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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 : : /* internal flags */
47 : : #define CSS_TASK_ITER_SKIPPED (1U << 16)
48 : :
49 : : /* a css_task_iter should be treated as an opaque object */
50 : : struct css_task_iter {
51 : : struct cgroup_subsys *ss;
52 : : unsigned int flags;
53 : :
54 : : struct list_head *cset_pos;
55 : : struct list_head *cset_head;
56 : :
57 : : struct list_head *tcset_pos;
58 : : struct list_head *tcset_head;
59 : :
60 : : struct list_head *task_pos;
61 : : struct list_head *tasks_head;
62 : : struct list_head *mg_tasks_head;
63 : : struct list_head *dying_tasks_head;
64 : :
65 : : struct list_head *cur_tasks_head;
66 : : struct css_set *cur_cset;
67 : : struct css_set *cur_dcset;
68 : : struct task_struct *cur_task;
69 : : struct list_head iters_node; /* css_set->task_iters */
70 : : };
71 : :
72 : : extern struct cgroup_root cgrp_dfl_root;
73 : : extern struct css_set init_css_set;
74 : :
75 : : #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys;
76 : : #include <linux/cgroup_subsys.h>
77 : : #undef SUBSYS
78 : :
79 : : #define SUBSYS(_x) \
80 : : extern struct static_key_true _x ## _cgrp_subsys_enabled_key; \
81 : : extern struct static_key_true _x ## _cgrp_subsys_on_dfl_key;
82 : : #include <linux/cgroup_subsys.h>
83 : : #undef SUBSYS
84 : :
85 : : /**
86 : : * cgroup_subsys_enabled - fast test on whether a subsys is enabled
87 : : * @ss: subsystem in question
88 : : */
89 : : #define cgroup_subsys_enabled(ss) \
90 : : static_branch_likely(&ss ## _enabled_key)
91 : :
92 : : /**
93 : : * cgroup_subsys_on_dfl - fast test on whether a subsys is on default hierarchy
94 : : * @ss: subsystem in question
95 : : */
96 : : #define cgroup_subsys_on_dfl(ss) \
97 : : static_branch_likely(&ss ## _on_dfl_key)
98 : :
99 : : bool css_has_online_children(struct cgroup_subsys_state *css);
100 : : struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss);
101 : : struct cgroup_subsys_state *cgroup_e_css(struct cgroup *cgroup,
102 : : struct cgroup_subsys *ss);
103 : : struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgroup,
104 : : struct cgroup_subsys *ss);
105 : : struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
106 : : struct cgroup_subsys *ss);
107 : :
108 : : struct cgroup *cgroup_get_from_path(const char *path);
109 : : struct cgroup *cgroup_get_from_fd(int fd);
110 : :
111 : : int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);
112 : : int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
113 : :
114 : : int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
115 : : int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
116 : : int cgroup_rm_cftypes(struct cftype *cfts);
117 : : void cgroup_file_notify(struct cgroup_file *cfile);
118 : :
119 : : int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);
120 : : int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry);
121 : : int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
122 : : struct pid *pid, struct task_struct *tsk);
123 : :
124 : : void cgroup_fork(struct task_struct *p);
125 : : extern int cgroup_can_fork(struct task_struct *p);
126 : : extern void cgroup_cancel_fork(struct task_struct *p);
127 : : extern void cgroup_post_fork(struct task_struct *p);
128 : : void cgroup_exit(struct task_struct *p);
129 : : void cgroup_release(struct task_struct *p);
130 : : void cgroup_free(struct task_struct *p);
131 : :
132 : : int cgroup_init_early(void);
133 : : int cgroup_init(void);
134 : :
135 : : int cgroup_parse_float(const char *input, unsigned dec_shift, s64 *v);
136 : :
137 : : /*
138 : : * Iteration helpers and macros.
