net_sched: switch to rcu_work

Commit 05f0fe6b74db ("RCU, workqueue: Implement rcu_work") introduces
new API's for dispatching work in a RCU callback. Now we can just
switch to the new API's for tc filters. This could get rid of a lot
of code.

Cc: Tejun Heo <tj@kernel.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c
index b07c1fa..1aa7f65 100644
--- a/net/sched/cls_bpf.c
+++ b/net/sched/cls_bpf.c
@@ -49,10 +49,7 @@ struct cls_bpf_prog {
 	struct sock_filter *bpf_ops;
 	const char *bpf_name;
 	struct tcf_proto *tp;
-	union {
-		struct work_struct work;
-		struct rcu_head rcu;
-	};
+	struct rcu_work rwork;
 };
 
 static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = {
@@ -275,21 +272,14 @@ static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
 
 static void cls_bpf_delete_prog_work(struct work_struct *work)
 {
-	struct cls_bpf_prog *prog = container_of(work, struct cls_bpf_prog, work);
-
+	struct cls_bpf_prog *prog = container_of(to_rcu_work(work),
+						 struct cls_bpf_prog,
+						 rwork);
 	rtnl_lock();
 	__cls_bpf_delete_prog(prog);
 	rtnl_unlock();
 }
 
-static void cls_bpf_delete_prog_rcu(struct rcu_head *rcu)
-{
-	struct cls_bpf_prog *prog = container_of(rcu, struct cls_bpf_prog, rcu);
-
-	INIT_WORK(&prog->work, cls_bpf_delete_prog_work);
-	tcf_queue_work(&prog->work);
-}
-
 static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 			     struct netlink_ext_ack *extack)
 {
@@ -300,7 +290,7 @@ static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 	list_del_rcu(&prog->link);
 	tcf_unbind_filter(tp, &prog->res);
 	if (tcf_exts_get_net(&prog->exts))
-		call_rcu(&prog->rcu, cls_bpf_delete_prog_rcu);
+		tcf_queue_work(&prog->rwork, cls_bpf_delete_prog_work);
 	else
 		__cls_bpf_delete_prog(prog);
 }
@@ -526,7 +516,7 @@ static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
 		list_replace_rcu(&oldprog->link, &prog->link);
 		tcf_unbind_filter(tp, &oldprog->res);
 		tcf_exts_get_net(&oldprog->exts);
-		call_rcu(&oldprog->rcu, cls_bpf_delete_prog_rcu);
+		tcf_queue_work(&oldprog->rwork, cls_bpf_delete_prog_work);
 	} else {
 		list_add_rcu(&prog->link, &head->plist);
 	}