[PATCH net-next 04/15] batman-adv: dat: atomically update mac addresses

@@ -376,18 +376,19 @@ batadv_dat_entry_hash_find(struct batadv_priv *bat_priv, __be32 ip,
 static void batadv_dat_entry_add(struct batadv_priv *bat_priv, __be32 ip,
 				 u8 *mac_addr, unsigned short vid)
 {
+	u64 u64_mac = ether_addr_to_u64(mac_addr);
 	struct batadv_dat_entry *dat_entry;
 	int hash_added;
 
 	dat_entry = batadv_dat_entry_hash_find(bat_priv, ip, vid);
 	/* if this entry is already known, just update it */
 	if (dat_entry) {
-		if (!batadv_compare_eth(dat_entry->mac_addr, mac_addr))
-			ether_addr_copy(dat_entry->mac_addr, mac_addr);
+		atomic64_set(&dat_entry->mac_addr, u64_mac);
+
 		dat_entry->last_update = jiffies;
 		batadv_dbg(BATADV_DBG_DAT, bat_priv,
 			   "Entry updated: %pI4 %pM (vid: %d)\n",
-			   &dat_entry->ip, dat_entry->mac_addr,
+			   &dat_entry->ip, mac_addr,
 			   batadv_print_vid(vid));
 		goto out;
 	}

@@ -398,7 +399,7 @@ static void batadv_dat_entry_add(struct batadv_priv *bat_priv, __be32 ip,
 
 	dat_entry->ip = ip;
 	dat_entry->vid = vid;
-	ether_addr_copy(dat_entry->mac_addr, mac_addr);
+	atomic64_set(&dat_entry->mac_addr, u64_mac);
 	dat_entry->last_update = jiffies;
 	kref_init(&dat_entry->refcount);
 

@@ -414,7 +415,7 @@ static void batadv_dat_entry_add(struct batadv_priv *bat_priv, __be32 ip,
 	}
 
 	batadv_dbg(BATADV_DBG_DAT, bat_priv, "New entry added: %pI4 %pM (vid: %d)\n",
-		   &dat_entry->ip, dat_entry->mac_addr, batadv_print_vid(vid));
+		   &dat_entry->ip, mac_addr, batadv_print_vid(vid));
 
 out:
 	batadv_dat_entry_put(dat_entry);

@@ -868,6 +869,8 @@ batadv_dat_cache_dump_entry(struct sk_buff *msg, u32 portid,
 			    struct netlink_callback *cb,
 			    struct batadv_dat_entry *dat_entry)
 {
+	u8 mac[ETH_ALEN];
+	u64 u64_mac;
 	int msecs;
 	void *hdr;
 

@@ -880,11 +883,12 @@ batadv_dat_cache_dump_entry(struct sk_buff *msg, u32 portid,
 	genl_dump_check_consistent(cb, hdr);
 
 	msecs = jiffies_to_msecs(jiffies - dat_entry->last_update);
+	u64_mac = atomic64_read(&dat_entry->mac_addr);
+	u64_to_ether_addr(u64_mac, mac);
 
 	if (nla_put_in_addr(msg, BATADV_ATTR_DAT_CACHE_IP4ADDRESS,
 			    dat_entry->ip) ||
-	    nla_put(msg, BATADV_ATTR_DAT_CACHE_HWADDRESS, ETH_ALEN,
-		    dat_entry->mac_addr) ||
+	    nla_put(msg, BATADV_ATTR_DAT_CACHE_HWADDRESS, ETH_ALEN, mac) ||
 	    nla_put_u16(msg, BATADV_ATTR_DAT_CACHE_VID, dat_entry->vid) ||
 	    nla_put_u32(msg, BATADV_ATTR_LAST_SEEN_MSECS, msecs)) {
 		genlmsg_cancel(msg, hdr);

@@ -1151,6 +1155,8 @@ bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv,
 	struct net_device *mesh_iface = bat_priv->mesh_iface;
 	int hdr_size = 0;
 	unsigned short vid;
+	u8 mac[ETH_ALEN];
+	u64 u64_mac;
 
 	if (!READ_ONCE(bat_priv->distributed_arp_table))
 		goto out;

@@ -1178,6 +1184,9 @@ bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv,
 
 	dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst, vid);
 	if (dat_entry) {
+		u64_mac = atomic64_read(&dat_entry->mac_addr);
+		u64_to_ether_addr(u64_mac, mac);
+
 		/* If the ARP request is destined for a local client the local
 		 * client will answer itself. DAT would only generate a
 		 * duplicate packet.

