Re: [B.A.T.M.A.N.] [PATCH 3/6] batman-adv: Distributed ARP Table - create the DHT helper functions

On Sun, Oct 30, 2011 at 09:55:59AM +0100, Antonio Quartulli wrote:

[...]

• for (i = 0; i < hash->size; i++) {
  

• 	head = &hash->table[i];
  

• 	rcu_read_lock();
  

• 	hlist_for_each_entry_rcu(orig_node, node, head,
  

• 				 hash_entry) {
  

• 		if (orig_node->dht_hash > ip_key)
  

• 			tmp_max = USHRT_MAX -
  

• 				orig_node->dht_hash + ip_key;
  

• 		else
  

• 			tmp_max = ip_key - orig_node->dht_hash;
  

• 		/* this is closest! */
  

• 		if (tmp_max <= max)
  

• 			continue;
  

• 		/* this has already been selected */
  

• 		if (tmp_max > last_max)
  

• 			continue;
  

• 		if (!atomic_inc_not_zero(&orig_node->refcount))
  

• 			continue;
  

• 		/* In case of hash collision we can select two
  

• 		 * nodes with the same hash, but we have ensure
  

• 		 * they are different */
  

• 		if (tmp_max == last_max) {
  

• 			for (j = 0; j < select; j++)
  

• 				if (res[j].orig_node ==
  

• 				    orig_node)
  

• 					break;
  

• 			if (j < select)
  

• 				continue;
  

• 		}
  

• 		if (!atomic_inc_not_zero(&orig_node->refcount))
  

• 			continue;
  

Why do you increase the refcount two times? If it is really required, please add a comment.

• 		max = tmp_max;
  

• 		if (max_orig_node)
  

• 			orig_node_free_ref(max_orig_node);
  

• 		max_orig_node = orig_node;
  

• 	}
  

• 	rcu_read_unlock();
  

• }
  

• last_max = max;
  

• if (max_orig_node) {
  

• 	res[select].type = DHT_CANDIDATE_ORIG;
  

• 	res[select].orig_node = max_orig_node;
  

• 	bat_dbg(DBG_ARP, bat_priv, "DHT_SEL_CAND %d: %pM %u\n",
  

• 		select, max_orig_node->orig, max);
  

• }
  

• if (res[select].type == DHT_CANDIDATE_ME) {
  

• 	chosen_me = true;
  

• 	bat_dbg(DBG_ARP, bat_priv, "DHT_SEL_CAND %d: ME %u\n",
  

• 		select, bat_priv->dht_hash);
  

• }
  

• max_orig_node = NULL;
  

• }
• return res;

+}

+/*

• • Sends the skb payload passed as argument to the candidates selected for
• • 'ip'. The skb is copied by means of pskb_copy() and is sent as unicast packet
• • to each of the selected candidate. */

+static bool dht_send_data(struct bat_priv *bat_priv, struct sk_buff *skb,

• 	  uint32_t ip)
  

+{

• int i;
• bool ret = false;
• struct neigh_node *neigh_node = NULL;
• struct sk_buff *tmp_skb;
• struct dht_candidate *cand = dht_select_candidates(bat_priv, ip);
• if (!cand)

• goto out;
  

• bat_dbg(DBG_ARP, bat_priv, "DHT_SEND for %pI4\n", &ip);
• for (i = 0; i < DHT_CANDIDATES_NUM; i++) {

• if (cand[i].type == DHT_CANDIDATE_ME ||
  

•     cand[i].type == DHT_CANDIDATE_NULL) {
  

• 	continue;
  

• }
  

no braces are required here.

• neigh_node = orig_node_get_router(cand[i].orig_node);
  

• if (!neigh_node)
  

• 	goto free_orig;
  

• tmp_skb = pskb_copy(skb, GFP_ATOMIC);
  

• tmp_skb = prepare_unicast_packet(tmp_skb, cand[i].orig_node);
  

• if (tmp_skb)
  

• 	send_skb_packet(tmp_skb, neigh_node->if_incoming,
  

• 			neigh_node->addr);
  

• /* set ret to true only if we send at least one request */
  

• ret = true;
  

• neigh_node_free_ref(neigh_node);
  

+free_orig:

• orig_node_free_ref(cand[i].orig_node);
  

• }

+out:

• kfree(cand);
• return ret;

+}