From e4375729ff79417ccf151d161028a02348281e45 Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Mon, 30 Nov 2009 13:17:14 +0000
Subject: [PATCH] --- yaml --- r: 175348 b: refs/heads/master c:
 568aafc627e2978509e8a80c640ba534d1e843cc h: refs/heads/master v: v3

---
 [refs]                        |  2 +-
 trunk/drivers/char/tty_port.c | 18 ++++++++++++++++++
 trunk/include/linux/tty.h     | 12 ++++++++++++
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index bfd424bdcf62..c3168eee00fa 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 338818fd802a6baacb7e5b6910d52c8996ca6d28
+refs/heads/master: 568aafc627e2978509e8a80c640ba534d1e843cc
diff --git a/trunk/drivers/char/tty_port.c b/trunk/drivers/char/tty_port.c
index 84006de2900f..be492dd66437 100644
--- a/trunk/drivers/char/tty_port.c
+++ b/trunk/drivers/char/tty_port.c
@@ -29,6 +29,7 @@ void tty_port_init(struct tty_port *port)
 	spin_lock_init(&port->lock);
 	port->close_delay = (50 * HZ) / 100;
 	port->closing_wait = (3000 * HZ) / 100;
+	kref_init(&port->kref);
 }
 EXPORT_SYMBOL(tty_port_init);
 
@@ -56,6 +57,23 @@ void tty_port_free_xmit_buf(struct tty_port *port)
 }
 EXPORT_SYMBOL(tty_port_free_xmit_buf);
 
+static void tty_port_destructor(struct kref *kref)
+{
+	struct tty_port *port = container_of(kref, struct tty_port, kref);
+	if (port->xmit_buf)
+		free_page((unsigned long)port->xmit_buf);
+	if (port->ops->destruct)
+		port->ops->destruct(port);
+	else
+		kfree(port);
+}
+
+void tty_port_put(struct tty_port *port)
+{
+	if (port)
+		kref_put(&port->kref, tty_port_destructor);
+}
+EXPORT_SYMBOL(tty_port_put);
 
 /**
  *	tty_port_tty_get	-	get a tty reference
diff --git a/trunk/include/linux/tty.h b/trunk/include/linux/tty.h
index e9269ca1542a..e6da667ba34d 100644
--- a/trunk/include/linux/tty.h
+++ b/trunk/include/linux/tty.h
@@ -199,6 +199,8 @@ struct tty_port_operations {
         /* FIXME: long term getting the tty argument *out* of this would be
            good for consoles */
 	int (*activate)(struct tty_port *port, struct tty_struct *tty);
+	/* Called on the final put of a port */
+	void (*destruct)(struct tty_port *port);
 };
 	
 struct tty_port {
@@ -219,6 +221,7 @@ struct tty_port {
 	int			drain_delay;	/* Set to zero if no pure time
 						   based drain is needed else
 						   set to size of fifo */
+	struct kref		kref;		/* Ref counter */
 };
 
 /*
@@ -461,6 +464,15 @@ extern int tty_write_lock(struct tty_struct *tty, int ndelay);
 extern void tty_port_init(struct tty_port *port);
 extern int tty_port_alloc_xmit_buf(struct tty_port *port);
 extern void tty_port_free_xmit_buf(struct tty_port *port);
+extern void tty_port_put(struct tty_port *port);
+
+extern inline struct tty_port *tty_port_get(struct tty_port *port)
+{
+	if (port)
+		kref_get(&port->kref);
+	return port;
+}
+
 extern struct tty_struct *tty_port_tty_get(struct tty_port *port);
 extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
 extern int tty_port_carrier_raised(struct tty_port *port);