/proc/diskstats would display a strange output as follows.

$ cat /proc/diskstats |grep sda
   8       0 sda 90524 7579 102154 20464 0 0 0 0 0 14096 20089
   8       1 sda1 19085 1352 21841 4209 0 0 0 0 4294967064 15689 4293424691
                                                ~~~~~~~~~~
   8       2 sda2 71252 3624 74891 15950 0 0 0 0 232 23995 1562390
   8       3 sda3 54 487 2188 92 0 0 0 0 0 88 92
   8       4 sda4 4 0 8 0 0 0 0 0 0 0 0
   8       5 sda5 81 2027 2130 138 0 0 0 0 0 87 137

Its reason is the wrong way of accounting hd_struct->in_flight. When a bio is
merged into a request belongs to different partition by ELEVATOR_FRONT_MERGE.

The detailed root cause is as follows.

Assuming that there are two partition, sda1 and sda2.

1. A request for sda2 is in request_queue. Hence sda1's hd_struct->in_flight
   is 0 and sda2's one is 1.

        | hd_struct->in_flight
   ---------------------------
   sda1 |          0
   sda2 |          1
   ---------------------------

2. A bio belongs to sda1 is issued and is merged into the request mentioned on
   step1 by ELEVATOR_BACK_MERGE. The first sector of the request is changed
   from sda2 region to sda1 region. However the two partition's
   hd_struct->in_flight are not changed.

        | hd_struct->in_flight
   ---------------------------
   sda1 |          0
   sda2 |          1
   ---------------------------

3. The request is finished and blk_account_io_done() is called. In this case,
   sda2's hd_struct->in_flight, not a sda1's one, is decremented.

        | hd_struct->in_flight
   ---------------------------
   sda1 |         -1
   sda2 |          1
   ---------------------------

The patch fixes the problem by caching the partition lookup
inside the request structure, hence making sure that the increment
and decrement will always happen on the same partition struct. This
also speeds up IO with accounting enabled, since it cuts down on
the number of lookups we have to do.

Also add a refcount to struct hd_struct to keep the partition in
memory as long as users exist. We use kref_test_and_get() to ensure
we don't add a reference to a partition which is going away.
Signed-off-by: NJerome Marchand <jmarchan@redhat.com>
Signed-off-by: NYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: stable@kernel.org
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Add kref_test_and_get() function, which atomically add a reference only if
refcount is not zero. This prevent to add a reference to an object that is
already being removed.
Signed-off-by: NJerome Marchand <jmarchan@redhat.com>
Cc: stable@kernel.org
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Work items processed by kintegrityd_wq won't block much, may burn a
lot of CPU cycles and affect IO latency.  Use alloc_workqueue() to
mark it highpri and CPU intensive with max concurrency of 1.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

kblockd is used for unplugging and may affect IO latency and
throughput and the max number of concurrent work items are bound by
the number of block devices.  Make it HIGHPRI workqueue w/ default max
concurrency.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

This patch fixes a spelling error in a source code comment and removes
superfluous braces in the function exit_io_context().
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Cc: Jens Axboe <jaxboe@fusionio.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Commit a8adbe37 forgot to remove the return variable, kill it.

drivers/block/loop.c: In function 'lo_splice_actor':
drivers/block/loop.c:398: warning: unused variable 'ret'
[...]
fs/nfsd/vfs.c: In function 'nfsd_splice_actor':
fs/nfsd/vfs.c:848: warning: unused variable 'ret'
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

The major/minor device numbers are always defined and used as `unsigned'.
Signed-off-by: NYang Zhang <kthreadd@gmail.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Signed-off-by: NYang Zhang <kthreadd@gmail.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

When cfq_choose_cfqg() is called in select_queue(), there must be at least one
backlogged CFQ queue waiting for dispatching, hence there must be at least one
backlogged CFQ group on service tree. So we never call choose_service_tree()
with cfqg == NULL.
Signed-off-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com>
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

This patch pulls calls to buf->ops->confirm() from all actors passed
(also indirectly) to splice_from_pipe_feed().

Is avoiding the call to buf->ops->confirm() while splice()ing to
/dev/null is an intentional optimization? No other user does that
and this will remove this special case.

Against current linux.git 6313e3c2.
Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

If priority is changed, continuing to check workload_expires and service tree
count of the previous workload does not make sense. We should always choose
the workload with lowest key of new priority in such case.
Signed-off-by: NShaohua Li <shaohua.li@intel.com>
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

It's able to check whether a CFQ group on a service tree by
checking "cfqg->rb_node". There's no need to maintain an
extra flag here.
Signed-off-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

When a cfq group is running, it won't be dequeued from service tree, so
there's no need to store the active one in st->active. Just gid rid of it.
Signed-off-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Merge branch 'cleanup-bd_claim' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into for-2.6.38/core

Signed-off-by: NKiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

The addition of CONFIG_SECURITY_DMESG_RESTRICT resulted in a build
failure when CONFIG_PRINTK=n.  This is because the capabilities code
which used the new option was built even though the variable in question
didn't exist.

