mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-22 12:14:01 +08:00
2febdb632b
Eliminate the requirement of specifying the tty lock nesting at lock time; instead, set the lock subclass for slave ptys at pty install (normal ttys and master ptys use subclass 0). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
67 lines
1.3 KiB
C
67 lines
1.3 KiB
C
#include <linux/tty.h>
|
|
#include <linux/module.h>
|
|
#include <linux/kallsyms.h>
|
|
#include <linux/semaphore.h>
|
|
#include <linux/sched.h>
|
|
|
|
/*
|
|
* Nested tty locks are necessary for releasing pty pairs.
|
|
* The stable lock order is master pty first, then slave pty.
|
|
*/
|
|
|
|
/* Legacy tty mutex glue */
|
|
|
|
enum {
|
|
TTY_MUTEX_NORMAL,
|
|
TTY_MUTEX_SLAVE,
|
|
};
|
|
|
|
/*
|
|
* Getting the big tty mutex.
|
|
*/
|
|
|
|
void __lockfunc tty_lock(struct tty_struct *tty)
|
|
{
|
|
if (tty->magic != TTY_MAGIC) {
|
|
pr_err("L Bad %p\n", tty);
|
|
WARN_ON(1);
|
|
return;
|
|
}
|
|
tty_kref_get(tty);
|
|
mutex_lock(&tty->legacy_mutex);
|
|
}
|
|
EXPORT_SYMBOL(tty_lock);
|
|
|
|
void __lockfunc tty_unlock(struct tty_struct *tty)
|
|
{
|
|
if (tty->magic != TTY_MAGIC) {
|
|
pr_err("U Bad %p\n", tty);
|
|
WARN_ON(1);
|
|
return;
|
|
}
|
|
mutex_unlock(&tty->legacy_mutex);
|
|
tty_kref_put(tty);
|
|
}
|
|
EXPORT_SYMBOL(tty_unlock);
|
|
|
|
void __lockfunc tty_lock_slave(struct tty_struct *tty)
|
|
{
|
|
if (tty && tty != tty->link) {
|
|
WARN_ON(!mutex_is_locked(&tty->link->legacy_mutex) ||
|
|
!tty->driver->type == TTY_DRIVER_TYPE_PTY ||
|
|
!tty->driver->type == PTY_TYPE_SLAVE);
|
|
tty_lock(tty);
|
|
}
|
|
}
|
|
|
|
void __lockfunc tty_unlock_slave(struct tty_struct *tty)
|
|
{
|
|
if (tty && tty != tty->link)
|
|
tty_unlock(tty);
|
|
}
|
|
|
|
void tty_set_lock_subclass(struct tty_struct *tty)
|
|
{
|
|
lockdep_set_subclass(&tty->legacy_mutex, TTY_MUTEX_SLAVE);
|
|
}
|