Oliver Neukum wrote:
> Am Dienstag, 27. Juni 2006 09:52 schrieb Franck Bui-Huu:
>> + expire = timeout ? msecs_to_jiffies(timeout) : MAX_SCHEDULE_TIMEOUT;
>> + if (!wait_for_completion_timeout(&done, expire)) {
>> + usb_unlink_urb(urb);
>> }
>> -
>> + status = urb->status;
>
> Hm, is this racy?
> What happens if usb_unlink_urb() and the completion handler race?
> If usb_unlink_urb() fails to unlink the URB because it is too late,
> is it guaranteed that urb->status is valid?
> In the old version this could not happen because the completion was
> always done.
well, I'm not sure to understand. Do you mean "what happen if the timeout has
expired, but just before calling usb_unlink_urb() the urb is completed by the
hcd" ?
If so, I think that usb_unlink_urb() handles this case by checking (with lock
held) that the urb is still queued.
Franck
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