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>

On a linux-next allyesconfig build:

kernel/trace/ring_buffer.c:1726:
	warning: passing argument 1 of 'atomic_cmpxchg' from incompatible pointer type
linux-next/arch/s390/include/asm/atomic.h:112:
	note: expected 'struct atomic_t *' but argument is of type 'struct atomic64_t *'

atomic_long_cmpxchg and atomic_long_xchg are incorrectly defined for 64
bit architectures.  They should be mapped to the atomic64_* variants.
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/serial/crisv10.c:4428: error: unknown field 'read_proc' specified in initializer

Commit 0f043a81 ("proc tty: remove struct
tty_operations::read_proc") removes the read_proc entry from struct
tty_operations.

Rework the proc handling in the CRISv10 serial driver to use proc_fops
instead.
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Mikael Starvik <starvik@axis.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add Roland and Oleg as formal ptrace maintainers, they've been doing the
job for a while.

Includes the file patterns requested by Joe.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This is a bugfix for commit 3c776e64
("memcg: charge swapcache to proper memcg").

Used bit of swapcache is solid under page lock, but considering
move_account, pc->mem_cgroup is not.

We need lock_page_cgroup() anyway.
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

I will finish school soon, so replace my student address with this one.
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fix an obvious incorrect return status in autofs4_mount_busy().
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

By the time the memory cgroup code is notified about a swapin we
already hold a reference on the fault page.

If the cgroup callback fails make sure to unlock AND release the page
reference which was taken by lookup_swap_cach(), or we leak the reference.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

acpi_rs_get_pci_routing_table_length is not performing sufficient
validation on the package returned from _PRT.  It assumes a package of
packages and fails/faults if this is not the case.

We should validate each subpackage when extracted from the parent
package, and not accept objects of the wrong type, since that will just
cause the scanning to fail (likely with a kernel oops).

This can only happen with a serious BIOS bug, and is accompanied by a
warning something like this:

  ACPI Warning (nspredef-0949): \_SB_.PCI0.PEG4._PRT: Return Package type mismatch at index 0 - found Integer, expected Package [20090320]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ecryptfs/ecryptfs-2.6:
  eCryptfs: Fix min function comparison warning
  ecryptfs: fix printk format warning

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6:
  V4L/DVB (11652): au0828: fix kernel oops regression on USB disconnect.
  V4L/DVB (11626): cx23885: Two fixes for DViCO FusionHDTV DVB-T Dual Express
  V4L/DVB (11612): mx3_camera: Fix compilation with CONFIG_PM
  V4L/DVB (11570): patch: s2255drv: fix race condition on set mode
  V4L/DVB (11568): cx18: Fix the handling of i2c bus registration error
  V4L/DVB (11561a): move media after i2c
  V4L/DVB (11516): drivers/media/video/saa5246a.c: fix use-after-free
  V4L/DVB (11515): drivers/media/video/saa5249.c: fix use-after-free and leak
  V4L/DVB (11494a): cx231xx Kconfig fixes
  V4L/DVB (11494): cx18: Send correct input routing value to external audio multiplexers

A regression was introduced in hg changeset 33810c734a0d, which resulted in
a kernel panic whenever the device was disconnected from USB.  The call to
4l2_device_register() was overwriting the pointer for usb_set_intfdata(), so
when au0828_usb_disconnect() was called, the usb_get_intfdata() returned a
pointer to the v4l2_device instead of the au0828_dev structure.
Signed-off-by: Devin Heitmueller <dheitmueller@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Two fixes for DViCO FusionHDTV DVB-T Dual Express:

 * Reset correct tuner when reinitializing xc3028.
 * Disable the I2C gate control to avoid locking up the I2C bus.
Tested-by: John Knops <jknops@australiaonline.net.au>
Reviewed-by: Steven Toth <stoth@linuxtv.org>
Signed-off-by: Christopher Pascoe <linuxdvb@itee.uq.edu.au>
Signed-off-by: Devin Heitmueller <dheitmueller@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

set_modeready flag must be set before command sent to USB in
s2255_write_config.
Signed-off-by: Dean Anderson <dean@sensoray.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

* Return actual error values as returned by the i2c subsystem, rather
  than 0 or 1.
* If the registration of the second bus fails, unregister the first one
  before exiting, otherwise we are leaking resources.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Currently drivers/media drivers are linked very early - directly after
base, block, misc, and mfd and before ata, scsi, ide, input, firewire,
usb, and i2c. This breaks static build of video4linux drivers, that use
generic CPU i2c adapter drivers and the v4l2-subdev subsystem, because
during video4linux probing the v4l2-subdev core requires a struct
i2c_adapter context, which cannot be satisfied before the i2c subsystem is
initialised. Moving drivers/media after drivers/i2c fixes this problem.

