Re: [RFC PATCH 01/10] vdpa: add get_config_size callback in vdpa_config_ops

[Jason Wang <jasowang@redhat.com>]

On 2021/3/2 10:15 下午, Stefano Garzarella wrote:
> On Tue, Mar 02, 2021 at 12:14:13PM +0800, Jason Wang wrote:
>>
>> On 2021/2/16 5:44 下午, Stefano Garzarella wrote:
>>> This new callback is used to get the size of the configuration space
>>> of vDPA devices.
>>>
>>> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
>>> ---
>>>  include/linux/vdpa.h              | 4 ++++
>>>  drivers/vdpa/ifcvf/ifcvf_main.c   | 6 ++++++
>>>  drivers/vdpa/mlx5/net/mlx5_vnet.c | 6 ++++++
>>>  drivers/vdpa/vdpa_sim/vdpa_sim.c  | 9 +++++++++
>>>  4 files changed, 25 insertions(+)
>>>
>>> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
>>> index 4ab5494503a8..fddf42b17573 100644
>>> --- a/include/linux/vdpa.h
>>> +++ b/include/linux/vdpa.h
>>> @@ -150,6 +150,9 @@ struct vdpa_iova_range {
>>>   * @set_status:            Set the device status
>>>   *                @vdev: vdpa device
>>>   *                @status: virtio device status
>>> + * @get_config_size:        Get the size of the configuration space
>>> + *                @vdev: vdpa device
>>> + *                Returns size_t: configuration size
>>
>>
>> Rethink about this, how much we could gain by introducing a dedicated 
>> ops here? E.g would it be simpler if we simply introduce a 
>> max_config_size to vdpa device?
>
> Mainly because in this way we don't have to add new parameters to the 
> vdpa_alloc_device() function.
>
> We do the same for example for 'get_device_id', 'get_vendor_id', 
> 'get_vq_num_max'. All of these are usually static, but we have ops.
> I think because it's easier to extend.
>
> I don't know if it's worth adding a new structure for these static 
> values at this point, like 'struct vdpa_config_params'.


Yes, that's the point. I think for any static values, it should be set 
during device allocation.

I'm fine with both.

Thanks


>
> Thanks,
> Stefano
>

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