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Commit b6a2b971 authored by Vlad Buslov's avatar Vlad Buslov Committed by David S. Miller
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net: sched: act_csum: remove dependency on rtnl lock


Use tcf lock to protect csum 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 assertion that is no longer necessary.

Signed-off-by: default avatarVlad Buslov <vladbu@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2142236b
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...@@ -50,7 +50,7 @@ static int tcf_csum_init(struct net *net, struct nlattr *nla, ...@@ -50,7 +50,7 @@ static int tcf_csum_init(struct net *net, struct nlattr *nla,
struct netlink_ext_ack *extack) struct netlink_ext_ack *extack)
{ {
struct tc_action_net *tn = net_generic(net, csum_net_id); struct tc_action_net *tn = net_generic(net, csum_net_id);
struct tcf_csum_params *params_old, *params_new; struct tcf_csum_params *params_new;
struct nlattr *tb[TCA_CSUM_MAX + 1]; struct nlattr *tb[TCA_CSUM_MAX + 1];
struct tc_csum *parm; struct tc_csum *parm;
struct tcf_csum *p; struct tcf_csum *p;
...@@ -88,20 +88,22 @@ static int tcf_csum_init(struct net *net, struct nlattr *nla, ...@@ -88,20 +88,22 @@ static int tcf_csum_init(struct net *net, struct nlattr *nla,
} }
p = to_tcf_csum(*a); p = to_tcf_csum(*a);
ASSERT_RTNL();
params_new = kzalloc(sizeof(*params_new), GFP_KERNEL); params_new = kzalloc(sizeof(*params_new), GFP_KERNEL);
if (unlikely(!params_new)) { if (unlikely(!params_new)) {
tcf_idr_release(*a, bind); tcf_idr_release(*a, bind);
return -ENOMEM; return -ENOMEM;
} }
params_old = rtnl_dereference(p->params); params_new->update_flags = parm->update_flags;
spin_lock(&p->tcf_lock);
p->tcf_action = parm->action; p->tcf_action = parm->action;
params_new->update_flags = parm->update_flags; rcu_swap_protected(p->params, params_new,
rcu_assign_pointer(p->params, params_new); lockdep_is_held(&p->tcf_lock));
if (params_old) spin_unlock(&p->tcf_lock);
kfree_rcu(params_old, rcu);
if (params_new)
kfree_rcu(params_new, rcu);
if (ret == ACT_P_CREATED) if (ret == ACT_P_CREATED)
tcf_idr_insert(tn, *a); tcf_idr_insert(tn, *a);
...@@ -599,11 +601,13 @@ static int tcf_csum_dump(struct sk_buff *skb, struct tc_action *a, int bind, ...@@ -599,11 +601,13 @@ static int tcf_csum_dump(struct sk_buff *skb, struct tc_action *a, int bind,
.index = p->tcf_index, .index = p->tcf_index,
.refcnt = refcount_read(&p->tcf_refcnt) - ref, .refcnt = refcount_read(&p->tcf_refcnt) - ref,
.bindcnt = atomic_read(&p->tcf_bindcnt) - bind, .bindcnt = atomic_read(&p->tcf_bindcnt) - bind,
.action = p->tcf_action,
}; };
struct tcf_t t; struct tcf_t t;
params = rtnl_dereference(p->params); spin_lock(&p->tcf_lock);
params = rcu_dereference_protected(p->params,
lockdep_is_held(&p->tcf_lock));
opt.action = p->tcf_action;
opt.update_flags = params->update_flags; opt.update_flags = params->update_flags;
if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt)) if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
...@@ -612,10 +616,12 @@ static int tcf_csum_dump(struct sk_buff *skb, struct tc_action *a, int bind, ...@@ -612,10 +616,12 @@ static int tcf_csum_dump(struct sk_buff *skb, struct tc_action *a, int bind,
tcf_tm_dump(&t, &p->tcf_tm); tcf_tm_dump(&t, &p->tcf_tm);
if (nla_put_64bit(skb, TCA_CSUM_TM, sizeof(t), &t, TCA_CSUM_PAD)) if (nla_put_64bit(skb, TCA_CSUM_TM, sizeof(t), &t, TCA_CSUM_PAD))
goto nla_put_failure; goto nla_put_failure;
spin_unlock(&p->tcf_lock);
return skb->len; return skb->len;
nla_put_failure: nla_put_failure:
spin_unlock(&p->tcf_lock);
nlmsg_trim(skb, b); nlmsg_trim(skb, b);
return -1; return -1;
} }
......
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