void addTvlvNode(struct batadv_priv *bat_priv,struct shortTvlv *tvlv){
      struct batadv_shortTvlv_node *tvlv_node;
        tvlv_node=kmalloc(sizeof(struct batadv_shortTvlv_node), GFP_KERNEL);


        if (!tvlv_node)
                return;

        INIT_HLIST_NODE(&tvlv_node->tlist);
        spin_lock_bh(&bat_priv->tvlv_list_lock);
         tvlv_node->sTvlv=tvlv;
         /*not sure for the & in bat priv*/
        hlist_add_head_rcu(&tvlv_node->tlist, &bat_priv->tvlv_list);
        spin_unlock_bh(&bat_priv->tvlv_list_lock);
    }




void registerTvlv(uint8_t type,uint8_t version,uint8_t length,uint8_t *value,struct batadv_priv *bat_priv,struct batadv_ogm_packet *ogm){

    printk("Type %d version %d length %d \n",type,version,length);

    struct batadv_shortTvlv_node *shortTvlv_node;
    struct hlist_node *listnode;
    int new=0;
    uint8_t *val;


    rcu_read_lock();

        hlist_for_each_entry_rcu(shortTvlv_node,listnode,&bat_priv->tvlv_list,tlist){


         if(shortTvlv_node->sTvlv->type!=type )
         continue;

         goto update;

         }

new:
printk("Constructing new one %d\n",sizeof(uint8_t));
struct shortTvlv *tvlv;
tvlv=kmalloc(sizeof(struct shortTvlv)+sizeof(uint8_t),GFP_KERNEL);
        printk("foo\n");
        if(!tvlv)goto end;
        printk("foo\n");
     tvlv->length=length;
     tvlv->version=version;
     tvlv->type=type;
            printk("foo\n");
     ogm->nofAppendedTvlvs++;
            printk("foo\n");
     memcpy(tvlv+sizeof(struct shortTvlv),value,length*sizeof(uint8_t));
            printk("foo\n");
     addTvlvNode(bat_priv,tvlv);

     printk("New Tvlv added: %d\n",ogm->nofAppendedTvlvs);
     goto end;
update:
    printk("updating existing one\n");
    val=value;
    struct shortTvlv *tmp;
    tmp=shortTvlv_node->sTvlv;
    memcpy(tmp+sizeof(struct shortTvlv),val,length*sizeof(uint8_t));

end:
    rcu_read_unlock();

        }


Relevant data structures:
struct shortTvlv {
        uint8_t type;
        uint8_t version;
        uint8_t length;
};


struct batadv_shortTvlv_node {
        struct hlist_node tlist;
        struct rcu_head rcu;
        struct shortTvlv *sTvlv;
};