Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit d657e621 authored by Antonio Quartulli's avatar Antonio Quartulli
Browse files

batman-adv: add reference counting for type batadv_tt_orig_list_entry 



The batadv_tt_orig_list_entry structure didn't have any refcounting mechanism so
far. This patch introduces it and makes the structure being usable in much more
complex context.

Signed-off-by: default avatarAntonio Quartulli <ordex@autistici.org>
parent 3a7f291b

net/batman-adv/translation-table.c

+52 −23
Original line number Diff line number Diff line
@@ -152,6 +152,8 @@ static void batadv_tt_orig_list_entry_free_rcu(struct rcu_head *rcu) 
static void

batadv_tt_orig_list_entry_free_ref(struct batadv_tt_orig_list_entry *orig_entry)

{

	if (!atomic_dec_and_test(&orig_entry->refcount))

		return;

	/* to avoid race conditions, immediately decrease the tt counter */

	atomic_dec(&orig_entry->orig_node->tt_size);

	call_rcu(&orig_entry->rcu, batadv_tt_orig_list_entry_free_rcu);
@@ -625,50 +627,82 @@ static void batadv_tt_changes_list_free(struct batadv_priv *bat_priv) 
	spin_unlock_bh(&bat_priv->tt_changes_list_lock);

}



/* find out if an orig_node is already in the list of a tt_global_entry.

 * returns 1 if found, 0 otherwise

/* retrieves the orig_tt_list_entry belonging to orig_node from the

 * batadv_tt_global_entry list

 *

 * returns it with an increased refcounter, NULL if not found

 */

static bool

batadv_tt_global_entry_has_orig(const struct batadv_tt_global_entry *entry,

static struct batadv_tt_orig_list_entry *

batadv_tt_global_orig_entry_find(const struct batadv_tt_global_entry *entry,

				 const struct batadv_orig_node *orig_node)

{

	struct batadv_tt_orig_list_entry *tmp_orig_entry;

	struct batadv_tt_orig_list_entry *tmp_orig_entry, *orig_entry = NULL;

	const struct hlist_head *head;

	struct hlist_node *node;

	bool found = false;



	rcu_read_lock();

	head = &entry->orig_list;

	hlist_for_each_entry_rcu(tmp_orig_entry, node, head, list) {

		if (tmp_orig_entry->orig_node == orig_node) {

			found = true;

		if (tmp_orig_entry->orig_node != orig_node)

			continue;

		if (!atomic_inc_not_zero(&tmp_orig_entry->refcount))

			continue;



		orig_entry = tmp_orig_entry;

		break;

	}

	}

	rcu_read_unlock();



	return orig_entry;

}



/* find out if an orig_node is already in the list of a tt_global_entry.

 * returns true if found, false otherwise

 */

static bool

batadv_tt_global_entry_has_orig(const struct batadv_tt_global_entry *entry,

				const struct batadv_orig_node *orig_node)

{

	struct batadv_tt_orig_list_entry *orig_entry;

	bool found = false;



	orig_entry = batadv_tt_global_orig_entry_find(entry, orig_node);

	if (orig_entry) {

		found = true;

		batadv_tt_orig_list_entry_free_ref(orig_entry);

	}



	return found;

}



static void

batadv_tt_global_add_orig_entry(struct batadv_tt_global_entry *tt_global_entry,

batadv_tt_global_orig_entry_add(struct batadv_tt_global_entry *tt_global,

				struct batadv_orig_node *orig_node, int ttvn)

{

	struct batadv_tt_orig_list_entry *orig_entry;



	orig_entry = batadv_tt_global_orig_entry_find(tt_global, orig_node);

	if (orig_entry)

		goto out;



	orig_entry = kzalloc(sizeof(*orig_entry), GFP_ATOMIC);

	if (!orig_entry)

		return;

		goto out;



	INIT_HLIST_NODE(&orig_entry->list);

	atomic_inc(&orig_node->refcount);

	atomic_inc(&orig_node->tt_size);

	orig_entry->orig_node = orig_node;

	orig_entry->ttvn = ttvn;

	atomic_set(&orig_entry->refcount, 2);



	spin_lock_bh(&tt_global_entry->list_lock);

	spin_lock_bh(&tt_global->list_lock);

	hlist_add_head_rcu(&orig_entry->list,

			   &tt_global_entry->orig_list);

	spin_unlock_bh(&tt_global_entry->list_lock);

			   &tt_global->orig_list);

	spin_unlock_bh(&tt_global->list_lock);

out:

	if (orig_entry)

		batadv_tt_orig_list_entry_free_ref(orig_entry);

}



/* caller must hold orig_node refcount */
@@ -709,9 +743,6 @@ int batadv_tt_global_add(struct batadv_priv *bat_priv, 
			batadv_tt_global_entry_free_ref(tt_global_entry);

			goto out_remove;

		}



		batadv_tt_global_add_orig_entry(tt_global_entry, orig_node,

						ttvn);

	} else {

		/* there is already a global entry, use this one. */
@@ -728,11 +759,9 @@ int batadv_tt_global_add(struct batadv_priv *bat_priv, 
			tt_global_entry->roam_at = 0;

		}



		if (!batadv_tt_global_entry_has_orig(tt_global_entry,

						     orig_node))

			batadv_tt_global_add_orig_entry(tt_global_entry,

							orig_node, ttvn);

	}

	/* add the new orig_entry (if needed) */

	batadv_tt_global_orig_entry_add(tt_global_entry, orig_node, ttvn);



	batadv_dbg(BATADV_DBG_TT, bat_priv,

		   "Creating new global tt entry: %pM (via %pM)\n",

net/batman-adv/types.h

+1 −0
Original line number Diff line number Diff line
@@ -282,6 +282,7 @@ struct batadv_tt_global_entry { 
struct batadv_tt_orig_list_entry {

	struct batadv_orig_node *orig_node;

	uint8_t ttvn;

	atomic_t refcount;

	struct rcu_head rcu;

	struct hlist_node list;

};