1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_CGROUP_H
3#define _LINUX_CGROUP_H
4/*
5 * cgroup interface
6 *
7 * Copyright (C) 2003 BULL SA
8 * Copyright (C) 2004-2006 Silicon Graphics, Inc.
9 *
10 */
11
12#include <linux/sched.h>
13#include <linux/cpumask.h>
14#include <linux/nodemask.h>
15#include <linux/rculist.h>
16#include <linux/cgroupstats.h>
17#include <linux/fs.h>
18#include <linux/seq_file.h>
19#include <linux/kernfs.h>
20#include <linux/jump_label.h>
21#include <linux/types.h>
22#include <linux/ns_common.h>
23#include <linux/nsproxy.h>
24#include <linux/user_namespace.h>
25#include <linux/refcount.h>
26#include <linux/kernel_stat.h>
27
28#include <linux/cgroup-defs.h>
29
30#ifdef CONFIG_CGROUPS
31
32/*
33 * All weight knobs on the default hierarhcy should use the following min,
34 * default and max values. The default value is the logarithmic center of
35 * MIN and MAX and allows 100x to be expressed in both directions.
36 */
37#define CGROUP_WEIGHT_MIN 1
38#define CGROUP_WEIGHT_DFL 100
39#define CGROUP_WEIGHT_MAX 10000
40
41/* walk only threadgroup leaders */
42#define CSS_TASK_ITER_PROCS (1U << 0)
43/* walk all threaded css_sets in the domain */
44#define CSS_TASK_ITER_THREADED (1U << 1)
45
46/* a css_task_iter should be treated as an opaque object */
47struct css_task_iter {
48 struct cgroup_subsys *ss;
49 unsigned int flags;
50
51 struct list_head *cset_pos;
52 struct list_head *cset_head;
53
54 struct list_head *tcset_pos;
55 struct list_head *tcset_head;
56
57 struct list_head *task_pos;
58 struct list_head *tasks_head;
59 struct list_head *mg_tasks_head;
60
61 struct css_set *cur_cset;
62 struct css_set *cur_dcset;
63 struct task_struct *cur_task;
64 struct list_head iters_node; /* css_set->task_iters */
65};
66
67extern struct cgroup_root cgrp_dfl_root;
68extern struct css_set init_css_set;
69
70#define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys;
71#include <linux/cgroup_subsys.h>
72#undef SUBSYS
73
74#define SUBSYS(_x) \
75 extern struct static_key_true _x ## _cgrp_subsys_enabled_key; \
76 extern struct static_key_true _x ## _cgrp_subsys_on_dfl_key;
77#include <linux/cgroup_subsys.h>
78#undef SUBSYS
79
80/**
81 * cgroup_subsys_enabled - fast test on whether a subsys is enabled
82 * @ss: subsystem in question
83 */
84#define cgroup_subsys_enabled(ss) \
85 static_branch_likely(&ss ## _enabled_key)
86
87/**
88 * cgroup_subsys_on_dfl - fast test on whether a subsys is on default hierarchy
89 * @ss: subsystem in question
90 */
91#define cgroup_subsys_on_dfl(ss) \
92 static_branch_likely(&ss ## _on_dfl_key)
93
94bool css_has_online_children(struct cgroup_subsys_state *css);
95struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss);
96struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgroup,
97 struct cgroup_subsys *ss);
98struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
99 struct cgroup_subsys *ss);
100
101struct cgroup *cgroup_get_from_path(const char *path);
102struct cgroup *cgroup_get_from_fd(int fd);
103
104int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);
105int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
106
107int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
108int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
109int cgroup_rm_cftypes(struct cftype *cfts);
110void cgroup_file_notify(struct cgroup_file *cfile);
111
112int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);
113int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry);
114int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
115 struct pid *pid, struct task_struct *tsk);
116
117void cgroup_fork(struct task_struct *p);
118extern int cgroup_can_fork(struct task_struct *p);
119extern void cgroup_cancel_fork(struct task_struct *p);
120extern void cgroup_post_fork(struct task_struct *p);
121void cgroup_exit(struct task_struct *p);
122void cgroup_free(struct task_struct *p);
123
124int cgroup_init_early(void);
125int cgroup_init(void);
126
127/*
128 * Iteration helpers and macros.
