[PATCH 5/7] netprio_cgroup: use cgroup->id instead of cgroup_netprio_state->prioidx

Tejun Heo
2012-11-20T08:30:39Z

With priomap expansion no longer depending on knowing max id
allocated, netprio_cgroup can use cgroup->id insted of cs->prioidx.
Drop prioidx alloc/free logic and convert all uses to cgroup->id.

* In cgrp_css_alloc(), parent->id test is moved above @cs allocation
to simplify error path.

* In cgrp_css_free(), @cs assignment is made initialization.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
---
include/net/netprio_cgroup.h | 11 +++-----
net/core/netprio_cgroup.c | 65 ++++++++------------------------------------
2 files changed, 15 insertions(+), 61 deletions(-)

diff --git a/include/net/netprio_cgroup.h b/include/net/netprio_cgroup.h
index 2760f4f..1d04b6f 100644
--- a/include/net/netprio_cgroup.h
+++ b/include/net/netprio_cgroup.h
@@ -27,7 +27,6 @@ struct netprio_map {

struct cgroup_netprio_state {
struct cgroup_subsys_state css;
- u32 prioidx;
};

extern void sock_update_netprioidx(struct sock *sk, struct task_struct *task);
@@ -36,13 +35,12 @@ extern void sock_update_netprioidx(struct sock *sk, struct task_struct *task);

static inline u32 task_netprioidx(struct task_struct *p)
{
- struct cgroup_netprio_state *state;
+ struct cgroup_subsys_state *css;
u32 idx;

rcu_read_lock();
- state = container_of(task_subsys_state(p, net_prio_subsys_id),
- struct cgroup_netprio_state, css);
- idx = state->prioidx;
+ css = task_subsys_state(p, net_prio_subsys_id);
+ idx = css->cgroup->id;
rcu_read_unlock();
return idx;
}
@@ -57,8 +55,7 @@ static inline u32 task_netprioidx(struct task_struct *p)
rcu_read_lock();
css = task_subsys_state(p, net_prio_subsys_id);
if (css)
- idx = container_of(css,
- struct cgroup_netprio_state, css)->prioidx;
+ idx = css->cgroup->id;
rcu_read_unlock();
return idx;
}
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index 569d83d..9409cdf 100644
--- a/net/core/netprio_cgroup.c
+++ b/net/core/netprio_cgroup.c
@@ -28,10 +28,6 @@
#include <linux/fdtable.h>

#define PRIOMAP_MIN_SZ 128
-#define PRIOIDX_SZ 128
-
-static unsigned long prioidx_map[PRIOIDX_SZ];
-static DEFINE_SPINLOCK(prioidx_map_lock);

static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgrp)
{
@@ -39,32 +35,6 @@ static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgr
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);
- if (prioidx == sizeof(unsigned long) * PRIOIDX_SZ) {
- spin_unlock_irqrestore(&prioidx_map_lock, flags);
- return -ENOSPC;
- }
- set_bit(prioidx, prioidx_map);
- spin_unlock_irqrestore(&prioidx_map_lock, flags);
- *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);
-}
-
/*
* Extend @dev->priomap so that it's large enough to accomodate
* @target_idx. @dev->priomap.priomap_len > @target_idx after successful
@@ -120,62 +90,50 @@ static int extend_netdev_table(struct net_device *dev, u32 target_idx)
static struct cgroup_subsys_state *cgrp_css_alloc(struct cgroup *cgrp)
{
struct cgroup_netprio_state *cs;
- int ret = -EINVAL;
+
+ if (cgrp->parent && cgrp->parent->id)
+ return ERR_PTR(-EINVAL);

cs = kzalloc(sizeof(*cs), GFP_KERNEL);
if (!cs)
return ERR_PTR(-ENOMEM);

- if (cgrp->parent && cgrp_netprio_state(cgrp->parent)->prioidx)
- goto out;
-
- ret = get_prioidx(&cs->prioidx);
- if (ret < 0) {
- pr_warn("No space in priority index array\n");
- goto out;
- }
-
return &cs->css;
-out:
- kfree(cs);
- return ERR_PTR(ret);
}

static void cgrp_css_free(struct cgroup *cgrp)
{
- struct cgroup_netprio_state *cs;
+ struct cgroup_netprio_state *cs = cgrp_netprio_state(cgrp);
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 && cs->prioidx < map->priomap_len)
- map->priomap[cs->prioidx] = 0;
+ if (map && cgrp->id < map->priomap_len)
+ map->priomap[cgrp->id] = 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;
+ return cgrp->id;
}

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 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 && prioidx < map->priomap_len) ? map->priomap[prioidx] : 0;
+ priority = (map && id < map->priomap_len) ? map->priomap[id] : 0;
cb->fill(cb, dev->name, priority);
}
rcu_read_unlock();
@@ -185,7 +143,6 @@ static int read_priomap(struct cgroup *cont, struct cftype *cft,
static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
const char *buffer)
{
- u32 prioidx = cgrp_netprio_state(cgrp)->prioidx;
char devname[IFNAMSIZ + 1];
struct net_device *dev;
struct netprio_map *map;
@@ -201,13 +158,13 @@ static int write_priomap(struct cgroup *cgrp, struct cftype *cft,

rtnl_lock();

- ret = extend_netdev_table(dev, prioidx);
+ ret = extend_netdev_table(dev, cgrp->id);
if (ret)
goto out_unlock;

map = rtnl_dereference(dev->priomap);
if (map)
- map->priomap[prioidx] = prio;
+ map->priomap[cgrp->id] = prio;
out_unlock:
rtnl_unlock();
dev_put(dev);
--
1.7.11.7