netprio_cgroup: pass around @css instead of @cgroup and kill struct cgroup_netprio_state

cgroup controller API will be converted to primarily use struct
cgroup_subsys_state instead of struct cgroup.  In preparation, make
the internal functions of netprio_cgroup pass around @css instead of
@cgrp.

While at it, kill struct cgroup_netprio_state which only contained
struct cgroup_subsys_state without serving any purpose.  All functions
are converted to deal with @css directly.

This patch shouldn't cause any behavior differences.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: David S. Miller <davem@davemloft.net>

2 files changed, 28 insertions, 32 deletions

diff --git a/include/net/netprio_cgroup.h b/include/net/netprio_cgroup.h
index 8110fa7ae60a..a24f8bb3ca47 100644
--- a/include/net/netprio_cgroup.h
+++ b/include/net/netprio_cgroup.h
@@ -25,10 +25,6 @@ struct netprio_map {
         u32 priomap[];
 };
 
-struct cgroup_netprio_state {
-        struct cgroup_subsys_state css;
-};
-
 extern void sock_update_netprioidx(struct sock *sk);
 
 #if IS_BUILTIN(CONFIG_NETPRIO_CGROUP)
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index ccf852311987..5dfac8886e12 100644
--- a/net/core/netprio_cgroup.c
+++ b/net/core/netprio_cgroup.c
@@ -29,12 +29,6 @@
 
 #define PRIOMAP_MIN_SZ          128
 
-static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgrp)
-{
-        return container_of(cgroup_css(cgrp, net_prio_subsys_id),
-                            struct cgroup_netprio_state, css);
-}
-
 /*
  * Extend @dev->priomap so that it's large enough to accomodate
  * @target_idx.  @dev->priomap.priomap_len > @target_idx after successful
@@ -87,68 +81,72 @@ static int extend_netdev_table(struct net_device *dev, u32 target_idx)
 
 /**
  * netprio_prio - return the effective netprio of a cgroup-net_device pair
- * @cgrp: cgroup part of the target pair
+ * @css: css 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)
+static u32 netprio_prio(struct cgroup_subsys_state *css, struct net_device *dev)
 {
         struct netprio_map *map = rcu_dereference_rtnl(dev->priomap);
+        int id = css->cgroup->id;
 
-        if (map && cgrp->id < map->priomap_len)
-                return map->priomap[cgrp->id];
+        if (map && id < map->priomap_len)
+                return map->priomap[id];
         return 0;
 }
 
 /**
  * netprio_set_prio - set netprio on a cgroup-net_device pair
- * @cgrp: cgroup part of the target pair
+ * @css: css 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
+ * Set netprio to @prio on @css-@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)
+static int netprio_set_prio(struct cgroup_subsys_state *css,
+                            struct net_device *dev, u32 prio)
 {
         struct netprio_map *map;
+        int id = css->cgroup->id;
         int ret;
 
         /* avoid extending priomap for zero writes */
         map = rtnl_dereference(dev->priomap);
-        if (!prio && (!map || map->priomap_len <= cgrp->id))
+        if (!prio && (!map || map->priomap_len <= id))
                 return 0;
 
-        ret = extend_netdev_table(dev, cgrp->id);
+        ret = extend_netdev_table(dev, id);
         if (ret)
                 return ret;
 
         map = rtnl_dereference(dev->priomap);
-        map->priomap[cgrp->id] = prio;
+        map->priomap[id] = prio;
         return 0;
 }
 
 static struct cgroup_subsys_state *cgrp_css_alloc(struct cgroup *cgrp)
 {
-        struct cgroup_netprio_state *cs;
+        struct cgroup_subsys_state *css;
 
-        cs = kzalloc(sizeof(*cs), GFP_KERNEL);
-        if (!cs)
+        css = kzalloc(sizeof(*css), GFP_KERNEL);
+        if (!css)
                 return ERR_PTR(-ENOMEM);
 
-        return &cs->css;
+        return css;
 }
 
 static int cgrp_css_online(struct cgroup *cgrp)
 {
-        struct cgroup *parent = cgrp->parent;
+        struct cgroup_subsys_state *css = cgroup_css(cgrp, net_prio_subsys_id);
+        struct cgroup_subsys_state *parent_css;
         struct net_device *dev;
         int ret = 0;
 
-        if (!parent)
+        if (!cgrp->parent)
                 return 0;
+        parent_css = cgroup_css(cgrp->parent, net_prio_subsys_id);
 
         rtnl_lock();
         /*
@@ -156,9 +154,9 @@ static int cgrp_css_online(struct cgroup *cgrp)
          * onlining, there is no need to clear them on offline.
          */
         for_each_netdev(&init_net, dev) {
-                u32 prio = netprio_prio(parent, dev);
+                u32 prio = netprio_prio(parent_css, dev);
 
-                ret = netprio_set_prio(cgrp, dev, prio);
+                ret = netprio_set_prio(css, dev, prio);
                 if (ret)
                         break;
         }
@@ -168,7 +166,7 @@ static int cgrp_css_online(struct cgroup *cgrp)
 
 static void cgrp_css_free(struct cgroup *cgrp)
 {
-        kfree(cgrp_netprio_state(cgrp));
+        kfree(cgroup_css(cgrp, net_prio_subsys_id));
 }
 
 static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft)
@@ -179,11 +177,12 @@ static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft)
 static int read_priomap(struct cgroup *cont, struct cftype *cft,
                         struct cgroup_map_cb *cb)
 {
+        struct cgroup_subsys_state *css = cgroup_css(cont, net_prio_subsys_id);
         struct net_device *dev;
 
         rcu_read_lock();
         for_each_netdev_rcu(&init_net, dev)
-                cb->fill(cb, dev->name, netprio_prio(cont, dev));
+                cb->fill(cb, dev->name, netprio_prio(css, dev));
         rcu_read_unlock();
         return 0;
 }
@@ -191,6 +190,7 @@ static int read_priomap(struct cgroup *cont, struct cftype *cft,
 static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
                          const char *buffer)
 {
+        struct cgroup_subsys_state *css = cgroup_css(cgrp, net_prio_subsys_id);
         char devname[IFNAMSIZ + 1];
         struct net_device *dev;
         u32 prio;
@@ -205,7 +205,7 @@ static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
 
         rtnl_lock();
 
-        ret = netprio_set_prio(cgrp, dev, prio);
+        ret = netprio_set_prio(css, dev, prio);
 
         rtnl_unlock();
         dev_put(dev);