From: Paul E. McKenney <paul.mckenney@linaro.org>
Date: Fri, 3 Aug 2012 00:43:50 +0000 (-0700)
Subject: rcu: Remove _rcu_barrier() dependency on __stop_machine()
X-Git-Tag: omap-for-v3.7-rc1/fixes-cpufreq-signed~101^2~1^2~2^4~4
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1331e7a1bbe1;p=pandora-kernel.git

rcu: Remove _rcu_barrier() dependency on __stop_machine()

Currently, _rcu_barrier() relies on preempt_disable() to prevent
any CPU from going offline, which in turn depends on CPU hotplug's
use of __stop_machine().

This patch therefore makes _rcu_barrier() use get_online_cpus() to
block CPU-hotplug operations.  This has the added benefit of removing
the need for _rcu_barrier() to adopt callbacks:  Because CPU-hotplug
operations are excluded, there can be no callbacks to adopt.  This
commit simplifies the code accordingly.

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

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