The best way to trigger action is by submitting a patch:-) So, let's see
what comes out of it - on the one hand I don't see any reason why media
has to be linked this early, and nobody was able to give me one yesterday
as this problem has been discussed on linux-media, OTOH, maybe indeed it
would be better to move i2c the whole way up above media, but that'd be
much bigger of a change, I think.
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.htmlSigned-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

I lowered the kfree(t) down a couple lines and removed the superflous
"t->vdev = NULL;"
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

I moved the kfree() down a couple lines.  t->vdev is going to be in freed
memory so there is no point setting it to NULL.  I added a kfree(t) on a
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

selecting ALSA module breaks if !SND. Just remove select.

While here, let's fix the whitespacing at the Kconfig.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

A late v4l2_subdev framework change accidentally sent the audio input
routing value to the external multiplexer, instead of the muxer input routing
value to the external multiplexer.  This change corrects that error.
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (24 commits)
  e100: do not go D3 in shutdown unless system is powering off
  netfilter: revised locking for x_tables
  Bluetooth: Fix connection establishment with low security requirement
  Bluetooth: Add different pairing timeout for Legacy Pairing
  Bluetooth: Ensure that HCI sysfs add/del is preempt safe
  net: Avoid extra wakeups of threads blocked in wait_for_packet()
  net: Fix typo in net_device_ops description.
  ipv4: Limit size of route cache hash table
  Add reference to CAPI 2.0 standard
  Documentation/isdn/INTERFACE.CAPI
  update Documentation/isdn/00-INDEX
  ixgbe: Fix WoL functionality for 82599 KX4 devices
  veth: prevent oops caused by netdev destructor
  xfrm: wrong hash value for temporary SA
  forcedeth: tx timeout fix
  net: Fix LL_MAX_HEADER for CONFIG_TR_MODULE
  mlx4_en: Handle page allocation failure during receive
  mlx4_en: Fix cleanup flow on cq activation
  vlan: update vlan carrier state for admin up/down
  netfilter: xt_recent: fix stack overread in compat code
  ...

After experimenting with kexec with the last merges after 2.6.29, I've
had some problems when probing e100.  It would not read the eeprom.  After
some bisects, I realized this has been like that since forever (at least
2.6.18).  The problem is that shutdown is doing the same thing that
suspend does and puts the device in D3 state.  I couldn't find a way to
get the device back to a sane state in the probe function.  So, based on
some similar patches from Rafael J. Wysocki for e1000, e1000e, and ixgbe,
I wrote this one for e100.
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The x_tables are organized with a table structure and a per-cpu copies
of the counters and rules. On older kernels there was a reader/writer 
lock per table which was a performance bottleneck. In 2.6.30-rc, this
was converted to use RCU and the counters/rules which solved the performance
problems for do_table but made replacing rules much slower because of
the necessary RCU grace period.

This version uses a per-cpu set of spinlocks and counters to allow to
table processing to proceed without the cache thrashing of a global
reader lock and keeps the same performance for table updates.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

* 'drm-intel-next' of git://git.kernel.org/pub/scm/linux/kernel/git/anholt/drm-intel:
  drm/i915: fix up error path leak in i915_cmdbuffer
  drm/i915: fix unpaired i915 device mutex on entervt failure.
  drm/i915: add support for G41 chipset
  drm/i915: Enable ASLE if present
  drm/i915: Unregister ACPI video driver when exiting
  drm/i915: Register ACPI video even when not modesetting
  drm/i915: fix transition to I915_TILING_NONE
  drm/i915: Don't let an oops get triggered from irq_emit without dma init.
  drm/i915: allow tiled front buffers on 965+

