The NVMe spec recommends using the shutdown normal sequence when safely
taking the controller offline instead of hitting CC.EN on the next
start-up to reset the controller. The spec recommends a minimum of 1
second for the shutdown complete. This patch waits 2 seconds to be on
the safe side.
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>

This combines the controller initialization into one function, removing
IO queue setup from namespace discovery, and creates symetric functions
for device removal. The controller start and shutdown functions can now
be called from resume/suspend context as well as probe/remove.
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>

This separates nvme queue allocation from creation, and queue deletion
from freeing. This is so that we may in the future temporarily disable
queues and reuse the same memory when bringing them back online, like
coming back from suspend state.
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>

This will make it easier to reuse these outside probe/remove.
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>

Flush and discard requests would previously mess up the accounting.
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>

This patch creates the character device as long as a device's admin queues
are usable so a user has an opprotunity to perform administration tasks.
A device may be in a state that does not allow IO and setting the queue
count feature in such a state returns an error. Previously the driver
would bail and the controller would be unusable.
Signed-off-by: NKeith Busch <keith.busch@intel.com>

Signed-off-by: NKeith Busch <keith.busch@intel.com>

The 'Number of Namespaces' read from the device was being treated as
signed, which would cause us to not scan any namespaces for a device
with more than 2 billion namespaces.  That led to noticing that the
namespace ID was also being treated as signed, which could lead to the
result from NVME_IOCTL_ID being treated as an error code.
Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>

Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>

To build user programs that call the NVMe ioctls, we need to have a
user header file.  Catch up to the new way of doing that by splitting
the header file into kernel and uapi portions.
Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>

Since we have the queue locked, it makes sense to check if there are
any completion queue entries on the queue before we release the lock.
If there are, it may save an interrupt and reduce latency for the I/Os
that happened to complete.  This happens fairly often for some workloads.
Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>

I was originally intending to log the fact that the kthread had done
some work since it might help us find interrupt handling problems, but
that hasn't been done yet, and spamming the logs with this message is
just rude.
Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>

The interrupt handler currently reports whether it found any new
completion queue entries.  If the completion queue is primarily being
processed by a method other than the interrupt handler, it may return
IRQ_NONE so often that Linux thinks that the interrupt is being falsely
triggered.

To solve this problem, report whether any completion queue entries have
been seen since the last interrupt was received for this queue.
Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>

Add io stats accounting for bio requests so nvme block devices show
useful disk stats.
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>

The current code copies 'nr_io_queues' into 'q_count', modifies
'nr_io_queues' during MSI-X setup, then resets 'nr_io_queues' for
MSI setup.  Instead, copy 'nr_io_queues' into 'vecs' and modify 'vecs'
during both MSI-X and MSI setup.

This lets us simplify the for-loops that set up MSI-X and MSI, and opens
the possibility of using more I/O queues than we have interrupt vectors,
should future benchmarking prove that to be a useful feature.
Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>

Use kzalloc instead of kmalloc and a susbsequent memset.
Signed-off-by: NTushar Behera <tushar.behera@linaro.org>
Signed-off-by: NVishal Verma <vishal.l.verma@linux.intel.com>
Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>

Pull btrfs fixes from Chris Mason:
 "This is an assortment of crash fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: stop all workers before cleaning up roots
  Btrfs: fix use-after-free bug during umount
  Btrfs: init relocate extent_io_tree with a mapping
  btrfs: Drop inode if inode root is NULL
  Btrfs: don't delete fs_roots until after we cleanup the transaction

Pull device tree bug fixes from Grant Likely:
 "This branch contains the following bug fixes:
   - Fix locking vs. interrupts. Bug caught by lockdep checks
   - Fix parsing of cpp #line directive output by dtc
   - Fix 'make clean' for dtc temporary files.

  There is also a commit that regenerates the dtc lexer and parser files
  with Bison 2.5.  The only purpose of this commit is to separate the
  functional change in the dtc bug fix from the code generation change
  caused by a different Bison version"

* tag 'devicetree-for-linus' of git://git.secretlab.ca/git/linux:
  dtc: ensure #line directives don't consume data from the next line
  dtc: Update generated files to output from Bison 2.5
  of: Fix locking vs. interrupts
  kbuild: make sure we clean up DTB temporary files

Previously, the #line parsing regex ended with ({WS}+[0-9]+)?. The {WS}
could match line-break characters. If the #line directive did not contain
the optional flags field at the end, this could cause any integer data on
the next line to be consumed as part of the #line directive parsing. This
could cause syntax errors (i.e. #line parsing consuming the leading 0
from a hex literal 0x1234, leaving x1234 to be parsed as cell data,
which is a syntax error), or invalid compilation results (i.e. simply
consuming literal 1234 as part of the #line processing, thus removing it
from the cell data).

