forked from Minki/linux
net: sched: protect filter_chain list with filter_chain_lock mutex
Extend tcf_chain with new filter_chain_lock mutex. Always lock the chain when accessing filter_chain list, instead of relying on rtnl lock. Dereference filter_chain with tcf_chain_dereference() lockdep macro to verify that all users of chain_list have the lock taken. Rearrange tp insert/remove code in tc_new_tfilter/tc_del_tfilter to execute all necessary code while holding chain lock in order to prevent invalidation of chain_info structure by potential concurrent change. This also serializes calls to tcf_chain0_head_change(), which allows head change callbacks to rely on filter_chain_lock for synchronization instead of rtnl mutex. Signed-off-by: Vlad Buslov <vladbu@mellanox.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vlad Buslov
David S. Miller
parent
a5654820bb
commit
ed76f5edcc
@ -341,6 +341,8 @@ struct qdisc_skb_cb {
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typedef void tcf_chain_head_change_t(struct tcf_proto *tp_head, void *priv);
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struct tcf_chain {
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/* Protects filter_chain. */
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struct mutex filter_chain_lock;
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struct tcf_proto __rcu *filter_chain;
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struct list_head list;
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struct tcf_block *block;
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@ -374,6 +376,21 @@ struct tcf_block {
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struct rcu_head rcu;
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};
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#ifdef CONFIG_PROVE_LOCKING
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static inline bool lockdep_tcf_chain_is_locked(struct tcf_chain *chain)
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{
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return lockdep_is_held(&chain->filter_chain_lock);
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}
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#else
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static inline bool lockdep_tcf_chain_is_locked(struct tcf_block *chain)
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{
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return true;
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}
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#endif /* #ifdef CONFIG_PROVE_LOCKING */
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#define tcf_chain_dereference(p, chain) \
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rcu_dereference_protected(p, lockdep_tcf_chain_is_locked(chain))
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static inline void tcf_block_offload_inc(struct tcf_block *block, u32 *flags)
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{
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if (*flags & TCA_CLS_FLAGS_IN_HW)
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@ -221,6 +221,7 @@ static struct tcf_chain *tcf_chain_create(struct tcf_block *block,
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if (!chain)
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return NULL;
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list_add_tail(&chain->list, &block->chain_list);
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mutex_init(&chain->filter_chain_lock);
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chain->block = block;
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chain->index = chain_index;
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chain->refcnt = 1;
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@ -280,6 +281,7 @@ static void tcf_chain_destroy(struct tcf_chain *chain, bool free_block)
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{
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struct tcf_block *block = chain->block;
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mutex_destroy(&chain->filter_chain_lock);
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kfree(chain);
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if (free_block)
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tcf_block_destroy(block);
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@ -443,9 +445,13 @@ static void tcf_chain_put_explicitly_created(struct tcf_chain *chain)
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static void tcf_chain_flush(struct tcf_chain *chain)
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{
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struct tcf_proto *tp = rtnl_dereference(chain->filter_chain);
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struct tcf_proto *tp;
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mutex_lock(&chain->filter_chain_lock);
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tp = tcf_chain_dereference(chain->filter_chain, chain);
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tcf_chain0_head_change(chain, NULL);
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mutex_unlock(&chain->filter_chain_lock);
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while (tp) {
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RCU_INIT_POINTER(chain->filter_chain, tp->next);
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tcf_proto_destroy(tp, NULL);
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@ -785,11 +791,29 @@ tcf_chain0_head_change_cb_add(struct tcf_block *block,
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mutex_lock(&block->lock);
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chain0 = block->chain0.chain;
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if (chain0 && chain0->filter_chain)
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tcf_chain_head_change_item(item, chain0->filter_chain);
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if (chain0)
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tcf_chain_hold(chain0);
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else
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list_add(&item->list, &block->chain0.filter_chain_list);
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mutex_unlock(&block->lock);
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if (chain0) {
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struct tcf_proto *tp_head;
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mutex_lock(&chain0->filter_chain_lock);
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tp_head = tcf_chain_dereference(chain0->filter_chain, chain0);
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if (tp_head)
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tcf_chain_head_change_item(item, tp_head);
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mutex_lock(&block->lock);
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list_add(&item->list, &block->chain0.filter_chain_list);
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mutex_unlock(&block->lock);
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mutex_unlock(&chain0->filter_chain_lock);
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tcf_chain_put(chain0);
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}
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return 0;
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}
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@ -1464,9 +1488,10 @@ struct tcf_chain_info {
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struct tcf_proto __rcu *next;
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};
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static struct tcf_proto *tcf_chain_tp_prev(struct tcf_chain_info *chain_info)
