The names to the functions that acquire and release a console lock
have changed, but kernel/power/consoleearlysuspend.c still uses the old
names. See http://goo.gl/pxgOK

Change-Id: Ie972e51e1acfcec3a12c8fdc86b9287104346a99
mmc: core: Allow changing bus frequency for SD/eMMC cards in runtime

Currently, bus frequency is set during the card initialization and
never changed until a new card is inserted. In some low power use
cases, scaling the clock frequencies while the card is in transfer
state would allow power savings. This change allows bus frequency
to be changed after the card initialization.

Change-Id: Iac064221199f69d162d91f5311becd735c15700a
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
mmc: block: reduce the block timeout to 30 secs

After completion of block write request, MMC block driver waits for the
card to come out of the programming state. If card doesn't come out of
the programming state in 10 mins, it would be considered as error
condition and card would reinitialized. But this 10 mins is just too huge
and if card is continuously stuck in programming state for 10 mins,
mmcqd thread would take increase the CPU load significantly as we are
continuously polling for the card status (by sending status commands).

This patch reduces this timeout from 10 mins to 30 secs which is quite
reasonable for all well-behaved cards.

Change-Id: I4e8eaf29c836a81419220f312ee867b0dd5cccc7
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
mmc: block: Update error handling if block data is not available

While handling IOCTL command, if the block is not available then in the
bail-out path it is trying to free the block data which will be executed
against NULL pointer.

So, don't attempt to free the block data and only release the IOCTL
data.

CRs-Fixed: 476581
Change-Id: Icba46c861258d2d84b1fae5a2f5fca52ffe54255
Signed-off-by: Pratibhasagar V <pratibha@codeaurora.org>
mmc: core: Add load based clock scaling support

The SD3.0/eMMC4.5/SDIO3.0 cards can support clock rates upto
200MHz (SDR104 or HS200 bus speed modes). For some workloads
like video playback it isn't necessary for these cards to run
at such high speed. Running at lower frequency, say 50MHz, in
such cases can still meet the deadlines for data transfers.
Scaling down the clock frequency dynamically has huge power
savings not only because the bus is running at lower frequency
but also has an advantage of scaling down the system core
voltage, if supported.

Provide an ondemand clock scaling support similar to cpufreq
ondemand governor having two thresholds, up_threshold and
down_threshold to decide whether to increase the frequency or
scale it down respectively. The sampling interval is in the
order of milliseconds and should be chosen by host drivers that
enable MMC_CAP2_CLK_SCALE capability to take advantage of clock
scaling. The sampling interval mainly depends on the the clock
switching delays and hence a host driver decision. If sampling
interval is too low frequent switching of frequencies can lead
to high power consumption and if sampling interval is too high,
the clock scaling logic would take long time to realize that the
underlying hardware (controller and card) is busy and scale up
the clocks.

Change-Id: I22a5054beec41b0b66b3bf030ddfcf284de448b3
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
mmc: core: Add sysfs entries for dynamic control of clock scaling

Add sysfs attributes to allow dynamic control of clock scaling
parameters. These attributes are used to enable/disable clock
scaling at runtime and change the up_threshold, down_threshold,
and polling_interval values. Complete documentation for these
sysfs entries are provided at "Documentation/mmc/mmc-dev-attrs.txt".

Change-Id: I4753c75c3b3eeea91e93bceba7af2535b793612e
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
mmc: core: claim mmc host while enabling clock scaling from userspace

A race condition can occur while enabling clock scaling and removal
of the card. If the card is removed just after the host->card check
is successful then there could be NULL pointer dereference later.
Claim mmc host before card availability check to avoid this race
condition.

Change-Id: I6339cad5857732ec6b66280940cd6b8b7ed30614
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
mmc: core: run clock scaling only in valid card state

Clock scaling requires the tuning and if the tuning command
is sent to the card in invalid state, tuning procedure will
fail.

With urgent request mechanism implemented, there is a chance
that clock scaling invoked when card is not in a proper state
to receive the tuning command.

This change checks the card state (by sending the status command)
before invoking the clock scaling request.

Change-Id: Icb71a8e74a9afdc70380a5901cd3d28931959e9c
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
mmc: core: Log MMC clock frequency transitions

Use kernel's ftrace support to capture MMC clock frequency
transitions which can be useful for debugging issues related
to power consumption.

