Rename various methods to have either a "dm_old" or "dm_mq" prefix.
Improve code comments to assist with understanding the duality of code
that handles both "dm_old" and "dm_mq" cases.

It is no much easier to quickly look at the code and _know_ that a given
method is either 1) "dm_old" only 2) "dm_mq" only 3) common to both.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Remove all fiddley code that propped up this support for a blk-mq
request-queue ontop of all .request_fn devices.

Testing has proven this niche request-based dm-mq mode to be buggy, when
testing fault tolerance with DM multipath, and there is no point trying
to preserve it.

Should help improve efficiency of pure dm-mq code and make code
maintenance less delicate.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

old_stop_queue() was checking blk_queue_stopped() without holding the
q->queue_lock.

dm_requeue_original_request() needed to check blk_queue_stopped(), with
q->queue_lock held, before calling blk_mq_kick_requeue_list().  And a
side-effect of that change is start_queue() must also call
blk_mq_kick_requeue_list().
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

The blk_mq_tag_set is only needed for dm-mq support.  There is point
wasting space in 'struct mapped_device' for non-dm-mq devices.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> # check kzalloc return

Allow user to change these values via module params or sysfs.

'dm_mq_nr_hw_queues' defaults to 1 (max 32).

'dm_mq_queue_depth' defaults to 2048 (up from 64, which proved far too
small under moderate sized workloads -- the dm-multipath device would
continuously block waiting for tags (requests) to become available).
The maximum is BLK_MQ_MAX_DEPTH (currently 10240).

Keep in mind the total number of pre-allocated requests per
request-based dm-mq device is 'dm_mq_nr_hw_queues' * 'dm_mq_queue_depth'
(currently 2048).
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

DM multipath is the only request-based DM target -- which only supports
tables with a single target that is immutable.  Leverage this fact in
dm_request_fn().
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

DM multipath is the only dm-mq target.  But that aside, request-based DM
only supports tables with a single target that is immutable.  Leverage
this fact in dm_mq_queue_rq() by using the 'immutable_target' stored in
the mapped_device when the table was made active.  This saves the need
to even take the read-side of the SRCU via dm_{get,put}_live_table.

If the active DM table does not have an immutable target (e.g. "error"
target was swapped in) then fallback to the slow-path where the target
is looked up from the live table.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

The DM_TARGET_WILDCARD feature indicates that the "error" target may
replace any target; even immutable targets.  This feature will be useful
to preserve the ability to replace the "multipath" target even once it
is formally converted over to having the DM_TARGET_IMMUTABLE feature.

Also, implicit in the DM_TARGET_WILDCARD feature flag being set is that
.map, .map_rq, .clone_and_map_rq and .release_clone_rq are all defined
in the target_type.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

The request-based DM support for checking queue congestion doesn't
require access to the live DM table.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Request-based DM's blk-mq support (dm-mq) was reported to be 50% slower
than if an underlying null_blk device were used directly.  One of the
reasons for this drop in performance is that blk_insert_clone_request()
was calling blk_mq_insert_request() with @async=true.  This forced the
use of kblockd_schedule_delayed_work_on() to run the blk-mq hw queues
which ushered in ping-ponging between process context (fio in this case)
and kblockd's kworker to submit the cloned request.  The ftrace
function_graph tracer showed:

  kworker-2013  =>   fio-12190
  fio-12190    =>  kworker-2013
  ...
  kworker-2013  =>   fio-12190
  fio-12190    =>  kworker-2013
  ...

Fixing blk_insert_clone_request()'s blk_mq_insert_request() call to
_not_ use kblockd to submit the cloned requests isn't enough to
eliminate the observed context switches.

In addition to this dm-mq specific blk-core fix, there are 2 DM core
fixes to dm-mq that (when paired with the blk-core fix) completely
eliminate the observed context switching:

1)  don't blk_mq_run_hw_queues in blk-mq request completion

    Motivated by desire to reduce overhead of dm-mq, punting to kblockd
    just increases context switches.

    In my testing against a really fast null_blk device there was no benefit
    to running blk_mq_run_hw_queues() on completion (and no other blk-mq
    driver does this).  So hopefully this change doesn't induce the need for
    yet another revert like commit 621739b0 !