The patch here fixes this by moving the capabilities checks out of the
LSM and into the caller.  All (known) LSMs should have been calling the
capabilities hook already so it actually makes the code organization
better to eliminate the hook altogether.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NJames Morris <jmorris@namei.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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

* 'omap-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6:
  arm: omap1: devices: need to return with a value
  OMAP1: camera.h: add missing include
  omap: dma: Add read-back to DMA interrupt handler to avoid spuriousinterrupts
  OMAP2: Devkit8000: Fix mmc regulator failure

* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
  hwmon: (w83795) Check for BEEP pin availability
  hwmon: (w83795) Clear intrusion alarm immediately
  hwmon: (w83795) Read the intrusion state properly
  hwmon: (w83795) Print the actual temperature channels as sources
  hwmon: (w83795) List all usable temperature sources
  hwmon: (w83795) Expose fan control method
  hwmon: (w83795) Fix fan control mode attributes
  hwmon: (lm95241) Check validity of input values
  hwmon: Change mail address of Hans J. Koch

* 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
  i2c: Sanity checks on adapter registration
  i2c: Mark i2c_adapter.id as deprecated
  i2c: Drivers shouldn't include <linux/i2c-id.h>
  i2c: Delete unused adapter IDs
  i2c: Remove obsolete cleanup for clientdata

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
  PCI: sysfs: fix printk warnings
  PCI: fix pci_bus_alloc_resource() hang, prefer positive decode
  PCI: read current power state at enable time
  PCI: fix size checks for mmap() on /proc/bus/pci files
  x86/PCI: coalesce overlapping host bridge windows
  PCI hotplug: ibmphp: Add check to prevent reading beyond mapped area

Make sure I2C adapters being registered have the required struct
fields set. If they don't, problems will happen later.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

It's about time to make it clear that i2c_adapter.id is deprecated.
Hopefully this will remind the last user to move over to a different
strategy.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NJarod Wilson <jarod@redhat.com>
Acked-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: NHans Verkuil <hverkuil@xs4all.nl>

Drivers don't need to include <linux/i2c-id.h>, especially not when
they don't use anything that header file provides.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Cc: Michael Hunold <michael@mihu.de>
Acked-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Delete unused I2C adapter IDs. Special cases are:

* I2C_HW_B_RIVA was still set in driver rivafb, however no other
  driver is ever looking for this value, so we can safely remove it.
* I2C_HW_B_HDPVR is used in staging driver lirc_zilog, however no
  adapter ID is ever set to this value, so the code in question never
  runs. As the code additionally expects that I2C_HW_B_HDPVR may not
  be defined, we can delete it now and let the lirc_zilog driver
  maintainer rewrite this piece of code.

Big thanks for Hans Verkuil for doing all the hard work :)
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NJarod Wilson <jarod@redhat.com>
Acked-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: NHans Verkuil <hverkuil@xs4all.nl>

A few new i2c-drivers came into the kernel which clear the clientdata-pointer
on exit. This is obsolete meanwhile, so fix it and hope the word will spread.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Acked-by: NAlan Cox <alan@linux.intel.com>
Acked-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Move the logging bits from kernel.h into printk.h so that
there is a bit more logical separation of the generic from
the printk logging specific parts.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The fix in commit 6b4e81db ("i8k: Tell gcc that *regs gets
clobbered") to work around the gcc miscompiling i8k.c to add "+m
(*regs)" caused register pressure problems and a build failure.

Changing the 'asm' statement to 'asm volatile' instead should prevent
that and works around the gcc bug as well, so we can remove the "+m".

[ Background on the gcc bug: a memory clobber fails to mark the function
  the asm resides in as non-pure (aka "__attribute__((const))"), so if
  the function does nothing else that triggers the non-pure logic, gcc
  will think that that function has no side effects at all. As a result,
  callers will be mis-compiled.

  Adding the "+m" made gcc see that it's not a pure function, and so
  does "asm volatile". The problem was never really the need to mark
  "*regs" as changed, since the memory clobber did that part - the
  problem was just a bug in the gcc "pure" function analysis  - Linus ]
Signed-off-by: NJim Bos <jim876@xs4all.nl>
Acked-by: NJakub Jelinek <jakub@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On the W83795ADG, there's a single pin for BEEP and OVT#, so you
can't have both. Check the configuration and don't create beep
attributes when BEEP pin is not available.

The W83795G has a dedicated BEEP pin so the functionality is always
available there.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NGuenter Roeck <guenter.roeck@ericsson.com>

When asked to clear the intrusion alarm, do so immediately. We have to
invalidate the cache to make sure the new status will be read. But we
also have to read from the status register once to clear the pending
alarm, as writing to CLR_CHS surprising won't clear it automatically.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NGuenter Roeck <guenter.roeck@ericsson.com>

We can't read the intrusion state from the real-time alarm registers
as we do for all other alarm flags, because real-time alarm bits don't
stick (by definition) and the intrusion state has to stick until
explicitly cleared (otherwise it has little value.)