Usage:
mount -t debugfs none /sys/kernel/debug
echo 1 > /sys/kernel/debug/tracing/events/mmc/mmc_clk/enable
cat /sys/kernel/debug/tracing/trace_pipe

Change-Id: I25c4ee39dcbe30e7665902a9f723a5a421b55ca3
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
mmc: core: Add support for notifying host driver while scaling clocks

Host drivers can participate in clock scaling by registering
->notify_load host operation, which allows host driver to carry out
platform specific operations for further power savings or increasing
throughput based on whether load is LOW or HIGH respectively. This
can be applicable to non-ultra high speed cards as well so remove
the check for ultra high speed cards to initialize clock scaling.

Change-Id: Icaab9520135e384f5470db68b2f25c5cdce5663a
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
mmc: msm_sdcc: Add support for dynamic bus clock vote

SDCC controller on some targets like 8660, 8960, 8064 and their
variants connects with Daytona Fabric (DFAB). To achieve max.
possible performance the DFAB clock is voted to 64MHz at the
cost of some power consumption. Since we now have dynamic clock
scaling for SD/eMMC clock we can also scale the DFAB clock
accordingly without impact on performance but have some power
savings in low throughput cases.

Change-Id: Ic26541d6845b65803aa813d672ccabdfc4658d9c
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
mmc: msm_sdcc: fix a type mismatch in msmsdccc_config_dma()

msmsdcc_prep_xfer() function returns a signed integer value but
caller function msmsdcc_config_dma() is storing this value in an unsigned
integer variable which is obviously not the correct thing to do.

CRs-Fixed: 476578
Change-Id: I39159e2f4f73c7f54de359cbe4faba5e902915ff
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
mmc: msm_sdcc: Enable clock scaling capability

Enable capability, MMC_CAP2_CLK_SCALE to allow mmc core
to scale the clocks at runtime based on load on card.

Clock scaling in MSM platforms also allow voltage scaling between
NOMINAL and SVS levels, thus allowing additional power savings.

Change-Id: Id1995ffea7a6c06a2e8b29b43da70894f35f6c0b
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
Revert "mmc: block: Update error handling if block data is not available"

This reverts commit d14d51efabca5ee83486952e56931586133dfd89.
misc: uidstat: avoid create_stat() race and blockage.

* create_stat() race would lead to:
  [   58.132324] proc_dir_entry 'uid_stat/10061' already registered

* blocking kmalloc reported by sbranden
 tcp_read_sock()
  uid_stat_tcp_rcv()
    create_stat()
      kmalloc(GFP_KERNEL)

Signed-off-by: JP Abgrall <jpa@google.com>
ashmem: avoid deadlock between read and mmap calls

Avoid holding ashmem_mutex across code that can page fault.  Page faults
grab the mmap_sem for the process, which are also held by mmap calls
prior to calling ashmem_mmap, which locks ashmem_mutex.  The reversed
order of locking between the two can deadlock.

The calls that can page fault are read() and the ASHMEM_SET_NAME and
ASHMEM_GET_NAME ioctls.  Move the code that accesses userspace pages
outside the ashmem_mutex.

Bug: 9261835
Change-Id: If1322e981d29c889a56cdc9dfcbc6df2729a45e9
Signed-off-by: Todd Poynor <toddpoynor@google.com>
cpufreq: interactive: Bring in line with Google's 3.4

cpufreq: interactive: take idle notifications only when active

Register an idle notifier only when the governor is active.  Also
short-circuit work of idle end if the governor is not enabled.

Signed-off-by: Sam Leffler <sleffler@chromium.org>
Change-Id: I4cae36dd2e7389540d337d74745ffbaa0131870f

cpufreq: interactive: keep freezer happy when not current governor

Fix a problem where the hung task mechanism was deeming the interactive
clock boost thread as hung.  This was because the thread is created at
module init but never run/woken up until needed.  If the governor is not
being used this can be forever.  To workaround this explicitly wake up
the thread once all the necessary data structures are initialized.  The
latter required some minor code shuffle.

Signed-off-by: Sam Leffler <sleffler@chromium.org>
Change-Id: Ie2c058dd75dcb6460ea10e7ac997e46baf66b1fe

cpufreq: interactive: handle speed up and down in the realtime task

Not useful to have a separate, non-realtime workqueue for speed down
events, avoid priority inversion for speed up events.

