commit 80dcf60e6b97c7363971e7a0a788d8484d35f8a6
author Paul E. McKenney <paulmck@linux.vnet.ibm.com> Thu Aug 19 16:57:45 2010 -0700
committer Paul E. McKenney <paulmck@linux.vnet.ibm.com> Fri Aug 20 09:00:17 2010 -0700
tree 2f493fdf6a7a52675733ac74daa9e1cd9342a030
parent 7b0b759b65247cbc66384a912be9acf8d4800636

rcu: apply TINY_PREEMPT_RCU read-side speedup to TREE_PREEMPT_RCU

Replace one of the ACCESS_ONCE() calls in each of __rcu_read_lock()
and __rcu_read_unlock() with barrier() as suggested by Steve Rostedt in
order to avoid the potential compiler-optimization-induced bug noted by
Mathieu Desnoyers.

Located-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>