tree 450c8e5e2d69c6e8b6fd7820d6a7dc112d60325b
parent 3f5d3ea64f1783f0d4ea0d35890ae3297f045a8b
author Paul E. McKenney <paul.mckenney@linaro.org> 1336603482 -0700
committer Paul E. McKenney <paulmck@linux.vnet.ibm.com> 1341257662 -0700

rcu: Add ACCESS_ONCE() to ->qlen accesses

The _rcu_barrier() function accesses other CPUs' rcu_data structure's
->qlen field without benefit of locking.  This commit therefore adds
the required ACCESS_ONCE() wrappers around accesses and updates that
need it.

ACCESS_ONCE() is not needed when a CPU accesses its own ->qlen, or
in code that cannot run while _rcu_barrier() is sampling ->qlen fields.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>