[linux-usb-devel] [PATCH] USB Serial core fix

[Greg KH]

Hi,

Here's a patch against 2.4.9-ac13 that fixes a long standing bug with
the module use count of the usb-serial core.  If after applying this
patch, anyone has a problem of the usbserial module usage being wrong,
please let me know.  Users of the pl2303 usb-serial driver really need
this patch :)

thanks,

greg k-h

diff -Nru a/drivers/usb/serial/usbserial.c b/drivers/usb/serial/usbserial.c
--- a/drivers/usb/serial/usbserial.c    Fri Sep 21 16:35:05 2001
+++ b/drivers/usb/serial/usbserial.c    Fri Sep 21 16:35:05 2001
@@ -505,8 +505,6 @@
                return -ENODEV;
        }
 
-       MOD_INC_USE_COUNT;
-       
        /* set up our port structure making the tty driver remember our port object, 
and us it */
        portNumber = MINOR(tty->device) - serial->minor;
        port = &serial->port[portNumber];
@@ -544,8 +542,6 @@
        } else {
                generic_close(port, filp);
        }
-
-       MOD_DEC_USE_COUNT;
 }      
 
 
@@ -768,7 +764,10 @@
        if (port_paranoia_check (port, __FUNCTION__))
                return -ENODEV;
 
-       MOD_INC_USE_COUNT;
+       /* only increment our usage count, if this device is _really_ a generic device 
+*/
+       if ((serial->dev->descriptor.idVendor == vendor) &&
+           (serial->dev->descriptor.idProduct == product))
+               MOD_INC_USE_COUNT;
 
        dbg(__FUNCTION__ " - port %d", port->number);
 
@@ -828,7 +827,11 @@
        }
 
        up (&port->sem);
-       MOD_DEC_USE_COUNT;
+
+       /* only decrement our usage count, if this device is _really_ a generic device 
+*/
+       if ((serial->dev->descriptor.idVendor == vendor) &&
+           (serial->dev->descriptor.idProduct == product))
+               MOD_DEC_USE_COUNT;
 }