Re: [net/devlink] Question about possible CMD misuse in devlink_nl_port_new_doit()

[Jiri Pirko <jiri@resnulli.us>]

Sun, Mar 17, 2024 at 03:57:19AM CET, chenyuan0y@gmail.com wrote:
>Dear Devlink Developers,
>
>We are curious whether the function `devlink_nl_port_new_doit()` might have a incorrect command value `DEVLINK_CMD_NEW`, which should be `DEVLINK_CMD_PORT_NEW`.
>
>The function is https://elixir.bootlin.com/linux/v6.8/source/net/devlink/port.c#L844
>and the relevant code is
>```
>int devlink_nl_port_new_doit(struct sk_buff *skb, struct genl_info *info)
>{
>	...
>	err = devlink_nl_port_fill(msg, devlink_port, DEVLINK_CMD_NEW,
>				   info->snd_portid, info->snd_seq, 0, NULL);
>	if (WARN_ON_ONCE(err))
>		goto err_out_msg_free;
>	...
>}
>```
>
>In `devlink_nl_port_fill`, all other places use `DEVLINK_CMD_PORT_NEW` as the command value. However, in `devlink_nl_port_new_doit`, it uses `DEVLINK_CMD_NEW`. This might be a misuse, also according to https://lore.kernel.org/netdev/20240216113147.50797-1-jiri@resnulli.us/T/.
>
>Based on our understanding, a possible fix would be
>```
>-  err = devlink_nl_port_fill(msg, devlink_port, DEVLINK_CMD_NEW,
>+  err = devlink_nl_port_fill(msg, devlink_port, DEVLINK_CMD_PORT_NEW,
>```
>
>Please kindly correct us if we missed any key information. Looking forward to your response!

You are correct, this is a bug. Thanks for report!
Here's the fix:
https://lore.kernel.org/netdev/20240318091908.2736542-1-jiri@resnulli.us/