diff options
| -rw-r--r-- | drivers/char/tty_ldisc.c | 65 |
1 files changed, 39 insertions, 26 deletions
diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c index e48af9f79219..cbfacc0bbea5 100644 --- a/drivers/char/tty_ldisc.c +++ b/drivers/char/tty_ldisc.c @@ -145,6 +145,34 @@ int tty_unregister_ldisc(int disc) } EXPORT_SYMBOL(tty_unregister_ldisc); +static struct tty_ldisc_ops *get_ldops(int disc) +{ + unsigned long flags; + struct tty_ldisc_ops *ldops, *ret; + + spin_lock_irqsave(&tty_ldisc_lock, flags); + ret = ERR_PTR(-EINVAL); + ldops = tty_ldiscs[disc]; + if (ldops) { + ret = ERR_PTR(-EAGAIN); + if (try_module_get(ldops->owner)) { + ldops->refcount++; + ret = ldops; + } + } + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + return ret; +} + +static void put_ldops(struct tty_ldisc_ops *ldops) +{ + unsigned long flags; + + spin_lock_irqsave(&tty_ldisc_lock, flags); + ldops->refcount--; + module_put(ldops->owner); + spin_unlock_irqrestore(&tty_ldisc_lock, flags); +} /** * tty_ldisc_try_get - try and reference an ldisc @@ -156,36 +184,21 @@ EXPORT_SYMBOL(tty_unregister_ldisc); static struct tty_ldisc *tty_ldisc_try_get(int disc) { - unsigned long flags; struct tty_ldisc *ld; struct tty_ldisc_ops *ldops; - int err = -EINVAL; ld = kmalloc(sizeof(struct tty_ldisc), GFP_KERNEL); if (ld == NULL) return ERR_PTR(-ENOMEM); - spin_lock_irqsave(&tty_ldisc_lock, flags); - ld->ops = NULL; - ldops = tty_ldiscs[disc]; - /* Check the entry is defined */ - if (ldops) { - /* If the module is being unloaded we can't use it */ - if (!try_module_get(ldops->owner)) - err = -EAGAIN; - else { - /* lock it */ - ldops->refcount++; - ld->ops = ldops; - atomic_set(&ld->users, 1); - err = 0; - } - } - spin_unlock_irqrestore(&tty_ldisc_lock, flags); - if (err) { + ldops = get_ldops(disc); + if (IS_ERR(ldops)) { kfree(ld); - return ERR_PTR(err); + return ERR_CAST(ldops); } + + ld->ops = ldops; + atomic_set(&ld->users, 1); return ld; } @@ -234,13 +247,13 @@ static void tty_ldiscs_seq_stop(struct seq_file *m, void *v) static int tty_ldiscs_seq_show(struct seq_file *m, void *v) { int i = *(loff_t *)v; - struct tty_ldisc *ld; + struct tty_ldisc_ops *ldops; - ld = tty_ldisc_try_get(i); - if (IS_ERR(ld)) + ldops = get_ldops(i); + if (IS_ERR(ldops)) return 0; - seq_printf(m, "%-10s %2d\n", ld->ops->name ? ld->ops->name : "???", i); - put_ldisc(ld); + seq_printf(m, "%-10s %2d\n", ldops->name ? ldops->name : "???", i); + put_ldops(ldops); return 0; } |