Re: [PATCH mptcp-net 2/3] mptcp: update local address flags when setting it

[Matthieu Baerts <matttbe@kernel.org>]

Hi Geliang,

On 05/11/2024 10:40, Geliang Tang wrote:
> From: Geliang Tang <tanggeliang@kylinos.cn>
> 
> Just like in-kernel pm, when userspace pm does set_flags, it needs to send
> out MP_PRIO signal, and also modify the flags of the corresponding address
> entry in the local address list. This patch implements the missing logic.
> 
> Use mptcp_userspace_pm_lookup_addr() helper to find the address entry on
> userspace_pm_local_addr_list, if bkup is true, set the flags of the address
> entry with FLAG_BACKUP, otherwise, clear FLAG_BACKUP.
> 
> Fixes: 892f396c8e68 ("mptcp: netlink: issue MP_PRIO signals from userspace PMs")
> Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
> ---
>  net/mptcp/pm_userspace.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
> index 9c622b0e3e6e..0c0f6f65accb 100644
> --- a/net/mptcp/pm_userspace.c
> +++ b/net/mptcp/pm_userspace.c
> @@ -562,6 +562,7 @@ int mptcp_userspace_pm_set_flags(struct sk_buff *skb, struct genl_info *info)
>  	struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
>  	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
>  	struct net *net = sock_net(skb->sk);
> +	struct mptcp_pm_addr_entry *entry;
>  	struct mptcp_sock *msk;
>  	int ret = -EINVAL;
>  	struct sock *sk;
> @@ -603,6 +604,16 @@ int mptcp_userspace_pm_set_flags(struct sk_buff *skb, struct genl_info *info)
>  	if (loc.flags & MPTCP_PM_ADDR_FLAG_BACKUP)
>  		bkup = 1;
>  
> +	spin_lock_bh(&msk->pm.lock);
> +	entry = mptcp_userspace_pm_lookup_addr(msk, &loc.addr);

(Linked to my comment from the previous patch) Adding only the helper,
and squashing that in this patch here might be an option, but even that
can cause conflicts.

I think the simplest is not to add this small helper only used once for
the moment: so simply calling list_for_each_entry() here, and add the
following code inside it. WDYT?

> +	if (entry) {
> +		if (bkup)
> +			entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
> +		else
> +			entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP;
> +	}
> +	spin_unlock_bh(&msk->pm.lock);
> +
>  	lock_sock(sk);
>  	ret = mptcp_pm_nl_mp_prio_send_ack(msk, &loc.addr, &rem.addr, bkup);
>  	release_sock(sk);

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.