Add Zen I/O scheduler. Similar to SIO, primarily based on no-op and deadline. Intended to be mostly FCFS. Simpler than SIO in many ways, one of them being write requests/read requests have mostly the same priority.

Conflicts:

	block/Kconfig.iosched
	block/Makefile

Signed-off-by: Luis Cruz <ljc2491@gmail.com>
Oops
I/O scheduler adjustments, reduce fifo_batch to 1 on deadline and zen

Conflicts:

	block/sio-iosched.c
	block/vr-iosched.c

Signed-off-by: Luis Cruz <ljc2491@gmail.com>
Some cleanups to zen I/O scheduler
Adjust zen comments
block: zen: fix a bug in add_request, should use rq_is_sync
Increase max readahead
cpufreq: Preserve sysfs files across suspend/resume

The file permissions of cpufreq per-cpu sysfs files are not preserved
across suspend/resume because we internally go through the CPU
Hotplug path which reinitializes the file permissions on CPU online.

But the user is not supposed to know that we are using CPU hotplug
internally within suspend/resume (IOW, the kernel should not silently
wreck the user-set file permissions across a suspend cycle).
Therefore, we need to preserve the file permissions as they are
across suspend/resume.

The simplest way to achieve that is to just not touch the sysfs files
at all - ie., just ignore the CPU hotplug notifications in the
suspend/resume path (_FROZEN) in the cpufreq hotplug callback.

Reported-by: Robert Jarzmik <robert.jarzmik@intel.com>
Reported-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This fixes the problem on d2-aokpx with hot reboots due to Emergency
R/O Remount.
Since we set universal R/W permissions for cpufreq-related sysfs,
on cpu hotplug suspends/resume the permissions were readjusted. Causing
the remount (on ocassion using sysrq to force it, I believe), which
made the device reboot as defined in fs/namespace for remounts.

Conflicts:

	drivers/cpufreq/cpufreq.c

Signed-off-by: Luis Cruz <ljc2491@gmail.com>
Squash reverts of freezable commits
-In preparation of Franco's more complete implementation

Revert "af_unix: use freezable blocking calls in read"

This reverts commit da1d3d64b86b56732556cab48127153d56307cb5.

Revert "sigtimedwait: use freezable blocking call"

This reverts commit 297b6b507d0140910dadf65ddf7d166d9c050bfa.

Revert "nanosleep: use freezable blocking call"

This reverts commit 443afc1832c88702a7c2aac16bb6dbd7278b24cd.

Revert "futex: use freezable blocking call"

This reverts commit 40f55e2d238977b4ab2fa7d09d5aa566f473d4c6.

Revert "select: use freezable blocking call"

This reverts commit 520300c047d7e76493275ff8286e1eb12b1dfdb6.

Revert "epoll: use freezable blocking call"

This reverts commit db5ed7a808ccd0aac6d76781d8e38ba034b1727a.

Revert "binder: use freezable blocking calls"

This reverts commit 960440ed9792a5bbf839ca1f5edf5e57ea365a5b.

Revert "freezer: add new freezable helpers using freezer_do_not_count()"

This reverts commit 28c3b13de3952c6a679e458f03d491d465b77de9.

Revert "freezer: skip waking up tasks with PF_FREEZER_SKIP set"

This reverts commit ebbab55faad011eb19a6c6ca5010ae08bf5dd0f0.

Revert "freezer: shorten freezer sleep time using exponential backoff"

This reverts commit 4086690b3744ca73258c431fc80e01464980aca4.
freezer: shorten freezer sleep time using exponential backoff

Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
freezer: add unsafe versions of freezable helpers for NFS

NFS calls the freezable helpers with locks held, which is unsafe
and will cause lockdep warnings when 6aa9707 "lockdep: check
that no locks held at freeze time" is reapplied (it was reverted
in dbf520a).  NFS shouldn't be doing this, but it has
long-running syscalls that must hold a lock but also shouldn't
block suspend.  Until NFS freeze handling is rewritten to use a
signal to exit out of the critical section, add new *_unsafe
versions of the helpers that will not run the lockdep test when
6aa9707 is reapplied, and call them from NFS.

In practice the likley result of holding the lock while freezing
is that a second task blocked on the lock will never freeze,
aborting suspend, but it is possible to manufacture a case using
the cgroup freezer, the lock, and the suspend freezer to create
a deadlock.  Silencing the lockdep warning here will allow
problems to be found in other drivers that may have a more
serious deadlock risk, and prevent new problems from being added.

Signed-off-by: Colin Cross <ccross@android.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>

Conflicts:

	include/linux/freezer.h

Signed-off-by: Luis Cruz <ljc2491@gmail.com>
freezer: add unsafe versions of freezable helpers for CIFS

CIFS calls wait_event_freezekillable_unsafe with a VFS lock held,
which is unsafe and will cause lockdep warnings when 6aa9707
"lockdep: check that no locks held at freeze time" is reapplied
(it was reverted in dbf520a).  CIFS shouldn't be doing this, but
it has long-running syscalls that must hold a lock but also
shouldn't block suspend.  Until CIFS freeze handling is rewritten
to use a signal to exit out of the critical section, add a new
wait_event_freezekillable_unsafe helper that will not run the
lockdep test when 6aa9707 is reapplied, and call it from CIFS.

