batman-adv: concentrate all curr_gw related rcu operations in select/deselect functions
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
index 42a8a7b..2acd7a66 100644
--- a/net/batman-adv/gateway_client.c
+++ b/net/batman-adv/gateway_client.c
@@ -43,61 +43,75 @@
call_rcu(&gw_node->rcu, gw_node_free_rcu);
}
-struct orig_node *gw_get_selected(struct bat_priv *bat_priv)
+static struct gw_node *gw_get_selected_gw_node(struct bat_priv *bat_priv)
{
- struct gw_node *curr_gateway_tmp;
- struct orig_node *orig_node = NULL;
+ struct gw_node *gw_node;
rcu_read_lock();
- curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
- if (!curr_gateway_tmp)
+ gw_node = rcu_dereference(bat_priv->curr_gw);
+ if (!gw_node)
goto out;
- orig_node = curr_gateway_tmp->orig_node;
- if (!orig_node)
+ if (!atomic_inc_not_zero(&gw_node->refcount))
+ gw_node = NULL;
+
+out:
+ rcu_read_unlock();
+ return gw_node;
+}
+
+struct orig_node *gw_get_selected_orig(struct bat_priv *bat_priv)
+{
+ struct gw_node *gw_node;
+ struct orig_node *orig_node = NULL;
+
+ gw_node = gw_get_selected_gw_node(bat_priv);
+ if (!gw_node)
goto out;
+ rcu_read_lock();
+ orig_node = gw_node->orig_node;
+ if (!orig_node)
+ goto unlock;
+
if (!atomic_inc_not_zero(&orig_node->refcount))
orig_node = NULL;
-out:
+unlock:
rcu_read_unlock();
- return orig_node;
-}
-
-void gw_deselect(struct bat_priv *bat_priv)
-{
- struct gw_node *gw_node;
-
- spin_lock_bh(&bat_priv->gw_list_lock);
- gw_node = rcu_dereference(bat_priv->curr_gw);
- rcu_assign_pointer(bat_priv->curr_gw, NULL);
- spin_unlock_bh(&bat_priv->gw_list_lock);
-
+out:
if (gw_node)
gw_node_free_ref(gw_node);
+ return orig_node;
}
static void gw_select(struct bat_priv *bat_priv, struct gw_node *new_gw_node)
{
struct gw_node *curr_gw_node;
+ spin_lock_bh(&bat_priv->gw_list_lock);
+
if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
new_gw_node = NULL;
- spin_lock_bh(&bat_priv->gw_list_lock);
- curr_gw_node = rcu_dereference(bat_priv->curr_gw);
+ curr_gw_node = bat_priv->curr_gw;
rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);
- spin_unlock_bh(&bat_priv->gw_list_lock);
if (curr_gw_node)
gw_node_free_ref(curr_gw_node);
+
+ spin_unlock_bh(&bat_priv->gw_list_lock);
+}
+
+void gw_deselect(struct bat_priv *bat_priv)
+{
+ gw_select(bat_priv, NULL);
}
void gw_election(struct bat_priv *bat_priv)
{
struct hlist_node *node;
- struct gw_node *gw_node, *curr_gw, *curr_gw_tmp = NULL;
+ struct gw_node *gw_node, *curr_gw = NULL, *curr_gw_tmp = NULL;
struct neigh_node *router;
uint8_t max_tq = 0;
uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
@@ -112,25 +126,17 @@
if (atomic_read(&bat_priv->gw_mode) != GW_MODE_CLIENT)
return;
+ curr_gw = gw_get_selected_gw_node(bat_priv);
+ if (!curr_gw)
+ goto out;
+
rcu_read_lock();
- curr_gw = rcu_dereference(bat_priv->curr_gw);
- if (curr_gw) {
- rcu_read_unlock();
- return;
- }
-
if (hlist_empty(&bat_priv->gw_list)) {
-
- if (curr_gw) {
- rcu_read_unlock();
- bat_dbg(DBG_BATMAN, bat_priv,
- "Removing selected gateway - "
- "no gateway in range\n");
- gw_deselect(bat_priv);
- } else
- rcu_read_unlock();
-
- return;
+ bat_dbg(DBG_BATMAN, bat_priv,
+ "Removing selected gateway - "
+ "no gateway in range\n");
+ gw_deselect(bat_priv);
+ goto unlock;
}
hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
@@ -182,7 +188,7 @@
if (curr_gw != curr_gw_tmp) {
router = orig_node_get_router(curr_gw_tmp->orig_node);
if (!router)
- goto out;
+ goto unlock;
if ((curr_gw) && (!curr_gw_tmp))
bat_dbg(DBG_BATMAN, bat_priv,
@@ -207,8 +213,11 @@
gw_select(bat_priv, curr_gw_tmp);
}
-out:
+unlock:
rcu_read_unlock();
+out:
+ if (curr_gw)
+ gw_node_free_ref(curr_gw);
}
void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
@@ -217,7 +226,7 @@
struct neigh_node *router_gw = NULL, *router_orig = NULL;
uint8_t gw_tq_avg, orig_tq_avg;
- curr_gw_orig = gw_get_selected(bat_priv);
+ curr_gw_orig = gw_get_selected_orig(bat_priv);
if (!curr_gw_orig)
goto deselect;
@@ -299,7 +308,11 @@
struct orig_node *orig_node, uint8_t new_gwflags)
{
struct hlist_node *node;
- struct gw_node *gw_node;
