nvme-rdma: Add warning on state change failure at nvme_rdma_setup_ctrl

The transition to LIVE state should not fail in case of a new controller.
Moving to DELETING state before nvme_tcp_create_ctrl() allocates all the
resources may leads to NULL dereference at teardown flow (e.g., IO tagset,
admin_q, connect_q).
Signed-off-by: Israel Rukshin <israelr@mellanox.com>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

drivers/nvme/host/rdma.c

@@ -1022,8 +1022,13 @@ static int nvme_rdma_setup_ctrl(struct nvme_rdma_ctrl *ctrl, bool new)
 
 	changed = nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_LIVE);
 	if (!changed) {
-		/* state change failure is ok if we're in DELETING state */
+		/*
+		 * state change failure is ok if we're in DELETING state,
+		 * unless we're during creation of a new controller to
+		 * avoid races with teardown flow.
+		 */
 		WARN_ON_ONCE(ctrl->ctrl.state != NVME_CTRL_DELETING);
+		WARN_ON_ONCE(new);
 		ret = -EINVAL;
 		goto destroy_io;
 	}