diff options
Diffstat (limited to 'net/ipv6/udp.c')
| -rw-r--r-- | net/ipv6/udp.c | 31 |
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, |