The PCM043 is a i.MX35 based board from Phytec also known as the
phyCORE-i.MX35.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

This iomux is called iomux-v3 in the tree because it is the third known
incarnation of MXC iomuxers. It is not only found on the MX35 but also
on the MX51 and probably others.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

The i.MX31 ARM11 core is not a v6K core. Disable this option as it
is incompatible with non v6K cores.
Signed-off-by: Magnus Lilja <lilja.magnus@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Before this patch I got the following line in my dmesg:

	[    0.000000] BUG: mapping for 0xd4000000 at 0xeb000000 overlaps vmalloc space

VMALLOC_END is 0xf4000000 and there are the following other mappings
defined for mx27ads:

	(0xa0500000,+0x00001000) maps to 0xffff0000
	(0x10000000,+0x00100000) maps to 0xf4000000
	(0x80000000,+0x00100000) maps to 0xf4100000
	(0xd8000000,+0x00100000) maps to 0xf4200000

So map PBC to 0xf4300000.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

On i.MX31 I sometimes get spurious interrupts. There is no need
to crash the whole system when this happens. Instead, silently
ignore it.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

We want to have a mx31_defconfig file that builds a kernel that is able
to boot on all support mx31 systems and thus also can be better tested
by automatic build scripts. For these reasons, this config file is not
needed anymore.
Signed-off-by: Valentin Longchamp <valentin.longchamp@epfl.ch>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

All i.MX platforms support <linux/clk.h> calls and should select HAVE_CLK.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

On MX2 platforms imx_dma_request() calls request_irq() which may sleep
with interrupts disabled.
Signed-off-by: Martin Fuzzey <mfuzzey@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

The sequence
	imx_dma_request()
	imx_dma_enable()
	imx_dma_free()
left the dma channel in_use mode and did not release the timer.
Signed-off-by: Martin Fuzzey <mfuzzey@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

* 'for-linus' of git://oss.sgi.com/xfs/xfs:
  xfs: fix getbmap vs mmap deadlock
  xfs: a couple getbmap cleanups
  xfs: add more checks to superblock validation
  xfs_file_last_byte() needs to acquire ilock

The powerpc kernel always requires an Open Firmware like device tree
to supply device information.  On systems without OF, this comes from
a flattened device tree blob.  This blob is usually generated by dtc,
a tool which compiles a text description of the device tree into the
flattened format used by the kernel.  Sometimes, the bootwrapper makes
small changes to the pre-compiled device tree blob (e.g. filling in
the size of RAM).  To do this it uses the libfdt library.

Because these are only used on powerpc, the code for both these tools
is included under arch/powerpc/boot (these were imported and are
periodically updated from the upstream dtc tree).

However, the microblaze architecture, currently being prepared for
merging to mainline also uses dtc to produce device tree blobs.  A few
other archs have also mentioned some interest in using dtc.
Therefore, this patch moves dtc and libfdt from arch/powerpc into
scripts, where it can be used by any architecture.

The vast bulk of this patch is a literal move, the rest is adjusting
the various Makefiles to use dtc and libfdt correctly from their new
locations.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/configfs:
  configfs: Fix Trivial Warning in fs/configfs/symlink.c

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6:
  ide-cd: fix REQ_QUIET tests in cdrom_decode_status

Fix up trivial conflicts in include/linux/blkdev.h

* master.kernel.org:/home/rmk/linux-2.6-arm: (45 commits)
  [ARM] 5489/1: ARM errata: Data written to the L2 cache can be overwritten with stale data
  [ARM] 5490/1: ARM errata: Processor deadlock when a false hazard is created
  [ARM] 5487/1: ARM errata: Stale prediction on replaced interworking branch
  [ARM] 5488/1: ARM errata: Invalidation of the Instruction Cache operation can fail
  davinci: DM644x: NAND: update partitioning
  davinci: update DM644x support in preparation for more SoCs
  davinci: DM644x: rename board file
  davinci: update pin-multiplexing support
  davinci: serial: generalize for more SoCs
  davinci: DM355 IRQ Definitions
  davinci: DM646x: add interrupt number and priorities
  davinci: PSC: Clear bits in MDCTL reg before setting new bits
  davinci: gpio bugfixes
  davinci: add EDMA driver
  davinci: timers: use clk_get_rate()
  [ARM] pxa/littleton: add missing da9034 touchscreen support
  [ARM] pxa/zylonite: configure GPIO18/19 correctly, used by 2 GPIO expanders
  [ARM] pxa/zylonite: fix the issue of unused SDATA_IN_1 pin get AC97 not working
  [ARM] pxa: make ads7846 on corgi and spitz to sync on HSYNC
  [ARM] pxa: remove unused CPU_FREQ_PXA Kconfig symbol
  ...