129 */
130
131struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos,
132 struct cgroup_subsys_state *parent);
133struct cgroup_subsys_state *css_next_descendant_pre(struct cgroup_subsys_state *pos,
134 struct cgroup_subsys_state *css);
135struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state *pos);
136struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos,
137 struct cgroup_subsys_state *css);
138
139struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset,
140 struct cgroup_subsys_state **dst_cssp);
141struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset,
142 struct cgroup_subsys_state **dst_cssp);
143
144void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags,
145 struct css_task_iter *it);
146struct task_struct *css_task_iter_next(struct css_task_iter *it);
147void css_task_iter_end(struct css_task_iter *it);
148
149/**
150 * css_for_each_child - iterate through children of a css
151 * @pos: the css * to use as the loop cursor
152 * @parent: css whose children to walk
153 *
154 * Walk @parent's children. Must be called under rcu_read_lock().
155 *
156 * If a subsystem synchronizes ->css_online() and the start of iteration, a
157 * css which finished ->css_online() is guaranteed to be visible in the
158 * future iterations and will stay visible until the last reference is put.
159 * A css which hasn't finished ->css_online() or already finished
160 * ->css_offline() may show up during traversal. It's each subsystem's
161 * responsibility to synchronize against on/offlining.
162 *
163 * It is allowed to temporarily drop RCU read lock during iteration. The
164 * caller is responsible for ensuring that @pos remains accessible until
165 * the start of the next iteration by, for example, bumping the css refcnt.
166 */
167#define css_for_each_child(pos, parent) \
168 for ((pos) = css_next_child(NULL, (parent)); (pos); \
169 (pos) = css_next_child((pos), (parent)))
170
171/**
172 * css_for_each_descendant_pre - pre-order walk of a css's descendants
173 * @pos: the css * to use as the loop cursor
174 * @root: css whose descendants to walk
175 *
176 * Walk @root's descendants. @root is included in the iteration and the
177 * first node to be visited. Must be called under rcu_read_lock().
178 *
179 * If a subsystem synchronizes ->css_online() and the start of iteration, a
180 * css which finished ->css_online() is guaranteed to be visible in the
181 * future iterations and will stay visible until the last reference is put.
182 * A css which hasn't finished ->css_online() or already finished
183 * ->css_offline() may show up during traversal. It's each subsystem's
184 * responsibility to synchronize against on/offlining.
185 *
186 * For example, the following guarantees that a descendant can't escape
187 * state updates of its ancestors.
188 *
189 * my_online(@css)
190 * {
191 * Lock @css's parent and @css;
192 * Inherit state from the parent;
193 * Unlock both.
194 * }
195 *
196 * my_update_state(@css)
197 * {
198 * css_for_each_descendant_pre(@pos, @css) {
199 * Lock @pos;
200 * if (@pos == @css)
201 * Update @css's state;
202 * else
203 * Verify @pos is alive and inherit state from its parent;
204 * Unlock @pos;
205 * }
206 * }
207 *
208 * As long as the inheriting step, including checking the parent state, is
209 * enclosed inside @pos locking, double-locking the parent isn't necessary
210 * while inheriting. The state update to the parent is guaranteed to be
211 * visible by walking order and, as long as inheriting operations to the
212 * same @pos are atomic to each other, multiple updates racing each other
213 * still result in the correct state. It's guaranateed that at least one
214 * inheritance happens for any css after the latest update to its parent.
215 *
216 * If checking parent's state requires locking the parent, each inheriting
217 * iteration should lock and unlock both @pos->parent and @pos.
218 *
219 * Alternatively, a subsystem may choose to use a single global lock to
220 * synchronize ->css_online() and ->css_offline() against tree-walking
221 * operations.
222 *
223 * It is allowed to temporarily drop RCU read lock during iteration. The
224 * caller is responsible for ensuring that @pos remains accessible until
225 * the start of the next iteration by, for example, bumping the css refcnt.
226 */
227#define css_for_each_descendant_pre(pos, css) \
228 for ((pos) = css_next_descendant_pre(NULL, (css)); (pos); \
229 (pos) = css_next_descendant_pre((pos), (css)))
230
231/**
232 * css_for_each_descendant_post - post-order walk of a css's descendants
233 * @pos: the css * to use as the loop cursor
234 * @css: css whose descendants to walk
235 *
236 * Similar to css_for_each_descendant_pre() but performs post-order
237 * traversal instead. @root is included in the iteration and the last
238 * node to be visited.
