Re: [PATCH mptcp-net v2 3/3] mptcp: pm: avoid code duplication to lookup endp

[Geliang Tang <geliang@kernel.org>]

Hi Matt,

Thanks for this patch.

On Fri, 2024-10-25 at 11:32 +0200, Matthieu Baerts (NGI0) wrote:
> From: Geliang Tang <tanggeliang@kylinos.cn>
> 
> The helper __lookup_addr_rcu() can be used in
> mptcp_pm_nl_get_local_id()
> and mptcp_pm_nl_is_backup() to simplify the code, and avoid code
> duplication.
> 
> Co-developed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
> Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
> ---
> Notes:
>  - This is also for -next.
> ---
>  net/mptcp/pm_netlink.c | 20 ++++++--------------
>  1 file changed, 6 insertions(+), 14 deletions(-)
> 
> diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
> index
> f38e1ccd34e95cd88b179a8b50e6965731542871..7c6e664b236d1659a554d003c78
> c72ec91895ba5 100644
> --- a/net/mptcp/pm_netlink.c
> +++ b/net/mptcp/pm_netlink.c
> @@ -1154,17 +1154,13 @@ int mptcp_pm_nl_get_local_id(struct
> mptcp_sock *msk, struct mptcp_addr_info *skc
>  {
>  	struct mptcp_pm_addr_entry *entry;
>  	struct pm_nl_pernet *pernet;
> -	int ret = -1;
> +	int ret;
>  
>  	pernet = pm_nl_get_pernet_from_msk(msk);
>  
>  	rcu_read_lock();
> -	list_for_each_entry_rcu(entry, &pernet->local_addr_list,
> list) {
> -		if (mptcp_addresses_equal(&entry->addr, skc, entry-
> >addr.port)) {
> -			ret = entry->addr.id;
> -			break;
> -		}
> -	}
> +	entry = __lookup_addr_rcu(pernet, skc);
> +	ret = entry ? entry->addr.id : -1;
>  	rcu_read_unlock();
>  	if (ret >= 0)
>  		return ret;
> @@ -1191,15 +1187,11 @@ bool mptcp_pm_nl_is_backup(struct mptcp_sock
> *msk, struct mptcp_addr_info *skc)
>  {
>  	struct pm_nl_pernet *pernet =
> pm_nl_get_pernet_from_msk(msk);
>  	struct mptcp_pm_addr_entry *entry;
> -	bool backup = false;
> +	bool backup;
>  
>  	rcu_read_lock();
> -	list_for_each_entry_rcu(entry, &pernet->local_addr_list,
> list) {
> -		if (mptcp_addresses_equal(&entry->addr, skc, entry-
> >addr.port)) {
> -			backup = !!(entry->flags &
> MPTCP_PM_ADDR_FLAG_BACKUP);
> -			break;
> -		}
> -	}
> +	entry = __lookup_addr_rcu(pernet, skc);
> +	backup = entry && !!(entry->flags &
> MPTCP_PM_ADDR_FLAG_BACKUP);

I think we should check whether entry is NULL here too. No?

-Geliang

>  	rcu_read_unlock();
>  
>  	return backup;
>