* 'x86-mce-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-tip:
  x86, mce: fix boot logging logic
  x86, mce: make polling timer interval per CPU

* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6: (53 commits)
  [SCSI] libosd: OSD2r05: on-the-wire changes for latest OSD2 revision 5.
  [SCSI] libosd: OSD2r05: OSD_CRYPTO_KEYID_SIZE will grow 20 => 32 bytes
  [SCSI] libosd: OSD2r05: Prepare for rev5 attribute list changes
  [SCSI] libosd: fix potential ERR_PTR dereference in osd_initiator.c
  [SCSI] mpt2sas : bump driver version to 01.100.02.00
  [SCSI] mpt2sas: fix hotplug event processing
  [SCSI] mpt2sas : release diagnotic buffers prior host reset
  [SCSI] mpt2sas : Broadcast Primative AEN bug fix
  [SCSI] mpt2sas : Identify Dell series-7 adapters at driver load time
  [SCSI] mpt2sas : driver name needs to be in the MPT2IOCINFO ioctl
  [SCSI] mpt2sas : running out of message frames
  [SCSI] mpt2sas : fix oops when firmware sends large sense buffer size
  [SCSI] mpt2sas : the sanity check in base_interrupt needs to be on dword boundary
  [SCSI] mpt2sas : unique ioctl magic number
  [SCSI] fix sign extension with 1.5TB usb-storage LBD=y
  [SCSI] ipr: Fix sleeping function called with interrupts disabled
  [SCSI] fcoe: fip: add multicast filter to receive FIP advertisements.
  [SCSI] libfc: Fix compilation warnings with allmodconfig
  [SCSI] fcoe: fix spelling typos and bad comments
  [SCSI] fcoe: don't export functions that are internal to fcoe
  ...

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: document the multi-touch (MT) protocol
  Input: add detailed multi-touch finger data report protocol
  Input: allow certain EV_ABS events to bypass all filtering
  Input: bcm5974 - add documentation for the driver
  Input: bcm5974 - augment debug information
  Input: bcm5974 - Add support for the Macbook 5 (Unibody)
  Input: bcm5974 - add quad-finger tapping
  Input: bcm5974 - prepare for a new trackpad header type
  Input: appletouch - fix DMA to/from stack buffer
  Input: wacom - fix TabletPC touch bug
  Input: lifebook - add DMI entry for Fujitsu B-2130
  Input: ALPS - add signature for Toshiba Satellite Pro M10
  Input: elantech - make sure touchpad is really in absolute mode
  Input: elantech - provide a workaround for jumpy cursor on firmware 2.34
  Input: ucb1400 - use disable_irq_nosync() in irq handler
  Input: tsc2007 - use disable_irq_nosync() in irq handler
  Input: sa1111ps2 - use disable_irq_nosync() in irq handlers
  Input: omap-keypad - use disable_irq_nosync() in irq handler

See http://bugzilla.kernel.org/show_bug.cgi?id=13034

If the port gets into a TIME_WAIT state, then we cannot reconnect without
binding to a new port.
Tested-by: Petr Vandrovec <petr@vandrovec.name>
Tested-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-fixes:
  kbuild, modpost: Check the section flags, to catch missing "ax"/"aw"
  kbuild: fix comment in modpost.c
  kbuild: fix scripts/setlocalversion with git
  kbuild: fix Module.markers permission error under cygwin
  docs: also clean index.html
  kbuild: remove a tag file before it is regenerated
  kbuild: "make prepare" should be "make modules_prepare"
  kbuild: clean Module.markers and modules.order for out-of-tree modules
  avr32: drop unused CLEAN_FILES

* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2:
  ocfs2: Change repository in MAINTAINERS.
  ocfs2: Fix a missing credit when deleting from indexed directories.
  ocfs2/trivial: Remove unused variable in ocfs2_rename.
  ocfs2: Add missing iput() during error handling in ocfs2_dentry_attach_lock()
  ocfs2: Fix some printk() warnings.
  ocfs2: Fix 2 warning during ocfs2 make.
  ocfs2: Reserve 1 more cluster in expanding_inline_dir for indexed dir.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
  HID: fix oops in hid_check_keys_pressed()
  HID: fix possible deadlock in usbhid_close()
  HID: Fix the support for apple mini aluminium keyboard
  HID: Add support for the G25 force feedback wheel in native mode
  HID: hidraw -- fix missing unlocks in unlocked_ioctl

* 'for-linus' of git://www.linux-m32r.org/git/takata/linux-2.6_dev:
  m32r: use __stringify() macro in assembler.h
  m32r: build fix for __stringify macro

Fix the display of a few fields in the iBFT NIC attribute structure in
sysfs.

