[NET]: use hlist_unhashed()

Use hlist_unhashed() rather than accessing inside data structure.
Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/list.h

@@ -619,7 +619,7 @@ static inline void hlist_del_rcu(struct hlist_node *n)
 
 static inline void hlist_del_init(struct hlist_node *n)
 {
-	if (n->pprev)  {
+	if (!hlist_unhashed(n)) {
 		__hlist_del(n);
 		INIT_HLIST_NODE(n);
 	}

include/net/inet_timewait_sock.h

@@ -150,7 +150,7 @@ static inline void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
 
 static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
 {
-	return tw->tw_death_node.pprev != NULL;
+	return !hlist_unhashed(&tw->tw_death_node);
 }
 
 static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)

include/net/sock.h

@@ -279,7 +279,7 @@ static inline int sk_unhashed(const struct sock *sk)
 
 static inline int sk_hashed(const struct sock *sk)
 {
-	return sk->sk_node.pprev != NULL;
+	return !sk_unhashed(sk);
 }
 
 static __inline__ void sk_node_init(struct hlist_node *node)