239 *
240 * If a subsystem synchronizes ->css_online() and the start of iteration, a
241 * css which finished ->css_online() is guaranteed to be visible in the
242 * future iterations and will stay visible until the last reference is put.
243 * A css which hasn't finished ->css_online() or already finished
244 * ->css_offline() may show up during traversal. It's each subsystem's
245 * responsibility to synchronize against on/offlining.
246 *
247 * Note that the walk visibility guarantee example described in pre-order
248 * walk doesn't apply the same to post-order walks.
249 */
250#define css_for_each_descendant_post(pos, css) \
251 for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \
252 (pos) = css_next_descendant_post((pos), (css)))
253
254/**
255 * cgroup_taskset_for_each - iterate cgroup_taskset
256 * @task: the loop cursor
257 * @dst_css: the destination css
258 * @tset: taskset to iterate
259 *
260 * @tset may contain multiple tasks and they may belong to multiple
261 * processes.
262 *
263 * On the v2 hierarchy, there may be tasks from multiple processes and they
264 * may not share the source or destination csses.
265 *
266 * On traditional hierarchies, when there are multiple tasks in @tset, if a
267 * task of a process is in @tset, all tasks of the process are in @tset.
268 * Also, all are guaranteed to share the same source and destination csses.
269 *
270 * Iteration is not in any specific order.
271 */
272#define cgroup_taskset_for_each(task, dst_css, tset) \
273 for ((task) = cgroup_taskset_first((tset), &(dst_css)); \
274 (task); \
275 (task) = cgroup_taskset_next((tset), &(dst_css)))
276
277/**
278 * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset
279 * @leader: the loop cursor
280 * @dst_css: the destination css
281 * @tset: taskset to iterate
282 *
283 * Iterate threadgroup leaders of @tset. For single-task migrations, @tset
284 * may not contain any.
285 */
286#define cgroup_taskset_for_each_leader(leader, dst_css, tset) \
287 for ((leader) = cgroup_taskset_first((tset), &(dst_css)); \
288 (leader); \
289 (leader) = cgroup_taskset_next((tset), &(dst_css))) \
290 if ((leader) != (leader)->group_leader) \
291 ; \
292 else
293
294/*
295 * Inline functions.
296 */
297
298/**
299 * css_get - obtain a reference on the specified css
300 * @css: target css
301 *
302 * The caller must already have a reference.
303 */
304static inline void css_get(struct cgroup_subsys_state *css)
305{
306 if (!(css->flags & CSS_NO_REF))
307 percpu_ref_get(&css->refcnt);
308}
309
310/**
311 * css_get_many - obtain references on the specified css
312 * @css: target css
313 * @n: number of references to get
314 *
315 * The caller must already have a reference.
316 */
317static inline void css_get_many(struct cgroup_subsys_state *css, unsigned int n)
318{
319 if (!(css->flags & CSS_NO_REF))
320 percpu_ref_get_many(&css->refcnt, n);
321}
322
323/**
324 * css_tryget - try to obtain a reference on the specified css
325 * @css: target css
326 *
327 * Obtain a reference on @css unless it already has reached zero and is
328 * being released. This function doesn't care whether @css is on or
329 * offline. The caller naturally needs to ensure that @css is accessible
330 * but doesn't have to be holding a reference on it - IOW, RCU protected
331 * access is good enough for this function. Returns %true if a reference
332 * count was successfully obtained; %false otherwise.
333 */
334static inline bool css_tryget(struct cgroup_subsys_state *css)
335{
336 if (!(css->flags & CSS_NO_REF))
337 return percpu_ref_tryget(&css->refcnt);
338 return true;
339}
340
341/**
342 * css_tryget_online - try to obtain a reference on the specified css if online
343 * @css: target css
344 *
345 * Obtain a reference on @css if it's online. The caller naturally needs
346 * to ensure that @css is accessible but doesn't have to be holding a
347 * reference on it - IOW, RCU protected access is good enough for this
348 * function. Returns %true if a reference count was successfully obtained;
349 * %false otherwise.