Ensure that, if the DHCP IP address and the subnet mask for the interface
is present in the iBFT NIC structure, the corresponding entries are
created in sysfs tree for the device.  This would hence create the
additional entries in the tree based on the iBFT table and would not
delete any existing entries.
Signed-off-by: Ashutosh Naik <ashutosh.naik@gmail.com>
Cc: Vishnu V <vishnu@chelsio.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Avoid setting less than two pages for vm_dirty_bytes: this is necessary to
avoid potential division by 0 (like the following) in get_dirty_limits().

[   49.951610] divide error: 0000 [#1] PREEMPT SMP
[   49.952195] last sysfs file: /sys/devices/pci0000:00/0000:00:01.1/host0/target0:0:0/0:0:0:0/block/sda/uevent
[   49.952195] CPU 1
[   49.952195] Modules linked in: pcspkr
[   49.952195] Pid: 3064, comm: dd Not tainted 2.6.30-rc3 #1
[   49.952195] RIP: 0010:[<ffffffff802d39a9>]  [<ffffffff802d39a9>] get_dirty_limits+0xe9/0x2c0
[   49.952195] RSP: 0018:ffff88001de03a98  EFLAGS: 00010202
[   49.952195] RAX: 00000000000000c0 RBX: ffff88001de03b80 RCX: 28f5c28f5c28f5c3
[   49.952195] RDX: 0000000000000000 RSI: 00000000000000c0 RDI: 0000000000000000
[   49.952195] RBP: ffff88001de03ae8 R08: 0000000000000000 R09: 0000000000000000
[   49.952195] R10: ffff88001ddda9a0 R11: 0000000000000001 R12: 0000000000000001
[   49.952195] R13: ffff88001fbc8218 R14: ffff88001de03b70 R15: ffff88001de03b78
[   49.952195] FS:  00007fe9a435b6f0(0000) GS:ffff8800025d9000(0000) knlGS:0000000000000000
[   49.952195] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   49.952195] CR2: 00007fe9a39ab000 CR3: 000000001de38000 CR4: 00000000000006e0
[   49.952195] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   49.952195] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[   49.952195] Process dd (pid: 3064, threadinfo ffff88001de02000, task ffff88001ddda250)
[   49.952195] Stack:
[   49.952195]  ffff88001fa0de00 ffff88001f2dbd70 ffff88001f9fe800 000080b900000000
[   49.952195]  00000000000000c0 ffff8800027a6100 0000000000000400 ffff88001fbc8218
[   49.952195]  0000000000000000 0000000000000600 ffff88001de03bb8 ffffffff802d3ed7
[   49.952195] Call Trace:
[   49.952195]  [<ffffffff802d3ed7>] balance_dirty_pages_ratelimited_nr+0x1d7/0x3f0
[   49.952195]  [<ffffffff80368f8e>] ? ext3_writeback_write_end+0x9e/0x120
[   49.952195]  [<ffffffff802cc7df>] generic_file_buffered_write+0x12f/0x330
[   49.952195]  [<ffffffff802cce8d>] __generic_file_aio_write_nolock+0x26d/0x460
[   49.952195]  [<ffffffff802cda32>] ? generic_file_aio_write+0x52/0xd0
[   49.952195]  [<ffffffff802cda49>] generic_file_aio_write+0x69/0xd0
[   49.952195]  [<ffffffff80365fa6>] ext3_file_write+0x26/0xc0
[   49.952195]  [<ffffffff803034d1>] do_sync_write+0xf1/0x140
[   49.952195]  [<ffffffff80290d1a>] ? get_lock_stats+0x2a/0x60
[   49.952195]  [<ffffffff80280730>] ? autoremove_wake_function+0x0/0x40
[   49.952195]  [<ffffffff8030411b>] vfs_write+0xcb/0x190
[   49.952195]  [<ffffffff803042d0>] sys_write+0x50/0x90
[   49.952195]  [<ffffffff8022ff6b>] system_call_fastpath+0x16/0x1b
[   49.952195] Code: 00 00 00 2b 05 09 1c 17 01 48 89 c6 49 0f af f4 48 c1 ee 02 48 89 f0 48 f7 e1 48 89 d6 31 d2 48 c1 ee 02 48 0f af 75 d0 48 89 f0 <48> f7 f7 41 8b 95 ac 01 00 00 48 89 c7 49 0f af d4 48 c1 ea 02
[   49.952195] RIP  [<ffffffff802d39a9>] get_dirty_limits+0xe9/0x2c0
[   49.952195]  RSP <ffff88001de03a98>
[   50.096523] ---[ end trace 008d7aa02f244d7b ]---
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Local variable `scan' can overflow on zones which are larger than

