq_domain_cleanup twice
  gpio: mcp23s08: switch chip count to int
  gpio: dwapb: use a second irq chip
  gpio: ep93xx: Use devm_ioremap_resource()
  gpio: mcp23s08: fixed count variable for devicetree probing
  gpio: Add run-time dependencies to R-Car driver
  gpio: pch: add slab include
  Documentation / ACPI: Fix location of GPIO documentation
  gpio / ACPI: use *_cansleep version of gpiod_get/set APIs
  gpio: generic: add request function pointer
  gpio-pch: Fix Kconfig dependencies
  gpio: make of_get_named_gpiod_flags() private
  gpio: gpioep93xx: use devm functions
  gpio: janzttl: use devm function
  gpio: timberdale: use devm functions
  gpio: bt8xx: use devm function for memory allocation
  gpio: include linux/bug.h in interface header
  ...

Merge tag 'stable/for-linus-3.16-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip into next

Pull Xen updates from David Vrabel:
 "xen: features and fixes for 3.16-rc0
   - support foreign mappings in PVH domains (needed when dom0 is PVH)

   - fix mapping high MMIO regions in x86 PV guests (this is also the
     first half of removing the PAGE_IOMAP PTE flag).

   - ARM suspend/resume support.

   - ARM multicall support"

* tag 'stable/for-linus-3.16-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  x86/xen: map foreign pfns for autotranslated guests
  xen-acpi-processor: Don't display errors when we get -ENOSYS
  xen/pciback: Document the entry points for 'pcistub_put_pci_dev'
  xen/pciback: Document when the 'unbind' and 'bind' functions are called.
  xen-pciback: Document when we FLR an PCI device.
  xen-pciback: First reset, then free.
  xen-pciback: Cleanup up pcistub_put_pci_dev
  x86/xen: do not use _PAGE_IOMAP in xen_remap_domain_mfn_range()
  x86/xen: set regions above the end of RAM as 1:1
  x86/xen: only warn once if bad MFNs are found during setup
  x86/xen: compactly store large identity ranges in the p2m
  x86/xen: fix set_phys_range_identity() if pfn_e > MAX_P2M_PFN
  x86/xen: rename early_p2m_alloc() and early_p2m_alloc_middle()
  xen/x86: set panic notifier priority to minimum
  arm,arm64/xen: introduce HYPERVISOR_suspend()
  xen: refactor suspend pre/post hooks
  arm: xen: export HYPERVISOR_multicall to modules.
  arm64: introduce virt_to_pfn
  arm/xen: Remove definiition of virt_to_pfn in asm/xen/page.h
  arm: xen: implement multicall hypercall support.

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k into next

Pull m68k updates from Geert Uytterhoeven:
 "Highlights:
   - support for running kernels in fast TT-RAM instead of slow ST-RAM
     on Atari
   - multi-platform EARLY_PRINTK
   - better support for machines with lots of RAM (think ARAnyM), and
     for running kernels larger than 4 MiB (think multi-platform)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
  m68k/hp300: Convert printk to pr_foo()
  m68k/apollo: Convert printk to pr_foo()
  m68k/amiga: Convert printk(foo to pr_foo()
  m68k: Increase initial mapping to 8 or 16 MiB if possible
  m68k: Update defconfigs for v3.15-rc2
  m68k/atari: fix SCC initialization for debug console
  m68k/mvme16x: Adopt common boot console
  m68k: Multi-platform EARLY_PRINTK
  m68k: Toward platform agnostic framebuffer debug logging
  m68k/atari - atari_scsi: use correct virt/phys translation for DMA buffer
  m68k/atari - ataflop: use correct virt/phys translation for DMA buffer
  m68k/atari - atafb: convert allocation of fb ram to new interface
  m68k/atari - stram: alloc ST-RAM pool even if kernel not in ST-RAM

Remove the option to provide DMA configuration as platform data,
enforce it through DT.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Roland Stigge <stigge@antcom.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>

Pull powerpc fix from Ben Herrenschmidt:
 "Here's just one trivial patch to wire up sys_renameat2 which I seem to
  have completely missed so far.

