diff --git a/src/lib-http/http-client-request.c b/src/lib-http/http-client-request.c
index dda7ea4630..e18ba10cb8 100644
--- a/src/lib-http/http-client-request.c
+++ b/src/lib-http/http-client-request.c
@@ -856,7 +856,7 @@ int http_client_request_send_more(struct http_client_request *req,
 			/* finished sending payload */
 			http_client_request_finish_payload_out(req);
 		}
-	} else if (i_stream_get_data_size(req->payload_input) > 0) {
+	} else if (i_stream_have_bytes_left(req->payload_input)) {
 		/* output is blocking (server needs to act; enable timeout) */
 		conn->output_locked = TRUE;
 		if (!pipelined)
diff --git a/src/lib-http/http-server-response.c b/src/lib-http/http-server-response.c
index 56920ed1ce..d9ffe98e53 100644
--- a/src/lib-http/http-server-response.c
+++ b/src/lib-http/http-server-response.c
@@ -526,7 +526,7 @@ int http_server_response_send_more(struct http_server_response *resp,
 		}
 		/* finished sending payload */
 		http_server_response_finish_payload_out(resp);
-	} else if (i_stream_get_data_size(resp->payload_input) > 0) {
+	} else if (i_stream_have_bytes_left(resp->payload_input)) {
 		/* output is blocking */
 		conn->output_locked = TRUE;
 		o_stream_set_flush_pending(output, TRUE);