RDMA/cma: Simplify DEVICE_REMOVAL for internal_id

cma_process_remove() triggers an unconditional rdma_destroy_id() for
internal_id's and skips the event deliver and transition through
RDMA_CM_DEVICE_REMOVAL.

This is confusing and unnecessary. internal_id always has
cma_listen_handler() as the handler, have it catch the
RDMA_CM_DEVICE_REMOVAL event and directly consume it and signal removal.

This way the FSM sequence never skips the DEVICE_REMOVAL case and the
logic in this hard to test area is simplified.

Link: https://lore.kernel.org/r/20200723070707.1771101-2-leon@kernel.orgSigned-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/core/cma.c

@@ -2478,6 +2478,10 @@ static int cma_listen_handler(struct rdma_cm_id *id,
 {
 	struct rdma_id_private *id_priv = id->context;
 
+	/* Listening IDs are always destroyed on removal */
+	if (event->event == RDMA_CM_EVENT_DEVICE_REMOVAL)
+		return -1;
+
 	id->context = id_priv->id.context;
 	id->event_handler = id_priv->id.event_handler;
 	trace_cm_event_handler(id_priv, event);
@@ -4811,7 +4815,7 @@ static void cma_process_remove(struct cma_device *cma_dev)
 		cma_id_get(id_priv);
 		mutex_unlock(&lock);
 
-		ret = id_priv->internal_id ? 1 : cma_remove_id_dev(id_priv);
+		ret = cma_remove_id_dev(id_priv);
 		cma_id_put(id_priv);
 		if (ret)
 			rdma_destroy_id(&id_priv->id);