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 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LINUX_CGROUP_H
 #define _LINUX_CGROUP_H
 /*
  *  cgroup interface
  *
  *  Copyright (C) 2003 BULL SA
  *  Copyright (C) 2004-2006 Silicon Graphics, Inc.
  *
  */
 
 #include <linux/sched.h>
 #include <linux/cpumask.h>
 #include <linux/nodemask.h>
 #include <linux/rculist.h>
 #include <linux/cgroupstats.h>
 #include <linux/fs.h>
 #include <linux/seq_file.h>
 #include <linux/kernfs.h>
 #include <linux/jump_label.h>
 #include <linux/types.h>
 #include <linux/ns_common.h>
 #include <linux/nsproxy.h>
 #include <linux/user_namespace.h>
 #include <linux/refcount.h>
 #include <linux/kernel_stat.h>
 
 #include <linux/cgroup-defs.h>
 
 struct kernel_clone_args;
 
 #ifdef CONFIG_CGROUPS
 
 /*
  * All weight knobs on the default hierarchy should use the following min,
  * default and max values.  The default value is the logarithmic center of
  * MIN and MAX and allows 100x to be expressed in both directions.
  */
 #define CGROUP_WEIGHT_MIN       1
 #define CGROUP_WEIGHT_DFL       100
 #define CGROUP_WEIGHT_MAX       10000
 
 /* walk only threadgroup leaders */
 #define CSS_TASK_ITER_PROCS     (1U << 0)
 /* walk all threaded css_sets in the domain */
 #define CSS_TASK_ITER_THREADED      (1U << 1)
 
 /* internal flags */
 #define CSS_TASK_ITER_SKIPPED       (1U << 16)
 
 /* a css_task_iter should be treated as an opaque object */
 struct css_task_iter {
     struct cgroup_subsys        *ss;
     unsigned int            flags;
 
     struct list_head        *cset_pos;
     struct list_head        *cset_head;
 
     struct list_head        *tcset_pos;
     struct list_head        *tcset_head;
 
     struct list_head        *task_pos;
 
     struct list_head        *cur_tasks_head;
     struct css_set          *cur_cset;
     struct css_set          *cur_dcset;
     struct task_struct      *cur_task;
     struct list_head        iters_node; /* css_set->task_iters */
 };
 
 extern struct cgroup_root cgrp_dfl_root;
 extern struct css_set init_css_set;
 
 #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys;
 #include <linux/cgroup_subsys.h>
 #undef SUBSYS
 
 #define SUBSYS(_x)                              \
     extern struct static_key_true _x ## _cgrp_subsys_enabled_key;       \
     extern struct static_key_true _x ## _cgrp_subsys_on_dfl_key;
 #include <linux/cgroup_subsys.h>
 #undef SUBSYS
 
 /**
  * cgroup_subsys_enabled - fast test on whether a subsys is enabled
  * @ss: subsystem in question
  */
 #define cgroup_subsys_enabled(ss)                       \
     static_branch_likely(&ss ## _enabled_key)
 
 /**
  * cgroup_subsys_on_dfl - fast test on whether a subsys is on default hierarchy
  * @ss: subsystem in question
  */
 #define cgroup_subsys_on_dfl(ss)                        \
     static_branch_likely(&ss ## _on_dfl_key)
 
 bool css_has_online_children(struct cgroup_subsys_state *css);
 struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss);
 struct cgroup_subsys_state *cgroup_e_css(struct cgroup *cgroup,
                      struct cgroup_subsys *ss);
 struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgroup,
                          struct cgroup_subsys *ss);
 struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
                                struct cgroup_subsys *ss);
 
 struct cgroup *cgroup_get_from_path(const char *path);
 struct cgroup *cgroup_get_from_fd(int fd);
 
 int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);
 int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
 
 int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
 int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
 int cgroup_rm_cftypes(struct cftype *cfts);
 void cgroup_file_notify(struct cgroup_file *cfile);
 
