linux-kernel - Re: [PATCH net-next v18 20/25] ovpn: implement peer add/get/dump/delete via netlink

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Message-ID: <Z5CwK-xf2uC9cqb3@hog>
Date: Wed, 22 Jan 2025 09:45:31 +0100
From: Sabrina Dubroca <sd@...asysnail.net>
To: Antonio Quartulli <antonio@...nvpn.net>
Cc: netdev@...r.kernel.org, Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Donald Hunter <donald.hunter@...il.com>,
	Shuah Khan <shuah@...nel.org>, ryazanov.s.a@...il.com,
	Andrew Lunn <andrew+netdev@...n.ch>,
	Simon Horman <horms@...nel.org>, linux-kernel@...r.kernel.org,
	linux-kselftest@...r.kernel.org, Xiao Liang <shaw.leon@...il.com>
Subject: Re: [PATCH net-next v18 20/25] ovpn: implement peer
 add/get/dump/delete via netlink

2025-01-22, 00:26:50 +0100, Antonio Quartulli wrote:
> On 20/01/2025 15:52, Antonio Quartulli wrote:
> > On 17/01/2025 12:48, Sabrina Dubroca wrote:
> > [...]
> > > -------- 8< --------
> > > 
> > > diff --git a/drivers/net/ovpn/netlink.c b/drivers/net/ovpn/netlink.c
> > > index 72357bb5f30b..19aa4ee6d468 100644
> > > --- a/drivers/net/ovpn/netlink.c
> > > +++ b/drivers/net/ovpn/netlink.c
> > > @@ -733,6 +733,9 @@ int ovpn_nl_peer_del_doit(struct sk_buff *skb,
> > > struct genl_info *info)
> > >       netdev_dbg(ovpn->dev, "del peer %u\n", peer->id);
> > >       ret = ovpn_peer_del(peer, OVPN_DEL_PEER_REASON_USERSPACE);
> > > +    if (ret >= 0 && peer->sock)
> > > +        wait_for_completion(&peer->sock_detach);
> > > +
> > >       ovpn_peer_put(peer);
> > >       return ret;
> > > diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c
> > > index b032390047fe..6120521d0c32 100644
> > > --- a/drivers/net/ovpn/peer.c
> > > +++ b/drivers/net/ovpn/peer.c
> > > @@ -92,6 +92,7 @@ struct ovpn_peer *ovpn_peer_new(struct ovpn_priv
> > > *ovpn, u32 id)
> > >       ovpn_peer_stats_init(&peer->vpn_stats);
> > >       ovpn_peer_stats_init(&peer->link_stats);
> > >       INIT_WORK(&peer->keepalive_work, ovpn_peer_keepalive_send);
> > > +    init_completion(&peer->sock_detach);
> > >       ret = dst_cache_init(&peer->dst_cache, GFP_KERNEL);
> > >       if (ret < 0) {
> > > diff --git a/drivers/net/ovpn/peer.h b/drivers/net/ovpn/peer.h
> > > index 7a062cc5a5a4..8c54bf5709ef 100644
> > > --- a/drivers/net/ovpn/peer.h
> > > +++ b/drivers/net/ovpn/peer.h
> > > @@ -112,6 +112,7 @@ struct ovpn_peer {
> > >       struct rcu_head rcu;
> > >       struct work_struct remove_work;
> > >       struct work_struct keepalive_work;
> > > +    struct completion sock_detach;
> > >   };
> > >   /**
> > > diff --git a/drivers/net/ovpn/socket.c b/drivers/net/ovpn/socket.c
> > > index a5c3bc834a35..7cefac42c3be 100644
> > > --- a/drivers/net/ovpn/socket.c
> > > +++ b/drivers/net/ovpn/socket.c
> > > @@ -31,6 +31,8 @@ static void ovpn_socket_release_kref(struct kref *kref)
> > >       sockfd_put(sock->sock);
> > >       kfree_rcu(sock, rcu);
> > > +
> > > +    complete(&sock->peer->sock_detach);
> 
> I am moving this line to ovpn_socket_put(), right after kref_put() so that
> every peer going through the socket release will get their complete()
> invoked.
> 
> If the peer happens to be the last one owning the socket, kref_put() will
> first do the detach and only then complete() gets called.
> 
> This requires ovpn_socket_release/put() to take the peer as argument, but
> that's ok.
> 
> This way we should achieve what we needed.

This seems like it would, thanks.

-- 
Sabrina