  (My test build scripts fwd me warnings but miss the ones generated for
  missing syscalls)"

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc: Wire renameat2() syscall

Pull MIPS fixes from Ralf Baechle:
 "A fair number of fixes across the field.  Nothing terribly
  complicated; the one liners in below changelog should be fairly
  descriptive.

  Noteworthy is the SB1 change which the result of changes to binutils
  resulting in one big gas warning for most files being assembled as
  well as the asid_cache and branch emulation fixes which fix corruption
  or possible uninteded behaviour of kernel or application code.  The
  remainder of fixes are more platforms or subsystem specific"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: R46000: Fix Micro-assembler field overflow for R4600 V2
  MIPS: ptrace: Avoid smp_processor_id() in preemptible code
  MIPS: Lemote 2F: cs5536: mfgpt: use raw locks
  MIPS: SB1: Fix excessive kernel warnings.
  MIPS: RC32434: fix broken PCI resource initialization
  MIPS: malta: memory.c: Initialize the 'memsize' variable
  MIPS: Fix typo when reporting cache and ftlb errors for ImgTec cores
  MIPS: Fix inconsistancy of __NR_Linux_syscalls value
  MIPS: Fix branch emulation of branch likely instructions.
  MIPS: Fix a typo error in AUDIT_ARCH definition
  MIPS: Change type of asid_cache to unsigned long

Pull scheduler fixes from Ingo Molnar:
 "Various fixlets, mostly related to the (root-only) SCHED_DEADLINE
  policy, but also a hotplug bug fix and a fix for a NR_CPUS related
  overallocation bug causing a suspend/resume regression"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Fix hotplug vs. set_cpus_allowed_ptr()
  sched/cpupri: Replace NR_CPUS arrays
  sched/deadline: Replace NR_CPUS arrays
  sched/deadline: Restrict user params max value to 2^63 ns
  sched/deadline: Change sched_getparam() behaviour vs SCHED_DEADLINE
  sched: Disallow sched_attr::sched_policy < 0
  sched: Make sched_setattr() correctly return -EFBIG

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Pull core futex/rtmutex fixes from Thomas Gleixner:
 "Three fixlets for long standing issues in the futex/rtmutex code
  unearthed by Dave Jones syscall fuzzer:

   - Add missing early deadlock detection checks in the futex code
   - Prevent user space from attaching a futex to kernel threads
   - Make the deadlock detector of rtmutex work again

  Looks large, but is more comments than code change"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rtmutex: Fix deadlock detector for real
  futex: Prevent attaching to kernel threads
  futex: Add another early deadlock detection check

Pull drm fixes from Dave Airlie:
 "Mostly quiet now:

  i915:
    fixing userspace visiblie issues, all stable marked

  radeon:
    one more pll fix, two crashers, one suspend/resume regression"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/radeon: Resume fbcon last
  drm/radeon: only allocate necessary size for vm bo list
  drm/radeon: don't allow RADEON_GEM_DOMAIN_CPU for command submission
  drm/radeon: avoid crash if VM command submission isn't available
  drm/radeon: lower the ref * post PLL maximum once more
  drm/i915: Prevent negative relocation deltas from wrapping
  drm/i915: Only copy back the modified fields to userspace from execbuffer
  drm/i915: Fix dynamic allocation of physical handles

lock_parent() very much on purpose does nested locking of dentries, and
is careful to maintain the right order (lock parent first).  But because
it didn't annotate the nested locking order, lockdep thought it might be
a deadlock on d_lock, and complained.

Add the proper annotation for the inner locking of the child dentry to
make lockdep happy.