Fix this by replacing {WS} with [ \t] so that it can't match line-breaks.

Convert all instances of {WS}, even though the other instances should be
irrelevant for any well-formed #line directive. This is done for
consistency and ultimate safety.

[Cherry picked from DTC commit a1ee6f068e1c8dbc62873645037a353d7852d5cc]
Reported-by: NIan Campbell <Ian.Campbell@citrix.com>
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Acked-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

This patch merely updates the generated dtc parser and lexer files to
the output generated by Bison 2.5. The previous versions were generated
from version 2.4.1. The only reason for this commit is to minimize the
diff on the next commit which fixes a bug in the DTC #line directive
parsing. Otherwise the Bison changes would be intermingled with the
functional changes.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

The OF code uses irqsafe locks everywhere except in a handful of functions
for no obvious reasons. Since the conversion from the old rwlocks, this
now triggers lockdep warnings when used at interrupt time. At least one
driver (ibmvscsi) seems to be doing that from softirq context.

This converts the few non-irqsafe locks into irqsafe ones, making them
consistent with the rest of the code.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

Various temporary files used when building DTB files were not suffixed with
.tmp and therefore were not cleaned up by "make clean".
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Reviewed-by: NStephen Warren <swarren@nvidia.com>
Tested-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

Pull ACPI fix from Rafael Wysocki:
 "This is an alternative fix for the regression introduced in 3.9 whose
  previous fix had to be reverted right before 3.10-rc5, because it
  broke one of the Tony's machines.

  In this one the check is confined to the ACPI video driver (which is
  the only one causing the problem to happen in the first place) and the
  Tony's box shouldn't even notice it.

   - ACPI fix for an issue causing ACPI video driver to attempt to bind
     to devices it shouldn't touch from Rafael J Wysocki."

* tag 'acpi-3.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / video: Do not bind to device objects with a scan handler

Pull x86 fixes from Peter Anvin:
 "Another set of fixes, the biggest bit of this is yet another tweak to
  the UEFI anti-bricking code; apparently we finally got some feedback
  from Samsung as to what makes at least their systems fail.  This set
  should actually fix the boot regressions that some other systems (e.g.
  SGI) have exhibited.

  Other than that, there is a patch to avoid a panic with particularly
  unhappy memory layouts and two minor protocol fixes which may or may
  not be manifest bugs"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: Fix typo in kexec register clearing
  x86, relocs: Move __vvar_page from S_ABS to S_REL
  Modify UEFI anti-bricking code
  x86: Fix adjust_range_size_mask calling position

Pull RCU fixes from Paul McKenney:
 "I must confess that this past merge window was not RCU's best showing.
  This series contains three more fixes for RCU regressions:

   1.   A fix to __DECLARE_TRACE_RCU() that causes it to act as an
        interrupt from idle rather than as a task switch from idle.
        This change is needed due to the recent use of _rcuidle()
        tracepoints that can be invoked from interrupt handlers as well
        as from idle.  Without this fix, invoking _rcuidle() tracepoints
        from interrupt handlers results in splats and (more seriously)
        confusion on RCU's part as to whether a given CPU is idle or not.
        This confusion can in turn result in too-short grace periods and
        therefore random memory corruption.

   2.   A fix to a subtle deadlock that could result due to RCU doing
        a wakeup while holding one of its rcu_node structure's locks.
        Although the probability of occurrence is low, it really
        does happen.  The fix, courtesy of Steven Rostedt, uses
        irq_work_queue() to avoid the deadlock.

   3.   A fix to a silent deadlock (invisible to lockdep) due to the
        interaction of timeouts posted by RCU debug code enabled by
        CONFIG_PROVE_RCU_DELAY=y, grace-period initialization, and CPU
        hotplug operations.  This will not occur in production kernels,
        but really does occur in randconfig testing.  Diagnosis courtesy
        of Steven Rostedt"

* 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
  rcu: Fix deadlock with CPU hotplug, RCU GP init, and timer migration
  rcu: Don't call wakeup() with rcu_node structure ->lock held
  trace: Allow idle-safe tracepoints to be called from irq

Pull s390 fixes from Martin Schwidefsky:
 "Three kvm related memory management fixes, a fix for show_trace, a fix
  for early console output and a patch from Ben to help prevent compile
  errors in regard to irq functions (or our lack thereof)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/pci: Implement IRQ functions if !PCI
  s390/sclp: fix new line detection
  s390/pgtable: make pgste lock an explicit barrier
  s390/pgtable: Save pgste during modify_prot_start/commit
  s390/dumpstack: fix address ranges for asynchronous and panic stack
  s390/pgtable: Fix guest overindication for change bit

Pull ASoC sound updates from Mark Brown:
 "Takashi is travelling at the minute and it'd be good to get the
  MAINTAINERS update in here merged so sending directly.

