The sysctl knob sysctl_vfs_cache_pressure is used to determine which
percentage of the shrinkable objects in our cache we should actively try
to shrink.

It works great in situations in which we have many objects (at least more
than 100), because the aproximation errors will be negligible.  But if
this is not the case, specially when total_objects < 100, we may end up
concluding that we have no objects at all (total / 100 = 0, if total <
100).

This is certainly not the biggest killer in the world, but may matter in
very low kernel memory situations.
Signed-off-by: Glauber Costa <glommer@openvz.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Rientjes <rientjes@google.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: J. Bruce Fields <bfields@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

This series reworks our current object cache shrinking infrastructure in
two main ways:

 * Noticing that a lot of users copy and paste their own version of LRU
   lists for objects, we put some effort in providing a generic version.
   It is modeled after the filesystem users: dentries, inodes, and xfs
   (for various tasks), but we expect that other users could benefit in
   the near future with little or no modification.  Let us know if you
   have any issues.

 * The underlying list_lru being proposed automatically and
   transparently keeps the elements in per-node lists, and is able to
   manipulate the node lists individually.  Given this infrastructure, we
   are able to modify the up-to-now hammer called shrink_slab to proceed
   with node-reclaim instead of always searching memory from all over like
   it has been doing.

Per-node lru lists are also expected to lead to less contention in the lru
locks on multi-node scans, since we are now no longer fighting for a
global lock.  The locks usually disappear from the profilers with this
change.

Although we have no official benchmarks for this version - be our guest to
independently evaluate this - earlier versions of this series were
performance tested (details at
http://permalink.gmane.org/gmane.linux.kernel.mm/100537) yielding no
visible performance regressions while yielding a better qualitative
behavior in NUMA machines.

With this infrastructure in place, we can use the list_lru entry point to
provide memcg isolation and per-memcg targeted reclaim.  Historically,
those two pieces of work have been posted together.  This version presents
only the infrastructure work, deferring the memcg work for a later time,
so we can focus on getting this part tested.  You can see more about the
history of such work at http://lwn.net/Articles/552769/

Dave Chinner (18):
  dcache: convert dentry_stat.nr_unused to per-cpu counters
  dentry: move to per-sb LRU locks
  dcache: remove dentries from LRU before putting on dispose list
  mm: new shrinker API
  shrinker: convert superblock shrinkers to new API
  list: add a new LRU list type
  inode: convert inode lru list to generic lru list code.
  dcache: convert to use new lru list infrastructure
  list_lru: per-node list infrastructure
  shrinker: add node awareness
  fs: convert inode and dentry shrinking to be node aware
  xfs: convert buftarg LRU to generic code
  xfs: rework buffer dispose list tracking
  xfs: convert dquot cache lru to list_lru
  fs: convert fs shrinkers to new scan/count API
  drivers: convert shrinkers to new count/scan API
  shrinker: convert remaining shrinkers to count/scan API
  shrinker: Kill old ->shrink API.

Glauber Costa (7):
  fs: bump inode and dentry counters to long
  super: fix calculation of shrinkable objects for small numbers
  list_lru: per-node API
  vmscan: per-node deferred work
  i915: bail out earlier when shrinker cannot acquire mutex
  hugepage: convert huge zero page shrinker to new shrinker API
  list_lru: dynamically adjust node arrays

This patch:

There are situations in very large machines in which we can have a large
quantity of dirty inodes, unused dentries, etc.  This is particularly true
when umounting a filesystem, where eventually since every live object will
eventually be discarded.

Dave Chinner reported a problem with this while experimenting with the
shrinker revamp patchset.  So we believe it is time for a change.  This
patch just moves int to longs.  Machines where it matters should have a
big long anyway.
Signed-off-by: Glauber Costa <glommer@openvz.org>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: J. Bruce Fields <bfields@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Dave Jones <davej@fedoraproject.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

For a long time no filesystem has been using vfs_follow_link, and as seen
by recent filesystem submissions any new use is accidental as well.

Remove vfs_follow_link, document the replacement in
Documentation/filesystems/porting and also rename __vfs_follow_link
to match its only caller better.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull vfs pile 3 (of many) from Al Viro:
 "Waiman's conversion of d_path() and bits related to it,
  kern_path_mountpoint(), several cleanups and fixes (exportfs
  one is -stable fodder, IMO).

