diff options
author | Tejun Heo <tj@kernel.org> | 2012-11-22 15:32:47 (GMT) |
---|---|---|
committer | Tejun Heo <tj@kernel.org> | 2012-11-22 15:32:47 (GMT) |
commit | 666b0ebe2b04e69583c279becf27a653ba4a894c (patch) | |
tree | 75e8408458bf99f7e052035e812d0ffcd69e48fa /net/core | |
parent | 88d642fa2ce87c125b84cfcf23c371618d8b08b4 (diff) | |
download | linux-666b0ebe2b04e69583c279becf27a653ba4a894c.tar.xz |
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>
Diffstat (limited to 'net/core')
-rw-r--r-- | net/core/netprio_cgroup.c | 72 |
1 files changed, 50 insertions, 22 deletions
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c index 9409cdf..b2af0d0 100644 --- a/net/core/netprio_cgroup.c +++ b/net/core/netprio_cgroup.c @@ -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; |