Input: use full RCU API

RT guys alerted me to the fact that in their tree spinlocks
are preemptible and it is better to use full RCU API
(rcu_read_lock()/rcu_read_unlock()) to be safe.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 4 insertions, 7 deletions

diff --git a/drivers/input/joydev.c b/drivers/input/joydev.c
index f306c97f556d..2b201f9aa024 100644
--- a/drivers/input/joydev.c
+++ b/drivers/input/joydev.c
@@ -149,8 +149,10 @@ static void joydev_event(struct input_handle *handle,
 
         event.time = jiffies_to_msecs(jiffies);
 
+        rcu_read_lock();
         list_for_each_entry_rcu(client, &joydev->client_list, node)
                 joydev_pass_event(client, &event);
+        rcu_read_unlock();
 
         wake_up_interruptible(&joydev->wait);
 }
@@ -178,12 +180,7 @@ static void joydev_attach_client(struct joydev *joydev,
         spin_lock(&joydev->client_lock);
         list_add_tail_rcu(&client->node, &joydev->client_list);
         spin_unlock(&joydev->client_lock);
-        /*
-         * We don't use synchronize_rcu() here because read-side
-         * critical section is protected by a spinlock (dev->event_lock)
-         * instead of rcu_read_lock().
-         */
-        synchronize_sched();
+        synchronize_rcu();
 }
 
 static void joydev_detach_client(struct joydev *joydev,
@@ -192,7 +189,7 @@ static void joydev_detach_client(struct joydev *joydev,
         spin_lock(&joydev->client_lock);
         list_del_rcu(&client->node);
         spin_unlock(&joydev->client_lock);
-        synchronize_sched();
+        synchronize_rcu();
 }
 
 static int joydev_open_device(struct joydev *joydev)