neigh: introduce neigh_confirm() helper function

Add neigh_confirm() for the confirmed member in struct neighbour,
it can be called as an independent unit by other functions.
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/arp.h

@@ -53,13 +53,7 @@ static inline void __ipv4_confirm_neigh(struct net_device *dev, u32 key)
 
 	rcu_read_lock_bh();
 	n = __ipv4_neigh_lookup_noref(dev, key);
-	if (n) {
-		unsigned long now = jiffies;
-
-		/* avoid dirtying neighbour */
-		if (READ_ONCE(n->confirmed) != now)
-			WRITE_ONCE(n->confirmed, now);
-	}
+	neigh_confirm(n);
 	rcu_read_unlock_bh();
 }
 

include/net/ndisc.h

@@ -411,13 +411,7 @@ static inline void __ipv6_confirm_neigh(struct net_device *dev,
 
 	rcu_read_lock_bh();
 	n = __ipv6_neigh_lookup_noref(dev, pkey);
-	if (n) {
-		unsigned long now = jiffies;
-
-		/* avoid dirtying neighbour */
-		if (READ_ONCE(n->confirmed) != now)
-			WRITE_ONCE(n->confirmed, now);
-	}
+	neigh_confirm(n);
 	rcu_read_unlock_bh();
 }
 
@@ -428,13 +422,7 @@ static inline void __ipv6_confirm_neigh_stub(struct net_device *dev,
 
 	rcu_read_lock_bh();
 	n = __ipv6_neigh_lookup_noref_stub(dev, pkey);
-	if (n) {
-		unsigned long now = jiffies;
-
-		/* avoid dirtying neighbour */
-		if (READ_ONCE(n->confirmed) != now)
-			WRITE_ONCE(n->confirmed, now);
-	}
+	neigh_confirm(n);
 	rcu_read_unlock_bh();
 }
 

include/net/neighbour.h

@@ -321,6 +321,17 @@ static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
 	return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
 }
 
+static inline void neigh_confirm(struct neighbour *n)
+{
+	if (n) {
+		unsigned long now = jiffies;
+
+		/* avoid dirtying neighbour */
+		if (READ_ONCE(n->confirmed) != now)
+			WRITE_ONCE(n->confirmed, now);
+	}
+}
+
 void neigh_table_init(int index, struct neigh_table *tbl);
 int neigh_table_clear(int index, struct neigh_table *tbl);
 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,

include/net/sock.h

@@ -2135,13 +2135,10 @@ static inline void sock_confirm_neigh(struct sk_buff *skb, struct neighbour *n)
 {
 	if (skb_get_dst_pending_confirm(skb)) {
 		struct sock *sk = skb->sk;
-		unsigned long now = jiffies;
 
-		/* avoid dirtying neighbour */
-		if (READ_ONCE(n->confirmed) != now)
-			WRITE_ONCE(n->confirmed, now);
 		if (sk && READ_ONCE(sk->sk_dst_pending_confirm))
 			WRITE_ONCE(sk->sk_dst_pending_confirm, 0);
+		neigh_confirm(n);
 	}
 }