From c7c32e72cbe23cea97c5d87ffcf6e23cc1ec1a65 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Thu, 10 Apr 2014 00:31:10 +0200 Subject: [PATCH] netfilter: nf_tables: defer all object release via rcu Now that all objects are released in the reverse order via the transaction infrastructure, we can enqueue the release via call_rcu to save one synchronize_rcu. For small rule-sets loaded via nft -f, it now takes around 50ms less here. Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_tables.h | 2 + net/netfilter/nf_tables_api.c | 93 ++++++++++++++++++------------- 2 files changed, 56 insertions(+), 39 deletions(-) diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index 1ed2797fb964..7ee6ce6564ae 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -393,12 +393,14 @@ struct nft_rule { /** * struct nft_trans - nf_tables object update in transaction * + * @rcu_head: rcu head to defer release of transaction data * @list: used internally * @msg_type: message type * @ctx: transaction context * @data: internal information related to the transaction */ struct nft_trans { + struct rcu_head rcu_head; struct list_head list; int msg_type; struct nft_ctx ctx; diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 4147166ad17c..e171c635d08c 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -3298,6 +3298,30 @@ static void nft_chain_commit_update(struct nft_trans *trans) } } +/* Schedule objects for release via rcu to make sure no packets are accesing + * removed rules. + */ +static void nf_tables_commit_release_rcu(struct rcu_head *rt) +{ + struct nft_trans *trans = container_of(rt, struct nft_trans, rcu_head); + + switch (trans->msg_type) { + case NFT_MSG_DELTABLE: + nf_tables_table_destroy(&trans->ctx); + break; + case NFT_MSG_DELCHAIN: + nf_tables_chain_destroy(trans->ctx.chain); + break; + case NFT_MSG_DELRULE: + nf_tables_rule_destroy(&trans->ctx, nft_trans_rule(trans)); + break; + case NFT_MSG_DELSET: + nft_set_destroy(nft_trans_set(trans)); + break; + } + kfree(trans); +} + static int nf_tables_commit(struct sk_buff *skb) { struct net *net = sock_net(skb->sk); @@ -3397,32 +3421,39 @@ static int nf_tables_commit(struct sk_buff *skb) } } - /* Make sure we don't see any packet traversing old rules */ - synchronize_rcu(); - - /* Now we can safely release unused old rules */ list_for_each_entry_safe(trans, next, &net->nft.commit_list, list) { - switch (trans->msg_type) { - case NFT_MSG_DELTABLE: - nf_tables_table_destroy(&trans->ctx); - break; - case NFT_MSG_DELCHAIN: - nf_tables_chain_destroy(trans->ctx.chain); - break; - case NFT_MSG_DELRULE: - nf_tables_rule_destroy(&trans->ctx, - nft_trans_rule(trans)); - break; - case NFT_MSG_DELSET: - nft_set_destroy(nft_trans_set(trans)); - break; - } - nft_trans_destroy(trans); + list_del(&trans->list); + trans->ctx.nla = NULL; + call_rcu(&trans->rcu_head, nf_tables_commit_release_rcu); } return 0; } +/* Schedule objects for release via rcu to make sure no packets are accesing + * aborted rules. + */ +static void nf_tables_abort_release_rcu(struct rcu_head *rt) +{ + struct nft_trans *trans = container_of(rt, struct nft_trans, rcu_head); + + switch (trans->msg_type) { + case NFT_MSG_NEWTABLE: + nf_tables_table_destroy(&trans->ctx); + break; + case NFT_MSG_NEWCHAIN: + nf_tables_chain_destroy(trans->ctx.chain); + break; + case NFT_MSG_NEWRULE: + nf_tables_rule_destroy(&trans->ctx, nft_trans_rule(trans)); + break; + case NFT_MSG_NEWSET: + nft_set_destroy(nft_trans_set(trans)); + break; + } + kfree(trans); +} + static int nf_tables_abort(struct sk_buff *skb) { struct net *net = sock_net(skb->sk); @@ -3495,26 +3526,10 @@ static int nf_tables_abort(struct sk_buff *skb) } } - /* Make sure we don't see any packet accessing aborted rules */ - synchronize_rcu(); - list_for_each_entry_safe(trans, next, &net->nft.commit_list, list) { - switch (trans->msg_type) { - case NFT_MSG_NEWTABLE: - nf_tables_table_destroy(&trans->ctx); - break; - case NFT_MSG_NEWCHAIN: - nf_tables_chain_destroy(trans->ctx.chain); - break; - case NFT_MSG_NEWRULE: - nf_tables_rule_destroy(&trans->ctx, - nft_trans_rule(trans)); - break; - case NFT_MSG_NEWSET: - nft_set_destroy(nft_trans_set(trans)); - break; - } - nft_trans_destroy(trans); + list_del(&trans->list); + trans->ctx.nla = NULL; + call_rcu(&trans->rcu_head, nf_tables_abort_release_rcu); } return 0; -- 2.20.1