139 : : */
140 : :
141 : : struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos,
142 : : struct cgroup_subsys_state *parent);
143 : : struct cgroup_subsys_state *css_next_descendant_pre(struct cgroup_subsys_state *pos,
144 : : struct cgroup_subsys_state *css);
145 : : struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state *pos);
146 : : struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos,
147 : : struct cgroup_subsys_state *css);
148 : :
149 : : struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset,
150 : : struct cgroup_subsys_state **dst_cssp);
151 : : struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset,
152 : : struct cgroup_subsys_state **dst_cssp);
153 : :
154 : : void cgroup_enable_task_cg_lists(void);
155 : : void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags,
156 : : struct css_task_iter *it);
157 : : struct task_struct *css_task_iter_next(struct css_task_iter *it);
158 : : void css_task_iter_end(struct css_task_iter *it);
159 : :
160 : : /**
161 : : * css_for_each_child - iterate through children of a css
162 : : * @pos: the css * to use as the loop cursor
163 : : * @parent: css whose children to walk
164 : : *
165 : : * Walk @parent's children. Must be called under rcu_read_lock().
166 : : *
167 : : * If a subsystem synchronizes ->css_online() and the start of iteration, a
168 : : * css which finished ->css_online() is guaranteed to be visible in the
169 : : * future iterations and will stay visible until the last reference is put.
170 : : * A css which hasn't finished ->css_online() or already finished
171 : : * ->css_offline() may show up during traversal. It's each subsystem's
172 : : * responsibility to synchronize against on/offlining.
173 : : *
174 : : * It is allowed to temporarily drop RCU read lock during iteration. The
175 : : * caller is responsible for ensuring that @pos remains accessible until
176 : : * the start of the next iteration by, for example, bumping the css refcnt.
177 : : */
178 : : #define css_for_each_child(pos, parent) \
179 : : for ((pos) = css_next_child(NULL, (parent)); (pos); \
180 : : (pos) = css_next_child((pos), (parent)))
181 : :
182 : : /**
183 : : * css_for_each_descendant_pre - pre-order walk of a css's descendants
184 : : * @pos: the css * to use as the loop cursor
185 : : * @root: css whose descendants to walk
186 : : *
187 : : * Walk @root's descendants. @root is included in the iteration and the
188 : : * first node to be visited. Must be called under rcu_read_lock().
189 : : *
190 : : * If a subsystem synchronizes ->css_online() and the start of iteration, a
191 : : * css which finished ->css_online() is guaranteed to be visible in the
192 : : * future iterations and will stay visible until the last reference is put.
193 : : * A css which hasn't finished ->css_online() or already finished
194 : : * ->css_offline() may show up during traversal. It's each subsystem's
195 : : * responsibility to synchronize against on/offlining.
196 : : *
197 : : * For example, the following guarantees that a descendant can't escape
198 : : * state updates of its ancestors.
199 : : *
200 : : * my_online(@css)
201 : : * {
202 : : * Lock @css's parent and @css;
203 : : * Inherit state from the parent;
204 : : * Unlock both.
205 : : * }
206 : : *
207 : : * my_update_state(@css)
208 : : * {
209 : : * css_for_each_descendant_pre(@pos, @css) {
210 : : * Lock @pos;
211 : : * if (@pos == @css)
212 : : * Update @css's state;
213 : : * else
214 : : * Verify @pos is alive and inherit state from its parent;
215 : : * Unlock @pos;
216 : : * }
217 : : * }
218 : : *
219 : : * As long as the inheriting step, including checking the parent state, is
220 : : * enclosed inside @pos locking, double-locking the parent isn't necessary
221 : : * while inheriting. The state update to the parent is guaranteed to be
222 : : * visible by walking order and, as long as inheriting operations to the
223 : : * same @pos are atomic to each other, multiple updates racing each other
224 : : * still result in the correct state. It's guaranateed that at least one
225 : : * inheritance happens for any css after the latest update to its parent.
226 : : *
227 : : * If checking parent's state requires locking the parent, each inheriting
228 : : * iteration should lock and unlock both @pos->parent and @pos.
229 : : *
230 : : * Alternatively, a subsystem may choose to use a single global lock to
231 : : * synchronize ->css_online() and ->css_offline() against tree-walking
232 : : * operations.
233 : : *
234 : : * It is allowed to temporarily drop RCU read lock during iteration. The
235 : : * caller is responsible for ensuring that @pos remains accessible until
236 : : * the start of the next iteration by, for example, bumping the css refcnt.
