overlay_info struct, used to configure overlays, currently includes both
physical and virtual addresses for the pixels. The vaddr was added to
support more exotic configurations where CPU would be used to update a
display, but it is not currently used and there has been no interest in
the feature. Using CPU to update a screen is also less interesting now
that OMAP4 has two LCD outputs.

This patch removes the vaddr field, and modifies the users of omapdss
accordingly. This makes the use of omapdss a bit simpler, as the user
doesn't need to think if it needs to give the vaddr.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

This is a driver for N800's display, ported from the old omapfb. This is
a slightly lighter version of the driver as not all features of the old
driver can be ported without big changes to DSS2, and also because some
of the HW features used in the old driver are unclear (e.g. the power
management part).

That said, the new driver works fine for basic use.

Architecturally the driver is not as neat as it could be. N800's display
HW consists of a display buffer chip and a panel, and ideally they would
be represented by separate, independent drivers. This is not currently
possible, and this driver contains both buffer chip and panel driver.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Taal panel driver supports two kinds of backlight control: 1) using DSI
commands sent to the panel to control the backlight, 2) calling function
pointers going to the board file to control the backlight.

The second option is a bit hacky, and will no longer be needed when the
PWM driver supports the backlight features. After that we can use the
standard PWM backlight driver.

This patch removes the second backlight control mechanism, and adds a
boolean field, use_dsi_backlight, to nokia_dsi_panel_data which the
board file can use to inform whether the panel driver should use DSI
commands to control the backlight.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

We have currently panel-generic-dpi driver, which is a combined driver
for dummy panels and also for DVI output.

The aim is to split the panel-generic-dpi into two, one for fixed size
dummy panels connected via DPI, and the other (this) for variable
resolution output which supports DDC channel (in practice a DVI framer
chip connected to DPI output).

Original i2c code by: Ricardo Salveti de Araujo
<ricardo.salveti@canonical.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

detect() can be used to probe if the display is connected.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

read_edid() can be used to get the EDID information from the display.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Add IRQ definitions for missing OMAP4 IRQs: FRAMEDONEWB, FRAMEDONETV,
WBBUFFEROVERFLOW.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

regn divider is one greater than the REGN divider in TRM. Add a comment
to point this out.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

regn divider is currently programmed to the registers without change,
but when calculating clock frequencies it is used as regn+1.

To make this similar to how DSI handles the dividers this patch changes
the regn value to be used as such for calculations, but the value
programmed to registers is regn-1.

This simplifies the clock frequency calculations, makes it similar to
DSI, and also allows us to use regn value 0 as undefined.

Cc: Mythri P K <mythripk@ti.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Add initial support for DSI video mode panels:
- Add a new structure omap_dss_dsi_videomode_data in the member "panel" in
  omap_dss_device struct. This allows panel driver to configure dsi video_mode
  specific parameters.
- Configure basic DSI video mode timing parameters: HBP, HFP, HSA, VBP, VFP, VSA,
  TL and VACT.
- Configure DSI protocol engine registers for video_mode support.
- Introduce functions dsi_video_mode_enable() and dsi_video_mode_disable() which
  enable/disable video mode for a given virtual channel and a given pixel format
  type.

Things left for later
- Add functions to check for errors in video mode timings provided by panel.
- Configure timing registers required  for command mode interleaving.
Signed-off-by: NArchit Taneja <archit@ti.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Currently, DSI pixel info is only represented by the pixel size in bits using
the pixel_size parameter in omap_dss_device struct's ctrl member.

This is not sufficient information for DSI video mode usage, as two of the
supported formats(RGB666 loosely packed, and RGB888) have the same pixel
container size, but different data_type values for the video mode packet header.

Create enum "omap_dss_dsi_pixel_format" which describes the pixel data format
the panel is configured for. Create helper function dsi_get_pixel_size() which
returns the pixel size of the given pixel format.

Modify functions omapdss_default_get_recommended_bpp() and dss_use_replication()
to use dsi_get_pixel_size().
Signed-off-by: NArchit Taneja <archit@ti.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Introduce read functions which use generic Processor-to-Peripheral
transaction types. These are needed by some devices which may not support
corresponding DCS commands.

