int usb_unlink_urb (struct urb * urb);
This routine cancels an in-progress request. URBs complete only once per submission, and may be canceled only once per submission. Successful cancelation means the requests's completion handler will be called with a status code indicating that the request has been canceled (rather than any other code) and will quickly be removed from host controller data structures.
When the URB_ASYNC_UNLINK transfer flag for the URB is clear, this request is synchronous. Success is indicated by returning zero, at which time the urb will have been unlinked and its completion handler will have been called with urb->status -ENOENT. Failure is indicated by any other return value.
The synchronous cancelation mode may not be used when unlinking an urb from an interrupt context, such as a bottom half or a completion handler; or when holding a spinlock; or in other cases when the caller can't schedule.
When the URB_ASYNC_UNLINK transfer flag for the URB is set, this request is asynchronous. Success is indicated by returning -EINPROGRESS, at which time the urb will normally not have been unlinked. The completion function will see urb->status -ECONNRESET. Failure is indicated by any other return value.
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If you have comments on the formatting of this manpage, then please contact Michael Still (mikal@stillhq.com).
This documentation was generated with kernel version 2.6.0.