237 : : */
238 : : #define css_for_each_descendant_pre(pos, css) \
239 : : for ((pos) = css_next_descendant_pre(NULL, (css)); (pos); \
240 : : (pos) = css_next_descendant_pre((pos), (css)))
241 : :
242 : : /**
243 : : * css_for_each_descendant_post - post-order walk of a css's descendants
244 : : * @pos: the css * to use as the loop cursor
245 : : * @css: css whose descendants to walk
246 : : *
247 : : * Similar to css_for_each_descendant_pre() but performs post-order
248 : : * traversal instead. @root is included in the iteration and the last
249 : : * node to be visited.
250 : : *
251 : : * If a subsystem synchronizes ->css_online() and the start of iteration, a
252 : : * css which finished ->css_online() is guaranteed to be visible in the
253 : : * future iterations and will stay visible until the last reference is put.
254 : : * A css which hasn't finished ->css_online() or already finished
255 : : * ->css_offline() may show up during traversal. It's each subsystem's
256 : : * responsibility to synchronize against on/offlining.
257 : : *
258 : : * Note that the walk visibility guarantee example described in pre-order
259 : : * walk doesn't apply the same to post-order walks.
260 : : */
261 : : #define css_for_each_descendant_post(pos, css) \
262 : : for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \
263 : : (pos) = css_next_descendant_post((pos), (css)))
264 : :
265 : : /**
266 : : * cgroup_taskset_for_each - iterate cgroup_taskset
267 : : * @task: the loop cursor
268 : : * @dst_css: the destination css
269 : : * @tset: taskset to iterate
270 : : *
271 : : * @tset may contain multiple tasks and they may belong to multiple
272 : : * processes.
273 : : *
274 : : * On the v2 hierarchy, there may be tasks from multiple processes and they
275 : : * may not share the source or destination csses.
276 : : *
277 : : * On traditional hierarchies, when there are multiple tasks in @tset, if a
278 : : * task of a process is in @tset, all tasks of the process are in @tset.
279 : : * Also, all are guaranteed to share the same source and destination csses.
280 : : *
281 : : * Iteration is not in any specific order.
282 : : */
283 : : #define cgroup_taskset_for_each(task, dst_css, tset) \
284 : : for ((task) = cgroup_taskset_first((tset), &(dst_css)); \
285 : : (task); \
286 : : (task) = cgroup_taskset_next((tset), &(dst_css)))
287 : :
288 : : /**
289 : : * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset
290 : : * @leader: the loop cursor
291 : : * @dst_css: the destination css
292 : : * @tset: taskset to iterate
293 : : *
294 : : * Iterate threadgroup leaders of @tset. For single-task migrations, @tset
295 : : * may not contain any.
296 : : */
297 : : #define cgroup_taskset_for_each_leader(leader, dst_css, tset) \
298 : : for ((leader) = cgroup_taskset_first((tset), &(dst_css)); \
299 : : (leader); \
300 : : (leader) = cgroup_taskset_next((tset), &(dst_css))) \
301 : : if ((leader) != (leader)->group_leader) \
302 : : ; \
303 : : else
304 : :
305 : : /*
306 : : * Inline functions.
307 : : */
308 : :
309 : : /**
310 : : * css_get - obtain a reference on the specified css
311 : : * @css: target css
312 : : *
313 : : * The caller must already have a reference.
314 : : */
315 : : static inline void css_get(struct cgroup_subsys_state *css)
316 : : {
317 : 3 : if (!(css->flags & CSS_NO_REF))
318 : 3 : percpu_ref_get(&css->refcnt);
319 : : }
320 : :
321 : : /**
322 : : * css_get_many - obtain references on the specified css
323 : : * @css: target css
324 : : * @n: number of references to get
325 : : *
326 : : * The caller must already have a reference.
327 : : */
328 : : static inline void css_get_many(struct cgroup_subsys_state *css, unsigned int n)
329 : : {
330 : 0 : if (!(css->flags & CSS_NO_REF))
331 : 0 : percpu_ref_get_many(&css->refcnt, n);
332 : : }
333 : :
334 : : /**
335 : : * css_tryget - try to obtain a reference on the specified css
336 : : * @css: target css
337 : : *
338 : : * Obtain a reference on @css unless it already has reached zero and is
339 : : * being released. This function doesn't care whether @css is on or
340 : : * offline. The caller naturally needs to ensure that @css is accessible
341 : : * but doesn't have to be holding a reference on it - IOW, RCU protected
342 : : * access is good enough for this function. Returns %true if a reference
343 : : * count was successfully obtained; %false otherwise.
