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batman-adv: Fix consistency of update route messages

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The debug messages of _batadv_update_route were printed before the actual
route change is done. At this point it is not really known which
curr_router will be replaced. Thus the messages could print the wrong
operation.

Printing the debug messages after the operation was done avoids this
problem.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
This commit is contained in:
Sven Eckelmann 2016-06-29 23:45:57 +02:00 committed by Simon Wunderlich
parent 4d7de48c79
commit b5dcbad252
1 changed files with 17 additions and 26 deletions
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43
net/batman-adv/routing.c
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@ -74,11 +74,23 @@ static void _batadv_update_route(struct batadv_priv *bat_priv,
if (!orig_ifinfo) if (!orig_ifinfo)
return; return;
rcu_read_lock(); spin_lock_bh(&orig_node->neigh_list_lock);
curr_router = rcu_dereference(orig_ifinfo->router); /* curr_router used earlier may not be the current orig_ifinfo->router
if (curr_router && !kref_get_unless_zero(&curr_router->refcount)) * anymore because it was dereferenced outside of the neigh_list_lock
curr_router = NULL; * protected region. After the new best neighbor has replace the current
rcu_read_unlock(); * best neighbor the reference counter needs to decrease. Consequently,
* the code needs to ensure the curr_router variable contains a pointer
* to the replaced best neighbor.
*/
curr_router = rcu_dereference_protected(orig_ifinfo->router, true);
/* increase refcount of new best neighbor */
if (neigh_node)
kref_get(&neigh_node->refcount);
rcu_assign_pointer(orig_ifinfo->router, neigh_node);
spin_unlock_bh(&orig_node->neigh_list_lock);
batadv_orig_ifinfo_put(orig_ifinfo);
/* route deleted */ /* route deleted */
if ((curr_router) && (!neigh_node)) { if ((curr_router) && (!neigh_node)) {
@ -100,27 +112,6 @@ static void _batadv_update_route(struct batadv_priv *bat_priv,
curr_router->addr); curr_router->addr);
} }
if (curr_router)
batadv_neigh_node_put(curr_router);
spin_lock_bh(&orig_node->neigh_list_lock);
/* curr_router used earlier may not be the current orig_ifinfo->router
* anymore because it was dereferenced outside of the neigh_list_lock
* protected region. After the new best neighbor has replace the current
* best neighbor the reference counter needs to decrease. Consequently,
* the code needs to ensure the curr_router variable contains a pointer
* to the replaced best neighbor.
*/
curr_router = rcu_dereference_protected(orig_ifinfo->router, true);
/* increase refcount of new best neighbor */
if (neigh_node)
kref_get(&neigh_node->refcount);
rcu_assign_pointer(orig_ifinfo->router, neigh_node);
spin_unlock_bh(&orig_node->neigh_list_lock);
batadv_orig_ifinfo_put(orig_ifinfo);
/* decrease refcount of previous best neighbor */ /* decrease refcount of previous best neighbor */
if (curr_router) if (curr_router)
batadv_neigh_node_put(curr_router); batadv_neigh_node_put(curr_router);