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

[Yang Hongyang]

On 09/01/2015 10:43 PM, Stefan Hajnoczi wrote:
> On Tue, Sep 01, 2015 at 05:06:18PM +0800, Yang Hongyang wrote:
> > This will be used by the next patch in this series.
> >
> > Signed-off-by: Yang Hongyang <address@hidden>
> > Reviewed-by: Thomas Huth <address@hidden>
> > ---
> >   include/net/queue.h | 19 +++++++++++++++++++
> >   net/queue.c         | 19 -------------------
> >   2 files changed, 19 insertions(+), 19 deletions(-)
> >
> > diff --git a/include/net/queue.h b/include/net/queue.h
> > index fc02b33..1d65e47 100644
> > --- a/include/net/queue.h
> > +++ b/include/net/queue.h
> > @@ -31,6 +31,25 @@ typedef struct NetQueue NetQueue;
> >
> >   typedef void (NetPacketSent) (NetClientState *sender, ssize_t ret);
> >
> > +struct NetPacket {
> > +    QTAILQ_ENTRY(NetPacket) entry;
> > +    NetClientState *sender;
> > +    unsigned flags;
> > +    int size;
> > +    NetPacketSent *sent_cb;
> > +    uint8_t data[0];
> > +};
> > +
> > +struct NetQueue {
> > +    void *opaque;
> > +    uint32_t nq_maxlen;
> > +    uint32_t nq_count;
> > +
> > +    QTAILQ_HEAD(packets, NetPacket) packets;
> > +
> > +    unsigned delivering:1;
> > +};
> > +
>
> Why is it necessary to expose both structs?

In next patch, we add a API to pass the packet to next filter:
ssize_t qemu_netfilter_pass_to_next(NetFilterState *nf, NetPacket *packet);
which will access the internals of NetPacket.

and in buffer filter, we need the NetQueue to Queue packets, and also to
access queue->packets(pass this packets to next filter).

> Normally functions would be added to maintain the abstraction.  Instead,
> you have chosen to access the fields directly - this is probably a bad
> idea.
> .

--
Thanks,
Yang.