Messages in this thread | | | From | Duncan Sands <> | Subject | Re: [linux-usb-devel] [PATCH 7/9] USB usbfs: destroy submitted urbs only on the disconnected interface | Date | Wed, 14 Apr 2004 19:09:29 +0200 |
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> On Wed, 14 Apr 2004, Duncan Sands wrote: > > diff -Nru a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c > > --- a/drivers/usb/core/devio.c Wed Apr 14 12:18:20 2004 > > +++ b/drivers/usb/core/devio.c Wed Apr 14 12:18:20 2004 > > @@ -341,6 +341,7 @@ > > static void driver_disconnect(struct usb_interface *intf) > > { > > struct dev_state *ps = usb_get_intfdata (intf); > > + unsigned int ifnum = intf->altsetting->desc.bInterfaceNumber; > > > > if (!ps) > > return; > > @@ -349,11 +350,12 @@ > > * all pending I/O requests; 2.6 does that. > > */ > > > > - clear_bit(intf->cur_altsetting->desc.bInterfaceNumber, &ps->ifclaimed); > > + if (ifnum < 8*sizeof(ps->ifclaimed)) > > + clear_bit(ifnum, &ps->ifclaimed); > > usb_set_intfdata (intf, NULL); > > > > /* force async requests to complete */ > > - destroy_all_async (ps); > > + destroy_async_on_interface(ps, ifnum); > > } > > > > struct usb_driver usbdevfs_driver = { > > Quite apart from the stylistic questions about sanity tests and so on, > this code contains a bug. It wasn't introduced by your patch; it was > there from before and I should have caught it earlier, along with a few > others.
Hi Alan, it was introduced after your last devio.c fixes by the patch "fix xsane breakage, hangs on device scan at launch" by someone who will remain nameless :)
> The real problem is that the code in devio.c doesn't make a clear visual > distinction between interface number (i.e., desc.bInterfaceNumber) and > interface index (i.e., dev->actconfig->interface[index]). The two values > do not have to agree. > > The claimintf(), releaseintf(), and checkintf() routines take an index as > argument, and the ifclaimed bitvector uses the same index. findintfif() > takes a number and returns the corresponding index, duplicating much of > the functionality of usb_ifnum_to_if(). Likewise, findintfep() returns an > index. > > The code here in driver_disconnect() uses a number where it needs to use > an index. > > Similarly, there's a typo in proc_releaseinterface(); the second argument > it passes to releaseintf() should be ret, not intf. > > And in proc_submiturb(), the value stored in as->intf is an index when it > should be an interface number. Or possibly it could remain an index, but > then the value passed to destroy_async_on_interface() by > proc_releaseinterface() should be the index and not the number.
Good catch! I guess the index and the interface differ because interfaces are not always consecutively numbered. Is that right? When can it happen?
Thanks,
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