344 : : */
345 : : static inline bool css_tryget(struct cgroup_subsys_state *css)
346 : : {
347 : 3 : if (!(css->flags & CSS_NO_REF))
348 : 3 : return percpu_ref_tryget(&css->refcnt);
349 : : return true;
350 : : }
351 : :
352 : : /**
353 : : * css_tryget_online - try to obtain a reference on the specified css if online
354 : : * @css: target css
355 : : *
356 : : * Obtain a reference on @css if it's online. The caller naturally needs
357 : : * to ensure that @css is accessible but doesn't have to be holding a
358 : : * reference on it - IOW, RCU protected access is good enough for this
359 : : * function. Returns %true if a reference count was successfully obtained;
360 : : * %false otherwise.
361 : : */
362 : 0 : static inline bool css_tryget_online(struct cgroup_subsys_state *css)
363 : : {
364 : 3 : if (!(css->flags & CSS_NO_REF))
365 : 3 : return percpu_ref_tryget_live(&css->refcnt);
366 : : return true;
367 : : }
368 : :
369 : : /**
370 : : * css_is_dying - test whether the specified css is dying
371 : : * @css: target css
372 : : *
373 : : * Test whether @css is in the process of offlining or already offline. In
374 : : * most cases, ->css_online() and ->css_offline() callbacks should be
375 : : * enough; however, the actual offline operations are RCU delayed and this
376 : : * test returns %true also when @css is scheduled to be offlined.
377 : : *
378 : : * This is useful, for example, when the use case requires synchronous
379 : : * behavior with respect to cgroup removal. cgroup removal schedules css
380 : : * offlining but the css can seem alive while the operation is being
381 : : * delayed. If the delay affects user visible semantics, this test can be
382 : : * used to resolve the situation.
383 : : */
384 : : static inline bool css_is_dying(struct cgroup_subsys_state *css)
385 : : {
386 : 0 : return !(css->flags & CSS_NO_REF) && percpu_ref_is_dying(&css->refcnt);
387 : : }
388 : :
389 : : /**
390 : : * css_put - put a css reference
391 : : * @css: target css
392 : : *
393 : : * Put a reference obtained via css_get() and css_tryget_online().
394 : : */
395 : 0 : static inline void css_put(struct cgroup_subsys_state *css)
396 : : {
397 : 3 : if (!(css->flags & CSS_NO_REF))
398 : 3 : percpu_ref_put(&css->refcnt);
399 : 0 : }
400 : :
401 : : /**
402 : : * css_put_many - put css references
403 : : * @css: target css
404 : : * @n: number of references to put
405 : : *
406 : : * Put references obtained via css_get() and css_tryget_online().
407 : : */
408 : 0 : static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n)
409 : : {
410 : 0 : if (!(css->flags & CSS_NO_REF))
411 : 0 : percpu_ref_put_many(&css->refcnt, n);
412 : 0 : }
413 : :
414 : : static inline void cgroup_get(struct cgroup *cgrp)
415 : : {
416 : : css_get(&cgrp->self);
417 : : }
418 : :
419 : : static inline bool cgroup_tryget(struct cgroup *cgrp)
420 : : {
421 : : return css_tryget(&cgrp->self);
422 : : }
423 : :
424 : : static inline void cgroup_put(struct cgroup *cgrp)
425 : : {
426 : : css_put(&cgrp->self);
427 : : }
428 : :
429 : : /**
430 : : * task_css_set_check - obtain a task's css_set with extra access conditions
431 : : * @task: the task to obtain css_set for
432 : : * @__c: extra condition expression to be passed to rcu_dereference_check()
433 : : *
434 : : * A task's css_set is RCU protected, initialized and exited while holding
435 : : * task_lock(), and can only be modified while holding both cgroup_mutex
436 : : * and task_lock() while the task is alive. This macro verifies that the
437 : : * caller is inside proper critical section and returns @task's css_set.
