thinkpad-acpi: kill hotkey_thread_mutex

hotkey_kthread() does try_to_freeze() under hotkey_thread_mutex.

We can simply kill this mutex, hotkey_poll_stop_sync() does not need to
serialize with hotkey_kthread().  When kthread_stop() returns the thread
is already dead, it called do_exit()->complete_vfork_done().

Reported-by: Artem Savkov <artem.savkov@gmail.com>
Reported-by: Maciej Rutecki <maciej.rutecki@gmail.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Matthew Garrett <matthew.garrett@nebula.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Reviewed-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

revert "ipc: don't allocate a copy larger than max"

Revert 88b9e456b164.  Dave has confirmed that this was causing oopses
during trinity testing.

Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Stanislav Kinsbursky <skinsbursky@parallels.com>
Reported-by: Dave Jones <davej@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Merge remote-tracking branch 'lzo-update/lzo-update'

Merge remote-tracking branch 'clk/clk-next'

Merge remote-tracking branch 'signal/for-next'

Conflicts:
arch/mips/kernel/linux32.c
arch/tile/Kconfig
arch/tile/kernel/compat.c
fs/compat.c
fs/read_write.c
fs/read_write.h
fs/splice.c
include/asm-generic/unistd.h

Merge remote-tracking branch 'userns/for-next'

Merge remote-tracking branch 'pwm/for-next'

Merge remote-tracking branch 'tegra/for-next'

Conflicts:
arch/arm/mach-tegra/tegra.c
drivers/clocksource/tegra20_timer.c

Merge remote-tracking branch 'samsung/for-next'

Merge remote-tracking branch 'renesas/next'

Merge remote-tracking branch 'msm/for-next'

Merge remote-tracking branch 'imx-mxs/for-next'

Conflicts:
arch/arm/Kconfig.debug
arch/arm/mach-imx/cpufreq.c
drivers/clocksource/Makefile

Merge remote-tracking branch 'ep93xx/ep93xx-for-next'

Merge remote-tracking branch 'bcm2835/for-next'

Conflicts:
arch/arm/Kconfig
arch/arm/Kconfig.debug

Merge remote-tracking branch 'arm-soc/for-next'

Merge remote-tracking branch 'mailbox/dbx500-prcmu-mailbox'

Merge remote-tracking branch 'gen-gpio/for_next'

Conflicts:
arch/sh/kernel/cpu/sh2a/Makefile

Merge remote-tracking branch 'gpio-lw/for-next'

Merge remote-tracking branch 'gpio/gpio/next'

Merge remote-tracking branch 'irqdomain/irqdomain/next'

Merge remote-tracking branch 'vhost/linux-next'

Conflicts:
drivers/vhost/Makefile

Merge remote-tracking branch 'pinctrl/for-next'

Merge remote-tracking branch 'bcon/master'

Conflicts:
drivers/block/Kconfig

Merge remote-tracking branch 'char-misc/char-misc-next'

Merge remote-tracking branch 'staging/staging-next'

Conflicts:
drivers/staging/ccg/f_fs.c
drivers/staging/ccg/rndis.c
drivers/staging/dgrp/dgrp_dpa_ops.c
drivers/staging/dgrp/dgrp_mon_ops.c
drivers/staging/dgrp/dgrp_net_ops.c
drivers/staging/dgrp/dgrp_ports_ops.c
drivers/staging/dgrp/dgrp_specproc.c

Merge remote-tracking branch 'usb-gadget/next'

Conflicts:
drivers/usb/chipidea/udc.c
drivers/usb/gadget/net2272.c
drivers/usb/gadget/net2280.c
drivers/usb/host/ehci-tegra.c

Merge remote-tracking branch 'usb/usb-next'

Conflicts:
drivers/usb/serial/usb-serial.c

Merge remote-tracking branch 'tty/tty-next'

Merge remote-tracking branch 'driver-core/driver-core-next'

Merge remote-tracking branch 'leds/for-next'

Merge remote-tracking branch 'regmap/for-next'

Merge remote-tracking branch 'drivers-x86/linux-next'

Conflicts:
drivers/platform/x86/chromeos_laptop.c

Merge remote-tracking branch 'workqueues/for-next'

Merge remote-tracking branch 'percpu/for-next'

Merge remote-tracking branch 'xen-two/linux-next'

Merge remote-tracking branch 'kvm-ppc/kvm-ppc-next'

Merge remote-tracking branch 'kvm/linux-next'