350 */
351static inline bool css_tryget_online(struct cgroup_subsys_state *css)
352{
353 if (!(css->flags & CSS_NO_REF))
354 return percpu_ref_tryget_live(&css->refcnt);
355 return true;
356}
357
358/**
359 * css_is_dying - test whether the specified css is dying
360 * @css: target css
361 *
362 * Test whether @css is in the process of offlining or already offline. In
363 * most cases, ->css_online() and ->css_offline() callbacks should be
364 * enough; however, the actual offline operations are RCU delayed and this
365 * test returns %true also when @css is scheduled to be offlined.
366 *
367 * This is useful, for example, when the use case requires synchronous
368 * behavior with respect to cgroup removal. cgroup removal schedules css
369 * offlining but the css can seem alive while the operation is being
370 * delayed. If the delay affects user visible semantics, this test can be
371 * used to resolve the situation.
372 */
373static inline bool css_is_dying(struct cgroup_subsys_state *css)
374{
375 return !(css->flags & CSS_NO_REF) && percpu_ref_is_dying(&css->refcnt);
376}
377
378/**
379 * css_put - put a css reference
380 * @css: target css
381 *
382 * Put a reference obtained via css_get() and css_tryget_online().
383 */
384static inline void css_put(struct cgroup_subsys_state *css)
385{
386 if (!(css->flags & CSS_NO_REF))
387 percpu_ref_put(&css->refcnt);
388}
389
390/**
391 * css_put_many - put css references
392 * @css: target css
393 * @n: number of references to put
394 *
395 * Put references obtained via css_get() and css_tryget_online().
396 */
397static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n)
398{
399 if (!(css->flags & CSS_NO_REF))
400 percpu_ref_put_many(&css->refcnt, n);
401}
402
403static inline void cgroup_get(struct cgroup *cgrp)
404{
405 css_get(&cgrp->self);
406}
407
408static inline bool cgroup_tryget(struct cgroup *cgrp)
409{
410 return css_tryget(&cgrp->self);
411}
412
413static inline void cgroup_put(struct cgroup *cgrp)
414{
415 css_put(&cgrp->self);
416}
417
418/**
419 * task_css_set_check - obtain a task's css_set with extra access conditions
420 * @task: the task to obtain css_set for
421 * @__c: extra condition expression to be passed to rcu_dereference_check()
422 *
423 * A task's css_set is RCU protected, initialized and exited while holding
424 * task_lock(), and can only be modified while holding both cgroup_mutex
425 * and task_lock() while the task is alive. This macro verifies that the
426 * caller is inside proper critical section and returns @task's css_set.
427 *
428 * The caller can also specify additional allowed conditions via @__c, such
429 * as locks used during the cgroup_subsys::attach() methods.
430 */
431#ifdef CONFIG_PROVE_RCU
432extern struct mutex cgroup_mutex;
433extern spinlock_t css_set_lock;
434#define task_css_set_check(task, __c) \
435 rcu_dereference_check((task)->cgroups, \
436 lockdep_is_held(&cgroup_mutex) || \
437 lockdep_is_held(&css_set_lock) || \
438 ((task)->flags & PF_EXITING) || (__c))
439#else
440#define task_css_set_check(task, __c) \
441 rcu_dereference((task)->cgroups)
442#endif
443
444/**
445 * task_css_check - obtain css for (task, subsys) w/ extra access conds
446 * @task: the target task
447 * @subsys_id: the target subsystem ID
448 * @__c: extra condition expression to be passed to rcu_dereference_check()
449 *
450 * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The
451 * synchronization rules are the same as task_css_set_check().
452 */
453#define task_css_check(task, subsys_id, __c) \
454 task_css_set_check((task), (__c))->subsys[(subsys_id)]
455
456/**
457 * task_css_set - obtain a task's css_set
458 * @task: the task to obtain css_set for
459 *
460 * See task_css_set_check().
461 */
462static inline struct css_set *task_css_set(struct task_struct *task)
463{
464 return task_css_set_check(task, false);
465}
466
467/**
468 * task_css - obtain css for (task, subsys)
469 * @task: the target task
470 * @subsys_id: the target subsystem ID
471 *
472 * See task_css_check().
