On Sun, 17 Apr 2005, Oliver Neukum wrote: > > Using spin_lock_bh() in enqueue or dequeue isn't a solution because > > existing code already calls these routines with interrupts disabled. > > How so? If you convert the irq code to a tasklet, it'll run in a tasklet.
Yes it will. But it will still disable interrupts before calling completion handlers. It has to; that's a guarantee of the API. So if a completion handler resubmits its URB, that submission will have to be handled with interrupts disabled. Furthermore, there's nothing to prevent USB device drivers from calling usb_submit_urb() or usb_unlink_urb() while they have disabled interrupts for their own reasons. That's a perfectly legal thing to do, but again it means that enqueue and dequeue can be called with interrupts disabled. Alan Stern ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
