From 413c2d04e9494ca38629d8a7ffeff1e4398a9fe3 Mon Sep 17 00:00:00 2001 From: Julian Anastasov Date: Fri, 22 Mar 2013 11:46:52 +0200 Subject: ipvs: convert dests to rcu In previous commits the schedulers started to access svc->destinations with _rcu list traversal primitives because the IP_VS_WAIT_WHILE macro still plays the role of grace period. Now it is time to finish the updating part, i.e. adding and deleting of dests with _rcu suffix before removing the IP_VS_WAIT_WHILE in next commit. We use the same rule for conns as for the schedulers: dests can be searched in RCU read-side critical section where ip_vs_dest_hold can be called by ip_vs_bind_dest. Some things are not perfect, for example, calling functions like ip_vs_lookup_dest from updating code under RCU, just because we use some function both from reader and from updater. Signed-off-by: Julian Anastasov Signed-off-by: Simon Horman --- net/netfilter/ipvs/ip_vs_ctl.c | 32 +++++++++++++++++--------------- 1 file changed, 17 insertions(+), 15 deletions(-) (limited to 'net/netfilter/ipvs/ip_vs_ctl.c') diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c index 2bfd807bc93f..0763cc6e092b 100644 --- a/net/netfilter/ipvs/ip_vs_ctl.c +++ b/net/netfilter/ipvs/ip_vs_ctl.c @@ -565,8 +565,8 @@ bool ip_vs_has_real_service(struct net *net, int af, __u16 protocol, return false; } -/* - * Lookup destination by {addr,port} in the given service +/* Lookup destination by {addr,port} in the given service + * Called under RCU lock. */ static struct ip_vs_dest * ip_vs_lookup_dest(struct ip_vs_service *svc, const union nf_inet_addr *daddr, @@ -577,7 +577,7 @@ ip_vs_lookup_dest(struct ip_vs_service *svc, const union nf_inet_addr *daddr, /* * Find the destination for the given service */ - list_for_each_entry(dest, &svc->destinations, n_list) { + list_for_each_entry_rcu(dest, &svc->destinations, n_list) { if ((dest->af == svc->af) && ip_vs_addr_equal(svc->af, &dest->addr, daddr) && (dest->port == dport)) { @@ -591,10 +591,11 @@ ip_vs_lookup_dest(struct ip_vs_service *svc, const union nf_inet_addr *daddr, /* * Find destination by {daddr,dport,vaddr,protocol} - * Cretaed to be used in ip_vs_process_message() in + * Created to be used in ip_vs_process_message() in * the backup synchronization daemon. It finds the * destination to be bound to the received connection * on the backup. + * Called under RCU lock, no refcnt is returned. */ struct ip_vs_dest *ip_vs_find_dest(struct net *net, int af, const union nf_inet_addr *daddr, @@ -615,8 +616,6 @@ struct ip_vs_dest *ip_vs_find_dest(struct net *net, int af, dest = ip_vs_lookup_dest(svc, daddr, port); if (!dest) dest = ip_vs_lookup_dest(svc, daddr, port ^ dport); - if (dest) - ip_vs_dest_hold(dest); ip_vs_service_put(svc); return dest; } @@ -826,7 +825,7 @@ __ip_vs_update_dest(struct ip_vs_service *svc, struct ip_vs_dest *dest, IP_VS_WAIT_WHILE(atomic_read(&svc->usecnt) > 0); if (add) { - list_add(&dest->n_list, &svc->destinations); + list_add_rcu(&dest->n_list, &svc->destinations); svc->num_dests++; if (svc->scheduler->add_dest) svc->scheduler->add_dest(svc, dest); @@ -933,10 +932,10 @@ ip_vs_add_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest) ip_vs_addr_copy(svc->af, &daddr, &udest->addr); - /* - * Check if the dest already exists in the list - */ + /* We use function that requires RCU lock */ + rcu_read_lock(); dest = ip_vs_lookup_dest(svc, &daddr, dport); + rcu_read_unlock(); if (dest != NULL) { IP_VS_DBG(1, "%s(): dest already exists\n", __func__); @@ -997,10 +996,10 @@ ip_vs_edit_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest) ip_vs_addr_copy(svc->af, &daddr, &udest->addr); - /* - * Lookup the destination list - */ + /* We use function that requires RCU lock */ + rcu_read_lock(); dest = ip_vs_lookup_dest(svc, &daddr, dport); + rcu_read_unlock(); if (dest == NULL) { IP_VS_DBG(1, "%s(): dest doesn't exist\n", __func__); @@ -1069,7 +1068,7 @@ static void __ip_vs_unlink_dest(struct ip_vs_service *svc, /* * Remove it from the d-linked destination list. */ - list_del(&dest->n_list); + list_del_rcu(&dest->n_list); svc->num_dests--; if (svcupd && svc->scheduler->del_dest) @@ -1094,7 +1093,10 @@ ip_vs_del_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest) EnterFunction(2); + /* We use function that requires RCU lock */ + rcu_read_lock(); dest = ip_vs_lookup_dest(svc, &udest->addr, dport); + rcu_read_unlock(); if (dest == NULL) { IP_VS_DBG(1, "%s(): destination not found!\n", __func__); @@ -2104,7 +2106,7 @@ static int ip_vs_info_seq_show(struct seq_file *seq, void *v) else seq_putc(seq, '\n'); - list_for_each_entry(dest, &svc->destinations, n_list) { + list_for_each_entry_rcu(dest, &svc->destinations, n_list) { #ifdef CONFIG_IP_VS_IPV6 if (dest->af == AF_INET6) seq_printf(seq, -- cgit v1.2.3-55-g7522