In practice the likley result of holding the lock while freezing
is that a second task blocked on the lock will never freeze,
aborting suspend, but it is possible to manufacture a case using
the cgroup freezer, the lock, and the suspend freezer to create
a deadlock.  Silencing the lockdep warning here will allow
problems to be found in other drivers that may have a more
serious deadlock risk, and prevent new problems from being added.

Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
lockdep: remove task argument from debug_check_no_locks_held

The only existing caller to debug_check_no_locks_held calls it
with 'current' as the task, and the freezer needs to call
debug_check_no_locks_held but doesn't already have a current
task pointer, so remove the argument.  It is already assuming
that the current task is relevant by dumping the current stack
trace as part of the warning.

This was originally part of 6aa9707099c (lockdep: check that
no locks held at freeze time) which was reverted in
dbf520a9d7d4.

Original-author: Mandeep Singh Baines <msb@chromium.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
lockdep: check that no locks held at freeze time

We shouldn't try_to_freeze if locks are held.  Holding a lock can cause a
deadlock if the lock is later acquired in the suspend or hibernate path
(e.g.  by dpm).  Holding a lock can also cause a deadlock in the case of
cgroup_freezer if a lock is held inside a frozen cgroup that is later
acquired by a process outside that group.

History:
This patch was originally applied as 6aa9707099c and reverted in
dbf520a9d7d4 because NFS was freezing with locks held.  It was
deemed better to keep the bad freeze point in NFS to allow laptops
to suspend consistently.  The previous patch in this series converts
NFS to call _unsafe versions of the freezable helpers so that
lockdep doesn't complain about them until a more correct fix
can be applied.

[akpm@linux-foundation.org: export debug_check_no_locks_held]
Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
freezer: skip waking up tasks with PF_FREEZER_SKIP set

Android goes through suspend/resume very often (every few seconds when
on a busy wifi network with the screen off), and a significant portion
of the energy used to go in and out of suspend is spent in the
freezer.  If a task has called freezer_do_not_count(), don't bother
waking it up.  If it happens to wake up later it will call
freezer_count() and immediately enter the refrigerator.

Combined with patches to convert freezable helpers to use
freezer_do_not_count() and convert common sites where idle userspace
tasks are blocked to use the freezable helpers, this reduces the
time and energy required to suspend and resume.

Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
freezer: convert freezable helpers to freezer_do_not_count()

Freezing tasks will wake up almost every userspace task from
where it is blocking and force it to run until it hits a
call to try_to_sleep(), generally on the exit path from the syscall
it is blocking in.  On resume each task will run again, usually
restarting the syscall and running until it hits the same
blocking call as it was originally blocked in.

Convert the existing wait_event_freezable* wrappers to use
freezer_do_not_count().  Combined with a previous patch,
these tasks will not run during suspend or resume unless they wake
up for another reason, in which case they will run until they hit
the try_to_freeze() in freezer_count(), and then continue processing
the wakeup after tasks are thawed.

This results in a small change in behavior, previously a race
between freezing and a normal wakeup would be won by the wakeup,
now the task will freeze and then handle the wakeup after thawing.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
freezer: convert freezable helpers to static inline where possible

Some of the freezable helpers have to be macros because their
condition argument needs to get evaluated every time through
the wait loop.  Convert the others to static inline to make
future changes easier.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
freezer: add new freezable helpers using freezer_do_not_count()

Freezing tasks will wake up almost every userspace task from
where it is blocking and force it to run until it hits a
call to try_to_sleep(), generally on the exit path from the syscall
it is blocking in.  On resume each task will run again, usually
restarting the syscall and running until it hits the same
blocking call as it was originally blocked in.

To allow tasks to avoid running on every suspend/resume cycle,
this patch adds additional freezable wrappers around blocking calls
that call freezer_do_not_count().  Combined with the previous patch,
these tasks will not run during suspend or resume unless they wake
up for another reason, in which case they will run until they hit
the try_to_freeze() in freezer_count(), and then continue processing
the wakeup after tasks are thawed.

Additional patches will convert the most common locations that
userspace blocks in to use freezable helpers.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
binder: use freezable blocking calls

Avoid waking up every thread sleeping in a binder call during
suspend and resume by calling a freezable blocking call.  Previous
patches modified the freezer to avoid sending wakeups to threads
that are blocked in freezable blocking calls.

This call was selected to be converted to a freezable call because
it doesn't hold any locks or release any resources when interrupted
that might be needed by another freezing task or a kernel driver
during suspend, and is a common site where idle userspace tasks are
blocked.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
epoll: use freezable blocking call

Avoid waking up every thread sleeping in an epoll_wait call during
suspend and resume by calling a freezable blocking call.  Previous
patches modified the freezer to avoid sending wakeups to threads
that are blocked in freezable blocking calls.

This call was selected to be converted to a freezable call because
it doesn't hold any locks or release any resources when interrupted
that might be needed by another freezing task or a kernel driver
during suspend, and is a common site where idle userspace tasks are
blocked.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>