There is a loophole between Xen's current implementation of
pv-spinlocks and the scheduler. This was triggerable through
a testcase until v3.6 changed the TLB flushing code. The
problem potentially is still there just not observable in the
same way.

What could happen was (is):

1. CPU n tries to schedule task x away and goes into a slow
   wait for the runq lock of CPU n-# (must be one with a lower
   number).
2. CPU n-#, while processing softirqs, tries to balance domains
   and goes into a slow wait for its own runq lock (for updating
   some records). Since this is a spin_lock_irqsave in softirq
   context, interrupts will be re-enabled for the duration of
   the poll_irq hypercall used by Xen.
3. Before the runq lock of CPU n-# is unlocked, CPU n-1 receives
   an interrupt (e.g. endio) and when processing the interrupt,
   tries to wake up task x. But that is in schedule and still
   on_cpu, so try_to_wake_up goes into a tight loop.
4. The runq lock of CPU n-# gets unlocked, but the message only
   gets sent to the first waiter, which is CPU n-# and that is
   busily stuck.
5. CPU n-# never returns from the nested interruption to take and
   release the lock because the scheduler uses a busy wait.
   And CPU n never finishes the task migration because the unlock
   notification only went to CPU n-#.

To avoid this and since the unlocking code has no real sense of
which waiter is best suited to grab the lock, just send the IPI
to all of them. This causes the waiters to return from the hyper-
call (those not interrupted at least) and do active spinlocking.

BugLink: http://bugs.launchpad.net/bugs/1011792Acked-by: Jan Beulich <JBeulich@suse.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Cc: stable@vger.kernel.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

ioremap can't be used to map ring pages on ARM because it uses device
memory caching attributes (MT_DEVICE*).

Introduce a Xen specific abstraction to map ring pages, called
xen_remap, that is defined as ioremap on x86 (no behavioral changes).
On ARM it explicitly calls __arm_ioremap with the right caching
attributes: MT_MEMORY.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

CC: stable@vger.kernel.org
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The evtchn device has been moved to /dev/xen. Also change log level to
KERN_ERR as other xen drivers.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Seems that it got lost.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

To avoid compile issue and it's meanigfull only under CONFIG_XEN_DOM0.

In file included from linux/arch/x86/xen/enlighten.c:47:0:
	linux/include/xen/acpi.h:75:76: error: unknown type name ‘acpi_handle’
make[3]: *** [arch/x86/xen/enlighten.o] Error 1
Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
[v1: Fixed spelling mistakes]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This patch implement real Xen ACPI cpu hotplug driver as module.
When loaded, it replaces Xen stub driver.

For booting existed cpus, the driver enumerates them.
For hotadded cpus, which added at runtime and notify OS via
device or container event, the driver is invoked to add them,
parsing cpu information, hypercalling to Xen hypervisor to add
them, and finally setting up new /sys interface for them.
Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

So that it could be reused by Xen CPU hotplug logic.
Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Add Xen stub driver for CPU hotplug, early occupy to block native,
will be replaced later by real Xen processor driver module.
Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This patch implements real Xen acpi memory hotplug driver as module.
When loaded, it replaces Xen stub driver.

When an acpi memory device hotadd event occurs, it notifies OS and
invokes notification callback, adding related memory device and parsing
memory information, finally hypercall to xen hypervisor to add memory.
Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This patch create a file (xen-stub.c) for Xen stub drivers.
Xen stub drivers are used to reserve space for Xen drivers, i.e.
memory hotplug and cpu hotplug, and to block native drivers loaded,
so that real Xen drivers can be modular and loaded on demand.

