udp: Use hlist_nulls in UDP RCU code

[pandora-kernel.git] / net / ipv4 / udp.c

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 54badc9..fea2d87 100644 (file)
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -127,9 +127,9 @@ static int udp_lib_lport_inuse(struct net *net, __u16 num,
                                                 const struct sock *sk2))
 {
        struct sock *sk2;
-       struct hlist_node *node;
+       struct hlist_nulls_node *node;
 
-       sk_for_each(sk2, node, &hslot->head)
+       sk_nulls_for_each(sk2, node, &hslot->head)
                if (net_eq(sock_net(sk2), net)                  &&
                    sk2 != sk                                   &&
                    sk2->sk_hash == num                         &&
@@ -189,12 +189,7 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum,
        inet_sk(sk)->num = snum;
        sk->sk_hash = snum;
        if (sk_unhashed(sk)) {
-               /*
-                * We need that previous write to sk->sk_hash committed
-                * before write to sk->next done in following add_node() variant
-                */
-               smp_wmb();
-               sk_add_node_rcu(sk, &hslot->head);
+               sk_nulls_add_node_rcu(sk, &hslot->head);
                sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
        }
        error = 0;
@@ -261,7 +256,7 @@ static struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
                int dif, struct udp_table *udptable)
 {
        struct sock *sk, *result;
-       struct hlist_node *node, *next;
+       struct hlist_nulls_node *node;
        unsigned short hnum = ntohs(dport);
        unsigned int hash = udp_hashfn(net, hnum);
        struct udp_hslot *hslot = &udptable->hash[hash];
@@ -271,13 +266,7 @@ static struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
 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;
+       sk_nulls_for_each_rcu(sk, node, &hslot->head) {
                score = compute_score(sk, net, saddr, hnum, sport,
                                      daddr, dport, dif);
                if (score > badness) {
@@ -285,6 +274,14 @@ begin:
                        badness = score;
                }
        }
+       /*
+        * if the nulls value we got at the end of this lookup is
+        * not the expected one, we must restart lookup.
+        * We probably met an item that was moved to another chain.
+        */
+       if (get_nulls_value(node) != hash)
+               goto begin;
+
        if (result) {
                if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
                        result = NULL;
@@ -325,11 +322,11 @@ static inline struct sock *udp_v4_mcast_next(struct net *net, struct sock *sk,
                                             __be16 rmt_port, __be32 rmt_addr,
                                             int dif)
 {
-       struct hlist_node *node;
+       struct hlist_nulls_node *node;
        struct sock *s = sk;
        unsigned short hnum = ntohs(loc_port);
 
-       sk_for_each_from(s, node) {
+       sk_nulls_for_each_from(s, node) {
                struct inet_sock *inet = inet_sk(s);
 
                if (!net_eq(sock_net(s), net)                           ||
@@ -977,7 +974,7 @@ void udp_lib_unhash(struct sock *sk)
        struct udp_hslot *hslot = &udptable->hash[hash];
 
        spin_lock_bh(&hslot->lock);
-       if (sk_del_node_init_rcu(sk)) {
+       if (sk_nulls_del_node_init_rcu(sk)) {
                inet_sk(sk)->num = 0;
                sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
        }
@@ -1130,7 +1127,7 @@ static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
        int dif;
 
        spin_lock(&hslot->lock);
-       sk = sk_head(&hslot->head);
+       sk = sk_nulls_head(&hslot->head);
        dif = skb->dev->ifindex;
        sk = udp_v4_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
        if (sk) {
@@ -1139,7 +1136,7 @@ static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
                do {
                        struct sk_buff *skb1 = skb;
 
-                       sknext = udp_v4_mcast_next(net, sk_next(sk), uh->dest,
+                       sknext = udp_v4_mcast_next(net, sk_nulls_next(sk), uh->dest,
                                                   daddr, uh->source, saddr,
                                                   dif);
                        if (sknext)
@@ -1560,10 +1557,10 @@ static struct sock *udp_get_first(struct seq_file *seq, int start)
        struct net *net = seq_file_net(seq);
 
        for (state->bucket = start; state->bucket < UDP_HTABLE_SIZE; ++state->bucket) {
-               struct hlist_node *node;
+               struct hlist_nulls_node *node;
                struct udp_hslot *hslot = &state->udp_table->hash[state->bucket];
                spin_lock_bh(&hslot->lock);
-               sk_for_each(sk, node, &hslot->head) {
+               sk_nulls_for_each(sk, node, &hslot->head) {
                        if (!net_eq(sock_net(sk), net))
                                continue;
                        if (sk->sk_family == state->family)
@@ -1582,7 +1579,7 @@ static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
        struct net *net = seq_file_net(seq);
 
        do {
-               sk = sk_next(sk);
+               sk = sk_nulls_next(sk);
        } while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != state->family));
 
        if (!sk) {
@@ -1753,7 +1750,7 @@ void __init udp_table_init(struct udp_table *table)
        int i;
 
        for (i = 0; i < UDP_HTABLE_SIZE; i++) {
-               INIT_HLIST_HEAD(&table->hash[i].head);
+               INIT_HLIST_NULLS_HEAD(&table->hash[i].head, i);
                spin_lock_init(&table->hash[i].lock);
        }
 }