Commit f23eb2b2 ('tty: stop using "delayed_work" in the tty layer')
ended up causing hung machines on UP with no preemption, because the
work routine to flip the buffer data to the ldisc would endlessly re-arm
itself if the destination buffer had filled up.

With the delayed work, that only caused a timer-driving polling of the
tty state every timer tick, but without the delay we just ended up with
basically a busy loop instead.

Stop the insane polling, and instead make the code that opens up the
receive room re-schedule the buffer flip work.  That's what we should
have been doing anyway.

This same "poll for tty room" issue is almost certainly also the cause
of excessive kworker activity when idle reported by Dave Jones, who also
reported "flush_to_ldisc executing 2500 times a second" back in Nov 2010:

  http://lkml.org/lkml/2010/11/30/592

which is that silly flushing done every timer tick.  Wasting both power
and CPU for no good reason.
Reported-and-tested-by: NAlexander Beregalov <a.beregalov@gmail.com>
Reported-and-tested-by: NSitsofe Wheeler <sitsofe@yahoo.com>
Cc: Greg KH <gregkh@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, UV: Fix kdump reboot
  x86, amd-nb: Rename CPU PCI id define for F4
  sound: Add delay.h to sound/soc/codecs/sn95031.c
  x86, mtrr, pat: Fix one cpu getting out of sync during resume
  x86, microcode: Unregister syscore_ops after microcode unloaded
  x86: Stop including <linux/delay.h> in two asm header files

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

* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: Fix rebalance interval calculation
  sched, doc: Beef up load balancing description
  sched: Leave sched_setscheduler() earlier if possible, do not disturb SCHED_FIFO tasks

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

* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf: Fix task_struct reference leak
  perf: Fix task context scheduling
  perf: mmap 512 kiB by default
  perf: Rebase max unprivileged mlock threshold on top of page size
  perf tools: Fix NO_NEWT=1 python build error
  perf symbols: Properly align symbol_conf.priv_size
  perf tools: Emit clearer message for sys_perf_event_open ENOENT return
  perf tools: Fixup exit path when not able to open events
  perf symbols: Fix vsyscall symbol lookup
  oprofile, x86: Allow setting EDGE/INV/CMASK for counter events

Merge branch 'core-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:
  rcu: create new rcu_access_index() and use in mce
  WARN_ON_SMP(): Add comment to explain ({0;})

Fix build warnings caused by removal of *filp arg in struct
usb_serial_driver.

These changes were missed somehow in commits 00a0d0d6 ("tty: remove
filp from the USB tty ioctls") and 60b33c13 ("tiocmget: kill off
the passing of the struct file")

  drivers/usb/serial/mct_u232.c:159: warning: initialization from incompatible pointer type
  drivers/usb/serial/opticon.c:627: warning: initialization from incompatible pointer type
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6:
  [media] radio: wl128x: Update registration process with ST
  [media] staging: altera-jtag needs delay.h

* 'unicore32' of git://git.kernel.org/pub/scm/linux/kernel/git/epip/linux-2.6-unicore32:
  unicore32 framebuffer fix: get videomemory by __get_free_pages() and make it floatable
  unicore32 core architecture: remove duplicated #include
  unicore32 rtc driver fix: cleanup irq_set_freq and irq_set_state
  unicore32 fix: remove arch-specific futex support
  unicore32 ldscript fix: add cacheline parameter to PERCPU() macro

* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/staging:
  hwmon: twl4030-madc-hwmon: add "platform:" prefix for platform modalias

The ADJ_SETOFFSET bit added in commit 094aa188 ("ntp: Add ADJ_SETOFFSET
mode bit") also introduced a way for any user to change the system time.
Sneaky or buggy calls to adjtimex() could set

    ADJ_OFFSET_SS_READ | ADJ_SETOFFSET

which would result in a successful call to timekeeping_inject_offset().
This patch fixes the issue by adding the capability check.
Signed-off-by: NRichard Cochran <richard.cochran@omicron.at>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix the following section mismatch warning.

