1 files changed, 355 insertions, 267 deletions

diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index e7bebb7c6c3..a79e40f9d70 100644
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -14,383 +14,471 @@
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  */
 
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/slab.h>
 #include <linux/cgroup.h>
 #include <linux/fs.h>
 #include <linux/uaccess.h>
 #include <linux/freezer.h>
 #include <linux/seq_file.h>
+#include <linux/mutex.h>
 
-enum freezer_state {
-	CGROUP_THAWED = 0,
-	CGROUP_FREEZING,
-	CGROUP_FROZEN,
+/*
+ * A cgroup is freezing if any FREEZING flags are set.  FREEZING_SELF is
+ * set if "FROZEN" is written to freezer.state cgroupfs file, and cleared
+ * for "THAWED".  FREEZING_PARENT is set if the parent freezer is FREEZING
+ * for whatever reason.  IOW, a cgroup has FREEZING_PARENT set if one of
+ * its ancestors has FREEZING_SELF set.
+ */
+enum freezer_state_flags {
+	CGROUP_FREEZER_ONLINE	= (1 << 0), /* freezer is fully online */
+	CGROUP_FREEZING_SELF	= (1 << 1), /* this freezer is freezing */
+	CGROUP_FREEZING_PARENT	= (1 << 2), /* the parent freezer is freezing */
+	CGROUP_FROZEN		= (1 << 3), /* this and its descendants frozen */
+
+	/* mask for all FREEZING flags */
+	CGROUP_FREEZING		= CGROUP_FREEZING_SELF | CGROUP_FREEZING_PARENT,
 };
 
 struct freezer {
-	struct cgroup_subsys_state css;
-	enum freezer_state state;
-	spinlock_t lock; /* protects _writes_ to state */
+	struct cgroup_subsys_state	css;
+	unsigned int			state;
 };
 
-static inline struct freezer *cgroup_freezer(
-		struct cgroup *cgroup)
+static DEFINE_MUTEX(freezer_mutex);
+
+static inline struct freezer *css_freezer(struct cgroup_subsys_state *css)
 {
-	return container_of(
-		cgroup_subsys_state(cgroup, freezer_subsys_id),
-		struct freezer, css);
+	return css ? container_of(css, struct freezer, css) : NULL;
 }
 
 static inline struct freezer *task_freezer(struct task_struct *task)
 {
-	return container_of(task_subsys_state(task, freezer_subsys_id),
-			    struct freezer, css);
+	return css_freezer(task_css(task, freezer_cgrp_id));
 }
 
-static inline int __cgroup_freezing_or_frozen(struct task_struct *task)
+static struct freezer *parent_freezer(struct freezer *freezer)
 {
-	enum freezer_state state = task_freezer(task)->state;
-	return (state == CGROUP_FREEZING) || (state == CGROUP_FROZEN);
+	return css_freezer(freezer->css.parent);
 }
 
-int cgroup_freezing_or_frozen(struct task_struct *task)
+bool cgroup_freezing(struct task_struct *task)
 {
-	int result;
-	task_lock(task);
-	result = __cgroup_freezing_or_frozen(task);
-	task_unlock(task);
-	return result;
+	bool ret;
+
+	rcu_read_lock();
+	ret = task_freezer(task)->state & CGROUP_FREEZING;
+	rcu_read_unlock();
+
+	return ret;
 }
 
-/*
- * cgroups_write_string() limits the size of freezer state strings to
- * CGROUP_LOCAL_BUFFER_SIZE
- */
-static const char *freezer_state_strs[] = {
-	"THAWED",
-	"FREEZING",
-	"FROZEN",
+static const char *freezer_state_strs(unsigned int state)
+{
+	if (state & CGROUP_FROZEN)
+		return "FROZEN";
+	if (state & CGROUP_FREEZING)
+		return "FREEZING";
+	return "THAWED";
 };
 
-/*
- * State diagram
- * Transitions are caused by userspace writes to the freezer.state file.
- * The values in parenthesis are state labels. The rest are edge labels.
+static struct cgroup_subsys_state *
+freezer_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+	struct freezer *freezer;
+
+	freezer = kzalloc(sizeof(struct freezer), GFP_KERNEL);
+	if (!freezer)
+		return ERR_PTR(-ENOMEM);
+
+	return &freezer->css;
+}
+
+/**
+ * freezer_css_online - commit creation of a freezer css
+ * @css: css being created
  *
- * (THAWED) --FROZEN--> (FREEZING) --FROZEN--> (FROZEN)
- *    ^ ^                    |                     |
- *    | \_______THAWED_______/                     |
- *    \__________________________THAWED____________/
+ * We're committing to creation of @css.  Mark it online and inherit
+ * parent's freezing state while holding both parent's and our
+ * freezer->lock.
  */
+static int freezer_css_online(struct cgroup_subsys_state *css)
+{
+	struct freezer *freezer = css_freezer(css);
+	struct freezer *parent = parent_freezer(freezer);
 