  There definitely will be more...  ;-/"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  split read_seqretry_or_unlock(), convert d_walk() to resulting primitives
  dcache: Translating dentry into pathname without taking rename_lock
  autofs4 - fix device ioctl mount lookup
  introduce kern_path_mountpoint()
  rename user_path_umountat() to user_path_mountpoint_at()
  take unlazy_walk() into umount_lookup_last()
  Kill indirect include of file.h from eventfd.h, use fdget() in cgroup.c
  prune_super(): sb->s_op is never NULL
  exportfs: don't assume that ->iterate() won't feed us too long entries
  afs: get rid of redundant ->d_name.len checks

When I moved the RCU walk termination into unlazy_walk(), I didn't copy
quite all of it: for the successful RCU termination we properly add the
necessary reference counts to our temporary copy of the root path, but
for the failure case we need to make sure that any temporary root path
information is cleared out (since it does _not_ have the proper
reference counts from the RCU lookup).

We could clean up this mess by just always dropping the temporary root
information, but Al points out that that would mean that a single lookup
through symlinks could see multiple different root entries if it races
with another thread doing chroot.  Not that I think we should really
care (we had that before too, back before we had a copy of the root path
in the nameidata).

Al says he has a cunning plan.  In the meantime, this is the minimal fix
for the problem, even if it's not all that pretty.
Reported-by: Mace Moneta <moneta.mace@gmail.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull dmaengine update from Dan Williams:
 "Collection of random updates to the core and some end-driver fixups
  for ioatdma and mv_xor:
   - NUMA aware channel allocation
   - Cleanup dmatest debugfs interface
   - ioat: make raid-support Atom only
   - mv_xor: big endian

  Aside from the top three commits these have all had some soak time in
  -next.  The top commit fixes a recent build breakage.

  It has been a long while since my last pull request, hopefully it does
  not show.  Thanks to Vinod for keeping an eye on drivers/dma/ this
  past year"

* tag 'dmaengine-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/dmaengine:
  dmaengine: dma_sync_wait and dma_find_channel undefined
  MAINTAINERS: update email for Dan Williams
  dma: mv_xor: Fix incorrect error path
  ioatdma: silence GCC warnings
  dmaengine: make dma_channel_rebalance() NUMA aware
  dmaengine: make dma_submit_error() return an error code
  ioatdma: disable RAID on non-Atom platforms and reenable unaligned copies
  mv_xor: support big endian systems using descriptor swap feature
  mv_xor: use {readl, writel}_relaxed instead of __raw_{readl, writel}
  dmatest: print message on debug level in case of no error
  dmatest: remove IS_ERR_OR_NULL checks of debugfs calls
  dmatest: make module parameters writable

dma_sync_wait and dma_find_channel are declared regardless of whether
CONFIG_DMA_ENGINE is enabled, but calling the function without
CONFIG_DMA_ENGINE enabled results "undefined reference" errors.

To get around this, declare dma_sync_wait and dma_find_channel as inline
functions if CONFIG_DMA_ENGINE is undefined.
Signed-off-by: Jon Mason <jon.mason@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Pull ARM SoC late changes from Kevin Hilman:
 "These are changes that arrived a little late before the merge window,
  or had dependencies on previous branches.

  Highlights:
   - ux500: misc.  cleanup, fixup I2C devices
   - exynos: DT updates for RTC; PM updates
   - at91: DT updates for NAND; new platforms added to generic defconfig
   - sunxi: DT updates: cubieboard2, pinctrl driver, gated clocks
   - highbank: LPAE fixes, select necessary ARM errata
   - omap: PM fixes and improvements; OMAP5 mailbox support
   - omap: basic support for new DRA7xx SoCs"

* tag 'late-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (60 commits)
  ARM: dts: vexpress: Add CCI node to TC2 device-tree
  ARM: EXYNOS: Skip C1 cpuidle state for exynos5440
  ARM: EXYNOS: always enable PM domains support for EXYNOS4X12
  ARM: highbank: clean-up some unused includes
  ARM: sun7i: Enable the A20 clocks in the DTSI
  ARM: sun6i: Enable clock support in the DTSI
  ARM: sun5i: dt: Use the A10s gates in the DTSI
  ARM: at91: at91_dt_defconfig: enable rm9200 support
  ARM: dts: add ADC device tree node for exynos5420/5250
  ARM: dts: Add RTC DT node to Exynos5420 SoC
  ARM: dts: Update the "status" property of RTC DT node for Exynos5250 SoC
  ARM: dts: Fix the RTC DT node name for Exynos5250
  irqchip: mmp: avoid to include irqs head file
  ARM: mmp: avoid to include head file in mach-mmp
  irqchip: mmp: support irqchip
  irqchip: move mmp irq driver
  ARM: OMAP: AM33xx: clock: Add RNG clock data
  ARM: OMAP: TI81XX: add always-on powerdomain for TI81XX
  ARM: OMAP4: clock: Lock PLLs in the right sequence
  ARM: OMAP: AM33XX: hwmod: Add hwmod data for debugSS
  ...

