drbd: allow parallel promote/demote actions
We plan to use genl_family->parallel_ops = true in the future,
but need to review all possible interactions first.
For now, only selectively drop genl_lock() in drbd_set_role(),
instead serializing on our own internal resource->conf_update mutex.
We now can be promoted/demoted on many resources in parallel,
which may significantly improve cluster failover times
when fencing is required.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 865fdb3..05db597 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2570,6 +2570,7 @@
INIT_LIST_HEAD(&resource->connections);
list_add_tail_rcu(&resource->resources, &drbd_resources);
mutex_init(&resource->conf_update);
+ mutex_init(&resource->adm_mutex);
spin_lock_init(&resource->req_lock);
return resource;