473 */
474static inline struct cgroup_subsys_state *task_css(struct task_struct *task,
475 int subsys_id)
476{
477 return task_css_check(task, subsys_id, false);
478}
479
480/**
481 * task_get_css - find and get the css for (task, subsys)
482 * @task: the target task
483 * @subsys_id: the target subsystem ID
484 *
485 * Find the css for the (@task, @subsys_id) combination, increment a
486 * reference on and return it. This function is guaranteed to return a
487 * valid css.
488 */
489static inline struct cgroup_subsys_state *
490task_get_css(struct task_struct *task, int subsys_id)
491{
492 struct cgroup_subsys_state *css;
493
494 rcu_read_lock();
495 while (true) {
496 css = task_css(task, subsys_id);
497 if (likely(css_tryget_online(css)))
498 break;
499 cpu_relax();
500 }
501 rcu_read_unlock();
502 return css;
503}
504
505/**
506 * task_css_is_root - test whether a task belongs to the root css
507 * @task: the target task
508 * @subsys_id: the target subsystem ID
509 *
510 * Test whether @task belongs to the root css on the specified subsystem.
511 * May be invoked in any context.
512 */
513static inline bool task_css_is_root(struct task_struct *task, int subsys_id)
514{
515 return task_css_check(task, subsys_id, true) ==
516 init_css_set.subsys[subsys_id];
517}
518
519static inline struct cgroup *task_cgroup(struct task_struct *task,
520 int subsys_id)
521{
522 return task_css(task, subsys_id)->cgroup;
523}
524
525static inline struct cgroup *task_dfl_cgroup(struct task_struct *task)
526{
527 return task_css_set(task)->dfl_cgrp;
528}
529
530static inline struct cgroup *cgroup_parent(struct cgroup *cgrp)
531{
532 struct cgroup_subsys_state *parent_css = cgrp->self.parent;
533
534 if (parent_css)
535 return container_of(parent_css, struct cgroup, self);
536 return NULL;
537}
538
539/**
540 * cgroup_is_descendant - test ancestry
541 * @cgrp: the cgroup to be tested
542 * @ancestor: possible ancestor of @cgrp
543 *
544 * Test whether @cgrp is a descendant of @ancestor. It also returns %true
545 * if @cgrp == @ancestor. This function is safe to call as long as @cgrp
546 * and @ancestor are accessible.
547 */
548static inline bool cgroup_is_descendant(struct cgroup *cgrp,
549 struct cgroup *ancestor)
550{
551 if (cgrp->root != ancestor->root || cgrp->level < ancestor->level)
552 return false;
553 return cgrp->ancestor_ids[ancestor->level] == ancestor->id;
554}
555
556/**
557 * cgroup_ancestor - find ancestor of cgroup
558 * @cgrp: cgroup to find ancestor of
559 * @ancestor_level: level of ancestor to find starting from root
560 *
561 * Find ancestor of cgroup at specified level starting from root if it exists
562 * and return pointer to it. Return NULL if @cgrp doesn't have ancestor at
563 * @ancestor_level.
564 *
565 * This function is safe to call as long as @cgrp is accessible.
566 */
567static inline struct cgroup *cgroup_ancestor(struct cgroup *cgrp,
568 int ancestor_level)
569{
570 struct cgroup *ptr;
571
572 if (cgrp->level < ancestor_level)
573 return NULL;
574
575 for (ptr = cgrp;
576 ptr && ptr->level > ancestor_level;
577 ptr = cgroup_parent(ptr))
578 ;
579
580 if (ptr && ptr->level == ancestor_level)
581 return ptr;
582
583 return NULL;
584}
585
586/**
587 * task_under_cgroup_hierarchy - test task's membership of cgroup ancestry
588 * @task: the task to be tested
589 * @ancestor: possible ancestor of @task's cgroup
590 *
591 * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor.
592 * It follows all the same rules as cgroup_is_descendant, and only applies
593 * to the default hierarchy.
