On 5/31/22 05:35, Jason Gunthorpe wrote:
On Sat, May 28, 2022 at 09:00:16PM +0200, Bart Van Assche wrote:
On 5/27/22 14:52, Jason Gunthorpe wrote:
That only works if you can detect actual different lock classes during
lock creation. It doesn't seem applicable in this case.
Why doesn't it seem applicable in this case? The default behavior of
mutex_init() and related initialization functions is to create one lock
class per synchronization object initialization caller.
lockdep_register_key() can be used to create one lock class per
synchronization object instance. I introduced lockdep_register_key() myself
a few years ago.
I don't think this should be used to create one key per instance of
the object which would be required here. The overhead would be very
high.
Are we perhaps referring to different code changes? I'm referring to the
code change below. The runtime and memory overhead of the patch below
should be minimal.
Thanks,
Bart.
diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index fabca5e51e3d..d476c64cd84a 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -860,6 +860,8 @@ __rdma_create_id(struct net *net, rdma_cm_event_handler event_handler,
init_completion(&id_priv->comp);
refcount_set(&id_priv->refcount, 1);
mutex_init(&id_priv->handler_mutex);
+ lockdep_register_key(&id_priv->handler_key);
+ lockdep_set_class(&id_priv->handler_mutex, &id_priv->handler_key);
INIT_LIST_HEAD(&id_priv->device_item);
INIT_LIST_HEAD(&id_priv->listen_list);
INIT_LIST_HEAD(&id_priv->mc_list);
@@ -1899,12 +1901,16 @@ static void _destroy_id(struct rdma_id_private *id_priv,
cma_id_put(id_priv);
wait_for_completion(&id_priv->comp);
+ mutex_destroy(&id_priv->handler_mutex);
+ lockdep_unregister_key(&id_priv->handler_key);
+
if (id_priv->internal_id)
cma_id_put(id_priv->id.context);
kfree(id_priv->id.route.path_rec);
put_net(id_priv->id.route.addr.dev_addr.net);
+
kfree(id_priv);
}
diff --git a/drivers/infiniband/core/cma_priv.h b/drivers/infiniband/core/cma_priv.h
index 757a0ef79872..4affecd044eb 100644
--- a/drivers/infiniband/core/cma_priv.h
+++ b/drivers/infiniband/core/cma_priv.h
@@ -75,6 +75,7 @@ struct rdma_id_private {
struct completion comp;
refcount_t refcount;
struct mutex handler_mutex;
+ struct lock_class_key handler_key;
int backlog;
int timeout_ms;
