From 86f1d0a3db4ca6e55eab79e698ad6f97a80acf5c Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Mon, 8 Feb 2010 10:07:04 +0000
Subject: [PATCH] --- yaml --- r: 185201 b: refs/heads/master c:
 e8c65d143a9903cb553c0d80c819428c5b839a02 h: refs/heads/master i:   185199:
 84b4c9ea135fd03cc4318f93c5ab0825f96e39e1 v: v3

---
 [refs]                      |  2 +-
 trunk/drivers/char/nozomi.c | 34 ++++++++++++----------------------
 2 files changed, 13 insertions(+), 23 deletions(-)

diff --git a/[refs] b/[refs]
index 39d3fb84efd7..5cf6ec320c40 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 266794eb71cfee65b38371954b9db2f6dbda207c
+refs/heads/master: e8c65d143a9903cb553c0d80c819428c5b839a02
diff --git a/trunk/drivers/char/nozomi.c b/trunk/drivers/char/nozomi.c
index cd405bcf53a6..fac9157a0ec0 100644
--- a/trunk/drivers/char/nozomi.c
+++ b/trunk/drivers/char/nozomi.c
@@ -1693,15 +1693,7 @@ static int ntty_write(struct tty_struct *tty, const unsigned char *buffer,
 	if (!dc || !port)
 		return -ENODEV;
 
-	if (unlikely(!mutex_trylock(&port->tty_sem))) {
-		/*
-		 * must test lock as tty layer wraps calls
-		 * to this function with BKL
-		 */
-		dev_err(&dc->pdev->dev, "Would have deadlocked - "
-			"return EAGAIN\n");
-		return -EAGAIN;
-	}
+	mutex_lock(&port->tty_sem);
 
 	if (unlikely(!port->port.count)) {
 		DBG1(" ");
@@ -1741,25 +1733,23 @@ static int ntty_write(struct tty_struct *tty, const unsigned char *buffer,
  * This method is called by the upper tty layer.
  *   #according to sources N_TTY.c it expects a value >= 0 and
  *    does not check for negative values.
+ *
+ * If the port is unplugged report lots of room and let the bits
+ * dribble away so we don't block anything.
  */
 static int ntty_write_room(struct tty_struct *tty)
 {
 	struct port *port = tty->driver_data;
-	int room = 0;
+	int room = 4096;
 	const struct nozomi *dc = get_dc_by_tty(tty);
 
-	if (!dc || !port)
-		return 0;
-	if (!mutex_trylock(&port->tty_sem))
-		return 0;
-
-	if (!port->port.count)
-		goto exit;
-
-	room = port->fifo_ul.size - kfifo_len(&port->fifo_ul);
-
-exit:
-	mutex_unlock(&port->tty_sem);
+	if (dc) {
+		mutex_lock(&port->tty_sem);
+		if (port->port.count)
+			room = port->fifo_ul.size -
+					kfifo_len(&port->fifo_ul);
+		mutex_unlock(&port->tty_sem);
+	}
 	return room;
 }