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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 <ja@xxxxxx>
---
include/net/ip_vs.h | 2 +-
net/netfilter/ipvs/ip_vs_conn.c | 8 +++++---
net/netfilter/ipvs/ip_vs_ctl.c | 32 +++++++++++++++++---------------
net/netfilter/ipvs/ip_vs_sync.c | 11 ++++-------
4 files changed, 27 insertions(+), 26 deletions(-)
diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index 034ce38..40bb2a6 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -1434,7 +1434,7 @@ extern struct ip_vs_dest *
ip_vs_find_dest(struct net *net, int af, const union nf_inet_addr *daddr,
__be16 dport, const union nf_inet_addr *vaddr, __be16 vport,
__u16 protocol, __u32 fwmark, __u32 flags);
-extern struct ip_vs_dest *ip_vs_try_bind_dest(struct ip_vs_conn *cp);
+extern void ip_vs_try_bind_dest(struct ip_vs_conn *cp);
static inline void ip_vs_dest_hold(struct ip_vs_dest *dest)
{
diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c
index 1b29e4a..54de340 100644
--- a/net/netfilter/ipvs/ip_vs_conn.c
+++ b/net/netfilter/ipvs/ip_vs_conn.c
@@ -611,10 +611,11 @@ ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest
*dest)
* Check if there is a destination for the connection, if so
* bind the connection to the destination.
*/
-struct ip_vs_dest *ip_vs_try_bind_dest(struct ip_vs_conn *cp)
+void ip_vs_try_bind_dest(struct ip_vs_conn *cp)
{
struct ip_vs_dest *dest;
+ rcu_read_lock();
dest = ip_vs_find_dest(ip_vs_conn_net(cp), cp->af, &cp->daddr,
cp->dport, &cp->vaddr, cp->vport,
cp->protocol, cp->fwmark, cp->flags);
@@ -624,7 +625,8 @@ struct ip_vs_dest *ip_vs_try_bind_dest(struct ip_vs_conn
*cp)
spin_lock(&cp->lock);
if (cp->dest) {
spin_unlock(&cp->lock);
- return dest;
+ rcu_read_unlock();
+ return;
}
/* Applications work depending on the forwarding method
@@ -648,7 +650,7 @@ struct ip_vs_dest *ip_vs_try_bind_dest(struct ip_vs_conn
*cp)
if (pd && atomic_read(&pd->appcnt))
ip_vs_bind_app(cp, pd->pp);
}
- return dest;
+ rcu_read_unlock();
}
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index ada61a8..8778927 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -563,8 +563,8 @@ 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,
@@ -575,7 +575,7 @@ 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)) {
@@ -589,10 +589,11 @@ 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,
@@ -613,8 +614,6 @@ 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;
}
@@ -824,7 +823,7 @@ __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);
@@ -931,10 +930,10 @@ 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__);
@@ -995,10 +994,10 @@ 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__);
@@ -1067,7 +1066,7 @@ 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)
@@ -1092,7 +1091,10 @@ 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__);
@@ -2102,7 +2104,7 @@ 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,
diff --git a/net/netfilter/ipvs/ip_vs_sync.c b/net/netfilter/ipvs/ip_vs_sync.c
index 6cc3e52..9724174 100644
--- a/net/netfilter/ipvs/ip_vs_sync.c
+++ b/net/netfilter/ipvs/ip_vs_sync.c
@@ -858,23 +858,20 @@ static void ip_vs_proc_conn(struct net *net, struct
ip_vs_conn_param *param,
flags |= cp->flags & ~IP_VS_CONN_F_BACKUP_UPD_MASK;
cp->flags = flags;
spin_unlock(&cp->lock);
- if (!dest) {
- dest = ip_vs_try_bind_dest(cp);
- if (dest)
- ip_vs_dest_put(dest);
- }
+ if (!dest)
+ ip_vs_try_bind_dest(cp);
} else {
/*
* Find the appropriate destination for the connection.
* If it is not found the connection will remain unbound
* but still handled.
*/
+ rcu_read_lock();
dest = ip_vs_find_dest(net, type, daddr, dport, param->vaddr,
param->vport, protocol, fwmark, flags);
cp = ip_vs_conn_new(param, daddr, dport, flags, dest, fwmark);
- if (dest)
- ip_vs_dest_put(dest);
+ rcu_read_unlock();
if (!cp) {
if (param->pe_data)
kfree(param->pe_data);
--
1.7.3.4
--
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