  WARNING: drivers/rtc/built-in.o(.data+0xa0): Section mismatch in reference from the variable vrtc_mrst_platform_driver to the function .init.text:vrtc_mrst_platform_probe()
  The variable vrtc_mrst_platform_driver references the function __init vrtc_mrst_platform_probe()
  If the reference is valid then annotate the variable with __init* or __refdata (see linux/init.h) or name the variable:
    *_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console,
Signed-off-by: NMajor Lee <major_lee@wistron.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

1. get videomemory by __get_free_pages() in fb-puv3.c
2. remove resource reservation for old fixed UNIGFX_MMAP & UVC_MMAP space
3. remove unused macros: PKUNTIY_UNIGFX_MMAP_BASE, PKUNITY_UNIGFX_MMAP_SIZE,
	PKUNITY_UVC_MMAP_BASE, PKUNITY_UVC_MMAP_SIZE and KUSER_UNIGFX_BASE
4. remove unused header linux/vmalloc.h in fb-puv3.h
Signed-off-by: NGuan Xuetao <gxt@mprc.pku.edu.cn>
Acked-by: NArnd Bergmann <arnd@arndb.de>

Remove duplicated #include('s) in
  arch/unicore32/kernel/traps.c
Signed-off-by: NHuang Weiyi <weiyi.huang@gmail.com>
Acked-by: NGuan Xuetao <gxt@mprc.pku.edu.cn>

Signed-off-by: NGuan Xuetao <gxt@mprc.pku.edu.cn>

The futex functions in unicore32 are not used and verified,
so just replaced by asm-generic version.
Signed-off-by: NGuan Xuetao <gxt@mprc.pku.edu.cn>
Acked-by: NArnd Bergmann <arnd@arndb.de>

Also, adjust cacheline parameter of RW_DATA_SECTION and EXCEPTION_TABLE
Signed-off-by: NGuan Xuetao <gxt@mprc.pku.edu.cn>
Acked-by: NArnd Bergmann <arnd@arndb.de>

* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6:
  [IA64] fix build warning: argument 1 of 'irqd_irq_disabled'

Merge branch 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu into core/urgent

In commit f5e5bf08
  ia64: Use irqd_irq_disabled() instead of desc->status access

Thomas forgot to convert from irq to *irq_data.

Add a call to irq_get_irq_data() to fix that.
Signed-off-by: NTony Luck <tony.luck@intel.com>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
  ALSA: pcm: fix infinite loop in snd_pcm_update_hw_ptr0()
  ALSA: HDA: Add dock mic quirk for Lenovo Thinkpad X220
  ALSA: ens1371: fix Creative Ectiva support
  ALSA: firewire-speakers: fix hang when unplugging a running device
  ASoC: Fix CODEC device name for Corgi
  ALSA: hda - Fix pin-config of Gigabyte mobo
  ASoC: imx: fix burstsize for DMA
  ASoC: imx: set watermarks for mx2-dma
  ASoC: twl6040: Return -ENOMEM if create_singlethread_workqueue fails
  ASoC: tlv320dac33: Restore L/R DAC power control register
  ASoC: Explicitly say registerless widgets have no register
  ASoC: tlv320dac33: Fix inconsistent spinlock usage

When period interrupts are disabled, snd_pcm_update_hw_ptr0() compares
the current time against the time estimated for the current hardware
pointer to detect xruns.  The somewhat fuzzy threshold in the while loop
makes it possible that hdelta becomes negative; the comparison being
done with unsigned types then makes the loop go through the entire 263
negative range, and, depending on the value, never reach an unsigned
value that is small enough to stop the loop.  Doing this with interrupts
disabled results in the machine locking up.

To prevent this, ensure that the loop condition uses signed types for
both operands so that the comparison is correctly done.

Many thanks to Kelly Anderson for debugging this.
Reported-by: NNix <nix@esperi.org.uk>
Reported-by: N"Christopher K." <c.krooss@googlemail.com>
Reported-and-tested-by: NKelly Anderson <kelly@silka.with-linux.com>
Signed-off-by: NKelly Anderson <kelly@silka.with-linux.com>
[cl: remove unneeded casts; use a temp variable]
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Cc: 2.6.38 <stable@kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  kdump: Allow shrinking of kdump region to be overridden
  powerpc/pmac/smp: Remove no-longer needed preempt workaround
  powerpc/smp: Increase vdso_data->processorCount, not just decrease it
  powerpc/smp: Create idle threads on demand and properly reset them
  powerpc/smp: Don't expose per-cpu "cpu_state" array
  powerpc/pmac/smp: Fix CPU hotplug crashes on some machines
  powerpc/smp: Add a smp_ops->bringup_up() done callback
  powerpc/pmac: Rename cpu_state in therm_pm72 to avoid collision
  powerpc/pmac/smp: Properly NAP offlined CPU on G5
  powerpc/pmac/smp: Remove HMT changes for PowerMac offline code
  powerpc/pmac/smp: Consolidate 32-bit and 64-bit PowerMac cpu_die in one file
  powerpc/pmac/smp: Fixup smp_core99_cpu_disable() and use it on 64-bit
  powerpc/pmac/smp: Rename fixup_irqs() to migrate_irqs() and use it on ppc32
  powerpc/pmac/smp: Fix 32-bit PowerMac cpu_die
  powerpc/smp: Remove unused smp_ops->cpu_enable()
  powerpc/smp: Remove unused generic_cpu_enable()
  powerpc/smp: Fix generic_mach_cpu_die()
  powerpc/smp: soft-replugged CPUs must go back to start_secondary
  powerpc: Make decrementer interrupt robust against offlined CPUs

