| rjw | 1f88458 | 2022-01-06 17:20:42 +0800 | [diff] [blame^] | 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 | } |