On Fri, 2012-11-30 at 15:27 +0000, Thomas Graf wrote:
> On 11/30/12 at 11:00pm, Cong Wang wrote:
> > I don't understand this. nla_put_flag() is used to put a flag (only one
> > bit set) into a netlink message, so why should we use it to put
> > p->port_no here? And why port_no 0 matters here?
>
> nla_put_flag() will simply add a netlink attribute with no payload,
> i.e. just the header. Assuming that port_no == 0 is invalid the
> port_no can be used as attribute id as both are 16bit integers.
>
> It will look like this:
>
> MDBA_ROUTERS = {
> {
> .nla_len = 4,
> .nla_type = <port_no_1>,
> },
> {
> .nla_len = 4,
> .nla_type = <port_no_2>,
> }
> [...]
> }
>
> If you ever need to extend this you can just add payload to the
> per port attribute and nothing will break.
Never mind, I will use port->dev->ifindex instead of port->port_no. This
will also make the user-space easier.
>
> > So I should use net->dev_base_seq + mdb->seq ?
>
> No you can't, mdb->seq is not stable throughout a dump. What you
> can do is save mdb->seq in cb->args[] and in case you continue
> dumping from the same mdb in the next call to your dump function
> you check if it changed and bump cb->seq if it did to trigger an
> interrupt.
Ok, will do.
Thanks!
