From c25eb3bfb97294d0543a81230fbc237046b4b84c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 23 Nov 2008 17:22:55 -0800 Subject: net: Convert TCP/DCCP listening hash tables to use RCU This is the last step to be able to perform full RCU lookups in __inet_lookup() : After established/timewait tables, we add RCU lookups to listening hash table. The only trick here is that a socket of a given type (TCP ipv4, TCP ipv6, ...) can now flight between two different tables (established and listening) during a RCU grace period, so we must use different 'nulls' end-of-chain values for two tables. We define a large value : #define LISTENING_NULLS_BASE (1U << 29) So that slots in listening table are guaranteed to have different end-of-chain values than slots in established table. A reader can still detect it finished its lookup in the right chain. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/inet_diag.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/ipv4/inet_diag.c') diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c index 998a78f169ff..588a7796e3e3 100644 --- a/net/ipv4/inet_diag.c +++ b/net/ipv4/inet_diag.c @@ -720,13 +720,13 @@ static int inet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb) for (i = s_i; i < INET_LHTABLE_SIZE; i++) { struct sock *sk; - struct hlist_node *node; + struct hlist_nulls_node *node; struct inet_listen_hashbucket *ilb; num = 0; ilb = &hashinfo->listening_hash[i]; spin_lock_bh(&ilb->lock); - sk_for_each(sk, node, &ilb->head) { + sk_nulls_for_each(sk, node, &ilb->head) { struct inet_sock *inet = inet_sk(sk); if (num < s_num) { -- cgit v1.2.3