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

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Message-ID: <10bb8eb7-fdcc-4ab6-8ddb-52491933659e@openvpn.net>
Date: Wed, 22 Jan 2025 00:26:50 +0100
From: Antonio Quartulli <antonio@...nvpn.net>
To: Sabrina Dubroca <sd@...asysnail.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

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.


Regards,


-- 
Antonio Quartulli
OpenVPN Inc.