Re: [RFC v5 09/11] [media] vb2: add infrastructure to support out-fences

[Alexandre Courbot <acourbot@chromium.org>]

On Friday, November 17, 2017 4:19:00 PM JST, Alexandre Courbot wrote:
> On Thursday, November 16, 2017 2:10:55 AM JST, Gustavo Padovan wrote:
>> From: Gustavo Padovan <gustavo.padovan@collabora.com>
>> 
>> Add vb2_setup_out_fence() and the needed members to struct vb2_buffer.
>> 
>> v3:
>> 	- Do not hold yet another ref to the out_fence (Brian Starkey)
>> 
>> v2:	- change it to reflect fd_install at DQEVENT ...
>
> out_fence_fd is allocated in this patch but not used anywhere 
> for the moment.
> For consistency, maybe move its allocation to the next patch, 
> or move the call
> to fd_install() here if that is possible? In both cases, the 
> call to get_unused_fd() can be moved right before fd_install() 
> so you don't need to
> call put_unused_fd() in the error paths below.

Aha, just realized that fd_install() was called in qbuf() :) Other comments 
probably still hold though.

>
> ... same thing for sync_file too. Maybe this patch can just be merged into
> the next one? The current patch just creates an incomplete 
> version of vb2_setup_out_fence() for which no user exist yet.
>
>> +
>> +	vb->out_fence = vb2_fence_alloc(q->out_fence_context);
>> +	if (!vb->out_fence) {
>> +		put_unused_fd(vb->out_fence_fd);
>> +		return -ENOMEM; ...
>
>