netdev - [RFC V3 PATCH 13/26] net/netpolicy: support CPU hotplug

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Message-Id: <1473692159-4017-14-git-send-email-kan.liang@intel.com>
Date:   Mon, 12 Sep 2016 07:55:46 -0700
From:   kan.liang@...el.com
To:     davem@...emloft.net, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org
Cc:     jeffrey.t.kirsher@...el.com, mingo@...hat.com,
        peterz@...radead.org, kuznet@....inr.ac.ru, jmorris@...ei.org,
        yoshfuji@...ux-ipv6.org, kaber@...sh.net,
        akpm@...ux-foundation.org, keescook@...omium.org,
        viro@...iv.linux.org.uk, gorcunov@...nvz.org,
        john.stultz@...aro.org, aduyck@...antis.com, ben@...adent.org.uk,
        decot@...glers.com, fw@...len.de, alexander.duyck@...il.com,
        daniel@...earbox.net, tom@...bertland.com, rdunlap@...radead.org,
        xiyou.wangcong@...il.com, hannes@...essinduktion.org,
        stephen@...workplumber.org, alexei.starovoitov@...il.com,
        jesse.brandeburg@...el.com, andi@...stfloor.org,
        Kan Liang <kan.liang@...el.com>
Subject: [RFC V3 PATCH 13/26] net/netpolicy: support CPU hotplug

From: Kan Liang <kan.liang@...el.com>

For CPU hotplug, the NET policy subsystem will rebuild the sys map and
object list.

Signed-off-by: Kan Liang <kan.liang@...el.com>
---
 net/core/netpolicy.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)

diff --git a/net/core/netpolicy.c b/net/core/netpolicy.c
index 271ecc3..3bf0a44 100644
--- a/net/core/netpolicy.c
+++ b/net/core/netpolicy.c
@@ -38,6 +38,7 @@
 #include <net/rtnetlink.h>
 #include <linux/sort.h>
 #include <linux/ctype.h>
+#include <linux/cpu.h>
 
 static int netpolicy_get_dev_info(struct net_device *dev,
 				  struct netpolicy_dev_info *d_info)
@@ -846,6 +847,77 @@ static struct notifier_block netpolicy_dev_notf = {
 	.notifier_call = netpolicy_notify,
 };
 
+/**
+ * update_netpolicy_sys_map() - rebuild the sys map and object list
+ *
+ * This function go through all the available net policy supported device,
+ * and rebuild sys map and object list.
+ *
+ */
+void update_netpolicy_sys_map(void)
+{
+	struct net *net;
+	struct net_device *dev, *aux;
+	enum netpolicy_name cur_policy;
+
+	for_each_net(net) {
+		for_each_netdev_safe(net, dev, aux) {
+			spin_lock(&dev->np_lock);
+			if (!dev->netpolicy)
+				goto unlock;
+			cur_policy = dev->netpolicy->cur_policy;
+			if (cur_policy == NET_POLICY_NONE)
+				goto unlock;
+
+			dev->netpolicy->cur_policy = NET_POLICY_NONE;
+
+			/* rebuild everything */
+			netpolicy_disable(dev);
+			netpolicy_enable(dev);
+			if (netpolicy_gen_obj_list(dev, cur_policy)) {
+				pr_warn("NETPOLICY: Failed to generate netpolicy object list for dev %s\n",
+					dev->name);
+				netpolicy_disable(dev);
+				goto unlock;
+			}
+			if (dev->netdev_ops->ndo_set_net_policy(dev, cur_policy)) {
+				pr_warn("NETPOLICY: Failed to set netpolicy for dev %s\n",
+					dev->name);
+				netpolicy_disable(dev);
+				goto unlock;
+			}
+
+			dev->netpolicy->cur_policy = cur_policy;
+unlock:
+			spin_unlock(&dev->np_lock);
+		}
+	}
+}
+
+static int netpolicy_cpu_callback(struct notifier_block *nfb,
+				  unsigned long action, void *hcpu)
+{
+	switch (action & ~CPU_TASKS_FROZEN) {
+	case CPU_ONLINE:
+		rtnl_lock();
+		update_netpolicy_sys_map();
+		rtnl_unlock();
+		break;
+	case CPU_DYING:
+		rtnl_lock();
+		update_netpolicy_sys_map();
+		rtnl_unlock();
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block netpolicy_cpu_notifier = {
+	&netpolicy_cpu_callback,
+	NULL,
+	0
+};
+
 static int __init netpolicy_init(void)
 {
 	int ret;
@@ -854,6 +926,10 @@ static int __init netpolicy_init(void)
 	if (!ret)
 		register_netdevice_notifier(&netpolicy_dev_notf);
 
+	cpu_notifier_register_begin();
+	__register_cpu_notifier(&netpolicy_cpu_notifier);
+	cpu_notifier_register_done();
+
 	return ret;
 }
 
@@ -861,6 +937,10 @@ static void __exit netpolicy_exit(void)
 {
 	unregister_netdevice_notifier(&netpolicy_dev_notf);
 	unregister_pernet_subsys(&netpolicy_net_ops);
+
+	cpu_notifier_register_begin();
+	__unregister_cpu_notifier(&netpolicy_cpu_notifier);
+	cpu_notifier_register_done();
 }
 
 subsys_initcall(netpolicy_init);
-- 
2.5.5