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Commit 666b0ebe authored by Tejun Heo's avatar Tejun Heo
Browse files

netprio_cgroup: implement netprio[_set]_prio() helpers 



Introduce two helpers - netprio_prio() and netprio_set_prio() - which
hide the details of priomap access and expansion.  This will help
implementing hierarchy support.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarNeil Horman <nhorman@tuxdriver.com>
Tested-and-Acked-by: default avatarDaniel Wagner <daniel.wagner@bmw-carit.de>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 88d642fa

net/core/netprio_cgroup.c

+50 −22
Original line number Diff line number Diff line
@@ -87,6 +87,51 @@ static int extend_netdev_table(struct net_device *dev, u32 target_idx) 
	return 0;

}



/**

 * netprio_prio - return the effective netprio of a cgroup-net_device pair

 * @cgrp: cgroup part of the target pair

 * @dev: net_device part of the target pair

 *

 * Should be called under RCU read or rtnl lock.

 */

static u32 netprio_prio(struct cgroup *cgrp, struct net_device *dev)

{

	struct netprio_map *map = rcu_dereference_rtnl(dev->priomap);



	if (map && cgrp->id < map->priomap_len)

		return map->priomap[cgrp->id];

	return 0;

}



/**

 * netprio_set_prio - set netprio on a cgroup-net_device pair

 * @cgrp: cgroup part of the target pair

 * @dev: net_device part of the target pair

 * @prio: prio to set

 *

 * Set netprio to @prio on @cgrp-@dev pair.  Should be called under rtnl

 * lock and may fail under memory pressure for non-zero @prio.

 */

static int netprio_set_prio(struct cgroup *cgrp, struct net_device *dev,

			    u32 prio)

{

	struct netprio_map *map;

	int ret;



	/* avoid extending priomap for zero writes */

	map = rtnl_dereference(dev->priomap);

	if (!prio && (!map || map->priomap_len <= cgrp->id))

		return 0;



	ret = extend_netdev_table(dev, cgrp->id);

	if (ret)

		return ret;



	map = rtnl_dereference(dev->priomap);

	map->priomap[cgrp->id] = prio;

	return 0;

}



static struct cgroup_subsys_state *cgrp_css_alloc(struct cgroup *cgrp)

{

	struct cgroup_netprio_state *cs;
@@ -105,14 +150,10 @@ static void cgrp_css_free(struct cgroup *cgrp) 
{

	struct cgroup_netprio_state *cs = cgrp_netprio_state(cgrp);

	struct net_device *dev;

	struct netprio_map *map;



	rtnl_lock();

	for_each_netdev(&init_net, dev) {

		map = rtnl_dereference(dev->priomap);

		if (map && cgrp->id < map->priomap_len)

			map->priomap[cgrp->id] = 0;

	}

	for_each_netdev(&init_net, dev)

		WARN_ON_ONCE(netprio_set_prio(cgrp, dev, 0));

	rtnl_unlock();

	kfree(cs);

}
@@ -126,16 +167,10 @@ static int read_priomap(struct cgroup *cont, struct cftype *cft, 
			struct cgroup_map_cb *cb)

{

	struct net_device *dev;

	u32 id = cont->id;

	u32 priority;

	struct netprio_map *map;



	rcu_read_lock();

	for_each_netdev_rcu(&init_net, dev) {

		map = rcu_dereference(dev->priomap);

		priority = (map && id < map->priomap_len) ? map->priomap[id] : 0;

		cb->fill(cb, dev->name, priority);

	}

	for_each_netdev_rcu(&init_net, dev)

		cb->fill(cb, dev->name, netprio_prio(cont, dev));

	rcu_read_unlock();

	return 0;

}
@@ -145,7 +180,6 @@ static int write_priomap(struct cgroup *cgrp, struct cftype *cft, 
{

	char devname[IFNAMSIZ + 1];

	struct net_device *dev;

	struct netprio_map *map;

	u32 prio;

	int ret;
@@ -158,14 +192,8 @@ static int write_priomap(struct cgroup *cgrp, struct cftype *cft, 


	rtnl_lock();



	ret = extend_netdev_table(dev, cgrp->id);

	if (ret)

		goto out_unlock;

	ret = netprio_set_prio(cgrp, dev, prio);



	map = rtnl_dereference(dev->priomap);

	if (map)

		map->priomap[cgrp->id] = prio;

out_unlock:

	rtnl_unlock();

	dev_put(dev);

	return ret;