batman-adv: Check ptr for NULL before reducing its refcnt

The commit b37a46683739 ("netdevice: add the case if dev is NULL") changed
the way how the NULL check for net_devices have to be handled when trying
to reduce its reference counter. Before this commit, it was the
responsibility of the caller to check whether the object is NULL or not.
But it was changed to behave more like kfree. Now the callee has to handle
the NULL-case.

The batman-adv code was scanned via cocinelle for similar places. These
were changed to use the paradigm

  @@
  identifier E, T, R, C;
  identifier put;
  @@
   void put(struct T *E)
   {
  +	if (!E)
  +		return;
  	kref_put(&E->C, R);
   }

Functions which were used in other sources files were moved to the header
to allow the compiler to inline the NULL check and the kref_put call.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

1 files changed, 10 insertions, 12 deletions

diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 711fe5a2cec4..b89a4ed51eb8 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -247,6 +247,9 @@ static void batadv_tt_local_entry_release(struct kref *ref)
 static void
 batadv_tt_local_entry_put(struct batadv_tt_local_entry *tt_local_entry)
 {
+	if (!tt_local_entry)
+		return;
+
 	kref_put(&tt_local_entry->common.refcount,
 		 batadv_tt_local_entry_release);
 }
@@ -270,7 +273,7 @@ static void batadv_tt_global_entry_free_rcu(struct rcu_head *rcu)
  *  queue for free after rcu grace period
  * @ref: kref pointer of the nc_node
  */
-static void batadv_tt_global_entry_release(struct kref *ref)
+void batadv_tt_global_entry_release(struct kref *ref)
 {
 	struct batadv_tt_global_entry *tt_global_entry;
 
@@ -283,17 +286,6 @@ static void batadv_tt_global_entry_release(struct kref *ref)
 }
 
 /**
- * batadv_tt_global_entry_put() - decrement the tt_global_entry refcounter and
- *  possibly release it
- * @tt_global_entry: tt_global_entry to be free'd
- */
-void batadv_tt_global_entry_put(struct batadv_tt_global_entry *tt_global_entry)
-{
-	kref_put(&tt_global_entry->common.refcount,
-		 batadv_tt_global_entry_release);
-}
-
-/**
  * batadv_tt_global_hash_count() - count the number of orig entries
  * @bat_priv: the bat priv with all the soft interface information
  * @addr: the mac address of the client to count entries for
@@ -452,6 +444,9 @@ static void batadv_tt_orig_list_entry_release(struct kref *ref)
 static void
 batadv_tt_orig_list_entry_put(struct batadv_tt_orig_list_entry *orig_entry)
 {
+	if (!orig_entry)
+		return;
+
 	kref_put(&orig_entry->refcount, batadv_tt_orig_list_entry_release);
 }
 
@@ -2603,6 +2598,9 @@ static void batadv_tt_req_node_release(struct kref *ref)
  */
 static void batadv_tt_req_node_put(struct batadv_tt_req_node *tt_req_node)
 {
+	if (!tt_req_node)
+		return;
+
 	kref_put(&tt_req_node->refcount, batadv_tt_req_node_release);
 }