In d7e81c26 (clocksource: Add clocksource_register_hz/khz interface) new
interfaces were added which simplify (and optimize) the selection of the
divisor shift/mult constants.  Switch over to using this new interface.
Acked-by: NKevin Hilman <khilman@deeprootsystems.com>
Tested-by: NKevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

In d7e81c26 (clocksource: Add clocksource_register_hz/khz interface) new
interfaces were added which simplify (and optimize) the selection of the
divisor shift/mult constants.  Switch over to using this new interface.
Acked-By: NScott Branden <sbranden@broadcom.com>
Acked-By: NJiandong Zheng <jdzheng@broadcom.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

In d7e81c26 (clocksource: Add clocksource_register_hz/khz interface) new
interfaces were added which simplify (and optimize) the selection of the
divisor shift/mult constants.  Switch over to using this new interface.
Acked-by: NJean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Ensure that no interrupt is pending before registering the clock
event device, and properly initialize the periodic tick in the
->set_mode callback.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The ARM perf_event.c file contains all PMU backends and, as new PMUs
are introduced, will continue to grow.

This patch follows the example of x86 and splits the PMU implementations
into separate files which are then #included back into the main
file. Compile-time guards are added to each PMU file to avoid compiling
in code that is not relevant for the version of the architecture which
we are targetting.
Acked-by: NJean Pihet <j-pihet@ti.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Currently, perf uses the PMU ID as an index into a string table
to look up the name of a given PMU.

This patch encodes the name of a PMU directly into the arm_pmu
structure so that PMU-specific code can be factored out into
separate files.
Acked-by: NJamie Iles <jamie@jamieiles.com>
Acked-by: NJean Pihet <j-pihet@ti.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

In preparation for separating the PMU-specific code, this patch adds
self-contained init functions to each PMU, therefore removing any
PMU-specific knowledge from the PMU-agnostic init_hw_perf_events
function.
Acked-by: NJamie Iles <jamie@jamieiles.com>
Acked-by: NJean Pihet <j-pihet@ti.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Unlike other pmu functions, armv6pmu_pmu_stop is not declared static.
This patch adds the missing keyword.
Acked-by: NJamie Iles <jamie.iles@jamieiles.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

The functions for mapping PMU events (perf, cache and raw) are
common between all PMU types and differ only in the data on which
they operate.

This patch implements common definitions of these mapping functions
and changes the arm_pmu struct to hold pointers to the data which
they require. This is in anticipation of separating out the PMU-specific
code into separate files.
Acked-by: NJamie Iles <jamie.iles@jamieiles.com>
Acked-by: NJean Pihet <j-pihet@ti.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/staging:
  hwmon: (lis3lv02d_i2c) Fix compile warnings
  hwmon: (i5k_amb) Fix compile warning

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen: remove duplicated #include
  xen: x86/32: perform initial startup on initial_page_table

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  arch/tile: fix memchr() not to dereference memory for zero length
  arch/tile: make glibc's sysconf(_SC_NPROCESSORS_CONF) work correctly
  arch/tile: fix rwlock so would-be write lockers don't block new readers

* 'drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  pci root complex: support for tile architecture
  drivers/net/tile/: on-chip network drivers for the tile architecture
  MAINTAINERS: add drivers/char/hvc_tile.c as maintained by tile

* master.kernel.org:/home/rmk/linux-2.6-arm:
  ARM: 6482/2: Fix find_next_zero_bit and related assembly
  ARM: 6490/1: MM: bugfix: initialize spinlock for init_mm.context
  ARM: avoid annoying <4>'s in printk output
  SCSI: arm fas216: fix missing ';'
  ARM: avoid marking decompressor .stack section as having contents
  ARM: 6489/1: thumb2: fix incorrect optimisation in usracc
  ARM: 6488/1: nomadik: prevent sched_clock() wraparound
  ARM: 6484/1: fix compile warning in mm/init.c
  ARM: 6473/1: Small update to ux500 specific L2 cache code
  ARM: improve compiler's ability to optimize page tables
  mx25: fix spi device registration typo
  ARM i.MX27 eukrea: Fix compilation
  ARM i.MX spi: fix compilation for i.MX21
  ARM i.MX pcm037 eet: compile fixes
  ARM i.MX: sdma is merged, so remove #ifdef SDMA_IS_MERGED
  ARM mx3fb: check for DMA engine type
  mach-pcm037_eet: Fix section mismatch for eet_init_devices()

