CIRC_CNT           20 include/linux/circ_buf.h #define CIRC_SPACE(head,tail,size) CIRC_CNT((tail),((head)+1),(size))
CIRC_CNT          355 include/linux/serial_core.h 	(CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))