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

[Jason Wang]

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?