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6:
  sparc32: Pass task_struct to schedule_tail() in ret_from_fork
  apbuart: Depend upon sparc.
  sparc64: Fix section mis-match errors.
  sparc32,leon: Fixed APBUART frequency detection
  sparc32, leon: APBUART driver must use archdata to get IRQ number
  sparc: Hook up syncfs system call.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
  appletalk: Fix OOPS in atalk_release().
  mlx4: Fixing bad size of event queue buffer
  mlx4: Fixing use after free
  bonding:typo in comment
  sctp: Pass __GFP_NOWARN to hash table allocation attempts.
  connector: convert to synchronous netlink message processing
  fib: add rtnl locking in ip_fib_net_exit
  atm/solos-pci: Don't flap VCs when carrier state changes
  atm/solos-pci: Don't include frame pseudo-header on transmit hex-dump
  atm/solos-pci: Use VPI.VCI notation uniformly.
  Atheros, atl2: Fix mem leaks in error paths of atl2_set_eeprom
  netdev: fix mtu check when TSO is enabled
  net/usb: Ethernet quirks for the LG-VL600 4G modem
  phylib: phy_attach_direct: phy_init_hw can fail, add cleanup
  bridge: mcast snooping, fix length check of snooped MLDv1/2
  via-ircc: Pass PCI device pointer to dma_{alloc, free}_coherent()
  via-ircc: Use pci_{get, set}_drvdata() instead of static pointer variable
  net: gre: provide multicast mappings for ipv4 and ipv6
  bridge: Fix compilation warning in function br_stp_recalculate_bridge_id()
  net: Fix warnings caused by MAX_SKB_FRAGS change.

The MCE subsystem needs to sample an RCU-protected index outside of
any protection for that index.  If this was a pointer, we would use
rcu_access_pointer(), but there is no corresponding rcu_access_index().
This commit therefore creates an rcu_access_index() and applies it
to MCE.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: NZdenek Kabelac <zkabelac@redhat.com>

On ppc64 the crashkernel region almost always overlaps an area of firmware.
This works fine except when using the sysfs interface to reduce the kdump
region. If we free the firmware area we are guaranteed to crash.

Rename free_reserved_phys_range to crash_free_reserved_phys_range and make
it a weak function so we can override it.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

The generic code properly re-initializes the preempt count in the
idle thread now
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Instead of creating idle threads at boot for all possible CPUs, we
create them on demand, like x86 or ARM, and we properly call init_idle
to re-initialize an idle thread when a CPU was unplugged and is now
re-plugged.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Instead, keep it static, expose an accessor and use that from
the PowerMac code. Avoids easy namespace collisions and will
make it easier to consolidate with other implementations.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

On some machines that use i2c to synchronize the timebases (such
as PowerMac7,2/7,3 G5 machines), hotplug CPU would crash when
putting back a new CPU online due to the underlying i2c bus being
closed.

This uses the newly added bringup_done() callback to move the close
along with other housekeeping calls, and adds a CPU notifier to
re-open the i2c bus around subsequent hotplug operations
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This allows us to stop abusing smp_ops->setup_cpu() for cleanup
tasks that have to take place after the initial boot time CPU
bringup.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This collides with the cpu_state in our SMP code, use processor_state
instead.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

The current code soft-disables, and then goes to NAP mode which
turns interrupts on. That means that if an interrupt occurs, we
will hit the masked interrupt code path which isn't what we want,
as it will return with EE off, which will either get us out of
NAP mode, or fail to enter it (according to spec).

Instead, let's just rely on the fact that it is safe to take
decrementer interrupts on an offline CPU and leave interrupts
enabled. We can also get rid of the special case in asm for
power4_cpu_offline_powersave() and just use power4_idle().
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Those instructions do nothing on non-threaded processors such
as 970's used on those machines.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Use the generic code, just add the MPIC priority setting,

I don't see any use in mucking around with the decrementer,
as 32-bit will have EE off all along, and 64-bit will be able
to deal with it.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Use generic cpu_state, call idle_task_exit() properly, and
remove smp_core99_cpu_die() which isn't useful, the generic
function does the job just fine.