From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vlad Buslov Subject: [PATCH net-next 09/14] net: sched: act_skbmod: remove dependency on rtnl lock Date: Mon, 6 Aug 2018 09:54:20 +0300 Message-ID: <1533538465-23199-10-git-send-email-vladbu@mellanox.com> References: <1533538465-23199-1-git-send-email-vladbu@mellanox.com> Cc: davem@davemloft.net, jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us, pablo@netfilter.org, kadlec@blackhole.kfki.hu, fw@strlen.de, ast@kernel.org, daniel@iogearbox.net, edumazet@google.com, keescook@chromium.org, marcelo.leitner@gmail.com, Vlad Buslov To: netdev@vger.kernel.org Return-path: Received: from mail-il-dmz.mellanox.com ([193.47.165.129]:56357 "EHLO mellanox.co.il" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726521AbeHFJCd (ORCPT ); Mon, 6 Aug 2018 05:02:33 -0400 In-Reply-To: <1533538465-23199-1-git-send-email-vladbu@mellanox.com> Sender: netdev-owner@vger.kernel.org List-ID: Move read of skbmod_p rcu pointer to be protected by tcf spinlock. Use tcf spinlock to protect private skbmod data from concurrent modification during dump. Signed-off-by: Vlad Buslov --- net/sched/act_skbmod.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/net/sched/act_skbmod.c b/net/sched/act_skbmod.c index c437c6d51a71..e9c86ade3b40 100644 --- a/net/sched/act_skbmod.c +++ b/net/sched/act_skbmod.c @@ -156,7 +156,6 @@ static int tcf_skbmod_init(struct net *net, struct nlattr *nla, d = to_skbmod(*a); - ASSERT_RTNL(); p = kzalloc(sizeof(struct tcf_skbmod_params), GFP_KERNEL); if (unlikely(!p)) { tcf_idr_release(*a, bind); @@ -166,10 +165,10 @@ static int tcf_skbmod_init(struct net *net, struct nlattr *nla, p->flags = lflags; d->tcf_action = parm->action; - p_old = rtnl_dereference(d->skbmod_p); - if (ovr) spin_lock_bh(&d->tcf_lock); + /* Protected by tcf_lock if overwriting existing action. */ + p_old = rcu_dereference_protected(d->skbmod_p, 1); if (lflags & SKBMOD_F_DMAC) ether_addr_copy(p->eth_dst, daddr); @@ -205,15 +204,18 @@ static int tcf_skbmod_dump(struct sk_buff *skb, struct tc_action *a, { struct tcf_skbmod *d = to_skbmod(a); unsigned char *b = skb_tail_pointer(skb); - struct tcf_skbmod_params *p = rtnl_dereference(d->skbmod_p); + struct tcf_skbmod_params *p; struct tc_skbmod opt = { .index = d->tcf_index, .refcnt = refcount_read(&d->tcf_refcnt) - ref, .bindcnt = atomic_read(&d->tcf_bindcnt) - bind, - .action = d->tcf_action, }; struct tcf_t t; + spin_lock_bh(&d->tcf_lock); + opt.action = d->tcf_action; + p = rcu_dereference_protected(d->skbmod_p, + lockdep_is_held(&d->tcf_lock)); opt.flags = p->flags; if (nla_put(skb, TCA_SKBMOD_PARMS, sizeof(opt), &opt)) goto nla_put_failure; @@ -231,8 +233,10 @@ static int tcf_skbmod_dump(struct sk_buff *skb, struct tc_action *a, if (nla_put_64bit(skb, TCA_SKBMOD_TM, sizeof(t), &t, TCA_SKBMOD_PAD)) goto nla_put_failure; + spin_unlock_bh(&d->tcf_lock); return skb->len; nla_put_failure: + spin_unlock_bh(&d->tcf_lock); nlmsg_trim(skb, b); return -1; } -- 2.7.5