When calling syscall service routines in kernel, some of arguments should
be user pointers but were missing __user markup on string literals.  Add
it.  Removes some sparse warnings.
Signed-off-by: NNamhyung Kim <namhyung@gmail.com>
Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Update the driver for the needed runtime power features.  Remove the old
user controlled power functions.

[akpm@linux-foundation.org: put PM code under CONFIG_PM]
Signed-off-by: NHong Liu <hong.liu@intel.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds support for the ADPS9802ALS sensor.

Cleanup by Alan Cox
	- move mutexes to cover more things
	- report I/O errors back to user space
	- report range and values in LUX
Signed-off-by: NAnantha Narayanan <anantha.narayanan@intel.com>
[The 4K and 64K in the hw spec actually means 4095 (12bit) and 65535 (16bit).]
Signed-off-by: NHong Liu <hong.liu@intel.com>
[Updated to match the ALS light API interface convention from Samu]
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Acked-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Our Moorestown platform has two max7315 chips which is covered by pca953x
i2c gpio driver.

A while ago this driver got updated with nested irq thread support, and it
broke the compatibity with "request_irq".  For example, the gpio_keys.c
driver can not work with this driver now.  This patch fixes the issue by
switching to generic_handle_irq.

Also fix the irq_base issue: irq_base == 0 is valid, and a "-1" value
should mean invalid. IRQ 0 is not a valid IRQ, irq_base of 0 is valid.
Signed-off-by: NAlek Du <alek.du@intel.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The LS driver will read the latest Lux measurement based upon the light
brightness and will report the LUX output through sysfs interface.

This hardware isn't quite the same as the ISL29003 so has a different
driver.

[akpm@linux-foundation.org: put PM code under #ifdef CONFIG_PM]
Signed-off-by: NKalhan Trisal <kalhan.trisal@intel.com>
[Runtime power management support added]
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
[Fixes to runtime PM]
Signed-off-by: NLiu Hong <hong.liu@intel.com>
[Cleanups and added checks for I2C errors, reworked the API to match the
 saner one agreed for other sensors]
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Prefix cname and ctype constants with CN/CT_.  This is especially for the
conflict on BUG which causes a build break if arch defines it as a inline
function, i.e.  MIPS.
Signed-off-by: NNamhyung Kim <namhyung@gmail.com>
Cc: Ankita Garg <ankita@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add short documentation for two ALS / proximity chip drivers.
Signed-off-by: NSamu Onkalo <samu.p.onkalo@nokia.com>
Acked-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is a driver for Avago APDS990X combined ALS and proximity sensor.

Interface is sysfs based.  The driver uses interrupts to provide new data.
The driver supports pm_runtime and regulator frameworks.

See Documentation/misc-devices/apds990x.txt for details
Signed-off-by: NSamu Onkalo <samu.p.onkalo@nokia.com>
Acked-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is a driver for ROHM BH1770GLC and OSRAM SFH7770 combined ALS and
proximity sensor.

Interface is sysfs based.  The driver uses interrupts to provide new data.
 The driver supports pm_runtime and regulator frameworks.

See Documentation/misc-devices/bh1770glc.txt for details
Signed-off-by: NSamu Onkalo <samu.p.onkalo@nokia.com>
Acked-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The ad5251/ad5252 devices have rdac1 and rdac3, but no rdac0.  So make
sure we use the right channels so userspace gets correct data and not just
garbage.
Signed-off-by: Nsteven miao <realmz6@gmail.com>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Cc: Michael Hennerich <michael.hennerich@analog.com>
Cc: Chris Verges <chrisv@cyberswitching.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add support for AD5270, AD5271, AD5272, AD5274 digital potentiometers.
Add 20-TP feature for AD5291 and AD5292 parts, and update feature list.
AD5291 rdac read back must be shifted by two.
Signed-off-by: NMichael Hennerich <michael.hennerich@analog.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Chris Verges <chrisv@cyberswitching.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is no runtime effect by this change.  It frees up namespace for
defines erroneously used.  This is required to actually support devices
requiring the namespace, added with "drivers/misc/ad525x_dpot.c: new
features".

