[PATCH v2 14/15] USB: ssu100: fix TIOCMIWAIT and disconnect

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Make sure to wake up any process sleeping on the modem-status-change
queue at port remove.

Currently a process waiting on modem status changes will not necessarily
be woken on device disconnect.

Note that we need to use the disconnected flag to detect disconnect as
the port private data may have been freed when woken up.

Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx>
---
 drivers/usb/serial/ssu100.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/serial/ssu100.c b/drivers/usb/serial/ssu100.c
index b57cf84..8891203 100644
--- a/drivers/usb/serial/ssu100.c
+++ b/drivers/usb/serial/ssu100.c
@@ -356,7 +356,8 @@ static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
 
 	while (1) {
 		wait_event_interruptible(priv->delta_msr_wait,
-					 ((priv->icount.rng != prev.rng) ||
+					 (port->serial->disconnected ||
+					  (priv->icount.rng != prev.rng) ||
 					  (priv->icount.dsr != prev.dsr) ||
 					  (priv->icount.dcd != prev.dcd) ||
 					  (priv->icount.cts != prev.cts)));
@@ -364,16 +365,13 @@ static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
 		if (signal_pending(current))
 			return -ERESTARTSYS;
 
+		if (port->serial->disconnected)
+			return -EIO;
+
 		spin_lock_irqsave(&priv->status_lock, flags);
 		cur = priv->icount;
 		spin_unlock_irqrestore(&priv->status_lock, flags);
 
-		if ((prev.rng == cur.rng) &&
-		    (prev.dsr == cur.dsr) &&
-		    (prev.dcd == cur.dcd) &&
-		    (prev.cts == cur.cts))
-			return -EIO;
-
 		if ((arg & TIOCM_RNG && (prev.rng != cur.rng)) ||
 		    (arg & TIOCM_DSR && (prev.dsr != cur.dsr)) ||
 		    (arg & TIOCM_CD  && (prev.dcd != cur.dcd)) ||
@@ -457,6 +455,7 @@ static int ssu100_port_remove(struct usb_serial_port *port)
 	struct ssu100_port_private *priv;
 
 	priv = usb_get_serial_port_data(port);
+	wake_up_interruptible(&priv->delta_msr_wait);
 	kfree(priv);
 
 	return 0;
-- 
1.8.1.1

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