From: Or Gerlitz <ogerlitz@mellanox.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: <hkchu@google.com>, <edumazet@google.com>,
<herbert@gondor.apana.org.au>, <netdev@vger.kernel.org>,
<davem@davemloft.net>, <yanb@mellanox.com>,
<shlomop@mellanox.com>
Subject: Re: [PATCH net-next V3 3/3] net: Add GRO support for vxlan traffic
Date: Thu, 9 Jan 2014 08:32:24 +0200 [thread overview]
Message-ID: <52CE4278.6050505@mellanox.com> (raw)
In-Reply-To: <1389219101.31367.21.camel@edumazet-glaptop2.roam.corp.google.com>
On 09/01/2014 00:11, Eric Dumazet wrote:
> On Wed, 2014-01-08 at 22:34 +0200, Or Gerlitz wrote:
>
>> +
>> /* Notify netdevs that UDP port started listening */
>> -static void vxlan_notify_add_rx_port(struct sock *sk)
>> +static void vxlan_notify_add_rx_port(struct vxlan_sock *vs)
>> {
>> struct net_device *dev;
>> + struct sock *sk = vs->sock->sk;
>> struct net *net = sock_net(sk);
>> sa_family_t sa_family = sk->sk_family;
>> __be16 port = inet_sk(sk)->inet_sport;
>> @@ -569,12 +671,16 @@ static void vxlan_notify_add_rx_port(struct sock *sk)
>> port);
>> }
>> rcu_read_unlock();
>> +
>> + if (sa_family == AF_INET)
>> + call_rcu(&vs->rcu, vxlan_add_udp_offload);
> Why waiting RCU grace period here?
Basically the add operation can be done right away, however, since the
delete operation can't be done
instantly when we want it, I wanted to protect against a series of
add/del/add in times T1 < T2 < T3
T1 add(X)
T2 del(X)
T3 add(X)
where the delete is deferred and as a result the 2nd add is done before
the delete and @ the end offload X is not added in the 2nd time.From
your other comment below I conclude that I probably miss something about
the rcu usage here, so will give it further thought.
>
>> }
>>
>> /* Notify netdevs that UDP port is no more listening */
>> -static void vxlan_notify_del_rx_port(struct sock *sk)
>> +static void vxlan_notify_del_rx_port(struct vxlan_sock *vs)
>> {
>> struct net_device *dev;
>> + struct sock *sk = vs->sock->sk;
>> struct net *net = sock_net(sk);
>> sa_family_t sa_family = sk->sk_family;
>> __be16 port = inet_sk(sk)->inet_sport;
>> @@ -586,6 +692,9 @@ static void vxlan_notify_del_rx_port(struct sock *sk)
>> port);
>> }
>> rcu_read_unlock();
>> +
>> + if (sa_family == AF_INET)
>> + call_rcu(&vs->rcu, vxlan_del_udp_offload);
>> }
> This looks buggy.
>
> You need to :
>
> 1) remove the offload structure from list
> 2) Then wait rcu grace period, and finally free the memory
>
>
>
prev parent reply other threads:[~2014-01-09 6:32 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-08 20:34 [PATCH net-next V3 0/3] net: Add GRO support for UDP encapsulating protocols Or Gerlitz
2014-01-08 20:34 ` [PATCH net-next V3 1/3] " Or Gerlitz
2014-01-08 20:39 ` Or Gerlitz
2014-01-08 21:58 ` Tom Herbert
2014-01-09 6:25 ` Or Gerlitz
2014-01-09 7:09 ` Tom Herbert
2014-01-09 7:14 ` Or Gerlitz
2014-01-08 20:34 ` [PATCH net-next V3 2/3] net: Export gro_find_by_type helpers Or Gerlitz
2014-01-08 20:34 ` [PATCH net-next V3 3/3] net: Add GRO support for vxlan traffic Or Gerlitz
2014-01-08 22:09 ` Eric Dumazet
2014-01-09 6:28 ` Or Gerlitz
2014-01-08 22:11 ` Eric Dumazet
2014-01-09 6:32 ` Or Gerlitz [this message]
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