Change-Id: Iddcd05545245c847aa1bbe0b8790092914c813d2
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: remove input_boost handling

Now handled in userspace Power HAL instead.

Change-Id: I78a4a2fd471308bfcd785bbefcc65fede27314cf
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: always limit initial speed bump to hispeed

First bump speed up to hispeed_freq whenever the current speed is below
hispeed_freq, instead of only when the current speed is the minimum speed.
The previous code made it too difficult to use hispeed_freq as a common
intermediate speed on systems that frequently run at speeds between
minimum and hispeed_freq.

Change-Id: I04ec30bafabf5741e267ff289209b8c2d846824b
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: run at fraction of hispeed_freq when load is low

When load is below go_hispeed_load, apply the percentage of CPU load to
a max frequency of hispeed_freq instead of the max speed.  This avoids
jumping too quickly to hispeed_freq when it is a relatively low
percentage of max speed.  This also allows go_hispeed_load to be set to
a high percentage relative to hispeed_freq (as a percentage of max speed,
again useful when hispeed_freq is a low fraction of max speed), to cap
larger loads at hispeed_freq.  For example, a load of 60% will typically
move to 60% of hispeed_freq, not 60% of max speed.  This causes the
governor to apply two different speed caps, depending on whether load is
below or above go_hispeed_load.

Also fix the type of hispeed_freq, which was u64, to match other
speed data types (and avoid overhead and allow division).

Change-Id: Ie2d0668be161c074aaad77db2037505431457b3a
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: pin timers to associated CPU

Helps avoid waking up other CPUs to react to activity on the local CPU.

Change-Id: Ife272aaa7916894a437705d44521b1a1693fbe8e
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: use deferrable timer by default

Avoid wakeups only to handle the governor timer when the system is otherwise
idle.

For platforms where the power cost of remaining in idle at higher CPU
speed may outweigh the cost of a governor wakeup from idle to lower the speed,
set parameter cpufreq_interactive.governidle=1.

Change-Id: Id6c43eb35caecf9b0574fcdd5b769711bc7e6de6
Signed-off-by: LianWei WANG <a22439@motorola.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: kick timer on idle exit past expiry

The deferrable timer list isn't checked on all idle exits, such as when
hi-res timers expire or ISRs schedule workers.  If the idle loop is
exited and it's past time to run the governor load polling timer,
run it immediately.  This ensures we handle load spikes caused by actvity
that does not run the normal timer list.

Rename the field that timestamps the "time_in_idle" value to be more
accurate.

Change-Id: Ied590ecbefc83c9a9ec5eb9e31903557f6fa1614
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: trace actual speed in target speed decisions

Tracing adds actual speed since this is expected to be key to the
choice of target speed.

Change-Id: Iec936102d0010c4e9dfa143c38a9fd0d551189c3
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: change speed according to current speed and target load

Add a target_load attribute that specifies how aggressively the governor is
to adjust speed to meet the observed load.  New target speed is calculated
as the current actual speed (may be higher than target speed on SMP) times
the CPU load (as a fraction) divided by target load (fraction).

cpufreq_frequency_table_target() call use CPUFREQ_RELATION_L to set
the next higher speed rather than next lower speed.

Change-Id: If432451da82f5fed12e15c9421d7d27792376150
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: apply above_hispeed_delay to each step above hispeed

Apply above_hispeed_delay whenever increasing speed to a new speed above
hispeed (not just the first step above hispeed).

Change-Id: Ibb7add7db47f2a4306a9458c4e1ebabb60698636
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: allow arbitrary speed / target load mappings

Accept a string of target loads and speeds at which to apply the
target loads, per the documentation update in this patch.  For example,
"85 1000000:90 1700000:99" targets CPU load 85% below speed 1GHz,  90%
at or above 1GHz, until 1.7GHz and above, at which load 99% is targeted.

Attempt to avoid oscillations by evaluating the current speed
weighted by current load against each new choice of speed, choosing a
higher speed if the current load requires a higher speed.

Change-Id: Ie3300206047c84eca5a26b0b63ea512e5207550e
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: remove load since last speed change

The longer-term load since last speed change isn't terribly useful,
may delay recognition of dropping load, and would need forthcoming
changes to adjust load for changing CPU speeds.  Drop it.

