> I've read them. They are, let's say, as yet inconclusive.
> Anyway, the problem is not limited to 2.5; 2.4 is affected as well.
So the question is how to deal with the current BKL usage,
which is purely to address rmmod issues. I don't think
that preventing rmmod is desirable.
> For now all uses of probe/disconnect in usb(dev)fs are full of races,
> some even exist on UP.
> I want to reduce there number as far as possible and provide
> a safe helper for the rest. Unfortunately the BKL issue
> cannot be hidden. I'll include the current version. It even compiles.
I'd rather not see such helpers _change_ the "BKL held" assertion;
better to keep that as an invariant during these routines.
And I'd also rather see these formalized as interface level calls,
internal to usbcore, rather than continue to try to fake them out
as being device level. For example, pass device and interface
index (!= interface number!!) to both calls, letting driver and
priv be implicit (they're stored in the interface).
- Dave
> /**
> * usb_unbind_driver - disconnects a driver from a device
> * @driver: Driver to be disconnected
> * @device: usb device to be disconnected
> * @priv: private pointer passed to device driver
> * Context: BKL held
> *
> * Handles module usage count correctly
> */
>
> void usb_unbind_driver(struct usb_driver *driver, struct usb_device *device, void
>*priv)
> {
> /* as soon as we increase the module use count we drop the BKL
> before that we must not sleep */
> if (driver->owner) {
> __MOD_INC_USE_COUNT(driver->owner);
> unlock_kernel();
> }
> down(&driver->serialize); /* if we sleep here on an umanaged driver
> the holder of the lock guards against
> module unload */
>
> driver->disconnect(device, priv);
>
> up(&driver->serialize);
> if (driver->owner) {
> lock_kernel();
> __MOD_DEC_USE_COUNT(driver->owner);
> }
> }
>
> /**
> * usb_bind_driver - connect a driver to a device's interface
> */
>
> void *usb_bind_driver(struct usb_driver *driver, struct usb_device *dev, unsigned
>int ifnum)
> {
> int i;
> void *private;
> const struct usb_device_id *id;
> struct usb_interface *interface;
>
> if (driver->owner) {
> __MOD_INC_USE_COUNT(driver->owner);
> unlock_kernel();
> }
>
> interface = &dev->actconfig->interface[ifnum];
>
> id = driver->id_table;
> /* new style driver? */
> if (id) {
> for (i = 0; i < interface->num_altsetting; i++) {
> interface->act_altsetting = i;
> id = usb_match_id(dev, interface, id);
> if (id) {
> down(&driver->serialize);
> private = driver->probe(dev,ifnum,id);
> up(&driver->serialize);
> if (private != NULL)
> break;
> }
> }
>
> /* if driver not bound, leave defaults unchanged */
> if (private == NULL)
> interface->act_altsetting = 0;
> } else { /* "old style" driver */
> down(&driver->serialize);
> private = driver->probe(dev, ifnum, NULL);
> up(&driver->serialize);
> }
> if (driver->owner) {
> lock_kernel();
> __MOD_DEC_USE_COUNT(driver->owner);
> }
>
> return private;
> }
>
>
-------------------------------------------------------
This sf.net email is sponsored by:ThinkGeek
Welcome to geek heaven.
http://thinkgeek.com/sf
_______________________________________________
[EMAIL PROTECTED]
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
