From: Paul E. McKenney <paul.mckenney@linaro.org>
Date: Thu, 10 May 2012 22:37:48 +0000 (-0700)
Subject: rcu: The rcu_needs_cpu() function is not a quiescent state
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=28f8555364ef5b54b21251c5c8022109a70626e9;p=linux-beck.git

rcu: The rcu_needs_cpu() function is not a quiescent state

The TINY_PREEMPT_RCU() function rcu_preempt_needs_cpu(), which is called
from rcu_needs_cpu(), assumes that it is in a quiescent state with respect
to the CPU.  This is no longer the case.  This commit therefore updates
rcu_preempt_needs_cpu() to make it aware that it is not running in a
quiescent state.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Pascal Chapperon <pascal.chapperon@wanadoo.fr>
---

diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h
index fc31a2d65100..849ede51c12d 100644
--- a/kernel/rcutiny_plugin.h
+++ b/kernel/rcutiny_plugin.h
@@ -846,8 +846,6 @@ EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);
  */
 int rcu_preempt_needs_cpu(void)
 {
-	if (!rcu_preempt_running_reader())
-		rcu_preempt_cpu_qs();
 	return rcu_preempt_ctrlblk.rcb.rcucblist != NULL;
 }