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, 19 insertions, 8 deletions

diff --git a/net/sched/sch_atm.c b/net/sched/sch_atm.c
index 89d32fad9f89..f435546c3864 100644
--- a/net/sched/sch_atm.c
+++ b/net/sched/sch_atm.c
@@ -43,6 +43,7 @@
 struct atm_flow_data {
 	struct Qdisc		*q;	/* FIFO, TBF, etc. */
 	struct tcf_proto __rcu	*filter_list;
+	struct tcf_block	*block;
 	struct atm_vcc		*vcc;	/* VCC; NULL if VCC is closed */
 	void			(*old_pop)(struct atm_vcc *vcc,
 					   struct sk_buff *skb); /* chaining */
@@ -143,7 +144,7 @@ static void atm_tc_put(struct Qdisc *sch, unsigned long cl)
 	list_del_init(&flow->list);
 	pr_debug("atm_tc_put: qdisc %p\n", flow->q);
 	qdisc_destroy(flow->q);
-	tcf_destroy_chain(&flow->filter_list);
+	tcf_block_put(flow->block);
 	if (flow->sock) {
 		pr_debug("atm_tc_put: f_count %ld\n",
 			file_count(flow->sock->file));
@@ -274,7 +275,13 @@ static int atm_tc_change(struct Qdisc *sch, u32 classid, u32 parent,
 		error = -ENOBUFS;
 		goto err_out;
 	}
-	RCU_INIT_POINTER(flow->filter_list, NULL);
+
+	error = tcf_block_get(&flow->block, &flow->filter_list);
+	if (error) {
+		kfree(flow);
+		goto err_out;
+	}
+
 	flow->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, classid);
 	if (!flow->q)
 		flow->q = &noop_qdisc;
@@ -346,14 +353,13 @@ static void atm_tc_walk(struct Qdisc *sch, struct qdisc_walker *walker)
 	}
 }
 
-static struct tcf_proto __rcu **atm_tc_find_tcf(struct Qdisc *sch,
-						unsigned long cl)
+static struct tcf_block *atm_tc_tcf_block(struct Qdisc *sch, unsigned long cl)
 {
 	struct atm_qdisc_data *p = qdisc_priv(sch);
 	struct atm_flow_data *flow = (struct atm_flow_data *)cl;
 
 	pr_debug("atm_tc_find_tcf(sch %p,[qdisc %p],flow %p)\n", sch, p, flow);
-	return flow ? &flow->filter_list : &p->link.filter_list;
+	return flow ? flow->block : p->link.block;
 }
 
 /* --------------------------- Qdisc operations ---------------------------- */
@@ -524,6 +530,7 @@ static struct sk_buff *atm_tc_peek(struct Qdisc *sch)
 static int atm_tc_init(struct Qdisc *sch, struct nlattr *opt)
 {
 	struct atm_qdisc_data *p = qdisc_priv(sch);
+	int err;
 
 	pr_debug("atm_tc_init(sch %p,[qdisc %p],opt %p)\n", sch, p, opt);
 	INIT_LIST_HEAD(&p->flows);
@@ -534,7 +541,11 @@ static int atm_tc_init(struct Qdisc *sch, struct nlattr *opt)
 	if (!p->link.q)
 		p->link.q = &noop_qdisc;
 	pr_debug("atm_tc_init: link (%p) qdisc %p\n", &p->link, p->link.q);
-	RCU_INIT_POINTER(p->link.filter_list, NULL);
+
+	err = tcf_block_get(&p->link.block, &p->link.filter_list);
+	if (err)
+		return err;
+
 	p->link.vcc = NULL;
 	p->link.sock = NULL;
 	p->link.classid = sch->handle;
@@ -561,7 +572,7 @@ static void atm_tc_destroy(struct Qdisc *sch)
 
 	pr_debug("atm_tc_destroy(sch %p,[qdisc %p])\n", sch, p);
 	list_for_each_entry(flow, &p->flows, list)
-		tcf_destroy_chain(&flow->filter_list);
+		tcf_block_put(flow->block);
 
 	list_for_each_entry_safe(flow, tmp, &p->flows, list) {
 		if (flow->ref > 1)
@@ -646,7 +657,7 @@ static const struct Qdisc_class_ops atm_class_ops = {
 	.change		= atm_tc_change,
 	.delete		= atm_tc_delete,
 	.walk		= atm_tc_walk,
-	.tcf_chain	= atm_tc_find_tcf,
+	.tcf_block	= atm_tc_tcf_block,
 	.bind_tcf	= atm_tc_bind_filter,
 	.unbind_tcf	= atm_tc_put,
 	.dump		= atm_tc_dump_class,