ldsem_down_read_trylock  293 drivers/tty/tty_ldisc.c 	if (ldsem_down_read_trylock(&tty->ldisc_sem)) {
ldsem_down_read_trylock  156 include/linux/tty_ldisc.h extern int ldsem_down_read_trylock(struct ld_semaphore *sem);