Merge branches 'urgent.2012.10.27a', 'doc.2012.11.16a', 'fixes.2012.11.13a', 'srcu...

urgent.2012.10.27a: Fix for RCU user-mode transition (already in -tip).

doc.2012.11.08a: Documentation updates, most notably codifying the
	memory-barrier guarantees inherent to grace periods.

fixes.2012.11.13a: Miscellaneous fixes.

srcu.2012.10.27a: Allow statically allocated and initialized srcu_struct
	structures (courtesy of Lai Jiangshan).

stall.2012.11.13a: Add more diagnostic information to RCU CPU stall
	warnings, also decrease from 60 seconds to 21 seconds.

hotplug.2012.11.08a: Minor updates to CPU hotplug handling.

tracing.2012.11.08a: Improved debugfs tracing, courtesy of Michael Wang.

idle.2012.10.24a: Updates to RCU idle/adaptive-idle handling, including
	a boot parameter that maps normal grace periods to expedited.

Resolved conflict in kernel/rcutree.c due to side-by-side change.

diff --cc Documentation/RCU/whatisRCU.txt
Simple merge

diff --cc include/linux/rcupdate.h
Simple merge

diff --cc include/linux/sched.h
Simple merge

diff --cc kernel/rcutorture.c
Simple merge

diff --cc kernel/rcutree.c
index 74df86bd9204aef5ec9d14ca8b4b0094777bef87,74df86bd9204aef5ec9d14ca8b4b0094777bef87,15a2beec320fe1f959f773a88a65acebb411b716,74df86bd9204aef5ec9d14ca8b4b0094777bef87,24b21cba2cc80f1a137404846b2cc73df1e76727,8ed9c481db035b4d59f486b6711d12e963b7faaf,effd47a54b361fe8839933b4b4586ef7f7a68455..5ffadcc3bb26e6030580e6a9df23124af638e851
--- 1/kernel/rcutree.c
--- 2/kernel/rcutree.c
--- 3/kernel/rcutree.c
--- 4/kernel/rcutree.c
--- 5/kernel/rcutree.c
--- 6/kernel/rcutree.c
--- 7/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@@@@@@@ -2308,10 -2308,10 -2352,10 -2308,10 -2340,10 -2305,32 -2314,10 +2387,32 @@@@@@@@ static int synchronize_sched_expedited_
        */
       void synchronize_sched_expedited(void)
       {
----- - int firstsnap, s, snap, trycount = 0;
+++++ + long firstsnap, s, snap;
+++++ + int trycount = 0;
+++++ + struct rcu_state *rsp = &rcu_sched_state;
++++   
    - - /* Note that atomic_inc_return() implies full memory barrier. */
    - - firstsnap = snap = atomic_inc_return(&sync_sched_expedited_started);
+++++ + /*
+++++ +  * If we are in danger of counter wrap, just do synchronize_sched().
+++++ +  * By allowing sync_sched_expedited_started to advance no more than
+++++ +  * ULONG_MAX/8 ahead of sync_sched_expedited_done, we are ensuring
+++++ +  * that more than 3.5 billion CPUs would be required to force a
+++++ +  * counter wrap on a 32-bit system.  Quite a few more CPUs would of
+++++ +  * course be required on a 64-bit system.
+++++ +  */
+++++ + if (ULONG_CMP_GE((ulong)atomic_long_read(&rsp->expedited_start),
+++++ +                  (ulong)atomic_long_read(&rsp->expedited_done) +
+++++ +                  ULONG_MAX / 8)) {
+++++ +         synchronize_sched();
+++++ +         atomic_long_inc(&rsp->expedited_wrap);
+++++ +         return;
+++++ + }
    + +
----    /* Note that atomic_inc_return() implies full memory barrier. */
----    firstsnap = snap = atomic_inc_return(&sync_sched_expedited_started);
+++++ + /*
+++++ +  * Take a ticket.  Note that atomic_inc_return() implies a
+++++ +  * full memory barrier.
+++++ +  */
+++++ + snap = atomic_long_inc_return(&rsp->expedited_start);
+++++ + firstsnap = snap;
        get_online_cpus();
        WARN_ON_ONCE(cpu_is_offline(raw_smp_processor_id()));
       
@@@@@@@@ -2328,7 -2328,7 -2372,7 -2328,7 -2360,7 -2357,8 -2334,7 +2439,8 @@@@@@@@
                if (trycount++ < 10) {
                        udelay(trycount * num_online_cpus());
                } else {
------                  synchronize_sched();
++++++                  wait_rcu_gp(call_rcu_sched);
+++++ +                 atomic_long_inc(&rsp->expedited_normal);
                        return;
                }
       

diff --cc kernel/rcutree_plugin.h
Simple merge

diff --cc kernel/sched/core.c
Simple merge

diff --cc kernel/srcu.c
Simple merge