batman-adv: create a common substructure for tt_global/local_entry

Several functions in the translation table management code assume that the
tt_global_entry and tt_local_entry structures have the same initial fields such
as 'addr' and 'hash_entry'. To improve the code readability and to avoid
mistakes in later changes, a common substructure that substitute the shared
fields has been introduced (struct tt_common_entry).

Thanks to this modification, it has also been possible to slightly reduce the
code length by merging some functions like compare_ltt/gtt() and
tt_local/global_hash_find()
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Sven Eckelmann <sven@narfation.org>

net/batman-adv/types.h

@@ -222,24 +222,24 @@ struct socket_packet {
 	struct icmp_packet_rr icmp_packet;
 };
 
-struct tt_local_entry {
+struct tt_common_entry {
 	uint8_t addr[ETH_ALEN];
 	struct hlist_node hash_entry;
-	unsigned long last_seen;
 	uint16_t flags;
 	atomic_t refcount;
 	struct rcu_head rcu;
 };
 
+struct tt_local_entry {
+	struct tt_common_entry common;
+	unsigned long last_seen;
+};
+
 struct tt_global_entry {
-	uint8_t addr[ETH_ALEN];
-	struct hlist_node hash_entry; /* entry in the global table */
+	struct tt_common_entry common;
 	struct orig_node *orig_node;
 	uint8_t ttvn;
-	uint16_t flags; /* only TT_GLOBAL_ROAM is used */
 	unsigned long roam_at; /* time at which TT_GLOBAL_ROAM was set */
-	atomic_t refcount;
-	struct rcu_head rcu;
 };
 
 struct tt_change_node {

net/batman-adv/vis.c

@@ -609,7 +609,7 @@ static int generate_vis_packet(struct bat_priv *bat_priv)
 	struct vis_info *info = bat_priv->my_vis_info;
 	struct vis_packet *packet = (struct vis_packet *)info->skb_packet->data;
 	struct vis_info_entry *entry;
-	struct tt_local_entry *tt_local_entry;
+	struct tt_common_entry *tt_common_entry;
 	int best_tq = -1;
 	uint32_t i;
 
@@ -672,13 +672,13 @@ static int generate_vis_packet(struct bat_priv *bat_priv)
 		head = &hash->table[i];
 
 		rcu_read_lock();
-		hlist_for_each_entry_rcu(tt_local_entry, node, head,
+		hlist_for_each_entry_rcu(tt_common_entry, node, head,
 					 hash_entry) {
 			entry = (struct vis_info_entry *)
 					skb_put(info->skb_packet,
 						sizeof(*entry));
 			memset(entry->src, 0, ETH_ALEN);
-			memcpy(entry->dest, tt_local_entry->addr, ETH_ALEN);
+			memcpy(entry->dest, tt_common_entry->addr, ETH_ALEN);
 			entry->quality = 0; /* 0 means TT */
 			packet->entries++;