2)  use blk_mq_complete_request() in dm_complete_request()

    blk_complete_request() doesn't offer the traditional q->mq_ops vs
    .request_fn branching pattern that other historic block interfaces
    do (e.g. blk_get_request).  Using blk_mq_complete_request() for
    blk-mq requests is important for performance.  It should be noted
    that, like blk_complete_request(), blk_mq_complete_request() doesn't
    natively handle partial completions -- but the request-based
    DM-multipath target does provide the required partial completion
    support by dm.c:end_clone_bio() triggering requeueing of the request
    via dm-mpath.c:multipath_end_io()'s return of DM_ENDIO_REQUEUE.

dm-mq fix #2 is _much_ more important than #1 for eliminating the
context switches.
Before: cpu          : usr=15.10%, sys=59.39%, ctx=7905181, majf=0, minf=475
After:  cpu          : usr=20.60%, sys=79.35%, ctx=2008, majf=0, minf=472

With these changes multithreaded async read IOPs improved from ~950K
to ~1350K for this dm-mq stacked on null_blk test-case.  The raw read
IOPs of the underlying null_blk device for the same workload is ~1950K.

Fixes: 7fb4898e ("block: add blk-mq support to blk_insert_cloned_request()")
Fixes: bfebd1cd ("dm: add full blk-mq support to request-based DM")
Cc: stable@vger.kernel.org # 4.1+
Reported-by: NSagi Grimberg <sagig@dev.mellanox.co.il>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Acked-by: NJens Axboe <axboe@kernel.dk>

Rename dm_get_live_table_for_ioctl to dm_grab_bdev_for_ioctl and have it
do the dm_{get,put}_live_table() rather than split those operations.

The dm_grab_bdev_for_ioctl() callers only care about the block_device
associated with a singleton DM device so there isn't any need to retain
a reference to the live DM table.  It is sufficient to:
1) dm_get_live_table()
2) bdgrab() the bdev associated with the singleton table's target
3) dm_put_live_table()
4) bdput() the bdev
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

None of the callers actually used the returned target.
Also, just reuse bdev pointer passed to dm_blk_ioctl().
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Using request-based DM mpath configured with the following stacking
(.request_fn DM mpath ontop of scsi-mq paths):

echo Y > /sys/module/scsi_mod/parameters/use_blk_mq
echo N > /sys/module/dm_mod/parameters/use_blk_mq

'struct dm_rq_target_io' would leak if a request is requeued before a
blk-mq clone is allocated (or fails to allocate).  free_rq_tio()
wasn't being called.

kmemleak reported:

unreferenced object 0xffff8800b90b98c0 (size 112):
  comm "kworker/7:1H", pid 5692, jiffies 4295056109 (age 78.589s)
  hex dump (first 32 bytes):
    00 d0 5c 2c 03 88 ff ff 40 00 bf 01 00 c9 ff ff  ..\,....@.......
    e0 d9 b1 34 00 88 ff ff 00 00 00 00 00 00 00 00  ...4............
  backtrace:
    [<ffffffff81672b6e>] kmemleak_alloc+0x4e/0xb0
    [<ffffffff811dbb63>] kmem_cache_alloc+0xc3/0x1e0
    [<ffffffff8117eae5>] mempool_alloc_slab+0x15/0x20
    [<ffffffff8117ec1e>] mempool_alloc+0x6e/0x170
    [<ffffffffa00029ac>] dm_old_prep_fn+0x3c/0x180 [dm_mod]
    [<ffffffff812fbd78>] blk_peek_request+0x168/0x290
    [<ffffffffa0003e62>] dm_request_fn+0xb2/0x1b0 [dm_mod]
    [<ffffffff812f66e3>] __blk_run_queue+0x33/0x40
    [<ffffffff812f9585>] blk_delay_work+0x25/0x40
    [<ffffffff81096fff>] process_one_work+0x14f/0x3d0
    [<ffffffff81097715>] worker_thread+0x125/0x4b0
    [<ffffffff8109ce88>] kthread+0xd8/0xf0
    [<ffffffff8167cb8f>] ret_from_fork+0x3f/0x70
    [<ffffffffffffffff>] 0xffffffffffffffff

crash> struct -o dm_rq_target_io
struct dm_rq_target_io {
    ...
}
SIZE: 112

Fixes: e5863d9a ("dm: allocate requests in target when stacking on blk-mq devices")
Cc: stable@vger.kernel.org # 4.0+
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

Pull x86 fixes from Ingo Molnar:
 "This is unusually large, partly due to the EFI fixes that prevent
  accidental deletion of EFI variables through efivarfs that may brick
  machines.  These fixes are somewhat involved to maintain compatibility
  with existing install methods and other usage modes, while trying to
  turn off the 'rm -rf' bricking vector.

