drbd: drbd_adm_get_status needs to show some more detail

We want to see existing connection objects, even if they do not
currently have volumes attached.

Change the .dumpit variant of drbd_adm_get_status to iterate not over
minor devices, but over connections + volumes.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index ea638ce..5fa7ba0 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -171,6 +171,7 @@
 extern struct ratelimit_state drbd_ratelimit_state;
 extern struct idr minors;
 extern struct list_head drbd_tconns;
+extern struct mutex drbd_cfg_mutex;
 
 /* on the wire */
 enum drbd_packet {
@@ -918,7 +919,7 @@
 
 struct drbd_tconn {			/* is a resource from the config file */
 	char *name;			/* Resource name */
-	struct list_head all_tconn;	/* List of all drbd_tconn, prot by global_state_lock */
+	struct list_head all_tconn;	/* linked on global drbd_tconns */
 	struct idr volumes;		/* <tconn, vnr> to mdev mapping */
 	enum drbd_conns cstate;		/* Only C_STANDALONE to C_WF_REPORT_PARAMS */
 	struct mutex cstate_mutex;	/* Protects graceful disconnects */