Pull ARM Renesas SoC cleanup, refactoring and more SMP support from Kevin Hilman:
 "Lots of cleanup and refactoring and some SMP additions for Renesas
  platforms.  Due to some inter-dependencies with other arm-soc
  branches, this Renesas stuff was separated out for sending after the
  other branches were merged.

  Highlights:
   - remove unused board support and cleanup of unused headers
   - refactoring of init and device registration
   - simplify IRQ initialization"

* tag 'renesas-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (68 commits)
  ARM: shmobile: Per-CPU SMP boot / sleep code for SCU SoCs
  ARM: shmobile: Introduce per-CPU SMP boot / sleep code
  ARM: shmobile: Use shared SCU CPU Hotplug code on r8a7779
  ARM: shmobile: Use shared SCU CPU Hotplug code on sh73a0
  ARM: shmobile: Add shared SCU CPU Hotplug code
  ARM: shmobile: Use shared SCU SMP boot code on emev2
  ARM: shmobile: Use shared SCU SMP boot code on r8a7779
  ARM: shmobile: Use shared SCU SMP boot code on sh73a0
  ARM: shmobile: Introduce shared SCU SMP boot code
  ARM: shmobile: sh73a0: Remove global GPIO_NR definition
  ARM: shmobile: kzm9d: remove nfsroot settings from bootargs
  ARM: shmobile: armadillo800eva: remove nfsroot settings from bootargs
  ARM: shmobile: r8a7779: move r8a7779_init_irq_xxx() to setup
  ARM: shmobile: r8a7740: move r8a7740_init_irq_of() to setup
  ARM: shmobile: bockw: add missing __initdata
  ARM: shmobile: r8a7790: add missing __initdata
  ARM: shmobile: r8a7779: add missing __initdata
  ARM: shmobile: Remove unused shmobile_init_time()
  ARM: shmobile: Use clocksource_of_init() on r8a7790
  ARM: shmobile: Use default ->init_time() on KZM9G DT ref
  ...

Pull ARM SoC driver update from Kevin Hilman:
 "This contains the ARM SoC related driver updates for v3.12.  The only
  thing this cycle are core PM updates and CPUidle support for ARM's TC2
  big.LITTLE development platform"

* tag 'drivers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  cpuidle: big.LITTLE: vexpress-TC2 CPU idle driver
  ARM: vexpress: tc2: disable GIC CPU IF in tc2_pm_suspend
  drivers: irq-chip: irq-gic: introduce gic_cpu_if_down()

Pull clock framework changes from Michael Turquette:
 "The common clk framework changes for 3.12 are dominated by clock
  driver patches, both new drivers and fixes to existing.  A high
  percentage of these are for Samsung platforms like Exynos.  Core
  framework fixes and some new features like automagical clock
  re-parenting round out the patches"

* tag 'clk-for-linus-3.12' of git://git.linaro.org/people/mturquette/linux: (102 commits)
  clk: only call get_parent if there is one
  clk: samsung: exynos5250: Simplify registration of PLL rate tables
  clk: samsung: exynos4: Register PLL rate tables for Exynos4x12
  clk: samsung: exynos4: Register PLL rate tables for Exynos4210
  clk: samsung: exynos4: Reorder registration of mout_vpllsrc
  clk: samsung: pll: Add support for rate configuration of PLL46xx
  clk: samsung: pll: Use new registration method for PLL46xx
  clk: samsung: pll: Add support for rate configuration of PLL45xx
  clk: samsung: pll: Use new registration method for PLL45xx
  clk: samsung: exynos4: Rename exynos4_plls to exynos4x12_plls
  clk: samsung: exynos4: Remove checks for DT node
  clk: samsung: exynos4: Remove unused static clkdev aliases
  clk: samsung: Modify _get_rate() helper to use __clk_lookup()
  clk: samsung: exynos4: Use separate aliases for cpufreq related clocks
  clocksource: samsung_pwm_timer: Get clock from device tree
  ARM: dts: exynos4: Specify PWM clocks in PWM node
  pwm: samsung: Update DT bindings documentation to cover clocks
  clk: Move symbol export to proper location
  clk: fix new_parent dereference before null check
  clk: wm831x: Initialise wm831x pointer on init
  ...

Pull tracing updates from Steven Rostedt:
 "Not much changes for the 3.12 merge window.  The major tracing changes
  are still in flux, and will have to wait for 3.13.

  The changes for 3.12 are mostly clean ups and minor fixes.

  H Peter Anvin added a check to x86_32 static function tracing that
  helps a small segment of the kernel community.

  Oleg Nesterov had a few changes from 3.11, but were mostly clean ups
  and not worth pushing in the -rc time frame.

  Li Zefan had small clean up with annotating a raw_init with __init.

  I fixed a slight race in updating function callbacks, but the race is
  so small and the bug that happens when it occurs is so minor it's not
  even worth pushing to stable.

