netprio_cgroup: use cgroup->id instead of cgroup_netprio_state->prioidx

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>
Tested-and-Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Acked-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/netprio_cgroup.h b/include/net/netprio_cgroup.h
index 2760f4f..1d04b6f 100644 (file)
--- 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 (file)
--- 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);