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Commit c8814552 authored by Vlad Buslov's avatar Vlad Buslov Committed by David S. Miller
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net: sched: act_skbmod: remove dependency on rtnl lock 



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: default avatarVlad Buslov <vladbu@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 5e48180e

net/sched/act_skbmod.c

+9 −5
Original line number Diff line number Diff line
@@ -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;

}