  The only real enhancement is from Alexander Z Lam that made the
  tracing_cpumask work for trace buffer instances, instead of them all
  sharing a global cpumask"

* tag 'trace-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace/rcu: Do not trace debug_lockdep_rcu_enabled()
  x86-32, ftrace: Fix static ftrace when early microcode is enabled
  ftrace: Fix a slight race in modifying what function callback gets traced
  tracing: Make tracing_cpumask available for all instances
  tracing: Kill the !CONFIG_MODULES code in trace_events.c
  tracing: Don't pass file_operations array to event_create_dir()
  tracing: Kill trace_create_file_ops() and friends
  tracing/syscalls: Annotate raw_init function with __init

In __clk_init(), after a clock is mostly initialized, a scan is done
of the orphan clocks to see if the clock being registered is the
parent of any of them.

This code assumes that any clock that provides a get_parent method
actually has at least one parent, and that's not a valid assumption.

As a result, an orphan clock with no parent can return *something*
as the parent index, and that value is blindly used to dereference
the orphan's parent_names[] array (which will be ZERO_SIZE_PTR or
NULL).

Fix this by ensuring get_parent is only called for orphans with at
least one parent.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

Separate "check if we need to retry" from "unlock if we are done and
had seq_writelock"; that allows to use these guys in d_walk(), where
we need to recheck every time we ascend back to parent, but do *not*
want to unlock until the very end.  Lift rcu_read_lock/rcu_read_unlock
out into callers.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull xfs updates from Ben Myers:
 "For 3.12-rc1 there are a number of bugfixes in addition to work to
  ease usage of shared code between libxfs and the kernel, the rest of
  the work to enable project and group quotas to be used simultaneously,
  performance optimisations in the log and the CIL, directory entry file
  type support, fixes for log space reservations, some spelling/grammar
  cleanups, and the addition of user namespace support.

   - introduce readahead to log recovery
   - add directory entry file type support
   - fix a number of spelling errors in comments
   - introduce new Q_XGETQSTATV quotactl for project quotas
   - add USER_NS support
   - log space reservation rework
   - CIL optimisations
  - kernel/userspace libxfs rework"

* tag 'xfs-for-linus-v3.12-rc1' of git://oss.sgi.com/xfs/xfs: (112 commits)
  xfs: XFS_MOUNT_QUOTA_ALL needed by userspace
  xfs: dtype changed xfs_dir2_sfe_put_ino to xfs_dir3_sfe_put_ino
  Fix wrong flag ASSERT in xfs_attr_shortform_getvalue
  xfs: finish removing IOP_* macros.
  xfs: inode log reservations are too small
  xfs: check correct status variable for xfs_inobt_get_rec() call
  xfs: inode buffers may not be valid during recovery readahead
  xfs: check LSN ordering for v5 superblocks during recovery
  xfs: btree block LSN escaping to disk uninitialised
  XFS: Assertion failed: first <= last && last < BBTOB(bp->b_length), file: fs/xfs/xfs_trans_buf.c, line: 568
  xfs: fix bad dquot buffer size in log recovery readahead
  xfs: don't account buffer cancellation during log recovery readahead
  xfs: check for underflow in xfs_iformat_fork()
  xfs: xfs_dir3_sfe_put_ino can be static
  xfs: introduce object readahead to log recovery
  xfs: Simplify xfs_ail_min() with list_first_entry_or_null()
  xfs: Register hotcpu notifier after initialization
  xfs: add xfs sb v4 support for dirent filetype field
  xfs: Add write support for dirent filetype field
  xfs: Add read-only support for dirent filetype field
  ...

Not using the return value can in the generic case be racy, so it's
in general good practice to check the return value instead.

This also resolved the warning caused on ARM and other architectures:

  fs/direct-io.c: In function 'sb_init_dio_done_wq':
  fs/direct-io.c:557:2: warning: value computed is not used [-Wunused-value]
Signed-off-by: Olof Johansson <olof@lixom.net>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: H Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When running the AIM7's short workload, Linus' lockref patch eliminated
most of the spinlock contention. However, there were still some left:

     8.46%     reaim  [kernel.kallsyms]     [k] _raw_spin_lock
                 |--42.21%-- d_path
                 |          proc_pid_readlink
                 |          SyS_readlinkat
                 |          SyS_readlink
                 |          system_call
                 |          __GI___readlink
                 |
                 |--40.97%-- sys_getcwd
                 |          system_call
                 |          __getcwd

The big one here is the rename_lock (seqlock) contention in d_path()
and the getcwd system call. This patch will eliminate the need to take
the rename_lock while translating dentries into the full pathnames.