Merge branch 'fbdev-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/fbdev-2.6

* 'fbdev-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/fbdev-2.6:
  sisfb: delete osdef.h
  sisfb: move the CONFIG warning to sis_main.c
  sisfb: replace SiS_SetMemory with memset_io
  sisfb: remove InPort/OutPort wrappers
  sisfb: use CONFIG_FB_SIS_301/315 instead of SIS301/315H
  sisfb: delete redudant #define SIS_LINUX_KERNEL
  sisfb: delete dead SIS_XORG_XF86 code
  sisfb: delete fallback code for pci_map_rom()
  sisfb: delete obsolete PCI ROM bug workaround
  fbdev: Update documentation index file.
  lxfb: Program panel v/h sync output polarity correctly
  fbcmap: integer overflow bug
  fbcmap: cleanup white space in fb_alloc_cmap()
  MAINTAINERS: Add fbdev patchwork entry, tidy up file patterns.
  fbdev: da8xx: punt duplicated FBIO_WAITFORVSYNC define
  fbdev: sh_mobile_lcdcfb: fix bug in reconfig()

* 'sh-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6:
  sh: clkfwk: Build fix for non-legacy CPG changes.
  sh: Use GCC __builtin_prefetch() to implement prefetch().
  sh: fix vsyscall compilation due to .eh_frame issue
  sh: avoid to flush all cache in sys_cacheflush
  sh: clkfwk: Disable init clk op for non-legacy clocks.
  sh: clkfwk: Kill off now unused algo_id in set_rate op.
  sh: clkfwk: Kill off unused clk_set_rate_ex().

* 'for-linus' of git://neil.brown.name/md:
  md: Call blk_queue_flush() to establish flush/fua support
  md/raid1: really fix recovery looping when single good device fails.
  md: fix return value of rdev_size_change()

* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  virtio: fix format of sysfs driver/vendor files
  Char: virtio_console, fix memory leak
  virtio: return correct capacity to users
  module: Update prototype for ref_module (formerly use_module)

When compiling arch/x86/kernel/early_printk_mrst.c with i386
allmodconfig, gcc-4.1.0 generates an out-of-line copy of
__set_fixmap_offset() which contains a reference to
__this_fixmap_does_not_exist which the compiler cannot elide.

Marking __set_fixmap_offset() as __always_inline prevents this.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Feng Tang <feng.tang@intel.com>
Acked-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The recent changes to gfp.h to satisfy sparse broke scripts/gfp-translate.
This patch fixes it up to work with old and new versions of gfp.h .

[akpm@linux-foundation.org: use `grep -q', per WANG Cong]
Signed-off-by: NMel Gorman <mel@csn.ul.ie>
Cc: Namhyung Kim <namhyung@gmail.com>
Reviewed-by: NWANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

reiserfs_unpack() locks the inode mutex with reiserfs_mutex_lock_safe()
to protect against reiserfs lock dependency.  However this protection
requires to have the reiserfs lock to be locked.

This is the case if reiserfs_unpack() is called by reiserfs_ioctl but
not from reiserfs_quota_on() when it tries to unpack tails of quota
files.

Fix the ordering of the two locks in reiserfs_unpack() to fix this
issue.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Reported-by: NMarkus Gapp <markus.gapp@gmx.net>
Reported-by: NJan Kara <jack@suse.cz>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: <stable@kernel.org>		[2.6.36.x]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

According to the comment describing ops_lock in the definition of struct
backlight_device and when comparing with other functions in backlight.c
the mutex must be hold when checking ops to be non-NULL.

Fixes a problem added by c835ee7f ("backlight: Add suspend/resume
support to the backlight core") in Jan 2009.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: NRichard Purdie <rpurdie@linux.intel.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

struct als_data *data is not used in this driver at all.

