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Message-ID: <20100722104256.5a7e7cb6@nehalam>
Date: Thu, 22 Jul 2010 10:42:56 -0700
From: Stephen Hemminger <shemminger@...tta.com>
To: hadi@...erus.ca
Cc: David Miller <davem@...emloft.net>, netdev@...r.kernel.org
Subject: Re: mirred, redirect action vs. dev refcount issue
This is what I am testing now.
--- a/include/net/tc_act/tc_mirred.h 2010-07-22 09:17:41.631561924 -0700
+++ b/include/net/tc_act/tc_mirred.h 2010-07-22 09:49:53.355325645 -0700
@@ -9,6 +9,7 @@ struct tcf_mirred {
int tcfm_ifindex;
int tcfm_ok_push;
struct net_device *tcfm_dev;
+ struct list_head tcfm_list;
};
#define to_mirred(pc) \
container_of(pc, struct tcf_mirred, common)
--- a/net/sched/act_mirred.c 2010-07-21 16:10:48.922308036 -0700
+++ b/net/sched/act_mirred.c 2010-07-22 09:52:32.229910928 -0700
@@ -1,3 +1,4 @@
+
/*
* net/sched/mirred.c packet mirroring and redirect actions
*
@@ -21,6 +22,7 @@
#include <linux/module.h>
#include <linux/init.h>
#include <linux/gfp.h>
+#include <linux/notifier.h>
#include <net/net_namespace.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
@@ -33,6 +35,7 @@
static struct tcf_common *tcf_mirred_ht[MIRRED_TAB_MASK + 1];
static u32 mirred_idx_gen;
static DEFINE_RWLOCK(mirred_lock);
+static LIST_HEAD(mirred_list);
static struct tcf_hashinfo mirred_hash_info = {
.htab = tcf_mirred_ht,
@@ -47,7 +50,10 @@ static inline int tcf_mirred_release(str
m->tcf_bindcnt--;
m->tcf_refcnt--;
if(!m->tcf_bindcnt && m->tcf_refcnt <= 0) {
- dev_put(m->tcfm_dev);
+ ASSERT_RTNL();
+ list_del(&m->tcfm_list);
+ if (m->tcfm_dev)
+ dev_put(m->tcfm_dev);
tcf_hash_destroy(&m->common, &mirred_hash_info);
return 1;
}
@@ -134,8 +140,11 @@ static int tcf_mirred_init(struct nlattr
m->tcfm_ok_push = ok_push;
}
spin_unlock_bh(&m->tcf_lock);
- if (ret == ACT_P_CREATED)
+ if (ret == ACT_P_CREATED) {
+ ASSERT_RTNL();
+ list_add(&m->tcfm_list, &mirred_list);
tcf_hash_insert(pc, &mirred_hash_info);
+ }
return ret;
}
@@ -164,9 +173,14 @@ static int tcf_mirred(struct sk_buff *sk
m->tcf_bstats.packets++;
dev = m->tcfm_dev;
+ if (!dev) {
+ printk_once(KERN_NOTICE "tc mirred: target device is gone\n");
+ goto out;
+ }
+
if (!(dev->flags & IFF_UP)) {
if (net_ratelimit())
- pr_notice("tc mirred to Houston: device %s is gone!\n",
+ pr_notice("tc mirred to Houston: device %s is down\n",
dev->name);
goto out;
}
@@ -230,6 +244,28 @@ nla_put_failure:
return -1;
}
+static int mirred_device_event(struct notifier_block *unused,
+ unsigned long event, void *ptr)
+{
+ struct net_device *dev = ptr;
+ struct tcf_mirred *m;
+
+ if (event == NETDEV_UNREGISTER)
+ list_for_each_entry(m, &mirred_list, tcfm_list) {
+ if (m->tcfm_dev == dev) {
+ dev_put(dev);
+ m->tcfm_dev = NULL;
+ }
+ }
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block mirred_device_notifier = {
+ .notifier_call = mirred_device_event,
+};
+
+
static struct tc_action_ops act_mirred_ops = {
.kind = "mirred",
.hinfo = &mirred_hash_info,
@@ -250,12 +286,17 @@ MODULE_LICENSE("GPL");
static int __init mirred_init_module(void)
{
+ int err = register_netdevice_notifier(&mirred_device_notifier);
+ if (err)
+ return err;
+
pr_info("Mirror/redirect action on\n");
return tcf_register_action(&act_mirred_ops);
}
static void __exit mirred_cleanup_module(void)
{
+ unregister_netdevice_notifier(&mirred_device_notifier);
tcf_unregister_action(&act_mirred_ops);
}
--
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