Introduced by commit 046b961b ("shrink_dentry_list(): take parent's
->d_lock earlier").
Reported-and-tested-by: Josh Boyer <jwboyer@fedoraproject.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We have callers outside of the blk-mq proper (like timeouts) that
want to call __blk_mq_complete_request(), so rename the function
and put the decision code for whether to use ->softirq_done_fn
or blk_mq_endio() into __blk_mq_complete_request().

This also makes the interface more logical again.
blk_mq_complete_request() attempts to atomically mark the request
completed, and calls __blk_mq_complete_request() if successful.
__blk_mq_complete_request() then just ends the request.
Signed-off-by: Jens Axboe <axboe@fb.com>

So a few people complained that

commit 177cf92d
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Tue Apr 1 22:14:59 2014 +0200

    drm/crtc-helpers: fix dpms on logic

which was merged into 3.15-rc1, broke resume on radeons. Strangely git
bisect lead everyone to

commit 25f397a4
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Fri Jul 19 18:57:11 2013 +0200

    drm/crtc-helper: explicit DPMS on after modeset

which was merged long ago and actually part of 3.14.

Digging deeper I've noticed (again) that the call to
drm_helper_resume_force_mode in the radeon resume handlers was a no-op
previously because everything gets shut down on suspend. radeon does
this with explicit calls to drm_helper_connector_dpms with DPMS_OFF.
But with 177c we now force the dpms state to ON, so suddenly
resume_force_mode actually forced the crtcs back on.

This is the intention of the change after all, the problem is that
radeon resumes the fbdev console layer _before_ restoring the display,
through calling fb_set_suspend. And fbcon does an immediate ->set_par,
which in turn causes the same forced mode restore to happen.

Two concurrent modeset operations didn't lead to happiness. Fix this
by delaying the fbcon resume until the end of the readeon resum
functions.

v2: Fix up a bit of the spelling fail.

References: https://lkml.org/lkml/2014/5/29/1043
References: https://lkml.org/lkml/2014/5/2/388
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=74751Tested-by: Ken Moffat <zarniwhoop@ntlworld.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Ken Moffat <zarniwhoop@ntlworld.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@gmail.com>

this is the next pull request for stashed up radeon fixes for 3.15. This is finally calming down with only four patches in this pull request.

* 'drm-fixes-3.15' of git://people.freedesktop.org/~deathsimple/linux:
  drm/radeon: only allocate necessary size for vm bo list
  drm/radeon: don't allow RADEON_GEM_DOMAIN_CPU for command submission
  drm/radeon: avoid crash if VM command submission isn't available
  drm/radeon: lower the ref * post PLL maximum once more

Commit 07068d5b added a direct-to-hw-queue mode, but this mode
needs to remember to add the request timeout handler as well.
Without it, we don't track timeouts for these requests.
Signed-off-by: Jens Axboe <axboe@fb.com>

Commit f793aa53 relaxed the timer addition a little too much.
If the timer isn't pending, we always need to add it.
Signed-off-by: Jens Axboe <axboe@fb.com>

Pull input subsystem fixes from Dmitry Torokhov:
 "A couple of driver/build fixups and also redone quirk for Synaptics
  touchpads on Lenovo boxes (now using PNP IDs instead of DMI data to
  limit number of quirks)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: synaptics - change min/max quirk table to pnp-id matching
  Input: synaptics - add a matches_pnp_id helper function
  Input: synaptics - T540p - unify with other LEN0034 models
  Input: synaptics - add min/max quirk for the ThinkPad W540
  Input: ambakmi - request a shared interrupt for AMBA KMI devices
  Input: pxa27x-keypad - fix generating scancode
  Input: atmel-wm97xx - only build for AVR32
  Input: fix ps2/serio module dependency

Pull firewire fix from Stefan Richter:
 "A regression fix for the IEEE 1394 subsystem: re-enable IRQ-based
  asynchronous request reception at addresses below 128 TB"

* tag 'firewire-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394:
  firewire: revert to 4 GB RDMA, fix protocols using Memory Space

Pull device-mapper fixes from Mike Snitzer:
 "A dm-cache stable fix to split discards on cache block boundaries
  because dm-cache cannot yet handle discards that span cache blocks.