So we have to use the interrupt status register instead, which is read
from the same address but with a configuration bit flipped in another
register.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NGuenter Roeck <guenter.roeck@ericsson.com>

Don't expose raw register values to user-space. Decode and encode
temperature channels selected as temperature sources as needed.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NGuenter Roeck <guenter.roeck@ericsson.com>

Temperature sources are not correlated directly with temperature
channels. A look-up table is required to find out which temperature
sources can be used depending on which temperature channels (both
analog and digital) are enabled.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NGuenter Roeck <guenter.roeck@ericsson.com>

Expose fan control method (DC vs. PWM) using the standard sysfs
attributes. I've made it read-only as the board should be wired for
a given mode, the BIOS should have set up the chip for this mode, and
you shouldn't have to change it. But it would be easy enough to make
it changeable if someone comes up with a use case.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NGuenter Roeck <guenter.roeck@ericsson.com>

There were two bugs:
* Speed cruise mode was improperly reported for all fans but fan1.
* Fan control method (PWM vs. DC) was mixed with the control mode.
  It will be added back as a separate attribute, as per the standard
  sysfs interface.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NGuenter Roeck <guenter.roeck@ericsson.com>

This clears the following build-time warnings I was seeing:

drivers/hwmon/lm95241.c: In function "set_interval":
drivers/hwmon/lm95241.c:132:15: warning: ignoring return value of "strict_strtol", declared with attribute warn_unused_result
drivers/hwmon/lm95241.c: In function "set_max2":
drivers/hwmon/lm95241.c:278:1: warning: ignoring return value of "strict_strtol", declared with attribute warn_unused_result
drivers/hwmon/lm95241.c: In function "set_max1":
drivers/hwmon/lm95241.c:277:1: warning: ignoring return value of "strict_strtol", declared with attribute warn_unused_result
drivers/hwmon/lm95241.c: In function "set_min2":
drivers/hwmon/lm95241.c:249:1: warning: ignoring return value of "strict_strtol", declared with attribute warn_unused_result
drivers/hwmon/lm95241.c: In function "set_min1":
drivers/hwmon/lm95241.c:248:1: warning: ignoring return value of "strict_strtol", declared with attribute warn_unused_result
drivers/hwmon/lm95241.c: In function "set_type2":
drivers/hwmon/lm95241.c:220:1: warning: ignoring return value of "strict_strtol", declared with attribute warn_unused_result
drivers/hwmon/lm95241.c: In function "set_type1":
drivers/hwmon/lm95241.c:219:1: warning: ignoring return value of "strict_strtol", declared with attribute warn_unused_result

This also fixes a small race in set_interval() as a side effect: by
working with a temporary local variable we prevent data->interval from
being accessed at a time it contains the interval value in the wrong
unit.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Cc: Davide Rizzo <elpa.rizzo@gmail.com>

My old mail address doesn't exist anymore. This changes all occurrences
to my new address.
Signed-off-by: NHans J. Koch <hjk@hansjkoch.de>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

o Allow hierarchical cgroup creation for blkio controller

o Currently we disallow it as both the io controller policies (throttling
  as well as proportion bandwidth) do not support hierarhical accounting
  and control. But the flip side is that blkio controller can not be used with
  libvirt as libvirt creates a cgroup hierarchy deeper than 1 level.

  <top-level-cgroup-dir>/<controller>/libvirt/qemu/<virtual-machine-groups>

o So this patch will allow creation of cgroup hierarhcy but at the backend
  everything will be treated as flat. So if somebody created a an hierarchy
  like as follows.

			root
			/  \
		     test1 test2
			|
		     test3

  CFQ and throttling will practically treat all groups at same level.

				pivot
			     /  |   \  \
			root  test1 test2  test3

o Once we have actual support for hierarchical accounting and control
  then we can introduce another cgroup tunable file "blkio.use_hierarchy"
  which will be 0 by default but if user wants to enforce hierarhical
  control then it can be set to 1. This way there should not be any
  ABI problems down the line.

o The only not so pretty part is introduction of extra file "use_hierarchy"
  down the line. Kame-san had mentioned that hierarhical accounting is
  expensive in memory controller hence they keep it off by default. I
  suspect same will be the case for IO controller also as for each IO
  completion we shall have to account IO through hierarchy up to the root.
  if yes, then it probably is not a very bad idea to introduce this extra
  file so that it will be used only when somebody needs it and some people
  might enable hierarchy only in part of the hierarchy.

o This is how basically memory controller also uses "use_hierarhcy" and
  they also allowed creation of hierarchies when actual backend support
  was not available.
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
Acked-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Reviewed-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com>
Reviewed-by: NCiju Rajan K <ciju@linux.vnet.ibm.com>
Tested-by: NCiju Rajan K <ciju@linux.vnet.ibm.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>