594 */
595static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
596 struct cgroup *ancestor)
597{
598 struct css_set *cset = task_css_set(task);
599
600 return cgroup_is_descendant(cset->dfl_cgrp, ancestor);
601}
602
603/* no synchronization, the result can only be used as a hint */
604static inline bool cgroup_is_populated(struct cgroup *cgrp)
605{
606 return cgrp->nr_populated_csets + cgrp->nr_populated_domain_children +
607 cgrp->nr_populated_threaded_children;
608}
609
610/* returns ino associated with a cgroup */
611static inline ino_t cgroup_ino(struct cgroup *cgrp)
612{
613 return cgrp->kn->id.ino;
614}
615
616/* cft/css accessors for cftype->write() operation */
617static inline struct cftype *of_cft(struct kernfs_open_file *of)
618{
619 return of->kn->priv;
620}
621
622struct cgroup_subsys_state *of_css(struct kernfs_open_file *of);
623
624/* cft/css accessors for cftype->seq_*() operations */
625static inline struct cftype *seq_cft(struct seq_file *seq)
626{
627 return of_cft(seq->private);
628}
629
630static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq)
631{
632 return of_css(seq->private);
633}
634
635/*
636 * Name / path handling functions. All are thin wrappers around the kernfs
637 * counterparts and can be called under any context.
638 */
639
640static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen)
641{
642 return kernfs_name(cgrp->kn, buf, buflen);
643}
644
645static inline int cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen)
646{
647 return kernfs_path(cgrp->kn, buf, buflen);
648}
649
650static inline void pr_cont_cgroup_name(struct cgroup *cgrp)
651{
652 pr_cont_kernfs_name(cgrp->kn);
653}
654
655static inline void pr_cont_cgroup_path(struct cgroup *cgrp)
656{
657 pr_cont_kernfs_path(cgrp->kn);
658}
659
660static inline void cgroup_init_kthreadd(void)
661{
662 /*
663 * kthreadd is inherited by all kthreads, keep it in the root so
664 * that the new kthreads are guaranteed to stay in the root until
665 * initialization is finished.
666 */
667 current->no_cgroup_migration = 1;
668}
669
670static inline void cgroup_kthread_ready(void)
671{
672 /*
673 * This kthread finished initialization. The creator should have
674 * set PF_NO_SETAFFINITY if this kthread should stay in the root.
675 */
676 current->no_cgroup_migration = 0;
677}
678
679static inline union kernfs_node_id *cgroup_get_kernfs_id(struct cgroup *cgrp)
680{
681 return &cgrp->kn->id;
682}
683
684void cgroup_path_from_kernfs_id(const union kernfs_node_id *id,
685 char *buf, size_t buflen);
686#else /* !CONFIG_CGROUPS */
687
688struct cgroup_subsys_state;
689struct cgroup;
690
691static inline void css_put(struct cgroup_subsys_state *css) {}
692static inline int cgroup_attach_task_all(struct task_struct *from,
693 struct task_struct *t) { return 0; }
694static inline int cgroupstats_build(struct cgroupstats *stats,
695 struct dentry *dentry) { return -EINVAL; }
696
697static inline void cgroup_fork(struct task_struct *p) {}
698static inline int cgroup_can_fork(struct task_struct *p) { return 0; }
699static inline void cgroup_cancel_fork(struct task_struct *p) {}
700static inline void cgroup_post_fork(struct task_struct *p) {}
701static inline void cgroup_exit(struct task_struct *p) {}
702static inline void cgroup_free(struct task_struct *p) {}
703
704static inline int cgroup_init_early(void) { return 0; }
705static inline int cgroup_init(void) { return 0; }
706static inline void cgroup_init_kthreadd(void) {}
707static inline void cgroup_kthread_ready(void) {}
708static inline union kernfs_node_id *cgroup_get_kernfs_id(struct cgroup *cgrp)
709{
710 return NULL;
711}
712
713static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
714 struct cgroup *ancestor)
715{
716 return true;
717}
718
719static inline void cgroup_path_from_kernfs_id(const union kernfs_node_id *id,
720 char *buf, size_t buflen) {}
721#endif /* !CONFIG_CGROUPS */
722
723#ifdef CONFIG_CGROUPS
724/*
725 * cgroup scalable recursive statistics.
726 */
727void cgroup_rstat_updated(struct cgroup *cgrp, int cpu);
728void cgroup_rstat_flush(struct cgroup *cgrp);
729void cgroup_rstat_flush_irqsafe(struct cgroup *cgrp);
730void cgroup_rstat_flush_hold(struct cgroup *cgrp);
731void cgroup_rstat_flush_release(void);
732
733/*
734 * Basic resource stats.
