@@ -542,6 +542,41 @@ static inline void hlist_add_behind_rcu(struct hlist_node *n,
n->next->pprev = &n->next;
}
+/**
+ * hlist_add_tail_rcu
+ * @n: the element to add to the hash list.
+ * @h: the list to add to.
+ *
+ * Description:
+ * Adds the specified element to the end of the specified hlist_nulls,
+ * while permitting racing traversals. NOTE: tail insertion requires
+ * list traversal.
+ *
+ * The caller must take whatever precautions are necessary
+ * (such as holding appropriate locks) to avoid racing
+ * with another list-mutation primitive, such as hlist_add_head_rcu()
+ * or hlist_del_rcu(), running on this same list.
+ * However, it is perfectly legal to run concurrently with
+ * the _rcu list-traversal primitives, such as
+ * hlist_for_each_entry_rcu(), used to prevent memory-consistency
+ * problems on Alpha CPUs. Regardless of the type of CPU, the
+ * list-traversal primitive must be guarded by rcu_read_lock().
+ */
+
+static inline void hlist_add_tail_rcu(struct hlist_node *n,
+ struct hlist_head *h)
+{
+ struct hlist_node *i, *last = NULL;
+
+ for (i = hlist_first_rcu(h); i; i = hlist_next_rcu(i))
+ last = i;
+
+ if (last)
+ hlist_add_behind_rcu(n, last);
+ else
+ hlist_add_head_rcu(n, h);
+}
+
#define __hlist_for_each_rcu(pos, head) \
for (pos = rcu_dereference(hlist_first_rcu(head)); \
pos; \
@@ -630,7 +630,11 @@ static inline void sk_add_node(struct sock *sk, struct hlist_head *list)
static inline void sk_add_node_rcu(struct sock *sk, struct hlist_head *list)
{
sock_hold(sk);
- hlist_add_head_rcu(&sk->sk_node, list);
+ if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
+ sk->sk_family == AF_INET6)
+ hlist_add_tail_rcu(&sk->sk_node, list);
+ else
+ hlist_add_head_rcu(&sk->sk_node, list);
}
static inline void __sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
@@ -479,7 +479,11 @@ int __inet_hash(struct sock *sk, struct sock *osk,
if (err)
goto unlock;
}
- hlist_add_head_rcu(&sk->sk_node, &ilb->head);
+ if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
+ sk->sk_family == AF_INET6)
+ hlist_add_tail_rcu(&sk->sk_node, &ilb->head);
+ else
+ hlist_add_head_rcu(&sk->sk_node, &ilb->head);
sock_set_flag(sk, SOCK_RCU_FREE);
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
unlock:
@@ -336,8 +336,13 @@ found:
hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
spin_lock(&hslot2->lock);
- hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
- &hslot2->head);
+ if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
+ sk->sk_family == AF_INET6)
+ hlist_add_tail_rcu(&udp_sk(sk)->udp_portaddr_node,
+ &hslot2->head);
+ else
+ hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
+ &hslot2->head);
hslot2->count++;
spin_unlock(&hslot2->lock);
}