tty: Fix the digi acceleport driver NULL checks

This now refcounts but doesn't actually check the reference was obtained in
all the places it should.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 9 insertions, 5 deletions

diff --git a/drivers/usb/serial/digi_acceleport.c b/drivers/usb/serial/digi_acceleport.c
index fd35f73b5721..b92070c103cd 100644
--- a/drivers/usb/serial/digi_acceleport.c
+++ b/drivers/usb/serial/digi_acceleport.c
@@ -609,8 +609,10 @@ static void digi_wakeup_write_lock(struct work_struct *work)
 static void digi_wakeup_write(struct usb_serial_port *port)
 {
         struct tty_struct *tty = tty_port_tty_get(&port->port);
-        tty_wakeup(tty);
-        tty_kref_put(tty);
+        if (tty) {
+                tty_wakeup(tty);
+                tty_kref_put(tty);
+        }
 }
 
 
@@ -1682,7 +1684,7 @@ static int digi_read_inb_callback(struct urb *urb)
                 priv->dp_throttle_restart = 1;
 
         /* receive data */
-        if (opcode == DIGI_CMD_RECEIVE_DATA) {
+        if (tty && opcode == DIGI_CMD_RECEIVE_DATA) {
                 /* get flag from port_status */
                 flag = 0;
 
@@ -1763,10 +1765,12 @@ static int digi_read_oob_callback(struct urb *urb)
                         return -1;
 
                 tty = tty_port_tty_get(&port->port);
+
                 rts = 0;
-                rts = tty->termios->c_cflag & CRTSCTS;
+                if (tty)
+                        rts = tty->termios->c_cflag & CRTSCTS;
                 
-                if (opcode == DIGI_CMD_READ_INPUT_SIGNALS) {
+                if (tty && opcode == DIGI_CMD_READ_INPUT_SIGNALS) {
                         spin_lock(&priv->dp_port_lock);
                         /* convert from digi flags to termiox flags */
                         if (val & DIGI_READ_INPUT_SIGNALS_CTS) {