Re: [Qemu-block] [RFC patch 3/3] blockjob: add devops to blockjob backends

[Paolo Bonzini]

On 16/03/2017 01:46, John Snow wrote:
> - BlkDevOps is traditionally only for Qdev devices, and a BlockJob is not
>   currently a 'device'... Do we want to loosen this restriction, find another
>   way to deliver callbacks to BlockJobs attached to BlkBackends, or do 
> something
>   crazy like make a BlockJob device object?
> 
>   struct JobDevice {
>     DeviceState parent_obj;
>     BlockJob *job;
>   } ...??

I think we want to loosen it.

> - Not so sure about leaving the initial job refcount at 1, since we are giving
>   away a handle to this job as dev_opaque. By incrementing it to 2, however,
>   it's not clear whose responsibility it is to decrement it again.

It would be another callback, sent at the time the dev_ops are removed.
But devices have been treating dev_opaque as a weak reference, it makes
sense to do the same for jobs.

Paolo