From 276472eae063d717b775fdfc87529937402d0e08 Mon Sep 17 00:00:00 2001 From: Julian Anastasov Date: Thu, 21 Mar 2013 11:58:08 +0200 Subject: [PATCH] ipvs: remove rs_lock by using RCU rs_lock was used to protect rs_table (hash table) from updaters (under global mutex) and readers (packet handlers). We can remove rs_lock by using RCU lock for readers. Reclaiming dest only with kfree_rcu is enough because the readers access only fields from the ip_vs_dest structure. Use hlist for rs_table. As we are now using hlist_del_rcu, introduce in_rs_table flag as replacement for the list_empty checks which do not work with RCU. It is needed because only NAT dests are in the rs_table. Signed-off-by: Julian Anastasov Signed-off by: Hans Schillstrom Signed-off-by: Simon Horman --- include/net/ip_vs.h | 14 +++--- net/netfilter/ipvs/ip_vs_core.c | 5 +- net/netfilter/ipvs/ip_vs_ctl.c | 88 ++++++++++++--------------------- 3 files changed, 41 insertions(+), 66 deletions(-) diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h index 84ca17141a44..b06aa6c939fa 100644 --- a/include/net/ip_vs.h +++ b/include/net/ip_vs.h @@ -738,7 +738,7 @@ struct ip_vs_dest_dst { */ struct ip_vs_dest { struct list_head n_list; /* for the dests in the service */ - struct list_head d_list; /* for table with all the dests */ + struct hlist_node d_list; /* for table with all the dests */ u16 af; /* address family */ __be16 port; /* port number of the server */ @@ -767,6 +767,9 @@ struct ip_vs_dest { __be16 vport; /* virtual port number */ union nf_inet_addr vaddr; /* virtual IP address */ __u32 vfwmark; /* firewall mark of service */ + + struct rcu_head rcu_head; + unsigned int in_rs_table:1; /* we are in rs_table */ }; @@ -897,7 +900,7 @@ struct netns_ipvs { #define IP_VS_RTAB_SIZE (1 << IP_VS_RTAB_BITS) #define IP_VS_RTAB_MASK (IP_VS_RTAB_SIZE - 1) - struct list_head rs_table[IP_VS_RTAB_SIZE]; + struct hlist_head rs_table[IP_VS_RTAB_SIZE]; /* ip_vs_app */ struct list_head app_list; /* ip_vs_proto */ @@ -933,7 +936,6 @@ struct netns_ipvs { int num_services; /* no of virtual services */ - rwlock_t rs_lock; /* real services table */ /* Trash for destinations */ struct list_head dest_trash; /* Service counters */ @@ -1376,9 +1378,9 @@ static inline void ip_vs_service_put(struct ip_vs_service *svc) atomic_dec(&svc->usecnt); } -extern struct ip_vs_dest * -ip_vs_lookup_real_service(struct net *net, int af, __u16 protocol, - const union nf_inet_addr *daddr, __be16 dport); +extern bool +ip_vs_has_real_service(struct net *net, int af, __u16 protocol, + const union nf_inet_addr *daddr, __be16 dport); extern int ip_vs_use_count_inc(void); extern void ip_vs_use_count_dec(void); diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c index 6ad24e7ef440..4fc749c6ec27 100644 --- a/net/netfilter/ipvs/ip_vs_core.c +++ b/net/netfilter/ipvs/ip_vs_core.c @@ -1161,9 +1161,8 @@ ip_vs_out(unsigned int hooknum, struct sk_buff *skb, int af) sizeof(_ports), _ports, &iph); if (pptr == NULL) return NF_ACCEPT; /* Not for me */ - if (ip_vs_lookup_real_service(net, af, iph.protocol, - &iph.saddr, - pptr[0])) { + if (ip_vs_has_real_service(net, af, iph.protocol, &iph.saddr, + pptr[0])) { /* * Notify the real server: there is no * existing entry if it is not RST diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c index ef48cc55f775..182d95807bd5 100644 --- a/net/netfilter/ipvs/ip_vs_ctl.c +++ b/net/netfilter/ipvs/ip_vs_ctl.c @@ -508,17 +508,13 @@ static inline unsigned int ip_vs_rs_hashkey(int af, & IP_VS_RTAB_MASK; } -/* - * Hashes ip_vs_dest in rs_table by . - * should be called with locked tables. - */ -static int ip_vs_rs_hash(struct netns_ipvs *ipvs, struct ip_vs_dest *dest) +/* Hash ip_vs_dest in rs_table by . */ +static void ip_vs_rs_hash(struct netns_ipvs *ipvs, struct ip_vs_dest *dest) { unsigned int hash; - if (!list_empty(&dest->d_list)) { - return 0; - } + if (dest->in_rs_table) + return; /* * Hash by proto,addr,port, @@ -526,60 +522,47 @@ static int ip_vs_rs_hash(struct netns_ipvs *ipvs, struct ip_vs_dest *dest) */ hash = ip_vs_rs_hashkey(dest->af, &dest->addr, dest->port); - list_add(&dest->d_list, &ipvs->rs_table[hash]); - - return 1; + hlist_add_head_rcu(&dest->d_list, &ipvs->rs_table[hash]); + dest->in_rs_table = 1; } -/* - * UNhashes ip_vs_dest from rs_table. - * should be called with locked tables. - */ -static int ip_vs_rs_unhash(struct ip_vs_dest *dest) +/* Unhash