1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0 2*4882a593Smuzhiyun #include <linux/tty.h> 3*4882a593Smuzhiyun #include <linux/module.h> 4*4882a593Smuzhiyun #include <linux/kallsyms.h> 5*4882a593Smuzhiyun #include <linux/semaphore.h> 6*4882a593Smuzhiyun #include <linux/sched.h> 7*4882a593Smuzhiyun 8*4882a593Smuzhiyun /* Legacy tty mutex glue */ 9*4882a593Smuzhiyun 10*4882a593Smuzhiyun /* 11*4882a593Smuzhiyun * Getting the big tty mutex. 12*4882a593Smuzhiyun */ 13*4882a593Smuzhiyun tty_lock(struct tty_struct * tty)14*4882a593Smuzhiyunvoid tty_lock(struct tty_struct *tty) 15*4882a593Smuzhiyun { 16*4882a593Smuzhiyun if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty)) 17*4882a593Smuzhiyun return; 18*4882a593Smuzhiyun tty_kref_get(tty); 19*4882a593Smuzhiyun mutex_lock(&tty->legacy_mutex); 20*4882a593Smuzhiyun } 21*4882a593Smuzhiyun EXPORT_SYMBOL(tty_lock); 22*4882a593Smuzhiyun tty_lock_interruptible(struct tty_struct * tty)23*4882a593Smuzhiyunint tty_lock_interruptible(struct tty_struct *tty) 24*4882a593Smuzhiyun { 25*4882a593Smuzhiyun int ret; 26*4882a593Smuzhiyun 27*4882a593Smuzhiyun if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty)) 28*4882a593Smuzhiyun return -EIO; 29*4882a593Smuzhiyun tty_kref_get(tty); 30*4882a593Smuzhiyun ret = mutex_lock_interruptible(&tty->legacy_mutex); 31*4882a593Smuzhiyun if (ret) 32*4882a593Smuzhiyun tty_kref_put(tty); 33*4882a593Smuzhiyun return ret; 34*4882a593Smuzhiyun } 35*4882a593Smuzhiyun tty_unlock(struct tty_struct * tty)36*4882a593Smuzhiyunvoid tty_unlock(struct tty_struct *tty) 37*4882a593Smuzhiyun { 38*4882a593Smuzhiyun if (WARN(tty->magic != TTY_MAGIC, "U Bad %p\n", tty)) 39*4882a593Smuzhiyun return; 40*4882a593Smuzhiyun mutex_unlock(&tty->legacy_mutex); 41*4882a593Smuzhiyun tty_kref_put(tty); 42*4882a593Smuzhiyun } 43*4882a593Smuzhiyun EXPORT_SYMBOL(tty_unlock); 44*4882a593Smuzhiyun tty_lock_slave(struct tty_struct * tty)45*4882a593Smuzhiyunvoid tty_lock_slave(struct tty_struct *tty) 46*4882a593Smuzhiyun { 47*4882a593Smuzhiyun if (tty && tty != tty->link) 48*4882a593Smuzhiyun tty_lock(tty); 49*4882a593Smuzhiyun } 50*4882a593Smuzhiyun tty_unlock_slave(struct tty_struct * tty)51*4882a593Smuzhiyunvoid tty_unlock_slave(struct tty_struct *tty) 52*4882a593Smuzhiyun { 53*4882a593Smuzhiyun if (tty && tty != tty->link) 54*4882a593Smuzhiyun tty_unlock(tty); 55*4882a593Smuzhiyun } 56*4882a593Smuzhiyun tty_set_lock_subclass(struct tty_struct * tty)57*4882a593Smuzhiyunvoid tty_set_lock_subclass(struct tty_struct *tty) 58*4882a593Smuzhiyun { 59*4882a593Smuzhiyun lockdep_set_subclass(&tty->legacy_mutex, TTY_LOCK_SLAVE); 60*4882a593Smuzhiyun } 61