The need to take the rename_lock is to make sure that no rename
operation can be ongoing while the translation is in progress. However,
only one thread can take the rename_lock thus blocking all the other
threads that need it even though the translation process won't make
any change to the dentries.

This patch will replace the writer's write_seqlock/write_sequnlock
sequence of the rename_lock of the callers of the prepend_path() and
__dentry_path() functions with the reader's read_seqbegin/read_seqretry
sequence within these 2 functions. As a result, the code will have to
retry if one or more rename operations had been performed. In addition,
RCU read lock will be taken during the translation process to make sure
that no dentries will go away. To prevent live-lock from happening,
the code will switch back to take the rename_lock if read_seqretry()
fails for three times.

To further reduce spinlock contention, this patch does not take the
dentry's d_lock when copying the filename from the dentries. Instead,
it treats the name pointer and length as unreliable and just copy
the string byte-by-byte over until it hits a null byte or the end of
string as specified by the length. This should avoid stepping into
invalid memory address. The error cases are left to be handled by
the sequence number check.

The following code re-factoring are also made:
1. Move prepend('/') into prepend_name() to remove one conditional
   check.
2. Move the global root check in prepend_path() back to the top of
   the while loop.

With this patch, the _raw_spin_lock will now account for only 1.2%
of the total CPU cycles for the short workload. This patch also has
the effect of reducing the effect of running perf on its profile
since the perf command itself can be a heavy user of the d_path()
function depending on the complexity of the workload.

When taking the perf profile of the high-systime workload, the amount
of spinlock contention contributed by running perf without this patch
was about 16%. With this patch, the spinlock contention caused by
the running of perf will go away and we will have a more accurate
perf profile.
Signed-off-by: Waiman Long <Waiman.Long@hp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull mtd updates from David Woodhouse:
 - factor out common code from MTD tests
 - nand-gpio cleanup and portability to non-ARM
 - m25p80 support for 4-byte addressing chips, other new chips
 - pxa3xx cleanup and support for new platforms
 - remove obsolete alauda, octagon-5066 drivers
 - erase/write support for bcm47xxsflash
 - improve detection of ECC requirements for NAND, controller setup
 - NFC acceleration support for atmel-nand, read/write via SRAM
 - etc

* tag 'for-linus-20130909' of git://git.infradead.org/linux-mtd: (184 commits)
  mtd: chips: Add support for PMC SPI Flash chips in m25p80.c
  mtd: ofpart: use for_each_child_of_node() macro
  mtd: mtdswap: replace strict_strtoul() with kstrtoul()
  mtd cs553x_nand: use kzalloc() instead of memset
  mtd: atmel_nand: fix error return code in atmel_nand_probe()
  mtd: bcm47xxsflash: writing support
  mtd: bcm47xxsflash: implement erasing support
  mtd: bcm47xxsflash: convert to module_platform_driver instead of init/exit
  mtd: bcm47xxsflash: convert kzalloc to avoid invalid access
  mtd: remove alauda driver
  mtd: nand: mxc_nand: mark 'const' properly
  mtd: maps: cfi_flagadm: add missing __iomem annotation
  mtd: spear_smi: add missing __iomem annotation
  mtd: r852: Staticize local symbols
  mtd: nandsim: Staticize local symbols
  mtd: impa7: add missing __iomem annotation
  mtd: sm_ftl: Staticize local symbols
  mtd: m25p80: add support for mr25h10
  mtd: m25p80: make CONFIG_M25PXX_USE_FAST_READ safe to enable
  mtd: m25p80: Pass flags through CAT25_INFO macro
  ...

Pull firewire updates from Stefan Richter:

 - Fix a regression since 3.2 inclusive: The subsystem workqueue
   deadlocked between transaction completion handling and bus reset
   handling if the worker pool could not be increased in time.

 - janitorial updates

* tag 'firewire-updates' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394:
  firewire: ohci: Fix deadlock at bus reset
  firewire: ohci: Change module_pci_driver to module_init/module_exit
  firewire: ohci: beautify some macro definitions
  firewire: ohci: change confusing name of a struct member
  firewire: core: typecast from gfp_t to bool more safely
  firewire: WQ_NON_REENTRANT is meaningless and going away

Returned to intel.com

Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Jon Mason <jon.mason@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Shaohua Li <shli@kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Pull DMA mapping update from Marek Szyprowski:
 "This contains an addition of Device Tree support for reserved memory
  regions (Contiguous Memory Allocator is one of the drivers for it) and
  changes required by the KVM extensions for PowerPC architectue"

* 'for-v3.12' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping:
  ARM: init: add support for reserved memory defined by device tree
  drivers: of: add initialization code for dma reserved memory
  drivers: of: add function to scan fdt nodes given by path
  drivers: dma-contiguous: clean source code and prepare for device tree

Return directly if memory allocation fails. There is no need
of dma_free_coherent().
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Saeed Bishara <saeed@marvell.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Pull virtio update from Rusty Russell:
 "More console fixes; these are the theoretical ones which didn't get
  CC:stable.  But for that reason, I did a merge with master partway
  through to avoid an unnecessary conflict.