-struct cgroup_subsys freezer_subsys;
+	mutex_lock(&freezer_mutex);
 
-/* Locks taken and their ordering
- * ------------------------------
- * cgroup_mutex (AKA cgroup_lock)
- * freezer->lock
- * css_set_lock
- * task->alloc_lock (AKA task_lock)
- * task->sighand->siglock
- *
- * cgroup code forces css_set_lock to be taken before task->alloc_lock
- *
- * freezer_create(), freezer_destroy():
- * cgroup_mutex [ by cgroup core ]
- *
- * freezer_can_attach():
- * cgroup_mutex (held by caller of can_attach)
- *
- * cgroup_freezing_or_frozen():
- * task->alloc_lock (to get task's cgroup)
- *
- * freezer_fork() (preserving fork() performance means can't take cgroup_mutex):
- * freezer->lock
- *  sighand->siglock (if the cgroup is freezing)
- *
- * freezer_read():
- * cgroup_mutex
- *  freezer->lock
- *   write_lock css_set_lock (cgroup iterator start)
- *    task->alloc_lock
- *   read_lock css_set_lock (cgroup iterator start)
- *
- * freezer_write() (freeze):
- * cgroup_mutex
- *  freezer->lock
- *   write_lock css_set_lock (cgroup iterator start)
- *    task->alloc_lock
- *   read_lock css_set_lock (cgroup iterator start)
- *    sighand->siglock (fake signal delivery inside freeze_task())
+	freezer->state |= CGROUP_FREEZER_ONLINE;
+
+	if (parent && (parent->state & CGROUP_FREEZING)) {
+		freezer->state |= CGROUP_FREEZING_PARENT | CGROUP_FROZEN;
+		atomic_inc(&system_freezing_cnt);
+	}
+
+	mutex_unlock(&freezer_mutex);
+	return 0;
+}
+
+/**
+ * freezer_css_offline - initiate destruction of a freezer css
+ * @css: css being destroyed
  *
- * freezer_write() (unfreeze):
- * cgroup_mutex
- *  freezer->lock
- *   write_lock css_set_lock (cgroup iterator start)
- *    task->alloc_lock
- *   read_lock css_set_lock (cgroup iterator start)
- *    task->alloc_lock (inside thaw_process(), prevents race with refrigerator())
- *     sighand->siglock
+ * @css is going away.  Mark it dead and decrement system_freezing_count if
+ * it was holding one.
  */
-static struct cgroup_subsys_state *freezer_create(struct cgroup_subsys *ss,
-						  struct cgroup *cgroup)
+static void freezer_css_offline(struct cgroup_subsys_state *css)
 {
-	struct freezer *freezer;
+	struct freezer *freezer = css_freezer(css);
 
-	freezer = kzalloc(sizeof(struct freezer), GFP_KERNEL);
-	if (!freezer)
-		return ERR_PTR(-ENOMEM);
+	mutex_lock(&freezer_mutex);
 
-	spin_lock_init(&freezer->lock);
-	freezer->state = CGROUP_THAWED;
-	return &freezer->css;
+	if (freezer->state & CGROUP_FREEZING)
+		atomic_dec(&system_freezing_cnt);
+
+	freezer->state = 0;
+
+	mutex_unlock(&freezer_mutex);
 }
 
-static void freezer_destroy(struct cgroup_subsys *ss,
-			    struct cgroup *cgroup)
+static void freezer_css_free(struct cgroup_subsys_state *css)
 {
-	kfree(cgroup_freezer(cgroup));
+	kfree(css_freezer(css));
 }
 
