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 <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 998a78f..588a779 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -720,13 +720,13 @@
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) {