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband: (21 commits)
  RDMA/nes: Update iw_nes version
  RDMA/nes: Fix error path in nes_accept()
  RDMA/nes: Fix hang issues for large cluster dynamic connections
  RDMA/nes: Increase rexmit timeout interval
  RDMA/nes: Check for sequence number wrap-around
  RDMA/nes: Do not set apbvt entry for loopback
  RDMA/nes: Fix unused variable compile warning when INFINIBAND_NES_DEBUG=n
  RDMA/nes: Fix fw_ver in /sys
  RDMA/nes: Set trace length to 1 inch for SFP_D
  RDMA/nes: Enable repause timer for port 1
  RDMA/nes: Correct CDR loop filter setting for port 1
  RDMA/nes: Modify thermo mitigation to flip SerDes1 ref clk to internal
  RDMA/nes: Fix resource issues in nes_create_cq() and nes_destroy_cq()
  RDMA/nes: Remove root_256()'s unused pbl_count_256 parameter
  mlx4_core: Fix memory leak in mlx4_enable_msi_x()
  IB/mthca: Fix timeout for INIT_HCA and a few other commands
  RDMA/cxgb3: Don't zero QP attrs when moving to IDLE
  RDMA/nes: Fix bugs in nes_reg_phys_mr()
  RDMA/nes: Fix compiler warning at nes_verbs.c:1955
  IPoIB: Disable NAPI while CQ is being drained
  ...

Fix this:

  arch/m68k/kernel/sun3-head.S: Assembler messages:
  arch/m68k/kernel/sun3-head.S:32: Error: Unknown operator -- statement `__head' ignored

Introduced by commit 6f335cab ("m68k:
convert to use __HEAD and HEAD_TEXT macros."), which started using
__HEAD without adding the appropriate include.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  bio: fix memcpy corruption in bio_copy_user_iov()
  hd: fix locking
  mg_disk: fix CONFIG_LBD=y warning
  mg_disk: fix locking

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lrg/voltage-2.6:
  regulator: Fix default constraints for fixed voltage regulators
  regulator/bq24022: fix bug in is_enabled function
  regulator/virtual: fix strings compare predicates
  regulator core: fix double-free in regulator_register() error path
  drivers/regulator: fix when type is different from REGULATOR_VOLTAGE or REGULATOR_CURRENT
  unreachable code in drms_uA_update()
  regulator: fix header file missing kernel-doc

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc:
  powerpc/ps3: Fix build error on UP
  powerpc/cell: Select PCI for IBM_CELL_BLADE AND CELLEB
  powerpc: ppc32 needs elf_read_implies_exec()
  powerpc/86xx: Add device_type entry to soc for ppc9a
  powerpc/44x: Correct memory size calculation for denali-based boards
  maintainers: Fix PowerPC 4xx git tree
  powerpc: fix for long standing bug noticed by gcc 4.4.0
  Revert "powerpc: Add support for early tlbilx opcode"

Commit edada399 broke the build on 64-bit powerpc because it moved the
__ftr_alt_* sections of a file away from the .text section, causing
link failures due to relative conditional branch targets being too far
away from the branch instructions.  This happens on pretty much all
64-bit powerpc configs.

This change reverts commit edada399 while preserving the update from
the *.refok sections to .ref.text that has happened since.
Signed-off-by: Tim Abbott <tabbott@mit.edu>
Requested-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

st driver uses blk_rq_map_user() in order to just build a request out
of page frames. In this case, map_data->offset is a non zero value and
iov[0].iov_base is NULL. We need to increase nr_pages for that.

Cc: stable@kernel.org
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

hd dance around local irq and HD_IRQ enable without achieving much.
It ends up transferring data from irq handler with both local irq and
HD_IRQ disabled.  The only place it actually does something is while
transferring the first block of a request which it does with HD_IRQ
disabled but local irq enabled.

Unfortunately, the dancing is horribly broken from locking POV.  IRQ
and timeout handlers access block queue without grabbing the queue
lock and running the driver in SMP configuration crashes the whole
machine pretty quickly.

Remove meaningless irq enable/disable dancing and add proper locking
in issue, irq and timeout paths.
Signed-off-by: Tejun Heo <tj@kernel.org>

drivers/block/mg_disk.c: In function ‘mg_dump_status’:
drivers/block/mg_disk.c:265: warning: format ‘%ld’ expects type ‘long int’, but
argument 2 has type ‘sector_t’

[ Impact: kill build warning ]

Cc: unsik Kim <donari75@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

IRQ and timeout handlers call functions which expect locked queue lock
without locking it.  Fix it.

While at it, convert 0s used as null pointer constant to NULLs.

[ Impact: fix locking, cleanup ]
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: unsik Kim <donari75@gmail.com>

Default voltage constraints were being provided for fixed voltage
regulator where board constraints were not provided but these constraints
used INT_MIN as the default minimum voltage which is not a valid value
since it is less than zero. Use 1uV instead.

Also set the default values we set in the constraints themselves since
otherwise the max_uV constraint we determine will not be stored in the
actual constraint strucutre and will therefore not be used.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

This seems to be fallout from last October's regulator core rework.
It got noticed only because of recent regulator framework changes.
Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>