[v2] batman-adv: Use kref_get for hard_iface subfunctions
Commit Message
The callers of the functions using batadv_hard_iface objects already make
sure that they hold a valid reference. The subfunctions don't have
to check whether the reference counter is > 0 because this was checked by
the callers.
The kref_get function instead WARNs (with debug information) when the
reference counter would still be 0. This makes a bug in batman-adv better
visible because kref_get_unless_zero would have ignored this problem.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
v2:
- Fix imbalance in batadv_iv_ogm_aggregate_new
- Adjust commit message
net/batman-adv/bat_iv_ogm.c | 14 +++-----------
net/batman-adv/hard-interface.c | 7 +++----
net/batman-adv/originator.c | 30 +++++++-----------------------
3 files changed, 13 insertions(+), 38 deletions(-)
Comments
On Monday, April 11, 2016 13:06:40 Sven Eckelmann wrote:
> The callers of the functions using batadv_hard_iface objects already make
> sure that they hold a valid reference. The subfunctions don't have
> to check whether the reference counter is > 0 because this was checked by
> the callers.
>
> The kref_get function instead WARNs (with debug information) when the
> reference counter would still be 0. This makes a bug in batman-adv better
> visible because kref_get_unless_zero would have ignored this problem.
>
> Signed-off-by: Sven Eckelmann <sven@narfation.org>
> ---
> v2:
> - Fix imbalance in batadv_iv_ogm_aggregate_new
> - Adjust commit message
>
> net/batman-adv/bat_iv_ogm.c | 14 +++-----------
> net/batman-adv/hard-interface.c | 7 +++----
> net/batman-adv/originator.c | 30 +++++++-----------------------
> 3 files changed, 13 insertions(+), 38 deletions(-)
Applied in revision 04614cb.
Thanks,
Marek
@@ -679,18 +679,12 @@ static void batadv_iv_ogm_aggregate_new(const unsigned char *packet_buff,
unsigned char *skb_buff;
unsigned int skb_size;
- if (!kref_get_unless_zero(&if_incoming->refcount))
- return;
-
- if (!kref_get_unless_zero(&if_outgoing->refcount))
- goto out_free_incoming;
-
/* own packet should always be scheduled */
if (!own_packet) {
if (!batadv_atomic_dec_not_zero(&bat_priv->batman_queue_left)) {
batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
"batman packet queue full\n");
- goto out_free_outgoing;
+ return;
}
}
@@ -716,6 +710,8 @@ static void batadv_iv_ogm_aggregate_new(const unsigned char *packet_buff,
forw_packet_aggr->packet_len = packet_len;
memcpy(skb_buff, packet_buff, packet_len);
+ kref_get(&if_incoming->refcount);
+ kref_get(&if_outgoing->refcount);
forw_packet_aggr->own = own_packet;
forw_packet_aggr->if_incoming = if_incoming;
forw_packet_aggr->if_outgoing = if_outgoing;
@@ -745,10 +741,6 @@ out_free_forw_packet:
out_nomem:
if (!own_packet)
atomic_inc(&bat_priv->batman_queue_left);
-out_free_outgoing:
- batadv_hardif_put(if_outgoing);
-out_free_incoming:
- batadv_hardif_put(if_incoming);
}
/* aggregate a new packet into the existing ogm packet */
@@ -236,8 +236,8 @@ static void batadv_primary_if_select(struct batadv_priv *bat_priv,
ASSERT_RTNL();
- if (new_hard_iface && !kref_get_unless_zero(&new_hard_iface->refcount))
- new_hard_iface = NULL;
+ if (new_hard_iface)
+ kref_get(&new_hard_iface->refcount);
curr_hard_iface = rcu_dereference_protected(bat_priv->primary_if, 1);
rcu_assign_pointer(bat_priv->primary_if, new_hard_iface);
@@ -464,8 +464,7 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
goto out;
- if (!kref_get_unless_zero(&hard_iface->refcount))
- goto out;
+ kref_get(&hard_iface->refcount);
soft_iface = dev_get_by_name(&init_net, iface_name);
@@ -381,12 +381,8 @@ batadv_orig_ifinfo_new(struct batadv_orig_node *orig_node,
if (!orig_ifinfo)
goto out;
- if (if_outgoing != BATADV_IF_DEFAULT &&
- !kref_get_unless_zero(&if_outgoing->refcount)) {
- kfree(orig_ifinfo);
- orig_ifinfo = NULL;
- goto out;
- }
+ if (if_outgoing != BATADV_IF_DEFAULT)
+ kref_get(&if_outgoing->refcount);
reset_time = jiffies - 1;
reset_time -= msecs_to_jiffies(BATADV_RESET_PROTECTION_MS);
@@ -462,11 +458,8 @@ batadv_neigh_ifinfo_new(struct batadv_neigh_node *neigh,
if (!neigh_ifinfo)
goto out;
- if (if_outgoing && !kref_get_unless_zero(&if_outgoing->refcount)) {
- kfree(neigh_ifinfo);
- neigh_ifinfo = NULL;
- goto out;
- }
+ if (if_outgoing)
+ kref_get(&if_outgoing->refcount);
INIT_HLIST_NODE(&neigh_ifinfo->list);
kref_init(&neigh_ifinfo->refcount);
@@ -539,15 +532,11 @@ batadv_hardif_neigh_create(struct batadv_hard_iface *hard_iface,
if (hardif_neigh)
goto out;
- if (!kref_get_unless_zero(&hard_iface->refcount))
- goto out;
-
hardif_neigh = kzalloc(sizeof(*hardif_neigh), GFP_ATOMIC);
- if (!hardif_neigh) {
- batadv_hardif_put(hard_iface);
+ if (!hardif_neigh)
goto out;
- }
+ kref_get(&hard_iface->refcount);
INIT_HLIST_NODE(&hardif_neigh->list);
ether_addr_copy(hardif_neigh->addr, neigh_addr);
hardif_neigh->if_incoming = hard_iface;
@@ -650,16 +639,11 @@ batadv_neigh_node_new(struct batadv_orig_node *orig_node,
if (!neigh_node)
goto out;
- if (!kref_get_unless_zero(&hard_iface->refcount)) {
- kfree(neigh_node);
- neigh_node = NULL;
- goto out;
- }
-
INIT_HLIST_NODE(&neigh_node->list);
INIT_HLIST_HEAD(&neigh_node->ifinfo_list);
spin_lock_init(&neigh_node->ifinfo_lock);
+ kref_get(&hard_iface->refcount);
ether_addr_copy(neigh_node->addr, neigh_addr);
neigh_node->if_incoming = hard_iface;
neigh_node->orig_node = orig_node;