 int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);
 int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry);
 int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
              struct pid *pid, struct task_struct *tsk);
 
 void cgroup_fork(struct task_struct *p);
 extern int cgroup_can_fork(struct task_struct *p,
                struct kernel_clone_args *kargs);
 extern void cgroup_cancel_fork(struct task_struct *p,
                    struct kernel_clone_args *kargs);
 extern void cgroup_post_fork(struct task_struct *p,
                  struct kernel_clone_args *kargs);
 void cgroup_exit(struct task_struct *p);
 void cgroup_release(struct task_struct *p);
 void cgroup_free(struct task_struct *p);
 
 int cgroup_init_early(void);
 int cgroup_init(void);
 
 int cgroup_parse_float(const char *input, unsigned dec_shift, s64 *v);
 
 /*
  * Iteration helpers and macros.
  */
 
 struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos,
                        struct cgroup_subsys_state *parent);
 struct cgroup_subsys_state *css_next_descendant_pre(struct cgroup_subsys_state *pos,
                             struct cgroup_subsys_state *css);
 struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state *pos);
 struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos,
                              struct cgroup_subsys_state *css);
 
 struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset,
                      struct cgroup_subsys_state **dst_cssp);
 struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset,
                     struct cgroup_subsys_state **dst_cssp);
 
 void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags,
              struct css_task_iter *it);
 struct task_struct *css_task_iter_next(struct css_task_iter *it);
 void css_task_iter_end(struct css_task_iter *it);
 
 /**
  * css_for_each_child - iterate through children of a css
  * @pos: the css * to use as the loop cursor
  * @parent: css whose children to walk
  *
  * Walk @parent's children.  Must be called under rcu_read_lock().
  *
  * If a subsystem synchronizes ->css_online() and the start of iteration, a
  * css which finished ->css_online() is guaranteed to be visible in the
  * future iterations and will stay visible until the last reference is put.
  * A css which hasn't finished ->css_online() or already finished
  * ->css_offline() may show up during traversal.  It's each subsystem's
  * responsibility to synchronize against on/offlining.
  *
  * It is allowed to temporarily drop RCU read lock during iteration.  The
  * caller is responsible for ensuring that @pos remains accessible until
  * the start of the next iteration by, for example, bumping the css refcnt.
  */
 #define css_for_each_child(pos, parent)                 \
     for ((pos) = css_next_child(NULL, (parent)); (pos);     \
          (pos) = css_next_child((pos), (parent)))
 
 /**
  * css_for_each_descendant_pre - pre-order walk of a css's descendants
  * @pos: the css * to use as the loop cursor
  * @root: css whose descendants to walk
  *
  * Walk @root's descendants.  @root is included in the iteration and the
  * first node to be visited.  Must be called under rcu_read_lock().
  *
  * If a subsystem synchronizes ->css_online() and the start of iteration, a
  * css which finished ->css_online() is guaranteed to be visible in the
  * future iterations and will stay visible until the last reference is put.
  * A css which hasn't finished ->css_online() or already finished
  * ->css_offline() may show up during traversal.  It's each subsystem's
  * responsibility to synchronize against on/offlining.
  *
  * For example, the following guarantees that a descendant can't escape
  * state updates of its ancestors.
  *
  * my_online(@css)
  * {
  *  Lock @css's parent and @css;
  *  Inherit state from the parent;
  *  Unlock both.
  * }
  *
  * my_update_state(@css)
  * {
  *  css_for_each_descendant_pre(@pos, @css) {
  *      Lock @pos;
  *      if (@pos == @css)
  *          Update @css's state;
  *      else
  *          Verify @pos is alive and inherit state from its parent;
  *      Unlock @pos;
  *  }
  * }
  *
  * As long as the inheriting step, including checking the parent state, is
  * enclosed inside @pos locking, double-locking the parent isn't necessary
  * while inheriting.  The state update to the parent is guaranteed to be
  * visible by walking order and, as long as inheriting operations to the
  * same @pos are atomic to each other, multiple updates racing each other
  * still result in the correct state.  It's guaranateed that at least one
  * inheritance happens for any css after the latest update to its parent.
  *
  * If checking parent's state requires locking the parent, each inheriting
  * iteration should lock and unlock both @pos->parent and @pos.
  *
  * Alternatively, a subsystem may choose to use a single global lock to
  * synchronize ->css_online() and ->css_offline() against tree-walking
  * operations.
  *
  * It is allowed to temporarily drop RCU read lock during iteration.  The
  * caller is responsible for ensuring that @pos remains accessible until
  * the start of the next iteration by, for example, bumping the css refcnt.
  */
 #define css_for_each_descendant_pre(pos, css)               \
     for ((pos) = css_next_descendant_pre(NULL, (css)); (pos);   \
          (pos) = css_next_descendant_pre((pos), (css)))
 