  Really fix a dm-mpath LOCKDEP warning that was introduced in -rc1.

  Add a 'no_space_timeout' control to dm-thinp to restore the ability to
  queue IO indefinitely when no data space is available.  This fixes a
  change in behavior that was introduced in -rc6 where the timeout
  couldn't be disabled"

* tag 'dm-3.15-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm mpath: really fix lockdep warning
  dm cache: always split discards on cache block boundaries
  dm thin: add 'no_space_timeout' dm-thin-pool module param

While I play inhouse patches with much memory pressure on qemu-kvm,
3.14 kernel was randomly crashed. The reason was kernel stack overflow.

When I investigated the problem, the callstack was a little bit deeper
by involve with reclaim functions but not direct reclaim path.

I tried to diet stack size of some functions related with alloc/reclaim
so did a hundred of byte but overflow was't disappeard so that I encounter
overflow by another deeper callstack on reclaim/allocator path.

Of course, we might sweep every sites we have found for reducing
stack usage but I'm not sure how long it saves the world(surely,
lots of developer start to add nice features which will use stack
agains) and if we consider another more complex feature in I/O layer
and/or reclaim path, it might be better to increase stack size(
meanwhile, stack usage on 64bit machine was doubled compared to 32bit
while it have sticked to 8K. Hmm, it's not a fair to me and arm64
already expaned to 16K. )

So, my stupid idea is just let's expand stack size and keep an eye
toward stack consumption on each kernel functions via stacktrace of ftrace.
For example, we can have a bar like that each funcion shouldn't exceed 200K
and emit the warning when some function consumes more in runtime.
Of course, it could make false positive but at least, it could make a
chance to think over it.

I guess this topic was discussed several time so there might be
strong reason not to increase kernel stack size on x86_64, for me not
knowing so Ccing x86_64 maintainers, other MM guys and virtio
maintainers.

Here's an example call trace using up the kernel stack:

         Depth    Size   Location    (51 entries)
         -----    ----   --------
   0)     7696      16   lookup_address
   1)     7680      16   _lookup_address_cpa.isra.3
   2)     7664      24   __change_page_attr_set_clr
   3)     7640     392   kernel_map_pages
   4)     7248     256   get_page_from_freelist
   5)     6992     352   __alloc_pages_nodemask
   6)     6640       8   alloc_pages_current
   7)     6632     168   new_slab
   8)     6464       8   __slab_alloc
   9)     6456      80   __kmalloc
  10)     6376     376   vring_add_indirect
  11)     6000     144   virtqueue_add_sgs
  12)     5856     288   __virtblk_add_req
  13)     5568      96   virtio_queue_rq
  14)     5472     128   __blk_mq_run_hw_queue
  15)     5344      16   blk_mq_run_hw_queue
  16)     5328      96   blk_mq_insert_requests
  17)     5232     112   blk_mq_flush_plug_list
  18)     5120     112   blk_flush_plug_list
  19)     5008      64   io_schedule_timeout
  20)     4944     128   mempool_alloc
  21)     4816      96   bio_alloc_bioset
  22)     4720      48   get_swap_bio
  23)     4672     160   __swap_writepage
  24)     4512      32   swap_writepage
  25)     4480     320   shrink_page_list
  26)     4160     208   shrink_inactive_list
  27)     3952     304   shrink_lruvec
  28)     3648      80   shrink_zone
  29)     3568     128   do_try_to_free_pages
  30)     3440     208   try_to_free_pages
  31)     3232     352   __alloc_pages_nodemask
  32)     2880       8   alloc_pages_current
  33)     2872     200   __page_cache_alloc
  34)     2672      80   find_or_create_page
  35)     2592      80   ext4_mb_load_buddy
  36)     2512     176   ext4_mb_regular_allocator
  37)     2336     128   ext4_mb_new_blocks
  38)     2208     256   ext4_ext_map_blocks
  39)     1952     160   ext4_map_blocks
  40)     1792     384   ext4_writepages
  41)     1408      16   do_writepages
  42)     1392      96   __writeback_single_inode
  43)     1296     176   writeback_sb_inodes
  44)     1120      80   __writeback_inodes_wb
  45)     1040     160   wb_writeback
  46)      880     208   bdi_writeback_workfn
  47)      672     144   process_one_work
  48)      528     112   worker_thread
  49)      416     240   kthread
  50)      176     176   ret_from_fork

