Commit 3de0ec28 authored by Julian Anastasov's avatar Julian Anastasov Committed by Jakub Kicinski
Browse files

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: default avatarJulian Anastasov <ja@ssi.bg>
Reviewed-by: default avatarDust Li <dust.li@linux.alibaba.com>
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Link: https://patch.msgid.link/20260224205048.4718-3-fw@strlen.de


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 74455a5b

net/netfilter/ipvs/ip_vs_ctl.c

+23 −24
Original line number Diff line number Diff line
@@ -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);
@@ -3317,9 +3315,9 @@ 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) ||
@@ -3373,9 +3371,9 @@ 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) {
@@ -3386,7 +3384,7 @@ 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) {
@@ -3397,7 +3395,7 @@ 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;
@@ -3453,13 +3451,11 @@ 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 */
@@ -3586,7 +3582,7 @@ 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))
@@ -3598,7 +3594,7 @@ 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) {
@@ -3611,7 +3607,7 @@ 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 (hlist_bl) */

	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;

}