sched: Fix select_fallback_rq() vs cpu_active/cpu_online

sched: Fix select_fallback_rq() vs cpu_active/cpu_online

Commit 5fbd036b55 ("sched: Cleanup cpu_active madness"), which was
supposed to finally sort the cpu_active mess, instead uncovered more.

Since CPU_STARTING is ran before setting the cpu online, there's a
(small) window where the cpu has active,!online.

If during this time there's a wakeup of a task that used to reside on
that cpu select_task_rq() will use select_fallback_rq() to compute an
alternative cpu to run on since we find !online.

select_fallback_rq() however will compute the new cpu against
cpu_active, this means that it can return the same cpu it started out
with, the !online one, since that cpu is in fact marked active.

This results in us trying to scheduling a task on an offline cpu and
triggering a WARN in the IPI code.

The solution proposed by Chuansheng Liu of setting cpu_active in
set_cpu_online() is buggy, firstly not all archs actually use
set_cpu_online(), secondly, not all archs call set_cpu_online() with
IRQs disabled, this means we would introduce either the same race or
the race from fd8a7de17 ("x86: cpu-hotplug: Prevent softirq wakeup on
wrong CPU") -- albeit much narrower.

[ By setting online first and active later we have a window of
  online,!active, fresh and bound kthreads have task_cpu() of 0 and
  since cpu0 isn't in tsk_cpus_allowed() we end up in
  select_fallback_rq() which excludes !active, resulting in a reset
  of ->cpus_allowed and the thread running all over the place. ]

The solution is to re-work select_fallback_rq() to require active
_and_ online. This makes the active,!online case work as expected,
OTOH archs running CPU_STARTING after setting online are now
vulnerable to the issue from fd8a7de17 -- these are alpha and
blackfin.

Change-Id: I34bedb461f77bfe4af78ef5ddd3fb3a230ca3551
Reported-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: linux-alpha@vger.kernel.org
Link: http://lkml.kernel.org/n/tip-hubqk1i10o4dpvlm06gq7v6j@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Taras Kondratiuk <taras@ti.com>
slub: use __SetPageSlab function to set PG_slab flag

To set page-flag, using SetPageXXXX() and __SetPageXXXX() is more
understandable and maintainable. So change it.
Signed-off-by: Joonsoo Kim <js1304@gmail.com>
OMAPDSS: CEC: Physical address discovery form edid

HDMI sink device will set the physical address for
CEC devices

Change-Id: I6419834816978dfc8bcb8ef9a7b6c36276e5792c
Signed-off-by: Muralidhar Dixit <murali.dixit@ti.com>
modified for TUNA kernel from omapzoom by faux123
OMAPDSS: CEC: Add callback to CEC driver on HDMI HPD

Adding support for call back from HDMI to CEC driver
on HPD and HDMI enable.

Change-Id: I9fff9d41d598e5ef375bc03faafb9a559ce7435a
Signed-off-by: Muralidhar Dixit <murali.dixit@ti.com>
modified for TUNA kernel from omapzoom by faux123