Patch "net: revert "net_sched: move tp->root allocation into fw_init()"" has been added to the 4.1-stable tree

@@ -33,7 +33,6 @@
 
 struct fw_head {
 	u32			mask;
-	bool			mask_set;
 	struct fw_filter __rcu	*ht[HTSIZE];
 	struct rcu_head		rcu;
 };

@@ -84,7 +83,7 @@ static int fw_classify(struct sk_buff *s
 			}
 		}
 	} else {
-		/* old method */
+		/* Old method: classify the packet using its skb mark. */
 		if (id && (TC_H_MAJ(id) == 0 ||
 			   !(TC_H_MAJ(id ^ tp->q->handle)))) {
 			res->classid = id;

@@ -114,14 +113,9 @@ static unsigned long fw_get(struct tcf_p
 
 static int fw_init(struct tcf_proto *tp)
 {
-	struct fw_head *head;
-
-	head = kzalloc(sizeof(struct fw_head), GFP_KERNEL);
-	if (head == NULL)
-		return -ENOBUFS;
-
-	head->mask_set = false;
-	rcu_assign_pointer(tp->root, head);
+	/* We don't allocate fw_head here, because in the old method
+	 * we don't need it at all.
+	 */
 	return 0;
 }
 

@@ -252,7 +246,7 @@ static int fw_change(struct net *net, st
 	int err;
 
 	if (!opt)
-		return handle ? -EINVAL : 0;
+		return handle ? -EINVAL : 0; /* Succeed if it is old method. */
 
 	err = nla_parse_nested(tb, TCA_FW_MAX, opt, fw_policy);
 	if (err < 0)

@@ -302,11 +296,17 @@ static int fw_change(struct net *net, st
 	if (!handle)
 		return -EINVAL;
 
-	if (!head->mask_set) {
-		head->mask = 0xFFFFFFFF;
+	if (!head) {
+		u32 mask = 0xFFFFFFFF;
 		if (tb[TCA_FW_MASK])
-			head->mask = nla_get_u32(tb[TCA_FW_MASK]);
-		head->mask_set = true;
+			mask = nla_get_u32(tb[TCA_FW_MASK]);
+
+		head = kzalloc(sizeof(*head), GFP_KERNEL);
+		if (!head)
+			return -ENOBUFS;
+		head->mask = mask;
+
+		rcu_assign_pointer(tp->root, head);
 	}
 
 	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);