 /*
- * The call to cgroup_lock() in the freezer.state write method prevents
- * a write to that file racing against an attach, and hence the
- * can_attach() result will remain valid until the attach completes.
+ * Tasks can be migrated into a different freezer anytime regardless of its
+ * current state.  freezer_attach() is responsible for making new tasks
+ * conform to the current state.
+ *
+ * Freezer state changes and task migration are synchronized via
+ * @freezer->lock.  freezer_attach() makes the new tasks conform to the
+ * current state and all following state changes can see the new tasks.
  */
-static int freezer_can_attach(struct cgroup_subsys *ss,
-			      struct cgroup *new_cgroup,
-			      struct task_struct *task, bool threadgroup)
+static void freezer_attach(struct cgroup_subsys_state *new_css,
+			   struct cgroup_taskset *tset)
 {
-	struct freezer *freezer;
+	struct freezer *freezer = css_freezer(new_css);
+	struct task_struct *task;
+	bool clear_frozen = false;
+
+	mutex_lock(&freezer_mutex);
 
 	/*
-	 * Anything frozen can't move or be moved to/from.
+	 * Make the new tasks conform to the current state of @new_css.
+	 * For simplicity, when migrating any task to a FROZEN cgroup, we
+	 * revert it to FREEZING and let update_if_frozen() determine the
+	 * correct state later.
+	 *
+	 * Tasks in @tset are on @new_css but may not conform to its
+	 * current state before executing the following - !frozen tasks may
+	 * be visible in a FROZEN cgroup and frozen tasks in a THAWED one.
 	 */
-
-	freezer = cgroup_freezer(new_cgroup);
-	if (freezer->state != CGROUP_THAWED)
-		return -EBUSY;
-
-	rcu_read_lock();
-	if (__cgroup_freezing_or_frozen(task)) {
-		rcu_read_unlock();
-		return -EBUSY;
+	cgroup_taskset_for_each(task, tset) {
+		if (!(freezer->state & CGROUP_FREEZING)) {
+			__thaw_task(task);
+		} else {
+			freeze_task(task);
+			freezer->state &= ~CGROUP_FROZEN;
+			clear_frozen = true;
+		}
 	}
-	rcu_read_unlock();
-
-	if (threadgroup) {
-		struct task_struct *c;
 
-		rcu_read_lock();
-		list_for_each_entry_rcu(c, &task->thread_group, thread_group) {
-			if (__cgroup_freezing_or_frozen(c)) {
-				rcu_read_unlock();
-				return -EBUSY;
-			}
-		}
-		rcu_read_unlock();
+	/* propagate FROZEN clearing upwards */
+	while (clear_frozen && (freezer = parent_freezer(freezer))) {
+		freezer->state &= ~CGROUP_FROZEN;
+		clear_frozen = freezer->state & CGROUP_FREEZING;
 	}
 
-	return 0;
+	mutex_unlock(&freezer_mutex);
 }
 
-static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
+/**
+ * freezer_fork - cgroup post fork callback
+ * @task: a task which has just been forked
+ *
+ * @task has just been created and should conform to the current state of
+ * the cgroup_freezer it belongs to.  This function may race against
+ * freezer_attach().  Losing to freezer_attach() means that we don't have
+ * to do anything as freezer_attach() will put @task into the appropriate
+ * state.
+ */
+static void freezer_fork(struct task_struct *task)
 {
 	struct freezer *freezer;
 
 	/*
-	 * No lock is needed, since the task isn't on tasklist yet,
-	 * so it can't be moved to another cgroup, which means the
-	 * freezer won't be removed and will be valid during this
-	 * function call.  Nevertheless, apply RCU read-side critical
-	 * section to suppress RCU lockdep false positives.
+	 * The root cgroup is non-freezable, so we can skip locking the
+	 * freezer.  This is safe regardless of race with task migration.
+	 * If we didn't race or won, skipping is obviously the right thing
+	 * to do.  If we lost and root is the new cgroup, noop is still the
+	 * right thing to do.
 	 */
-	rcu_read_lock();
-	freezer = task_freezer(task);
-	rcu_read_unlock();
-
-	/*
-	 * The root cgroup is non-freezable, so we can skip the
-	 * following check.
-	 */
-	if (!freezer->css.cgroup->parent)
+	if (task_css_is_root(task, freezer_cgrp_id))
 		return;
 
-	spin_lock_irq(&freezer->lock);
-	BUG_ON(freezer->state == CGROUP_FROZEN);
+	mutex_lock(&freezer_mutex);
+	rcu_read_lock();
+
+	freezer = task_freezer(task);
+	if (freezer->state & CGROUP_FREEZING)
+		freeze_task(task);
 