  As well as the usual driver specifics we've got a couple of core fixes
  here, one fixing capabilities for unidirectional streams and the other
  fixing suspend while audio streams are active.

  The suspend fix is a little involved but mostly as a result of
  removing some special casing that was doing the wrong thing."

* tag 'asoc-v3.10-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound:
  ASoC: tlv320aic3x: Remove deadlock from snd_soc_dapm_put_volsw_aic3x()
  ASoC: dapm: Treat DAI widgets like AIF widgets for power
  ASoC: arizona: Correct AEC loopback enable
  ASoC: pcm: Require both CODEC and CPU support when declaring stream caps
  MAINTAINERS: Remove myself from Wolfson maintainers
  ASoC: wm8994: Ensure microphone detection state is reset on removal
  ASoC: wm8994: Avoid leaking pm_runtime reference on removed jack race
  ASoC: cs42l52: fix hp_gain_enum shift value.
  ASoC: cs42l52: use correct PCM mixer TLV dB scale to match datasheet.

Pull md bugfixes from Neil Brown:
 "A few bugfixes for md

  Some tagged for -stable"

* tag 'md-3.10-fixes' of git://neil.brown.name/md:
  md/raid1,5,10: Disable WRITE SAME until a recovery strategy is in place
  md/raid1,raid10: use freeze_array in place of raise_barrier in various places.
  md/raid1: consider WRITE as successful only if at least one non-Faulty and non-rebuilding drive completed it.
  md: md_stop_writes() should always freeze recovery.

On platforms with C8-C10 support, the additional C-states cause
turbostat to overrun its output buffer of 128 bytes per CPU.  Increase
this to 256 bytes per CPU.

[ As a bugfix, this should go into 3.10; however, since the C8-C10
  support didn't go in until after 3.9, this need not go into any stable
  kernel. ]
Signed-off-by: NJosh Triplett <josh@joshtriplett.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

 * More tweaking to the EFI variable anti-bricking algorithm. Quite a
   few users were reporting boot regressions in v3.9. This has now been
   fixed with a more accurate "minimum storage requirement to avoid
   bricking" value from Samsung (5K instead of 50%) and code to trigger
   garbage collection when we near our limit - Matthew Garrett.
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

There are cases where the kernel will believe that the WRITE SAME
command is supported by a block device which does not, in fact,
support WRITE SAME.  This currently happens for SATA drivers behind a
SAS controller, but there are probably a hundred other ways that can
happen, including drive firmware bugs.

After receiving an error for WRITE SAME the block layer will retry the
request as a plain write of zeroes, but mdraid will consider the
failure as fatal and consider the drive failed.  This has the effect
that all the mirrors containing a specific set of data are each
offlined in very rapid succession resulting in data loss.

However, just bouncing the request back up to the block layer isn't
ideal either, because the whole initial request-retry sequence should
be inside the write bitmap fence, which probably means that md needs
to do its own conversion of WRITE SAME to write zero.

Until the failure scenario has been sorted out, disable WRITE SAME for
raid1, raid5, and raid10.

[neilb: added raid5]

This patch is appropriate for any -stable since 3.7 when write_same
support was added.

Cc: stable@vger.kernel.org
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: NNeilBrown <neilb@suse.de>

Various places in raid1 and raid10 are calling raise_barrier when they
really should call freeze_array.
The former is only intended to be called from "make_request".
The later has extra checks for 'nr_queued' and makes a call to
flush_pending_writes(), so it is safe to call it from within the
management thread.

Using raise_barrier will sometimes deadlock.  Using freeze_array
should not.

As 'freeze_array' currently expects one request to be pending (in
handle_read_error - the only previous caller), we need to pass
it the number of pending requests (extra) to ignore.

The deadlock was made particularly noticeable by commits
050b6615 (raid10) and 6b740b8d (raid1) which
appeared in 3.4, so the fix is appropriate for any -stable
kernel since then.

This patch probably won't apply directly to some early kernels and
will need to be applied by hand.

Cc: stable@vger.kernel.org
Reported-by: NAlexander Lyakas <alex.bolshoy@gmail.com>
Signed-off-by: NNeilBrown <neilb@suse.de>

md/raid1: consider WRITE as successful only if at least one non-Faulty and non-rebuilding drive completed it.

