1 files changed, 344 insertions, 0 deletions
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
new file mode 100644
index 00000000000..3a9fd4826b7
--- /dev/null
+++ b/net/core/netprio_cgroup.c
@@ -0,0 +1,344 @@
+/*
+ * net/core/netprio_cgroup.c	Priority Control Group
+ *
+ *		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:	Neil Horman <nhorman@tuxdriver.com>
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/skbuff.h>
+#include <linux/cgroup.h>
+#include <linux/rcupdate.h>
+#include <linux/atomic.h>
+#include <net/rtnetlink.h>
+#include <net/pkt_cls.h>
+#include <net/sock.h>
+#include <net/netprio_cgroup.h>
+
+static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss,
+					       struct cgroup *cgrp);
+static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp);
+static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp);
+
+struct cgroup_subsys net_prio_subsys = {
+	.name		= "net_prio",
+	.create		= cgrp_create,
+	.destroy	= cgrp_destroy,
+	.populate	= cgrp_populate,
+#ifdef CONFIG_NETPRIO_CGROUP
+	.subsys_id	= net_prio_subsys_id,
+#endif
+	.module		= THIS_MODULE
+};
+
+#define PRIOIDX_SZ 128
+
+static unsigned long prioidx_map[PRIOIDX_SZ];
+static DEFINE_SPINLOCK(prioidx_map_lock);
+static atomic_t max_prioidx = ATOMIC_INIT(0);
+
+static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgrp)
+{
+	return container_of(cgroup_subsys_state(cgrp, net_prio_subsys_id),
+			    struct cgroup_netprio_state, css);
+}
+
+static int get_prioidx(u32 *prio)
+{
+	unsigned long flags;
+	u32 prioidx;
+
+	spin_lock_irqsave(&prioidx_map_lock, flags);
+	prioidx = find_first_zero_bit(prioidx_map, sizeof(unsigned long) * PRIOIDX_SZ);
+	set_bit(prioidx, prioidx_map);
+	spin_unlock_irqrestore(&prioidx_map_lock, flags);
+	if (prioidx == sizeof(unsigned long) * PRIOIDX_SZ)
+		return -ENOSPC;
+
+	atomic_set(&max_prioidx, prioidx);
+	*prio = prioidx;
+	return 0;
+}
+
+static void put_prioidx(u32 idx)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&prioidx_map_lock, flags);
+	clear_bit(idx, prioidx_map);
+	spin_unlock_irqrestore(&prioidx_map_lock, flags);
+}
+
+static void extend_netdev_table(struct net_device *dev, u32 new_len)
+{
+	size_t new_size = sizeof(struct netprio_map) +
+			   ((sizeof(u32) * new_len));
+	struct netprio_map *new_priomap = kzalloc(new_size, GFP_KERNEL);
+	struct netprio_map *old_priomap;
+	int i;
+
+	old_priomap  = rtnl_dereference(dev->priomap);
+
+	if (!new_priomap) {
+		printk(KERN_WARNING "Unable to alloc new priomap!\n");
+		return;
+	}
+
+	for (i = 0;
+	     old_priomap && (i < old_priomap->priomap_len);
+	     i++)
+		new_priomap->priomap[i] = old_priomap->priomap[i];
+
+	new_priomap->priomap_len = new_len;
+
+	rcu_assign_pointer(dev->priomap, new_priomap);
+	if (old_priomap)
+		kfree_rcu(old_priomap, rcu);
+}
+
+static void update_netdev_tables(void)
+{
+	struct net_device *dev;
+	u32 max_len = atomic_read(&max_prioidx);
+	struct netprio_map *map;
+
+	rtnl_lock();
+	for_each_netdev(&init_net, dev) {
+		map = rtnl_dereference(dev->priomap);
+		if ((!map) ||
+		    (map->priomap_len < max_len))
+			extend_netdev_table(dev, max_len);
+	}
+	rtnl_unlock();
+}
+
+static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss,
+						 struct cgroup *cgrp)
+{
+	struct cgroup_netprio_state *cs;
+	int ret;
+
+	cs = kzalloc(sizeof(*cs), GFP_KERNEL);
+	if (!cs)
+		return ERR_PTR(-ENOMEM);
+
+	if (cgrp->parent && cgrp_netprio_state(cgrp->parent)->prioidx) {
+		kfree(cs);
+		return ERR_PTR(-EINVAL);
+	}
+
+	ret = get_prioidx(&cs->prioidx);
+	if (ret != 0) {
+		printk(KERN_WARNING "No space in priority index array\n");
+		kfree(cs);
+		return ERR_PTR(ret);
+	}
+
+	return &cs->css;
+}
+
+static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
+{
+	struct cgroup_netprio_state *cs;
+	struct net_device *dev;
+	struct netprio_map *map;
+
+	cs = cgrp_netprio_state(cgrp);
+	rtnl_lock();
+	for_each_netdev(&init_net, dev) {
+		map = rtnl_dereference(dev->priomap);
