1 files changed, 59 insertions, 17 deletions

diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 8492721b39be..60d44b26276d 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -76,6 +76,7 @@ enum {
         CFTYPE_ONLY_ON_ROOT     = (1 << 0),     /* only create on root cgrp */
         CFTYPE_NOT_ON_ROOT      = (1 << 1),     /* don't create on root cgrp */
         CFTYPE_NO_PREFIX        = (1 << 3),     /* (DON'T USE FOR NEW FILES) no subsys prefix */
+        CFTYPE_WORLD_WRITABLE   = (1 << 4),     /* (DON'T USE FOR NEW FILES) S_IWUGO */
 
         /* internal flags, do not use outside cgroup core proper */
         __CFTYPE_ONLY_ON_DFL    = (1 << 16),    /* only on default hierarchy */
@@ -83,6 +84,17 @@ enum {
 };
 
 /*
+ * cgroup_file is the handle for a file instance created in a cgroup which
+ * is used, for example, to generate file changed notifications.  This can
+ * be obtained by setting cftype->file_offset.
+ */
+struct cgroup_file {
+        /* do not access any fields from outside cgroup core */
+        struct list_head node;                  /* anchored at css->files */
+        struct kernfs_node *kn;
+};
+
+/*
  * Per-subsystem/per-cgroup state maintained by the system.  This is the
  * fundamental structural building block that controllers deal with.
  *
@@ -122,6 +134,9 @@ struct cgroup_subsys_state {
          */
         u64 serial_nr;
 
+        /* all cgroup_files associated with this css */
+        struct list_head files;
+
         /* percpu_ref killing and RCU release */
         struct rcu_head rcu_head;
         struct work_struct destroy_work;
@@ -196,6 +211,9 @@ struct css_set {
          */
         struct list_head e_cset_node[CGROUP_SUBSYS_COUNT];
 
+        /* all css_task_iters currently walking this cset */
+        struct list_head task_iters;
+
         /* For RCU-protected deletion */
         struct rcu_head rcu_head;
 };
@@ -217,16 +235,16 @@ struct cgroup {
         int id;
 
         /*
-         * If this cgroup contains any tasks, it contributes one to
-         * populated_cnt.  All children with non-zero popuplated_cnt of
-         * their own contribute one.  The count is zero iff there's no task
-         * in this cgroup or its subtree.
+         * Each non-empty css_set associated with this cgroup contributes
+         * one to populated_cnt.  All children with non-zero popuplated_cnt
+         * of their own contribute one.  The count is zero iff there's no
+         * task in this cgroup or its subtree.
          */
         int populated_cnt;
 
         struct kernfs_node *kn;         /* cgroup kernfs entry */
-        struct kernfs_node *procs_kn;   /* kn for "cgroup.procs" */
-        struct kernfs_node *populated_kn; /* kn for "cgroup.subtree_populated" */
+        struct cgroup_file procs_file;  /* handle for "cgroup.procs" */
+        struct cgroup_file events_file; /* handle for "cgroup.events" */
 
         /*
          * The bitmask of subsystems enabled on the child cgroups.
@@ -324,11 +342,6 @@ struct cftype {
          */
         char name[MAX_CFTYPE_NAME];
         unsigned long private;
-        /*
-         * If not 0, file mode is set to this value, otherwise it will
-         * be figured out automatically
-         */
-        umode_t mode;
 
         /*
          * The maximum length of string, excluding trailing nul, that can
@@ -340,6 +353,14 @@ struct cftype {
         unsigned int flags;
 
         /*
+         * If non-zero, should contain the offset from the start of css to
+         * a struct cgroup_file field.  cgroup will record the handle of
+         * the created file into it.  The recorded handle can be used as
+         * long as the containing css remains accessible.
+         */
+        unsigned int file_offset;
+
+        /*
          * Fields used for internal bookkeeping.  Initialized automatically
          * during registration.
          */
@@ -414,12 +435,10 @@ struct cgroup_subsys {
         int (*can_fork)(struct task_struct *task, void **priv_p);
         void (*cancel_fork)(struct task_struct *task, void *priv);
         void (*fork)(struct task_struct *task, void *priv);
-        void (*exit)(struct cgroup_subsys_state *css,
-                     struct cgroup_subsys_state *old_css,
-                     struct task_struct *task);
+        void (*exit)(struct task_struct *task);
+        void (*free)(struct task_struct *task);
         void (*bind)(struct cgroup_subsys_state *root_css);
 
-        int disabled;
         int early_init;
 
         /*
@@ -473,8 +492,31 @@ struct cgroup_subsys {
         unsigned int depends_on;
 };
 
-void cgroup_threadgroup_change_begin(struct task_struct *tsk);
-void cgroup_threadgroup_change_end(struct task_struct *tsk);
+extern struct percpu_rw_semaphore cgroup_threadgroup_rwsem;
+
+/**
+ * cgroup_threadgroup_change_begin - threadgroup exclusion for cgroups
+ * @tsk: target task
+ *
+ * Called from threadgroup_change_begin() and allows cgroup operations to
+ * synchronize against threadgroup changes using a percpu_rw_semaphore.
+ */
+static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk)
+{
+        percpu_down_read(&cgroup_threadgroup_rwsem);
+}
+
+/**
+ * cgroup_threadgroup_change_end - threadgroup exclusion for cgroups
+ * @tsk: target task
+ *
+ * Called from threadgroup_change_end().  Counterpart of
+ * cgroup_threadcgroup_change_begin().
+ */
+static inline void cgroup_threadgroup_change_end(struct task_struct *tsk)
+{
+        percpu_up_read(&cgroup_threadgroup_rwsem);
+}
 
 #else   /* CONFIG_CGROUPS */