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Message-ID: <20230815173031.168344-4-ja@ssi.bg>
Date: Tue, 15 Aug 2023 20:30:20 +0300
From: Julian Anastasov <ja@....bg>
To: Simon Horman <horms@...ge.net.au>
Cc: lvs-devel@...r.kernel.org, netfilter-devel@...r.kernel.org,
netdev@...r.kernel.org, "Paul E . McKenney" <paulmck@...nel.org>,
rcu@...r.kernel.org, Dust Li <dust.li@...ux.alibaba.com>,
Jiejian Wu <jiejian@...ux.alibaba.com>,
Jiri Wiesner <jwiesner@...e.de>
Subject: [PATCH RFC net-next 03/14] ipvs: some service readers can use RCU
Some places walk the services under mutex but they can just use RCU:
* ip_vs_dst_event() uses ip_vs_forget_dev() which uses its own lock
to modify dest
* ip_vs_genl_dump_services(): ip_vs_genl_fill_service() just fills skb
* ip_vs_genl_parse_service(): move RCU lock to callers
ip_vs_genl_set_cmd(), ip_vs_genl_dump_dests() and ip_vs_genl_get_cmd()
* ip_vs_genl_dump_dests(): just fill skb
Signed-off-by: Julian Anastasov <ja@....bg>
---
net/netfilter/ipvs/ip_vs_ctl.c | 47 +++++++++++++++++-----------------
1 file changed, 23 insertions(+), 24 deletions(-)
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index e5ae4fac8ec9..276fdc31e938 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -1758,23 +1758,21 @@ static int ip_vs_dst_event(struct notifier_block *this, unsigned long event,
if (event != NETDEV_DOWN || !ipvs)
return NOTIFY_DONE;
IP_VS_DBG(3, "%s() dev=%s\n", __func__, dev->name);
- mutex_lock(&ipvs->service_mutex);
+ rcu_read_lock();
for (idx = 0; idx < IP_VS_SVC_TAB_SIZE; idx++) {
- hlist_for_each_entry(svc, &ipvs->svc_table[idx], s_list) {
- list_for_each_entry(dest, &svc->destinations,
- n_list) {
+ hlist_for_each_entry_rcu(svc, &ipvs->svc_table[idx], s_list)
+ list_for_each_entry_rcu(dest, &svc->destinations,
+ n_list)
ip_vs_forget_dev(dest, dev);
- }
- }
- hlist_for_each_entry(svc, &ipvs->svc_fwm_table[idx], f_list) {
- list_for_each_entry(dest, &svc->destinations,
- n_list) {
+ hlist_for_each_entry_rcu(svc, &ipvs->svc_fwm_table[idx], f_list)
+ list_for_each_entry_rcu(dest, &svc->destinations,
+ n_list)
ip_vs_forget_dev(dest, dev);
- }
- }
}
+ rcu_read_unlock();
+ mutex_lock(&ipvs->service_mutex);
spin_lock_bh(&ipvs->dest_trash_lock);
list_for_each_entry(dest, &ipvs->dest_trash, t_list) {
ip_vs_forget_dev(dest, dev);
@@ -3314,9 +3312,9 @@ static int ip_vs_genl_fill_service(struct sk_buff *skb,
goto nla_put_failure;
}
- sched = rcu_dereference_protected(svc->scheduler, 1);
+ sched = rcu_dereference(svc->scheduler);
sched_name = sched ? sched->name : "none";
- pe = rcu_dereference_protected(svc->pe, 1);
+ pe = rcu_dereference(svc->pe);
if (nla_put_string(skb, IPVS_SVC_ATTR_SCHED_NAME, sched_name) ||
(pe && nla_put_string(skb, IPVS_SVC_ATTR_PE_NAME, pe->name)) ||
nla_put(skb, IPVS_SVC_ATTR_FLAGS, sizeof(flags), &flags) ||
@@ -3370,9 +3368,9 @@ static int ip_vs_genl_dump_services(struct sk_buff *skb,
struct net *net = sock_net(skb->sk);
struct netns_ipvs *ipvs = net_ipvs(net);
- mutex_lock(&ipvs->service_mutex);
