drbd: rcu_read_[un]lock() for all idr accesses that do not sleep

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 563427bfc274..5abbdaf04663 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -453,8 +453,10 @@ void tl_clear(struct drbd_tconn *tconn)
         }
 
         /* ensure bit indicating barrier is required is clear */
+        rcu_read_lock();
         idr_for_each_entry(&tconn->volumes, mdev, vnr)
                 clear_bit(CREATE_BARRIER, &mdev->flags);
+        rcu_read_unlock();
 
         spin_unlock_irq(&tconn->req_lock);
 }
@@ -634,13 +636,15 @@ char *drbd_task_to_thread_name(struct drbd_tconn *tconn, struct task_struct *tas
 
 int conn_lowest_minor(struct drbd_tconn *tconn)
 {
-        int vnr = 0;
         struct drbd_conf *mdev;
+        int vnr = 0, m;
 
+        rcu_read_lock();
         mdev = idr_get_next(&tconn->volumes, &vnr);
-        if (!mdev)
-                return -1;
-        return mdev_to_minor(mdev);
+        m = mdev ? mdev_to_minor(mdev) : -1;
+        rcu_read_unlock();
+
+        return m;
 }
 
 #ifdef CONFIG_SMP