 /**
  * css_for_each_descendant_post - post-order walk of a css's descendants
  * @pos: the css * to use as the loop cursor
  * @css: css whose descendants to walk
  *
  * Similar to css_for_each_descendant_pre() but performs post-order
  * traversal instead.  @root is included in the iteration and the last
  * node to be visited.
  *
  * If a subsystem synchronizes ->css_online() and the start of iteration, a
  * css which finished ->css_online() is guaranteed to be visible in the
  * future iterations and will stay visible until the last reference is put.
  * A css which hasn't finished ->css_online() or already finished
  * ->css_offline() may show up during traversal.  It's each subsystem's
  * responsibility to synchronize against on/offlining.
  *
  * Note that the walk visibility guarantee example described in pre-order
  * walk doesn't apply the same to post-order walks.
  */
 #define css_for_each_descendant_post(pos, css)              \
     for ((pos) = css_next_descendant_post(NULL, (css)); (pos);  \
          (pos) = css_next_descendant_post((pos), (css)))
 
 /**
  * cgroup_taskset_for_each - iterate cgroup_taskset
  * @task: the loop cursor
  * @dst_css: the destination css
  * @tset: taskset to iterate
  *
  * @tset may contain multiple tasks and they may belong to multiple
  * processes.
  *
  * On the v2 hierarchy, there may be tasks from multiple processes and they
  * may not share the source or destination csses.
  *
  * On traditional hierarchies, when there are multiple tasks in @tset, if a
  * task of a process is in @tset, all tasks of the process are in @tset.
  * Also, all are guaranteed to share the same source and destination csses.
  *
  * Iteration is not in any specific order.
  */
 #define cgroup_taskset_for_each(task, dst_css, tset)            \
     for ((task) = cgroup_taskset_first((tset), &(dst_css));     \
          (task);                            \
          (task) = cgroup_taskset_next((tset), &(dst_css)))
 
 /**
  * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset
  * @leader: the loop cursor
  * @dst_css: the destination css
  * @tset: taskset to iterate
  *
  * Iterate threadgroup leaders of @tset.  For single-task migrations, @tset
  * may not contain any.
  */
 #define cgroup_taskset_for_each_leader(leader, dst_css, tset)       \
     for ((leader) = cgroup_taskset_first((tset), &(dst_css));   \
          (leader);                          \
          (leader) = cgroup_taskset_next((tset), &(dst_css)))    \
         if ((leader) != (leader)->group_leader)         \
             ;                       \
         else
 
 /*
  * Inline functions.
  */
 
 static inline u64 cgroup_id(const struct cgroup *cgrp)
 {
     return cgrp->kn->id;
 }
 
 /**
  * css_get - obtain a reference on the specified css
  * @css: target css
  *
  * The caller must already have a reference.
  */
 static inline void css_get(struct cgroup_subsys_state *css)
 {
     if (!(css->flags & CSS_NO_REF))
         percpu_ref_get(&css->refcnt);
 }
 
