73 lines
1.4 KiB
C
73 lines
1.4 KiB
C
#include <linux/tty.h>
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#include <linux/module.h>
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#include <linux/kallsyms.h>
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#include <linux/semaphore.h>
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#include <linux/sched.h>
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/* Legacy tty mutex glue */
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enum {
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TTY_MUTEX_NORMAL,
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TTY_MUTEX_NESTED,
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};
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/*
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* Getting the big tty mutex.
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*/
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static void __lockfunc tty_lock_nested(struct tty_struct *tty,
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unsigned int subclass)
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{
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if (tty->magic != TTY_MAGIC) {
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pr_err("L Bad %p\n", tty);
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WARN_ON(1);
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return;
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}
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tty_kref_get(tty);
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mutex_lock_nested(&tty->legacy_mutex, subclass);
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}
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void __lockfunc tty_lock(struct tty_struct *tty)
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{
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return tty_lock_nested(tty, TTY_MUTEX_NORMAL);
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}
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EXPORT_SYMBOL(tty_lock);
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void __lockfunc tty_unlock(struct tty_struct *tty)
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{
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if (tty->magic != TTY_MAGIC) {
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pr_err("U Bad %p\n", tty);
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WARN_ON(1);
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return;
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}
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mutex_unlock(&tty->legacy_mutex);
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tty_kref_put(tty);
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}
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EXPORT_SYMBOL(tty_unlock);
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/*
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* Getting the big tty mutex for a pair of ttys with lock ordering
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* On a non pty/tty pair tty2 can be NULL which is just fine.
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*/
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void __lockfunc tty_lock_pair(struct tty_struct *tty,
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struct tty_struct *tty2)
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{
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if (tty < tty2) {
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tty_lock(tty);
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tty_lock_nested(tty2, TTY_MUTEX_NESTED);
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} else {
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if (tty2 && tty2 != tty)
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tty_lock(tty2);
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tty_lock_nested(tty, TTY_MUTEX_NESTED);
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}
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}
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EXPORT_SYMBOL(tty_lock_pair);
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void __lockfunc tty_unlock_pair(struct tty_struct *tty,
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struct tty_struct *tty2)
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{
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tty_unlock(tty);
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if (tty2 && tty2 != tty)
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tty_unlock(tty2);
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}
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EXPORT_SYMBOL(tty_unlock_pair);
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