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

On Tue, Mar 18, 2025 at 1:53 AM Paolo Abeni pabeni@redhat.com 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().