  Other fixes are for large page ioremap()s and for non-temporal
  user-memcpy()s"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Fix vmalloc_fault() to handle large pages properly
  hpet: Drop stale URLs
  x86/uaccess/64: Handle the caching of 4-byte nocache copies properly in __copy_user_nocache()
  x86/uaccess/64: Make the __copy_user_nocache() assembly code more readable
  lib/ucs2_string: Correct ucs2 -> utf8 conversion
  efi: Add pstore variables to the deletion whitelist
  efi: Make efivarfs entries immutable by default
  efi: Make our variable validation list include the guid
  efi: Do variable name validation tests in utf8
  efi: Use ucs2_as_utf8 in efivarfs instead of open coding a bad version
  lib/ucs2_string: Add ucs2 -> utf8 helper functions

Pull perf fixes from Ingo Molnar:
 "A handful of CPU hotplug related fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Plug potential memory leak in CPU_UP_PREPARE
  perf/core: Remove the bogus and dangerous CPU_DOWN_FAILED hotplug state
  perf/core: Remove bogus UP_CANCELED hotplug state
  perf/x86/amd/uncore: Plug reference leak

Pull powerpc fixes from Michael Ellerman:
 - Fix build error on 32-bit with checkpoint restart from Aneesh Kumar
 - Fix dedotify for binutils >= 2.26 from Andreas Schwab
 - Don't trace hcalls on offline CPUs from Denis Kirjanov
 - eeh: Fix stale cached primary bus from Gavin Shan
 - eeh: Fix stale PE primary bus from Gavin Shan
 - mm: Fix Multi hit ERAT cause by recent THP update from Aneesh Kumar K.V
 - ioda: Set "read" permission when "write" is set from Alexey Kardashevskiy

* tag 'powerpc-4.5-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/ioda: Set "read" permission when "write" is set
  powerpc/mm: Fix Multi hit ERAT cause by recent THP update
  powerpc/powernv: Fix stale PE primary bus
  powerpc/eeh: Fix stale cached primary bus
  powerpc/pseries: Don't trace hcalls on offline CPUs
  powerpc: Fix dedotify for binutils >= 2.26
  powerpc/book3s_32: Fix build error with checkpoint restart

Pull dmaengine fixes from Vinod Koul:
 "A few fixes for drivers, nothing major here.

  Fixes are: iotdma fix to restart channels, new ID for wildcat PCH,
  residue fix for edma, disable irq for non-cyclic in dw"

* tag 'dmaengine-fix-4.5-rc5' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: dw: disable BLOCK IRQs for non-cyclic xfer
  dmaengine: edma: fix residue race for cyclic
  dmaengine: dw: pci: add ID for WildcatPoint PCH
  dmaengine: IOATDMA: fix timer code that continues to restart channels during idle

Pull clk driver fixes from Stephen Boyd:
 "An assortment of vendor specific clk drivers fixes, most notably
  fallout from adding Tegra210 and rockchip rk3036/rk3368 drivers this
  cycle.

  There's also the random smattering of sparse/checker fixes, a build
  "fix" to get the Tango clk driver to compile because the Kconfig
  symbol was renamed after the fact, and a clk gpio fix for a patch
  mismerge"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux: (28 commits)
  clk: gpio: Really allow an optional clock= DT property
  Revert "clk: qcom: Specify LE device endianness"
  clk: versatile: mask VCO bits before writing
  clk: tegra: super: Fix sparse warnings for functions not declared as static
  clk: tegra: Fix sparse warnings for functions not declared as static
  clk: tegra: Fix sparse warning for pll_m
  clk: tegra: Use definition for pll_u override bit
  clk: tegra: Fix warning caused by pll_u failing to lock
  clk: tegra: Fix clock sources for Tegra210 EMC
  clk: tegra: Add the APB2APE audio clock on Tegra210
  clk: tegra: Add missing of_node_put()
  clk: tegra: Fix PLLE SS coefficients
  clk: tegra: Fix typos around clearing PLLE bits during enable
  clk: tegra: Do not disable PLLE when under hardware control
  clk: tegra: Fix pllx dyn step calculation
  clk: tegra: pll: Fix potential sleeping-while-atomic
  clk: tegra: Fix the misnaming of nvenc from msenc
  clk: tegra: Fix naming of MISC registers
  clk: tango4: rename ARCH_TANGOX to ARCH_TANGO
  clk: scpi: Fix checking return value of platform_device_register_simple()
  ...