-	/* Locking avoids race with FREEZING -> THAWED transitions. */
-	if (freezer->state == CGROUP_FREEZING)
-		freeze_task(task, true);
-	spin_unlock_irq(&freezer->lock);
+	rcu_read_unlock();
+	mutex_unlock(&freezer_mutex);
 }
 
-/*
- * caller must hold freezer->lock
+/**
+ * update_if_frozen - update whether a cgroup finished freezing
+ * @css: css of interest
+ *
+ * Once FREEZING is initiated, transition to FROZEN is lazily updated by
+ * calling this function.  If the current state is FREEZING but not FROZEN,
+ * this function checks whether all tasks of this cgroup and the descendant
+ * cgroups finished freezing and, if so, sets FROZEN.
+ *
+ * The caller is responsible for grabbing RCU read lock and calling
+ * update_if_frozen() on all descendants prior to invoking this function.
+ *
+ * Task states and freezer state might disagree while tasks are being
+ * migrated into or out of @css, so we can't verify task states against
+ * @freezer state here.  See freezer_attach() for details.
  */
-static void update_if_frozen(struct cgroup *cgroup,
-				 struct freezer *freezer)
+static void update_if_frozen(struct cgroup_subsys_state *css)
 {
-	struct cgroup_iter it;
+	struct freezer *freezer = css_freezer(css);
+	struct cgroup_subsys_state *pos;
+	struct css_task_iter it;
 	struct task_struct *task;
-	unsigned int nfrozen = 0, ntotal = 0;
-	enum freezer_state old_state = freezer->state;
-
-	cgroup_iter_start(cgroup, &it);
-	while ((task = cgroup_iter_next(cgroup, &it))) {
-		ntotal++;
-		if (frozen(task))
-			nfrozen++;
+
+	lockdep_assert_held(&freezer_mutex);
+
+	if (!(freezer->state & CGROUP_FREEZING) ||
+	    (freezer->state & CGROUP_FROZEN))
+		return;
+
+	/* are all (live) children frozen? */
+	rcu_read_lock();
+	css_for_each_child(pos, css) {
+		struct freezer *child = css_freezer(pos);
+
+		if ((child->state & CGROUP_FREEZER_ONLINE) &&
+		    !(child->state & CGROUP_FROZEN)) {
+			rcu_read_unlock();
+			return;
+		}
 	}
+	rcu_read_unlock();
 
-	if (old_state == CGROUP_THAWED) {
-		BUG_ON(nfrozen > 0);
-	} else if (old_state == CGROUP_FREEZING) {
-		if (nfrozen == ntotal)
-			freezer->state = CGROUP_FROZEN;
-	} else { /* old_state == CGROUP_FROZEN */
-		BUG_ON(nfrozen != ntotal);
+	/* are all tasks frozen? */
+	css_task_iter_start(css, &it);
+
+	while ((task = css_task_iter_next(&it))) {
+		if (freezing(task)) {
+			/*
+			 * freezer_should_skip() indicates that the task
+			 * should be skipped when determining freezing
+			 * completion.  Consider it frozen in addition to
+			 * the usual frozen condition.
+			 */
+			if (!frozen(task) && !freezer_should_skip(task))
+				goto out_iter_end;
+		}
 	}
 
-	cgroup_iter_end(cgroup, &it);
+	freezer->state |= CGROUP_FROZEN;
+out_iter_end:
+	css_task_iter_end(&it);
 }
 
-static int freezer_read(struct cgroup *cgroup, struct cftype *cft,
-			struct seq_file *m)
+static int freezer_read(struct seq_file *m, void *v)
 {
-	struct freezer *freezer;
-	enum freezer_state state;
-
-	if (!cgroup_lock_live_group(cgroup))
-		return -ENODEV;
-
-	freezer = cgroup_freezer(cgroup);
-	spin_lock_irq(&freezer->lock);
-	state = freezer->state;
-	if (state == CGROUP_FREEZING) {
-		/* We change from FREEZING to FROZEN lazily if the cgroup was
-		 * only partially frozen when we exitted write. */
-		update_if_frozen(cgroup, freezer);
-		state = freezer->state;
+	struct cgroup_subsys_state *css = seq_css(m), *pos;
+
+	mutex_lock(&freezer_mutex);
+	rcu_read_lock();
+
+	/* update states bottom-up */
+	css_for_each_descendant_post(pos, css) {
+		if (!css_tryget_online(pos))
+			continue;
+		rcu_read_unlock();
+
+		update_if_frozen(pos);
+
+		rcu_read_lock();
+		css_put(pos);
 	}
-	spin_unlock_irq(&freezer->lock);
-	cgroup_unlock();
 