+		if (map)
+			map->priomap[cs->prioidx] = 0;
+	}
+	rtnl_unlock();
+	put_prioidx(cs->prioidx);
+	kfree(cs);
+}
+
+static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft)
+{
+	return (u64)cgrp_netprio_state(cgrp)->prioidx;
+}
+
+static int read_priomap(struct cgroup *cont, struct cftype *cft,
+			struct cgroup_map_cb *cb)
+{
+	struct net_device *dev;
+	u32 prioidx = cgrp_netprio_state(cont)->prioidx;
+	u32 priority;
+	struct netprio_map *map;
+
+	rcu_read_lock();
+	for_each_netdev_rcu(&init_net, dev) {
+		map = rcu_dereference(dev->priomap);
+		priority = map ? map->priomap[prioidx] : 0;
+		cb->fill(cb, dev->name, priority);
+	}
+	rcu_read_unlock();
+	return 0;
+}
+
+static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
+			 const char *buffer)
+{
+	char *devname = kstrdup(buffer, GFP_KERNEL);
+	int ret = -EINVAL;
+	u32 prioidx = cgrp_netprio_state(cgrp)->prioidx;
+	unsigned long priority;
+	char *priostr;
+	struct net_device *dev;
+	struct netprio_map *map;
+
+	if (!devname)
+		return -ENOMEM;
+
+	/*
+	 * Minimally sized valid priomap string
+	 */
+	if (strlen(devname) < 3)
+		goto out_free_devname;
+
+	priostr = strstr(devname, " ");
+	if (!priostr)
+		goto out_free_devname;
+
+	/*
+	 *Separate the devname from the associated priority
+	 *and advance the priostr poitner to the priority value
+	 */
+	*priostr = '\0';
+	priostr++;
+
+	/*
+	 * If the priostr points to NULL, we're at the end of the passed
+	 * in string, and its not a valid write
+	 */
+	if (*priostr == '\0')
+		goto out_free_devname;
+
+	ret = kstrtoul(priostr, 10, &priority);
+	if (ret < 0)
+		goto out_free_devname;
+
+	ret = -ENODEV;
+
+	dev = dev_get_by_name(&init_net, devname);
+	if (!dev)
+		goto out_free_devname;
+
+	update_netdev_tables();
+	ret = 0;
+	rcu_read_lock();
+	map = rcu_dereference(dev->priomap);
+	if (map)
+		map->priomap[prioidx] = priority;
+	rcu_read_unlock();
+	dev_put(dev);
+
+out_free_devname:
+	kfree(devname);
+	return ret;
+}
+
+static struct cftype ss_files[] = {
+	{
+		.name = "prioidx",
+		.read_u64 = read_prioidx,
+	},
+	{
+		.name = "ifpriomap",
+		.read_map = read_priomap,
+		.write_string = write_priomap,
+	},
+};
+
+static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
+{
+	return cgroup_add_files(cgrp, ss, ss_files, ARRAY_SIZE(ss_files));
+}
+
+static int netprio_device_event(struct notifier_block *unused,
+				unsigned long event, void *ptr)
+{
+	struct net_device *dev = ptr;
+	struct netprio_map *old;
+	u32 max_len = atomic_read(&max_prioidx);
+
+	/*
+	 * Note this is called with rtnl_lock held so we have update side
+	 * protection on our rcu assignments
+	 */
+
+	switch (event) {
+
+	case NETDEV_REGISTER:
+		if (max_len)
+			extend_netdev_table(dev, max_len);
+		break;
+	case NETDEV_UNREGISTER:
+		old = rtnl_dereference(dev->priomap);
+		RCU_INIT_POINTER(dev->priomap, NULL);
+		if (old)
+			kfree_rcu(old, rcu);
+		break;
+	}
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block netprio_device_notifier = {
+	.notifier_call = netprio_device_event
+};
+
+static int __init init_cgroup_netprio(void)
+{
+	int ret;
+
+	ret = cgroup_load_subsys(&net_prio_subsys);
+	if (ret)
+		goto out;
+#ifndef CONFIG_NETPRIO_CGROUP
+	smp_wmb();
+	net_prio_subsys_id = net_prio_subsys.subsys_id;
+#endif
+
+	register_netdevice_notifier(&netprio_device_notifier);
+
+out:
+	return ret;
+}
+
+static void __exit exit_cgroup_netprio(void)
+{
+	struct netprio_map *old;
+	struct net_device *dev;
+
+	unregister_netdevice_notifier(&netprio_device_notifier);
+
+	cgroup_unload_subsys(&net_prio_subsys);
+
+#ifndef CONFIG_NETPRIO_CGROUP
+	net_prio_subsys_id = -1;
+	synchronize_rcu();
+#endif
+
+	rtnl_lock();
+	for_each_netdev(&init_net, dev) {
+		old = rtnl_dereference(dev->priomap);
+		RCU_INIT_POINTER(dev->priomap, NULL);
+		if (old)
+			kfree_rcu(old, rcu);
+	}
+	rtnl_unlock();
+}
+
+module_init(init_cgroup_netprio);
+module_exit(exit_cgroup_netprio);
+MODULE_LICENSE("GPL v2");