rcu: Remove old memory barriers from rcu_process_callbacks()

 */

static void rcu_process_callbacks(void)

{

	/*

	 * Memory references from any prior RCU read-side critical sections

	 * executed by the interrupted code must be seen before any RCU

	 * grace-period manipulations below.

	 */

	smp_mb(); /* See above block comment. */

	__rcu_process_callbacks(&rcu_sched_state,

				&__get_cpu_var(rcu_sched_data));

	__rcu_process_callbacks(&rcu_bh_state, &__get_cpu_var(rcu_bh_data));

	rcu_preempt_process_callbacks();

	/*

	 * Memory references from any later RCU read-side critical sections

	 * executed by the interrupted code must be seen after any RCU

	 * grace-period manipulations above.

	 */

	smp_mb(); /* See above block comment. */

	/* If we are last CPU on way to dyntick-idle mode, accelerate it. */

	rcu_needs_cpu_flush();

}