Change-Id: Ic3cbb0542cc3484617031787e03ed9bdd632dec1
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: adjust load for changes in speed

Add notifier for speed transitions.  Keep a count of CPU active
microseconds times current frequency, converted to a percentage relative
to the current frequency when load is evaluated.

Change-Id: I5c27adb11081c50490219784ca57cc46e97fc28c
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: specify duration of CPU speed boost pulse

Sysfs attribute boostpulse_duration specifies the duration of boosting CPU
speed in response to bootpulse events.  Duration is specified in usecs,
default 80ms.

Change-Id: Ifd41625574891a44f1787a4e85d1e7b4f2afb52b
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: add timer slack to limit idle at speed > min

Always use deferrable timer for load sampling.

Set a non-deferrable timer to an additional slack time to allow prior to
waking up from idle to drop speed when not at minimum speed.  Slack value
-1 avoids wakeups to drop speed.  Default is 80ms.

Remove the governidle module param and its timer management in idle.  For
platforms on which holding speed above mimum in idle costs power, use the
new timer slack to select how long to wait before waking up to drop speed.

Change-Id: I270b3980667e2c70a68e5bff534124b4411dbad5
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: fix boosting logic

35a84de cpufreq: interactive: apply above_hispeed_delay to each step above hispeed

caused the speed choice logic to osciallate between boosting and not boosting.
Add back code to ensure speed does not drop below boost frequency while
boosting.

Change-Id: Id420068480fcc7f5c4989ff523e2a8d22e2f4db2
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: fix racy timer stopping

When stopping the governor, del_timer_sync() can race against an
invocation of the idle notifier callback, which has the potential
to reactivate the timer.

To fix this issue, a read-write semaphore is used. Multiple readers are
allowed as long as pcpu->governor_enabled is true.  However it can be
moved to false only after taking a write semaphore which would wait for
any on-going asynchronous activities to complete and prevent any more of
those activities to be initiated.

[toddpoynor@google.com: cosmetic and commit text changes]
Change-Id: Ib51165a735d73dcf964a06754c48bdc1913e13d0
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>

cpufreq: interactive: fix race on timer restart on governor start

Starting the governor, or restarting on a hotplugged-in CPU, can race
with the timer start in idle, triggering a BUG on timer already pending.
Start the timer before setting the enable flag, and use enable_sem to
protect the sequence (and ensure correct order of the update to the
enable flag).  Delete any existing timer for safety.

Change-Id: Ife77cf9fe099e8fd8543224cbf148c6722c2ffb0
Reported-by: Francisco Franco <francisco.franco@cloudcar.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: default go_hispeed_load 99%, doc updates

Update default go_hispeed_load from 85% to 99%.  Recent changes to the
governor now use a default target_load of 90%.  go_hispeed_load should
not be lower than the target load for hispeed_freq, which could lead
to oscillating speed decisions.  Other recent changes reduce the need
to dampen speed jumps on load spikes, while input event boosts from
userspace are the preferred method for anticipating load spikes with
UI impacts.

General update to the documentation to reflect recent changes.

Change-Id: I1b92f3091f42c04b10503cd1169a943b5dfd6faf
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: init default values at compile time

Change-Id: Ia4966e949a6c24c34fdbd4a6e522cd7c37e4108e
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: don't handle transition notification if not enabled

If multiple governors are in use then avoid processing frequency transition
notifications for CPUs on which the interactive governor is not enabled.

Change-Id: Ibd75255b921d887501a64774a8c4f62302f2d4e4
Reported-by: Francisco Franco <francisco.franco@cloudcar.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: fix deadlock on spinlock in timer

Need to use irqsave/restore spinlock calls to avoid a deadlock in calls
from the timer.

Change-Id: I15b6b590045ba1447e34ca7b5ff342723e53a605
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: fix race on governor start/stop

There is race condition when both two cpu do CPUFREQ_GOV_STOP and one cpu
do CPUFREQ_GOV_START soon. The sysfs_remove_group is not done yet on one
cpu, but sysfs_create_group is called on another cpu, which cause governor
start failed and then kernel panic in timer callback because the policy and
cpu mask are all kfree in cpufreq driver.