All defines touched have the same value defined, after the change.
Signed-off-by: NMichael Hennerich <michael.hennerich@analog.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Chris Verges <chrisv@cyberswitching.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

phantom_probe() can fail in many places.  Add missing warning messages in
pci_enable_device() and pci_request_regions().
Signed-off-by: NRahul Ruikar <rahul.ruikar@gmail.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Silly though it is, completions and wait_queue_heads use foo_ONSTACK
(COMPLETION_INITIALIZER_ONSTACK, DECLARE_COMPLETION_ONSTACK,
__WAIT_QUEUE_HEAD_INIT_ONSTACK and DECLARE_WAIT_QUEUE_HEAD_ONSTACK) so I
guess workqueues should do the same thing.

s/INIT_WORK_ON_STACK/INIT_WORK_ONSTACK/
s/INIT_DELAYED_WORK_ON_STACK/INIT_DELAYED_WORK_ONSTACK/

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The lock number in /proc/locks (first field) is implemented by a counter
(private field of struct seq_file) which is incremented at each call of
locks_show() and reset to 1 in locks_start() whatever the offset is.  It
should be reset according to the actual position in the list.  Because of
this, the numbering erratically restarts at 1 several times when reading a
long /proc/locks file.

Moreover, locks_show() can be called twice to print a single line thus
skipping a number.  The counter should be incremented in locks_next().

And last, pos is a loff_t, which can be bigger than a pointer, so we don't
use the pointer as an integer anymore, and allocate a loff_t instead.
Signed-off-by: NJerome Marchand <jmarchan@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move the EXPORTFS kconfig symbol out of the NETWORK_FILESYSTEMS block
since it provides a library function that can be (and is) used by other
(non-network) filesystems.

This also eliminates a kconfig dependency warning:

warning: (XFS_FS && BLOCK || NFSD && NETWORK_FILESYSTEMS && INET && FILE_LOCKING && BKL) selects EXPORTFS which has unmet direct dependencies (NETWORK_FILESYSTEMS)
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alex Elder <aelder@sgi.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

bh->b_private is initialized within init_buffer(), thus this assignment is
redundant.
Signed-off-by: NNamhyung Kim <namhyung@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The new init ramfs format (cpio based) requires an alignment of 4 (per the
documentation and per the source files themselves).  As for compressed
sources, the decompressors can all deal with unaligned buffers.

The cpio source is also found in the __init sections of the kernel, so
once they are read and expanded into a tmpfs, the source is freed.  That
means there is no need to force page alignment here either.

This has been used on Blackfin systems for many releases without issue.
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With the recent change "net: remove time limit in process_backlog()", the
softnet_data variable changed from "DEFINE_PER_CPU()" to
"DEFINE_PER_CPU_ALIGNED()" which moved it from the .data section to the
.data.shared_align section.  I'm not saying this patch is wrong, just that
is what caused me to notice this larger problem.  No one else in the
kernel is using this aligned macro variant, so I imagine that's why no one
has noticed yet.

Since .data..shared_align isn't declared in any vmlinux files that I can
see, the linker just places it last.  This "just works" for most people,
but when building a ROM kernel on Blackfin systems, it causes section
overlap errors:

bfin-uclinux-ld.real:
	section .init.data [00000000202e06b8 -> 00000000202e48b7] overlaps
	section .data.shared_aligned [00000000202e06b8 -> 00000000202e0723]

I imagine other arches which support the ROM config option and thus do
funky placement would see similar issues ...

On x86, it is stuck in a dedicated section at the end:
 [8] .data             PROGBITS ffffffff810ec000 2ec0000303a8 00 WA 0 0 4096
 [9] .data.shared_alig PROGBITS ffffffff8111c3c0 31c3c00000c8 00 WA 0 0 64

So make sure we include this section in the DATA_DATA macro so that it is
placed in the right location.
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Cc: Greg Ungerer <gerg@snapgear.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix up truncation (ssize_t->int).  This only matters with >2G
reads/writes, which the kernel doesn't permit.
Signed-off-by: NEdward Shishkin <edward@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

ihex firmwares can include a jump address for starting execution.  Add a
-j option which will cause this to be written into the generated file as a
record with address zero and data consisting of the address to jump to,
allowing drivers to make use of this information.