 /**
  * css_get_many - obtain references on the specified css
  * @css: target css
  * @n: number of references to get
  *
  * The caller must already have a reference.
  */
 static inline void css_get_many(struct cgroup_subsys_state *css, unsigned int n)
 {
     if (!(css->flags & CSS_NO_REF))
         percpu_ref_get_many(&css->refcnt, n);
 }
 
 /**
  * css_tryget - try to obtain a reference on the specified css
  * @css: target css
  *
  * Obtain a reference on @css unless it already has reached zero and is
  * being released.  This function doesn't care whether @css is on or
  * offline.  The caller naturally needs to ensure that @css is accessible
  * but doesn't have to be holding a reference on it - IOW, RCU protected
  * access is good enough for this function.  Returns %true if a reference
  * count was successfully obtained; %false otherwise.
  */
 static inline bool css_tryget(struct cgroup_subsys_state *css)
 {
     if (!(css->flags & CSS_NO_REF))
         return percpu_ref_tryget(&css->refcnt);
     return true;
 }
 
 /**
  * css_tryget_online - try to obtain a reference on the specified css if online
  * @css: target css
  *
  * Obtain a reference on @css if it's online.  The caller naturally needs
  * to ensure that @css is accessible but doesn't have to be holding a
  * reference on it - IOW, RCU protected access is good enough for this
  * function.  Returns %true if a reference count was successfully obtained;
  * %false otherwise.
  */
 static inline bool css_tryget_online(struct cgroup_subsys_state *css)
 {
     if (!(css->flags & CSS_NO_REF))
         return percpu_ref_tryget_live(&css->refcnt);
     return true;
 }
 
 /**
  * css_is_dying - test whether the specified css is dying
  * @css: target css
  *
  * Test whether @css is in the process of offlining or already offline.  In
  * most cases, ->css_online() and ->css_offline() callbacks should be
  * enough; however, the actual offline operations are RCU delayed and this
  * test returns %true also when @css is scheduled to be offlined.
  *
  * This is useful, for example, when the use case requires synchronous
  * behavior with respect to cgroup removal.  cgroup removal schedules css
  * offlining but the css can seem alive while the operation is being
  * delayed.  If the delay affects user visible semantics, this test can be
  * used to resolve the situation.
  */
 static inline bool css_is_dying(struct cgroup_subsys_state *css)
 {
     return !(css->flags & CSS_NO_REF) && percpu_ref_is_dying(&css->refcnt);
 }
 
 /**
  * css_put - put a css reference
  * @css: target css
  *
  * Put a reference obtained via css_get() and css_tryget_online().
  */
 static inline void css_put(struct cgroup_subsys_state *css)
 {
     if (!(css->flags & CSS_NO_REF))
         percpu_ref_put(&css->refcnt);
 }
 
 /**
  * css_put_many - put css references
  * @css: target css
  * @n: number of references to put
  *
  * Put references obtained via css_get() and css_tryget_online().
  */
 static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n)
 {
     if (!(css->flags & CSS_NO_REF))
         percpu_ref_put_many(&css->refcnt, n);
 }
 
 static inline void cgroup_get(struct cgroup *cgrp)
 {
     css_get(&cgrp->self);
 }
 
 static inline bool cgroup_tryget(struct cgroup *cgrp)
 {
     return css_tryget(&cgrp->self);
 }
 
 static inline void cgroup_put(struct cgroup *cgrp)
 {
     css_put(&cgrp->self);
 }
 