This patch is specific for Xen memory hotplug (other Xen logic
can add stub drivers on their own). The xen stub driver will
occupied earlier via subsys_initcall (than native memory hotplug
driver via module_init and so blocking native). Later real Xen
memory hotplug logic will unregister the stub driver and register
itself to take effect on demand.
Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Allows for more fine grained error reporting. Only used by PVH and
ARM both of which are marked EXPERIMENTAL precisely because the ABI
is not yet stable
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
[v1: Rebased without PVH patches]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The PV and PVH code CPU init code share some functionality. The
PVH code ("xen/pvh: Extend vcpu_guest_context, p2m, event, and XenBus")
sets some of these up, but not all. To make it easier to read, this
patch removes the PV specific out of the generic way.

No functional change - just code movement.
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
[v2: Fixed compile errors noticed by Fengguang Wu build system]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Pull btrfs fixes from Chris Mason:
 "It turns out that we had two crc bugs when running fsx-linux in a
  loop.  Many thanks to Josef, Miao Xie, and Dave Sterba for nailing it
  all down.  Miao also has a new OOM fix in this v2 pull as well.

  Ilya fixed a regression Liu Bo found in the balance ioctls for pausing
  and resuming a running balance across drives.

  Josef's orphan truncate patch fixes an obscure corruption we'd see
  during xfstests.

  Arne's patches address problems with subvolume quotas.  If the user
  destroys quota groups incorrectly the FS will refuse to mount.

  The rest are smaller fixes and plugs for memory leaks."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (30 commits)
  Btrfs: fix repeated delalloc work allocation
  Btrfs: fix wrong max device number for single profile
  Btrfs: fix missed transaction->aborted check
  Btrfs: Add ACCESS_ONCE() to transaction->abort accesses
  Btrfs: put csums on the right ordered extent
  Btrfs: use right range to find checksum for compressed extents
  Btrfs: fix panic when recovering tree log
  Btrfs: do not allow logged extents to be merged or removed
  Btrfs: fix a regression in balance usage filter
  Btrfs: prevent qgroup destroy when there are still relations
  Btrfs: ignore orphan qgroup relations
  Btrfs: reorder locks and sanity checks in btrfs_ioctl_defrag
  Btrfs: fix unlock order in btrfs_ioctl_rm_dev
  Btrfs: fix unlock order in btrfs_ioctl_resize
  Btrfs: fix "mutually exclusive op is running" error code
  Btrfs: bring back balance pause/resume logic
  btrfs: update timestamps on truncate()
  btrfs: fix btrfs_cont_expand() freeing IS_ERR em
  Btrfs: fix a bug when llseek for delalloc bytes behind prealloc extents
  Btrfs: fix off-by-one in lseek
  ...

Pull cifs fixes from Steve French:
 "Two small cifs fixes"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  fs/cifs/cifs_dfs_ref.c: fix potential memory leakage
  cifs: fix srcip_matches() for ipv6

Pull kvm fixlet from Marcelo Tosatti.

* git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: PPC: Emulate dcbf

Pull ARM fixes from Russell King:
 "A number of fixes:

  Patrik found a problem with preempt counting in the VFP assembly
  functions which can cause the preempt count to be upset.

  Nicolas fixed a problem with the parsing of the DT when it straddles a
  1MB boundary.

  Subhash Jadavani reported a problem with sparsemem and our highmem
  support for cache maintanence for DMA areas, and TI found a bug in
  their strongly ordered memory mapping type.

  Also, three fixes by way of Will Deacon's tree from Dave Martin for
  instruction compatibility and Marc Zyngier to fix hypervisor boot mode
  issues."

* 'fixes' of git://git.linaro.org/people/rmk/linux-arm:
  ARM: 7629/1: mm: Fix missing XN flag for for MT_MEMORY_SO
  ARM: DMA: Fix struct page iterator in dma_cache_maint() to work with sparsemem
  ARM: 7628/1: head.S: map one extra section for the ATAG/DTB area
  ARM: 7627/1: Predicate preempt logic on PREEMP_COUNT not PREEMPT alone
  ARM: virt: simplify __hyp_stub_install epilog
  ARM: virt: boot secondary CPUs through the right entry point
  ARM: virt: Avoid bx instruction for compatibility with <=ARMv4

Pull ARM SoC fixes from Olof Johansson:
 "Here's a long-pending fixes pull request for arm-soc (I didn't send
  one in the -rc4 cycle).

