diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h index a3101582f642..6d02f31abba8 100644 --- a/include/net/pkt_cls.h +++ b/include/net/pkt_cls.h @@ -39,7 +39,10 @@ bool tcf_queue_work(struct rcu_work *rwork, work_func_t func); #ifdef CONFIG_NET_CLS struct tcf_chain *tcf_chain_get(struct tcf_block *block, u32 chain_index, bool create); +struct tcf_chain *tcf_chain_get_by_act(struct tcf_block *block, + u32 chain_index); void tcf_chain_put(struct tcf_chain *chain); +void tcf_chain_put_by_act(struct tcf_chain *chain); void tcf_block_netif_keep_dst(struct tcf_block *block); int tcf_block_get(struct tcf_block **p_block, struct tcf_proto __rcu **p_filter_chain, struct Qdisc *q, diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index 085c509c8674..c5432362dc26 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -314,6 +314,7 @@ struct tcf_chain { struct tcf_block *block; u32 index; /* chain index */ unsigned int refcnt; + unsigned int action_refcnt; bool explicitly_created; const struct tcf_proto_ops *tmplt_ops; void *tmplt_priv; diff --git a/net/sched/act_api.c b/net/sched/act_api.c index 148a89ab789b..b43df1e25c6d 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -36,7 +36,7 @@ static int tcf_action_goto_chain_init(struct tc_action *a, struct tcf_proto *tp) if (!tp) return -EINVAL; - a->goto_chain = tcf_chain_get(tp->chain->block, chain_index, true); + a->goto_chain = tcf_chain_get_by_act(tp->chain->block, chain_index); if (!a->goto_chain) return -ENOMEM; return 0; @@ -44,7 +44,7 @@ static int tcf_action_goto_chain_init(struct tc_action *a, struct tcf_proto *tp) static void tcf_action_goto_chain_fini(struct tc_action *a) { - tcf_chain_put(a->goto_chain); + tcf_chain_put_by_act(a->goto_chain); } static void tcf_action_goto_chain_exec(const struct tc_action *a, diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 75cce2819de9..e20aad1987b8 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -262,6 +262,25 @@ static void tcf_chain_hold(struct tcf_chain *chain) ++chain->refcnt; } +static void tcf_chain_hold_by_act(struct tcf_chain *chain) +{ + ++chain->action_refcnt; +} + +static void tcf_chain_release_by_act(struct tcf_chain *chain) +{ + --chain->action_refcnt; +} + +static bool tcf_chain_is_zombie(struct tcf_chain *chain) +{ + /* In case all the references are action references, this + * chain is a zombie and should not be listed in the chain + * dump list. + */ + return chain->refcnt == chain->action_refcnt; +} + static struct tcf_chain *tcf_chain_lookup(struct tcf_block *block, u32 chain_index) { @@ -298,6 +317,15 @@ struct tcf_chain *tcf_chain_get(struct tcf_block *block, u32 chain_index, } EXPORT_SYMBOL(tcf_chain_get); +struct tcf_chain *tcf_chain_get_by_act(struct tcf_block *block, u32 chain_index) +{ + struct tcf_chain *chain = tcf_chain_get(block, chain_index, true); + + tcf_chain_hold_by_act(chain); + return chain; +} +EXPORT_SYMBOL(tcf_chain_get_by_act); + static void tc_chain_tmplt_del(struct tcf_chain *chain); void tcf_chain_put(struct tcf_chain *chain) @@ -310,6 +338,13 @@ void tcf_chain_put(struct tcf_chain *chain) } EXPORT_SYMBOL(tcf_chain_put); +void tcf_chain_put_by_act(struct tcf_chain *chain) +{ + tcf_chain_release_by_act(chain); + tcf_chain_put(chain); +} +EXPORT_SYMBOL(tcf_chain_put_by_act); + static void tcf_chain_put_explicitly_created(struct tcf_chain *chain) { if (chain->explicitly_created) @@ -1803,20 +1838,29 @@ replay: chain = tcf_chain_lookup(block, chain_index); if (n->nlmsg_type == RTM_NEWCHAIN) { if (chain) { - NL_SET_ERR_MSG(extack, "Filter chain already exists"); - return -EEXIST; - } - if (!(n->nlmsg_flags & NLM_F_CREATE)) { - NL_SET_ERR_MSG(extack, "Need both RTM_NEWCHAIN and NLM_F_CREATE to create a new chain"); - return -ENOENT; - } - chain = tcf_chain_create(block, chain_index); - if (!chain) { - NL_SET_ERR_MSG(extack, "Failed to create filter chain"); - return -ENOMEM; + if (tcf_chain_is_zombie(chain)) { + /* The chain exists only because there is + * some action referencing it, meaning it + * is a zombie. + */ + tcf_chain_hold(chain); + } else { + NL_SET_ERR_MSG(extack, "Filter chain already exists"); + return -EEXIST; + } + } else { + if (!(n->nlmsg_flags & NLM_F_CREATE)) { + NL_SET_ERR_MSG(extack, "Need both RTM_NEWCHAIN and NLM_F_CREATE to create a new chain"); + return -ENOENT; + } + chain = tcf_chain_create(block, chain_index); + if (!chain) { + NL_SET_ERR_MSG(extack, "Failed to create filter chain"); + return -ENOMEM; + } } } else { - if (!chain) { + if (!chain || tcf_chain_is_zombie(chain)) { NL_SET_ERR_MSG(extack, "Cannot find specified filter chain"); return -EINVAL; } @@ -1944,6 +1988,8 @@ static int tc_dump_chain(struct sk_buff *skb, struct netlink_callback *cb) index++; continue; } + if (tcf_chain_is_zombie(chain)) + continue; err = tc_chain_fill_node(chain, net, skb, block, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, NLM_F_MULTI,