  Also: a fun lguest bug turns out if you don't clear the TF flag when
  trapping Bad Things happen to the guest kernel as the stack
  overflows..."

* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  virtio_pci: pm: Use CONFIG_PM_SLEEP instead of CONFIG_PM
  lguest: fix GPF in guest when using gdb.
  lguest: fix guest kernel stack overflow when TF bit set.
  lguest: fix BUG_ON() in invalid guest page table.
  virtio: console: prevent use-after-free of port name in port unplug
  virtio: console: cleanup an error message
  virtio: console: fix locking around send_sigio_to_port()
  virtio: console: add locking in port unplug path
  virtio: console: add locks around buffer removal in port unplug path
  tools/lguest: offer VIRTIO_F_ANY_LAYOUT for net device.
  virtio tools: add .gitignore
  lguest: Point to the right directory for the lguest launcher

Pull VFIO update from Alex Williamson:
 "VFIO updates include safer default file flags for VFIO device fds, an
  external user interface exported to allow other modules to hold
  references to VFIO groups, a fix to test for extended config space on
  PCIe and PCI-x, and new hot reset interfaces for PCI devices which
  allows the user to do PCI bus/slot resets when all of the devices
  affected by the reset are owned by the user.

  For this last feature, the PCI bus reset interface, I depend on
  changes already merged from Bjorn's PCI pull request.  I therefore
  merged my tree up to commit cb3e4330, which I think was the correct
  action, but as Stephen Rothwell noted, I failed to provide a commit
  message indicating why the merge was required.  Sorry for that.
  Thanks, Alex"

* tag 'vfio-v3.12-rc0' of git://github.com/awilliam/linux-vfio:
  vfio: fix documentation
  vfio-pci: PCI hot reset interface
  vfio-pci: Test for extended config space
  vfio-pci: Use fdget() rather than eventfd_fget()
  vfio: Add O_CLOEXEC flag to vfio device fd
  vfio: use get_unused_fd_flags(0) instead of get_unused_fd()
  vfio: add external user support

Pull NFS client updates from Trond Myklebust:
 "Highlights include:

   - Fix NFSv4 recovery so that it doesn't recover lost locks in cases
     such as lease loss due to a network partition, where doing so may
     result in data corruption.  Add a kernel parameter to control
     choice of legacy behaviour or not.
   - Performance improvements when 2 processes are writing to the same
     file.
   - Flush data to disk when an RPCSEC_GSS session timeout is imminent.
   - Implement NFSv4.1 SP4_MACH_CRED state protection to prevent other
     NFS clients from being able to manipulate our lease and file
     locking state.
   - Allow sharing of RPCSEC_GSS caches between different rpc clients.
   - Fix the broken NFSv4 security auto-negotiation between client and
     server.
   - Fix rmdir() to wait for outstanding sillyrename unlinks to complete
   - Add a tracepoint framework for debugging NFSv4 state recovery
     issues.
   - Add tracing to the generic NFS layer.
   - Add tracing for the SUNRPC socket connection state.
   - Clean up the rpc_pipefs mount/umount event management.
   - Merge more patches from Chuck in preparation for NFSv4 migration
     support"

* tag 'nfs-for-3.12-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (107 commits)
  NFSv4: use mach cred for SECINFO_NO_NAME w/ integrity
  NFS: nfs_compare_super shouldn't check the auth flavour unless 'sec=' was set
  NFSv4: Allow security autonegotiation for submounts
  NFSv4: Disallow security negotiation for lookups when 'sec=' is specified
  NFSv4: Fix security auto-negotiation
  NFS: Clean up nfs_parse_security_flavors()
  NFS: Clean up the auth flavour array mess
  NFSv4.1 Use MDS auth flavor for data server connection
  NFS: Don't check lock owner compatability unless file is locked (part 2)
  NFS: Don't check lock owner compatibility in writes unless file is locked
  nfs4: Map NFS4ERR_WRONG_CRED to EPERM
  nfs4.1: Add SP4_MACH_CRED write and commit support
  nfs4.1: Add SP4_MACH_CRED stateid support
  nfs4.1: Add SP4_MACH_CRED secinfo support
  nfs4.1: Add SP4_MACH_CRED cleanup support
  nfs4.1: Add state protection handler
  nfs4.1: Minimal SP4_MACH_CRED implementation
  SUNRPC: Replace pointer values with task->tk_pid and rpc_clnt->cl_clid
  SUNRPC: Add an identifier for struct rpc_clnt
  SUNRPC: Ensure rpc_task->tk_pid is available for tracepoints
  ...

