[PATCH RFC batadv 02/12] batman-adv: tt: extract allocation of new local entries

The code which allocates and initializes a brand new local TT entry makes
up more than a third of batadv_tt_local_add(). It only shares the addr, vid
and iif_is_wifi parameters with the rest of the function.

Move it to batadv_tt_local_create(), which returns the fully initialized
entry. The error paths become plain returns.

The insertion into bat_priv->tt.local_hash intentionally stays in
batadv_tt_local_add(), keeping the extra reference for the hash next to the
error handling which has to drop it again.

Signed-off-by: Sven Eckelmann <[email protected]>
---
 net/batman-adv/translation-table.c | 135 ++++++++++++++++++++++---------------
 1 file changed, 79 insertions(+), 56 deletions(-)

diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index d040c0d3..8726bbba 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -772,6 +772,84 @@ static bool batadv_tt_iif_is_wifi(struct net *net, int ifindex)
 	return batadv_is_wifi(wifi_flags);
 }
 
+/**
+ * batadv_tt_local_create() - allocate and initialize a local TT entry
+ * @mesh_iface: netdev struct of the mesh interface
+ * @addr: the mac address of the client to add
+ * @vid: VLAN identifier
+ * @iif_is_wifi: whether the client is connected via a wifi interface
+ *
+ * The returned entry is not yet part of bat_priv->tt.local_hash. It is marked
+ * as BATADV_TT_CLIENT_NEW to avoid sending it in a full table response going
+ * out before the next ttvn increment (consistency check).
+ *
+ * Return: the new entry with an initialized reference counter on success, NULL
+ * otherwise.
+ */
+static struct batadv_tt_local_entry *
+batadv_tt_local_create(struct net_device *mesh_iface, const u8 *addr,
+		       unsigned short vid, bool iif_is_wifi)
+{
+	struct batadv_priv *bat_priv = netdev_priv(mesh_iface);
+	struct batadv_tt_local_entry *tt_local;
+	struct batadv_meshif_vlan *vlan;
+	int packet_size_max;
+	int table_size;
+
+	/* Ignore the client if we cannot send it in a full table response. */
+	table_size = batadv_tt_local_table_transmit_size(bat_priv);
+	table_size += batadv_tt_len(1);
+	packet_size_max = READ_ONCE(bat_priv->packet_size_max);
+	if (table_size > packet_size_max) {
+		net_ratelimited_function(batadv_info, mesh_iface,
+					 "Local translation table size (%i) exceeds maximum packet size (%i); Ignoring new local tt entry: %pM\n",
+					 table_size, packet_size_max, addr);
+		return NULL;
+	}
+
+	tt_local = kmem_cache_alloc(batadv_tl_cache, GFP_ATOMIC);
+	if (!tt_local)
+		return NULL;
+
+	/* increase the refcounter of the related vlan */
+	vlan = batadv_meshif_vlan_get(bat_priv, vid);
+	if (!vlan) {
+		net_ratelimited_function(batadv_info, mesh_iface,
+					 "adding TT local entry %pM to non-existent VLAN %d\n",
+					 addr, batadv_print_vid(vid));
+		kmem_cache_free(batadv_tl_cache, tt_local);
+		return NULL;
+	}
+
+	batadv_dbg(BATADV_DBG_TT, bat_priv,
+		   "Creating new local tt entry: %pM (vid: %d, ttvn: %d)\n",
+		   addr, batadv_print_vid(vid),
+		   (u8)atomic_read(&bat_priv->tt.vn));
+
+	ether_addr_copy(tt_local->common.addr, addr);
+	tt_local->common.vid = vid;
+	kref_init(&tt_local->common.refcount);
+	tt_local->last_seen = jiffies;
+	tt_local->common.added_at = tt_local->last_seen;
+	tt_local->vlan = vlan;
+	spin_lock_init(&tt_local->common.flags_lock);
+
+	scoped_guard(spinlock_bh, &tt_local->common.flags_lock) {
+		tt_local->common.flags = BATADV_TT_CLIENT_NEW;
+		if (iif_is_wifi)
+			tt_local->common.flags |= BATADV_TT_CLIENT_WIFI;
+
+		/* the batman interface mac and multicast addresses should never
+		 * be purged
+		 */
+		if (batadv_compare_eth(addr, mesh_iface->dev_addr) ||
+		    is_multicast_ether_addr(addr))
+			tt_local->common.flags |= BATADV_TT_CLIENT_NOPURGE;
+	}
+
+	return tt_local;
+}
+
 /**
  * batadv_tt_local_add() - add a new client to the local table or update an
  *  existing client
@@ -791,14 +869,11 @@ bool batadv_tt_local_add(struct net_device *mesh_iface, const u8 *addr,
 	struct batadv_priv *bat_priv = netdev_priv(mesh_iface);
 	struct batadv_tt_global_entry *tt_global = NULL;
 	struct batadv_tt_local_entry *tt_local;
-	struct batadv_meshif_vlan *vlan;
 	bool roamed_back = false;
-	int packet_size_max;
 	bool iif_is_wifi;
 	bool ret = false;
 	u8 remote_flags;
 	int hash_added;
-	int table_size;
 	u32 match_mark;
 	bool modified;
 