+ struct gw_node *gw_node, *curr_gw;
+
+ curr_gw = gw_get_selected_gw_node(bat_priv);
+ if (!curr_gw)
+ goto out;
rcu_read_lock();
hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
@@ -320,22 +333,26 @@
"Gateway %pM removed from gateway list\n",
orig_node->orig);
- if (gw_node == rcu_dereference(bat_priv->curr_gw)) {
- rcu_read_unlock();
- gw_deselect(bat_priv);
- return;
- }
+ if (gw_node == curr_gw)
+ goto deselect;
}
- rcu_read_unlock();
- return;
+ goto unlock;
}
- rcu_read_unlock();
if (new_gwflags == 0)
- return;
+ goto unlock;
gw_node_add(bat_priv, orig_node, new_gwflags);
+ goto unlock;
+
+deselect:
+ gw_deselect(bat_priv);
+unlock:
+ rcu_read_unlock();
+out:
+ if (curr_gw)
+ gw_node_free_ref(curr_gw);
}
void gw_node_delete(struct bat_priv *bat_priv, struct orig_node *orig_node)
@@ -345,9 +362,12 @@
void gw_node_purge(struct bat_priv *bat_priv)
{
- struct gw_node *gw_node;
+ struct gw_node *gw_node, *curr_gw;
struct hlist_node *node, *node_tmp;
unsigned long timeout = 2 * PURGE_TIMEOUT * HZ;
+ char do_deselect = 0;
+
+ curr_gw = gw_get_selected_gw_node(bat_priv);
spin_lock_bh(&bat_priv->gw_list_lock);
@@ -358,15 +378,21 @@
atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE)
continue;
- if (rcu_dereference(bat_priv->curr_gw) == gw_node)
- gw_deselect(bat_priv);
+ if (curr_gw == gw_node)
+ do_deselect = 1;
hlist_del_rcu(&gw_node->list);
gw_node_free_ref(gw_node);
}
-
spin_unlock_bh(&bat_priv->gw_list_lock);
+
+ /* gw_deselect() needs to acquire the gw_list_lock */
+ if (do_deselect)
+ gw_deselect(bat_priv);
+
+ if (curr_gw)
+ gw_node_free_ref(curr_gw);
}
/**
@@ -385,22 +411,22 @@
if (!router)
goto out;
- rcu_read_lock();
- curr_gw = rcu_dereference(bat_priv->curr_gw);
+ curr_gw = gw_get_selected_gw_node(bat_priv);
ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
- (curr_gw == gw_node ? "=>" : " "),
- gw_node->orig_node->orig,
- router->tq_avg, router->addr,
- router->if_incoming->net_dev->name,
- gw_node->orig_node->gw_flags,
- (down > 2048 ? down / 1024 : down),
- (down > 2048 ? "MBit" : "KBit"),
- (up > 2048 ? up / 1024 : up),
- (up > 2048 ? "MBit" : "KBit"));
+ (curr_gw == gw_node ? "=>" : " "),
+ gw_node->orig_node->orig,
+ router->tq_avg, router->addr,
+ router->if_incoming->net_dev->name,
+ gw_node->orig_node->gw_flags,
+ (down > 2048 ? down / 1024 : down),
+ (down > 2048 ? "MBit" : "KBit"),
+ (up > 2048 ? up / 1024 : up),
+ (up > 2048 ? "MBit" : "KBit"));
- rcu_read_unlock();
neigh_node_free_ref(router);
+ if (curr_gw)
+ gw_node_free_ref(curr_gw);
out:
return ret;
}
@@ -459,6 +485,7 @@
struct iphdr *iphdr;
struct ipv6hdr *ipv6hdr;
struct udphdr *udphdr;
+ struct gw_node *curr_gw;
unsigned int header_len = 0;
if (atomic_read(&bat_priv->gw_mode) == GW_MODE_OFF)
@@ -523,12 +550,11 @@
if (atomic_read(&bat_priv->gw_mode) == GW_MODE_SERVER)
return -1;
- rcu_read_lock();
- if (!rcu_dereference(bat_priv->curr_gw)) {
- rcu_read_unlock();
+ curr_gw = gw_get_selected_gw_node(bat_priv);
+ if (!curr_gw)
return 0;
- }
- rcu_read_unlock();
+ if (curr_gw)
+ gw_node_free_ref(curr_gw);
return 1;
}
diff --git a/net/batman-adv/gateway_client.h b/net/batman-adv/gateway_client.h
index 97c31d1..1ce8c60 100644
--- a/net/batman-adv/gateway_client.h
+++ b/net/batman-adv/gateway_client.h
@@ -24,7 +24,7 @@
void gw_deselect(struct bat_priv *bat_priv);
void gw_election(struct bat_priv *bat_priv);
-struct orig_node *gw_get_selected(struct bat_priv *bat_priv);
+struct orig_node *gw_get_selected_orig(struct bat_priv *bat_priv);
void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node);
void gw_node_update(struct bat_priv *bat_priv,
struct orig_node *orig_node, uint8_t new_gwflags);
diff --git a/net/batman-adv/unicast.c b/net/batman-adv/unicast.c
index 19f84bd..d46acc8 100644
--- a/net/batman-adv/unicast.c
+++ b/net/batman-adv/unicast.c
@@ -289,7 +289,7 @@
/* get routing information */
if (is_multicast_ether_addr(ethhdr->h_dest)) {
- orig_node = (struct orig_node *)gw_get_selected(bat_priv);
+ orig_node = (struct orig_node *)gw_get_selected_orig(bat_priv);
if (orig_node)
goto find_router;
}