This format is chosen because it most closely follows the original ihex
format, though it may make more sense to write a record with length zero
and the address stored as the address.  The records are not omitted by
default since our ihex format does not include record type information and
so including additional records may lead to confusion.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 7909b1c6 ("fuse: don't use atomic kmap") removed KM_USER0 usage
from fuse/dev.c.  Switch KM_USER1 uses to KM_USER0 for clarity.  Also
replace open coded clear_highpage().
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

After all that's what they are intended for.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

gcc aligns strings as a performance consideration for those cases where
strings are being used a lot.

Their use is not performance critical, and hence it seems better to save
some space.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The whole point to using the strict functions is to check the return
value.  If you don't, strict_strto*() will return you uninitialised
garbage.  Offenders have been observed in the wild.
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Long ago, PT_TRACESYS_OFF and friends were introduced as hard defines to
avoid straight constants in assembler parts of linux m68k.  They are not
used anymore, and were not updated to follow changes in linux kernel.
Remove them.  When similar constants are needed, they are now generated
using asm-offsets.c.
Signed-off-by: NPhilippe De Muyter <phdm@macqel.be>
Acked-by: NMike Frysinger <vapier@gentoo.org>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Acked-by: NGreg Ungerer <gerg@uclinux.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the new {max,min}3 macros to save some cycles and bytes on the stack.
This patch substitutes trivial nested macros with their counterpart.
Signed-off-by: NHagen Paul Pfeifer <hagen@jauu.net>
Cc: Joe Perches <joe@perches.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Roland Dreier <rolandd@cisco.com>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Introduce two additional min/max macros to compare three operands.  This
will save some cycles as well as some bytes on the stack and last but not
least more pleasing as macro nesting.

[akpm@linux-foundation.org: fix warnings]
Signed-off-by: NHagen Paul Pfeifer <hagen@jauu.net>
Cc: Joe Perches <joe@perches.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Roland Dreier <rolandd@cisco.com>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Some code cleanups for hostfs.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch removes __do_IRQ() from user mode linux.  __do_IRQ is deprecated.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With glibc 2.11 or later that was built with --enable-multi-arch, the UML
link fails with undefined references to __rel_iplt_start and similar
symbols.  In recent binutils, the default linker script defines these
symbols (see ld --verbose).  Fix the UML linker scripts to match the new
defaults for these sections.
Signed-off-by: NRoland McGrath <roland@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I think that it's better to detect DMA misuse at build time rather than
calling BUG_ON.  Architectures that can't do DMA need to define
CONFIG_NO_DMA.

Thanks to Sam Ravnborg for explaining how CONFIG_NO_DMA and CONFIG_HAS_DMA
work:

http://marc.info/?l=linux-kernel&m=128359913825550&w=2

HAS_DMA is defined like this:

config HAS_DMA
        boolean
        depends on !NO_DMA
        default y

So to set HAS_DMA to true an arch should do:
1) Do not define NO_DMA
2) Define NO_DMA abd set it to 'n'

Must archs - including um - used principle 1).

In the um case we want to say that we do NOT have any DMA.
This can be done in two ways.
a) define NO_DMA and set it to 'y'
b) redefine HAS_DMA and set it to 'n'.

The patch you provided used principle b) where other archs use principle a).
So I suggest you should use principle a) for um too.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

T2 are the only alpha SMP systems that do HAE switching at runtime, which
is fundamentally racy on SMP.  This patch limits MMIO space on T2 to HAE0
only, like we did on MCPCIA (rawhide) long ago.  This leaves us with only
112 Mb of PCI MMIO (128 Mb HAE aperture minus 16 Mb reserved for EISA),
but since linux PCI allocations are reasonably tight, it should be enough
for sane hardware configurations.

Also, fix a typo in MCPCIA_FROB_MMIO macro which shouldn't call set_hae()
if MCPCIA_ONE_HAE_WINDOW is defined.  It's more for correctness, as
set_hae() is a no-op anyway in that case.
Signed-off-by: NIvan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Matt Turner <mattst88@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Structure info is copied to userland with some padding fields unitialized.
It leads to leaking of stack memory.

