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Commit eec94fdb authored by Vlad Buslov's avatar Vlad Buslov Committed by David S. Miller
Browse files

net: sched: use rcu for action cookie update 



Implement functions to atomically update and free action cookie
using rcu mechanism.

Reviewed-by: default avatarMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: default avatarVlad Buslov <vladbu@mellanox.com>
Signed-off-by: default avatarJiri Pirko <jiri@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b2335040

include/net/act_api.h

+1 −1
Original line number Diff line number Diff line
@@ -37,7 +37,7 @@ struct tc_action { 
	spinlock_t			tcfa_lock;

	struct gnet_stats_basic_cpu __percpu *cpu_bstats;

	struct gnet_stats_queue __percpu *cpu_qstats;

	struct tc_cookie	*act_cookie;

	struct tc_cookie	__rcu *act_cookie;

	struct tcf_chain	*goto_chain;

};

#define tcf_index	common.tcfa_index

include/net/pkt_cls.h

+1 −0
Original line number Diff line number Diff line
@@ -781,6 +781,7 @@ struct tc_mqprio_qopt_offload { 
struct tc_cookie {

	u8  *data;

	u32 len;

	struct rcu_head rcu;

};



struct tc_qopt_offload_stats {

net/sched/act_api.c

+30 −14
Original line number Diff line number Diff line
@@ -55,6 +55,24 @@ static void tcf_action_goto_chain_exec(const struct tc_action *a, 
	res->goto_tp = rcu_dereference_bh(chain->filter_chain);

}



static void tcf_free_cookie_rcu(struct rcu_head *p)

{

	struct tc_cookie *cookie = container_of(p, struct tc_cookie, rcu);



	kfree(cookie->data);

	kfree(cookie);

}



static void tcf_set_action_cookie(struct tc_cookie __rcu **old_cookie,

				  struct tc_cookie *new_cookie)

{

	struct tc_cookie *old;



	old = xchg(old_cookie, new_cookie);

	if (old)

		call_rcu(&old->rcu, tcf_free_cookie_rcu);

}



/* XXX: For standalone actions, we don't need a RCU grace period either, because

 * actions are always connected to filters and filters are already destroyed in

 * RCU callbacks, so after a RCU grace period actions are already disconnected
@@ -65,10 +83,7 @@ static void free_tcf(struct tc_action *p) 
	free_percpu(p->cpu_bstats);

	free_percpu(p->cpu_qstats);



	if (p->act_cookie) {

		kfree(p->act_cookie->data);

		kfree(p->act_cookie);

	}

	tcf_set_action_cookie(&p->act_cookie, NULL);

	if (p->goto_chain)

		tcf_action_goto_chain_fini(p);
@@ -567,16 +582,22 @@ tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 
	int err = -EINVAL;

	unsigned char *b = skb_tail_pointer(skb);

	struct nlattr *nest;

	struct tc_cookie *cookie;



	if (nla_put_string(skb, TCA_KIND, a->ops->kind))

		goto nla_put_failure;

	if (tcf_action_copy_stats(skb, a, 0))

		goto nla_put_failure;

	if (a->act_cookie) {

		if (nla_put(skb, TCA_ACT_COOKIE, a->act_cookie->len,

			    a->act_cookie->data))



	rcu_read_lock();

	cookie = rcu_dereference(a->act_cookie);

	if (cookie) {

		if (nla_put(skb, TCA_ACT_COOKIE, cookie->len, cookie->data)) {

			rcu_read_unlock();

			goto nla_put_failure;

		}

	}

	rcu_read_unlock();



	nest = nla_nest_start(skb, TCA_OPTIONS);

	if (nest == NULL)
@@ -719,13 +740,8 @@ struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp, 
	if (err < 0)

		goto err_mod;



	if (name == NULL && tb[TCA_ACT_COOKIE]) {

		if (a->act_cookie) {

			kfree(a->act_cookie->data);

			kfree(a->act_cookie);

		}

		a->act_cookie = cookie;

	}

	if (!name && tb[TCA_ACT_COOKIE])

		tcf_set_action_cookie(&a->act_cookie, cookie);



	/* module count goes up only when brand new policy is created

	 * if it exists and is only bound to in a_o->init() then