1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/tty.h> 3 #include <linux/module.h> 4 #include <linux/kallsyms.h> 5 #include <linux/semaphore.h> 6 #include <linux/sched.h> 7 #include "tty.h" 8 9 /* Legacy tty mutex glue */ 10 11 /* 12 * Getting the big tty mutex. 13 */ 14 15 void tty_lock(struct tty_struct *tty) 16 { 17 if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty)) 18 return; 19 tty_kref_get(tty); 20 mutex_lock(&tty->legacy_mutex); 21 } 22 EXPORT_SYMBOL(tty_lock); 23 24 int tty_lock_interruptible(struct tty_struct *tty) 25 { 26 int ret; 27 28 if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty)) 29 return -EIO; 30 tty_kref_get(tty); 31 ret = mutex_lock_interruptible(&tty->legacy_mutex); 32 if (ret) 33 tty_kref_put(tty); 34 return ret; 35 } 36 37 void tty_unlock(struct tty_struct *tty) 38 { 39 if (WARN(tty->magic != TTY_MAGIC, "U Bad %p\n", tty)) 40 return; 41 mutex_unlock(&tty->legacy_mutex); 42 tty_kref_put(tty); 43 } 44 EXPORT_SYMBOL(tty_unlock); 45 46 void tty_lock_slave(struct tty_struct *tty) 47 { 48 if (tty && tty != tty->link) 49 tty_lock(tty); 50 } 51 52 void tty_unlock_slave(struct tty_struct *tty) 53 { 54 if (tty && tty != tty->link) 55 tty_unlock(tty); 56 } 57 58 void tty_set_lock_subclass(struct tty_struct *tty) 59 { 60 lockdep_set_subclass(&tty->legacy_mutex, TTY_LOCK_SLAVE); 61 } 62