[akpm@linux-foundation.org: remove now-unneeded zeroing of info->hi_ireqfreq]
Signed-off-by: NVasiliy Kulikov <segooon@gmail.com>
Cc: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

$./hpet_example info /dev/hpet
-hpet: executing info
hpet_info: hi_irqfreq 0x0 hi_flags 0x0 hi_hpet 0 hi_timer 2
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: "Venkatesh Pallipadi (Venki)" <venki@google.com>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix the following style problems:

WARNING: Use #include <linux/uaccess.h> instead of <asm/uaccess.h>
WARNING: Use #include <linux/io.h> instead of <asm/io.h>
ERROR: code indent should use tabs where possible
ERROR: do not initialise statics to 0 or NULL
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>
Cc: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Jaswinder Singh Rajput wrote:
> By executing Documentation/timers/hpet_example.c
>
> for polling, I requested for 3 iterations but it seems iteration work
> for only 2 as first expired time is always very small.
>
> # ./hpet_example poll /dev/hpet 10 3
> -hpet: executing poll
> hpet_poll: info.hi_flags 0x0
> hpet_poll: expired time = 0x13
> hpet_poll: revents = 0x1
> hpet_poll: data 0x1
> hpet_poll: expired time = 0x1868c
> hpet_poll: revents = 0x1
> hpet_poll: data 0x1
> hpet_poll: expired time = 0x18645
> hpet_poll: revents = 0x1
> hpet_poll: data 0x1

Clearing the HPET interrupt enable bit disables interrupt generation
but does not disable the timer, so the interrupt status bit will still
be set when the timer elapses.  If another interrupt arrives before
the timer has been correctly programmed (due to some other device on
the same interrupt line, or CONFIG_DEBUG_SHIRQ), this results in an
extra unwanted interrupt event because the status bit is likely to be
set from comparator matches that happened before the device was opened.

Therefore, we have to ensure that the interrupt status bit is and
stays cleared until we actually program the timer.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Reported-by: NJaswinder Singh Rajput <jaswinderlinux@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Bob Picco <bpicco@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When the initialization code in hpet finds a memory resource and does not
find an IRQ, it does not unmap the memory resource previously mapped.

There are buggy BIOSes which report resources exactly like this and what
is worse the memory region bases point to normal RAM.  This normally would
not matter since the space is not touched.  But when PAT is turned on,
ioremap causes the page to be uncached and sets this bit in page->flags.

Then when the page is about to be used by the allocator, it is reported
as:

BUG: Bad page state in process md5sum  pfn:3ed00
page:ffffea0000dbd800 count:0 mapcount:0 mapping:(null) index:0x0
page flags: 0x20000001000000(uncached)
Pid: 7956, comm: md5sum Not tainted 2.6.34-12-desktop #1
Call Trace:
 [<ffffffff810df851>] bad_page+0xb1/0x100
 [<ffffffff810dfa45>] prep_new_page+0x1a5/0x1c0
 [<ffffffff810dfe01>] get_page_from_freelist+0x3a1/0x640
 [<ffffffff810e01af>] __alloc_pages_nodemask+0x10f/0x6b0
...

In this particular case:

1) HPET returns 3ed00000 as memory region base, but it is not in
reserved ranges reported by the BIOS (excerpt):
 BIOS-e820: 0000000000100000 - 00000000af6cf000 (usable)
 BIOS-e820: 00000000af6cf000 - 00000000afdcf000 (reserved)

2) there is no IRQ resource reported by HPET method. On the other
hand, the Intel HPET specs (1.0a) says (3.2.5.1):
_CRS (
  // Report 1K of memory consumed by this Timer Block
  memory range consumed
  // Optional: only used if BIOS allocates Interrupts [1]
  IRQs consumed
)

[1] For case where Timer Block is configured to consume IRQ0/IRQ8 AND
Legacy 8254/Legacy RTC hardware still exists, the device objects
associated with 8254 & RTC devices should not report IRQ0/IRQ8 as
"consumed resources".

So in theory we should check whether if it is the case and use those
interrupts instead.

Anyway the address reported by the BIOS here is bogus, so non-presence
of IRQ doesn't mean the "optional" part in point 2).

Since I got no reply previously, fix this by simply unmapping the space
when IRQ is not found and memory region was mapped previously.  It would
be probably more safe to walk the resources again and unmap appropriately
depending on type.  But as we now use only ioremap for both 2 memory
resource types, it is not necessarily needed right now.

Addresses https://bugzilla.novell.com/show_bug.cgi?id=629908Reported-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Acked-by: NClemens Ladisch <clemens@ladisch.de>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Simple code for reducing list_empty(&source) check.
Signed-off-by: NBob Liu <lliubbo@gmail.com>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NWu Fengguang <fengguang.wu@intel.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>