Re: [PATCH net-next v7 4/9] net: devmem: Implement TX path

[Mina Almasry]

On Tue, Mar 18, 2025 at 1:53 AM Paolo Abeni <pabeni@xxxxxxxxxx> wrote:
>
> Adding Kuniyuki.
>
> On 3/8/25 10:40 PM, Mina Almasry wrote:
> > @@ -931,10 +932,67 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
> >       return err;
> >  }
> >
> > -/* stub */
> >  int netdev_nl_bind_tx_doit(struct sk_buff *skb, struct genl_info *info)
> >  {
> > -     return 0;
> > +     struct net_devmem_dmabuf_binding *binding;
> > +     struct list_head *sock_binding_list;
> > +     struct net_device *netdev;
> > +     u32 ifindex, dmabuf_fd;
> > +     struct sk_buff *rsp;
> > +     int err = 0;
> > +     void *hdr;
> > +
> > +     if (GENL_REQ_ATTR_CHECK(info, NETDEV_A_DEV_IFINDEX) ||
> > +         GENL_REQ_ATTR_CHECK(info, NETDEV_A_DMABUF_FD))
> > +             return -EINVAL;
> > +
> > +     ifindex = nla_get_u32(info->attrs[NETDEV_A_DEV_IFINDEX]);
> > +     dmabuf_fd = nla_get_u32(info->attrs[NETDEV_A_DMABUF_FD]);
> > +
> > +     sock_binding_list = genl_sk_priv_get(&netdev_nl_family,
> > +                                          NETLINK_CB(skb).sk);
> > +     if (IS_ERR(sock_binding_list))
> > +             return PTR_ERR(sock_binding_list);
> > +
> > +     rsp = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
> > +     if (!rsp)
> > +             return -ENOMEM;
> > +
> > +     hdr = genlmsg_iput(rsp, info);
> > +     if (!hdr) {
> > +             err = -EMSGSIZE;
> > +             goto err_genlmsg_free;
> > +     }
> > +
> > +     rtnl_lock();
>
> The above could possibly be a rtnl_net_lock(), right?
>
> (not strictily related to this series) The same for the existing
> rtnl_lock() call in netdev-genl.c, right?
>

Actually I think this can follow the example set in commit
1d22d3060b9b ("net: drop rtnl_lock for queue_mgmt operations") and
take the netdev_get_by_index_lock().


-- 
Thanks,
Mina