+ rcu_read_lock();
for (i = 0; i < IP_VS_SVC_TAB_SIZE; i++) {
- hlist_for_each_entry(svc, &ipvs->svc_table[i], s_list) {
+ hlist_for_each_entry_rcu(svc, &ipvs->svc_table[i], s_list) {
if (++idx <= start)
continue;
if (ip_vs_genl_dump_service(skb, svc, cb) < 0) {
@@ -3383,7 +3381,7 @@ static int ip_vs_genl_dump_services(struct sk_buff *skb,
}
for (i = 0; i < IP_VS_SVC_TAB_SIZE; i++) {
- hlist_for_each_entry(svc, &ipvs->svc_fwm_table[i], f_list) {
+ hlist_for_each_entry_rcu(svc, &ipvs->svc_fwm_table[i], f_list) {
if (++idx <= start)
continue;
if (ip_vs_genl_dump_service(skb, svc, cb) < 0) {
@@ -3394,7 +3392,7 @@ static int ip_vs_genl_dump_services(struct sk_buff *skb,
}
nla_put_failure:
- mutex_unlock(&ipvs->service_mutex);
+ rcu_read_unlock();
cb->args[0] = idx;
return skb->len;
@@ -3450,13 +3448,11 @@ static int ip_vs_genl_parse_service(struct netns_ipvs *ipvs,
usvc->fwmark = 0;
}
- rcu_read_lock();
if (usvc->fwmark)
svc = __ip_vs_svc_fwm_find(ipvs, usvc->af, usvc->fwmark);
else
svc = __ip_vs_service_find(ipvs, usvc->af, usvc->protocol,
&usvc->addr, usvc->port);
- rcu_read_unlock();
*ret_svc = svc;
/* If a full entry was requested, check for the additional fields */
@@ -3583,7 +3579,7 @@ static int ip_vs_genl_dump_dests(struct sk_buff *skb,
struct net *net = sock_net(skb->sk);
struct netns_ipvs *ipvs = net_ipvs(net);
- mutex_lock(&ipvs->service_mutex);
+ rcu_read_lock();
/* Try to find the service for which to dump destinations */
if (nlmsg_parse_deprecated(cb->nlh, GENL_HDRLEN, attrs, IPVS_CMD_ATTR_MAX, ip_vs_cmd_policy, cb->extack))
@@ -3595,7 +3591,7 @@ static int ip_vs_genl_dump_dests(struct sk_buff *skb,
goto out_err;
/* Dump the destinations */
- list_for_each_entry(dest, &svc->destinations, n_list) {
+ list_for_each_entry_rcu(dest, &svc->destinations, n_list) {
if (++idx <= start)
continue;
if (ip_vs_genl_dump_dest(skb, dest, cb) < 0) {
@@ -3608,7 +3604,7 @@ static int ip_vs_genl_dump_dests(struct sk_buff *skb,
cb->args[0] = idx;
out_err:
- mutex_unlock(&ipvs->service_mutex);
+ rcu_read_unlock();
return skb->len;
}
@@ -3914,9 +3910,12 @@ static int ip_vs_genl_set_cmd(struct sk_buff *skb, struct genl_info *info)
if (cmd == IPVS_CMD_NEW_SERVICE || cmd == IPVS_CMD_SET_SERVICE)
need_full_svc = true;
+ /* We use function that requires RCU lock */
+ rcu_read_lock();
ret = ip_vs_genl_parse_service(ipvs, &usvc,
info->attrs[IPVS_CMD_ATTR_SERVICE],
need_full_svc, &svc);
+ rcu_read_unlock();
if (ret)
goto out;
@@ -4036,7 +4035,7 @@ static int ip_vs_genl_get_cmd(struct sk_buff *skb, struct genl_info *info)
if (!msg)
return -ENOMEM;
- mutex_lock(&ipvs->service_mutex);
+ rcu_read_lock();
reply = genlmsg_put_reply(msg, info, &ip_vs_genl_family, 0, reply_cmd);
if (reply == NULL)
@@ -4104,7 +4103,7 @@ static int ip_vs_genl_get_cmd(struct sk_buff *skb, struct genl_info *info)
out_err:
nlmsg_free(msg);
out:
- mutex_unlock(&ipvs->service_mutex);
+ rcu_read_unlock();
return ret;
}
--
2.41.0
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