freezer: set PF_SUSPEND_TASK flag on tasks that call freeze_processes

Calling freeze_processes sets a global flag that will cause any
process that calls try_to_freeze to enter the refrigerator.  It
skips sending a signal to the current task, but if the current
task ever hits try_to_freeze, all threads will be frozen and the
system will deadlock.

Set a new flag, PF_SUSPEND_TASK, on the task that calls
freeze_processes.  The flag notifies the freezer that the thread
is involved in suspend and should not be frozen.  Also add a
WARN_ON in thaw_processes if the caller does not have the
PF_SUSPEND_TASK flag set to catch if a different task calls
thaw_processes than the one that called freeze_processes, leaving
a task with PF_SUSPEND_TASK permanently set on it.

Threads that spawn off a task with PF_SUSPEND_TASK set (which
swsusp does) will also have PF_SUSPEND_TASK set, preventing them
from freezing while they are helping with suspend, but they need
to be dead by the time suspend is triggered, otherwise they may
run when userspace is expected to be frozen.  Add a WARN_ON in
thaw_processes if more than one thread has the PF_SUSPEND_TASK
flag set.

Reported-and-tested-by: Michael Leun <lkml20130126@newton.leun.net>
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>
block: cfq: merge tweaked tunables.

Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
Revert "msm: msm_bus: Change MDP port interleaved setting"

This reverts commit 594a06698d3cecdee7f896ce3ec8baadd158311e.
Revert "mako: Add DSI clock control for MDP GDHS power collapse"

This reverts commit 26f0f2f1b5a6841a311442ab70cd3c7cd86e6a06.
Revert "msm: display: Add DSI clock control for MDP GDHS power collapse"

This reverts commit 3c9b29a57f71440f5f182458023f57817182ce8b.
Revert "msm_fb: display: fix iommu page fault when iommu buffer freed"

This reverts commit 5938c62f812d718b992a07d866a705b30d3659a3.