1 files changed, 83 insertions, 54 deletions

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index e51da8c092fa..32d914db6c4f 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -54,62 +54,89 @@ int udp_v6_get_port(struct sock *sk, unsigned short snum)
         return udp_lib_get_port(sk, snum, ipv6_rcv_saddr_equal);
 }
 
+static inline int compute_score(struct sock *sk, struct net *net,
+                                unsigned short hnum,
+                                struct in6_addr *saddr, __be16 sport,
+                                struct in6_addr *daddr, __be16 dport,
+                                int dif)
+{
+        int score = -1;
+
+        if (net_eq(sock_net(sk), net) && sk->sk_hash == hnum &&
+                        sk->sk_family == PF_INET6) {
+                struct ipv6_pinfo *np = inet6_sk(sk);
+                struct inet_sock *inet = inet_sk(sk);
+
+                score = 0;
+                if (inet->dport) {
+                        if (inet->dport != sport)
+                                return -1;
+                        score++;
+                }
+                if (!ipv6_addr_any(&np->rcv_saddr)) {
+                        if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
+                                return -1;
+                        score++;
+                }
+                if (!ipv6_addr_any(&np->daddr)) {
+                        if (!ipv6_addr_equal(&np->daddr, saddr))
+                                return -1;
+                        score++;
+                }
+                if (sk->sk_bound_dev_if) {
+                        if (sk->sk_bound_dev_if != dif)
+                                return -1;
+                        score++;
+                }
+        }
+        return score;
+}
+
 static struct sock *__udp6_lib_lookup(struct net *net,
                                       struct in6_addr *saddr, __be16 sport,
                                       struct in6_addr *daddr, __be16 dport,
-                                      int dif, struct hlist_head udptable[])
+                                      int dif, struct udp_table *udptable)
 {
-        struct sock *sk, *result = NULL;
-        struct hlist_node *node;
+        struct sock *sk, *result;
+        struct hlist_node *node, *next;
         unsigned short hnum = ntohs(dport);
-        int badness = -1;
-
-        read_lock(&udp_hash_lock);
-        sk_for_each(sk, node, &udptable[udp_hashfn(net, hnum)]) {
-                struct inet_sock *inet = inet_sk(sk);
-
-                if (net_eq(sock_net(sk), net) && sk->sk_hash == hnum &&
-                                sk->sk_family == PF_INET6) {
-                        struct ipv6_pinfo *np = inet6_sk(sk);
-                        int score = 0;
-                        if (inet->dport) {
-                                if (inet->dport != sport)
-                                        continue;
-                                score++;
-                        }
-                        if (!ipv6_addr_any(&np->rcv_saddr)) {
-                                if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
-                                        continue;
-                                score++;
-                        }
-                        if (!ipv6_addr_any(&np->daddr)) {
-                                if (!ipv6_addr_equal(&np->daddr, saddr))
-                                        continue;
-                                score++;
-                        }
-                        if (sk->sk_bound_dev_if) {
-                                if (sk->sk_bound_dev_if != dif)
-                                        continue;
-                                score++;
-                        }
-                        if (score == 4) {
-                                result = sk;
-                                break;
-                        } else if (score > badness) {
-                                result = sk;
-                                badness = score;
-                        }
+        unsigned int hash = udp_hashfn(net, hnum);
+        struct udp_hslot *hslot = &udptable->hash[hash];
+        int score, badness;
+
+        rcu_read_lock();
+begin:
+        result = NULL;
+        badness = -1;
+        sk_for_each_rcu_safenext(sk, node, &hslot->head, next) {
+                /*
+                 * 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) {
+                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;
                 }
         }
-        if (result)
-                sock_hold(result);
-        read_unlock(&udp_hash_lock);
+        rcu_read_unlock();
         return result;
 }
 
 static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb,
                                           __be16 sport, __be16 dport,
-                                          struct hlist_head udptable[])
+                                          struct udp_table *udptable)
 {
         struct sock *sk;
         struct ipv6hdr *iph = ipv6_hdr(skb);
@@ -239,7 +266,7 @@ csum_copy_err:
 
 void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
                     int type, int code, int offset, __be32 info,
-                    struct hlist_head udptable[]                    )
+                    struct udp_table *udptable)
 {
         struct ipv6_pinfo *np;
         struct ipv6hdr *hdr = (struct ipv6hdr*)skb->data;
@@ -275,7 +302,7 @@ static __inline__ void udpv6_err(struct sk_buff *skb,
                                  struct inet6_skb_parm *opt, int type,
                                  int code, int offset, __be32 info     )
 {
-        __udp6_lib_err(skb, opt, type, code, offset, info, udp_hash);
+        __udp6_lib_err(skb, opt, type, code, offset, info, &udp_table);
 }
 
 int udpv6_queue_rcv_skb(struct sock * sk, struct sk_buff *skb)
@@ -374,14 +401,15 @@ static struct sock *udp_v6_mcast_next(struct sock *sk,
  */
 static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
                 struct in6_addr *saddr, struct in6_addr *daddr,
-                struct hlist_head udptable[])
+                struct udp_table *udptable)
 {
         struct sock *sk, *sk2;
         const struct udphdr *uh = udp_hdr(skb);
+        struct udp_hslot *hslot = &udptable->hash[udp_hashfn(net, ntohs(uh->dest))];
         int dif;
 
-        read_lock(&udp_hash_lock);
-        sk = sk_head(&udptable[udp_hashfn(net, ntohs(uh->dest))]);
+        spin_lock(&hslot->lock);
+        sk = sk_head(&hslot->head);
         dif = inet6_iif(skb);
         sk = udp_v6_mcast_next(sk, uh->dest, daddr, uh->source, saddr, dif);
         if (!sk) {
@@ -409,7 +437,7 @@ static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
                 sk_add_backlog(sk, skb);
         bh_unlock_sock(sk);
 out:
-        read_unlock(&udp_hash_lock);
+        spin_unlock(&hslot->lock);
         return 0;
 }
 
@@ -447,7 +475,7 @@ static inline int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh,
         return 0;
 }
 
-int __udp6_lib_rcv(struct sk_buff *skb, struct hlist_head udptable[],
+int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
                    int proto)
 {
         struct sock *sk;
@@ -544,7 +572,7 @@ discard:
 
 static __inline__ int udpv6_rcv(struct sk_buff *skb)
 {
-        return __udp6_lib_rcv(skb, udp_hash, IPPROTO_UDP);
+        return __udp6_lib_rcv(skb, &udp_table, IPPROTO_UDP);
 }
 
 /*
@@ -1008,7 +1036,7 @@ int udp6_seq_show(struct seq_file *seq, void *v)
 static struct udp_seq_afinfo udp6_seq_afinfo = {
         .name           = "udp6",
         .family         = AF_INET6,
-        .hashtable      = udp_hash,
+        .udp_table      = &udp_table,
         .seq_fops       = {
                 .owner  =       THIS_MODULE,
         },
@@ -1050,7 +1078,8 @@ struct proto udpv6_prot = {
         .sysctl_wmem       = &sysctl_udp_wmem_min,
         .sysctl_rmem       = &sysctl_udp_rmem_min,
         .obj_size          = sizeof(struct udp6_sock),
-        .h.udp_hash        = udp_hash,
+        .slab_flags        = SLAB_DESTROY_BY_RCU,
+        .h.udp_table       = &udp_table,
 #ifdef CONFIG_COMPAT
         .compat_setsockopt = compat_udpv6_setsockopt,
         .compat_getsockopt = compat_udpv6_getsockopt,