net: sched: introduce tcf block infractructure

Currently, the filter chains are direcly put into the private structures
of qdiscs. In order to be able to have multiple chains per qdisc and to
allow filter chains sharing among qdiscs, there is a need for common
object that would hold the chains. This introduces such object and calls
it "tcf_block".

Helpers to get and put the blocks are provided to be called from
individual qdisc code. Also, the original filter_list pointers are left
in qdisc privs to allow the entry into tcf_block processing without any
added overhead of possible multiple pointer dereference on fast path.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 8 deletions

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 640f5f3..195bbca9 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -105,6 +105,7 @@ struct htb_class {
 	int			quantum;	/* but stored for parent-to-leaf return */
 
 	struct tcf_proto __rcu	*filter_list;	/* class attached filters */
+	struct tcf_block	*block;
 	int			filter_cnt;
 	int			refcnt;		/* usage count of this class */
 
@@ -156,6 +157,7 @@ struct htb_sched {
 
 	/* filters for qdisc itself */
 	struct tcf_proto __rcu	*filter_list;
+	struct tcf_block	*block;
 
 #define HTB_WARN_TOOMANYEVENTS	0x1
 	unsigned int		warned;	/* only one warning */
@@ -1017,6 +1019,10 @@ static int htb_init(struct Qdisc *sch, struct nlattr *opt)
 	if (!opt)
 		return -EINVAL;
 
+	err = tcf_block_get(&q->block, &q->filter_list);
+	if (err)
+		return err;
+
 	err = nla_parse_nested(tb, TCA_HTB_MAX, opt, htb_policy, NULL);
 	if (err < 0)
 		return err;
@@ -1230,7 +1236,7 @@ static void htb_destroy_class(struct Qdisc *sch, struct htb_class *cl)
 		qdisc_destroy(cl->un.leaf.q);
 	}
 	gen_kill_estimator(&cl->rate_est);
-	tcf_destroy_chain(&cl->filter_list);
+	tcf_block_put(cl->block);
 	kfree(cl);
 }
 
@@ -1248,11 +1254,11 @@ static void htb_destroy(struct Qdisc *sch)
 	 * because filter need its target class alive to be able to call
 	 * unbind_filter on it (without Oops).
 	 */
-	tcf_destroy_chain(&q->filter_list);
+	tcf_block_put(q->block);
 
 	for (i = 0; i < q->clhash.hashsize; i++) {
 		hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode)
-			tcf_destroy_chain(&cl->filter_list);
+			tcf_block_put(cl->block);
 	}
 	for (i = 0; i < q->clhash.hashsize; i++) {
 		hlist_for_each_entry_safe(cl, next, &q->clhash.hash[i],
@@ -1396,6 +1402,11 @@ static int htb_change_class(struct Qdisc *sch, u32 classid,
 		if (!cl)
 			goto failure;
 
+		err = tcf_block_get(&cl->block, &cl->filter_list);
+		if (err) {
+			kfree(cl);
+			goto failure;
+		}
 		if (htb_rate_est || tca[TCA_RATE]) {
 			err = gen_new_estimator(&cl->bstats, NULL,
 						&cl->rate_est,
@@ -1403,6 +1414,7 @@ static int htb_change_class(struct Qdisc *sch, u32 classid,
 						qdisc_root_sleeping_running(sch),
 						tca[TCA_RATE] ? : &est.nla);
 			if (err) {
+				tcf_block_put(cl->block);
 				kfree(cl);
 				goto failure;
 			}
@@ -1521,14 +1533,12 @@ failure:
 	return err;
 }
 
-static struct tcf_proto __rcu **htb_find_tcf(struct Qdisc *sch,
-					     unsigned long arg)
+static struct tcf_block *htb_tcf_block(struct Qdisc *sch, unsigned long arg)
 {
 	struct htb_sched *q = qdisc_priv(sch);
 	struct htb_class *cl = (struct htb_class *)arg;
-	struct tcf_proto __rcu **fl = cl ? &cl->filter_list : &q->filter_list;
 
-	return fl;
+	return cl ? cl->block : q->block;
 }
 
 static unsigned long htb_bind_filter(struct Qdisc *sch, unsigned long parent,
@@ -1591,7 +1601,7 @@ static const struct Qdisc_class_ops htb_class_ops = {
 	.change		=	htb_change_class,
 	.delete		=	htb_delete,
 	.walk		=	htb_walk,
-	.tcf_chain	=	htb_find_tcf,
+	.tcf_block	=	htb_tcf_block,
 	.bind_tcf	=	htb_bind_filter,
 	.unbind_tcf	=	htb_unbind_filter,
 	.dump		=	htb_dump_class,