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static struct tcf_proto *tcf_chain_tp_prev(struct tcf_chain *chain,
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struct tcf_chain_info *chain_info)
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{
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return rtnl_dereference(*chain_info->pprev);
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return tcf_chain_dereference(*chain_info->pprev, chain);
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}
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static void tcf_chain_tp_insert(struct tcf_chain *chain,
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@ -1475,7 +1500,7 @@ static void tcf_chain_tp_insert(struct tcf_chain *chain,
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{
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if (*chain_info->pprev == chain->filter_chain)
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tcf_chain0_head_change(chain, tp);
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RCU_INIT_POINTER(tp->next, tcf_chain_tp_prev(chain_info));
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RCU_INIT_POINTER(tp->next, tcf_chain_tp_prev(chain, chain_info));
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rcu_assign_pointer(*chain_info->pprev, tp);
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tcf_chain_hold(chain);
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}
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@ -1484,7 +1509,7 @@ static void tcf_chain_tp_remove(struct tcf_chain *chain,
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struct tcf_chain_info *chain_info,
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struct tcf_proto *tp)
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{
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struct tcf_proto *next = rtnl_dereference(chain_info->next);
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struct tcf_proto *next = tcf_chain_dereference(chain_info->next, chain);
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if (tp == chain->filter_chain)
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tcf_chain0_head_change(chain, next);
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@ -1502,7 +1527,8 @@ static struct tcf_proto *tcf_chain_tp_find(struct tcf_chain *chain,
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/* Check the chain for existence of proto-tcf with this priority */
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for (pprev = &chain->filter_chain;
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(tp = rtnl_dereference(*pprev)); pprev = &tp->next) {
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(tp = tcf_chain_dereference(*pprev, chain));
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pprev = &tp->next) {
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if (tp->prio >= prio) {
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if (tp->prio == prio) {
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if (prio_allocate ||
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@ -1710,12 +1736,13 @@ replay:
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goto errout;
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}
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mutex_lock(&chain->filter_chain_lock);
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tp = tcf_chain_tp_find(chain, &chain_info, protocol,
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prio, prio_allocate);
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if (IS_ERR(tp)) {
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NL_SET_ERR_MSG(extack, "Filter with specified priority/protocol not found");
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err = PTR_ERR(tp);
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goto errout;
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goto errout_locked;
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}
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if (tp == NULL) {
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@ -1724,29 +1751,37 @@ replay:
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if (tca[TCA_KIND] == NULL || !protocol) {
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NL_SET_ERR_MSG(extack, "Filter kind and protocol must be specified");
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err = -EINVAL;
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goto errout;
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goto errout_locked;
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}
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if (!(n->nlmsg_flags & NLM_F_CREATE)) {
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NL_SET_ERR_MSG(extack, "Need both RTM_NEWTFILTER and NLM_F_CREATE to create a new filter");
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err = -ENOENT;
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goto errout;
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goto errout_locked;
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}
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if (prio_allocate)
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prio = tcf_auto_prio(tcf_chain_tp_prev(&chain_info));
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prio = tcf_auto_prio(tcf_chain_tp_prev(chain,
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&chain_info));
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mutex_unlock(&chain->filter_chain_lock);
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tp = tcf_proto_create(nla_data(tca[TCA_KIND]),
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protocol, prio, chain, extack);
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if (IS_ERR(tp)) {
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err = PTR_ERR(tp);
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goto errout;
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}
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mutex_lock(&chain->filter_chain_lock);
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tcf_chain_tp_insert(chain, &chain_info, tp);
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mutex_unlock(&chain->filter_chain_lock);
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tp_created = 1;
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} else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) {
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NL_SET_ERR_MSG(extack, "Specified filter kind does not match existing one");
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err = -EINVAL;
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goto errout;
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goto errout_locked;
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} else {
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mutex_unlock(&chain->filter_chain_lock);
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}
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fh = tp->ops->get(tp, t->tcm_handle);
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@ -1772,15 +1807,11 @@ replay:
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err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh,
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n->nlmsg_flags & NLM_F_CREATE ? TCA_ACT_NOREPLACE : TCA_ACT_REPLACE,
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extack);
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if (err == 0) {
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if (tp_created)
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tcf_chain_tp_insert(chain, &chain_info, tp);
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if (err == 0)
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tfilter_notify(net, skb, n, tp, block, q, parent, fh,
