Fraga: Preemptible RCU that disables preemption
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index e0d31a345..767f352 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -71,7 +71,11 @@
*/
void __rcu_read_lock(void)
{
- current->rcu_read_lock_nesting++;
+ struct task_struct *t = current;
+
+ if (!t->rcu_read_lock_nesting)
+ preempt_disable();
+ t->rcu_read_lock_nesting++;
barrier(); /* critical section after entry code. */
}
EXPORT_SYMBOL_GPL(__rcu_read_lock);
@@ -92,6 +96,7 @@
} else {
barrier(); /* critical section before exit code. */
t->rcu_read_lock_nesting = INT_MIN;
+ preempt_disable();
barrier(); /* assign before ->rcu_read_unlock_special load */
if (unlikely(ACCESS_ONCE(t->rcu_read_unlock_special.s)))
rcu_read_unlock_special(t);