 /**
  * task_css_set_check - obtain a task's css_set with extra access conditions
  * @task: the task to obtain css_set for
  * @__c: extra condition expression to be passed to rcu_dereference_check()
  *
  * A task's css_set is RCU protected, initialized and exited while holding
  * task_lock(), and can only be modified while holding both cgroup_mutex
  * and task_lock() while the task is alive.  This macro verifies that the
  * caller is inside proper critical section and returns @task's css_set.
  *
  * The caller can also specify additional allowed conditions via @__c, such
  * as locks used during the cgroup_subsys::attach() methods.
  */
 #ifdef CONFIG_PROVE_RCU
 extern struct mutex cgroup_mutex;
 extern spinlock_t css_set_lock;
 #define task_css_set_check(task, __c)                   \
     rcu_dereference_check((task)->cgroups,              \
         rcu_read_lock_sched_held() ||               \
         lockdep_is_held(&cgroup_mutex) ||           \
         lockdep_is_held(&css_set_lock) ||           \
         ((task)->flags & PF_EXITING) || (__c))
 #else
 #define task_css_set_check(task, __c)                   \
     rcu_dereference((task)->cgroups)
 #endif
 
 /**
  * task_css_check - obtain css for (task, subsys) w/ extra access conds
  * @task: the target task
  * @subsys_id: the target subsystem ID
  * @__c: extra condition expression to be passed to rcu_dereference_check()
  *
  * Return the cgroup_subsys_state for the (@task, @subsys_id) pair.  The
  * synchronization rules are the same as task_css_set_check().
  */
 #define task_css_check(task, subsys_id, __c)                \
     task_css_set_check((task), (__c))->subsys[(subsys_id)]
 
 /**
  * task_css_set - obtain a task's css_set
  * @task: the task to obtain css_set for
  *
  * See task_css_set_check().
  */
 static inline struct css_set *task_css_set(struct task_struct *task)
 {
     return task_css_set_check(task, false);
 }
 
 /**
  * task_css - obtain css for (task, subsys)
  * @task: the target task
  * @subsys_id: the target subsystem ID
  *
  * See task_css_check().
  */
 static inline struct cgroup_subsys_state *task_css(struct task_struct *task,
                            int subsys_id)
 {
     return task_css_check(task, subsys_id, false);
 }
 
 /**
  * task_get_css - find and get the css for (task, subsys)
  * @task: the target task
  * @subsys_id: the target subsystem ID
  *
  * Find the css for the (@task, @subsys_id) combination, increment a
  * reference on and return it.  This function is guaranteed to return a
  * valid css.  The returned css may already have been offlined.
  */
 static inline struct cgroup_subsys_state *
 task_get_css(struct task_struct *task, int subsys_id)
 {
     struct cgroup_subsys_state *css;
 
     rcu_read_lock();
     while (true) {
         css = task_css(task, subsys_id);
         /*
          * Can't use css_tryget_online() here.  A task which has
          * PF_EXITING set may stay associated with an offline css.
          * If such task calls this function, css_tryget_online()
          * will keep failing.
          */
         if (likely(css_tryget(css)))
             break;
         cpu_relax();
     }
     rcu_read_unlock();
     return css;
 }
 
 /**
  * task_css_is_root - test whether a task belongs to the root css
  * @task: the target task
  * @subsys_id: the target subsystem ID
  *
  * Test whether @task belongs to the root css on the specified subsystem.
  * May be invoked in any context.
  */
 static inline bool task_css_is_root(struct task_struct *task, int subsys_id)
 {
     return task_css_check(task, subsys_id, true) ==
         init_css_set.subsys[subsys_id];
 }
 
 static inline struct cgroup *task_cgroup(struct task_struct *task,
                      int subsys_id)
 {
     return task_css(task, subsys_id)->cgroup;
 }
 
 static inline struct cgroup *task_dfl_cgroup(struct task_struct *task)
 {
     return task_css_set(task)->dfl_cgrp;
 }
 
 static inline struct cgroup *cgroup_parent(struct cgroup *cgrp)
 {
     struct cgroup_subsys_state *parent_css = cgrp->self.parent;
 
     if (parent_css)
         return container_of(parent_css, struct cgroup, self);
     return NULL;
 }
 
