rcu: The rcu_needs_cpu() function is not a quiescent state
Paul E. McKenney [Thu, 10 May 2012 22:37:48 +0000 (15:37 -0700)]
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>

kernel/rcutiny_plugin.h

index fc31a2d..849ede5 100644 (file)
@@ -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;
 }