From 729e01260989cc06c8a78491b46545793aef323a Mon Sep 17 00:00:00 2001 From: Vlad Buslov Date: Fri, 10 Aug 2018 20:51:50 +0300 Subject: [PATCH] net: sched: act_tunnel_key: remove dependency on rtnl lock Use tcf lock to protect tunnel key action struct private data from concurrent modification in init and dump. Use rcu swap operation to reassign params pointer under protection of tcf lock. (old params value is not used by init, so there is no need of standalone rcu dereference step) Remove rtnl lock assertion that is no longer required. Signed-off-by: Vlad Buslov Signed-off-by: David S. Miller --- net/sched/act_tunnel_key.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) diff --git a/net/sched/act_tunnel_key.c b/net/sched/act_tunnel_key.c index d42d9e112789..ba2ae9f75ef5 100644 --- a/net/sched/act_tunnel_key.c +++ b/net/sched/act_tunnel_key.c @@ -204,7 +204,6 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla, { struct tc_action_net *tn = net_generic(net, tunnel_key_net_id); struct nlattr *tb[TCA_TUNNEL_KEY_MAX + 1]; - struct tcf_tunnel_key_params *params_old; struct tcf_tunnel_key_params *params_new; struct metadata_dst *metadata = NULL; struct tc_tunnel_key *parm; @@ -346,24 +345,22 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla, t = to_tunnel_key(*a); - ASSERT_RTNL(); params_new = kzalloc(sizeof(*params_new), GFP_KERNEL); if (unlikely(!params_new)) { tcf_idr_release(*a, bind); NL_SET_ERR_MSG(extack, "Cannot allocate tunnel key parameters"); return -ENOMEM; } - - params_old = rtnl_dereference(t->params); - - t->tcf_action = parm->action; params_new->tcft_action = parm->t_action; params_new->tcft_enc_metadata = metadata; - rcu_assign_pointer(t->params, params_new); - - if (params_old) - kfree_rcu(params_old, rcu); + spin_lock(&t->tcf_lock); + t->tcf_action = parm->action; + rcu_swap_protected(t->params, params_new, + lockdep_is_held(&t->tcf_lock)); + spin_unlock(&t->tcf_lock); + if (params_new) + kfree_rcu(params_new, rcu); if (ret == ACT_P_CREATED) tcf_idr_insert(tn, *a); @@ -485,12 +482,13 @@ static int tunnel_key_dump(struct sk_buff *skb, struct tc_action *a, .index = t->tcf_index, .refcnt = refcount_read(&t->tcf_refcnt) - ref, .bindcnt = atomic_read(&t->tcf_bindcnt) - bind, - .action = t->tcf_action, }; struct tcf_t tm; - params = rtnl_dereference(t->params); - + spin_lock(&t->tcf_lock); + params = rcu_dereference_protected(t->params, + lockdep_is_held(&t->tcf_lock)); + opt.action = t->tcf_action; opt.t_action = params->tcft_action; if (nla_put(skb, TCA_TUNNEL_KEY_PARMS, sizeof(opt), &opt)) @@ -522,10 +520,12 @@ static int tunnel_key_dump(struct sk_buff *skb, struct tc_action *a, if (nla_put_64bit(skb, TCA_TUNNEL_KEY_TM, sizeof(tm), &tm, TCA_TUNNEL_KEY_PAD)) goto nla_put_failure; + spin_unlock(&t->tcf_lock); return skb->len; nla_put_failure: + spin_unlock(&t->tcf_lock); nlmsg_trim(skb, b); return -1; }