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Diffstat (limited to 'net/ipv6/udp.c')
-rw-r--r--net/ipv6/udp.c31
1 files changed, 24 insertions, 7 deletions
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index ccee7244ca0f..1d9790e43dfc 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -97,24 +97,40 @@ static struct sock *__udp6_lib_lookup(struct net *net,
struct in6_addr *daddr, __be16 dport,
int dif, struct udp_table *udptable)
{
- struct sock *sk, *result = NULL;
+ struct sock *sk, *result;
struct hlist_node *node;
unsigned short hnum = ntohs(dport);
unsigned int hash = udp_hashfn(net, hnum);
struct udp_hslot *hslot = &udptable->hash[hash];
- int score, badness = -1;
+ int score, badness;
- spin_lock(&hslot->lock);
- sk_for_each(sk, node, &hslot->head) {
+ rcu_read_lock();
+begin:
+ result = NULL;
+ badness = -1;
+ sk_for_each_rcu(sk, node, &hslot->head) {
+ /*
+ * lockless reader, and SLAB_DESTROY_BY_RCU items:
+ * We must check this item was not moved to another chain
+ */
+ if (udp_hashfn(net, sk->sk_hash) != hash)
+ goto begin;
score = compute_score(sk, net, hnum, saddr, sport, daddr, dport, dif);
if (score > badness) {
result = sk;
badness = score;
}
}
- if (result)
- sock_hold(result);
- spin_unlock(&hslot->lock);
+ if (result) {
+ if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
+ result = NULL;
+ else if (unlikely(compute_score(result, net, hnum, saddr, sport,
+ daddr, dport, dif) < badness)) {
+ sock_put(result);
+ goto begin;
+ }
+ }
+ rcu_read_unlock();
return result;
}
@@ -1062,6 +1078,7 @@ struct proto udpv6_prot = {
.sysctl_wmem = &sysctl_udp_wmem_min,
.sysctl_rmem = &sysctl_udp_rmem_min,
.obj_size = sizeof(struct udp6_sock),
+ .slab_flags = SLAB_DESTROY_BY_RCU,
.h.udp_table = &udp_table,
#ifdef CONFIG_COMPAT
.compat_setsockopt = compat_udpv6_setsockopt,