438 : : *
439 : : * The caller can also specify additional allowed conditions via @__c, such
440 : : * as locks used during the cgroup_subsys::attach() methods.
441 : : */
442 : : #ifdef CONFIG_PROVE_RCU
443 : : extern struct mutex cgroup_mutex;
444 : : extern spinlock_t css_set_lock;
445 : : #define task_css_set_check(task, __c) \
446 : : rcu_dereference_check((task)->cgroups, \
447 : : lockdep_is_held(&cgroup_mutex) || \
448 : : lockdep_is_held(&css_set_lock) || \
449 : : ((task)->flags & PF_EXITING) || (__c))
450 : : #else
451 : : #define task_css_set_check(task, __c) \
452 : : rcu_dereference((task)->cgroups)
453 : : #endif
454 : :
455 : : /**
456 : : * task_css_check - obtain css for (task, subsys) w/ extra access conds
457 : : * @task: the target task
458 : : * @subsys_id: the target subsystem ID
459 : : * @__c: extra condition expression to be passed to rcu_dereference_check()
460 : : *
461 : : * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The
462 : : * synchronization rules are the same as task_css_set_check().
463 : : */
464 : : #define task_css_check(task, subsys_id, __c) \
465 : : task_css_set_check((task), (__c))->subsys[(subsys_id)]
466 : :
467 : : /**
468 : : * task_css_set - obtain a task's css_set
469 : : * @task: the task to obtain css_set for
470 : : *
471 : : * See task_css_set_check().
472 : : */
473 : : static inline struct css_set *task_css_set(struct task_struct *task)
474 : : {
475 : 3 : return task_css_set_check(task, false);
476 : : }
477 : :
478 : : /**
479 : : * task_css - obtain css for (task, subsys)
480 : : * @task: the target task
481 : : * @subsys_id: the target subsystem ID
482 : : *
483 : : * See task_css_check().
484 : : */
485 : : static inline struct cgroup_subsys_state *task_css(struct task_struct *task,
486 : : int subsys_id)
487 : : {
488 : 3 : return task_css_check(task, subsys_id, false);
489 : : }
490 : :
491 : : /**
492 : : * task_get_css - find and get the css for (task, subsys)
493 : : * @task: the target task
494 : : * @subsys_id: the target subsystem ID
495 : : *
496 : : * Find the css for the (@task, @subsys_id) combination, increment a
497 : : * reference on and return it. This function is guaranteed to return a
498 : : * valid css. The returned css may already have been offlined.
499 : : */
500 : : static inline struct cgroup_subsys_state *
501 : 1 : task_get_css(struct task_struct *task, int subsys_id)
502 : : {
503 : : struct cgroup_subsys_state *css;
504 : :
505 : : rcu_read_lock();
506 : : while (true) {
507 : : css = task_css(task, subsys_id);
508 : : /*
509 : : * Can't use css_tryget_online() here. A task which has
510 : : * PF_EXITING set may stay associated with an offline css.
511 : : * If such task calls this function, css_tryget_online()
512 : : * will keep failing.
513 : : */
514 : 1 : if (likely(css_tryget(css)))
515 : : break;
516 : 0 : cpu_relax();
517 : 0 : }
518 : : rcu_read_unlock();
519 : 1 : return css;
520 : : }
521 : :
522 : : /**
523 : : * task_css_is_root - test whether a task belongs to the root css
524 : : * @task: the target task
525 : : * @subsys_id: the target subsystem ID
526 : : *
527 : : * Test whether @task belongs to the root css on the specified subsystem.
528 : : * May be invoked in any context.
