Commit fde86d31 authored by Eric Dumazet's avatar Eric Dumazet Committed by Linus Torvalds

tty: add lockdep annotations

tty_lock_pair() do the right thing to avoid deadlocks, but should
instruct LOCKDEP of this to avoid a splat.
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1d59d61f
......@@ -6,11 +6,17 @@
/* Legacy tty mutex glue */
enum {
TTY_MUTEX_NORMAL,
TTY_MUTEX_NESTED,
};
/*
* Getting the big tty mutex.
*/
void __lockfunc tty_lock(struct tty_struct *tty)
static void __lockfunc tty_lock_nested(struct tty_struct *tty,
unsigned int subclass)
{
if (tty->magic != TTY_MAGIC) {
printk(KERN_ERR "L Bad %p\n", tty);
......@@ -18,7 +24,12 @@ void __lockfunc tty_lock(struct tty_struct *tty)
return;
}
tty_kref_get(tty);
mutex_lock(&tty->legacy_mutex);
mutex_lock_nested(&tty->legacy_mutex, subclass);
}
void __lockfunc tty_lock(struct tty_struct *tty)
{
return tty_lock_nested(tty, TTY_MUTEX_NORMAL);
}
EXPORT_SYMBOL(tty_lock);
......@@ -43,11 +54,11 @@ void __lockfunc tty_lock_pair(struct tty_struct *tty,
{
if (tty < tty2) {
tty_lock(tty);
tty_lock(tty2);
tty_lock_nested(tty2, TTY_MUTEX_NESTED);
} else {
if (tty2 && tty2 != tty)
tty_lock(tty2);
tty_lock(tty);
tty_lock_nested(tty, TTY_MUTEX_NESTED);
}
}
EXPORT_SYMBOL(tty_lock_pair);
......
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