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_flower.c b/net/sched/cls_flower.c
index eacaaf8..4e74508 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -73,10 +73,7 @@
 struct cls_fl_head {
 	struct rhashtable ht;
 	struct list_head masks;
-	union {
-		struct work_struct work;
-		struct rcu_head	rcu;
-	};
+	struct rcu_work rwork;
 	struct idr handle_idr;
 };
 
@@ -90,10 +87,7 @@
 	struct list_head list;
 	u32 handle;
 	u32 flags;
-	union {
-		struct work_struct work;
-		struct rcu_head	rcu;
-	};
+	struct rcu_work rwork;
 	struct net_device *hw_dev;
 };
 
@@ -235,21 +229,14 @@
 
 static void fl_destroy_filter_work(struct work_struct *work)
 {
-	struct cls_fl_filter *f = container_of(work, struct cls_fl_filter, work);
+	struct cls_fl_filter *f = container_of(to_rcu_work(work),
+					struct cls_fl_filter, rwork);
 
 	rtnl_lock();
 	__fl_destroy_filter(f);
 	rtnl_unlock();
 }
 
-static void fl_destroy_filter(struct rcu_head *head)
-{
-	struct cls_fl_filter *f = container_of(head, struct cls_fl_filter, rcu);
-
-	INIT_WORK(&f->work, fl_destroy_filter_work);
-	tcf_queue_work(&f->work);
-}
-
 static void fl_hw_destroy_filter(struct tcf_proto *tp, struct cls_fl_filter *f,
 				 struct netlink_ext_ack *extack)
 {
@@ -327,7 +314,7 @@
 		fl_hw_destroy_filter(tp, f, extack);
 	tcf_unbind_filter(tp, &f->res);
 	if (async)
-		call_rcu(&f->rcu, fl_destroy_filter);
+		tcf_queue_work(&f->rwork, fl_destroy_filter_work);
 	else
 		__fl_destroy_filter(f);
 
@@ -336,20 +323,13 @@
 
 static void fl_destroy_sleepable(struct work_struct *work)
 {
-	struct cls_fl_head *head = container_of(work, struct cls_fl_head,
-						work);
+	struct cls_fl_head *head = container_of(to_rcu_work(work),
+						struct cls_fl_head,
+						rwork);
 	kfree(head);
 	module_put(THIS_MODULE);
 }
 
-static void fl_destroy_rcu(struct rcu_head *rcu)
-{
-	struct cls_fl_head *head = container_of(rcu, struct cls_fl_head, rcu);
-
-	INIT_WORK(&head->work, fl_destroy_sleepable);
-	schedule_work(&head->work);
-}
-
 static void fl_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack)
 {
 	struct cls_fl_head *head = rtnl_dereference(tp->root);
@@ -365,7 +345,7 @@
 	idr_destroy(&head->handle_idr);
 
 	__module_get(THIS_MODULE);
-	call_rcu(&head->rcu, fl_destroy_rcu);
+	tcf_queue_work(&head->rwork, fl_destroy_sleepable);
 }
 
 static void *fl_get(struct tcf_proto *tp, u32 handle)
@@ -1036,7 +1016,7 @@
 		list_replace_rcu(&fold->list, &fnew->list);
 		tcf_unbind_filter(tp, &fold->res);
 		tcf_exts_get_net(&fold->exts);
-		call_rcu(&fold->rcu, fl_destroy_filter);
+		tcf_queue_work(&fold->rwork, fl_destroy_filter_work);
 	} else {
 		list_add_tail_rcu(&fnew->list, &fnew->mask->filters);
 	}