Pull fuse bugfixes from Miklos Szeredi:
 "Just a bunch of bugfixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: use list_for_each_entry() for list traversing
  fuse: readdir: check for slash in names
  fuse: hotfix truncate_pagecache() issue
  fuse: invalidate inode attributes on xattr modification
  fuse: postpone end_page_writeback() in fuse_writepage_locked()

Pull GFS2 updates from Steven Whitehouse:
 "This is possibly the smallest ever set of GFS2 patches for a merge
  window.  Also, most of them are bug fixes this time.

  Two of my three patches (moving gfs2_sync_meta and merging the two
  writepage implementations) are clean ups with the third (taking the
  glock ref in examine_bucket) being a fix for a difficult to hit race
  condition.

  The removal of an unused memory barrier is a clean up from Bob
  Peterson, and the "spectator" relates to a rarely used mount option.
  Ben Marzinski's patch fixes a corner case where the incorrect inode
  flags were being set, resulting in incorrect behaviour on fsync"

* tag 'gfs2-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw:
  GFS2: dirty inode correctly in gfs2_write_end
  GFS2: Don't flag consistency error if first mounter is a spectator
  GFS2: Remove unnecessary memory barrier
  GFS2: Merge ordered and writeback writepage
  GFS2: Take glock reference in examine_bucket()
  GFS2: Move gfs2_sync_meta to lops.c

Pull ceph updates from Sage Weil:
 "This includes both the first pile of Ceph patches (which I sent to
  torvalds@vger, sigh) and a few new patches that add support for
  fscache for Ceph.  That includes a few fscache core fixes that David
  Howells asked go through the Ceph tree.  (Thanks go to Milosz Tanski
  for putting this feature together)

  This first batch of patches (included here) had (has) several
  important RBD bug fixes, hole punch support, several different
  cleanups in the page cache interactions, improvements in the truncate
  code (new truncate mutex to avoid shenanigans with i_mutex), and a
  series of fixes in the synchronous striping read/write code.

  On top of that is a random collection of small fixes all across the
  tree (error code checks and error path cleanup, obsolete wq flags,
  etc)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (43 commits)
  ceph: use d_invalidate() to invalidate aliases
  ceph: remove ceph_lookup_inode()
  ceph: trivial buildbot warnings fix
  ceph: Do not do invalidate if the filesystem is mounted nofsc
  ceph: page still marked private_2
  ceph: ceph_readpage_to_fscache didn't check if marked
  ceph: clean PgPrivate2 on returning from readpages
  ceph: use fscache as a local presisent cache
  fscache: Netfs function for cleanup post readpages
  FS-Cache: Fix heading in documentation
  CacheFiles: Implement interface to check cache consistency
  FS-Cache: Add interface to check consistency of a cached object
  rbd: fix null dereference in dout
  rbd: fix buffer size for writes to images with snapshots
  libceph: use pg_num_mask instead of pgp_num_mask for pg.seed calc
  rbd: fix I/O error propagation for reads
  ceph: use vfs __set_page_dirty_nobuffers interface instead of doing it inside filesystem
  ceph: allow sync_read/write return partial successed size of read/write.
  ceph: fix bugs about handling short-read for sync read mode.
  ceph: remove useless variable revoked_rdcache
  ...

Pull metag architecture changes from James Hogan:
 - Device tree updates for TZ1090 GPIO drivers merged via GPIO tree.
 - Add driver for ImgTec PDC irqchip as found in TZ1090 SoC.
 - Add linux-metag mailing list to MAINTAINERS file.

* tag 'metag-for-v3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/metag:
  irq-imgpdc: add ImgTec PDC irqchip driver
  MAINTAINERS: add linux-metag mailing list
  metag: tz1090: instantiate gpio-tz1090-pdc
  metag: tz1090: select and instantiate gpio-tz1090
  metag: tz1090: select and instantiate irq-imgpdc

Pull ARC changes from Vineet Gupta:

 - ARC MM changes:
    - preparation for MMUv4 (accomodate new PTE bits, new cmds)
    - Rework the ASID allocation algorithm to remove asid-mm reverse map
 - Boilerplate code consolidation in Exception Handlers
 - Disable FRAME_POINTER for ARC
 - Unaligned Access Emulation for Big-Endian from Noam
 - Bunch of fixes (udelay, missing accessors) from Mischa