	(2G * 4k) / 100 = 80GB.

Making it 64-bit on 64-bit will fix that up.

Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

->real_parent is the parent. ->parent may be the tracer.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/kernel-doc can (incorrectly) delete struct members that are
surrounded by /* ...  */ <struct members> /* ...  */ if there is a /*
private: */ comment in there somewhere also.

Fix that by making the "/* private:" only allow whitespace between /* and
"private:", not anything/everything in the world.

This fixes some erroneous kernel-doc warnings that popped up while
processing include/linux/usb/composite.h.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The Committed_AS field can underflow in certain situations:

>         # while true; do cat /proc/meminfo  | grep _AS; sleep 1; done | uniq -c
>               1 Committed_AS: 18446744073709323392 kB
>              11 Committed_AS: 18446744073709455488 kB
>               6 Committed_AS:    35136 kB
>               5 Committed_AS: 18446744073709454400 kB
>               7 Committed_AS:    35904 kB
>               3 Committed_AS: 18446744073709453248 kB
>               2 Committed_AS:    34752 kB
>               9 Committed_AS: 18446744073709453248 kB
>               8 Committed_AS:    34752 kB
>               3 Committed_AS: 18446744073709320960 kB
>               7 Committed_AS: 18446744073709454080 kB
>               3 Committed_AS: 18446744073709320960 kB
>               5 Committed_AS: 18446744073709454080 kB
>               6 Committed_AS: 18446744073709320960 kB

Because NR_CPUS can be greater than 1000 and meminfo_proc_show() does
not check for underflow.

But NR_CPUS proportional isn't good calculation.  In general,
possibility of lock contention is proportional to the number of online
cpus, not theorical maximum cpus (NR_CPUS).

The current kernel has generic percpu-counter stuff.  using it is right
way.  it makes code simplify and percpu_counter_read_positive() don't
make underflow issue.
Reported-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Eric B Munson <ebmunson@us.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: <stable@kernel.org>		[All kernel versions]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Some drivers using of_register_platform_driver() wrapper break on sparc
because the wrapper isn't in the header file.  This patch moves it from
Microblaze and PowerPC implementations and makes it common code.

Fixes this sparc64 allmodconfig build error (at least):

drivers/leds/leds-gpio.c: In function `gpio_led_init':
drivers/leds/leds-gpio.c:295: error: implicit declaration of function `of_register_platform_driver'
drivers/leds/leds-gpio.c: In function `gpio_led_exit':
drivers/leds/leds-gpio.c:311: error: implicit declaration of function `of_unregister_platform_driver'
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This fixes the problem introduced by commit 3bfacef4 (get rid of
special-casing the /sbin/loader on alpha): osf/1 ecoff binary segfaults
when binfmt_aout built as module.  That happens because aout binary
handler gets on the top of the binfmt list due to late registration, and
kernel attempts to execute the binary without preparatory work that must
be done by binfmt_loader.

Fixed by changing the registration order of the default binfmt handlers
using list_add_tail() and introducing insert_binfmt() function which
places new handler on the top of the binfmt list.  This might be generally
useful for installing arch-specific frontends for default handlers or just
for overriding them.
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Richard Henderson <rth@twiddle.net
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Richard Henderson <rth@twiddle.net
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Exception fixups for sections other than .text (like one in futex_init())
break the natural ordering of fixup entries, so sorting is required.

Without that the result of the exception table search depends on phase of
the moon.
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Richard Henderson <rth@twiddle.net
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

These platforms got broken after u64 => 'long long' conversion.

