drbd: Turn connection->volumes into connection->peer_devices

Let connection->peer_devices point to peer devices; connection->volumes was
pointing to devices.

Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 378e48c..7aa1056 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1890,7 +1890,7 @@
 {
 	struct drbd_connection *connection = thi->connection;
 	struct drbd_work *w = NULL;
-	struct drbd_device *device;
+	struct drbd_peer_device *peer_device;
 	LIST_HEAD(work_list);
 	int vnr;
 
@@ -1934,7 +1934,8 @@
 	} while (!list_empty(&work_list));
 
 	rcu_read_lock();
-	idr_for_each_entry(&connection->volumes, device, vnr) {
+	idr_for_each_entry(&connection->peer_devices, peer_device, vnr) {
+		struct drbd_device *device = peer_device->device;
 		D_ASSERT(device->state.disk == D_DISKLESS && device->state.conn == C_STANDALONE);
 		kref_get(&device->kref);
 		rcu_read_unlock();