#include <linux/tty.h>#include <linux/module.h>#include <linux/kallsyms.h>#include <linux/semaphore.h>#include <linux/sched.h> /* * The 'big tty mutex' * * This mutex is taken and released by tty_lock() and tty_unlock(), * replacing the older big kernel lock. * It can no longer be taken recursively, and does not get * released implicitly while sleeping. * * Don't use in new code. */static DEFINE_MUTEX(big_tty_mutex); /* * Getting the big tty mutex. */void __lockfunc tty_lock(void){	mutex_lock(&big_tty_mutex);}EXPORT_SYMBOL(tty_lock); void __lockfunc tty_unlock(void){	mutex_unlock(&big_tty_mutex);}EXPORT_SYMBOL(tty_unlock);