Apparently that change was compile-tested with 'make allmodconfig', but it
doesn't include systems that depend on !ALPHA_LEGACY_START_ADDRESS.
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Richard Henderson <rth@twiddle.net
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Uwe Geuder noted that he gets random bitmaps on a text console if he tried
to type extended characters (like the e acute).  For him everything above
unicode 0xa0 was corrupted.

After some digging there seems to be a little culprit in vgacon since the
beginning of ages (well git).  The function vgacon_font_get will store the
number of characters correctly in font->charcount but then calls to
vgacon_do_font_op(..., 0, 0).  Which means only the lower 256 characters
are actually stored to the fontdata.  The rest is left untouched.  So the
next time that saved data is used, the garbled font appears.  This happens
on every switch between text consoles.

Addresses https://bugs.launchpad.net/ubuntu/+source/linux/+bug/355057Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Tested-by: Uwe Geuder <ubuntuLp-ugeuder@sneakemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Current mem_cgroup_shrink_usage() has two problems.

1. It doesn't call mem_cgroup_out_of_memory and doesn't update
   last_oom_jiffies, so pagefault_out_of_memory invokes global OOM.

2. Considering hierarchy, shrinking has to be done from the
   mem_over_limit, not from the memcg which the page would be charged to.

mem_cgroup_try_charge_swapin() does all of these things properly, so we
use it and call cancel_charge_swapin when it succeeded.

The name of "shrink_usage" is not appropriate for this behavior, so we
change it too.
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.cn>
Cc: Paul Menage <menage@google.com>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The intention of commit aae8679b
("pagemap: fix bug in add_to_pagemap, require aligned-length reads of
/proc/pid/pagemap") was to force reads of /proc/pid/pagemap to be a
multiple of 8 bytes, but now it allows to read 0 bytes, which actually
puts some data to user's buffer.  According to POSIX, if count is zero,
read() should return zero and has no other results.
Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com>
Cc: Thomas Tuttle <ttuttle@google.com>
Acked-by: Matt Mackall <mpm@selenic.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Change page_mkwrite to allow implementations to return with the page
locked, and also change it's callers (in page fault paths) to hold the
lock until the page is marked dirty.  This allows the filesystem to have
full control of page dirtying events coming from the VM.

Rather than simply hold the page locked over the page_mkwrite call, we
call page_mkwrite with the page unlocked and allow callers to return with
it locked, so filesystems can avoid LOR conditions with page lock.

The problem with the current scheme is this: a filesystem that wants to
associate some metadata with a page as long as the page is dirty, will
perform this manipulation in its ->page_mkwrite.  It currently then must
return with the page unlocked and may not hold any other locks (according
to existing page_mkwrite convention).

In this window, the VM could write out the page, clearing page-dirty.  The
filesystem has no good way to detect that a dirty pte is about to be
attached, so it will happily write out the page, at which point, the
filesystem may manipulate the metadata to reflect that the page is no
longer dirty.

It is not always possible to perform the required metadata manipulation in
->set_page_dirty, because that function cannot block or fail.  The
filesystem may need to allocate some data structure, for example.

And the VM cannot mark the pte dirty before page_mkwrite, because
page_mkwrite is allowed to fail, so we must not allow any window where the
page could be written to if page_mkwrite does fail.

This solution of holding the page locked over the 3 critical operations
(page_mkwrite, setting the pte dirty, and finally setting the page dirty)
closes out races nicely, preventing page cleaning for writeout being
initiated in that window.  This provides the filesystem with a strong
synchronisation against the VM here.

- Sage needs this race closed for ceph filesystem.
- Trond for NFS (http://bugzilla.kernel.org/show_bug.cgi?id=12913).
- I need it for fsblock.
- I suspect other filesystems may need it too (eg. btrfs).
- I have converted buffer.c to the new locking. Even simple block allocation
  under dirty pages might be susceptible to i_size changing under partial page
  at the end of file (we also have a buffer.c-side problem here, but it cannot
  be fixed properly without this patch).
- Other filesystems (eg. NFS, maybe btrfs) will need to change their
  page_mkwrite functions themselves.

[ This also moves page_mkwrite another step closer to fault, which should
  eventually allow page_mkwrite to be moved into ->fault, and thus avoiding a
  filesystem calldown and page lock/unlock cycle in __do_fault. ]

[akpm@linux-foundation.org: fix derefs of NULL ->mapping]
Cc: Sage Weil <sage@newdream.net>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>