Replace atomic with mutex to lock the whole START/STOP sequence.

Change-Id: I3762b3d44315ae021b8275aca84f5ea9147cc540
Signed-off-by: Lianwei Wang <a22439@motorola.com>

cpufreq: interactive: Enable CPU utilization statistics

 * Notify of CPU utilization on the speedchange task. This is required
   for MPDecision to properly consider hotplug scenarios.

Change-Id: If01a2efb7a7630544b16c782989406ac44865f61

cpufreq: interactive: allow arbitrary speed / delay mappings

Accept a string of delays and speeds at which to apply the delay before
raising each step above hispeed. For example, "80000 1300000:200000
1500000:40000" means that the delay at or above 1GHz, until 1.3GHz is 80 msecs,
the delay until 1.5GHz is 200 msecs and the delay at or above 1.5GHz is 40
msecs when hispeed_freq is 1GHz.

[toddpoynor@google.com: add documentation]
Change-Id: Ifeebede8b1acbdd0a53e5c6916bccbf764dc854f
Signed-off-by: Minsung Kim <ms925.kim@samsung.com>

cpufreq: interactive: add io_is_busy interface

Previously the idle time returned from get_cpu_idle_time_us included the
iowait time. So the iowait time was always calculated as idle time.

But now the idle time returned from get_cpu_idle_time_us does not include
the iowait time anymore because of below commit which cause the iowait time
always calculated as busy time:
    6beea0c nohz: Fix update_ts_time_stat idle accounting

Add the io_is_busy interface, as does the ondemand governor, and let the user
configure the iowait time as busy or idle through the io_is_busy sysfs
interface.

By default, io_is_busy is disabled.

[toddpoynor@google.com: minor updates]
Change-Id: If7d70ff864c43bc9c8d7fd7cfc66f930d339f9b4
Signed-off-by: Lianwei Wang <lian-wei.wang@motorola.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: fix crash on error paths in get_tokenized_data

Use separate variable for error code, free proper pointer.

Change-Id: Ia83cccb195997789ac6afbf5b8761f7b278196d6
Reported-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>

cpufreq: interactive: base above_hispeed_delay on target freq, not current

Time to wait should be based on the intended target speed, not the
actual speed (which may be held high by another CPU).

Change-Id: Ifc5bb55d06adddb9a02af90af05398a78f282272
Reported-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
cpufreq: interactive: Fix uninitialized spinlock

Change-Id: I9959669e0f643ccd2bd1072fae440d8c20f1c9cc
block: Adding ROW scheduling algorithm

This patch adds the implementation of a new scheduling algorithm - ROW.
The policy of this algorithm is to prioritize READ requests over WRITE
as much as possible without starving the WRITE requests.

Change-Id: I4ed52ea21d43b0e7c0769b2599779a3d3869c519
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: ROW: Correct minimum values of ROW tunable parameters

The ROW scheduling algorithm exposes several tunable parameters.
This patch updates the minimum allowed values for those parameters.

Change-Id: I5ec19d54b694e2e83ad5376bd99cc91f084967f5
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: ROW: Fix forced dispatch

This patch fixes forced dispatch in the ROW scheduling algorithm.
When the dispatch function is called with the forced flag on, we
can't delay the dispatch of the requests that are in scheduler queues.
Thus, when dispatch is called with forced turned on, we need to cancel
idling, or not to idle at all.

Change-Id: I3aa0da33ad7b59c0731c696f1392b48525b52ddc
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: Add support for reinsert a dispatched req

Add support for reinserting a dispatched request back to the
scheduler's internal data structures.
This capability is used by the device driver when it chooses to
interrupt the current request transmission and execute another (more
urgent) pending request. For example: interrupting long write in order
to handle pending read. The device driver re-inserts the
remaining write request back to the scheduler, to be rescheduled
for transmission later on.

Add API for verifying whether the current scheduler
supports reinserting requests mechanism. If reinsert mechanism isn't
supported by the scheduler, this code path will never be activated.

Change-Id: I5c982a66b651ebf544aae60063ac8a340d79e67f
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: Add API for urgent request handling

This patch add support in block & elevator layers for handling
urgent requests. The decision if a request is urgent or not is taken
by the scheduler. Urgent request notification is passed to the underlying
block device driver (eMMC for example). Block device driver may decide to
interrupt the currently running low priority request to serve the new
urgent request. By doing so READ latency is greatly reduced in read&write
collision scenarios.

