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yaml
---
r: 163802
b: refs/heads/master
c: f0de0e8
h: refs/heads/master
v: v3
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Linus Torvalds authored and Live-CD User committed Sep 19, 2009
1 parent 480611b commit 40594e4
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Showing 2 changed files with 40 additions and 27 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 7a4b23104bd2624d16681158a9b338c502c103a0
refs/heads/master: f0de0e8d3565ee7feba6228d99763d4cea2087a6
65 changes: 39 additions & 26 deletions trunk/drivers/char/tty_ldisc.c
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -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;
}

Expand Down Expand Up @@ -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;
}

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