Add function dsi_vc_generic_send_read_request() which can send
a short packet with 0, 1 or 2 bytes of request data and the corresponding
generic data type.

Rename function dsi_vc_dcs_read_rx_fifo() to dsi_vc_read_rx_fifo() and modify
it to take the enum "dss_dsi_content_type" as an argument to use either DCS
or GENERIC Peripheral-to-Processor transaction types while parsing data read
from the device.
Signed-off-by: NArchit Taneja <archit@ti.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Remove functions dsi_vc_dcs_read_1() and dsi_vc_dcs_read_2(), these are used
when the panel is expected to return 1 and 2 bytes respecitvely. This was manily
used for debugging purposes. These functions should be implemented in the panel
driver if needed.
Signed-off-by: NArchit Taneja <archit@ti.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Intoduce enum "dss_dsi_content_type" to differentiate between DCS and generic
content types.

Introduce short and long packet write functions which use generic
Processor-to-Peripheral transaction types. These are needed by some devices
which may not support corresponding DCS commands. Create common write functions
which allow code reuse between DCS and generic write functions.
Signed-off-by: NArchit Taneja <archit@ti.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Create an enum for DSI operation modes, use this to set the capabilities of the
device in dsi_init_display().
Signed-off-by: NArchit Taneja <archit@ti.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Add OMAP_DSS_OVL_CAP_GLOBAL_ALPHA and OMAP_DSS_OVL_CAP_PRE_MULT_ALPHA to
overlay capabilities. Use these instead of FEAT_GLOBAL_ALPHA,
FEAT_GLOBAL_ALPHA_VID1 and FEAT_PRE_MULT_ALPHA in code.

Remove FEAT_GLOBAL_ALPHA_VID1 and FEAT_PRE_MULT_ALPHA which are no
longer used. FEAT_GLOBAL_ALPHA is still used to decide if the HW has
global alpha register.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: NArchit Taneja <archit@ti.com>

Remove support for non-DISPC overlays and overlay managers.

The support to possibly have non-DISPC overlays and managers was made to
make it possible to use CPU and/or sDMA to update RFBI or DSI command
mode displays. It is ok to remove the support, because:

- No one has used the feature.
- Display update without DISPC is very slow, so it is debatable if the
  update would even be usable.
- Removal cleans up code.
- If such a feature is needed later, it is better implemented outside
  omapdss driver.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: NArchit Taneja <archit@ti.com>

Currently when changing the manager of an overlay, set_manager() directly
calls dispc to set the overlay's destination.

Change this to be more in line with other overlay configurations, and
this will also remove the need to have dispc clocks enabled when calling
set_manager().

A new field is added to overlay struct, "manager_changed". This is
similar to "display_changed" field in manager struct, and is used to
inform apply that the manager has changed and thus write to the
registers is needed.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

dsi_mux_pads() needs to know about the DSI HW module and the DSI lanes
used. Split the function into two, enable and disable, which take
necessary arguments, and add empty implementations for both.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

PicoDLP is a micro projector from TI.

DLP used in OMAP4 is dpp2600 (DLP Pico Projector) The DLP requires
commands to be sent over i2c for configurations. To know more about
dpp2600 commands please visit:
https://focus.ti.com/myti/docs/extranet.tsp?sectionId=403

The picodlp module consists of a dss driver and an i2c_client.

To know more please visit:
http://www.omappedia.org/wiki/PicoDLP_projector_guide

Based on original design from Mythri P K <mythripk@ti.com>
Signed-off-by: NMayuresh Janorkar <mayur@ti.com>
Signed-off-by: NMythri P K <mythripk@ti.com>
[tomi.valkeinen@ti.com: squashed commits]
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Fix kernel-doc warning about internal/private data by marking it
as "private:" so that kernel-doc will ignore it.