Without that fix, the following scenario could happen:

- RAID1 with drives A and B; drive B was freshly-added and is rebuilding
- Drive A fails
- WRITE request arrives to the array. It is failed by drive A, so
r1_bio is marked as R1BIO_WriteError, but the rebuilding drive B
succeeds in writing it, so the same r1_bio is marked as
R1BIO_Uptodate.
- r1_bio arrives to handle_write_finished, badblocks are disabled,
md_error()->error() does nothing because we don't fail the last drive
of raid1
- raid_end_bio_io()  calls call_bio_endio()
- As a result, in call_bio_endio():
        if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
                clear_bit(BIO_UPTODATE, &bio->bi_flags);
this code doesn't clear the BIO_UPTODATE flag, and the whole master
WRITE succeeds, back to the upper layer.

So we returned success to the upper layer, even though we had written
the data onto the rebuilding drive only. But when we want to read the
data back, we would not read from the rebuilding drive, so this data
is lost.

[neilb - applied identical change to raid10 as well]

This bug can result in lost data, so it is suitable for any
-stable kernel.

Cc: stable@vger.kernel.org
Signed-off-by: NAlex Lyakas <alex@zadarastorage.com>
Signed-off-by: NNeilBrown <neilb@suse.de>

__md_stop_writes() will currently sometimes freeze recovery.
So any caller must be ready for that to happen, and indeed they are.

However if __md_stop_writes() doesn't freeze_recovery, then
a recovery could start before mddev_suspend() is called, which
could be awkward.  This can particularly cause problems or dm-raid.

So change __md_stop_writes() to always freeze recovery.  This is safe
and more predicatable.
Reported-by: NBrassow Jonathan <jbrassow@redhat.com>
Tested-by: NBrassow Jonathan <jbrassow@redhat.com>
Signed-off-by: NNeilBrown <neilb@suse.de>

Pull networking update from David Miller:

 1) Fix dump iterator in nfnl_acct_dump() and ctnl_timeout_dump() to
    dump all objects properly, from Pablo Neira Ayuso.

 2) xt_TCPMSS must use the default MSS of 536 when no MSS TCP option is
    present.  Fix from Phil Oester.

 3) qdisc_get_rtab() looks for an existing matching rate table and uses
    that instead of creating a new one.  However, it's key matching is
    incomplete, it fails to check to make sure the ->data[] array is
    identical too.  Fix from Eric Dumazet.

 4) ip_vs_dest_entry isn't fully initialized before copying back to
    userspace, fix from Dan Carpenter.

 5) Fix ubuf reference counting regression in vhost_net, from Jason
    Wang.

 6) When sock_diag dumps a socket filter back to userspace, we have to
    translate it out of the kernel's internal representation first.
    From Nicolas Dichtel.

 7) davinci_mdio holds a spinlock while calling pm_runtime, which
    sleeps.  Fix from Sebastian Siewior.

 8) Timeout check in sh_eth_check_reset is off by one, from Sergei
    Shtylyov.

 9) If sctp socket init fails, we can NULL deref during cleanup.  Fix
    from Daniel Borkmann.

10) netlink_mmap() does not propagate errors properly, from Patrick
    McHardy.

11) Disable powersave and use minstrel by default in ath9k.  From Sujith
    Manoharan.

12) Fix a regression in that SOCK_ZEROCOPY is not set on tuntap sockets
    which prevents vhost from being able to use zerocopy.  From Jason
    Wang.

13) Fix race between port lookup and TX path in team driver, from Jiri
    Pirko.

14) Missing length checks in bluetooth L2CAP packet parsing, from Johan
    Hedberg.

15) rtlwifi fails to connect to networking using any encryption method
    other than WPA2.  Fix from Larry Finger.

16) Fix iwlegacy build due to incorrect CONFIG_* ifdeffing for power
    management stuff.  From Yijing Wang.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (35 commits)
  b43: stop format string leaking into error msgs
  ath9k: Use minstrel rate control by default
  Revert "ath9k_hw: Update rx gain initval to improve rx sensitivity"
  ath9k: Disable PowerSave by default
  net: wireless: iwlegacy: fix build error for il_pm_ops
  rtlwifi: Fix a false leak indication for PCI devices
  wl12xx/wl18xx: scan all 5ghz channels
  wl12xx: increase minimum singlerole firmware version required
  wl12xx: fix minimum required firmware version for wl127x multirole
  rtlwifi: rtl8192cu: Fix problem in connecting to WEP or WPA(1) networks
  mwifiex: debugfs: Fix out of bounds array access
  Bluetooth: Fix mgmt handling of power on failures
  Bluetooth: Fix missing length checks for L2CAP signalling PDUs
  Bluetooth: btmrvl: support Marvell Bluetooth device SD8897
  Bluetooth: Fix checks for LE support on LE-only controllers
  team: fix checks in team_get_first_port_txable_rcu()
  team: move add to port list before port enablement
  team: check return value of team_get_port_by_index_rcu() for NULL
  tuntap: set SOCK_ZEROCOPY flag during open
  netlink: fix error propagation in netlink_mmap()
  ...

