tty: Fix tty_port kref screwup

[linux-2.6-omap-h63xx.git] / drivers / char / tty_port.c

diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c
index 6fadb19d630b0ab6d749a033fab2e39c26457841..c8f8024cb40e5d6b4fcc6ad1a8f4408104e9f81a 100644 (file)
--- 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_kref_get(tty);
+       spin_unlock_irqrestore(&port->lock, flags);
+}
+EXPORT_SYMBOL(tty_port_tty_set);