  Warning(include/linux/regulator/consumer.h:128): No description found for parameter 'ret'
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Acked-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix kernel-doc warning in net/cfg80211.h:

  Warning(include/net/cfg80211.h:1884): No description found for parameter 'registered'
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NJim Garlick <garlick@llnl.gov>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Some of the flags are OS/arch dependent we add a 9p
protocol value which maps to asm-generic/fcntl.h values in Linux
Based on the original patch from Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

The current cgroup context switch code was incorrect leading
to bogus counts. Furthermore, as soon as there was an active
cgroup event on a CPU, the context switch cost on that CPU
would increase by a significant amount as demonstrated by a
simple ping/pong example:

 $ ./pong
 Both processes pinned to CPU1, running for 10s
 10684.51 ctxsw/s

Now start a cgroup perf stat:
 $ perf stat -e cycles,cycles -A -a -G test  -C 1 -- sleep 100

$ ./pong
 Both processes pinned to CPU1, running for 10s
 6674.61 ctxsw/s

That's a 37% penalty.

Note that pong is not even in the monitored cgroup.

The results shown by perf stat are bogus:
 $ perf stat -e cycles,cycles -A -a -G test  -C 1 -- sleep 100

 Performance counter stats for 'sleep 100':

 CPU1 <not counted> cycles   test
 CPU1 16,984,189,138 cycles  #    0.000 GHz

The second 'cycles' event should report a count @ CPU clock
(here 2.4GHz) as it is counting across all cgroups.

The patch below fixes the bogus accounting and bypasses any
cgroup switches in case the outgoing and incoming tasks are
in the same cgroup.

With this patch the same test now yields:
 $ ./pong
 Both processes pinned to CPU1, running for 10s
 10775.30 ctxsw/s

Start perf stat with cgroup:

 $ perf stat -e cycles,cycles -A -a -G test  -C 1 -- sleep 10

Run pong outside the cgroup:
 $ /pong
 Both processes pinned to CPU1, running for 10s
 10687.80 ctxsw/s

The penalty is now less than 2%.

And the results for perf stat are correct:

$ perf stat -e cycles,cycles -A -a -G test  -C 1 -- sleep 10

 Performance counter stats for 'sleep 10':

 CPU1 <not counted> cycles test #    0.000 GHz
 CPU1 23,933,981,448 cycles      #    0.000 GHz

Now perf stat reports the correct counts for
for the non cgroup event.

If we run pong inside the cgroup, then we also get the
correct counts:

$ perf stat -e cycles,cycles -A -a -G test  -C 1 -- sleep 10

 Performance counter stats for 'sleep 10':

 CPU1 22,297,726,205 cycles test #    0.000 GHz
 CPU1 23,933,981,448 cycles      #    0.000 GHz

      10.001457237 seconds time elapsed
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110825135803.GA4697@quadSigned-off-by: NIngo Molnar <mingo@elte.hu>

The nfsservctl system call is now gone, so we should remove all
linkage for it.
Signed-off-by: NNeilBrown <neilb@suse.de>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We need a callback to do some things after pwm_enable, pwm_disable
and pwm_config.
Signed-off-by: NDilan Lee <dilee@nvidia.com>
Reviewed-by: NRobert Morell <rmorell@nvidia.com>
Reviewed-by: NArun Murthy <arun.murthy@stericsson.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Replace/remove use of RIO v.1.2 registers/bits that are not
forward-compatible with newer versions of RapidIO specification.

RapidIO specification v.1.3 removed Write Port CSR, Doorbell CSR,
Mailbox CSR and Mailbox and Doorbell bits of the PEF CAR.

Use of removed (since RIO v.1.3) register bits affects users of
currently available 1.3 and 2.x compliant devices who may use not so
recent kernel versions.

Removing checks for unsupported bits makes corresponding routines
compatible with all versions of RapidIO specification.  Therefore,
backporting makes stable kernel versions compliant with RIO v.1.3 and
later as well.
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Thomas Moll <thomas.moll@sysgo.com>
Cc: Chul Kim <chul.kim@idt.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NEvgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Purely in-memory filesystems do not use the inode hash as the dcache
tells us if an entry already exists.  As a result, they do not call
unlock_new_inode, and thus directory inodes do not get put into a
different lockdep class for i_sem.

