diff options
Diffstat (limited to 'drivers/tty/tty_ldisc.c')
| -rw-r--r-- | drivers/tty/tty_ldisc.c | 61 |
1 files changed, 34 insertions, 27 deletions
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c index 0f2a2c5e704..d794087c327 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -26,7 +26,7 @@ * callers who will do ldisc lookups and cannot sleep. */ -static DEFINE_SPINLOCK(tty_ldisc_lock); +static DEFINE_RAW_SPINLOCK(tty_ldisc_lock); static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait); /* Line disc dispatch table */ static struct tty_ldisc_ops *tty_ldiscs[NR_LDISCS]; @@ -49,22 +49,24 @@ static void put_ldisc(struct tty_ldisc *ld) * If this is the last user, free the ldisc, and * release the ldisc ops. * - * We really want an "atomic_dec_and_lock_irqsave()", + * We really want an "atomic_dec_and_raw_lock_irqsave()", * but we don't have it, so this does it by hand. */ - local_irq_save(flags); - if (atomic_dec_and_lock(&ld->users, &tty_ldisc_lock)) { + raw_spin_lock_irqsave(&tty_ldisc_lock, flags); + if (atomic_dec_and_test(&ld->users)) { struct tty_ldisc_ops *ldo = ld->ops; ldo->refcount--; module_put(ldo->owner); - spin_unlock_irqrestore(&tty_ldisc_lock, flags); + raw_spin_unlock_irqrestore(&tty_ldisc_lock, flags); kfree(ld); return; } - local_irq_restore(flags); - wake_up(&ld->wq_idle); + raw_spin_unlock_irqrestore(&tty_ldisc_lock, flags); + + if (waitqueue_active(&ld->wq_idle)) + wake_up(&ld->wq_idle); } /** @@ -88,11 +90,11 @@ int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc) if (disc < N_TTY || disc >= NR_LDISCS) return -EINVAL; - spin_lock_irqsave(&tty_ldisc_lock, flags); + raw_spin_lock_irqsave(&tty_ldisc_lock, flags); tty_ldiscs[disc] = new_ldisc; new_ldisc->num = disc; new_ldisc->refcount = 0; - spin_unlock_irqrestore(&tty_ldisc_lock, flags); + raw_spin_unlock_irqrestore(&tty_ldisc_lock, flags); return ret; } @@ -118,12 +120,12 @@ int tty_unregister_ldisc(int disc) if (disc < N_TTY || disc >= NR_LDISCS) return -EINVAL; - spin_lock_irqsave(&tty_ldisc_lock, flags); + raw_spin_lock_irqsave(&tty_ldisc_lock, flags); if (tty_ldiscs[disc]->refcount) ret = -EBUSY; else tty_ldiscs[disc] = NULL; - spin_unlock_irqrestore(&tty_ldisc_lock, flags); + raw_spin_unlock_irqrestore(&tty_ldisc_lock, flags); return ret; } @@ -134,7 +136,7 @@ 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); + raw_spin_lock_irqsave(&tty_ldisc_lock, flags); ret = ERR_PTR(-EINVAL); ldops = tty_ldiscs[disc]; if (ldops) { @@ -144,7 +146,7 @@ static struct tty_ldisc_ops *get_ldops(int disc) ret = ldops; } } - spin_unlock_irqrestore(&tty_ldisc_lock, flags); + raw_spin_unlock_irqrestore(&tty_ldisc_lock, flags); return ret; } @@ -152,10 +154,10 @@ static void put_ldops(struct tty_ldisc_ops *ldops) { unsigned long flags; - spin_lock_irqsave(&tty_ldisc_lock, flags); + raw_spin_lock_irqsave(&tty_ldisc_lock, flags); ldops->refcount--; module_put(ldops->owner); - spin_unlock_irqrestore(&tty_ldisc_lock, flags); + raw_spin_unlock_irqrestore(&tty_ldisc_lock, flags); } /** @@ -287,11 +289,11 @@ static struct tty_ldisc *tty_ldisc_try(struct tty_struct *tty) unsigned long flags; struct tty_ldisc *ld; - spin_lock_irqsave(&tty_ldisc_lock, flags); + raw_spin_lock_irqsave(&tty_ldisc_lock, flags); ld = NULL; if (test_bit(TTY_LDISC, &tty->flags)) ld = get_ldisc(tty->ldisc); - spin_unlock_irqrestore(&tty_ldisc_lock, flags); + raw_spin_unlock_irqrestore(&tty_ldisc_lock, flags); return ld; } @@ -512,7 +514,7 @@ static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old) static int tty_ldisc_halt(struct tty_struct *tty) { clear_bit(TTY_LDISC, &tty->flags); - return cancel_work_sync(&tty->buf.work); + return cancel_work_sync(&tty->port->buf.work); } /** @@ -525,7 +527,7 @@ static void tty_ldisc_flush_works(struct tty_struct *tty) { flush_work(&tty->hangup_work); flush_work(&tty->SAK_work); - flush_work(&tty->buf.work); + flush_work(&tty->port->buf.work); } /** @@ -704,9 +706,9 @@ enable: /* Restart the work queue in case no characters kick it off. Safe if already running */ if (work) - schedule_work(&tty->buf.work); + schedule_work(&tty->port->buf.work); if (o_work) - schedule_work(&o_tty->buf.work); + schedule_work(&o_tty->port->buf.work); mutex_unlock(&tty->ldisc_mutex); tty_unlock(tty); return retval; @@ -817,7 +819,7 @@ void tty_ldisc_hangup(struct tty_struct *tty) */ clear_bit(TTY_LDISC, &tty->flags); tty_unlock(tty); - cancel_work_sync(&tty->buf.work); + cancel_work_sync(&tty->port->buf.work); mutex_unlock(&tty->ldisc_mutex); retry: tty_lock(tty); @@ -897,6 +899,11 @@ int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty) static void tty_ldisc_kill(struct tty_struct *tty) { + /* There cannot be users from userspace now. But there still might be + * drivers holding a reference via tty_ldisc_ref. Do not steal them the + * ldisc until they are done. */ + tty_ldisc_wait_idle(tty, MAX_SCHEDULE_TIMEOUT); + mutex_lock(&tty->ldisc_mutex); /* * Now kill off the ldisc @@ -929,17 +936,17 @@ void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty) * race with the set_ldisc code path. */ - tty_lock_pair(tty, o_tty); tty_ldisc_halt(tty); - tty_ldisc_flush_works(tty); - if (o_tty) { + if (o_tty) tty_ldisc_halt(o_tty); + + tty_ldisc_flush_works(tty); + if (o_tty) tty_ldisc_flush_works(o_tty); - } + tty_lock_pair(tty, o_tty); /* This will need doing differently if we need to lock */ tty_ldisc_kill(tty); - if (o_tty) tty_ldisc_kill(o_tty); |