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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 <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vlad Buslov 2018-08-10 20:51:50 +03:00 committed by David S. Miller
parent c8814552fe
commit 729e012609
1 changed files with 13 additions and 13 deletions
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26
net/sched/act_tunnel_key.c
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@ -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;
}