We need the different lockdep classes, because the locking order for
i_mutex is different for directory inodes and regular inodes.  Directory
inodes can do "readdir()", which takes i_mutex *before* possibly taking
mm->mmap_sem (due to a page fault while copying the directory entry to
user space).

In contrast, regular inodes can be mmap'ed, which takes mm->mmap_sem
before accessing i_mutex.

The two cases can never happen for the same inode, so no real deadlock
can occur, but without the different lockdep classes, lockdep cannot
understand that.  As a result, if CONFIG_DEBUG_LOCK_ALLOC is set, this
can lead to false positives from lockdep like below:

    find/645 is trying to acquire lock:
     (&mm->mmap_sem){++++++}, at: [<ffffffff81109514>] might_fault+0x5c/0xac

    but task is already holding lock:
     (&sb->s_type->i_mutex_key#15){+.+.+.}, at: [<ffffffff81149f34>]
    vfs_readdir+0x5b/0xb4

    which lock already depends on the new lock.

    the existing dependency chain (in reverse order) is:

    -> #1 (&sb->s_type->i_mutex_key#15){+.+.+.}:
          [<ffffffff8108ac26>] lock_acquire+0xbf/0x103
          [<ffffffff814db822>] __mutex_lock_common+0x4c/0x361
          [<ffffffff814dbc46>] mutex_lock_nested+0x40/0x45
          [<ffffffff811daa87>] hugetlbfs_file_mmap+0x82/0x110
          [<ffffffff81111557>] mmap_region+0x258/0x432
          [<ffffffff811119dd>] do_mmap_pgoff+0x2ac/0x306
          [<ffffffff81111b4f>] sys_mmap_pgoff+0x118/0x16a
          [<ffffffff8100c858>] sys_mmap+0x22/0x24
          [<ffffffff814e3ec2>] system_call_fastpath+0x16/0x1b

    -> #0 (&mm->mmap_sem){++++++}:
          [<ffffffff8108a4bc>] __lock_acquire+0xa1a/0xcf7
          [<ffffffff8108ac26>] lock_acquire+0xbf/0x103
          [<ffffffff81109541>] might_fault+0x89/0xac
          [<ffffffff81149cff>] filldir+0x6f/0xc7
          [<ffffffff811586ea>] dcache_readdir+0x67/0x205
          [<ffffffff81149f54>] vfs_readdir+0x7b/0xb4
          [<ffffffff8114a073>] sys_getdents+0x7e/0xd1
          [<ffffffff814e3ec2>] system_call_fastpath+0x16/0x1b

This patch moves the directory vs file lockdep annotation into a helper
function that can be called by in-memory filesystems and has hugetlbfs
call it.
Signed-off-by: NJosh Boyer <jwboyer@redhat.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I ran into a couple of programs which broke with the new Linux 3.0
version.  Some of those were binary only.  I tried to use LD_PRELOAD to
work around it, but it was quite difficult and in one case impossible
because of a mix of 32bit and 64bit executables.

For example, all kind of management software from HP doesnt work, unless
we pretend to run a 2.6 kernel.

  $ uname -a
  Linux svivoipvnx001 3.0.0-08107-g97cd98f #1062 SMP Fri Aug 12 18:11:45 CEST 2011 i686 i686 i386 GNU/Linux

  $ hpacucli ctrl all show

  Error: No controllers detected.

  $ rpm -qf /usr/sbin/hpacucli
  hpacucli-8.75-12.0

Another notable case is that Python now reports "linux3" from
sys.platform(); which in turn can break things that were checking
sys.platform() == "linux2":

  https://bugzilla.mozilla.org/show_bug.cgi?id=664564

It seems pretty clear to me though it's a bug in the apps that are using
'==' instead of .startswith(), but this allows us to unbreak broken
programs.

This patch adds a UNAME26 personality that makes the kernel report a
2.6.40+x version number instead.  The x is the x in 3.x.