ip_vs_dest from rs_table. */ +static void ip_vs_rs_unhash(struct ip_vs_dest *dest) { /* * Remove it from the rs_table table. */ - if (!list_empty(&dest->d_list)) { - list_del_init(&dest->d_list); + if (dest->in_rs_table) { + hlist_del_rcu(&dest->d_list); + dest->in_rs_table = 0; } - - return 1; } -/* - * Lookup real service by in the real service table. - */ -struct ip_vs_dest * -ip_vs_lookup_real_service(struct net *net, int af, __u16 protocol, - const union nf_inet_addr *daddr, - __be16 dport) +/* Check if real service by is present */ +bool ip_vs_has_real_service(struct net *net, int af, __u16 protocol, + const union nf_inet_addr *daddr, __be16 dport) { struct netns_ipvs *ipvs = net_ipvs(net); unsigned int hash; struct ip_vs_dest *dest; - /* - * Check for "full" addressed entries - * Return the first found entry - */ + /* Check for "full" addressed entries */ hash = ip_vs_rs_hashkey(af, daddr, dport); - read_lock(&ipvs->rs_lock); - list_for_each_entry(dest, &ipvs->rs_table[hash], d_list) { - if ((dest->af == af) - && ip_vs_addr_equal(af, &dest->addr, daddr) - && (dest->port == dport) - && ((dest->protocol == protocol) || - dest->vfwmark)) { + rcu_read_lock(); + hlist_for_each_entry_rcu(dest, &ipvs->rs_table[hash], d_list) { + if (dest->port == dport && + dest->af == af && + ip_vs_addr_equal(af, &dest->addr, daddr) && + (dest->protocol == protocol || dest->vfwmark)) { /* HIT */ - read_unlock(&ipvs->rs_lock); - return dest; + rcu_read_unlock(); + return true; } } - read_unlock(&ipvs->rs_lock); + rcu_read_unlock(); - return NULL; + return false; } /* @@ -612,9 +595,6 @@ ip_vs_lookup_dest(struct ip_vs_service *svc, const union nf_inet_addr *daddr, * the backup synchronization daemon. It finds the * destination to be bound to the received connection * on the backup. - * - * ip_vs_lookup_real_service() looked promissing, but - * seems not working as expected. */ struct ip_vs_dest *ip_vs_find_dest(struct net *net, int af, const union nf_inet_addr *daddr, @@ -715,7 +695,7 @@ ip_vs_trash_get_dest(struct ip_vs_service *svc, const union nf_inet_addr *daddr, __ip_vs_dst_cache_reset(dest); __ip_vs_unbind_svc(dest); free_percpu(dest->stats.cpustats); - kfree(dest); + kfree_rcu(dest, rcu_head); } } @@ -742,7 +722,7 @@ static void ip_vs_trash_cleanup(struct net *net) __ip_vs_dst_cache_reset(dest); __ip_vs_unbind_svc(dest); free_percpu(dest->stats.cpustats); - kfree(dest); + kfree_rcu(dest, rcu_head); } } @@ -807,9 +787,7 @@ __ip_vs_update_dest(struct ip_vs_service *svc, struct ip_vs_dest *dest, * Put the real service in rs_table if not present. * For now only for NAT! */ - write_lock_bh(&ipvs->rs_lock); ip_vs_rs_hash(ipvs, dest); - write_unlock_bh(&ipvs->rs_lock); } atomic_set(&dest->conn_flags, conn_flags); @@ -905,7 +883,7 @@ ip_vs_new_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest, atomic_set(&dest->persistconns, 0); atomic_set(&dest->refcnt, 1); - INIT_LIST_HEAD(&dest->d_list); + INIT_HLIST_NODE(&dest->d_list); spin_lock_init(&dest->dst_lock); spin_lock_init(&dest->stats.lock); __ip_vs_update_dest(svc, dest, udest, 1); @@ -1045,9 +1023,7 @@ static void __ip_vs_del_dest(struct net *net, struct ip_vs_dest *dest) /* * Remove it from the d-linked list with the real services. */ - write_lock_bh(&ipvs->rs_lock); ip_vs_rs_unhash(dest); - write_unlock_bh(&ipvs->rs_lock); /* * Decrease the refcnt of the dest, and free the dest @@ -1067,7 +1043,7 @@ static void __ip_vs_del_dest(struct net *net, struct ip_vs_dest *dest) time, so the operation here is OK */ atomic_dec(&dest->svc->refcnt); free_percpu(dest->stats.cpustats); - kfree(dest); + kfree_rcu(dest, rcu_head); } else { IP_VS_DBG_BUF(3, "Moving dest %s:%u into trash, " "dest->refcnt=%d\n", @@ -3811,11 +3787,9 @@ int __net_init ip_vs_control_net_init(struct net *net) int idx; struct netns_ipvs *ipvs = net_ipvs(net); - rwlock_init(&ipvs->rs_lock); - /* Initialize rs_table */ for (idx = 0; idx < IP_VS_RTAB_SIZE; idx++) - INIT_LIST_HEAD(&ipvs->rs_table[idx]); + INIT_HLIST_HEAD(&ipvs->rs_table[idx]); INIT_LIST_HEAD(&ipvs->dest_trash); atomic_set(&ipvs->ftpsvc_counter, 0); @@ -3892,7 +3866,7 @@ int __init ip_vs_control_init(void) EnterFunction(2); - /* Initialize svc_table, ip_vs_svc_fwm_table, rs_table */ + /* Initialize svc_table, ip_vs_svc_fwm_table */ for (idx = 0; idx < IP_VS_SVC_TAB_SIZE; idx++) { INIT_LIST_HEAD(&ip_vs_svc_table[idx]); INIT_LIST_HEAD(&ip_vs_svc_fwm_table[idx]);