Pull more drm fixes from Dave Airlie:
 "Some more fixes trickled in:

  A bunch of VC4 ones since it's a pretty new driver not much chance of
  regressions, and it fixes GPU resets.

  Also one atomic fix, one set of fixes for a common bug in TTM cleanup,
  and one i915 hotplug fix"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/nouveau: use post-decrement in error handling
  drm/atomic: Allow for holes in connector state, v2.
  drm/i915: Fix hpd live status bits for g4x
  drm/vc4: Use runtime PM to power cycle the device when the GPU hangs.
  drm/vc4: Enable runtime PM.
  drm/vc4: Fix spurious GPU resets due to BO reuse.
  drm/vc4: Drop error message on seqno wait timeouts.
  drm/vc4: Fix -ERESTARTSYS error return from BO waits.
  drm/vc4: Return an ERR_PTR from BO creation instead of NULL.
  drm/vc4: Fix the clear color for the first tile rendered.
  drm/vc4: Validate that WAIT_BO padding is cleared.
  drm/radeon: use post-decrement in error handling
  drm/amdgpu: use post-decrement in error handling

In __request_region, if a conflict with a BUSY and MUXED resource is
detected, then the caller goes to sleep and waits for the resource to be
released.  A pointer on the conflicting resource is kept.  At wake-up
this pointer is used as a parent to retry to request the region.

A first problem is that this pointer might well be invalid (if for
example the conflicting resource have already been freed).  Another
problem is that the next call to __request_region() fails to detect a
remaining conflict.  The previously conflicting resource is passed as a
parameter and __request_region() will look for a conflict among the
children of this resource and not at the resource itself.  It is likely
to succeed anyway, even if there is still a conflict.

Instead, the parent of the conflicting resource should be passed to
__request_region().

As a fix, this patch doesn't update the parent resource pointer in the
case we have to wait for a muxed region right after.
Reported-and-tested-by: NVincent Pelletier <plr.vincent@gmail.com>
Signed-off-by: NSimon Guinot <simon.guinot@sequanux.org>
Tested-by: NVincent Donnefort <vdonnefort@gmail.com>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull ext4 bugfixes from Ted Ts'o:
 "Miscellaneous ext4 bug fixes for v4.5"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: fix crashes in dioread_nolock mode
  ext4: fix bh->b_state corruption
  ext4: fix memleak in ext4_readdir()
  ext4: remove unused parameter "newblock" in convert_initialized_extent()
  ext4: don't read blocks from disk after extents being swapped
  ext4: fix potential integer overflow
  ext4: add a line break for proc mb_groups display
  ext4: ioctl: fix erroneous return value
  ext4: fix scheduling in atomic on group checksum failure
  ext4 crypto: move context consistency check to ext4_file_open()
  ext4 crypto: revalidate dentry after adding or removing the key

Pull btrfs fix from Chris Mason:
 "My for-linus-4.5 branch has a btrfs DIO error passing fix.

  I know how much you love DIO, so I'm going to suggest against reading
  it.  We'll follow up with a patch to drop the error arg from
  dio_end_io in the next merge window."

* 'for-linus-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: fix direct IO requests not reporting IO error to user space

Merge fixes from Andrew Morton:
 "10 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm: slab: free kmem_cache_node after destroy sysfs file
  ipc/shm: handle removed segments gracefully in shm_mmap()
  MAINTAINERS: update Kselftest Framework mailing list
  devm_memremap_release(): fix memremap'd addr handling
  mm/hugetlb.c: fix incorrect proc nr_hugepages value
  mm, x86: fix pte_page() crash in gup_pte_range()
  fsnotify: turn fsnotify reaper thread into a workqueue job
  Revert "fsnotify: destroy marks with call_srcu instead of dedicated thread"
  mm: fix regression in remap_file_pages() emulation
  thp, dax: do not try to withdraw pgtable from non-anon VMA

Pull arm64 fixes from Will Deacon:
 "Here are some more arm64 fixes for 4.5.  This has mostly come from
  Yang Shi, who saw some issues under -rt that also affect mainline.
  The rest of it is pretty small, but still worth having.

  We've got an old issue outstanding with valid_user_regs which will
  likely wait until 4.6 (since it would really benefit from some time in
  -next) and another issue with kasan and idle which should be fixed
  next week.

  Apart from that, pretty quiet here (and still no sign of the THP issue
  reported on s390...)

