net_sched: act_pedit: use RCU in tcf_pedit_dump()

Also storing tcf_action into struct tcf_pedit_params
makes sure there is no discrepancy in tcf_pedit_act().

Signed-off-by: Eric Dumazet <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

include/net/tc_act/tc_pedit.h

···
 struct tcf_pedit_parms {
 	struct tc_pedit_key	*tcfp_keys;
 	struct tcf_pedit_key_ex	*tcfp_keys_ex;
+	int action;
 	u32 tcfp_off_max_hint;
 	unsigned char tcfp_nkeys;
 	unsigned char tcfp_flags;

net/sched/act_pedit.c

···
 	}
 
 	p = to_pedit(*a);
-
+	nparms->action = parm->action;
 	spin_lock_bh(&p->tcf_lock);
 	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 	oparms = rcu_replace_pointer(p->parms, nparms, 1);
···
 bad:
 	tcf_action_inc_overlimit_qstats(&p->common);
 done:
-	return p->tcf_action;
+	return parms->action;
 }
 
 static void tcf_pedit_stats_update(struct tc_action *a, u64 bytes, u64 packets,
···
 			  int bind, int ref)
 {
 	unsigned char *b = skb_tail_pointer(skb);
-	struct tcf_pedit *p = to_pedit(a);
-	struct tcf_pedit_parms *parms;
+	const struct tcf_pedit *p = to_pedit(a);
+	const struct tcf_pedit_parms *parms;
 	struct tc_pedit *opt;
 	struct tcf_t t;
 	int s;
 
-	spin_lock_bh(&p->tcf_lock);
-	parms = rcu_dereference_protected(p->parms, 1);
+	rcu_read_lock();
+	parms = rcu_dereference(p->parms);
 	s = struct_size(opt, keys, parms->tcfp_nkeys);
 
 	opt = kzalloc(s, GFP_ATOMIC);
 	if (unlikely(!opt)) {
-		spin_unlock_bh(&p->tcf_lock);
+		rcu_read_unlock();
 		return -ENOBUFS;
 	}
 	opt->nkeys = parms->tcfp_nkeys;
···
 	       flex_array_size(opt, keys, parms->tcfp_nkeys));
 	opt->index = p->tcf_index;
 	opt->flags = parms->tcfp_flags;
-	opt->action = p->tcf_action;
+	opt->action = parms->action;
 	opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
 	opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
 
···
 	tcf_tm_dump(&t, &p->tcf_tm);
 	if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
 		goto nla_put_failure;
-	spin_unlock_bh(&p->tcf_lock);
+	rcu_read_unlock();
 
 	kfree(opt);
 	return skb->len;
 
 nla_put_failure:
-	spin_unlock_bh(&p->tcf_lock);
+	rcu_read_unlock();
 	nlmsg_trim(skb, b);
 	kfree(opt);
 	return -1;