USB: ftdi_sio: use port_probe / port_remove thereby fixing access to the latency_timer

Convert all the port specific code in attach / shutdown to use the new
port_probe / port_register callbacks from device_register /
device_unregister allowing adding the sysfs attributes to be added at
the correct time and to the serial port device itself, instead of to
the unadorned usb device, avoiding a NULL dereference.

Signed-off-by: Jim Radford <radford@blackbean.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 35 insertions, 44 deletions

diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 07884e0803b9..ada4e6c6f9cc 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -597,6 +597,8 @@ struct ftdi_private {
 static int  ftdi_sio_probe      (struct usb_serial *serial, const struct usb_device_id *id);
 static int  ftdi_sio_attach             (struct usb_serial *serial);
 static void ftdi_shutdown               (struct usb_serial *serial);
+static int  ftdi_sio_port_probe (struct usb_serial_port *port);
+static int  ftdi_sio_port_remove        (struct usb_serial_port *port);
 static int  ftdi_open                   (struct usb_serial_port *port, struct file *filp);
 static void ftdi_close                  (struct usb_serial_port *port, struct file *filp);
 static int  ftdi_write                  (struct usb_serial_port *port, const unsigned char *buf, int count);
@@ -631,6 +633,8 @@ static struct usb_serial_driver ftdi_sio_device = {
         .num_bulk_out =         1,
         .num_ports =            1,
         .probe =                ftdi_sio_probe,
+        .port_probe =           ftdi_sio_port_probe,
+        .port_remove =          ftdi_sio_port_remove,
         .open =                 ftdi_open,
         .close =                ftdi_close,
         .throttle =             ftdi_throttle,
@@ -1033,11 +1037,10 @@ static ssize_t show_latency_timer(struct device *dev, struct device_attribute *a
 {
         struct usb_serial_port *port = to_usb_serial_port(dev);
         struct ftdi_private *priv = usb_get_serial_port_data(port);
-        struct usb_device *udev;
+        struct usb_device *udev = port->serial->dev;
         unsigned short latency = 0;
         int rv = 0;
 
-        udev = to_usb_device(dev);
 
         dbg("%s",__FUNCTION__);
 
@@ -1061,13 +1064,11 @@ static ssize_t store_latency_timer(struct device *dev, struct device_attribute *
 {
         struct usb_serial_port *port = to_usb_serial_port(dev);
         struct ftdi_private *priv = usb_get_serial_port_data(port);
-        struct usb_device *udev;
+        struct usb_device *udev = port->serial->dev;
         char buf[1];
         int v = simple_strtoul(valbuf, NULL, 10);
         int rv = 0;
 
-        udev = to_usb_device(dev);
-
         dbg("%s: setting latency timer = %i", __FUNCTION__, v);
 
         rv = usb_control_msg(udev,
@@ -1092,13 +1093,11 @@ static ssize_t store_event_char(struct device *dev, struct device_attribute *att
 {
         struct usb_serial_port *port = to_usb_serial_port(dev);
         struct ftdi_private *priv = usb_get_serial_port_data(port);
-        struct usb_device *udev;
+        struct usb_device *udev = port->serial->dev;
         char buf[1];
         int v = simple_strtoul(valbuf, NULL, 10);
         int rv = 0;
 
-        udev = to_usb_device(dev);
-
         dbg("%s: setting event char = %i", __FUNCTION__, v);
 
         rv = usb_control_msg(udev,
@@ -1119,46 +1118,38 @@ static ssize_t store_event_char(struct device *dev, struct device_attribute *att
 static DEVICE_ATTR(latency_timer, S_IWUSR | S_IRUGO, show_latency_timer, store_latency_timer);
 static DEVICE_ATTR(event_char, S_IWUSR, NULL, store_event_char);
 
-static int create_sysfs_attrs(struct usb_serial *serial)
+static int create_sysfs_attrs(struct usb_serial_port *port)
 {
-        struct ftdi_private *priv;
-        struct usb_device *udev;
+        struct ftdi_private *priv = usb_get_serial_port_data(port);
         int retval = 0;
 
         dbg("%s",__FUNCTION__);
 
