Re: [Qemu-devel] [PATCH v9 05/10] move out net queue structs define

[Yang Hongyang <yanghy@cn.fujitsu.com>]

On 09/07/2015 05:11 PM, Stefan Hajnoczi wrote:
> On Mon, Sep 07, 2015 at 03:37:20PM +0800, Yang Hongyang wrote:
>> Hi Stefan,
>>
>> On 09/04/2015 06:32 PM, Stefan Hajnoczi wrote:
>> [...]
>>>
>>> net/queue.c has logic to send/queue/flush packets but a
>>> qemu_deliver_packet() call is hardcoded.
>>>
>>> Maybe you can extend qemu_new_net_queue() like this:
>>>
>>> /* Returns:
>>>   *   >0 - success
>>>   *    0 - queue packet for future redelivery
>>>   *   <0 - failure (discard packet)
>>>   */
>>> typedef ssize_t NetQueueDeliverFunc(NetClientState *sender,
>>>                                      unsigned flags,
>>> 				    const struct iovec *iov,
>>> 				    int iovcnt,
>>> 				    void *opaque);
>>>
>>> NetQueue *qemu_new_net_queue(NetQueueDeliverFunc deliver,
>>>                               void *opaque);
>>>
>>> Now net/net.c:qemu_net_client_setup() needs to call:
>>>
>>>    nc->incoming_queue = qemu_new_net_queue(qemu_deliver_packet_iov, nc);
>>>
>>> And the filter code can use qemu_net_queue_send_iov() and
>>> qemu_net_queue_flush().  The filter just needs to provide its own
>>> NetQueueDeliveryFunc.
>>>
>>> I haven't checked the details (e.g. non-iov delivery, etc) but the idea
>>> is to use the net/queue.c API instead of duplicating similar logic in
>>> the filter code.
>>
>> Thanks very much for the suggestion, I've already implemented it and tested,
>> the code looks cleaner now.
>>
>> The last issue is the QOM thing, do Markus and Andreas have more input
>> about that?
>
> If you would like to see examples of QOM usage, take a look at
> iothread.c and/or backends/hostmem.c.
>
> The key things are:
>
> 1. They use include/qom/object.h to register a type based on
>     TYPE_OBJECT and their properties are registered using
>     object_property_add_*().
>
> 2. They implement the TYPE_USER_CREATABLE interface so the -object
>     command-line option can be used to instantiate them.  See
>     object_interfaces.h.
>
> As a result, a lot of code becomes unnecessary and iothread.c, in
> particular, is quite short.

Thanks a lot, this is what I need, will look into this and rebase this
series on top of QOM.

>
> Stefan
> .
>

-- 
Thanks,
Yang.