Re: [Qemu-devel] [PATCH] net/net: Add ReadState for reuse codes

[Jason Wang <jasowang@redhat.com>]

On 2016年05月12日 14:33, Zhang Chen wrote:
>>>>> +    ret = net_fill_rstate(&s->rs, buf, size);
>>>>> +
>>>>> +    if (ret == -1) {
>>>>> +        goto eoc;
>>>>> +    } else if (ret == 1) {
>>>>> +        if (qemu_send_packet_async(&s->nc, s->rs.buf,
>>>>> +                                   s->rs.packet_len,
>>>>> + net_socket_send_completed) == 0) {
>>>>> +            net_socket_read_poll(s, false);
>>>>
>>>> This looks not elegant, maybe we could use callback (which was 
>>>> initialized by the helper I mention above) to do this. Any thoughts 
>>>> on this?
>>>
>>> Do you mean:
>>>
>>> remove
>>> +        if (qemu_send_packet_async(&s->nc, s->rs.buf,
>>> +                                   s->rs.packet_len,
>>> +                                   net_socket_send_completed) == 0) {
>>> +            net_socket_read_poll(s, false);
>>>
>>> add
>>>
>>> s->rs->done
>>>
>>> void socket_fill_rsstate_done_cb(SocketReadState *srs, void *opaque)
>>> {
>>>     NetSocketState *s = opaque;
>>>
>>>     if (qemu_send_packet_async(&s->nc, srs->buf,
>>>                                srs->packet_len,
>>>                                net_socket_send_completed) == 0) {
>>>         net_socket_read_poll(s, false);
>>>     }
>>> }
>>
>> Yes, but there's no need for opaque, we can infer the container by 
>> container_of().
>>
>
> But in filter-mirror.c we need do this:
>
>
> void  redirector_fill_rsstate_done_cb(SocketReadState *srs, void *opaque)
> {
>     NetFilterState *nf = opaque;
>
>     redirector_to_filter(nf, srs->buf, srs->packet_len);
> }
>
> so,I think we have to use void *opaque.
>
>
>

You mean you need to get nf? Since SocketReadState were embedded in 
MirrorState, so you could get the address of MirrorState, then it's not 
hard to get nf address?