batman-adv: Make bat_priv->curr_gw an rcu protected pointer
The rcu protected macros rcu_dereference() and rcu_assign_pointer() for the bat_priv->curr_gw need to be used, as well as spin/rcu locking. Otherwise we might end up using a curr_gw pointer pointing to already freed memory. Reported-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Linus Lüssing <linus.luessing@ascom.ch> Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
This commit is contained in:
Linus Lüssing
Marek Lindner
parent
f3e0008f01
commit
5d02b3cdfa
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@ -44,19 +44,29 @@ static void gw_node_free_ref(struct gw_node *gw_node)
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void *gw_get_selected(struct bat_priv *bat_priv)
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{
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struct gw_node *curr_gateway_tmp = bat_priv->curr_gw;
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struct gw_node *curr_gateway_tmp;
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struct orig_node *orig_node = NULL;
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rcu_read_lock();
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curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
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if (!curr_gateway_tmp)
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return NULL;
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goto out;
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return curr_gateway_tmp->orig_node;
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orig_node = curr_gateway_tmp->orig_node;
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out:
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rcu_read_unlock();
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return orig_node;
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}
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void gw_deselect(struct bat_priv *bat_priv)
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{
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struct gw_node *gw_node = bat_priv->curr_gw;
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struct gw_node *gw_node;
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bat_priv->curr_gw = NULL;
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spin_lock_bh(&bat_priv->gw_list_lock);
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gw_node = rcu_dereference(bat_priv->curr_gw);
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rcu_assign_pointer(bat_priv->curr_gw, NULL);
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spin_unlock_bh(&bat_priv->gw_list_lock);
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if (gw_node)
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gw_node_free_ref(gw_node);
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@ -64,12 +74,15 @@ void gw_deselect(struct bat_priv *bat_priv)
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static void gw_select(struct bat_priv *bat_priv, struct gw_node *new_gw_node)
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{
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struct gw_node *curr_gw_node = bat_priv->curr_gw;
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struct gw_node *curr_gw_node;
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if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
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new_gw_node = NULL;
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bat_priv->curr_gw = new_gw_node;
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spin_lock_bh(&bat_priv->gw_list_lock);
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curr_gw_node = rcu_dereference(bat_priv->curr_gw);
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rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);
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spin_unlock_bh(&bat_priv->gw_list_lock);
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if (curr_gw_node)
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gw_node_free_ref(curr_gw_node);
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@ -78,7 +91,7 @@ static void gw_select(struct bat_priv *bat_priv, struct gw_node *new_gw_node)
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void gw_election(struct bat_priv *bat_priv)
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{
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struct hlist_node *node;
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struct gw_node *gw_node, *curr_gw_tmp = NULL;
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struct gw_node *gw_node, *curr_gw, *curr_gw_tmp = NULL;
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uint8_t max_tq = 0;
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uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
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int down, up;
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@ -92,19 +105,23 @@ void gw_election(struct bat_priv *bat_priv)
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if (atomic_read(&bat_priv->gw_mode) != GW_MODE_CLIENT)
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return;
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if (bat_priv->curr_gw)
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return;
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rcu_read_lock();
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if (hlist_empty(&bat_priv->gw_list)) {
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curr_gw = rcu_dereference(bat_priv->curr_gw);
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if (curr_gw) {
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rcu_read_unlock();
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return;
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}
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if (bat_priv->curr_gw) {
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if (hlist_empty(&bat_priv->gw_list)) {
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if (curr_gw) {
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rcu_read_unlock();
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bat_dbg(DBG_BATMAN, bat_priv,
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"Removing selected gateway - "
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"no gateway in range\n");
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gw_deselect(bat_priv);
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}
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} else
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rcu_read_unlock();
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return;
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}
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@ -153,12 +170,12 @@ void gw_election(struct bat_priv *bat_priv)
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max_gw_factor = tmp_gw_factor;
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}
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if (bat_priv->curr_gw != curr_gw_tmp) {
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if ((bat_priv->curr_gw) && (!curr_gw_tmp))
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if (curr_gw != curr_gw_tmp) {
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if ((curr_gw) && (!curr_gw_tmp))
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bat_dbg(DBG_BATMAN, bat_priv,
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"Removing selected gateway - "
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"no gateway in range\n");
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else if ((!bat_priv->curr_gw) && (curr_gw_tmp))
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else if ((!curr_gw) && (curr_gw_tmp))
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bat_dbg(DBG_BATMAN, bat_priv,
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"Adding route to gateway %pM "
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"(gw_flags: %i, tq: %i)\n",
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@ -181,31 +198,35 @@ void gw_election(struct bat_priv *bat_priv)
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void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
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{
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struct gw_node *curr_gateway_tmp = bat_priv->curr_gw;
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struct gw_node *curr_gateway_tmp;
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uint8_t gw_tq_avg, orig_tq_avg;
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rcu_read_lock();
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curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
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if (!curr_gateway_tmp)
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return;
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goto out_rcu;
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if (!curr_gateway_tmp->orig_node)
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goto deselect;
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goto deselect_rcu;
