43 	n = line->head - line->tail;  in write_room()
97 		line->head = line->buffer;  in buffer_data()
134 	if ((line->buffer == NULL) || (line->head == line->tail))  in flush_buffer()
137 	if (line->tail < line->head) {  in flush_buffer()
139 		count = line->buffer + LINE_BUFSIZE - line->head;  in flush_buffer()
141 		n = write_chan(line->chan_out, line->head, count,  in flush_buffer()
150 			line->head = line->buffer;  in flush_buffer()
152 			line->head += n;  in flush_buffer()
157 	count = line->tail - line->head;  in flush_buffer()
158 	n = write_chan(line->chan_out, line->head, count,  in flush_buffer()
164 	line->head += n;  in flush_buffer()
165 	return line->head == line->tail;  in flush_buffer()
194 	if (line->head != line->tail)  in line_write()
247 		line->head = line->buffer;  in line_write_interrupt()