tag	line	file	source code
LDISC_FLAG_DEFINED	85	kernel/chr_drv/tty_io.c	ldiscs[disc].flags |= LDISC_FLAG_DEFINED;
LDISC_FLAG_DEFINED	275	kernel/chr_drv/tty_ioctl.c	!(ldiscs[ldisc].flags & LDISC_FLAG_DEFINED))