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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: Tejun Heo <tj@kernel.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Tested-and-Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Acked-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tejun Heo 2012-11-22 07:32:47 -08:00
parent 88d642fa2c
commit 666b0ebe2b
1 changed files with 50 additions and 22 deletions
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72
net/core/netprio_cgroup.c
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@ -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;