于 2012年12月17日 11:08, Alan Stern 写道:
> It is pretty much as I explained in my previous email.
>
> finish_urb calls usb_free_priv while holding the lock. Then while
> still holding the lock, it calls usb_hcd_unlink_urb_from_ep.
>
> In addition, ohci_urb_dequeue calls usb_hcd_check_unlink_urb while
> holding the lock, and does nothing if the return value is nonzero.
>
> So all you need to do is verify that after usb_hcd_unlink_urb_from_ep
> runs, usb_hcd_check_unlink_urb will always return a nonzero value. In
> fact, it will return -EIDRM -- until the next time the URB is submitted
> and usb_hcd_link_urb_to_ep is called.
it is true for ohci_urb_dequeue.
how about finish_unlinks and takeback_td in drives/usb/host/ohci-q.c ?
(they also can call finish_urb).
--
Chen Gang
Asianux Corporation
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