[ Note: the problem is exacerbated by certain gcc versions that seem to
  generate much bigger stack frames due to apparently bad coalescing of
  temporaries and generating too many spills.  Rusty saw gcc-4.6.4 using
  35% more stack on the virtio path than 4.8.2 does, for example.

  Minchan not only uses such a bad gcc version (4.6.3 in his case), but
  some of the stack use is due to debugging (CONFIG_DEBUG_PAGEALLOC is
  what causes that kernel_map_pages() frame, for example). But we're
  clearly getting too close.

  The VM code also seems to have excessive stack frames partly for the
  same compiler reason, triggered by excessive inlining and lots of
  function arguments.

  We need to improve on our stack use, but in the meantime let's do this
  simple stack increase too.  Unlike most earlier reports, there is
  nothing simple that stands out as being really horribly wrong here,
  apart from the fact that the stack frames are just bigger than they
  should need to be.        - Linus ]
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michael S Tsirkin <mst@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: PJ Waskiewicz <pjwaskiewicz@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull vfs dcache livelock fix from Al Viro:
 "Fixes for livelocks in shrink_dentry_list() introduced by fixes to
  shrink list corruption; the root cause was that trylock of parent's
  ->d_lock could be disrupted by d_walk() happening on other CPUs,
  resulting in shrink_dentry_list() making no progress *and* the same
  d_walk() being called again and again for as long as
  shrink_dentry_list() doesn't get past that mess.

  The solution is to have shrink_dentry_list() treat that trylock
  failure not as 'try to do the same thing again', but 'lock them in the
  right order'"

* 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  dentry_kill() doesn't need the second argument now
  dealing with the rest of shrink_dentry_list() livelock
  shrink_dentry_list(): take parent's ->d_lock earlier
  expand dentry_kill(dentry, 0) in shrink_dentry_list()
  split dentry_kill()
  lift the "already marked killed" case into shrink_dentry_list()

CC: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

it's 1 in the only remaining caller.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

We have the same problem with ->d_lock order in the inner loop, where
we are dropping references to ancestors.  Same solution, basically -
instead of using dentry_kill() we use lock_parent() (introduced in the
previous commit) to get that lock in a safe way, recheck ->d_count
(in case if lock_parent() has ended up dropping and retaking ->d_lock
and somebody managed to grab a reference during that window), trylock
the inode->i_lock and use __dentry_kill() to do the rest.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

The cause of livelocks there is that we are taking ->d_lock on
dentry and its parent in the wrong order, forcing us to use
trylock on the parent's one.  d_walk() takes them in the right
order, and unfortunately it's not hard to create a situation
when shrink_dentry_list() can't make progress since trylock
keeps failing, and shrink_dcache_parent() or check_submounts_and_drop()
keeps calling d_walk() disrupting the very shrink_dentry_list() it's
waiting for.

Solution is straightforward - if that trylock fails, let's unlock
the dentry itself and take locks in the right order.  We need to
stabilize ->d_parent without holding ->d_lock, but that's doable
using RCU.  And we'd better do that in the very beginning of the
loop in shrink_dentry_list(), since the checks on refcount, etc.
would need to be redone anyway.