  The larger deltas are from:

   - A fixup of error paths in the mvsdio driver

   - Header file move for a driver that hadn't been properly converted
     to multiplatform on i.MX, which was causing build failures when
     included

   - Device tree updates for at91 dealing mostly with their new pinctrl
     setup merged in 3.8 and mistakes in those initial configs

  The rest are the normal mix of small fixes all over the place; sunxi,
  omap, imx, mvebu, etc, etc."

* tag 'fixes-for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (40 commits)
  mfd: vexpress-sysreg: Don't skip initialization on probe
  ARM: vexpress: Enable A7 cores in V2P-CA15_A7's Device Tree
  ARM: vexpress: extend the MPIDR range used for pen release check
  ARM: at91/dts: correct comment in at91sam9x5.dtsi for mii
  ARM: at91/at91_dt_defconfig: add at91sam9n12 SoC to DT defconfig
  ARM: at91/at91_dt_defconfig: remove memory specification to cmdline
  ARM: at91/dts: add macb mii pinctrl config for kizbox
  ARM: at91: rm9200: remake the BGA as default version
  ARM: at91: fix gpios on i2c-gpio for RM9200 DT
  ARM: at91/at91sam9x5 DTS: add SCK USART pins
  ARM: at91/at91sam9x5 DTS: correct wrong PIO BANK values on u(s)arts
  ARM: at91/at91-pinctrl documentation: fix typo and add some details
  ARM: kirkwood: fix missing #interrupt-cells property
  mmc: mvsdio: use devm_ API to simplify/correct error paths.
  clk: mvebu/clk-cpu.c: fix memory leakage
  ARM: OMAP2+: omap4-panda: add UART2 muxing for WiLink shared transport
  ARM: OMAP2+: DT node Timer iteration fix
  ARM: OMAP2+: Fix section warning for omap_init_ocp2scp()
  ARM: OMAP2+: fix build break for omapdrm
  ARM: OMAP2: Fix missing omap2xxx_clkt_vps_late_init function calls
  ...

Pull ACPI and power management fixes from Rafael Wysocki:

 - Two cpuidle initialization fixes from Konrad Rzeszutek Wilk.

 - cpufreq regression fixes for AMD processors from Borislav Petkov,
   Stefan Bader, and Matthew Garrett.

 - ACPI cpufreq fix from Thomas Schlichter.

 - cpufreq and devfreq fixes related to incorrect usage of operating
   performance points (OPP) framework and RCU from Nishanth Menon.

 - APEI workaround for incorrect BIOS information from Lans Zhang.

* tag 'pm+acpi-for-3.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: Add module aliases for acpi-cpufreq
  ACPI: Check MSR valid bit before using P-state frequencies
  PM / devfreq: exynos4_bus: honor RCU lock usage
  PM / devfreq: add locking documentation for recommended_opp
  cpufreq: cpufreq-cpu0: use RCU locks around usage of OPP
  cpufreq: OMAP: use RCU locks around usage of OPP
  ACPI, APEI: Fixup incorrect 64-bit access width firmware bug
  ACPI / processor: Get power info before updating the C-states
  powernow-k8: Add a kconfig dependency on acpi-cpufreq
  ACPI / cpuidle: Fix NULL pointer issues when cpuidle is disabled
  intel_idle: Don't register CPU notifier if we are not running.

Pull regmap fixes from Mark Brown:
 "One more oversight in the debugfs code was reported and fixed, plus a
  documentation fix."