735 */
736#ifdef CONFIG_CGROUP_CPUACCT
737void cpuacct_charge(struct task_struct *tsk, u64 cputime);
738void cpuacct_account_field(struct task_struct *tsk, int index, u64 val);
739#else
740static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
741static inline void cpuacct_account_field(struct task_struct *tsk, int index,
742 u64 val) {}
743#endif
744
745void __cgroup_account_cputime(struct cgroup *cgrp, u64 delta_exec);
746void __cgroup_account_cputime_field(struct cgroup *cgrp,
747 enum cpu_usage_stat index, u64 delta_exec);
748
749static inline void cgroup_account_cputime(struct task_struct *task,
750 u64 delta_exec)
751{
752 struct cgroup *cgrp;
753
754 cpuacct_charge(task, delta_exec);
755
756 rcu_read_lock();
757 cgrp = task_dfl_cgroup(task);
758 if (cgroup_parent(cgrp))
759 __cgroup_account_cputime(cgrp, delta_exec);
760 rcu_read_unlock();
761}
762
763static inline void cgroup_account_cputime_field(struct task_struct *task,
764 enum cpu_usage_stat index,
765 u64 delta_exec)
766{
767 struct cgroup *cgrp;
768
769 cpuacct_account_field(task, index, delta_exec);
770
771 rcu_read_lock();
772 cgrp = task_dfl_cgroup(task);
773 if (cgroup_parent(cgrp))
774 __cgroup_account_cputime_field(cgrp, index, delta_exec);
775 rcu_read_unlock();
776}
777
778#else /* CONFIG_CGROUPS */
779
780static inline void cgroup_account_cputime(struct task_struct *task,
781 u64 delta_exec) {}
782static inline void cgroup_account_cputime_field(struct task_struct *task,
783 enum cpu_usage_stat index,
784 u64 delta_exec) {}
785
786#endif /* CONFIG_CGROUPS */
787
788/*
789 * sock->sk_cgrp_data handling. For more info, see sock_cgroup_data
790 * definition in cgroup-defs.h.
791 */
792#ifdef CONFIG_SOCK_CGROUP_DATA
793
794#if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID)
795extern spinlock_t cgroup_sk_update_lock;
796#endif
797
798void cgroup_sk_alloc_disable(void);
799void cgroup_sk_alloc(struct sock_cgroup_data *skcd);
800void cgroup_sk_free(struct sock_cgroup_data *skcd);
801
802static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd)
803{
804#if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID)
805 unsigned long v;
806
807 /*
808 * @skcd->val is 64bit but the following is safe on 32bit too as we
809 * just need the lower ulong to be written and read atomically.
810 */
811 v = READ_ONCE(skcd->val);
812
813 if (v & 1)
814 return &cgrp_dfl_root.cgrp;
815
816 return (struct cgroup *)(unsigned long)v ?: &cgrp_dfl_root.cgrp;
817#else
818 return (struct cgroup *)(unsigned long)skcd->val;
819#endif
820}
821
822#else /* CONFIG_CGROUP_DATA */
823
824static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {}
825static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {}
826
827#endif /* CONFIG_CGROUP_DATA */
828
829struct cgroup_namespace {
830 refcount_t count;
831 struct ns_common ns;
832 struct user_namespace *user_ns;
833 struct ucounts *ucounts;
834 struct css_set *root_cset;
835};
836
837extern struct cgroup_namespace init_cgroup_ns;
838
839#ifdef CONFIG_CGROUPS
840
841void free_cgroup_ns(struct cgroup_namespace *ns);
842
843struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,
844 struct user_namespace *user_ns,
845 struct cgroup_namespace *old_ns);
846
847int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
848 struct cgroup_namespace *ns);
849
850#else /* !CONFIG_CGROUPS */
851
852static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
853static inline struct cgroup_namespace *
854copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
855 struct cgroup_namespace *old_ns)
856{
857 return old_ns;
858}
859
860#endif /* !CONFIG_CGROUPS */
861
862static inline void get_cgroup_ns(struct cgroup_namespace *ns)
863{
864 if (ns)
865 refcount_inc(&ns->count);
866}
867
868static inline void put_cgroup_ns(struct cgroup_namespace *ns)
869{
870 if (ns && refcount_dec_and_test(&ns->count))
871 free_cgroup_ns(ns);
872}
873
874#endif /* _LINUX_CGROUP_H */
875