Also add a missing ">" character for MODULE_AUTHOR.
Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently one pagemap_read() call walks in PAGEMAP_WALK_SIZE bytes (== 512
pages.) But there is a corner case where walk_pmd_range() accidentally
runs over a VMA associated with a hugetlbfs file.

For example, when a process has mappings to VMAs as shown below:

  # cat /proc/<pid>/maps
  ...
  3a58f6d000-3a58f72000 rw-p 00000000 00:00 0
  7fbd51853000-7fbd51855000 rw-p 00000000 00:00 0
  7fbd5186c000-7fbd5186e000 rw-p 00000000 00:00 0
  7fbd51a00000-7fbd51c00000 rw-s 00000000 00:12 8614   /hugepages/test

then pagemap_read() goes into walk_pmd_range() path and walks in the range
0x7fbd51853000-0x7fbd51a53000, but the hugetlbfs VMA should be handled by
walk_hugetlb_range().  Otherwise PMD for the hugepage is considered bad
and cleared, which causes undesirable results.

This patch fixes it by separating pagemap walk range into one PMD.
Signed-off-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit d33b9f45 ("mm: hugetlb: fix hugepage memory leak in
walk_page_range()") introduces a check if a vma is a hugetlbfs one and
later in 5dc37642 ("mm hugetlb: add hugepage support to pagemap") it is
moved under #ifdef CONFIG_HUGETLB_PAGE but a needless find_vma call is
left behind and its result is not used anywhere else in the function.

The side-effect of caching vma for @addr inside walk->mm is neither
utilized in walk_page_range() nor in called functions.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NAndi Kleen <ak@linux.intel.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Matt Mackall <mpm@selenic.com>
Acked-by: NMel Gorman <mel@csn.ul.ie>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c: fix build_all_zonelist() where percpu_alloc() is wrongly called under stop_machine_run()

During memory hotplug, build_allzonelists() may be called under
stop_machine_run().  In this function, setup_zone_pageset() is called.
But it's bug because it will do page allocation under stop_machine_run().

Here is a report from Alok Kataria.

  BUG: sleeping function called from invalid context at kernel/mutex.c:94
  in_atomic(): 0, irqs_disabled(): 1, pid: 4, name: migration/0
  Pid: 4, comm: migration/0 Not tainted 2.6.35.6-45.fc14.x86_64 #1
  Call Trace:
   [<ffffffff8103d12b>] __might_sleep+0xeb/0xf0
   [<ffffffff81468245>] mutex_lock+0x24/0x50
   [<ffffffff8110eaa6>] pcpu_alloc+0x6d/0x7ee
   [<ffffffff81048888>] ? load_balance+0xbe/0x60e
   [<ffffffff8103a1b3>] ? rt_se_boosted+0x21/0x2f
   [<ffffffff8103e1cf>] ? dequeue_rt_stack+0x18b/0x1ed
   [<ffffffff8110f237>] __alloc_percpu+0x10/0x12
   [<ffffffff81465e22>] setup_zone_pageset+0x38/0xbe
   [<ffffffff810d6d81>] ? build_zonelists_node.clone.58+0x79/0x8c
   [<ffffffff81452539>] __build_all_zonelists+0x419/0x46c
   [<ffffffff8108ef01>] ? cpu_stopper_thread+0xb2/0x198
   [<ffffffff8108f075>] stop_machine_cpu_stop+0x8e/0xc5
   [<ffffffff8108efe7>] ? stop_machine_cpu_stop+0x0/0xc5
   [<ffffffff8108ef57>] cpu_stopper_thread+0x108/0x198
   [<ffffffff81467a37>] ? schedule+0x5b2/0x5cc
   [<ffffffff8108ee4f>] ? cpu_stopper_thread+0x0/0x198
   [<ffffffff81065f29>] kthread+0x7f/0x87
   [<ffffffff8100aae4>] kernel_thread_helper+0x4/0x10
   [<ffffffff81065eaa>] ? kthread+0x0/0x87
   [<ffffffff8100aae0>] ? kernel_thread_helper+0x0/0x10
  Built 5 zonelists in Node order, mobility grouping on.  Total pages: 289456
  Policy zone: Normal

This patch tries to fix the issue by moving setup_zone_pageset() out from
stop_machine_run(). It's obviously not necessary to be called under
stop_machine_run().

