Provided by: linux-doc-2.6.15_2.6.15-23.39_all
usb_kill_urb - cancel a transfer request and wait for it to finish
void usb_kill_urb (struct urb * urb);
urb pointer to URB describing a previously submitted request, may be
This routine cancels an in-progress request. It is guaranteed that upon
return all completion handlers will have finished and the URB will be
totally idle and available for reuse. These features make this an ideal
way to stop I/O in a disconnect callback or close function. If the
request has not already finished or been unlinked the completion
handler will see urb->status == -ENOENT.
While the routine is running, attempts to resubmit the URB will fail
with error -EPERM. Thus even if the URB’s completion handler always
tries to resubmit, it will not succeed and the URB will become idle.
This routine may not be used in an interrupt context (such as a bottom
half or a completion handler), or when holding a spinlock, or in other
situations where the caller can’t schedule.