Note that if the current scheduler doesn't implement the urgent request
mechanism, this code path is never activated.

Change-Id: I8aa74b9b45c0d3a2221bd4e82ea76eb4103e7cfa
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

row: Adding support for reinsert already dispatched req

Add support for reinserting already dispatched request back to the
schedulers internal data structures.
The request will be reinserted back to the queue (head) it was
dispatched from as if it was never dispatched.

Change-Id: I70954df300774409c25b5821465fb3aa33d8feb5
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block:row: fix idling mechanism in ROW

This patch addresses the following issues found in the ROW idling
mechanism:
1. Fix the delay passed to queue_delayed_work (pass actual delay
   and not the time when to start the work)
2. Change the idle time and the idling-trigger frequency to be
   HZ dependent (instead of using msec_to_jiffies())
3. Destroy idle_workqueue() in queue_exit

Change-Id: If86513ad6b4be44fb7a860f29bd2127197d8d5bf
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

cfq-iosched: Fix null pointer dereference

NULL pointer dereference can happen in cfq_choose_cfqg()
when there are no cfq groups to select other than the
current serving group. Prevent this by adding a NULL
check before dereferencing.

Unable to handle kernel NULL pointer dereference at virtual address
[<c02502cc>] (cfq_dispatch_requests+0x368/0x8c0) from
[<c0243f30>] (blk_peek_request+0x220/0x25c)
[<c0243f30>] (blk_peek_request+0x220/0x25c) from
[<c0243f74>] (blk_fetch_request+0x8/0x1c)
[<c0243f74>] (blk_fetch_request+0x8/0x1c) from
[<c041cedc>] (mmc_queue_thread+0x58/0x120)
[<c041cedc>] (mmc_queue_thread+0x58/0x120) from
[<c00ad310>] (kthread+0x84/0x90)
[<c00ad310>] (kthread+0x84/0x90) from
[<c000eeac>] (kernel_thread_exit+0x0/0x8)

CRs-Fixed: 416466
Change-Id: I1fab93a4334b53e1d7c5dcc8f93cff174bae0d5e
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>

row: Add support for urgent request handling

This patch adds support for handling urgent requests.
ROW queue can be marked as "urgent" so if it was un-served in last
dispatch cycle and a request was added to it - it will trigger
issuing an urgent-request-notification to the block device driver.
The block device driver may choose at stop the transmission of current
ongoing request to handle the urgent one. Foe example: long WRITE may
be stopped to handle an urgent READ. This decreases READ latency.

Change-Id: I84954c13f5e3b1b5caeadc9fe1f9aa21208cb35e
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: row: Add some debug information on ROW queues

1. Add a counter for number of requests on queue.
2. Add function to print queues status (number requests
   currently on queue and number of already dispatched requests
   in current dispatch cycle).

Change-Id: I1e98b9ca33853e6e6a8ddc53240f6cd6981e6024
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: row: Insert dispatch_quantum into struct row_queue

There is really no point in keeping the dispatch quantum
of a queue outside of it. By inserting it to the row_queue
structure we spare extra level in accessing it.

Change-Id: Ic77571818b643e71f9aafbb2ca93d0a92158b199
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: row: fix sysfs functions - idle_time conversion

idle_time was updated to be stored in msec instead of jiffies.
So there is no need to convert the value when reading from user or
displaying the value to him.

Change-Id: I58e074b204e90a90536d32199ac668112966e9cf
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: row: Aggregate row_queue parameters to one structure

Each ROW queues has several parameters which default values are defined
in separate arrays. This patch aggregates all default values into one
array.
The values in question are:
 - is idling enabled for the queue
 - queue quantum
 - can the queue notify on urgent request

Change-Id: I3821b0a042542295069b340406a16b1000873ec6
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: row: Dispatch requests according to their io-priority

This patch implements "application-hints" which is a way the issuing
application can notify the scheduler on the priority of its request.
This is done by setting the io-priority of the request.
This patch reuses an already existing mechanism of io-priorities developed
for CFQ. Please refer to kernel/Documentation/block/ioprio.txt for
usage example and explanations.

