From bb2d3335f171d91967c006f60d37faabfbb09ff6 Mon Sep 17 00:00:00 2001 From: Geliang Tang Date: Tue, 2 Feb 2021 06:18:04 +0000 Subject: [PATCH] mptcp: use WRITE_ONCE/READ_ONCE for the pernet *_max This patch uses WRITE_ONCE() and READ_ONCE for all the pernet add_addr_signal_max, add_addr_accept_max, local_addr_max and subflows_max fields in struct pm_nl_pernet to avoid concurrency issues. Reviewed-by: Mat Martineau Signed-off-by: Geliang Tang --- net/mptcp/pm_netlink.c | 36 +++++++++++++++++++++++------------- 1 file changed, 23 insertions(+), 13 deletions(-) diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index 83976b9ee99bc..7d6081d9a1db8 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -572,6 +572,7 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet, struct mptcp_pm_addr_entry *entry) { struct mptcp_pm_addr_entry *cur; + unsigned int addr_max; int ret = -EINVAL; spin_lock_bh(&pernet->lock); @@ -614,10 +615,14 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet, if (entry->addr.id > pernet->next_id) pernet->next_id = entry->addr.id; - if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL) - pernet->add_addr_signal_max++; - if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) - pernet->local_addr_max++; + if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL) { + addr_max = READ_ONCE(pernet->add_addr_signal_max); + WRITE_ONCE(pernet->add_addr_signal_max, addr_max + 1); + } + if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) { + addr_max = READ_ONCE(pernet->local_addr_max); + WRITE_ONCE(pernet->local_addr_max, addr_max + 1); + } pernet->addrs++; list_add_tail_rcu(&entry->list, &pernet->local_addr_list); @@ -912,6 +917,7 @@ static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info) struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR]; struct pm_nl_pernet *pernet = genl_info_pm_nl(info); struct mptcp_pm_addr_entry addr, *entry; + unsigned int addr_max; int ret; ret = mptcp_pm_parse_addr(attr, info, false, &addr); @@ -925,10 +931,14 @@ static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info) spin_unlock_bh(&pernet->lock); return -EINVAL; } - if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL) - pernet->add_addr_signal_max--; - if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) - pernet->local_addr_max--; + if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL) { + addr_max = READ_ONCE(pernet->add_addr_signal_max); + WRITE_ONCE(pernet->add_addr_signal_max, addr_max - 1); + } + if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) { + addr_max = READ_ONCE(pernet->local_addr_max); + WRITE_ONCE(pernet->local_addr_max, addr_max - 1); + } pernet->addrs--; list_del_rcu(&entry->list); @@ -956,9 +966,9 @@ static void __flush_addrs(struct net *net, struct list_head *list) static void __reset_counters(struct pm_nl_pernet *pernet) { - pernet->add_addr_signal_max = 0; - pernet->add_addr_accept_max = 0; - pernet->local_addr_max = 0; + WRITE_ONCE(pernet->add_addr_signal_max, 0); + WRITE_ONCE(pernet->add_addr_accept_max, 0); + WRITE_ONCE(pernet->local_addr_max, 0); pernet->addrs = 0; } @@ -1130,12 +1140,12 @@ mptcp_nl_cmd_set_limits(struct sk_buff *skb, struct genl_info *info) int ret; spin_lock_bh(&pernet->lock); - rcv_addrs = pernet->add_addr_accept_max; + rcv_addrs = READ_ONCE(pernet->add_addr_accept_max); ret = parse_limit(info, MPTCP_PM_ATTR_RCV_ADD_ADDRS, &rcv_addrs); if (ret) goto unlock; - subflows = pernet->subflows_max; + subflows = READ_ONCE(pernet->subflows_max); ret = parse_limit(info, MPTCP_PM_ATTR_SUBFLOWS, &subflows); if (ret) goto unlock;