* tag 'regmap-fix-3.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap:
  regmap: fix small typo in regmap_bulk_write comment
  regmap: debugfs: Fix seeking from the cache

Pull slave-dmaengine fixes from Vinod Koul:
 "A few fixes on slave dmanengine.  There are trivial fixes in imx-dma,
  tegra-dma & ioat driver"

* 'fixes' of git://git.infradead.org/users/vkoul/slave-dma:
  dma: tegra: implement flags parameters for cyclic transfer
  dmaengine: imx-dma: Disable use of hw_chain to fix sg_dma transfers.
  ioat: Fix DMA memory sync direction correct flag

Pill i2c fixes from Wolfram Sang:
 "Here are a few, typical driver fixes for the I2C subsystem"

* 'i2c-embedded/for-current' of git://git.pengutronix.de/git/wsa/linux:
  i2c-designware: add missing MODULE_LICENSE
  i2c: omap: fix draining irq handling
  i2c: omap: errata i462: fix incorrect ack for arbitration lost interrupt
  i2c: muxes: fix wrong use of sizeof(ptr)
  i2c: sirf: register i2c_client from dt child-nodes in probe entry
  i2c: mxs: Fix type of error code
  i2c: mxs: Fix misuse init_completion

btrfs_start_delalloc_inodes() locks the delalloc_inodes list, fetches the
first inode, unlocks the list, triggers btrfs_alloc_delalloc_work/
btrfs_queue_worker for this inode, and then it locks the list, checks the
head of the list again. But because we don't delete the first inode that it
deals with before, it will fetch the same inode. As a result, this function
allocates a huge amount of btrfs_delalloc_work structures, and OOM happens.

Fix this problem by splice this delalloc list.
Reported-by: Alex Lyakas <alex.btrfs@zadarastorage.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

The max device number of single profile is 1, not 0 (0 means 'as many as
possible'). Fix it.

Cc: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

First, though the current transaction->aborted check can stop the commit early
and avoid unnecessary operations, it is too early, and some transaction handles
don't end, those handles may set transaction->aborted after the check.

Second, when we commit the transaction, we will wake up some worker threads to
flush the space cache and inode cache. Those threads also allocate some transaction
handles and may set transaction->aborted if some serious error happens.

So we need more check for ->aborted when committing the transaction. Fix it.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

We may access and update transaction->aborted on the different CPUs without
lock, so we need ACCESS_ONCE() wrapper to prevent the compiler from creating
unsolicited accesses and make sure we can get the right value.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

I noticed a WARN_ON going off when adding csums because we were going over
the amount of csum bytes that should have been allowed for an ordered
extent.  This is a leftover from when we used to hold the csums privately
for direct io, but now we use the normal ordered sum stuff so we need to
make sure and check if we've moved on to another extent so that the csums
are added to the right extent.  Without this we could end up with csums for
bytenrs that don't have extents to cover them yet.  Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

For compressed extents, the range of checksum is covered by disk length,
and the disk length is different with ram length, so we need to use disk
length instead to get us the right checksum.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

A user reported a BUG_ON(ret) that occured during tree log replay.  Ret was
-EAGAIN, so what I think happened is that we removed an extent that covered
a bitmap entry and an extent entry.  We remove the part from the bitmap and
return -EAGAIN and then search for the next piece we want to remove, which
happens to be an entire extent entry, so we just free the sucker and return.
The problem is ret is still set to -EAGAIN so we trip the BUG_ON().  The
user used btrfs-zero-log so I'm not 100% sure this is what happened so I've
added a WARN_ON() to catch the other possibility.  Thanks,
Reported-by: Jan Steffens <jan.steffens@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

We drop the extent map tree lock while we're logging extents, so somebody
could come in and merge another extent into this one and screw up our
logging, or they could even remove us from the list which would keep us from
logging the extent or freeing our ref on it, so we need to make sure to not
clear LOGGING until after the extent is logged, and then we can merge it to
adjacent extents.  Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

From Pawel Moll:
- makes the V2P-CA15_A7 (a.k.a. TC2) work with 3.8 kernels
- improves vexpress-sysreg.c behaviour on arm64 platforms

* 'vexpress/fixes' of git://git.linaro.org/people/pawelmoll/linux:
  mfd: vexpress-sysreg: Don't skip initialization on probe
  ARM: vexpress: Enable A7 cores in V2P-CA15_A7's Device Tree
  ARM: vexpress: extend the MPIDR range used for pen release check

From Nicolas Ferre:
Here are fixes for AT91 that are mainly related to device tree.
One RM9200 setup option is the only C code change.
Some documentation changes can clarify the pinctrl use.
Then, some defconfig modifications are allowing the affected platforms
to boot.