I know this is somewhat ugly, but I didn't find a better workaround, and
compatibility to existing programs is important.

Some programs also read /proc/sys/kernel/osrelease.  This can be worked
around in user space with mount --bind (and a mount namespace)

To use:

  wget ftp://ftp.kernel.org/pub/linux/kernel/people/ak/uname26/uname26.c
  gcc -o uname26 uname26.c
  ./uname26 program
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

tty_operations->remove is normally called like:
queue_release_one_tty
 ->tty_shutdown
   ->tty_driver_remove_tty
     ->tty_operations->remove

However tty_shutdown() is called from queue_release_one_tty() only if
tty_operations->shutdown is NULL. But for pty, it is not.
pty_unix98_shutdown() is used there as ->shutdown.

So tty_operations->remove of pty (i.e. pty_unix98_remove()) is never
called. This results in invalid pty_count. I.e. what can be seen in
/proc/sys/kernel/pty/nr.

I see this was already reported at:
  https://lkml.org/lkml/2009/11/5/370
But it was not fixed since then.

This patch is kind of a hackish way. The problem lies in ->install. We
allocate there another tty (so-called tty->link). So ->install is
called once, but ->remove twice, for both tty and tty->link. The fix
here is to count both tty and tty->link and divide the count by 2 for
user.

And to have ->remove called, let's make tty_driver_remove_tty() global
and call that from pty_unix98_shutdown() (tty_operations->shutdown).

While at it, let's document that when ->shutdown is defined,
tty_shutdown() is not called.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Certain platform specific or Host-WiLink Interface specific actions would be
required to be taken when the chip is being enabled and after the chip is
disabled such as configuration of the mux modes for the GPIO of host connected
to the nshutdown of the chip or relinquishing UART after the chip is disabled.

Similar actions can also be taken when the chip is in deep sleep or when the
chip is awake. Performance enhancements such as configuring the host to run
faster when chip is awake and slower when chip is asleep can also be made
here.
Signed-off-by: NPavan Savoy <pavan_savoy@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch changes target_emulate_inquiry_std() to set the 'not connected'
(0x35) bit in standard INQUIRY response data when we are processing a
request to a virtual LUN=0 mapping from struct se_device *g_lun0_dev that
have been setup for us in transport_lookup_cmd_lun().

This addresses an issue where qla2xxx FC clients need to be able
to create demo-mode I_T FC Nexuses by default, but should not be
exposing the default set of TPG LUNs to all FC clients.  This includes
adding an new optional target_core_fabric_ops->tpg_check_demo_mode_login_only()
caller to allow demo_mode nexuses to skip the old default of bulding
a demo-mode MappedLUNs list via core_tpg_add_node_to_devs().

(roland: Add missing tpg_check_demo_mode_login_only check in core_dev_add_lun)
Reported-by: NRoland Dreier <roland@purestorage.com>
Cc: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: NNicholas Bellinger <nab@risingtidesystems.com>

Do not call ->suspend, ->resume methods after we unregister wiphy. Also
delete sta_clanup timer after we finish wiphy unregister to avoid this:

WARNING: at lib/debugobjects.c:262 debug_print_object+0x85/0xa0()
Hardware name: 6369CTO
ODEBUG: free active (active state 0) object type: timer_list hint: sta_info_cleanup+0x0/0x180 [mac80211]
Modules linked in: aes_i586 aes_generic fuse bridge stp llc autofs4 sunrpc cpufreq_ondemand acpi_cpufreq mperf ext2 dm_mod uinput thinkpad_acpi hwmon sg arc4 rt2800usb rt2800lib crc_ccitt rt2x00usb rt2x00lib mac80211 cfg80211 i2c_i801 iTCO_wdt iTCO_vendor_support e1000e ext4 mbcache jbd2 sd_mod crc_t10dif sr_mod cdrom yenta_socket ahci libahci pata_acpi ata_generic ata_piix i915 drm_kms_helper drm i2c_algo_bit video [last unloaded: microcode]
Pid: 5663, comm: pm-hibernate Not tainted 3.1.0-rc1-wl+ #19
Call Trace:
 [<c0454cfd>] warn_slowpath_common+0x6d/0xa0
 [<c05e05e5>] ? debug_print_object+0x85/0xa0
 [<c05e05e5>] ? debug_print_object+0x85/0xa0
 [<c0454dae>] warn_slowpath_fmt+0x2e/0x30
 [<c05e05e5>] debug_print_object+0x85/0xa0
 [<f8a808e0>] ? sta_info_alloc+0x1a0/0x1a0 [mac80211]
 [<c05e0bd2>] debug_check_no_obj_freed+0xe2/0x180
 [<c051175b>] kfree+0x8b/0x150
 [<f8a126ae>] cfg80211_dev_free+0x7e/0x90 [cfg80211]
 [<f8a13afd>] wiphy_dev_release+0xd/0x10 [cfg80211]
 [<c068d959>] device_release+0x19/0x80
 [<c05d06ba>] kobject_release+0x7a/0x1c0
 [<c07646a8>] ? rtnl_unlock+0x8/0x10
 [<f8a13adb>] ? wiphy_resume+0x6b/0x80 [cfg80211]
 [<c05d0640>] ? kobject_del+0x30/0x30
 [<c05d1a6d>] kref_put+0x2d/0x60
 [<c05d056d>] kobject_put+0x1d/0x50
 [<c08015f4>] ? mutex_lock+0x14/0x40
 [<c068d60f>] put_device+0xf/0x20
 [<c069716a>] dpm_resume+0xca/0x160
 [<c04912bd>] hibernation_snapshot+0xcd/0x260
 [<c04903df>] ? freeze_processes+0x3f/0x90
 [<c049151b>] hibernate+0xcb/0x1e0
 [<c048fdc0>] ? pm_async_store+0x40/0x40
 [<c048fe60>] state_store+0xa0/0xb0
 [<c048fdc0>] ? pm_async_store+0x40/0x40
 [<c05d0200>] kobj_attr_store+0x20/0x30
 [<c0575ea4>] sysfs_write_file+0x94/0xf0
 [<c051e26a>] vfs_write+0x9a/0x160
 [<c0575e10>] ? sysfs_open_file+0x200/0x200
 [<c051e3fd>] sys_write+0x3d/0x70
 [<c080959f>] sysenter_do_call+0x12/0x28

Cc: stable@kernel.org
Signed-off-by: NStanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Revert the pass-good area introduced in ffd1f609 ("writeback:
introduce max-pause and pass-good dirty limits") and make the max-pause
area smaller and safe.

This fixes ~30% performance regression in the ext3 data=writeback
fio_mmap_randwrite_64k/fio_mmap_randrw_64k test cases, where there are
12 JBOD disks, on each disk runs 8 concurrent tasks doing reads+writes.

Using deadline scheduler also has a regression, but not that big as CFQ,
so this suggests we have some write starvation.

The test logs show that

- the disks are sometimes under utilized

- global dirty pages sometimes rush high to the pass-good area for
  several hundred seconds, while in the mean time some bdi dirty pages
  drop to very low value (bdi_dirty << bdi_thresh).  Then suddenly the
  global dirty pages dropped under global dirty threshold and bdi_dirty
  rush very high (for example, 2 times higher than bdi_thresh). During
  which time balance_dirty_pages() is not called at all.

So the problems are

1) The random writes progress so slow that they break the assumption of
   the max-pause logic that "8 pages per 200ms is typically more than
   enough to curb heavy dirtiers".

2) The max-pause logic ignored task_bdi_thresh and thus opens the possibility
   for some bdi's to over dirty pages, leading to (bdi_dirty >> bdi_thresh)
   and then (bdi_thresh >> bdi_dirty) for others.

3) The higher max-pause/pass-good thresholds somehow leads to the bad
   swing of dirty pages.

The fix is to allow the task to slightly dirty over task_bdi_thresh, but
no way to exceed bdi_dirty and/or global dirty_thresh.

