net: sched: cls_u32: Undo tcf_bind_filter if u32_replace_hw_knode

When u32_replace_hw_knode fails, we need to undo the tcf_bind_filter
operation done at u32_set_parms.

Fixes: d34e3e1813 ("net: cls_u32: Add support for skip-sw flag to tc u32 classifier.")
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Pedro Tammela <pctammela@mojatatu.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/cls_u32.c

@@ -712,8 +712,23 @@ static const struct nla_policy u32_policy[TCA_U32_MAX + 1] = {
 	[TCA_U32_FLAGS]		= { .type = NLA_U32 },
 };
 
+static void u32_unbind_filter(struct tcf_proto *tp, struct tc_u_knode *n,
+			      struct nlattr **tb)
+{
+	if (tb[TCA_U32_CLASSID])
+		tcf_unbind_filter(tp, &n->res);
+}
+
+static void u32_bind_filter(struct tcf_proto *tp, struct tc_u_knode *n,
+			    unsigned long base, struct nlattr **tb)
+{
+	if (tb[TCA_U32_CLASSID]) {
+		n->res.classid = nla_get_u32(tb[TCA_U32_CLASSID]);
+		tcf_bind_filter(tp, &n->res, base);
+	}
+}
+
 static int u32_set_parms(struct net *net, struct tcf_proto *tp,
-			 unsigned long base,
 			 struct tc_u_knode *n, struct nlattr **tb,
 			 struct nlattr *est, u32 flags, u32 fl_flags,
 			 struct netlink_ext_ack *extack)
@@ -760,10 +775,6 @@ static int u32_set_parms(struct net *net, struct tcf_proto *tp,
 		if (ht_old)
 			ht_old->refcnt--;
 	}
-	if (tb[TCA_U32_CLASSID]) {
-		n->res.classid = nla_get_u32(tb[TCA_U32_CLASSID]);
-		tcf_bind_filter(tp, &n->res, base);
-	}
 
 	if (ifindex >= 0)
 		n->ifindex = ifindex;
@@ -903,17 +914,20 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 		if (!new)
 			return -ENOMEM;
 
-		err = u32_set_parms(net, tp, base, new, tb,
-				    tca[TCA_RATE], flags, new->flags,
-				    extack);
+		err = u32_set_parms(net, tp, new, tb, tca[TCA_RATE],
+				    flags, new->flags, extack);
 
 		if (err) {
 			__u32_destroy_key(new);
 			return err;
 		}
 
+		u32_bind_filter(tp, new, base, tb);
+
 		err = u32_replace_hw_knode(tp, new, flags, extack);
 		if (err) {
+			u32_unbind_filter(tp, new, tb);
+
 			__u32_destroy_key(new);
 			return err;
 		}
@@ -1074,15 +1088,18 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 	}
 #endif
 
-	err = u32_set_parms(net, tp, base, n, tb, tca[TCA_RATE],
+	err = u32_set_parms(net, tp, n, tb, tca[TCA_RATE],
 			    flags, n->flags, extack);
+
+	u32_bind_filter(tp, n, base, tb);
+
 	if (err == 0) {
 		struct tc_u_knode __rcu **ins;
 		struct tc_u_knode *pins;
 
 		err = u32_replace_hw_knode(tp, n, flags, extack);
 		if (err)
-			goto errhw;
+			goto errunbind;
 
 		if (!tc_in_hw(n->flags))
 			n->flags |= TCA_CLS_FLAGS_NOT_IN_HW;
@@ -1100,7 +1117,9 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 		return 0;
 	}
 
-errhw:
+errunbind:
+	u32_unbind_filter(tp, n, tb);
+
 #ifdef CONFIG_CLS_U32_MARK
 	free_percpu(n->pcpu_success);
 #endif