 /**
  * cgroup_is_descendant - test ancestry
  * @cgrp: the cgroup to be tested
  * @ancestor: possible ancestor of @cgrp
  *
  * Test whether @cgrp is a descendant of @ancestor.  It also returns %true
  * if @cgrp == @ancestor.  This function is safe to call as long as @cgrp
  * and @ancestor are accessible.
  */
 static inline bool cgroup_is_descendant(struct cgroup *cgrp,
                     struct cgroup *ancestor)
 {
     if (cgrp->root != ancestor->root || cgrp->level < ancestor->level)
         return false;
     return cgrp->ancestor_ids[ancestor->level] == cgroup_id(ancestor);
 }
 
 /**
  * cgroup_ancestor - find ancestor of cgroup
  * @cgrp: cgroup to find ancestor of
  * @ancestor_level: level of ancestor to find starting from root
  *
  * Find ancestor of cgroup at specified level starting from root if it exists
  * and return pointer to it. Return NULL if @cgrp doesn't have ancestor at
  * @ancestor_level.
  *
  * This function is safe to call as long as @cgrp is accessible.
  */
 static inline struct cgroup *cgroup_ancestor(struct cgroup *cgrp,
                          int ancestor_level)
 {
     if (cgrp->level < ancestor_level)
         return NULL;
     while (cgrp && cgrp->level > ancestor_level)
         cgrp = cgroup_parent(cgrp);
     return cgrp;
 }
 
 /**
  * task_under_cgroup_hierarchy - test task's membership of cgroup ancestry
  * @task: the task to be tested
  * @ancestor: possible ancestor of @task's cgroup
  *
  * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor.
  * It follows all the same rules as cgroup_is_descendant, and only applies
  * to the default hierarchy.
  */
 static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
                            struct cgroup *ancestor)
 {
     struct css_set *cset = task_css_set(task);
 
     return cgroup_is_descendant(cset->dfl_cgrp, ancestor);
 }
 
 /* no synchronization, the result can only be used as a hint */
 static inline bool cgroup_is_populated(struct cgroup *cgrp)
 {
     return cgrp->nr_populated_csets + cgrp->nr_populated_domain_children +
         cgrp->nr_populated_threaded_children;
 }
 
 /* returns ino associated with a cgroup */
 static inline ino_t cgroup_ino(struct cgroup *cgrp)
 {
     return kernfs_ino(cgrp->kn);
 }
 
 /* cft/css accessors for cftype->write() operation */
 static inline struct cftype *of_cft(struct kernfs_open_file *of)
 {
     return of->kn->priv;
 }
 
 struct cgroup_subsys_state *of_css(struct kernfs_open_file *of);
 
 /* cft/css accessors for cftype->seq_*() operations */
 static inline struct cftype *seq_cft(struct seq_file *seq)
 {
     return of_cft(seq->private);
 }
 
 static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq)
 {
     return of_css(seq->private);
 }
 
 /*
  * Name / path handling functions.  All are thin wrappers around the kernfs
  * counterparts and can be called under any context.
  */
 
 static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen)
 {
     return kernfs_name(cgrp->kn, buf, buflen);
 }
 
 static inline int cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen)
 {
     return kernfs_path(cgrp->kn, buf, buflen);
 }
 
 static inline void pr_cont_cgroup_name(struct cgroup *cgrp)
 {
     pr_cont_kernfs_name(cgrp->kn);
 }
 
 static inline void pr_cont_cgroup_path(struct cgroup *cgrp)
 {
     pr_cont_kernfs_path(cgrp->kn);
 }
 
 static inline struct psi_group *cgroup_psi(struct cgroup *cgrp)
 {
     return cgrp->psi;
 }
 
 bool cgroup_psi_enabled(void);
 
 static inline void cgroup_init_kthreadd(void)
 {
     /*
      * kthreadd is inherited by all kthreads, keep it in the root so
      * that the new kthreads are guaranteed to stay in the root until
      * initialization is finished.
      */
     current->no_cgroup_migration = 1;
 }
 
 static inline void cgroup_kthread_ready(void)
 {
     /*
      * This kthread finished initialization.  The creator should have
      * set PF_NO_SETAFFINITY if this kthread should stay in the root.
      */
     current->no_cgroup_migration = 0;
 }
 
