Re: [PATCH net-next 11/15] mptcp: pm: add id parameter for get_addr

[Simon Horman <horms@kernel.org>]

On Thu, Jan 16, 2025 at 05:51:33PM +0100, Matthieu Baerts (NGI0) wrote:
> From: Geliang Tang <tanggeliang@kylinos.cn>
> 
> The address id is parsed both in mptcp_pm_nl_get_addr() and
> mptcp_userspace_pm_get_addr(), this makes the code somewhat repetitive.
> 
> So this patch adds a new parameter 'id' for all get_addr() interfaces.
> The address id is only parsed in mptcp_pm_nl_get_addr_doit(), then pass
> it to both mptcp_pm_nl_get_addr() and mptcp_userspace_pm_get_addr().
> 
> Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>

...

> diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
> index 853b1ea8680ae753fcb882d8b8f4486519798503..392f91dd21b4ce07efb5f44c701f2261afcdc37e 100644
> --- a/net/mptcp/pm_netlink.c
> +++ b/net/mptcp/pm_netlink.c
> @@ -1773,23 +1773,15 @@ int mptcp_nl_fill_addr(struct sk_buff *skb,
>  	return -EMSGSIZE;
>  }
>  
> -int mptcp_pm_nl_get_addr(struct genl_info *info)
> +int mptcp_pm_nl_get_addr(u8 id, struct genl_info *info)
>  {
>  	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
> -	struct mptcp_pm_addr_entry addr, *entry;
> +	struct mptcp_pm_addr_entry *entry;
>  	struct sk_buff *msg;
>  	struct nlattr *attr;
>  	void *reply;
>  	int ret;
>  
> -	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ENDPOINT_ADDR))
> -		return -EINVAL;
> -
> -	attr = info->attrs[MPTCP_PM_ENDPOINT_ADDR];
> -	ret = mptcp_pm_parse_entry(attr, info, false, &addr);
> -	if (ret < 0)
> -		return ret;
> -

Hi Matthieu and Geliang,

This hunk removes the initialisation of attr...

>  	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
>  	if (!msg)
>  		return -ENOMEM;
> @@ -1803,7 +1795,7 @@ int mptcp_pm_nl_get_addr(struct genl_info *info)
>  	}
>  
>  	rcu_read_lock();
> -	entry = __lookup_addr_by_id(pernet, addr.addr.id);
> +	entry = __lookup_addr_by_id(pernet, id);
>  	if (!entry) {
>  		NL_SET_ERR_MSG_ATTR(info->extack, attr, "address not found");

... but attr is still used here.

Flagged by clang-19 W=1 builds and Smatch.

>  		ret = -EINVAL;

...