diff options
| author |   Sven Eckelmann <sven@narfation.org> | 2018-10-30 22:01:23 +0100 |
|---|---|---|
| committer |   Simon Wunderlich <sw@simonwunderlich.de> | 2018-11-12 10:41:51 +0100 |
| commit | 9264c85c8b42d76862ae4ed307f4523e8bbab100 (patch) | |
| tree | 0dbeb5eec786a78ebbd936bdb5a2aa66f41b08cc /net/batman-adv/gateway_client.c | |
| parent | batman-adv: Fix description for BATMAN_ADV_DEBUG (diff) | |
| download | linux-dev-9264c85c8b42d76862ae4ed307f4523e8bbab100.tar.xz linux-dev-9264c85c8b42d76862ae4ed307f4523e8bbab100.zip | |
batman-adv: Add inconsistent gateway netlink dump detection
The netlink dump functionality transfers a large number of entries from the
kernel to userspace. It is rather likely that the transfer has to
interrupted and later continued. During that time, it can happen that
either new entries are added or removed. The userspace could than either
receive some entries multiple times or miss entries.
Commit 670dc2833d14 ("netlink: advertise incomplete dumps") introduced a
mechanism to inform userspace about this problem. Userspace can then decide
whether it is necessary or not to retry dumping the information again.
The netlink dump functions have to be switched to exclusive locks to avoid
changes while the current message is prepared. And an external generation
sequence counter is introduced which tracks all modifications of the list.
Reported-by: Matthias Schiffer <mschiffer@universe-factory.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Diffstat (limited to 'net/batman-adv/gateway_client.c')
| -rw-r--r-- | net/batman-adv/gateway_client.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c index 140c61a3f1ec..9d8e5eda2314 100644 --- a/net/batman-adv/gateway_client.c +++ b/net/batman-adv/gateway_client.c @@ -377,6 +377,7 @@ static void batadv_gw_node_add(struct batadv_priv *bat_priv, kref_get(&gw_node->refcount); hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.gateway_list); + bat_priv->gw.generation++; batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n", @@ -472,6 +473,7 @@ void batadv_gw_node_update(struct batadv_priv *bat_priv, if (!hlist_unhashed(&gw_node->list)) { hlist_del_init_rcu(&gw_node->list); batadv_gw_node_put(gw_node); + bat_priv->gw.generation++; } spin_unlock_bh(&bat_priv->gw.list_lock); @@ -518,6 +520,7 @@ void batadv_gw_node_free(struct batadv_priv *bat_priv) &bat_priv->gw.gateway_list, list) { hlist_del_init_rcu(&gw_node->list); batadv_gw_node_put(gw_node); + bat_priv->gw.generation++; } spin_unlock_bh(&bat_priv->gw.list_lock); } |