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Date:   Thu, 16 Jul 2020 13:25:33 +0300
From:   Eli Cohen <eli@mellanox.com>
To:     Jason Wang <jasowang@redhat.com>
Cc:     mst@redhat.com, virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org, shahafs@mellanox.com,
        saeedm@mellanox.com, Parav Pandit <parav@mellanox.com>
Subject: Re: [PATCH vhost next 06/10] vdpa: Add means to communicate vq
 status on get_vq_state
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On Thu, Jul 16, 2020 at 05:35:18PM +0800, Jason Wang wrote:
> 
> On 2020/7/16 下午4:21, Eli Cohen wrote:
> >On Thu, Jul 16, 2020 at 04:11:00PM +0800, Jason Wang wrote:
> >>On 2020/7/16 下午3:23, Eli Cohen wrote:
> >>>Currently, get_vq_state() is used only to pass the available index value
> >>>of a vq. Extend the struct to return status on the VQ to the caller.
> >>>For now, define VQ_STATE_NOT_READY. In the future it will be extended to
> >>>include other infomration.
> >>>
> >>>Modify current vdpa driver to update this field.
> >>>
> >>>Reviewed-by: Parav Pandit<parav@mellanox.com>
> >>>Signed-off-by: Eli Cohen<eli@mellanox.com>
> >>What's the difference between this and get_vq_ready()?
> >>
> >>Thanks
> >>
> >There is no difference. It is just a way to communicate a problem to
> >with the state of the VQ back to the caller. This is not available now.
> >I think an asynchronous is preferred but that is not available
> >currently.
> 
> 
> I still don't see the reason, maybe you can give me an example?
> 
>

My intention was to provide a mechainsm to return meaningful information
on the state of the vq. For example, when you fail to get the state of
the VQ.

Maybe I could just change the prototype of the function to return int
and the driver could put an error if it has trouble returning the vq
state.