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