-	seq_puts(m, freezer_state_strs[state]);
+	rcu_read_unlock();
+	mutex_unlock(&freezer_mutex);
+
+	seq_puts(m, freezer_state_strs(css_freezer(css)->state));
 	seq_putc(m, '\n');
 	return 0;
 }
 
-static int try_to_freeze_cgroup(struct cgroup *cgroup, struct freezer *freezer)
+static void freeze_cgroup(struct freezer *freezer)
 {
-	struct cgroup_iter it;
+	struct css_task_iter it;
 	struct task_struct *task;
-	unsigned int num_cant_freeze_now = 0;
 
-	freezer->state = CGROUP_FREEZING;
-	cgroup_iter_start(cgroup, &it);
-	while ((task = cgroup_iter_next(cgroup, &it))) {
-		if (!freeze_task(task, true))
-			continue;
-		if (frozen(task))
-			continue;
-		if (!freezing(task) && !freezer_should_skip(task))
-			num_cant_freeze_now++;
-	}
-	cgroup_iter_end(cgroup, &it);
-
-	return num_cant_freeze_now ? -EBUSY : 0;
+	css_task_iter_start(&freezer->css, &it);
+	while ((task = css_task_iter_next(&it)))
+		freeze_task(task);
+	css_task_iter_end(&it);
 }
 
-static void unfreeze_cgroup(struct cgroup *cgroup, struct freezer *freezer)
+static void unfreeze_cgroup(struct freezer *freezer)
 {
-	struct cgroup_iter it;
+	struct css_task_iter it;
 	struct task_struct *task;
 
-	cgroup_iter_start(cgroup, &it);
-	while ((task = cgroup_iter_next(cgroup, &it))) {
-		thaw_process(task);
-	}
-	cgroup_iter_end(cgroup, &it);
+	css_task_iter_start(&freezer->css, &it);
+	while ((task = css_task_iter_next(&it)))
+		__thaw_task(task);
+	css_task_iter_end(&it);
+}
 
-	freezer->state = CGROUP_THAWED;
+/**
+ * freezer_apply_state - apply state change to a single cgroup_freezer
+ * @freezer: freezer to apply state change to
+ * @freeze: whether to freeze or unfreeze
+ * @state: CGROUP_FREEZING_* flag to set or clear
+ *
+ * Set or clear @state on @cgroup according to @freeze, and perform
+ * freezing or thawing as necessary.
+ */
+static void freezer_apply_state(struct freezer *freezer, bool freeze,
+				unsigned int state)
+{
+	/* also synchronizes against task migration, see freezer_attach() */
+	lockdep_assert_held(&freezer_mutex);
+
+	if (!(freezer->state & CGROUP_FREEZER_ONLINE))
+		return;
+
+	if (freeze) {
+		if (!(freezer->state & CGROUP_FREEZING))
+			atomic_inc(&system_freezing_cnt);
+		freezer->state |= state;
+		freeze_cgroup(freezer);
+	} else {
+		bool was_freezing = freezer->state & CGROUP_FREEZING;
+
+		freezer->state &= ~state;
+
+		if (!(freezer->state & CGROUP_FREEZING)) {
+			if (was_freezing)
+				atomic_dec(&system_freezing_cnt);
+			freezer->state &= ~CGROUP_FROZEN;
+			unfreeze_cgroup(freezer);
+		}
+	}
 }
 
-static int freezer_change_state(struct cgroup *cgroup,
-				enum freezer_state goal_state)
+/**
+ * freezer_change_state - change the freezing state of a cgroup_freezer
+ * @freezer: freezer of interest
+ * @freeze: whether to freeze or thaw
+ *
+ * Freeze or thaw @freezer according to @freeze.  The operations are
+ * recursive - all descendants of @freezer will be affected.
+ */
+static void freezer_change_state(struct freezer *freezer, bool freeze)
 {
-	struct freezer *freezer;
-	int retval = 0;
+	struct cgroup_subsys_state *pos;
 
-	freezer = cgroup_freezer(cgroup);
+	/*
+	 * Update all its descendants in pre-order traversal.  Each
+	 * descendant will try to inherit its parent's FREEZING state as
+	 * CGROUP_FREEZING_PARENT.
+	 */
+	mutex_lock(&freezer_mutex);
+	rcu_read_lock();
+	css_for_each_descendant_pre(pos, &freezer->css) {
+		struct freezer *pos_f = css_freezer(pos);
+		struct freezer *parent = parent_freezer(pos_f);
 
