PAPR specifies that DTL buffers can not cross AMS environments (aka CMO
in the PAPR) and can not cross a memory entitlement granule boundary
(4k). This is found in section 14.11.3.2 H_REGISTER_VPA of the PAPR.
kmalloc does not guarantee an alignment of the allocation, though,
beyond 8 bytes (at least in my understanding). Create a special kmem
cache for DTL buffers with the alignment requirement.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Recent commit b987812b caused
a compile failure on UP because a considerably large block
of the file was included within CONFIG_SMP, hence making a stub
function not exposed on UP builds when it needed to be.

Relocate the stub to the #else /* ! CONFIG_SMP */ section
and also annotate the relevant else/endif so that nobody
else falls into the same trap I did.
Reported-by: Michael Guntsche <mike@it-loops.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

* 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
  i2c-algo-bit: Call pre/post_xfer for bit_test
  i2c: Improve deprecation warnings

Merge branch 's5p-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung

* 's5p-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung:
  ARM: SAMSUNG: Fix warning 's3c_pm_show_resume_irqs' defined but not used
  ARM: SAMSUNG: Fix build failure in PM CRC check code
  ARM: S5P: Remove unused s3c_pm_check_resume_pin

Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Following commit 091738a2 ("genirq: Remove real old transition
functions") we removed an automatic conversion of no_irq_chip to
dummy_irq_chip.  This change needs to be propagated back into the alpha
backend.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This is a new warning in gcc 4.6.  Several of these variables are
used within #if 0 code, which probably ought to be removed.  Most
of the changes are legitimate cleanups.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There are outstanding gcc 4.6 warnings that need to be cleaned up
in the subdirectory.  No sense forcing the issue immediately.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

While checking unregister_filesystem for saftey vs extra calls for
"ext4: register ext2 and ext3 alias after ext4" I realized that
the synchronize_rcu() was called on the error path but not on
the success path.

Cc: stable (2.6.38)
Signed-off-by: Milton Miller <miltonm@bga.com>
[ This probably won't really make a difference since commit d863b50a
  ("vfs: call rcu_barrier after ->kill_sb()"), but it's the right thing
  to do.  - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Apparently some distros set i2c-algo-bit.bit_test to 1 by
default.  In some cases this causes i2c_bit_add_bus
to fail and prevents the i2c bus from being added.  In the
radeon case, we fail to add the ddc i2c buses which prevents
the driver from being able to detect attached monitors.
The i2c bus works fine even if bit_test fails.  This is likely
due to gpio switching that is required and handled in the
pre/post_xfer hooks, so call the pre/post_xfer hooks in the
bit test as well.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=36221Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: stable@kernel.org [.38 down to .34]

When warning on the use of deprecated i2c_driver methods
attach_adapter and detach_adapter, mention the name of the driver
which needs to be updated.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  block: make unplug timer trace event correspond to the schedule() unplug
  block: let io_schedule() flush the plug inline

* 'usb-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6: (43 commits)
  Revert "USB: isp1760-hcd: move imask clear after pending work is done"
  xHCI: Implement AMD PLL quirk
  xhci: Tell USB core both roothubs lost power.
  usbcore: Bug fix: system can't suspend with USB3.0 device connected to USB3.0 hub
  USB: Fix unplug of device with active streams
  USB: xhci - also free streams when resetting devices
  xhci: Fix NULL pointer deref in handle_port_status()
  USB: xhci - fix math in xhci_get_endpoint_interval()
  USB: xhci: simplify logic of skipping missed isoc TDs
  USB: xhci - remove excessive 'inline' markings
  USB: xhci: unsigned char never equals -1
  USB: xhci - fix unsafe macro definitions
  USB: fix formatting of SuperSpeed endpoints in /proc/bus/usb/devices
  USB: isp1760-hcd: move imask clear after pending work is done
  USB: fsl_qe_udc: send ZLP when zero flag and length % maxpacket == 0
  usb: qcserial add missing errorpath kfrees
  usb: qcserial avoid pointing to freed memory
  usb: Fix qcserial memory leak on rmmod
  USB: ftdi_sio: add ids for Hameg HO720 and HO730
  USB: option: Added support for Samsung GT-B3730/GT-B3710 LTE USB modem.
  ...

