* with -EINVAL. If there is more than one entry with the same address,
* because it searches the list from end to beginning, it will unregister the
* last one to be registered first (FILO- First In Last Out).
* with -EINVAL. If there is more than one entry with the same address,
* because it searches the list from end to beginning, it will unregister the
* last one to be registered first (FILO- First In Last Out).
* at the same time, because another driver could have unregistered a callback
* between the submissions creating a gap earlier in the list, which would
* be filled first at submission time.
* at the same time, because another driver could have unregistered a callback
* between the submissions creating a gap earlier in the list, which would
* be filled first at submission time.