42 	n = line->head - line->tail;  in write_room()
97 		line->tail = line->buffer;  in buffer_data()
103 	end = line->buffer + LINE_BUFSIZE - line->tail;  in buffer_data()
106 		memcpy(line->tail, buf, len);  in buffer_data()
107 		line->tail += len;  in buffer_data()
111 		memcpy(line->tail, buf, end);  in buffer_data()
114 		line->tail = line->buffer + len - end;  in buffer_data()
133 	if ((line->buffer == NULL) || (line->head == line->tail))  in flush_buffer()
136 	if (line->tail < line->head) {  in flush_buffer()
156 	count = line->tail - line->head;  in flush_buffer()
164 	return line->head == line->tail;  in flush_buffer()
198 	if (line->head != line->tail)  in line_write()
265 		line->tail = line->buffer;  in line_write_interrupt()