rcu: rcu_sched_grace_period(): kill the bogus flush_signals()

As a kernel thread, rcu_sched_grace_period() runs with all signals ignored.
It can never receive a signal even if it sleeps in TASK_INTERRUPTIBLE, it
needs the explicit allow_signal() to be visible for signals.

[ Impact: reduce kernel size, remove dead code ]

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <20090503211118.GA22973@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/rcupreempt.c b/kernel/rcupreempt.c
index ce97a4df64d3539edc785ff9db119c3ba3edbe07..beb0e659adcc60be60bcc1efd2c6e9ca45367afe 100644 (file)
--- a/kernel/rcupreempt.c
+++ b/kernel/rcupreempt.c
@@ -1356,17 +1356,11 @@ static int rcu_sched_grace_period(void *arg)
 
                rcu_ctrlblk.sched_sleep = rcu_sched_sleeping;
                spin_unlock_irqrestore(&rcu_ctrlblk.schedlock, flags);
-               ret = 0;
+               ret = 0; /* unused */
                __wait_event_interruptible(rcu_ctrlblk.sched_wq,
                        rcu_ctrlblk.sched_sleep != rcu_sched_sleeping,
                        ret);
 
-               /*
-                * Signals would prevent us from sleeping, and we cannot
-                * do much with them in any case.  So flush them.
-                */
-               if (ret)
-                       flush_signals(current);
                couldsleepnext = 0;
 
        } while (!kthread_should_stop());