RDMA/nes: Fix crash when listener destroyed during loopback setup

When a listener is destroyed and there is an MPA response pending for
loopback connection, the active side cm_node gets destroyed twice:
once in cm_event_connect_error() and again in nes_accept()/nes_reject().

Increment the cm_node's refcount so it's not destroyed by
cm_event_connect_error().
Signed-off-by: Faisal Latif <faisal.latif@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/nes/nes_cm.c

@@ -1011,9 +1011,10 @@ static int mini_cm_dec_refcnt_listen(struct nes_cm_core *cm_core,
 					event.cm_info.loc_port =
 							 loopback->loc_port;
 					event.cm_info.cm_id = loopback->cm_id;
+					add_ref_cm_node(loopback);
+					loopback->state = NES_CM_STATE_CLOSED;
 					cm_event_connect_error(&event);
 					cm_node->state = NES_CM_STATE_LISTENER_DESTROYED;
-					loopback->state = NES_CM_STATE_CLOSED;
 
 					rem_ref_cm_node(cm_node->cm_core,
 							 cm_node);