  Summary:

   - Allow EFI stub to use strnlen(), which is required by recent libfdt

   - Avoid smp_processor_id() in preempt context during unwinding

   - Avoid false Kasan warnings during unwinding

   - Ensure early devices are picked up by the IOMMU DMA ops

   - Avoid rebuilding the kernel for the 'install' target

   - Run fixup handlers for alignment faults on userspace access"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: mm: allow the kernel to handle alignment faults on user accesses
  arm64: kbuild: make "make install" not depend on vmlinux
  arm64: dma-mapping: fix handling of devices registered before arch_initcall
  arm64/efi: Make strnlen() available to the EFI namespace
  arm/arm64: crypto: assure that ECB modes don't require an IV
  arm64: make irq_stack_ptr more robust
  arm64: debug: re-enable irqs before sending breakpoint SIGTRAP
  arm64: disable kasan when accessing frame->fp in unwind_frame

Pull s390 fixes from Martin Schwidefsky:
 "Several bug fixes:

   - There are four different stack tracers, and three of them have
     bugs.  For 4.5 the bugs are fixed and we prepare a cleanup patch
     for the next merge window.

   - Three bug fixes for the dasd driver in regard to parallel access
     volumes and the new max_dev_sectors block device queue limit

   - The irq restore optimization needs a fixup for memcpy_real

   - The diagnose trace code has a conflict with lockdep"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/dasd: fix performance drop
  s390/maccess: reduce stnsm instructions
  s390/diag: avoid lockdep recursion
  s390/dasd: fix refcount for PAV reassignment
  s390/dasd: prevent incorrect length error under z/VM after PAV changes
  s390: fix DAT off memory access, e.g. on kdump
  s390/oprofile: fix address range for asynchronous stack
  s390/perf_event: fix address range for asynchronous stack
  s390/stacktrace: add save_stack_trace_regs()
  s390/stacktrace: save full stack traces
  s390/stacktrace: add missing end marker
  s390/stacktrace: fix address ranges for asynchronous and panic stack
  s390/stacktrace: fix save_stack_trace_tsk() for current task

Pull Pin control fixes from Linus Walleij:
 "Pin control fixes for the v4.5 series, all are individual driver
  fixes:

   - Fix the PXA2xx driver to export its init function so we do not
     break modular compiles.
   - Hide unused functions in the Nomadik driver.
   - Fix up direction control in the Mediatek driver.
   - Toggle the sunxi GPIO lines to input when you read them on the H3
     GPIO controller, lest you only get garbage.
   - Fix up the number of settings in the MVEBU driver.
   - Fix a serious SMP race condition in the Samsung driver"

* tag 'pinctrl-v4.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
  pinctrl: samsung: fix SMP race condition
  pinctrl: mvebu: fix num_settings in mpp group assignment
  pinctrl: sunxi: H3 requires irq_read_needs_mux
  pinctrl: mediatek: fix direction control issue
  pinctrl: nomadik: hide unused functions
  pinctrl: pxa: export pxa2xx_pinctrl_init()

Pull sound fixes from Takashi Iwai:
 "This update contains again a few more fixes for ALSA core stuff
  although it's no longer high flux: two race fixes in sequencer and one
  PCM race fix for non-atomic PCM ops.

  In addition, HD-audio gained a similar fix for race at reloading the
  driver"

* tag 'sound-4.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: pcm: Fix rwsem deadlock for non-atomic PCM stream
  ALSA: seq: Fix double port list deletion
  ALSA: hda - Cancel probe work instead of flush at remove
  ALSA: seq: Fix leak of pool buffer at concurrent writes

Although we don't expect to take alignment faults on access to normal
memory, misbehaving (i.e. buggy) user code can pass MMIO pointers into
system calls, leading to things like get_user accessing device memory.

Rather than OOPS the kernel, allow any exception fixups to run and
return something like -EFAULT back to userspace. This makes the
behaviour more consistent with userspace, even though applications with
access to device mappings can easily cause other issues if they try
hard enough.
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NEun Taik Lee <eun.taik.lee@samsung.com>
[will: dropped __kprobes annotation and rewrote commit mesage]
Signed-off-by: NWill Deacon <will.deacon@arm.com>

For the same reason as commit 19514fc6 ("arm, kbuild: make "make
install" not depend on vmlinux"), the install targets should never
trigger the rebuild of the kernel.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Competing overwrite DIO in dioread_nolock mode will just overwrite
pointer to io_end in the inode. This may result in data corruption or
extent conversion happening from IO completion interrupt because we
don't properly set buffer_defer_completion() when unlocked DIO races
with locked DIO to unwritten extent.

