diff options
Diffstat (limited to 'net/ipv4/udp.c')
| -rw-r--r-- | net/ipv4/udp.c | 35 |
1 files changed, 26 insertions, 9 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 2a6c491f97d..0ea974bf796 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -187,7 +187,7 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum, inet_sk(sk)->num = snum; sk->sk_hash = snum; if (sk_unhashed(sk)) { - sk_add_node(sk, &hslot->head); + sk_add_node_rcu(sk, &hslot->head); sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); } error = 0; @@ -253,15 +253,24 @@ static struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport, __be32 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, saddr, hnum, sport, daddr, dport, dif); if (score > badness) { @@ -269,9 +278,16 @@ static struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, 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, saddr, hnum, sport, + daddr, dport, dif) < badness)) { + sock_put(result); + goto begin; + } + } + rcu_read_unlock(); return result; } @@ -953,7 +969,7 @@ void udp_lib_unhash(struct sock *sk) struct udp_hslot *hslot = &udptable->hash[hash]; spin_lock(&hslot->lock); - if (sk_del_node_init(sk)) { + if (sk_del_node_init_rcu(sk)) { inet_sk(sk)->num = 0; sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); } @@ -1517,6 +1533,7 @@ struct proto udp_prot = { .sysctl_wmem = &sysctl_udp_wmem_min, .sysctl_rmem = &sysctl_udp_rmem_min, .obj_size = sizeof(struct udp_sock), + .slab_flags = SLAB_DESTROY_BY_RCU, .h.udp_table = &udp_table, #ifdef CONFIG_COMPAT .compat_setsockopt = compat_udp_setsockopt, |