Merge branches 'core-fixes-for-linus', 'perf-fixes-for-linus', 'sched-fixes-for-linus', 'timer-fixes-for-linus' and 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  futex: Set FLAGS_HAS_TIMEOUT during futex_wait restart setup

* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf_event: Fix cgrp event scheduling bug in perf_enable_on_exec()
  perf: Fix a build error with some GCC versions

* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: Fix erroneous all_pinned logic
  sched: Fix sched-domain avg_load calculation

* 'timer-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  RTC: rtc-mrst: follow on to the change of rtc_device_register()
  RTC: add missing "return 0" in new alarm func for rtc-bfin.c
  RTC: Fix s3c compile error due to missing s3c_rtc_setpie
  RTC: Fix early irqs caused by calling rtc_set_alarm too early

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, amd: Disable GartTlbWlkErr when BIOS forgets it
  x86, NUMA: Fix fakenuma boot failure
  x86/mrst: Fix boot crash caused by incorrect pin to irq mapping
  x86/ce4100: Add reg property to bridges

It's a pretty close match to what we had before - the timer triggering
would mean that nobody unplugged the plug in due time, in the new
scheme this matches very closely what the schedule() unplug now is.
It's essentially the difference between an explicit unplug (IO unplug)
or an implicit unplug (timer unplug, we scheduled with pending IO
queued).
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

Linus correctly observes that the most important dispatch cases
are now done from kblockd, this isn't ideal for latency reasons.
The original reason for switching dispatches out-of-line was to
avoid too deep a stack, so by _only_ letting the "accidental"
flush directly in schedule() be guarded by offload to kblockd,
we should be able to get the best of both worlds.

So add a blk_schedule_flush_plug() that offloads to kblockd,
and only use that from the schedule() path.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  net/9p: nwname should be an unsigned int
  9p: Fix sparse error
  fs/9p: Fix error reported by coccicheck
  9p: revert tsyncfs related changes
  fs/9p: Use write_inode for data sync on server
  fs/9p: Fix revalidate to return correct value

* 'for-linus' of git://android.git.kernel.org/kernel/tegra:
  arm: tegra: fix error check in tegra2_clocks.c
  ARM: tegra: gpio: Fix unused variable warnings

* 'fixes' of master.kernel.org:/home/rmk/linux-2.6-arm:
  ARM: 6879/1: fix personality test wrt usage of domain handlers
  ARM: 6878/1: fix personality flag propagation across an exec
  ARM: 6877/1: the ADDR_NO_RANDOMIZE personality flag should be honored with mmap()
  ARM: 6876/1: Kconfig.debug: Remove unused CONFIG_DEBUG_ERRORS
  ARM: pxa: convert incorrect IRQ_TO_IRQ() to irq_to_gpio()
  ARM: mmp: align NR_BUILTIN_GPIO with gpio interrupt number
  ARM: pxa: align NR_BUILTIN_GPIO with GPIO interrupt number
  ARM: pxa: always clear LPM bits for PXA168 MFPR
  pcmcia: limit pxa2xx_trizeps4 subdriver to trizeps4 platform
  pcmcia: limit pxa2xx_balloon3 subdriver to balloon3 platform
  ARM: pxafb: Fix access to nonexistent member of pxafb_info
  ARM: 6872/1: arch:common:Makefile Remove unused config in the Makefile.
  ARM: 6868/1: Preserve the VFP state during fork
  ARM: 6867/1: Introduce THREAD_NOTIFY_COPY for copy_thread() hooks
  ARM: 6866/1: Do not restrict HIGHPTE to !OUTER_CACHE
  ARM: 6865/1: perf: ensure pass through zero is counted on overflow
  ARM: 6864/1: hw_breakpoint: clear DBGVCR out of reset
  ARM: Only allow PM_SLEEP with CPUs which support suspend
  ARM: Make consolidated PM sleep code depend on PM_SLEEP

This patch disables GartTlbWlk errors on AMD Fam10h CPUs if
the BIOS forgets to do is (or is just too old). Letting
these errors enabled can cause a sync-flood on the CPU
causing a reboot.

The AMD BKDG recommends disabling GART TLB Wlk Error completely.

This patch is the fix for

	https://bugzilla.kernel.org/show_bug.cgi?id=33012

on my machine.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Link: http://lkml.kernel.org/r/20110415131152.GJ18463@8bytes.orgTested-by: Alexandre Demers <alexandre.f.demers@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

During RCU walk in path_lookupat and path_openat, the rcu lookup
frequently failed if looking up an absolute path, because when root
directory was looked up, seq number was not properly set in nameidata.

We dropped out of RCU walk in nameidata_drop_rcu due to mismatch in
directory entry's seq number.  We reverted to slow path walk that need
to take references.