Tests show that it fixed the JBOD regression completely (both behavior
and performance), while still being able to cut down large pause times
in balance_dirty_pages() for single-disk cases.
Reported-by: NLi Shaohua <shaohua.li@intel.com>
Tested-by: NLi Shaohua <shaohua.li@intel.com>
Acked-by: NJan Kara <jack@suse.cz>
Signed-off-by: NWu Fengguang <fengguang.wu@intel.com>

This allows the cast in lowmem_page_address (introduced as a warning
fixup to 33dd4e0e "mm: make some struct page's const") to be
removed.

Propagate const'ness to page_to_section() as well since it is required
by __page_to_pfn.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Acked-by: NRik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Followup to 33dd4e0e "mm: make some struct page's const" which missed the
HASHED_PAGE_VIRTUAL case.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit ae1b1539, block: reimplement
FLUSH/FUA to support merge, introduced a performance regression when
running any sort of fsyncing workload using dm-multipath and certain
storage (in our case, an HP EVA).  The test I ran was fs_mark, and it
dropped from ~800 files/sec on ext4 to ~100 files/sec.  It turns out
that dm-multipath always advertised flush+fua support, and passed
commands on down the stack, where those flags used to get stripped off.
The above commit changed that behavior:

static inline struct request *__elv_next_request(struct request_queue *q)
{
        struct request *rq;

        while (1) {
-               while (!list_empty(&q->queue_head)) {
+               if (!list_empty(&q->queue_head)) {
                        rq = list_entry_rq(q->queue_head.next);
-                       if (!(rq->cmd_flags & (REQ_FLUSH | REQ_FUA)) ||
-                           (rq->cmd_flags & REQ_FLUSH_SEQ))
-                               return rq;
-                       rq = blk_do_flush(q, rq);
-                       if (rq)
-                               return rq;
+                       return rq;
                }

Note that previously, a command would come in here, have
REQ_FLUSH|REQ_FUA set, and then get handed off to blk_do_flush:

struct request *blk_do_flush(struct request_queue *q, struct request *rq)
{
        unsigned int fflags = q->flush_flags; /* may change, cache it */
        bool has_flush = fflags & REQ_FLUSH, has_fua = fflags & REQ_FUA;
        bool do_preflush = has_flush && (rq->cmd_flags & REQ_FLUSH);
        bool do_postflush = has_flush && !has_fua && (rq->cmd_flags &
        REQ_FUA);
        unsigned skip = 0;
...
        if (blk_rq_sectors(rq) && !do_preflush && !do_postflush) {
                rq->cmd_flags &= ~REQ_FLUSH;
		if (!has_fua)
			rq->cmd_flags &= ~REQ_FUA;
	        return rq;
	}

So, the flush machinery was bypassed in such cases (q->flush_flags == 0
&& rq->cmd_flags & (REQ_FLUSH|REQ_FUA)).

Now, however, we don't get into the flush machinery at all.  Instead,
__elv_next_request just hands a request with flush and fua bits set to
the scsi_request_fn, even if the underlying request_queue does not
support flush or fua.

The agreed upon approach is to fix the flush machinery to allow
stacking.  While this isn't used in practice (since there is only one
request-based dm target, and that target will now reflect the flush
flags of the underlying device), it does future-proof the solution, and
make it function as designed.

In order to make this work, I had to add a field to the struct request,
inside the flush structure (to store the original req->end_io).  Shaohua
had suggested overloading the union with rb_node and completion_data,
but the completion data is used by device mapper and can also be used by
other drivers.  So, I didn't see a way around the additional field.

I tested this patch on an HP EVA with both ext4 and xfs, and it recovers
the lost performance.  Comments and other testers, as always, are
appreciated.

Cheers,
Jeff
Signed-off-by: NJeff Moyer <jmoyer@redhat.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Function genpd_queue_power_off_work() is not defined for
CONFIG_PM_RUNTIME, so pm_genpd_poweroff_unused() causes a build
error to happen in that case.  Fix the problem by making
pm_genpd_poweroff_unused() depend on CONFIG_PM_RUNTIME too.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>