linux-stable/net/sched/sch_ingress.c
WANG Cong 143976ce99 net_sched: remove tc class reference counting
For TC classes, their ->get() and ->put() are always paired, and the
reference counting is completely useless, because:

1) For class modification and dumping paths, we already hold RTNL lock,
   so all of these ->get(),->change(),->put() are atomic.

2) For filter bindiing/unbinding, we use other reference counter than
   this one, and they should have RTNL lock too.

3) For ->qlen_notify(), it is special because it is called on ->enqueue()
   path, but we already hold qdisc tree lock there, and we hold this
   tree lock when graft or delete the class too, so it should not be gone
   or changed until we release the tree lock.

Therefore, this patch removes ->get() and ->put(), but:

1) Adds a new ->find() to find the pointer to a class by classid, no
   refcnt.

2) Move the original class destroy upon the last refcnt into ->delete(),
   right after releasing tree lock. This is fine because the class is
   already removed from hash when holding the lock.

For those who also use ->put() as ->unbind(), just rename them to reflect
this change.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-25 17:19:10 -07:00

226 lines
4.8 KiB
C

/* net/sched/sch_ingress.c - Ingress and clsact qdisc
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Authors: Jamal Hadi Salim 1999
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>
struct ingress_sched_data {
struct tcf_block *block;
};
static struct Qdisc *ingress_leaf(struct Qdisc *sch, unsigned long arg)
{
return NULL;
}
static unsigned long ingress_find(struct Qdisc *sch, u32 classid)
{
return TC_H_MIN(classid) + 1;
}
static unsigned long ingress_bind_filter(struct Qdisc *sch,
unsigned long parent, u32 classid)
{
return ingress_find(sch, classid);
}
static void ingress_unbind_filter(struct Qdisc *sch, unsigned long cl)
{
}
static void ingress_walk(struct Qdisc *sch, struct qdisc_walker *walker)
{
}
static struct tcf_block *ingress_tcf_block(struct Qdisc *sch, unsigned long cl)
{
struct ingress_sched_data *q = qdisc_priv(sch);
return q->block;
}
static int ingress_init(struct Qdisc *sch, struct nlattr *opt)
{
struct ingress_sched_data *q = qdisc_priv(sch);
struct net_device *dev = qdisc_dev(sch);
int err;
err = tcf_block_get(&q->block, &dev->ingress_cl_list);
if (err)
return err;
net_inc_ingress_queue();
sch->flags |= TCQ_F_CPUSTATS;
return 0;
}
static void ingress_destroy(struct Qdisc *sch)
{
struct ingress_sched_data *q = qdisc_priv(sch);
tcf_block_put(q->block);
net_dec_ingress_queue();
}
static int ingress_dump(struct Qdisc *sch, struct sk_buff *skb)
{
struct nlattr *nest;
nest = nla_nest_start(skb, TCA_OPTIONS);
if (nest == NULL)
goto nla_put_failure;
return nla_nest_end(skb, nest);
nla_put_failure:
nla_nest_cancel(skb, nest);
return -1;
}
static const struct Qdisc_class_ops ingress_class_ops = {
.leaf = ingress_leaf,
.find = ingress_find,
.walk = ingress_walk,
.tcf_block = ingress_tcf_block,
.bind_tcf = ingress_bind_filter,
.unbind_tcf = ingress_unbind_filter,
};
static struct Qdisc_ops ingress_qdisc_ops __read_mostly = {
.cl_ops = &ingress_class_ops,
.id = "ingress",
.priv_size = sizeof(struct ingress_sched_data),
.init = ingress_init,
.destroy = ingress_destroy,
.dump = ingress_dump,
.owner = THIS_MODULE,
};
struct clsact_sched_data {
struct tcf_block *ingress_block;
struct tcf_block *egress_block;
};
static unsigned long clsact_find(struct Qdisc *sch, u32 classid)
{
switch (TC_H_MIN(classid)) {
case TC_H_MIN(TC_H_MIN_INGRESS):
case TC_H_MIN(TC_H_MIN_EGRESS):
return TC_H_MIN(classid);
default:
return 0;
}
}
static unsigned long clsact_bind_filter(struct Qdisc *sch,
unsigned long parent, u32 classid)
{
return clsact_find(sch, classid);
}
static struct tcf_block *clsact_tcf_block(struct Qdisc *sch, unsigned long cl)
{
struct clsact_sched_data *q = qdisc_priv(sch);
switch (cl) {
case TC_H_MIN(TC_H_MIN_INGRESS):
return q->ingress_block;
case TC_H_MIN(TC_H_MIN_EGRESS):
return q->egress_block;
default:
return NULL;
}
}
static int clsact_init(struct Qdisc *sch, struct nlattr *opt)
{
struct clsact_sched_data *q = qdisc_priv(sch);
struct net_device *dev = qdisc_dev(sch);
int err;
err = tcf_block_get(&q->ingress_block, &dev->ingress_cl_list);
if (err)
return err;
err = tcf_block_get(&q->egress_block, &dev->egress_cl_list);
if (err)
return err;
net_inc_ingress_queue();
net_inc_egress_queue();
sch->flags |= TCQ_F_CPUSTATS;
return 0;
}
static void clsact_destroy(struct Qdisc *sch)
{
struct clsact_sched_data *q = qdisc_priv(sch);
tcf_block_put(q->egress_block);
tcf_block_put(q->ingress_block);
net_dec_ingress_queue();
net_dec_egress_queue();
}
static const struct Qdisc_class_ops clsact_class_ops = {
.leaf = ingress_leaf,
.find = clsact_find,
.walk = ingress_walk,
.tcf_block = clsact_tcf_block,
.bind_tcf = clsact_bind_filter,
.unbind_tcf = ingress_unbind_filter,
};
static struct Qdisc_ops clsact_qdisc_ops __read_mostly = {
.cl_ops = &clsact_class_ops,
.id = "clsact",
.priv_size = sizeof(struct clsact_sched_data),
.init = clsact_init,
.destroy = clsact_destroy,
.dump = ingress_dump,
.owner = THIS_MODULE,
};
static int __init ingress_module_init(void)
{
int ret;
ret = register_qdisc(&ingress_qdisc_ops);
if (!ret) {
ret = register_qdisc(&clsact_qdisc_ops);
if (ret)
unregister_qdisc(&ingress_qdisc_ops);
}
return ret;
}
static void __exit ingress_module_exit(void)
{
unregister_qdisc(&ingress_qdisc_ops);
unregister_qdisc(&clsact_qdisc_ops);
}
module_init(ingress_module_init);
module_exit(ingress_module_exit);
MODULE_ALIAS("sch_clsact");
MODULE_LICENSE("GPL");