Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into sh-latest

1 files changed, 91 insertions, 51 deletions

diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
index 0065ffb8d96..3cc43558cf9 100644
--- a/net/batman-adv/gateway_client.c
+++ b/net/batman-adv/gateway_client.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009-2010 B.A.T.M.A.N. contributors:
+ * Copyright (C) 2009-2011 B.A.T.M.A.N. contributors:
  *
  * Marek Lindner
  *
@@ -28,58 +28,75 @@
 #include <linux/udp.h>
 #include <linux/if_vlan.h>
 
-static void gw_node_free_ref(struct kref *refcount)
+static void gw_node_free_rcu(struct rcu_head *rcu)
 {
 	struct gw_node *gw_node;
 
-	gw_node = container_of(refcount, struct gw_node, refcount);
+	gw_node = container_of(rcu, struct gw_node, rcu);
 	kfree(gw_node);
 }
 
-static void gw_node_free_rcu(struct rcu_head *rcu)
+static void gw_node_free_ref(struct gw_node *gw_node)
 {
-	struct gw_node *gw_node;
-
-	gw_node = container_of(rcu, struct gw_node, rcu);
-	kref_put(&gw_node->refcount, gw_node_free_ref);
+	if (atomic_dec_and_test(&gw_node->refcount))
+		call_rcu(&gw_node->rcu, gw_node_free_rcu);
 }
 
 void *gw_get_selected(struct bat_priv *bat_priv)
 {
-	struct gw_node *curr_gateway_tmp = bat_priv->curr_gw;
+	struct gw_node *curr_gateway_tmp;
+	struct orig_node *orig_node = NULL;
 
+	rcu_read_lock();
+	curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
 	if (!curr_gateway_tmp)
-		return NULL;
+		goto out;
+
+	orig_node = curr_gateway_tmp->orig_node;
+	if (!orig_node)
+		goto out;
 
-	return curr_gateway_tmp->orig_node;
+	if (!atomic_inc_not_zero(&orig_node->refcount))
+		orig_node = NULL;
+
+out:
+	rcu_read_unlock();
+	return orig_node;
 }
 
 void gw_deselect(struct bat_priv *bat_priv)
 {
-	struct gw_node *gw_node = bat_priv->curr_gw;
+	struct gw_node *gw_node;
 
-	bat_priv->curr_gw = NULL;
+	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);
 
 	if (gw_node)
-		kref_put(&gw_node->refcount, gw_node_free_ref);
+		gw_node_free_ref(gw_node);
 }
 
-static struct gw_node *gw_select(struct bat_priv *bat_priv,
-			  struct gw_node *new_gw_node)
+static void gw_select(struct bat_priv *bat_priv, struct gw_node *new_gw_node)
 {
-	struct gw_node *curr_gw_node = bat_priv->curr_gw;
+	struct gw_node *curr_gw_node;
 
-	if (new_gw_node)
-		kref_get(&new_gw_node->refcount);
+	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);
+	rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);
+	spin_unlock_bh(&bat_priv->gw_list_lock);
 
-	bat_priv->curr_gw = new_gw_node;
-	return curr_gw_node;
+	if (curr_gw_node)
+		gw_node_free_ref(curr_gw_node);
 }
 
 void gw_election(struct bat_priv *bat_priv)
 {
 	struct hlist_node *node;
-	struct gw_node *gw_node, *curr_gw_tmp = NULL, *old_gw_node = NULL;
+	struct gw_node *gw_node, *curr_gw, *curr_gw_tmp = NULL;
 	uint8_t max_tq = 0;
 	uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
 	int down, up;
@@ -93,19 +110,23 @@ void gw_election(struct bat_priv *bat_priv)
 	if (atomic_read(&bat_priv->gw_mode) != GW_MODE_CLIENT)
 		return;
 
-	if (bat_priv->curr_gw)
+	rcu_read_lock();
+	curr_gw = rcu_dereference(bat_priv->curr_gw);
+	if (curr_gw) {
+		rcu_read_unlock();
 		return;
+	}
 
-	rcu_read_lock();
 	if (hlist_empty(&bat_priv->gw_list)) {
-		rcu_read_unlock();
 
-		if (bat_priv->curr_gw) {
+		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;
 	}
@@ -154,12 +175,12 @@ void gw_election(struct bat_priv *bat_priv)
 			max_gw_factor = tmp_gw_factor;
 	}
 
-	if (bat_priv->curr_gw != curr_gw_tmp) {
-		if ((bat_priv->curr_gw) && (!curr_gw_tmp))
+	if (curr_gw != curr_gw_tmp) {
+		if ((curr_gw) && (!curr_gw_tmp))
 			bat_dbg(DBG_BATMAN, bat_priv,
 				"Removing selected gateway - "
 				"no gateway in range\n");
-		else if ((!bat_priv->curr_gw) && (curr_gw_tmp))
+		else if ((!curr_gw) && (curr_gw_tmp))
 			bat_dbg(DBG_BATMAN, bat_priv,
 				"Adding route to gateway %pM "
 				"(gw_flags: %i, tq: %i)\n",
@@ -174,43 +195,43 @@ void gw_election(struct bat_priv *bat_priv)
 				curr_gw_tmp->orig_node->gw_flags,
 				curr_gw_tmp->orig_node->router->tq_avg);
 
