[GIT PULL rcu/urgent] Fix two more 4.3 regressions

[Paul E. McKenney]

Hello, Ingo,

This series contains two small fixes for regressions introduced during
the past merge window:

1.	Recent versions of gcc are fatally confused by use of a const
	int variable for array bounds in inline functions, one of which
	was introduced by 114b7fd4b (rcu: Create rcu_sync infrastructure).
	For more information on the gcc bug, see:

		https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67055#c13

	This workaround for that gcc bug, courtesy of Oleg Nesterov,
	simply substitutes the constant expression for the two uses of
	the const int variable.

2.	Commit 2cd6ffafec06 (rcu: Extend expedited funnel locking
	to rcu_data structure) extended contention-reducing
	funnel locking from the rcu_node structures to the rcu_data
	structures, but failed to create a separate lock class for the
	rcu_sched_data structures, which is needed due to the fact that
	synchronize_rcu_expedited() invokes synchronize_sched_expedited().
	In the absence of this separate lock class, lockdep can give
	false-positive splats.	This commit therefore creates the
	required lock class so that lockdep can see that there is in
	fact no deadlock.

Both fixes have been exposed to -next and 0day Test Robot testing.

These changes are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git for-mingo

for you to fetch changes up to 19a5ecde086a6a5287978b12ae948fa691b197b7:

  rcu: Suppress lockdep false positive for rcp->exp_funnel_mutex (2015-09-20 21:01:22 -0700)

----------------------------------------------------------------
Oleg Nesterov (1):
      rcu: Change _wait_rcu_gp() to work around GCC bug 67055

Paul E. McKenney (1):
      rcu: Suppress lockdep false positive for rcp->exp_funnel_mutex

 include/linux/rcupdate.h | 11 +++++------
 kernel/rcu/tree.c        |  5 +++++
 2 files changed, 10 insertions(+), 6 deletions(-)

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