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

From: Corey Minyard
Date: Fri Sep 26 2008 - 09:37:58 EST


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.


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