From: Dust Li <dust.li@linux.alibaba.com>
To: Julian Anastasov <ja@ssi.bg>, Simon Horman <horms@verge.net.au>
Cc: lvs-devel@vger.kernel.org, netfilter-devel@vger.kernel.org,
Jiejian Wu <jiejian@linux.alibaba.com>,
rcu@vger.kernel.org
Subject: Re: [PATCHv6 net-next 03/14] ipvs: some service readers can use RCU
Date: Fri, 24 Oct 2025 10:21:14 +0800 [thread overview]
Message-ID: <aPrimkqc9leCCZQf@linux.alibaba.com> (raw)
In-Reply-To: <20251019155711.67609-4-ja@ssi.bg>
On 2025-10-19 18:57:00, Julian Anastasov wrote:
>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@ssi.bg>
Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
Best regards,
Dust
>---
> 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 2fb9034b4f53..b18d08d79bcb 100644
>--- a/net/netfilter/ipvs/ip_vs_ctl.c
>+++ b/net/netfilter/ipvs/ip_vs_ctl.c
>@@ -1759,23 +1759,21 @@ 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);
>@@ -3318,9 +3316,9 @@ 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) ||
>@@ -3374,9 +3372,9 @@ 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) {
>@@ -3387,7 +3385,7 @@ 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) {
>@@ -3398,7 +3396,7 @@ 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;
>@@ -3454,13 +3452,11 @@ 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 */
>@@ -3587,7 +3583,7 @@ 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))
>@@ -3599,7 +3595,7 @@ 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) {
>@@ -3612,7 +3608,7 @@ 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;
> }
>@@ -3915,9 +3911,12 @@ 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;
>
>@@ -4037,7 +4036,7 @@ 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)
>@@ -4105,7 +4104,7 @@ 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;
> }
>--
>2.51.0
>
next prev parent reply other threads:[~2025-10-24 2:21 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-19 15:56 [PATCHv6 net-next 00/14] ipvs: per-net tables and optimizations Julian Anastasov
2025-10-19 15:56 ` [PATCHv6 net-next 01/14] rculist_bl: add hlist_bl_for_each_entry_continue_rcu Julian Anastasov
2025-10-23 11:44 ` Florian Westphal
2025-10-23 13:33 ` Julian Anastasov
2025-10-19 15:56 ` [PATCHv6 net-next 02/14] ipvs: make ip_vs_svc_table and ip_vs_svc_fwm_table per netns Julian Anastasov
2025-10-19 15:57 ` [PATCHv6 net-next 03/14] ipvs: some service readers can use RCU Julian Anastasov
2025-10-24 2:21 ` Dust Li [this message]
2025-10-19 15:57 ` [PATCHv6 net-next 04/14] ipvs: use single svc table Julian Anastasov
2025-10-19 15:57 ` [PATCHv6 net-next 05/14] ipvs: do not keep dest_dst after dest is removed Julian Anastasov
2025-10-19 15:57 ` [PATCHv6 net-next 06/14] ipvs: use more counters to avoid service lookups Julian Anastasov
2025-10-19 15:57 ` [PATCHv6 net-next 07/14] ipvs: add resizable hash tables Julian Anastasov
2025-10-19 15:57 ` [PATCHv6 net-next 08/14] ipvs: use resizable hash table for services Julian Anastasov
2025-10-19 15:57 ` [PATCHv6 net-next 09/14] ipvs: switch to per-net connection table Julian Anastasov
2025-10-19 15:57 ` [PATCHv6 net-next 10/14] ipvs: show the current conn_tab size to users Julian Anastasov
2025-10-19 15:57 ` [PATCHv6 net-next 11/14] ipvs: no_cport and dropentry counters can be per-net Julian Anastasov
2025-10-19 15:57 ` [PATCHv6 net-next 12/14] ipvs: use more keys for connection hashing Julian Anastasov
2025-10-19 15:57 ` [PATCHv6 net-next 13/14] ipvs: add ip_vs_status info Julian Anastasov
2025-10-19 15:57 ` [PATCHv6 net-next 14/14] ipvs: add conn_lfactor and svc_lfactor sysctl vars Julian Anastasov
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