 void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen);
 struct cgroup *cgroup_get_from_id(u64 id);
 #else /* !CONFIG_CGROUPS */
 
 struct cgroup_subsys_state;
 struct cgroup;
 
 static inline u64 cgroup_id(const struct cgroup *cgrp) { return 1; }
 static inline void css_get(struct cgroup_subsys_state *css) {}
 static inline void css_put(struct cgroup_subsys_state *css) {}
 static inline int cgroup_attach_task_all(struct task_struct *from,
                      struct task_struct *t) { return 0; }
 static inline int cgroupstats_build(struct cgroupstats *stats,
                     struct dentry *dentry) { return -EINVAL; }
 
 static inline void cgroup_fork(struct task_struct *p) {}
 static inline int cgroup_can_fork(struct task_struct *p,
                   struct kernel_clone_args *kargs) { return 0; }
 static inline void cgroup_cancel_fork(struct task_struct *p,
                       struct kernel_clone_args *kargs) {}
 static inline void cgroup_post_fork(struct task_struct *p,
                     struct kernel_clone_args *kargs) {}
 static inline void cgroup_exit(struct task_struct *p) {}
 static inline void cgroup_release(struct task_struct *p) {}
 static inline void cgroup_free(struct task_struct *p) {}
 
 static inline int cgroup_init_early(void) { return 0; }
 static inline int cgroup_init(void) { return 0; }
 static inline void cgroup_init_kthreadd(void) {}
 static inline void cgroup_kthread_ready(void) {}
 
 static inline struct cgroup *cgroup_parent(struct cgroup *cgrp)
 {
     return NULL;
 }
 
 static inline bool cgroup_psi_enabled(void)
 {
     return false;
 }
 
 static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
                            struct cgroup *ancestor)
 {
     return true;
 }
 
 static inline void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen)
 {}
 
 static inline struct cgroup *cgroup_get_from_id(u64 id)
 {
     return NULL;
 }
 #endif /* !CONFIG_CGROUPS */
 
 #ifdef CONFIG_CGROUPS
 /*
  * cgroup scalable recursive statistics.
  */
 void cgroup_rstat_updated(struct cgroup *cgrp, int cpu);
 void cgroup_rstat_flush(struct cgroup *cgrp);
 void cgroup_rstat_flush_irqsafe(struct cgroup *cgrp);
 void cgroup_rstat_flush_hold(struct cgroup *cgrp);
 void cgroup_rstat_flush_release(void);
 
 /*
  * Basic resource stats.
  */
 #ifdef CONFIG_CGROUP_CPUACCT
 void cpuacct_charge(struct task_struct *tsk, u64 cputime);
 void cpuacct_account_field(struct task_struct *tsk, int index, u64 val);
 #else
 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
 static inline void cpuacct_account_field(struct task_struct *tsk, int index,
                      u64 val) {}
 #endif
 
 void __cgroup_account_cputime(struct cgroup *cgrp, u64 delta_exec);
 void __cgroup_account_cputime_field(struct cgroup *cgrp,
                     enum cpu_usage_stat index, u64 delta_exec);
 
 static inline void cgroup_account_cputime(struct task_struct *task,
                       u64 delta_exec)
 {
     struct cgroup *cgrp;
 
     cpuacct_charge(task, delta_exec);
 
     cgrp = task_dfl_cgroup(task);
     if (cgroup_parent(cgrp))
         __cgroup_account_cputime(cgrp, delta_exec);
 }
 
 static inline void cgroup_account_cputime_field(struct task_struct *task,
                         enum cpu_usage_stat index,
                         u64 delta_exec)
 {
     struct cgroup *cgrp;
 
     cpuacct_account_field(task, index, delta_exec);
 
     cgrp = task_dfl_cgroup(task);
     if (cgroup_parent(cgrp))
         __cgroup_account_cputime_field(cgrp, index, delta_exec);
 }
 
