1 files changed, 22 insertions, 12 deletions

diff --git a/net/sched/cls_fw.c b/net/sched/cls_fw.c
index a5269f76004c..715e01e5910a 100644
--- a/net/sched/cls_fw.c
+++ b/net/sched/cls_fw.c
@@ -33,6 +33,7 @@
 
 struct fw_head {
 	u32			mask;
+	bool			mask_set;
 	struct fw_filter __rcu	*ht[HTSIZE];
 	struct rcu_head		rcu;
 };
@@ -113,6 +114,14 @@ static unsigned long fw_get(struct tcf_proto *tp, u32 handle)
 
 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);
 	return 0;
 }
 
@@ -124,14 +133,20 @@ static void fw_delete_filter(struct rcu_head *head)
 	kfree(f);
 }
 
-static void fw_destroy(struct tcf_proto *tp)
+static bool fw_destroy(struct tcf_proto *tp, bool force)
 {
 	struct fw_head *head = rtnl_dereference(tp->root);
 	struct fw_filter *f;
 	int h;
 
 	if (head == NULL)
-		return;
+		return true;
+
+	if (!force) {
+		for (h = 0; h < HTSIZE; h++)
+			if (rcu_access_pointer(head->ht[h]))
+				return false;
+	}
 
 	for (h = 0; h < HTSIZE; h++) {
 		while ((f = rtnl_dereference(head->ht[h])) != NULL) {
@@ -143,6 +158,7 @@ static void fw_destroy(struct tcf_proto *tp)
 	}
 	RCU_INIT_POINTER(tp->root, NULL);
 	kfree_rcu(head, rcu);
+	return true;
 }
 
 static int fw_delete(struct tcf_proto *tp, unsigned long arg)
@@ -286,17 +302,11 @@ static int fw_change(struct net *net, struct sk_buff *in_skb,
 	if (!handle)
 		return -EINVAL;
 
-	if (head == NULL) {
-		u32 mask = 0xFFFFFFFF;
+	if (!head->mask_set) {
+		head->mask = 0xFFFFFFFF;
 		if (tb[TCA_FW_MASK])
-			mask = nla_get_u32(tb[TCA_FW_MASK]);
-
-		head = kzalloc(sizeof(struct fw_head), GFP_KERNEL);
-		if (head == NULL)
-			return -ENOBUFS;
-		head->mask = mask;
-
-		rcu_assign_pointer(tp->root, head);
+			head->mask = nla_get_u32(tb[TCA_FW_MASK]);
+		head->mask_set = true;
 	}
 
 	f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);