summaryrefslogtreecommitdiffstats
path: root/drivers/char
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/tty_ldisc.c65
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;
}
OpenPOWER on IntegriCloud