Conflicts:
drivers/s390/kvm/virtio_ccw.c

Merge remote-tracking branch 'rcu/rcu/next'

Merge remote-tracking branch 'ftrace/for-next'

Conflicts:
kernel/trace/ftrace.c

Merge remote-tracking branch 'tip/auto-latest'

Merge remote-tracking branch 'spi-mb/spi-next'

Merge remote-tracking branch 'trivial/for-next'

Conflicts:
Documentation/virtual/virtio-spec.txt

Merge remote-tracking branch 'vfio/next'

Merge remote-tracking branch 'iommu/next'

Merge remote-tracking branch 'watchdog/master'

Merge remote-tracking branch 'selinux/master'

Merge remote-tracking branch 'security/next'

Merge remote-tracking branch 'regulator/for-next'

Merge remote-tracking branch 'omap_dss2/for-next'

Merge remote-tracking branch 'battery/master'

Merge remote-tracking branch 'mfd/master'

Merge remote-tracking branch 'md/for-next'

Merge remote-tracking branch 'slab/for-next'

Merge remote-tracking branch 'kgdb/kgdb-next'

Merge remote-tracking branch 'mmc/mmc-next'

Merge branch 'device-mapper/master'

Merge remote-tracking branch 'block/for-next'

Conflicts:
drivers/block/drbd/drbd_proc.c

Merge remote-tracking branch 'cgroup/for-next'

Conflicts:
include/linux/res_counter.h

Merge remote-tracking branch 'input/next'

Merge remote-tracking branch 'virtio/virtio-next'

Conflicts:
drivers/char/virtio_console.c

Merge remote-tracking branch 'modules/modules-next'

Merge remote-tracking branch 'sound-asoc/for-next'

Merge remote-tracking branch 'sound/for-next'

Merge remote-tracking branch 'drm-intel/drm-intel-next-queued'

Merge remote-tracking branch 'crypto/master'

Merge remote-tracking branch 'l2-mtd/master'

Merge remote-tracking branch 'bluetooth/master'

Merge remote-tracking branch 'wireless-next/master'

Conflicts:
drivers/nfc/microread/mei.c
net/mac80211/sta_info.c
net/wireless/core.h

Merge remote-tracking branch 'ipsec-next/master'

Merge remote-tracking branch 'net-next/master'

Conflicts:
drivers/net/wireless/rt2x00/rt2x00pci.c
drivers/nfc/microread/mei.c

Merge remote-tracking branch 'dmaengine/next'

Conflicts:
drivers/dma/ioat/dma_v3.c

Merge remote-tracking branch 'slave-dma/next'

Merge remote-tracking branch 'target-updates/for-next'

Merge remote-tracking branch 'thermal/next'

Merge remote-tracking branch 'cpuidle/cpuidle-next'

Conflicts:
drivers/base/power/qos.c

Merge remote-tracking branch 'idle/next'

Merge remote-tracking branch 'pm/linux-next'

Merge remote-tracking branch 'pstore/master'

Merge remote-tracking branch 'kbuild/for-next'

Merge remote-tracking branch 'v4l-dvb/master'

Conflicts:
drivers/media/pci/bt8xx/bttv-input.c
drivers/media/platform/Kconfig
drivers/staging/media/go7007/go7007-driver.c

Merge remote-tracking branch 'hwmon-staging/hwmon-next'

Merge branch 'jdelvare-hwmon/master'

Merge remote-tracking branch 'i2c/i2c/for-next'

Merge remote-tracking branch 'hid/for-next'

Conflicts:
drivers/hid/hid-multitouch.c

Merge remote-tracking branch 'pci/next'

Merge remote-tracking branch 'vfs/for-next'

Merge remote-tracking branch 'xfs/for-next'

Conflicts:
fs/xfs/xfs_iomap.c

Merge remote-tracking branch 'ubifs/linux-next'

Merge remote-tracking branch 'ocfs2/linux-next'

Merge remote-tracking branch 'nfsd/nfsd-next'

Merge remote-tracking branch 'nfs/linux-next'

Merge remote-tracking branch 'logfs/master'

Merge remote-tracking branch 'jfs/jfs-next'

Merge remote-tracking branch 'gfs2/master'

Merge remote-tracking branch 'f2fs/dev'

20130403/ext4

Merge remote-tracking branch 'ext3/for_next'

Merge remote-tracking branch 'cifs/for-next'

Merge remote-tracking branch 'btrfs/next'

Merge remote-tracking branch 'tile/master'