@@ -845,62 +920,10 @@ bool batadv_tt_local_add(struct net_device *mesh_iface, const u8 *addr,
 		goto check_roaming;
 	}
 
-	/* Ignore the client if we cannot send it in a full table response. */
-	table_size = batadv_tt_local_table_transmit_size(bat_priv);
-	table_size += batadv_tt_len(1);
-	packet_size_max = READ_ONCE(bat_priv->packet_size_max);
-	if (table_size > packet_size_max) {
-		net_ratelimited_function(batadv_info, mesh_iface,
-					 "Local translation table size (%i) exceeds maximum packet size (%i); Ignoring new local tt entry: %pM\n",
-					 table_size, packet_size_max, addr);
-		goto out;
-	}
-
-	tt_local = kmem_cache_alloc(batadv_tl_cache, GFP_ATOMIC);
+	tt_local = batadv_tt_local_create(mesh_iface, addr, vid, iif_is_wifi);
 	if (!tt_local)
 		goto out;
 
-	/* increase the refcounter of the related vlan */
-	vlan = batadv_meshif_vlan_get(bat_priv, vid);
-	if (!vlan) {
-		net_ratelimited_function(batadv_info, mesh_iface,
-					 "adding TT local entry %pM to non-existent VLAN %d\n",
-					 addr, batadv_print_vid(vid));
-		kmem_cache_free(batadv_tl_cache, tt_local);
-		tt_local = NULL;
-		goto out;
-	}
-
-	batadv_dbg(BATADV_DBG_TT, bat_priv,
-		   "Creating new local tt entry: %pM (vid: %d, ttvn: %d)\n",
-		   addr, batadv_print_vid(vid),
-		   (u8)atomic_read(&bat_priv->tt.vn));
-
-	ether_addr_copy(tt_local->common.addr, addr);
-	tt_local->common.vid = vid;
-	kref_init(&tt_local->common.refcount);
-	tt_local->last_seen = jiffies;
-	tt_local->common.added_at = tt_local->last_seen;
-	tt_local->vlan = vlan;
-	spin_lock_init(&tt_local->common.flags_lock);
-
-	spin_lock_bh(&tt_local->common.flags_lock);
-	/* The local entry has to be marked as NEW to avoid to send it in
-	 * a full table response going out before the next ttvn increment
-	 * (consistency check)
-	 */
-	tt_local->common.flags = BATADV_TT_CLIENT_NEW;
-	if (iif_is_wifi)
-		tt_local->common.flags |= BATADV_TT_CLIENT_WIFI;
-
-	/* the batman interface mac and multicast addresses should never be
-	 * purged
-	 */
-	if (batadv_compare_eth(addr, mesh_iface->dev_addr) ||
-	    is_multicast_ether_addr(addr))
-		tt_local->common.flags |= BATADV_TT_CLIENT_NOPURGE;
-	spin_unlock_bh(&tt_local->common.flags_lock);
-
 	kref_get(&tt_local->common.refcount);
 	hash_added = batadv_hash_add(bat_priv->tt.local_hash, batadv_compare_tt,
 				     batadv_choose_tt, &tt_local->common,

-- 
2.47.3