-	spin_lock_irq(&freezer->lock);
+		if (!css_tryget_online(pos))
+			continue;
+		rcu_read_unlock();
 
-	update_if_frozen(cgroup, freezer);
-	if (goal_state == freezer->state)
-		goto out;
+		if (pos_f == freezer)
+			freezer_apply_state(pos_f, freeze,
+					    CGROUP_FREEZING_SELF);
+		else
+			freezer_apply_state(pos_f,
+					    parent->state & CGROUP_FREEZING,
+					    CGROUP_FREEZING_PARENT);
 
-	switch (goal_state) {
-	case CGROUP_THAWED:
-		unfreeze_cgroup(cgroup, freezer);
-		break;
-	case CGROUP_FROZEN:
-		retval = try_to_freeze_cgroup(cgroup, freezer);
-		break;
-	default:
-		BUG();
+		rcu_read_lock();
+		css_put(pos);
 	}
-out:
-	spin_unlock_irq(&freezer->lock);
-
-	return retval;
+	rcu_read_unlock();
+	mutex_unlock(&freezer_mutex);
 }
 
-static int freezer_write(struct cgroup *cgroup,
-			 struct cftype *cft,
-			 const char *buffer)
+static ssize_t freezer_write(struct kernfs_open_file *of,
+			     char *buf, size_t nbytes, loff_t off)
 {
-	int retval;
-	enum freezer_state goal_state;
+	bool freeze;
 
-	if (strcmp(buffer, freezer_state_strs[CGROUP_THAWED]) == 0)
-		goal_state = CGROUP_THAWED;
-	else if (strcmp(buffer, freezer_state_strs[CGROUP_FROZEN]) == 0)
-		goal_state = CGROUP_FROZEN;
+	buf = strstrip(buf);
+
+	if (strcmp(buf, freezer_state_strs(0)) == 0)
+		freeze = false;
+	else if (strcmp(buf, freezer_state_strs(CGROUP_FROZEN)) == 0)
+		freeze = true;
 	else
 		return -EINVAL;
 
-	if (!cgroup_lock_live_group(cgroup))
-		return -ENODEV;
-	retval = freezer_change_state(cgroup, goal_state);
-	cgroup_unlock();
-	return retval;
+	freezer_change_state(css_freezer(of_css(of)), freeze);
+	return nbytes;
+}
+
+static u64 freezer_self_freezing_read(struct cgroup_subsys_state *css,
+				      struct cftype *cft)
+{
+	struct freezer *freezer = css_freezer(css);
+
+	return (bool)(freezer->state & CGROUP_FREEZING_SELF);
+}
+
+static u64 freezer_parent_freezing_read(struct cgroup_subsys_state *css,
+					struct cftype *cft)
+{
+	struct freezer *freezer = css_freezer(css);
+
+	return (bool)(freezer->state & CGROUP_FREEZING_PARENT);
 }
 
 static struct cftype files[] = {
 	{
 		.name = "state",
-		.read_seq_string = freezer_read,
-		.write_string = freezer_write,
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.seq_show = freezer_read,
+		.write = freezer_write,
+	},
+	{
+		.name = "self_freezing",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_u64 = freezer_self_freezing_read,
+	},
+	{
+		.name = "parent_freezing",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_u64 = freezer_parent_freezing_read,
 	},
+	{ }	/* terminate */
 };
 
-static int freezer_populate(struct cgroup_subsys *ss, struct cgroup *cgroup)
-{
-	if (!cgroup->parent)
-		return 0;
-	return cgroup_add_files(cgroup, ss, files, ARRAY_SIZE(files));
-}
-
-struct cgroup_subsys freezer_subsys = {
-	.name		= "freezer",
-	.create		= freezer_create,
-	.destroy	= freezer_destroy,
-	.populate	= freezer_populate,
-	.subsys_id	= freezer_subsys_id,
-	.can_attach	= freezer_can_attach,
-	.attach		= NULL,
+struct cgroup_subsys freezer_cgrp_subsys = {
+	.css_alloc	= freezer_css_alloc,
+	.css_online	= freezer_css_online,
+	.css_offline	= freezer_css_offline,
+	.css_free	= freezer_css_free,
+	.attach		= freezer_attach,
 	.fork		= freezer_fork,
-	.exit		= NULL,
+	.base_cftypes	= files,
 };