tty-ldisc: make refcount be atomic_t 'users' count

[safe/jmp/linux-2.6] / drivers / char / tty_ldisc.c

diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c
index acd76b7..fd175e6 100644 (file)
--- a/drivers/char/tty_ldisc.c
+++ b/drivers/char/tty_ldisc.c
@@ -142,7 +142,7 @@ static struct tty_ldisc *tty_ldisc_try_get(int disc)
                        /* lock it */
                        ldops->refcount++;
                        ld->ops = ldops;
-                       ld->refcount = 0;
+                       atomic_set(&ld->users, 0);
                        err = 0;
                }
        }
@@ -206,7 +206,7 @@ static void tty_ldisc_put(struct tty_ldisc *ld)
        ldo->refcount--;
        module_put(ldo->owner);
        spin_unlock_irqrestore(&tty_ldisc_lock, flags);
-       WARN_ON(ld->refcount);
+       WARN_ON(atomic_read(&ld->users));
        kfree(ld);
 }
 
@@ -297,7 +297,7 @@ static int tty_ldisc_try(struct tty_struct *tty)
        spin_lock_irqsave(&tty_ldisc_lock, flags);
        ld = tty->ldisc;
        if (test_bit(TTY_LDISC, &tty->flags)) {
-               ld->refcount++;
+               atomic_inc(&ld->users);
                ret = 1;
        }
        spin_unlock_irqrestore(&tty_ldisc_lock, flags);
@@ -324,7 +324,7 @@ struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty)
 {
        /* wait_event is a macro */
        wait_event(tty_ldisc_wait, tty_ldisc_try(tty));
-       WARN_ON(tty->ldisc->refcount == 0);
+       WARN_ON(atomic_read(&tty->ldisc->users) == 0);
        return tty->ldisc;
 }
 EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait);
@@ -365,11 +365,9 @@ void tty_ldisc_deref(struct tty_ldisc *ld)
        BUG_ON(ld == NULL);
 
        spin_lock_irqsave(&tty_ldisc_lock, flags);
-       if (ld->refcount == 0)
+       if (atomic_read(&ld->users) == 0)
                printk(KERN_ERR "tty_ldisc_deref: no references.\n");
-       else
-               ld->refcount--;
-       if (ld->refcount == 0)
+       else if (atomic_dec_and_test(&ld->users))
                wake_up(&tty_ldisc_wait);
        spin_unlock_irqrestore(&tty_ldisc_lock, flags);
 }
@@ -536,10 +534,10 @@ static int tty_ldisc_wait_idle(struct tty_struct *tty)
 {
        unsigned long flags;
        spin_lock_irqsave(&tty_ldisc_lock, flags);
-       while (tty->ldisc->refcount) {
+       while (atomic_read(&tty->ldisc->users)) {
                spin_unlock_irqrestore(&tty_ldisc_lock, flags);
                if (wait_event_timeout(tty_ldisc_wait,
-                               tty->ldisc->refcount == 0, 5 * HZ) == 0)
+                               atomic_read(&tty->ldisc->users) == 0, 5 * HZ) == 0)
                        return -EBUSY;
                spin_lock_irqsave(&tty_ldisc_lock, flags);
        }