With the following patch, I saw a 50% increase in an exim mail server
benchmark throughput on a 4-socket Nehalem-EX system.
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Cc: stable@kernel.org (v2.6.38)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Harsh Prateek Bora <harsh@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric VAn Hensbergen <ericvh@gmail.com>

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

Now that we use write_inode to flush server
cache related to fid, we don't need tsyncfs either fort dotl or dotu
protocols. For dotu this helps to do a more efficient server flush.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

revalidate should return > 0 on success. Also return 0 on ENOENT
to force do_revalidate to return NULL dentry;
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

Currently, numa=fake boot parameter is broken. If it's used,
kernel may panic due to devide by zero error depending on CPU
configuration

Call Trace:
 [<ffffffff8104ad4c>] find_busiest_group+0x38c/0xd30
 [<ffffffff81086aff>] ? local_clock+0x6f/0x80
 [<ffffffff81050533>] load_balance+0xa3/0x600
 [<ffffffff81050f53>] idle_balance+0xf3/0x180
 [<ffffffff81550092>] schedule+0x722/0x7d0
 [<ffffffff81550538>] ? wait_for_common+0x128/0x190
 [<ffffffff81550a65>] schedule_timeout+0x265/0x320
 [<ffffffff81095815>] ? lock_release_holdtime+0x35/0x1a0
 [<ffffffff81550538>] ? wait_for_common+0x128/0x190
 [<ffffffff8109bb6c>] ? __lock_release+0x9c/0x1d0
 [<ffffffff815534e0>] ? _raw_spin_unlock_irq+0x30/0x40
 [<ffffffff815534e0>] ? _raw_spin_unlock_irq+0x30/0x40
 [<ffffffff81550540>] wait_for_common+0x130/0x190
 [<ffffffff81051920>] ? try_to_wake_up+0x510/0x510
 [<ffffffff8155067d>] wait_for_completion+0x1d/0x20
 [<ffffffff8107f36c>] kthread_create_on_node+0xac/0x150
 [<ffffffff81077bb0>] ? process_scheduled_works+0x40/0x40
 [<ffffffff8155045f>] ? wait_for_common+0x4f/0x190
 [<ffffffff8107a283>] __alloc_workqueue_key+0x1a3/0x590
 [<ffffffff81e0cce2>] cpuset_init_smp+0x6b/0x7b
 [<ffffffff81df3d07>] kernel_init+0xc3/0x182
 [<ffffffff8155d5e4>] kernel_thread_helper+0x4/0x10
 [<ffffffff81553cd4>] ? retint_restore_args+0x13/0x13
 [<ffffffff81df3c44>] ? start_kernel+0x400/0x400
 [<ffffffff8155d5e0>] ? gs_change+0x13/0x13

The divede by zero is caused by the following line,
group->cpu_power==0:

 kernel/sched_fair.c::update_sg_lb_stats()
        /* Adjust by relative CPU power of the group */
        sgs->avg_load = (sgs->group_load * SCHED_LOAD_SCALE) / group->cpu_power;

This regression was caused by commit e23bba60 ("x86-64, NUMA: Unify
emulated distance mapping") because it changes cpu -> node
mapping in the process of dropping fake_physnodes().

  old) all cpus are assinged node 0
  now) cpus are assigned round robin
       (the logic is implemented by numa_init_array())

  Note: The change in behavior only happens if the system doesn't
        have neither ACPI SRAT table nor AMD northbridge NUMA
	information.

Round robin assignment doesn't work because init_numa_sched_groups_power()
assumes all logical cpus in the same physical cpu share the same node
(then it only accounts for group_first_cpu()), and the simple round robin
breaks the above assumption.

Thus, this patch implements a reassignment of node-ids if buggy firmware
or numa emulation makes wrong cpu node map. Tt enforce all logical cpus
in the same physical cpu share the same node.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Shaohui Zheng <shaohui.zheng@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/20110415203928.1303.A69D9226@jp.fujitsu.comSigned-off-by: Ingo Molnar <mingo@elte.hu>

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  block: only force kblockd unplugging from the schedule() path
  block: cleanup the block plug helper functions
  block, blk-sysfs: Use the variable directly instead of a function call
  block: move queue run on unplug to kblockd
  block: kill queue_sync_plugs()
  block: readd plug trace event
  block: add callback function for unplug notification
  block: add comment on why we save and disable interrupts in flush_plug_list()
  block: fixup block IO unplug trace call
  block: remove block_unplug_timer() trace point
  block: splice plug list to local context

* 'linux-next' of git://git.infradead.org/ubifs-2.6:
  UBIFS: fix compilation warnings when compiling with gcc 4.5
  UBIFS: fix oops when R/O file-system is fsync'ed

The FLAGS_HAS_TIMEOUT flag was not getting set, causing the restart_block to
restart futex_wait() without a timeout after a signal.

