From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Date: Thu, 19 Aug 2010 23:57:45 +0000 (-0700)
Subject: rcu: apply TINY_PREEMPT_RCU read-side speedup to TREE_PREEMPT_RCU
X-Git-Tag: v2.6.37-rc1~215^2~14^2~2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=80dcf60e6b97c7363971e7a0a788d8484d35f8a6;p=pandora-kernel.git

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>
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