@@ -1186,7 +1195,7 @@ bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv,
 		 * additional DAT answer may trigger kernel warnings about
 		 * a packet coming from the wrong port.
 		 */
-		if (batadv_is_my_client(bat_priv, dat_entry->mac_addr, vid)) {
+		if (batadv_is_my_client(bat_priv, mac, vid)) {
 			ret = true;
 			goto out;
 		}

@@ -1196,18 +1205,16 @@ bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv,
 		 * the backbone gws belonging to our backbone has claimed the
 		 * destination.
 		 */
-		if (!batadv_bla_check_claim(bat_priv,
-					    dat_entry->mac_addr, vid)) {
+		if (!batadv_bla_check_claim(bat_priv, mac, vid)) {
 			batadv_dbg(BATADV_DBG_DAT, bat_priv,
 				   "Device %pM claimed by another backbone gw. Don't send ARP reply!",
-				   dat_entry->mac_addr);
+				   mac);
 			ret = true;
 			goto out;
 		}
 
 		skb_new = batadv_dat_arp_create_reply(bat_priv, ip_dst, ip_src,
-						      dat_entry->mac_addr,
-						      hw_src, vid);
+						      mac, hw_src, vid);
 		if (!skb_new)
 			goto out;
 

@@ -1249,6 +1256,8 @@ bool batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv,
 	struct batadv_dat_entry *dat_entry = NULL;
 	bool ret = false;
 	unsigned short vid;
+	u8 mac[ETH_ALEN];
+	u64 u64_mac;
 	int err;
 
 	if (!READ_ONCE(bat_priv->distributed_arp_table))

@@ -1276,8 +1285,11 @@ bool batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv,
 	if (!dat_entry)
 		goto out;
 
+	u64_mac = atomic64_read(&dat_entry->mac_addr);
+	u64_to_ether_addr(u64_mac, mac);
+
 	skb_new = batadv_dat_arp_create_reply(bat_priv, ip_dst, ip_src,
-					      dat_entry->mac_addr, hw_src, vid);
+					      mac, hw_src, vid);
 	if (!skb_new)
 		goto out;
 

@@ -1368,6 +1380,8 @@ bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv,
 	u8 *hw_src, *hw_dst;
 	bool dropped = false;
 	unsigned short vid;
+	u8 mac[ETH_ALEN];
+	u64 u64_mac;
 
 	if (!READ_ONCE(bat_priv->distributed_arp_table))
 		goto out;

@@ -1396,11 +1410,17 @@ bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv,
 	 * this frame would lead to doubled receive of an ARP reply.
 	 */
 	dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_src, vid);
-	if (dat_entry && batadv_compare_eth(hw_src, dat_entry->mac_addr)) {
-		batadv_dbg(BATADV_DBG_DAT, bat_priv, "Doubled ARP reply removed: ARP MSG = [src: %pM-%pI4 dst: %pM-%pI4]; dat_entry: %pM-%pI4\n",
-			   hw_src, &ip_src, hw_dst, &ip_dst,
-			   dat_entry->mac_addr,	&dat_entry->ip);
-		dropped = true;
+	if (dat_entry) {
+		u64_mac = atomic64_read(&dat_entry->mac_addr);
+		u64_to_ether_addr(u64_mac, mac);
+
+		if (batadv_compare_eth(hw_src, mac)) {
+			batadv_dbg(BATADV_DBG_DAT, bat_priv,
+				   "Doubled ARP reply removed: ARP MSG = [src: %pM-%pI4 dst: %pM-%pI4]; dat_entry: %pM-%pI4\n",
+				   hw_src, &ip_src, hw_dst, &ip_dst,
+				   mac, &dat_entry->ip);
+			dropped = true;
+		}
 	}
 
 	/* Update our internal cache with both the IP addresses the node got

@@ -2176,7 +2176,7 @@ struct batadv_dat_entry {
 	__be32 ip;
 
 	/** @mac_addr: the MAC address associated to the stored IPv4 */
-	u8 mac_addr[ETH_ALEN];
+	atomic64_t mac_addr;
 
 	/** @vid: the vlan ID associated to this entry */
 	unsigned short vid;