That deals with a half of the problem - killing dentries on the
shrink list itself.  Another one (dropping their parents) is
in the next commit.

locking parent is interesting - it would be easy to do rcu_read_lock(),
lock whatever we think is a parent, lock dentry itself and check
if the parent is still the right one.  Except that we need to check
that *before* locking the dentry, or we are risking taking ->d_lock
out of order.  Fortunately, once the D1 is locked, we can check if
D2->d_parent is equal to D1 without the need to lock D2; D2->d_parent
can start or stop pointing to D1 only under D1->d_lock, so taking
D1->d_lock is enough.  In other words, the right solution is
rcu_read_lock/lock what looks like parent right now/check if it's
still our parent/rcu_read_unlock/lock the child.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Currently blk-mq registers all the hardware queues in sysfs,
regardless of whether it uses them (e.g. they have CPU mappings)
or not. The unused hardware queues lack the cpux/ directories,
and the other sysfs entries (like active, pending, etc) are all
zeroes.

Change this so that sysfs correctly reflects the current mappings
of the hardware queues.
Signed-off-by: Jens Axboe <axboe@fb.com>

flush request is special, which borrows the tag from the parent
request. Hence blk_mq_tag_to_rq needs special handling to return
the flush request from the tag.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

No need to always allocate the theoretical maximum here.
Signed-off-by: Christian König <christian.koenig@amd.com>

It hangs the hardware.
Signed-off-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Cc: stable@vger.kernel.org

Signed-off-by: Christian König <christian.koenig@amd.com>
CC: stable@vger.kernel.org

Let's be conservative and use 100 here until we find something better.

Bugs: https://bugzilla.kernel.org/show_bug.cgi?id=75241Signed-off-by: Christian König <christian.koenig@amd.com>

Pull ARM fixes from Russell King:
 "The usual random collection of relatively small ARM fixes"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8063/1: bL_switcher: fix individual online status reporting of removed CPUs
  ARM: 8064/1: fix v7-M signal return
  ARM: 8057/1: amba: Add Qualcomm vendor ID.
  ARM: 8052/1: unwind: Fix handling of "Pop r4-r[4+nnn],r14" opcode
  ARM: 8051/1: put_user: fix possible data corruption in put_user
  ARM: 8048/1: fix v7-M setup stack location

Pull arm64 fix from Will Deacon:
 "Fix CoW regression for transparent hugepages by routing set_pmd_at to
  set_pte_at, which correctly handles PTE_WRITE and will mark the
  resulting table entry as read-only where appropriate"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: mm: fix pmd_write CoW brokenness

Pull ACPI and power management fixes from Rafael Wysocki:
 "These are three stable-candidate fixes, one for the ACPI thermal
  driver and two for cpufreq drivers.

  Specifics:

   - A workqueue is destroyed too early during the ACPI thermal driver
     module unload which leads to a NULL pointer dereference in the
     driver's remove callback.  Fix from Aaron Lu.

   - A wrong argument is passed to devm_regulator_get_optional() in the
     probe routine of the cpu0 cpufreq driver which leads to resource
     leaks if the driver is unbound from the cpufreq platform device.
     Fix from Lucas Stach.

   - A lock is missing in cpufreq_governor_dbs() which leads to memory
     corruption and NULL pointer dereferences during system
     suspend/resume, for example.  Fix from Bibek Basu"

* tag 'pm+acpi-3.15-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / thermal: fix workqueue destroy order
  cpufreq: cpu0: drop wrong devm usage
  cpufreq: remove race while accessing cur_policy

Pull clock fixes from Mike Turquette:
 "Small number of user-visible regression fixes for clock drivers.

  There is a memory leak fix for an ST platform, an infinite Loop Of
  Doom fix for the recent changes to the basic clock divider (hopefully
  the last fix for those recent changes) and some Tegra PLL changes
  which keep PCI from being hosed on that platform"

* tag 'clk-fixes-for-linus' of git://git.linaro.org/people/mike.turquette/linux:
  clk: st: Fix memory leak
  clk: divider: Fix table round up function
  clk: tegra: Fix enabling of PLLE
  clk: tegra: Introduce divider mask and shift helpers
  clk: tegra: Fix PLLE programming