Re: [PATCH v5 02/20] job.h: categorize fields in struct Job

[Emanuele Giuseppe Esposito]

On 10/02/2022 18:35, Stefan Hajnoczi wrote:
> On Thu, Feb 10, 2022 at 05:26:52PM +0100, Emanuele Giuseppe Esposito wrote:
>>
>>
>> On 10/02/2022 16:40, Stefan Hajnoczi wrote:
>>> On Tue, Feb 08, 2022 at 09:34:55AM -0500, Emanuele Giuseppe Esposito wrote:
>>>> Categorize the fields in struct Job to understand which ones
>>>> need to be protected by the job mutex and which don't.
>>>>
>>>> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
>>>> ---
>>>>  include/qemu/job.h | 59 ++++++++++++++++++++++++++--------------------
>>>>  1 file changed, 34 insertions(+), 25 deletions(-)
>>>>
>>>> diff --git a/include/qemu/job.h b/include/qemu/job.h
>>>> index d1192ffd61..86ec46c09e 100644
>>>> --- a/include/qemu/job.h
>>>> +++ b/include/qemu/job.h
>>>> @@ -40,27 +40,50 @@ typedef struct JobTxn JobTxn;
>>>>   * Long-running operation.
>>>>   */
>>>>  typedef struct Job {
>>>> +
>>>> +    /* Fields set at initialization (job_create), and never modified */
>>>
>>> Is there a corresponding "Field protected by job_mutex" comment that
>>> separates fields that need locking?
>>>
>>
>> That would be the comment
>>
>>     /** Protected by job_mutex */
>>
>> situated right after the field "ProgressMeter progress;".
>>
>> Do you want me to change it in "Fields protected by job_mutex"?
> 
> I don't see it:
> 
> +    /** The opaque value that is passed to the completion function.  */
> +    void *opaque;
> +
> +    /* ProgressMeter API is thread-safe */
> +    ProgressMeter progress;
> +
> +
> +    /** AioContext to run the job coroutine in */
> +    AioContext *aio_context;
> +
> +    /** Reference count of the block job */
> +    int refcnt;
> 
> Is it added by a later patch or did I miss it?
> 

Yes sorry I forgot: it is added in patch 19, when the lock is not a nop
anymore.

I think this was suggested in one of the previous reviews, to avoid
having a misleading comment when the fields are not yet protected.

Emanuele