net: sched: act_pedit: remove dependency on rtnl lock

w1ldptr · davem330 · commit 67b0c1a3c9ce · 2018-08-11T12:37:09.000-07:00
Rearrange pedit init code to only access pedit action data while holding
tcf spinlock. Change keys allocation type to atomic to allow it to execute
while holding tcf spinlock. Take tcf spinlock in dump function when
accessing pedit action data.

Signed-off-by: Vlad Buslov &lt;vladbu@mellanox.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
@@ -187,51 +187,48 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 			tcf_idr_cleanup(tn, parm->index);
 			goto out_free;
 		}
-		p = to_pedit(*a);
-		keys = kmalloc(ksize, GFP_KERNEL);
-		if (!keys) {
-			tcf_idr_release(*a, bind);
-			ret = -ENOMEM;
-			goto out_free;
-		}
 		ret = ACT_P_CREATED;
 	} else if (err > 0) {
 		if (bind)
 			goto out_free;
 		if (!ovr) {
-			tcf_idr_release(*a, bind);
 			ret = -EEXIST;
-			goto out_free;
-		}
-		p = to_pedit(*a);
-		if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
-			keys = kmalloc(ksize, GFP_KERNEL);
-			if (!keys) {
-				ret = -ENOMEM;
-				goto out_free;
-			}
+			goto out_release;
 		}
 	} else {
 		return err;
 	}
 
+	p = to_pedit(*a);
 	spin_lock_bh(&p->tcf_lock);
-	p->tcfp_flags = parm->flags;
-	p->tcf_action = parm->action;
-	if (keys) {
+
+	if (ret == ACT_P_CREATED ||
+	    (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
+		keys = kmalloc(ksize, GFP_ATOMIC);
+		if (!keys) {
+			spin_unlock_bh(&p->tcf_lock);
+			ret = -ENOMEM;
+			goto out_release;
+		}
 		kfree(p->tcfp_keys);
 		p->tcfp_keys = keys;
 		p->tcfp_nkeys = parm->nkeys;
 	}
 	memcpy(p->tcfp_keys, parm->keys, ksize);
 
+	p->tcfp_flags = parm->flags;
+	p->tcf_action = parm->action;
+
 	kfree(p->tcfp_keys_ex);
 	p->tcfp_keys_ex = keys_ex;
 
 	spin_unlock_bh(&p->tcf_lock);
 	if (ret == ACT_P_CREATED)
 		tcf_idr_insert(tn, *a);
 	return ret;
+
+out_release:
+	tcf_idr_release(*a, bind);
 out_free:
 	kfree(keys_ex);
 	return ret;
@@ -410,6 +407,7 @@ static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 	if (unlikely(!opt))
 		return -ENOBUFS;
 
+	spin_lock_bh(&p->tcf_lock);
 	memcpy(opt->keys, p->tcfp_keys,
 	       p->tcfp_nkeys * sizeof(struct tc_pedit_key));
 	opt->index = p->tcf_index;
@@ -432,11 +430,13 @@ static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 	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);
 
 	kfree(opt);
 	return skb->len;
 
 nla_put_failure:
+	spin_unlock_bh(&p->tcf_lock);
 	nlmsg_trim(skb, b);
 	kfree(opt);
 	return -1;