[akpm@linux-foundation.org: remove unneeded local]
Reported-by: NAlok Kataria <akataria@vmware.com>
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Petr Vandrovec <petr@vmware.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Reviewed-by: NChristoph Lameter <cl@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Swap accounting can be configured by CONFIG_CGROUP_MEM_RES_CTLR_SWAP
configuration option and then it is turned on by default.  There is a boot
option (noswapaccount) which can disable this feature.

This makes it hard for distributors to enable the configuration option as
this feature leads to a bigger memory consumption and this is a no-go for
general purpose distribution kernel.  On the other hand swap accounting
may be very usuful for some workloads.

This patch adds a new configuration option which controls the default
behavior (CGROUP_MEM_RES_CTLR_SWAP_ENABLED).  If the option is selected
then the feature is turned on by default.

It also adds a new boot parameter swapaccount[=1|0] which enhances the
original noswapaccount parameter semantic by means of enable/disable logic
(defaults to 1 if no value is provided to be still consistent with
noswapaccount).

The default behavior is unchanged (if CONFIG_CGROUP_MEM_RES_CTLR_SWAP is
enabled then CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED is enabled as well)
Signed-off-by: NMichal Hocko <mhocko@suse.cz>
Acked-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

__mem_cgroup_try_charge() can be called under down_write(&mmap_sem)(e.g.
mlock does it). This means it can cause deadlock if it races with move charge:

Ex.1)
                move charge             |        try charge
  --------------------------------------+------------------------------
    mem_cgroup_can_attach()             |  down_write(&mmap_sem)
      mc.moving_task = current          |    ..
      mem_cgroup_precharge_mc()         |  __mem_cgroup_try_charge()
        mem_cgroup_count_precharge()    |    prepare_to_wait()
          down_read(&mmap_sem)          |    if (mc.moving_task)
          -> cannot aquire the lock     |    -> true
                                        |      schedule()

Ex.2)
                move charge             |        try charge
  --------------------------------------+------------------------------
    mem_cgroup_can_attach()             |
      mc.moving_task = current          |
      mem_cgroup_precharge_mc()         |
        mem_cgroup_count_precharge()    |
          down_read(&mmap_sem)          |
          ..                            |
          up_read(&mmap_sem)            |
                                        |  down_write(&mmap_sem)
    mem_cgroup_move_task()              |    ..
      mem_cgroup_move_charge()          |  __mem_cgroup_try_charge()
        down_read(&mmap_sem)            |    prepare_to_wait()
        -> cannot aquire the lock       |    if (mc.moving_task)
                                        |    -> true
                                        |      schedule()

To avoid this deadlock, we do all the move charge works (both can_attach() and
attach()) under one mmap_sem section.
And after this patch, we set/clear mc.moving_task outside mc.lock, because we
use the lock only to check mc.from/to.
Signed-off-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Chip detection may fail if the chip is in some odd state for example after
system restart.  Chip doesn't have HW reset line.
Signed-off-by: NSamu Onkalo <samu.p.onkalo@nokia.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Chip detection may fail if the chip is in some odd state for example after
system restart.  Chip doesn't have HW reset line.
Signed-off-by: NSamu Onkalo <samu.p.onkalo@nokia.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Delays were little bit too long.  Adjust delay times and add some comments
to them.
Signed-off-by: NSamu Onkalo <samu.p.onkalo@nokia.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Delays were little bit too long.  Adjust delay times and add some comments
to them.
Signed-off-by: NSamu Onkalo <samu.p.onkalo@nokia.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A small macro changed to inline function to have proper type checking.
Inline added to two similar small functions.
Signed-off-by: NSamu Onkalo <samu.p.onkalo@nokia.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Some small macros changed to inline functions to have proper type
checking.
Signed-off-by: NSamu Onkalo <samu.p.onkalo@nokia.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The attribute cache for a file was not being cleared when a file is opened
with O_TRUNC.

If the filesystem's open operation truncates the file ("atomic_o_trunc"
feature flag is set) then the kernel should invalidate the cached st_mtime
and st_ctime attributes.

