diff options
Diffstat (limited to 'drivers/char/tty_port.c')
| -rw-r--r-- | drivers/char/tty_port.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c index 6fadb19d630b..553b0e9d8d17 100644 --- a/drivers/char/tty_port.c +++ b/drivers/char/tty_port.c @@ -23,6 +23,7 @@ void tty_port_init(struct tty_port *port) init_waitqueue_head(&port->open_wait); init_waitqueue_head(&port->close_wait); mutex_init(&port->mutex); + spin_lock_init(&port->lock); port->close_delay = (50 * HZ) / 100; port->closing_wait = (3000 * HZ) / 100; } @@ -53,3 +54,43 @@ void tty_port_free_xmit_buf(struct tty_port *port) EXPORT_SYMBOL(tty_port_free_xmit_buf); +/** + * tty_port_tty_get - get a tty reference + * @port: tty port + * + * Return a refcount protected tty instance or NULL if the port is not + * associated with a tty (eg due to close or hangup) + */ + +struct tty_struct *tty_port_tty_get(struct tty_port *port) +{ + unsigned long flags; + struct tty_struct *tty; + + spin_lock_irqsave(&port->lock, flags); + tty = tty_kref_get(port->tty); + spin_unlock_irqrestore(&port->lock, flags); + return tty; +} +EXPORT_SYMBOL(tty_port_tty_get); + +/** + * tty_port_tty_set - set the tty of a port + * @port: tty port + * @tty: the tty + * + * Associate the port and tty pair. Manages any internal refcounts. + * Pass NULL to deassociate a port + */ + +void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty) +{ + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + if (port->tty) + tty_kref_put(port->tty); + port->tty = tty; + spin_unlock_irqrestore(&port->lock, flags); +} +EXPORT_SYMBOL(tty_port_tty_set); |