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if (!curr_gateway_tmp->orig_node->router)
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goto deselect;
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goto deselect_rcu;
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/* this node already is the gateway */
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if (curr_gateway_tmp->orig_node == orig_node)
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return;
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goto out_rcu;
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if (!orig_node->router)
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return;
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goto out_rcu;
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gw_tq_avg = curr_gateway_tmp->orig_node->router->tq_avg;
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rcu_read_unlock();
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orig_tq_avg = orig_node->router->tq_avg;
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/* the TQ value has to be better */
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if (orig_tq_avg < gw_tq_avg)
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return;
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goto out;
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/**
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* if the routing class is greater than 3 the value tells us how much
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@ -213,15 +234,23 @@ void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
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**/
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if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
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(orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
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return;
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goto out;
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bat_dbg(DBG_BATMAN, bat_priv,
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"Restarting gateway selection: better gateway found (tq curr: "
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"%i, tq new: %i)\n",
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gw_tq_avg, orig_tq_avg);
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goto deselect;
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out_rcu:
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rcu_read_unlock();
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goto out;
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deselect_rcu:
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rcu_read_unlock();
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deselect:
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gw_deselect(bat_priv);
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out:
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return;
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}
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static void gw_node_add(struct bat_priv *bat_priv,
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@ -278,7 +307,7 @@ void gw_node_update(struct bat_priv *bat_priv,
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"Gateway %pM removed from gateway list\n",
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orig_node->orig);
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if (gw_node == bat_priv->curr_gw) {
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if (gw_node == rcu_dereference(bat_priv->curr_gw)) {
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rcu_read_unlock();
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gw_deselect(bat_priv);
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return;
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@ -316,7 +345,7 @@ void gw_node_purge(struct bat_priv *bat_priv)
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atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE)
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continue;
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if (bat_priv->curr_gw == gw_node)
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if (rcu_dereference(bat_priv->curr_gw) == gw_node)
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gw_deselect(bat_priv);
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hlist_del_rcu(&gw_node->list);
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@ -330,12 +359,16 @@ void gw_node_purge(struct bat_priv *bat_priv)
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static int _write_buffer_text(struct bat_priv *bat_priv,
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struct seq_file *seq, struct gw_node *gw_node)
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{
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int down, up;
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struct gw_node *curr_gw;
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int down, up, ret;
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gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);
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return seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
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(bat_priv->curr_gw == gw_node ? "=>" : " "),
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rcu_read_lock();
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curr_gw = rcu_dereference(bat_priv->curr_gw);
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ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
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(curr_gw == gw_node ? "=>" : " "),
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gw_node->orig_node->orig,
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gw_node->orig_node->router->tq_avg,
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gw_node->orig_node->router->addr,
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@ -345,6 +378,9 @@ static int _write_buffer_text(struct bat_priv *bat_priv,
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(down > 2048 ? "MBit" : "KBit"),
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(up > 2048 ? up / 1024 : up),
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(up > 2048 ? "MBit" : "KBit"));
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rcu_read_unlock();
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return ret;
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}
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int gw_client_seq_print_text(struct seq_file *seq, void *offset)
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@ -465,8 +501,12 @@ int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb)
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if (atomic_read(&bat_priv->gw_mode) == GW_MODE_SERVER)
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return -1;
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if (!bat_priv->curr_gw)
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rcu_read_lock();
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if (!rcu_dereference(bat_priv->curr_gw)) {
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rcu_read_unlock();
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return 0;
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}
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rcu_read_unlock();
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return 1;
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}
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@ -162,7 +162,7 @@ struct bat_priv {
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spinlock_t forw_bcast_list_lock; /* protects */
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spinlock_t hna_lhash_lock; /* protects hna_local_hash */
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spinlock_t hna_ghash_lock; /* protects hna_global_hash */
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spinlock_t gw_list_lock; /* protects gw_list */
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spinlock_t gw_list_lock; /* protects gw_list and curr_gw */
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spinlock_t vis_hash_lock; /* protects vis_hash */
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spinlock_t vis_list_lock; /* protects vis_info::recv_list */
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spinlock_t softif_neigh_lock; /* protects soft-interface neigh list */
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@ -171,7 +171,7 @@ struct bat_priv {
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struct delayed_work hna_work;
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struct delayed_work orig_work;
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struct delayed_work vis_work;
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struct gw_node *curr_gw;
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struct gw_node __rcu *curr_gw; /* rcu protected pointer */
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struct vis_info *my_vis_info;
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};
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