Pull input layer bugfix from Jiri Kosina:
 "Memory leak regression fix from Benjamin Tissoires"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
  HID: multitouch: prevent memleak with the allocated name

Pull block layer fixes from Jens Axboe:
 "Outside of bcache (which really isn't super big), these are all
  few-liners.  There are a few important fixes in here:

   - Fix blk pm sleeping when holding the queue lock

   - A small collection of bcache fixes that have been done and tested
     since bcache was included in this merge window.

   - A fix for a raid5 regression introduced with the bio changes.

   - Two important fixes for mtip32xx, fixing an oops and potential data
     corruption (or hang) due to wrong bio iteration on stacked devices."

* 'for-linus' of git://git.kernel.dk/linux-block:
  scatterlist: sg_set_buf() argument must be in linear mapping
  raid5: Initialize bi_vcnt
  pktcdvd: silence static checker warning
  block: remove refs to XD disks from documentation
  blkpm: avoid sleep when holding queue lock
  mtip32xx: Correctly handle bio->bi_idx != 0 conditions
  mtip32xx: Fix NULL pointer dereference during module unload
  bcache: Fix error handling in init code
  bcache: clarify free/available/unused space
  bcache: drop "select CLOSURES"
  bcache: Fix incompatible pointer type warning

Merge misc fixes from Andrew Morton:
 "Bunch of fixes and one little addition to math64.h"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (27 commits)
  include/linux/math64.h: add div64_ul()
  mm: memcontrol: fix lockless reclaim hierarchy iterator
  frontswap: fix incorrect zeroing and allocation size for frontswap_map
  kernel/audit_tree.c:audit_add_tree_rule(): protect `rule' from kill_rules()
  mm: migration: add migrate_entry_wait_huge()
  ocfs2: add missing lockres put in dlm_mig_lockres_handler
  mm/page_alloc.c: fix watermark check in __zone_watermark_ok()
  drivers/misc/sgi-gru/grufile.c: fix info leak in gru_get_config_info()
  aio: fix io_destroy() regression by using call_rcu()
  rtc-at91rm9200: use shadow IMR on at91sam9x5
  rtc-at91rm9200: add shadow interrupt mask
  rtc-at91rm9200: refactor interrupt-register handling
  rtc-at91rm9200: add configuration support
  rtc-at91rm9200: add match-table compile guard
  fs/ocfs2/namei.c: remove unecessary ERROR when removing non-empty directory
  swap: avoid read_swap_cache_async() race to deadlock while waiting on discard I/O completion
  drivers/rtc/rtc-twl.c: fix missing device_init_wakeup() when booted with device tree
  cciss: fix broken mutex usage in ioctl
  audit: wait_for_auditd() should use TASK_UNINTERRUPTIBLE
  drivers/rtc/rtc-cmos.c: fix accidentally enabling rtc channel
  ...

There is div64_long() to handle the s64/long division, but no mocro do
u64/ul division.  It is necessary in some scenarios, so add this
function.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The lockless reclaim hierarchy iterator currently has a misplaced
barrier that can lead to use-after-free crashes.

The reclaim hierarchy iterator consist of a sequence count and a
position pointer that are read and written locklessly, with memory
barriers enforcing ordering.

The write side sets the position pointer first, then updates the
sequence count to "publish" the new position.  Likewise, the read side
must read the sequence count first, then the position.  If the sequence
count is up to date, it's guaranteed that the position is up to date as
well:

  writer:                         reader:
  iter->position = position       if iter->sequence == expected:
  smp_wmb()                           smp_rmb()
  iter->sequence = sequence           position = iter->position

However, the read side barrier is currently misplaced, which can lead to
dereferencing stale position pointers that no longer point to valid
memory.  Fix this.
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Reported-by: NTejun Heo <tj@kernel.org>
Reviewed-by: NTejun Heo <tj@kernel.org>
Acked-by: NMichal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: <stable@kernel.org>		[3.10+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>