-        priv = usb_get_serial_port_data(serial->port[0]);
-        udev = serial->dev;
-
         /* XXX I've no idea if the original SIO supports the event_char
          * sysfs parameter, so I'm playing it safe.  */
         if (priv->chip_type != SIO) {
                 dbg("sysfs attributes for %s", ftdi_chip_name[priv->chip_type]);
-                retval = device_create_file(&udev->dev, &dev_attr_event_char);
+                retval = device_create_file(&port->dev, &dev_attr_event_char);
                 if ((!retval) &&
                     (priv->chip_type == FT232BM || priv->chip_type == FT2232C)) {
-                        retval = device_create_file(&udev->dev,
+                        retval = device_create_file(&port->dev,
                                                     &dev_attr_latency_timer);
                 }
         }
         return retval;
 }
 
-static void remove_sysfs_attrs(struct usb_serial *serial)
+static void remove_sysfs_attrs(struct usb_serial_port *port)
 {
-        struct ftdi_private *priv;
-        struct usb_device *udev;
+        struct ftdi_private *priv = usb_get_serial_port_data(port);
 
         dbg("%s",__FUNCTION__);
 
-        priv = usb_get_serial_port_data(serial->port[0]);
-        udev = serial->dev;
-
         /* XXX see create_sysfs_attrs */
         if (priv->chip_type != SIO) {
-                device_remove_file(&udev->dev, &dev_attr_event_char);
+                device_remove_file(&port->dev, &dev_attr_event_char);
                 if (priv->chip_type == FT232BM || priv->chip_type == FT2232C) {
-                        device_remove_file(&udev->dev, &dev_attr_latency_timer);
+                        device_remove_file(&port->dev, &dev_attr_latency_timer);
                 }
         }
 
@@ -1178,13 +1169,9 @@ static int ftdi_sio_probe (struct usb_serial *serial, const struct usb_device_id
         return (0);
 }
 
-/* attach subroutine */
-static int ftdi_sio_attach (struct usb_serial *serial)
+static int ftdi_sio_port_probe(struct usb_serial_port *port)
 {
-        struct usb_serial_port *port = serial->port[0];
         struct ftdi_private *priv;
-        struct ftdi_sio_quirk *quirk;
-        int retval;
 
         dbg("%s",__FUNCTION__);
 
@@ -1224,19 +1211,21 @@ static int ftdi_sio_attach (struct usb_serial *serial)
         kfree(port->bulk_out_buffer);
         port->bulk_out_buffer = NULL;
 
-        usb_set_serial_port_data(serial->port[0], priv);
+        usb_set_serial_port_data(port, priv);
 
-        ftdi_determine_type (serial->port[0]);
-        retval = create_sysfs_attrs(serial);
-        if (retval)
-                dev_err(&serial->dev->dev, "Error creating sysfs files, "
-                        "continuing\n");
+        ftdi_determine_type (port);
+        create_sysfs_attrs(port);
+        return 0;
+}
 
+/* attach subroutine */
+static int ftdi_sio_attach (struct usb_serial *serial)
+{
         /* Check for device requiring special set up. */
-        quirk = (struct ftdi_sio_quirk *)usb_get_serial_data(serial);
-        if (quirk && quirk->setup) {
+        struct ftdi_sio_quirk *quirk = usb_get_serial_data(serial);
+
+        if (quirk && quirk->setup)
                 quirk->setup(serial);
-        }
 
         return 0;
 } /* ftdi_sio_attach */
@@ -1280,17 +1269,18 @@ static void ftdi_HE_TIRA1_setup (struct usb_serial *serial)
  *      calls __serial_close for each open of the port
  *      shutdown is called then (ie ftdi_shutdown)
  */
-
-
 static void ftdi_shutdown (struct usb_serial *serial)
-{ /* ftdi_shutdown */
+{
+        dbg("%s", __FUNCTION__);
+}
 
-        struct usb_serial_port *port = serial->port[0];
+static int ftdi_sio_port_remove(struct usb_serial_port *port)
+{
         struct ftdi_private *priv = usb_get_serial_port_data(port);
 
         dbg("%s", __FUNCTION__);
 
-        remove_sysfs_attrs(serial);
+        remove_sysfs_attrs(port);
 
         /* all open ports are closed at this point
          *    (by usbserial.c:__serial_close, which calls ftdi_close)
@@ -1300,8 +1290,9 @@ static void ftdi_shutdown (struct usb_serial *serial)
                 usb_set_serial_port_data(port, NULL);
                 kfree(priv);
         }
-} /* ftdi_shutdown */
 
+        return 0;
+}
 
 static int  ftdi_open (struct usb_serial_port *port, struct file *filp)
 { /* ftdi_open */