diff mbox

[v2,06/18] batman-adv: Place kref_get for orig_node near use

Message ID 1468597173-25378-6-git-send-email-sven@narfation.org (mailing list archive)
State Accepted, archived
Commit de6330c9b8b50c9373dfda64c236e06dec86657e
Delegated to: Marek Lindner
Headers

Commit Message

Sven Eckelmann July 15, 2016, 3:39 p.m. UTC 
  It is hard to understand why the refcnt is increased when it isn't done
near the actual place the new reference is used. So using kref_get right
before the place which requires the reference and in the same function
helps to avoid accidental problems causedy incorrect reference counting.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
v2:
 - split patch based on type

 net/batman-adv/bat_iv_ogm.c     | 7 ++++---
 net/batman-adv/bat_v_ogm.c      | 5 ++---
 net/batman-adv/gateway_client.c | 2 +-
 net/batman-adv/network-coding.c | 7 +++----
 net/batman-adv/originator.c     | 1 -
 5 files changed, 10 insertions(+), 12 deletions(-)

Comments

Marek Lindner July 19, 2016, 8:25 a.m. UTC | #1 
On Friday, July 15, 2016 17:39:21 Sven Eckelmann wrote:
> It is hard to understand why the refcnt is increased when it isn't done
> near the actual place the new reference is used. So using kref_get right
> before the place which requires the reference and in the same function
> helps to avoid accidental problems causedy incorrect reference counting.
> 
> Signed-off-by: Sven Eckelmann <sven@narfation.org>
> ---
> v2:
>  - split patch based on type
> 
>  net/batman-adv/bat_iv_ogm.c     | 7 ++++---
>  net/batman-adv/bat_v_ogm.c      | 5 ++---
>  net/batman-adv/gateway_client.c | 2 +-
>  net/batman-adv/network-coding.c | 7 +++----
>  net/batman-adv/originator.c     | 1 -
>  5 files changed, 10 insertions(+), 12 deletions(-)

Applied in revision de6330c.

Thanks,
Marek
diff mbox

Patch

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index a40cdf2..4e84dbc 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -319,17 +319,18 @@  batadv_iv_ogm_orig_get(struct batadv_priv *bat_priv, const u8 *addr)
 	if (!orig_node->bat_iv.bcast_own_sum)
 		goto free_orig_node;
 
+	kref_get(&orig_node->refcount);
 	hash_added = batadv_hash_add(bat_priv->orig_hash, batadv_compare_orig,
 				     batadv_choose_orig, orig_node,
 				     &orig_node->hash_entry);
 	if (hash_added != 0)
-		goto free_orig_node;
+		goto free_orig_node_hash;
 
 	return orig_node;
 
-free_orig_node:
-	/* free twice, as batadv_orig_node_new sets refcount to 2 */
+free_orig_node_hash:
 	batadv_orig_node_put(orig_node);
+free_orig_node:
 	batadv_orig_node_put(orig_node);
 
 	return NULL;
diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c
index 6fbba4e..1aeeadc 100644
--- a/net/batman-adv/bat_v_ogm.c
+++ b/net/batman-adv/bat_v_ogm.c
@@ -73,13 +73,12 @@  struct batadv_orig_node *batadv_v_ogm_orig_get(struct batadv_priv *bat_priv,
 	if (!orig_node)
 		return NULL;
 
+	kref_get(&orig_node->refcount);
 	hash_added = batadv_hash_add(bat_priv->orig_hash, batadv_compare_orig,
 				     batadv_choose_orig, orig_node,
 				     &orig_node->hash_entry);
 	if (hash_added != 0) {
-		/* orig_node->refcounter is initialised to 2 by
-		 * batadv_orig_node_new()
-		 */
+		/* remove refcnt for newly created orig_node and hash entry */
 		batadv_orig_node_put(orig_node);
 		batadv_orig_node_put(orig_node);
 		orig_node = NULL;
diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
index a77a179..94f8f9d 100644
--- a/net/batman-adv/gateway_client.c
+++ b/net/batman-adv/gateway_client.c
@@ -333,8 +333,8 @@  static void batadv_gw_node_add(struct batadv_priv *bat_priv,
 	if (!gw_node)
 		return;
 
-	kref_get(&orig_node->refcount);
 	INIT_HLIST_NODE(&gw_node->list);
+	kref_get(&orig_node->refcount);
 	gw_node->orig_node = orig_node;
 	gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
 	gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
diff --git a/net/batman-adv/network-coding.c b/net/batman-adv/network-coding.c
index 293ef4f..3814cfb 100644
--- a/net/batman-adv/network-coding.c
+++ b/net/batman-adv/network-coding.c
@@ -856,14 +856,13 @@  batadv_nc_get_nc_node(struct batadv_priv *bat_priv,
 	if (!nc_node)
 		return NULL;
 
-	kref_get(&orig_neigh_node->refcount);
-
 	/* Initialize nc_node */
 	INIT_LIST_HEAD(&nc_node->list);
-	ether_addr_copy(nc_node->addr, orig_node->orig);
-	nc_node->orig_node = orig_neigh_node;
 	kref_init(&nc_node->refcount);
 	kref_get(&nc_node->refcount);
+	ether_addr_copy(nc_node->addr, orig_node->orig);
+	kref_get(&orig_neigh_node->refcount);
+	nc_node->orig_node = orig_neigh_node;
 
 	/* Select ingoing or outgoing coding node */
 	if (in_coding) {
diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 3bf3065..8208276 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -906,7 +906,6 @@  struct batadv_orig_node *batadv_orig_node_new(struct batadv_priv *bat_priv,
 
 	/* extra reference for return */
 	kref_init(&orig_node->refcount);
-	kref_get(&orig_node->refcount);
 
 	orig_node->bat_priv = bat_priv;
 	ether_addr_copy(orig_node->orig, addr);