 #else   /* CONFIG_CGROUPS */
 
 static inline void cgroup_account_cputime(struct task_struct *task,
                       u64 delta_exec) {}
 static inline void cgroup_account_cputime_field(struct task_struct *task,
                         enum cpu_usage_stat index,
                         u64 delta_exec) {}
 
 #endif  /* CONFIG_CGROUPS */
 
 /*
  * sock->sk_cgrp_data handling.  For more info, see sock_cgroup_data
  * definition in cgroup-defs.h.
  */
 #ifdef CONFIG_SOCK_CGROUP_DATA
 
 void cgroup_sk_alloc(struct sock_cgroup_data *skcd);
 void cgroup_sk_clone(struct sock_cgroup_data *skcd);
 void cgroup_sk_free(struct sock_cgroup_data *skcd);
 
 static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd)
 {
     return skcd->cgroup;
 }
 
 #else   /* CONFIG_CGROUP_DATA */
 
 static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {}
 static inline void cgroup_sk_clone(struct sock_cgroup_data *skcd) {}
 static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {}
 
 #endif  /* CONFIG_CGROUP_DATA */
 
 struct cgroup_namespace {
     struct ns_common    ns;
     struct user_namespace   *user_ns;
     struct ucounts      *ucounts;
     struct css_set          *root_cset;
 };
 
 extern struct cgroup_namespace init_cgroup_ns;
 
 #ifdef CONFIG_CGROUPS
 
 void free_cgroup_ns(struct cgroup_namespace *ns);
 
 struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,
                     struct user_namespace *user_ns,
                     struct cgroup_namespace *old_ns);
 
 int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
            struct cgroup_namespace *ns);
 
 #else /* !CONFIG_CGROUPS */
 
 static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
 static inline struct cgroup_namespace *
 copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
            struct cgroup_namespace *old_ns)
 {
     return old_ns;
 }
 
 #endif /* !CONFIG_CGROUPS */
 
 static inline void get_cgroup_ns(struct cgroup_namespace *ns)
 {
     if (ns)
         refcount_inc(&ns->ns.count);
 }
 
 static inline void put_cgroup_ns(struct cgroup_namespace *ns)
 {
     if (ns && refcount_dec_and_test(&ns->ns.count))
         free_cgroup_ns(ns);
 }
 
 #ifdef CONFIG_CGROUPS
 
 void cgroup_enter_frozen(void);
 void cgroup_leave_frozen(bool always_leave);
 void cgroup_update_frozen(struct cgroup *cgrp);
 void cgroup_freeze(struct cgroup *cgrp, bool freeze);
 void cgroup_freezer_migrate_task(struct task_struct *task, struct cgroup *src,
                  struct cgroup *dst);
 
 static inline bool cgroup_task_frozen(struct task_struct *task)
 {
     return task->frozen;
 }
 
 #else /* !CONFIG_CGROUPS */
 
 static inline void cgroup_enter_frozen(void) { }
 static inline void cgroup_leave_frozen(bool always_leave) { }
 static inline bool cgroup_task_frozen(struct task_struct *task)
 {
     return false;
 }
 
 #endif /* !CONFIG_CGROUPS */
 
 #ifdef CONFIG_CGROUP_BPF
 static inline void cgroup_bpf_get(struct cgroup *cgrp)
 {
     percpu_ref_get(&cgrp->bpf.refcnt);
 }
 
 static inline void cgroup_bpf_put(struct cgroup *cgrp)
 {
     percpu_ref_put(&cgrp->bpf.refcnt);
 }
 
 #else /* CONFIG_CGROUP_BPF */
 
 static inline void cgroup_bpf_get(struct cgroup *cgrp) {}
 static inline void cgroup_bpf_put(struct cgroup *cgrp) {}
 
 #endif /* CONFIG_CGROUP_BPF */
 
 #endif /* _LINUX_CGROUP_H */

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