Also i_size should be explicitly be set to zero as it is used sometimes
without refreshing the cache.
Signed-off-by: NKen Sumrall <ksumrall@android.com>
Cc: Anfei <anfei.zhou@gmail.com>
Cc: "Anand V. Avati" <avati@gluster.com>
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

UV hardware defines 256 memory protection regions versus the baseline 64
with increasing size for the SN2 ia64.  This was overlooked when XPC was
modified to accomodate both UV and SN2.

Without this patch, a user could reconfigure their existing system and
suddenly disable cross-partition communications with no indication of what
has gone wrong.  It also prevents larger configurations from using
cross-partition communication.
Signed-off-by: NRobin Holt <holt@sgi.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix this:

  kernel BUG at mm/memcontrol.c:2155!
  invalid opcode: 0000 [#1]
  last sysfs file:

  Pid: 18, comm: sh Not tainted 2.6.37-rc3 #3 /Bochs
  EIP: 0060:[<c10731b2>] EFLAGS: 00000246 CPU: 0
  EIP is at mem_cgroup_move_account+0xe2/0xf0
  EAX: 00000004 EBX: c6f931d4 ECX: c681c300 EDX: c681c000
  ESI: c681c300 EDI: ffffffea EBP: c681c000 ESP: c46f3e30
   DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
  Process sh (pid: 18, ti=c46f2000 task=c6826e60 task.ti=c46f2000)
  Stack:
   00000155 c681c000 0805f000 c46ee180 c46f3e5c c7058820 c1074d37 00000000
   08060000 c46db9a0 c46ec080 c7058820 0805f000 08060000 c46f3e98 c1074c50
   c106c75e c46f3e98 c46ec080 08060000 0805ffff c46db9a0 c46f3e98 c46e0340
  Call Trace:
   [<c1074d37>] ? mem_cgroup_move_charge_pte_range+0xe7/0x130
   [<c1074c50>] ? mem_cgroup_move_charge_pte_range+0x0/0x130
   [<c106c75e>] ? walk_page_range+0xee/0x1d0
   [<c10725d6>] ? mem_cgroup_move_task+0x66/0x90
   [<c1074c50>] ? mem_cgroup_move_charge_pte_range+0x0/0x130
   [<c1072570>] ? mem_cgroup_move_task+0x0/0x90
   [<c1042616>] ? cgroup_attach_task+0x136/0x200
   [<c1042878>] ? cgroup_tasks_write+0x48/0xc0
   [<c1041e9e>] ? cgroup_file_write+0xde/0x220
   [<c101398d>] ? do_page_fault+0x17d/0x3f0
   [<c108a79d>] ? alloc_fd+0x2d/0xd0
   [<c1041dc0>] ? cgroup_file_write+0x0/0x220
   [<c1077ba2>] ? vfs_write+0x92/0xc0
   [<c1077c81>] ? sys_write+0x41/0x70
   [<c1140e3d>] ? syscall_call+0x7/0xb
  Code: 03 00 74 09 8b 44 24 04 e8 1c f1 ff ff 89 73 04 8d 86 b0 00 00 00 b9 01 00 00 00 89 da 31 ff e8 65 f5 ff ff e9 4d ff ff ff 0f 0b <0f> 0b 0f 0b 0f 0b 90 8d b4 26 00 00 00 00 83 ec 10 8b 0d f4 e3
  EIP: [<c10731b2>] mem_cgroup_move_account+0xe2/0xf0 SS:ESP 0068:c46f3e30
  ---[ end trace 7daa1582159b6532 ]---

lock_page_cgroup and unlock_page_cgroup are implemented using
bit_spinlock.  bit_spinlock doesn't touch the bit if we are on non-SMP
machine, so we can't use the bit to check whether the lock was taken.

Let's introduce is_page_cgroup_locked based on bit_spin_is_locked instead
of PageCgroupLocked to fix it.

[akpm@linux-foundation.org: s/is_page_cgroup_locked/page_is_cgroup_locked/]
Signed-off-by: NKirill A. Shutemov <kirill@shutemov.name>
Reviewed-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtisu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>