[B.A.T.M.A.N.] [PATCHv4 next 02/11] batman-adv: don't mess up with the netdev refcounting if not needed

Antonio Quartulli
2014-03-19T17:55:38Z

Looking for an interface and increasing its refcounter only
to check if it really exists is not really useful and makes
the code look more complex without a real gain.

Change batadv_mcast_has_bridge() accordingly and avoid to
use the pointer to the interface outside of the
rcu_read_lock/unlock context.

Introduced by e368857f66620b8483166e8e6556d9c87f9b3e71
("batman-adv: Multicast Listener Announcements via Translation Table")

Cc: Linus Lüssing <linus.luessing@web.de>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
---
compat.h | 19 ++++---------------
multicast.c | 33 ++++-----------------------------
2 files changed, 8 insertions(+), 44 deletions(-)

diff --git a/compat.h b/compat.h
index e14c6bb..5eb5fe6 100644
--- a/compat.h
+++ b/compat.h
@@ -164,14 +164,8 @@ static inline int batadv_param_set_copystring(const char *val,
#define NET_ADDR_RANDOM 0

#define netdev_master_upper_dev_get_rcu(dev) \
- upper; \
- if (dev->br_port ? 1 : 0) { \
- rcu_read_unlock(); \
- dev_hold(dev); \
- return dev; \
- } else {\
- dev = NULL; \
- }
+ (dev->br_port ? dev : NULL); \
+ break;

#endif /* < KERNEL_VERSION(2, 6, 36) */

@@ -375,13 +369,8 @@ static int __batadv_interface_tx(struct sk_buff *skb, \

#ifndef netdev_master_upper_dev_get_rcu
#define netdev_master_upper_dev_get_rcu(dev) \
- upper; \
- if (dev->priv_flags & IFF_BRIDGE_PORT) { \
- rcu_read_unlock(); \
- dev_hold(dev); \
- return dev; \
- } else \
- dev = NULL;
+ (dev->priv_flags & IFF_BRIDGE_PORT ? dev : NULL); \
+ break;

#endif /* netdev_master_upper_dev_get_rcu */

diff --git a/multicast.c b/multicast.c
index d92de1e..edce295 100644
--- a/multicast.c
+++ b/multicast.c
@@ -156,51 +156,26 @@ static void batadv_mcast_mla_tt_add(struct batadv_priv *bat_priv,
}

/**
- * batadv_mcast_get_bridge - get the bridge interface on our soft interface
+ * batadv_mcast_has_bridge - check whether the soft-iface is bridged
* @bat_priv: the bat priv with all the soft interface information
*
- * Return the next bridge interface on top of our soft interface and increase
- * its refcount. If no such bridge interface exists, then return NULL.
+ * Check whether there is a bridge on top of our soft interface. Return
+ * true if so, false otherwise.
*/
-static struct net_device *
-batadv_mcast_get_bridge(struct batadv_priv *bat_priv)
+static bool batadv_mcast_has_bridge(struct batadv_priv *bat_priv)
{
struct net_device *upper = bat_priv->soft_iface;

rcu_read_lock();
-
do {
upper = netdev_master_upper_dev_get_rcu(upper);
} while (upper && !(upper->priv_flags & IFF_EBRIDGE));
-
- if (upper)
- dev_hold(upper);
-
rcu_read_unlock();

return upper;
}

/**
- * batadv_mcast_has_bridge - check whether the soft-iface is bridged
- * @bat_priv: the bat priv with all the soft interface information
- *
- * Check whether there is a bridge on top of our soft interface. Return
- * true if so, false otherwise.
- */
-static bool batadv_mcast_has_bridge(struct batadv_priv *bat_priv)
-{
- struct net_device *bridge;
-
- bridge = batadv_mcast_get_bridge(bat_priv);
- if (!bridge)
- return false;
-
- dev_put(bridge);
- return true;
-}
-
-/**
* batadv_mcast_mla_tvlv_update - update multicast tvlv
* @bat_priv: the bat priv with all the soft interface information
*
--
1.8.3.2