* tag 'arc-v3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: fix new Section mismatches in build (post __cpuinit cleanup)
  Kconfig.debug: Add FRAME_POINTER anti-dependency for ARC
  ARC: Fix __udelay calculation
  ARC: remove console_verbose() from setup_arch()
  ARC: Add read*_relaxed to asm/io.h
  ARC: Handle un-aligned user space access in BE.
  ARC: [ASID] Track ASID allocation cycles/generations
  ARC: [ASID] activate_mm() == switch_mm()
  ARC: [ASID] get_new_mmu_context() to conditionally allocate new ASID
  ARC: [ASID] Refactor the TLB paranoid debug code
  ARC: [ASID] Remove legacy/unused debug code
  ARC: No need to flush the TLB in early boot
  ARC: MMUv4 preps/3 - Abstract out TLB Insert/Delete
  ARC: MMUv4 preps/2 - Reshuffle PTE bits
  ARC: MMUv4 preps/1 - Fold PTE K/U access flags
  ARC: Code cosmetics (Nothing semantical)
  ARC: Entry Handler tweaks: Optimize away redundant IRQ_DISABLE_SAVE
  ARC: Exception Handlers Code consolidation
  ARC: Add some .gitignore entries

Pull m68knommu fixes from Greg Ungerer:
 "Just a small collection of cleanups and fixes this time, no big
  changes.  The most interresting are to make the m68k and m68knommu
  consistently use CONFIG_IOMAP, clean out some unused board config
  options and flush the cache on signal stack creation"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu:
  m68k: remove 16 unused boards in Kconfig.machine
  m68k: define 'VM_DATA_DEFAULT_FLAGS' no matter whether has 'NOMMU' or not
  m68knommu: user generic iomap to support ioread*/iowrite*
  m68k/coldfire: flush cache when creating the signal stack frame
  m68knommu: Mark functions only called from setup_arch() __init

Pull UML updates from Richard Weinberger:
 "This pile contains mostly fixes and improvements for issues identified
  by Richard W M Jones while adding UML as backend to libguestfs"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: Add irq chip um/mask handlers
  um: prctl: Do not include linux/ptrace.h
  um: Run UML in it's own session.
  um: Cleanup SIGTERM handling
  um: ubd: Introduce submit_request()
  um: ubd: Add REQ_FLUSH suppport
  um: Implement probe_kernel_read()
  um: hostfs: Fix writeback

When reconnecting to automounts at startup an autofs ioctl is used
to find the device and inode of existing mounts so they can be used
to open a file descriptor of possibly covered mounts.

At this time the the caller might not yet "own" the mount so it can
trigger calling ->d_automount(). This causes automount to hang when
trying to reconnect to direct or offset mount types.

Consequently kern_path() can't be used but kern_path_mountpoint() can be.
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

This is the fix that the last two commits indirectly led up to - making
sure that we don't call dput() in a bad context on the dentries we've
looked up in RCU mode after the sequence count validation fails.

This basically expands d_rcu_to_refcount() into the callers, and then
fixes the callers to delay the dput() in the failure case until _after_
we've dropped all locks and are no longer in an RCU-locked region.

The case of 'complete_walk()' was trivial, since its failure case did
the unlock_rcu_walk() directly after the call to d_rcu_to_refcount(),
and as such that is just a pure expansion of the function with a trivial
movement of the resulting dput() to after 'unlock_rcu_walk()'.

In contrast, the unlazy_walk() case was much more complicated, because
not only does convert two different dentries from RCU to be reference
counted, but it used to not call unlock_rcu_walk() at all, and instead
just returned an error and let the caller clean everything up in
"terminate_walk()".

Happily, one of the dentries in question (called "parent" inside
unlazy_walk()) is the dentry of "nd->path", which terminate_walk() wants
a refcount to anyway for the non-RCU case.

So what the new and improved unlazy_walk() does is to first turn that
dentry into a refcounted one, and once that is set up, the error cases
can continue to use the terminate_walk() helper for cleanup, but for the
non-RCU case.  Which makes it possible to drop out of RCU mode if we
actually hit the sequence number failure case.
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The virtio_pci_freeze/restore are defined under CONFIG_PM but is used
by SET_SYSTEM_SLEEP_PM_OPS macro, which is defined under
CONFIG_PM_SLEEP. So if CONFIG_PM_SLEEP is not cofigured but
CONFIG_PM_RUNTIME is, the following warning message appeared:

drivers/virtio/virtio_pci.c:770:12: warning: ‘virtio_pci_freeze’ defined but not used [-Wunused-function]
 static int virtio_pci_freeze(struct device *dev)
            ^
drivers/virtio/virtio_pci.c:790:12: warning: ‘virtio_pci_restore’ defined but not used [-Wunused-function]
 static int virtio_pci_restore(struct device *dev)
            ^
Fix it by changing CONFIG_PM to CONFIG_PM_SLEEP.
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

... and move the extern from linux/namei.h to fs/internal.h,
along with that of vfs_path_lookup().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

... and massage it a bit to reduce nesting
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>