Merge branch 'for-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup updates from Tejun Heo:
 "A lot of activities on the cgroup front.  Most changes aren't visible
  to userland at all at this point and are laying foundation for the
  planned unified hierarchy.

   - The biggest change is decoupling the lifetime management of css
     (cgroup_subsys_state) from that of cgroup's.  Because controllers
     (cpu, memory, block and so on) will need to be dynamically enabled
     and disabled, css which is the association point between a cgroup
     and a controller may come and go dynamically across the lifetime of
     a cgroup.  Till now, css's were created when the associated cgroup
     was created and stayed till the cgroup got destroyed.

     Assumptions around this tight coupling permeated through cgroup
     core and controllers.  These assumptions are gradually removed,
     which consists bulk of patches, and css destruction path is
     completely decoupled from cgroup destruction path.  Note that
     decoupling of creation path is relatively easy on top of these
     changes and the patchset is pending for the next window.

   - cgroup has its own event mechanism cgroup.event_control, which is
     only used by memcg.  It is overly complex trying to achieve high
     flexibility whose benefits seem dubious at best.  Going forward,
     new events will simply generate file modified event and the
     existing mechanism is being made specific to memcg.  This pull
     request contains prepatory patches for such change.

   - Various fixes and cleanups"

Fixed up conflict in kernel/cgroup.c as per Tejun.

* 'for-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (69 commits)
  cgroup: fix cgroup_css() invocation in css_from_id()
  cgroup: make cgroup_write_event_control() use css_from_dir() instead of __d_cgrp()
  cgroup: make cgroup_event hold onto cgroup_subsys_state instead of cgroup
  cgroup: implement CFTYPE_NO_PREFIX
  cgroup: make cgroup_css() take cgroup_subsys * instead and allow NULL subsys
  cgroup: rename cgroup_css_from_dir() to css_from_dir() and update its syntax
  cgroup: fix cgroup_write_event_control()
  cgroup: fix subsystem file accesses on the root cgroup
  cgroup: change cgroup_from_id() to css_from_id()
  cgroup: use css_get() in cgroup_create() to check CSS_ROOT
  cpuset: remove an unncessary forward declaration
  cgroup: RCU protect each cgroup_subsys_state release
  cgroup: move subsys file removal to kill_css()
  cgroup: factor out kill_css()
  cgroup: decouple cgroup_subsys_state destruction from cgroup destruction
  cgroup: replace cgroup->css_kill_cnt with ->nr_css
  cgroup: bounce cgroup_subsys_state ref kill confirmation to a work item
  cgroup: move cgroup->subsys[] assignment to online_css()
  cgroup: reorganize css init / exit paths
  cgroup: add __rcu modifier to cgroup->subsys[]
  ...

1 files changed, 21 insertions, 18 deletions

diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c
index 3a294eb98d61..867b4a3e3980 100644
--- a/net/sched/cls_cgroup.c
+++ b/net/sched/cls_cgroup.c
@@ -23,19 +23,18 @@
 #include <net/sock.h>
 #include <net/cls_cgroup.h>
 
-static inline struct cgroup_cls_state *cgrp_cls_state(struct cgroup *cgrp)
+static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state *css)
 {
-	return container_of(cgroup_subsys_state(cgrp, net_cls_subsys_id),
-			    struct cgroup_cls_state, css);
+	return css ? container_of(css, struct cgroup_cls_state, css) : NULL;
 }
 
 static inline struct cgroup_cls_state *task_cls_state(struct task_struct *p)
 {
-	return container_of(task_subsys_state(p, net_cls_subsys_id),
-			    struct cgroup_cls_state, css);
+	return css_cls_state(task_css(p, net_cls_subsys_id));
 }
 
-static struct cgroup_subsys_state *cgrp_css_alloc(struct cgroup *cgrp)
+static struct cgroup_subsys_state *
+cgrp_css_alloc(struct cgroup_subsys_state *parent_css)
 {
 	struct cgroup_cls_state *cs;
 
@@ -45,17 +44,19 @@ static struct cgroup_subsys_state *cgrp_css_alloc(struct cgroup *cgrp)
 	return &cs->css;
 }
 
-static int cgrp_css_online(struct cgroup *cgrp)
+static int cgrp_css_online(struct cgroup_subsys_state *css)
 {
-	if (cgrp->parent)
-		cgrp_cls_state(cgrp)->classid =
-			cgrp_cls_state(cgrp->parent)->classid;
+	struct cgroup_cls_state *cs = css_cls_state(css);
+	struct cgroup_cls_state *parent = css_cls_state(css_parent(css));
+
+	if (parent)
+		cs->classid = parent->classid;
 	return 0;
 }
 
-static void cgrp_css_free(struct cgroup *cgrp)
+static void cgrp_css_free(struct cgroup_subsys_state *css)
 {
-	kfree(cgrp_cls_state(cgrp));
+	kfree(css_cls_state(css));
 }
 
 static int update_classid(const void *v, struct file *file, unsigned n)
@@ -67,12 +68,13 @@ static int update_classid(const void *v, struct file *file, unsigned n)
 	return 0;
 }
 
-static void cgrp_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
+static void cgrp_attach(struct cgroup_subsys_state *css,
+			struct cgroup_taskset *tset)
 {
 	struct task_struct *p;
 	void *v;
 
-	cgroup_taskset_for_each(p, cgrp, tset) {
+	cgroup_taskset_for_each(p, css, tset) {
 		task_lock(p);
 		v = (void *)(unsigned long)task_cls_classid(p);
 		iterate_fd(p->files, 0, update_classid, v);
@@ -80,14 +82,15 @@ static void cgrp_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
 	}
 }
 
-static u64 read_classid(struct cgroup *cgrp, struct cftype *cft)
+static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
 {
-	return cgrp_cls_state(cgrp)->classid;
+	return css_cls_state(css)->classid;
 }
 
-static int write_classid(struct cgroup *cgrp, struct cftype *cft, u64 value)
+static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
+			 u64 value)
 {
-	cgrp_cls_state(cgrp)->classid = (u32) value;
+	css_cls_state(css)->classid = (u32) value;
 	return 0;
 }