USB: serial: sierra driver sierra_calc_num_ports() fix

- Removed potential kernel oops from sierra_calc_num_ports() function.
  Calling this function twice would likely have caused an oops because
  the function releases allocated memory after the first call.
- Modified sierra_probe() function to reflect the changes in
  sierra_calc_num_ports().

Signed-off-by: Elina Pasheva <epasheva@sierrawireless.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c
index bcfe0ac1e2211921c2c6cf240a6eba11cf7fc011..f047ab5fa97b1b2c69a9aaf38ef7f84779c6e8c2 100644 (file)
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -83,18 +83,22 @@ static int sierra_vsc_set_nmea(struct usb_device *udev, __u16 enable)
 
 static int sierra_calc_num_ports(struct usb_serial *serial)
 {
-       int result;
-       int *num_ports = usb_get_serial_data(serial);
-       dev_dbg(&serial->dev->dev, "%s\n", __func__);
+       int num_ports = 0;
+       u8 ifnum, numendpoints;
 
-       result = *num_ports;
+       dev_dbg(&serial->dev->dev, "%s\n", __func__);
 
-       if (result) {
-               kfree(num_ports);
-               usb_set_serial_data(serial, NULL);
-       }
+       ifnum = serial->interface->cur_altsetting->desc.bInterfaceNumber;
+       numendpoints = serial->interface->cur_altsetting->desc.bNumEndpoints;
 
-       return result;
+       /* Dummy interface present on some SKUs should be ignored */
+       if (ifnum == 0x99)
+               num_ports = 0;
+       else if (numendpoints <= 3)
+               num_ports = 1;
+       else
+               num_ports = (numendpoints-1)/2;
+       return num_ports;
 }
 
 static int is_blacklisted(const u8 ifnum,
@@ -140,23 +144,12 @@ static int sierra_probe(struct usb_serial *serial,
 {
        int result = 0;
        struct usb_device *udev;
-       int *num_ports;
        u8 ifnum;
-       u8 numendpoints;
-
-       dev_dbg(&serial->dev->dev, "%s\n", __func__);
 
-       num_ports = kmalloc(sizeof(*num_ports), GFP_KERNEL);
-       if (!num_ports)
-               return -ENOMEM;
-
-       ifnum = serial->interface->cur_altsetting->desc.bInterfaceNumber;
-       numendpoints = serial->interface->cur_altsetting->desc.bNumEndpoints;
        udev = serial->dev;
+       dev_dbg(&udev->dev, "%s\n", __func__);
 
-       /* Figure out the interface number from the serial structure */
        ifnum = sierra_calc_interface(serial);
-
        /*
         * If this interface supports more than 1 alternate
         * select the 2nd one
@@ -168,20 +161,6 @@ static int sierra_probe(struct usb_serial *serial,
                usb_set_interface(udev, ifnum, 1);
        }
 
-       /* Dummy interface present on some SKUs should be ignored */
-       if (ifnum == 0x99)
-               *num_ports = 0;
-       else if (numendpoints <= 3)
-               *num_ports = 1;
-       else
-               *num_ports = (numendpoints-1)/2;
-
-       /*
-        * save off our num_ports info so that we can use it in the
-        * calc_num_ports callback
-        */
-       usb_set_serial_data(serial, (void *)num_ports);
-
        /* ifnum could have changed - by calling usb_set_interface */
        ifnum = sierra_calc_interface(serial);