Since unlocked DIO doesn't need io_end for anything, just avoid
allocating it and corrupting pointer from inode for locked DIO.
A cleaner fix would be to avoid these games with io_end pointer from the
inode but that requires more intrusive changes so we leave that for
later.

Cc: stable@vger.kernel.org
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

ext4 can update bh->b_state non-atomically in _ext4_get_block() and
ext4_da_get_block_prep(). Usually this is fine since bh is just a
temporary storage for mapping information on stack but in some cases it
can be fully living bh attached to a page. In such case non-atomic
update of bh->b_state can race with an atomic update which then gets
lost. Usually when we are mapping bh and thus updating bh->b_state
non-atomically, nobody else touches the bh and so things work out fine
but there is one case to especially worry about: ext4_finish_bio() uses
BH_Uptodate_Lock on the first bh in the page to synchronize handling of
PageWriteback state. So when blocksize < pagesize, we can be atomically
modifying bh->b_state of a buffer that actually isn't under IO and thus
can race e.g. with delalloc trying to map that buffer. The result is
that we can mistakenly set / clear BH_Uptodate_Lock bit resulting in the
corruption of PageWriteback state or missed unlock of BH_Uptodate_Lock.

Fix the problem by always updating bh->b_state bits atomically.

CC: stable@vger.kernel.org
Reported-by: NNikolay Borisov <kernel@kyup.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

We need to use post-decrement to get the dma_map_page undone also for
i==0, and to avoid some very unpleasant behaviour if dma_map_page
failed already at i==0.
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: NBen Skeggs <bskeggs@redhat.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Because we record connector_mask using 1 << drm_connector_index now
the connector_mask should stay the same even when other connectors
are removed. This was not the case with MST, in that case when removing
a connector all other connectors may change their index.

This is fixed by waiting until the first get_connector_state to allocate
connector_state, and force reallocation when state is too small.

As a side effect connector arrays no longer have to be preallocated,
and can be allocated on first use which means a less allocations in
the page flip only path.

Changes since v1:
- Whitespace. (Ville)
- Call ida_remove when destroying the connector. (Ville)
- u32 alloc -> int. (Ville)

Fixes: 14de6c44 ("drm/atomic: Remove drm_atomic_connectors_for_crtc.")
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NLyude <cpaul@redhat.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

We mis-merged the original patch from Russell here and so the
patch went almost all the way, except that we still failed to
probe when there wasn't a clocks property in the DT node. Allow
that case by making a negative value from
of_clk_get_parent_count() into "no parents", like the original
patch did.

Fixes: 7ed88aa2 ("clk: fix clk-gpio.c with optional clock= DT property")
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Michael Turquette <mturquette@baylibre.com>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>

This pull request fixes GPU reset (which was disabled shortly after
V3D integration due to build breakage) and waits for idle in the
presence of signals (which X likes to do a lot).

* tag 'drm-vc4-fixes-2016-02-17' of github.com:anholt/linux:
  drm/vc4: Use runtime PM to power cycle the device when the GPU hangs.
  drm/vc4: Enable runtime PM.
  drm/vc4: Fix spurious GPU resets due to BO reuse.
  drm/vc4: Drop error message on seqno wait timeouts.
  drm/vc4: Fix -ERESTARTSYS error return from BO waits.
  drm/vc4: Return an ERR_PTR from BO creation instead of NULL.
  drm/vc4: Fix the clear color for the first tile rendered.
  drm/vc4: Validate that WAIT_BO padding is cleared.

Just two small fixes in the ttm_tt_populate error handling; one for radeon,
one for amdgpu.

* 'drm-fixes-4.5' of git://people.freedesktop.org/~agd5f/linux:
  drm/radeon: use post-decrement in error handling
  drm/amdgpu: use post-decrement in error handling

single g4x hpd fix.

* tag 'drm-intel-fixes-2016-02-18' of git://anongit.freedesktop.org/drm-intel:
  drm/i915: Fix hpd live status bits for g4x

Pull livepatching fixes from Jiri Kosina:

 - regression (from 4.4) fix for ordering issue, introduced by an
   earlier ftrace change, that broke live patching of modules.

   The fix replaces the ftrace module notifier by direct call in order
   to make the ordering guaranteed and well-defined.  The patch, from
   Jessica Yu, has been acked both by Steven and Rusty

 - error message fix from Miroslav Benes

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
  ftrace/module: remove ftrace module notifier
  livepatch: change the error message in asm/livepatch.h header files