On Sat, 21 Apr 2012, Ming Lei wrote: > >> Think about what happens if the URB being unlinked hasn't been > >> presented to the hardware yet. �Once it has been removed from the HCD's > >> internal lists, there's no reason not to give it back right away. �And > >> there's no natural time to give it back later. > > > > Now. The question is not when, but from which context. > > The context should be uniform, so that the requirements > > for locking should also be uniform. > > How about always scheduling a tasklet to run what usb_unlink_urb does? > just implement usb_unlink_urb as something like > tasklet_schedule(unlink_tasklet). > > Then we can have a uniform lock requirement and no changes are involved > on host controller drivers. The return values would not be correct. On the other hand, usbnet could call usb_unlink_urb from within a tasklet. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