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RTM_NEWTFILTER, false);
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} else {
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if (tp_created)
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else if (tp_created)
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tcf_proto_destroy(tp, NULL);
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}
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errout:
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if (chain)
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@ -1790,6 +1821,10 @@ errout:
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/* Replay the request. */
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goto replay;
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return err;
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errout_locked:
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mutex_unlock(&chain->filter_chain_lock);
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goto errout;
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}
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static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
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@ -1865,31 +1900,34 @@ static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
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goto errout;
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}
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mutex_lock(&chain->filter_chain_lock);
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tp = tcf_chain_tp_find(chain, &chain_info, protocol,
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prio, false);
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if (!tp || IS_ERR(tp)) {
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NL_SET_ERR_MSG(extack, "Filter with specified priority/protocol not found");
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err = tp ? PTR_ERR(tp) : -ENOENT;
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goto errout;
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goto errout_locked;
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} else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) {
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NL_SET_ERR_MSG(extack, "Specified filter kind does not match existing one");
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err = -EINVAL;
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goto errout;
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}
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fh = tp->ops->get(tp, t->tcm_handle);
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if (!fh) {
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if (t->tcm_handle == 0) {
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goto errout_locked;
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} else if (t->tcm_handle == 0) {
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tcf_chain_tp_remove(chain, &chain_info, tp);
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mutex_unlock(&chain->filter_chain_lock);
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tfilter_notify(net, skb, n, tp, block, q, parent, fh,
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RTM_DELTFILTER, false);
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tcf_proto_destroy(tp, extack);
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err = 0;
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} else {
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goto errout;
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}
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mutex_unlock(&chain->filter_chain_lock);
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fh = tp->ops->get(tp, t->tcm_handle);
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if (!fh) {
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NL_SET_ERR_MSG(extack, "Specified filter handle not found");
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err = -ENOENT;
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}
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} else {
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bool last;
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@ -1899,7 +1937,10 @@ static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
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if (err)
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goto errout;
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if (last) {
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mutex_lock(&chain->filter_chain_lock);
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tcf_chain_tp_remove(chain, &chain_info, tp);
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mutex_unlock(&chain->filter_chain_lock);
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tcf_proto_destroy(tp, extack);
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}
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}
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@ -1909,6 +1950,10 @@ errout:
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tcf_chain_put(chain);
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tcf_block_release(q, block);
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return err;
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errout_locked:
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mutex_unlock(&chain->filter_chain_lock);
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goto errout;
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}
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static int tc_get_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
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@ -1966,8 +2011,10 @@ static int tc_get_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
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goto errout;
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}
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mutex_lock(&chain->filter_chain_lock);
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tp = tcf_chain_tp_find(chain, &chain_info, protocol,
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prio, false);
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mutex_unlock(&chain->filter_chain_lock);
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if (!tp || IS_ERR(tp)) {
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NL_SET_ERR_MSG(extack, "Filter with specified priority/protocol not found");
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err = tp ? PTR_ERR(tp) : -ENOENT;
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@ -1366,7 +1366,11 @@ static void mini_qdisc_rcu_func(struct rcu_head *head)
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void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp,
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struct tcf_proto *tp_head)
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{
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struct mini_Qdisc *miniq_old = rtnl_dereference(*miniqp->p_miniq);
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/* Protected with chain0->filter_chain_lock.
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* Can't access chain directly because tp_head can be NULL.
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*/
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struct mini_Qdisc *miniq_old =
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rcu_dereference_protected(*miniqp->p_miniq, 1);
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struct mini_Qdisc *miniq;
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if (!tp_head) {
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