The refcount is checked only in tty_unregister_ldisc and EBUSY returned
if it is nonzero. But none of the tty_unregister_ldisc callers act
anyhow if this (or any other) error is returned. So remove
tty_ldisc_ops::refcount completely and make tty_unregister_ldisc return
'void' in the next patches. That means we assume tty_unregister_ldisc is
not called while the ldisc might be in use. That relies on
try_module_get in get_ldops and module_put in put_ldops.
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
drivers/tty/n_tty.c | 2 +-
drivers/tty/tty_ldisc.c | 14 +++-----------
include/linux/tty_ldisc.h | 2 --
3 files changed, 4 insertions(+), 14 deletions(-)
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 2fe27905c398..0ec93f1a61f5 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2450,7 +2450,7 @@ void n_tty_inherit_ops(struct tty_ldisc_ops *ops)
{
*ops = n_tty_ops;
ops->owner = NULL;
- ops->refcount = ops->flags = 0;
+ ops->flags = 0;
}
EXPORT_SYMBOL_GPL(n_tty_inherit_ops);
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index d02deeb5e584..98e8316fd28a 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -69,7 +69,6 @@ int tty_register_ldisc(struct tty_ldisc_ops *new_ldisc)
raw_spin_lock_irqsave(&tty_ldiscs_lock, flags);
tty_ldiscs[new_ldisc->num] = new_ldisc;
- new_ldisc->refcount = 0;
raw_spin_unlock_irqrestore(&tty_ldiscs_lock, flags);
return ret;
@@ -90,16 +89,12 @@ EXPORT_SYMBOL(tty_register_ldisc);
int tty_unregister_ldisc(struct tty_ldisc_ops *ldisc)
{
unsigned long flags;
- int ret = 0;
raw_spin_lock_irqsave(&tty_ldiscs_lock, flags);
- if (tty_ldiscs[ldisc->num]->refcount)
- ret = -EBUSY;
- else
- tty_ldiscs[ldisc->num] = NULL;
+ tty_ldiscs[ldisc->num] = NULL;
raw_spin_unlock_irqrestore(&tty_ldiscs_lock, flags);
- return ret;
+ return 0;
}
EXPORT_SYMBOL(tty_unregister_ldisc);
@@ -113,10 +108,8 @@ static struct tty_ldisc_ops *get_ldops(int disc)
ldops = tty_ldiscs[disc];
if (ldops) {
ret = ERR_PTR(-EAGAIN);
- if (try_module_get(ldops->owner)) {
- ldops->refcount++;
+ if (try_module_get(ldops->owner))
ret = ldops;
- }
}
raw_spin_unlock_irqrestore(&tty_ldiscs_lock, flags);
return ret;
@@ -127,7 +120,6 @@ static void put_ldops(struct tty_ldisc_ops *ldops)
unsigned long flags;
raw_spin_lock_irqsave(&tty_ldiscs_lock, flags);
- ldops->refcount--;
module_put(ldops->owner);
raw_spin_unlock_irqrestore(&tty_ldiscs_lock, flags);
}
diff --git a/include/linux/tty_ldisc.h b/include/linux/tty_ldisc.h
index c20ca6a75b4c..fbe9de278629 100644
--- a/include/linux/tty_ldisc.h
+++ b/include/linux/tty_ldisc.h
@@ -208,8 +208,6 @@ struct tty_ldisc_ops {
const char *fp, int count);
struct module *owner;
-
- int refcount;
};
struct tty_ldisc {
--
2.31.1
