Re: [PATCH 1/1] Use RCU for the UDP hash lock

Corey Minyard
2008-09-26T13:37:57Z

Jarek Poplawski wrote:
> On Thu, Sep 25, 2008 at 10:18:33PM -0500, Corey Minyard wrote:
> ...
>
>> This patch is the second try; I believe I fixed all issues that people
>> raised.
>>
>
> Actually, you've skipped my first question, so I still don't know, why
> you don't use an _init version of sk_del_node (even if it's safe in the
> current implementation), while the non-rcu code uses only this?
>
I guess it didn't matter, but it doesn't matter and consistency is
important, so I've changed it.

-corey

> ...
>
>> diff --git a/include/net/sock.h b/include/net/sock.h
>> index 06c5259..65110a6 100644
>> --- a/include/net/sock.h
>> +++ b/include/net/sock.h
>>
> ...
>
>> static inline int sk_unhashed(const struct sock *sk)
>> {
>> return hlist_unhashed(&sk->sk_node);
>> @@ -361,6 +374,27 @@ static __inline__ int sk_del_node_init(struct sock *sk)
>> return rc;
>> }
>>
>> +static inline int __sk_del_node_rcu(struct sock *sk)
>> +{
>> + if (sk_hashed(sk)) {
>> + hlist_del_rcu(&sk->sk_node);
>> + return 1;
>> + }
>> + return 0;
>> +}
>> +
>> +static inline int sk_del_node_rcu(struct sock *sk)
>> +{
>> + int rc = __sk_del_node_rcu(sk);
>> +
>> + if (rc) {
>> + /* paranoid for a while -acme */
>> + WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
>> + __sock_put(sk);
>> + }
>> + return rc;
>> +}
>>
> ...
>
> Jarek P.
>
>