RDMA/rtrs-srv: Release lock before call into close_sess

In this error case, we don't need hold mutex to call close_sess.

Fixes: 9cb8374804 ("RDMA/rtrs: server: main functionality")
Link: https://lore.kernel.org/r/20201217141915.56989-4-jinpu.wang@cloud.ionos.com
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Tested-by: Lutz Pogrell <lutz.pogrell@cloud.ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/ulp/rtrs/rtrs-srv.c

@@ -1863,8 +1863,8 @@ reject_w_econnreset:
 	return rtrs_rdma_do_reject(cm_id, -ECONNRESET);
 
 close_and_return_err:
-	close_sess(sess);
 	mutex_unlock(&srv->paths_mutex);
+	close_sess(sess);
 
 	return err;
 }