rcu学习心得

来源：百度文库编辑：神马文学网时间：2024/04/28 06:10:08

void __dev_remove_pack(struct packet_type *pt)
{
struct list_head *head;
struct packet_type *pt1; spin_lock_bh(&ptype_lock); if (pt->type == htons(ETH_P_ALL))
  head = &ptype_all;
else
  head = &ptype_base[ntohs(pt->type) & PTYPE_HASH_MASK]; list_for_each_entry(pt1, head, list) {
  if (pt == pt1) {
   list_del_rcu(&pt->list);
   goto out;
  }
} printk(KERN_WARNING "dev_remove_pack: %p not found.\n", pt);
out:
spin_unlock_bh(&ptype_lock);
} 从上面的代码看出，当需要遍历删除hash表的时候，只需要在相应的桶上加写锁就可以了， spin_lock_bh(&ptype_lock); 在读取的时候需要加上读临界锁就可以了   static void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)
{
struct packet_type *ptype;#ifdef CONFIG_NET_CLS_ACT
if (!(skb->tstamp.tv64 && (G_TC_FROM(skb->tc_verd) & AT_INGRESS)))
  net_timestamp(skb);
#else
net_timestamp(skb);
#endif rcu_read_lock();
list_for_each_entry_rcu(ptype, &ptype_all, list) {
  /* Never send packets back to the socket
   * they originated from - MvS (miquels@drinkel.ow.org)
   */
  if ((ptype->dev == dev || !ptype->dev) &&
      (ptype->af_packet_priv == NULL ||
       (struct sock *)ptype->af_packet_priv != skb->sk)) {
   struct sk_buff *skb2= skb_clone(skb, GFP_ATOMIC);
   if (!skb2)
    break;   /* skb->nh should be correctly
      set by sender, so that the second statement is
      just protection against buggy protocols.
    */
   skb_reset_mac_header(skb2);   if (skb_network_header(skb2) < skb2->data ||
       skb2->network_header > skb2->tail) {
    if (net_ratelimit())
     printk(KERN_CRIT "protocol %04x is "
            "buggy, dev %s\n",
            skb2->protocol, dev->name);
    skb_reset_network_header(skb2);
   }   skb2->transport_header = skb2->network_header;
   skb2->pkt_type = PACKET_OUTGOING;
   ptype->func(skb2, skb->dev, ptype, skb->dev);
  }
}
rcu_read_unlock();
}

rcu学习心得 RCU writer 学习心得学习心得学习心得学习心得学习心得学习心得学习心得学习心得学习心得学习心得学习心得学习心得 Linux中RCU机制的原理 JSP学习心得 ETL学习心得中央经济工作会议学习心得英语学习心得会计职称学习心得学习心得2 学习心得体会 - 学习方法 - 学习心得 - 雅思学习心得