Change-Id: I228ec8e52161b424242bb7bb133418dc8b73925a
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: row: Idling mechanism re-factoring

At the moment idling in ROW is implemented by delayed work that uses
jiffies granularity which is not very accurate. This patch replaces
current idling mechanism implementation with hrtime API, which gives
nanosecond resolution (instead of jiffies).

Change-Id: I86c7b1776d035e1d81571894b300228c8b8f2d92
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: row: Don't notify URGENT if there are un-completed urgent req

When ROW scheduler reports to the block layer that there is an urgent
request pending, the device driver may decide to stop the transmission
of the current request in order to handle the urgent one. If the current
transmitted request is an urgent request - we don't want it to be
stopped.
Due to the above ROW scheduler won't notify of an urgent request if
there are urgent requests in flight.

Change-Id: I2fa186d911b908ec7611682b378b9cdc48637ac7
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: row: Update initial values of ROW data structures

This patch sets the initial values of internal ROW
parameters.

Change-Id: I38132062a7fcbe2e58b9cc757e55caac64d013dc
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>
[smuckle@codeaurora.org: ported from msm-3.7]
Signed-off-by: Steve Muckle <smuckle@codeaurora.org>

block: add REQ_URGENT to request flags

This patch adds a new flag to be used in cmd_flags field of struct request
for marking request as urgent.
Urgent request is the one that should be given priority currently handled
(regular) request by the device driver. The decision of a request urgency
is taken by the scheduler.

Change-Id: Ic20470987ef23410f1d0324f96f00578f7df8717
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: row: Re-design urgent request notification mechanism

When ROW scheduler reports to the block layer that there is an urgent
request pending, the device driver may decide to stop the transmission
of the current request in order to handle the urgent one. This is done
in order to reduce the latency of an urgent request. For example:
long WRITE may be stopped to handle an urgent READ.

This patch updates the ROW URGENT notification policy to apply with the
below:

- Don't notify URGENT if there is an un-completed URGENT request in driver
- After notifying that URGENT request is present, the next request
  dispatched is the URGENT one.
- At every given moment only 1 request can be marked as URGENT.
  Independent of it's location (driver or scheduler)

Other changes to URGENT policy:
- Only READ queues are allowed to notify of an URGENT request pending.

CR fix:
If a pending urgent request (A) gets merged with another request (B)
A is removed from scheduler queue but is not removed from
rd->pending_urgent_rq.

CRs-Fixed: 453712
Change-Id: I321e8cf58e12a05b82edd2a03f52fcce7bc9a900
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: urgent request: remove unnecessary urgent marking

An urgent request is marked by the scheduler in rq->cmd_flags with the
REQ_URGENT flag. There is no need to add an additional marking by
the block layer.

Change-Id: I05d5e9539d2f6c1bfa80240b0671db197a5d3b3f
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: row: Prevent starvation of regular priority by high priority

At the moment all REGULAR and LOW priority requests are starved as long as
there are HIGH priority requests to dispatch.
This patch prevents the above starvation by setting a starvation limit the
REGULAR\LOW priority requests can tolerate.

Change-Id: Ibe24207982c2c55d75c0b0230f67e013d1106017
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: row: Update sysfs functions

All ROW (time related) configurable parameters are stored in ms so there
is no need to convert from/to ms when reading/updating them via sysfs.

Change-Id: Ib6a1de54140b5d25696743da944c076dd6fc02ae
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: urgent request: Update dispatch_urgent in case of requeue/reinsert

The block layer implements a mechanism for verifying that the device
driver won't be notified of an URGENT request if there is already an
URGENT request in flight. This is due to the fact that interrupting an
URGENT request isn't efficient.
This patch fixes the above described mechanism in case the URGENT request
was returned back to the block layer from some reason: by requeue or
reinsert.

CRs-fixed: 473376, 473036, 471736
Change-Id: Ie8b8208230a302d4526068531616984825f1050d
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

block: row: Fix starvation tolerance values

The current starvation tolerance values increase the boot time
since high priority SW requests are delayed by regular priority requests.
In order to overcome this, increase the starvation tolerance values.

Change-Id: I9947fca9927cbd39a1d41d4bd87069df679d3103
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>
Signed-off-by: Maya Erez <merez@codeaurora.org>
Add Exfat Kernel support v1.2.7