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>

1 files changed, 14 insertions, 35 deletions

diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c
index bcfe0ac1e221..f047ab5fa97b 100644
--- 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);