-		old_gw_node = gw_select(bat_priv, curr_gw_tmp);
+		gw_select(bat_priv, curr_gw_tmp);
 	}
 
 	rcu_read_unlock();
-
-	/* the kfree() has to be outside of the rcu lock */
-	if (old_gw_node)
-		kref_put(&old_gw_node->refcount, gw_node_free_ref);
 }
 
 void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
 {
-	struct gw_node *curr_gateway_tmp = bat_priv->curr_gw;
+	struct gw_node *curr_gateway_tmp;
 	uint8_t gw_tq_avg, orig_tq_avg;
 
+	rcu_read_lock();
+	curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
 	if (!curr_gateway_tmp)
-		return;
+		goto out_rcu;
 
 	if (!curr_gateway_tmp->orig_node)
-		goto deselect;
+		goto deselect_rcu;
 
 	if (!curr_gateway_tmp->orig_node->router)
-		goto deselect;
+		goto deselect_rcu;
 
 	/* this node already is the gateway */
 	if (curr_gateway_tmp->orig_node == orig_node)
-		return;
+		goto out_rcu;
 
 	if (!orig_node->router)
-		return;
+		goto out_rcu;
 
 	gw_tq_avg = curr_gateway_tmp->orig_node->router->tq_avg;
+	rcu_read_unlock();
+
 	orig_tq_avg = orig_node->router->tq_avg;
 
 	/* the TQ value has to be better */
 	if (orig_tq_avg < gw_tq_avg)
-		return;
+		goto out;
 
 	/**
 	 * if the routing class is greater than 3 the value tells us how much
@@ -218,15 +239,23 @@ void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
 	 **/
 	if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
 	    (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
-		return;
+		goto out;
 
 	bat_dbg(DBG_BATMAN, bat_priv,
 		"Restarting gateway selection: better gateway found (tq curr: "
 		"%i, tq new: %i)\n",
 		gw_tq_avg, orig_tq_avg);
+	goto deselect;
 
+out_rcu:
+	rcu_read_unlock();
+	goto out;
+deselect_rcu:
+	rcu_read_unlock();
 deselect:
 	gw_deselect(bat_priv);
+out:
+	return;
 }
 
 static void gw_node_add(struct bat_priv *bat_priv,
@@ -242,7 +271,7 @@ static void gw_node_add(struct bat_priv *bat_priv,
 	memset(gw_node, 0, sizeof(struct gw_node));
 	INIT_HLIST_NODE(&gw_node->list);
 	gw_node->orig_node = orig_node;
-	kref_init(&gw_node->refcount);
+	atomic_set(&gw_node->refcount, 1);
 
 	spin_lock_bh(&bat_priv->gw_list_lock);
 	hlist_add_head_rcu(&gw_node->list, &bat_priv->gw_list);
@@ -283,7 +312,7 @@ void gw_node_update(struct bat_priv *bat_priv,
 				"Gateway %pM removed from gateway list\n",
 				orig_node->orig);
 
-			if (gw_node == bat_priv->curr_gw) {
+			if (gw_node == rcu_dereference(bat_priv->curr_gw)) {
 				rcu_read_unlock();
 				gw_deselect(bat_priv);
 				return;
@@ -321,11 +350,11 @@ void gw_node_purge(struct bat_priv *bat_priv)
 		    atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE)
 			continue;
 
-		if (bat_priv->curr_gw == gw_node)
+		if (rcu_dereference(bat_priv->curr_gw) == gw_node)
 			gw_deselect(bat_priv);
 
 		hlist_del_rcu(&gw_node->list);
-		call_rcu(&gw_node->rcu, gw_node_free_rcu);
+		gw_node_free_ref(gw_node);
 	}
 
 
@@ -335,12 +364,16 @@ void gw_node_purge(struct bat_priv *bat_priv)
 static int _write_buffer_text(struct bat_priv *bat_priv,
 			      struct seq_file *seq, struct gw_node *gw_node)
 {
-	int down, up;
+	struct gw_node *curr_gw;
+	int down, up, ret;
 
 	gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);
 
-	return seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
-		       (bat_priv->curr_gw == gw_node ? "=>" : "  "),
+	rcu_read_lock();
+	curr_gw = rcu_dereference(bat_priv->curr_gw);
+
+	ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
+		       (curr_gw == gw_node ? "=>" : "  "),
 		       gw_node->orig_node->orig,
 		       gw_node->orig_node->router->tq_avg,
 		       gw_node->orig_node->router->addr,
@@ -350,6 +383,9 @@ static int _write_buffer_text(struct bat_priv *bat_priv,
 		       (down > 2048 ? "MBit" : "KBit"),
 		       (up > 2048 ? up / 1024 : up),
 		       (up > 2048 ? "MBit" : "KBit"));
+
+	rcu_read_unlock();
+	return ret;
 }
 
 int gw_client_seq_print_text(struct seq_file *seq, void *offset)
@@ -470,8 +506,12 @@ int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb)
 	if (atomic_read(&bat_priv->gw_mode) == GW_MODE_SERVER)
 		return -1;
 
-	if (!bat_priv->curr_gw)
+	rcu_read_lock();
+	if (!rcu_dereference(bat_priv->curr_gw)) {
+		rcu_read_unlock();
 		return 0;
+	}
+	rcu_read_unlock();
 
 	return 1;
 }