Commit b41277dc in 2.6.38 introduced the regression by accidentally
removing the the FLAGS_HAS_TIMEOUT assignment from futex_wait() during the setup
of the restart block. Restore the originaly behavior.

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=32922Reported-by: Tim Smith <tsmith201104@yahoo.com>
Reported-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/%3Cdaac0eb3af607f72b9a4d3126b2ba8fb5ed3b883.1302820917.git.dvhart%40linux.intel.com%3ESigned-off-by: Thomas Gleixner <tglx@linutronix.de>

The case we should be verifying when updating the dentry name is that
the _parent_ inode (the directory) semaphore is held, not the semaphore
for the dentry itself.  It's the directory locking that rename and
readdir() etc all care about.

The comment just above even says so - but then the BUG_ON() still
checked the dentry inode itself.

Very few people noticed, because this helper function really isn't used
for very much, so you had to be using ncpfs to ever hit it.

I think I should just remove the BUG_ON (the function really has just
one user), but let's run with it fixed for a while before getting rid of
it entirely.
Reported-and-tested-by: Bongani Hlope <bonganih@bankservafrica.com>
Reported-and-tested-by: Bernd Feige <bernd.feige@uniklinik-freiburg.de>
Cc: Petr Vandrovec <petr@vandrovec.name>,
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

For the explicit unplugging, we'd prefer to kick things off
immediately and not pay the penalty of the latency to switch
to kblockd. So let blk_finish_plug() do the run inline, while
the implicit-on-schedule-out unplug will punt to kblockd.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

It's a bit of a mess currently. task->plug is being cleared
and reset in __blk_finish_plug(), and blk_finish_plug() is
testing for a NULL plug which cannot happen even from schedule()
anymore since it uses blk_needs_flush_plug() to determine
whether to call into this function at all.

So get rid of some of the cruft.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/vapier/blackfin:
  Blackfin: SMP: fix cache flush loop
  Blackfin: time-ts: ack gptimer sooner to avoid missing short ints
  Blackfin: gptimers: fix thinko when disabling timers
  Blackfin: SMP: make all barriers handle cache issues

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  libceph: fix linger request requeueing

The conventional format for boolean attributes in sysfs is numeric ("0" or
"1" followed by new-line).  Any boolean attribute can then be read and
written using a generic function.  Using the strings "yes [no]", "[yes]
no" (read), "yes" and "no" (write) will frustrate this.

[akpm@linux-foundation.org: use kstrtoul()]
[akpm@linux-foundation.org: test_bit() doesn't return 1/0, per Neil]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Tested-by: David Rientjes <rientjes@google.com>
Cc: NeilBrown <neilb@suse.de>
Cc: <stable@kernel.org> 	[2.6.38.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

On no-mmu arch, there is a memleak during shmem test.  The cause of this
memleak is ramfs_nommu_expand_for_mapping() added page refcount to 2
which makes iput() can't free that pages.

The simple test file is like this:

  int main(void)
  {
	int i;
	key_t k = ftok("/etc", 42);

	for ( i=0; i<100; ++i) {
		int id = shmget(k, 10000, 0644|IPC_CREAT);
		if (id == -1) {
			printf("shmget error\n");
		}
		if(shmctl(id, IPC_RMID, NULL ) == -1) {
			printf("shm  rm error\n");
			return -1;
		}
	}
	printf("run ok...\n");
	return 0;
  }

And the result:

  root:/> free
               total         used         free       shared      buffers
  Mem:         60320        17912        42408            0            0
  -/+ buffers:              17912        42408
  root:/> shmem
  run ok...
  root:/> free
               total         used         free       shared      buffers
  Mem:         60320        19096        41224            0            0
  -/+ buffers:              19096        41224
  root:/> shmem
  run ok...
  root:/> free
               total         used         free       shared      buffers
  Mem:         60320        20296        40024            0            0
  -/+ buffers:              20296        40024
  ...

After this patch the test result is:(no memleak anymore)

  root:/> free
               total         used         free       shared      buffers
  Mem:         60320        16668        43652            0            0
  -/+ buffers:              16668        43652
  root:/> shmem
  run ok...
  root:/> free
               total         used         free       shared      buffers
  Mem:         60320        16668        43652            0            0
  -/+ buffers:              16668        43652
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 8a5ec0ba "Lockless (and preemptless) fastpaths for slub" makes use
of this_cpu_cmpxchg_double() which needs this_cpu_cmpxchg16b_emu() on
x86_64.  Implementing cmpxchg16b emulation for UML would introduce too
much complexity.  So just disable it.
Signed-off-by: Richard Weinberger <richard@nod.at>
Reported-by: Sergei Trofimovich <slyich@gmail.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>