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path: root/drivers/char/tty_port.c
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Diffstat (limited to 'drivers/char/tty_port.c')
-rw-r--r--drivers/char/tty_port.c41
1 files changed, 41 insertions, 0 deletions
diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c
index 6fadb19d630..553b0e9d8d1 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);