* tag 'at91-fixes' of git://github.com/at91linux/linux-at91:
  ARM: at91/dts: correct comment in at91sam9x5.dtsi for mii
  ARM: at91/at91_dt_defconfig: add at91sam9n12 SoC to DT defconfig
  ARM: at91/at91_dt_defconfig: remove memory specification to cmdline
  ARM: at91/dts: add macb mii pinctrl config for kizbox
  ARM: at91: rm9200: remake the BGA as default version
  ARM: at91: fix gpios on i2c-gpio for RM9200 DT
  ARM: at91/at91sam9x5 DTS: add SCK USART pins
  ARM: at91/at91sam9x5 DTS: correct wrong PIO BANK values on u(s)arts
  ARM: at91/at91-pinctrl documentation: fix typo and add some details

The vexpress-sysreg driver does not have to be initialized
early, when the platform doesn't require this. Unfortunately
in such case it wasn't initialized correctly - master site
lookup and config bridge registration were missing. Fixed now.
Signed-off-by: Pawel Moll <pawel.moll@arm.com>

As the kernel is able to cope with multiple clusters,
uncomment the A7 cores in the Device Tree for V2P-CA15_A7
tile, making all 5 cores available to the user.
Signed-off-by: Pawel Moll <pawel.moll@arm.com>

In ARM multi-cluster systems the MPIDR affinity level 0 cannot be used as a
single cpu identifier, affinity levels 1 and 2 must be taken into account as
well.
This patch extends the MPIDR usage to affinity levels 1 and 2 in versatile
secondary cores start up code in order to compare the passed pen_release
value with the full-blown affinity mask.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Pawel Moll <pawel.moll@arm.com>

From Shawn Guo:

This is yet another critical imxfb fixes held off by absence of FB
maintainer for some time.

* tag 'imx-fixes-3.8-3' of git://git.linaro.org/people/shawnguo/linux-2.6:
  video: imxfb: Do not crash on reboot

From Jason Cooper:

mvebu fixes for v3.8-rc5
 - fix memory leak in mvebu/clk-cpu.c
 - use devm_ to correct/simplify error paths in mvsdio
 - add missing #interrupt-cells property in kirkwood

* tag 'mvebu_fixes_for_v3.8-rc5' of git://git.infradead.org/users/jcooper/linux:
  ARM: kirkwood: fix missing #interrupt-cells property
  mmc: mvsdio: use devm_ API to simplify/correct error paths.
  clk: mvebu/clk-cpu.c: fix memory leakage

Pull more USB fixes from Greg Kroah-Hartman:
 "Here are some more USB fixes for the 3.8-rc4 tree.

  Some gadget driver fixes, and finally resolved the ehci-mxc driver
  build issues (it's just some code moving around and being deleted)."

* tag 'usb-3.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  USB: EHCI: fix build error in ehci-mxc
  USB: EHCI: add a name for the platform-private field
  USB: EHCI: fix incorrect configuration test
  USB: EHCI: Move definition of EHCI_STATS to ehci.h
  USB: UHCI: fix IRQ race during initialization
  usb: gadget: FunctionFS: Fix missing braces in parse_opts
  usb: dwc3: gadget: fix ep->maxburst for ep0
  ARM: i.MX clock: Change the connection-id for fsl-usb2-udc
  usb: gadget: fsl_mxc_udc: replace MX35_IO_ADDRESS to ioremap
  usb: gadget: fsl-mxc-udc: replace cpu_is_xxx() with platform_device_id
  usb: musb: cppi_dma: drop '__init' annotation