529 : : */
530 : : static inline bool task_css_is_root(struct task_struct *task, int subsys_id)
531 : : {
532 : 3 : return task_css_check(task, subsys_id, true) ==
533 : 3 : init_css_set.subsys[subsys_id];
534 : : }
535 : :
536 : : static inline struct cgroup *task_cgroup(struct task_struct *task,
537 : : int subsys_id)
538 : : {
539 : 0 : return task_css(task, subsys_id)->cgroup;
540 : : }
541 : :
542 : 0 : static inline struct cgroup *task_dfl_cgroup(struct task_struct *task)
543 : : {
544 : 3 : return task_css_set(task)->dfl_cgrp;
545 : : }
546 : :
547 : : static inline struct cgroup *cgroup_parent(struct cgroup *cgrp)
548 : : {
549 : 3 : struct cgroup_subsys_state *parent_css = cgrp->self.parent;
550 : :
551 : 3 : if (parent_css)
552 : : return container_of(parent_css, struct cgroup, self);
553 : : return NULL;
554 : : }
555 : :
556 : : /**
557 : : * cgroup_is_descendant - test ancestry
558 : : * @cgrp: the cgroup to be tested
559 : : * @ancestor: possible ancestor of @cgrp
560 : : *
561 : : * Test whether @cgrp is a descendant of @ancestor. It also returns %true
562 : : * if @cgrp == @ancestor. This function is safe to call as long as @cgrp
563 : : * and @ancestor are accessible.
564 : : */
565 : : static inline bool cgroup_is_descendant(struct cgroup *cgrp,
566 : : struct cgroup *ancestor)
567 : : {
568 : 3 : if (cgrp->root != ancestor->root || cgrp->level < ancestor->level)
569 : : return false;
570 : 3 : return cgrp->ancestor_ids[ancestor->level] == ancestor->id;
571 : : }
572 : :
573 : : /**
574 : : * cgroup_ancestor - find ancestor of cgroup
575 : : * @cgrp: cgroup to find ancestor of
576 : : * @ancestor_level: level of ancestor to find starting from root
577 : : *
578 : : * Find ancestor of cgroup at specified level starting from root if it exists
579 : : * and return pointer to it. Return NULL if @cgrp doesn't have ancestor at
580 : : * @ancestor_level.
581 : : *
582 : : * This function is safe to call as long as @cgrp is accessible.
583 : : */
584 : 0 : static inline struct cgroup *cgroup_ancestor(struct cgroup *cgrp,
585 : : int ancestor_level)
586 : : {
587 : 0 : if (cgrp->level < ancestor_level)
588 : : return NULL;
589 : 0 : while (cgrp && cgrp->level > ancestor_level)
590 : : cgrp = cgroup_parent(cgrp);
591 : 0 : return cgrp;
592 : : }
593 : :
594 : : /**
595 : : * task_under_cgroup_hierarchy - test task's membership of cgroup ancestry
596 : : * @task: the task to be tested
597 : : * @ancestor: possible ancestor of @task's cgroup
598 : : *
599 : : * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor.
600 : : * It follows all the same rules as cgroup_is_descendant, and only applies
601 : : * to the default hierarchy.
602 : : */
603 : 0 : static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
604 : : struct cgroup *ancestor)
605 : : {
606 : : struct css_set *cset = task_css_set(task);
607 : :
608 : 0 : return cgroup_is_descendant(cset->dfl_cgrp, ancestor);
609 : : }
610 : :
611 : : /* no synchronization, the result can only be used as a hint */
612 : : static inline bool cgroup_is_populated(struct cgroup *cgrp)
613 : : {
614 : 3 : return cgrp->nr_populated_csets + cgrp->nr_populated_domain_children +
615 : 3 : cgrp->nr_populated_threaded_children;
616 : : }
617 : :
618 : : /* returns ino associated with a cgroup */
619 : : static inline ino_t cgroup_ino(struct cgroup *cgrp)
620 : : {
621 : 0 : return cgrp->kn->id.ino;
622 : : }
623 : :
624 : : /* cft/css accessors for cftype->write() operation */
625 : : static inline struct cftype *of_cft(struct kernfs_open_file *of)
626 : : {
627 : 3 : return of->kn->priv;
628 : : }
629 : :
630 : : struct cgroup_subsys_state *of_css(struct kernfs_open_file *of);
631 : :
632 : : /* cft/css accessors for cftype->seq_*() operations */
633 : : static inline struct cftype *seq_cft(struct seq_file *seq)
634 : : {
635 : 3 : return of_cft(seq->private);
636 : : }
637 : :
638 : : static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq)
639 : : {
640 : 3 : return of_css(seq->private);
641 : : }
642 : :
643 : : /*
644 : : * Name / path handling functions. All are thin wrappers around the kernfs
645 : : * counterparts and can be called under any context.
646 : : */
647 : :
648 : : static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen)
649 : : {
650 : 0 : return kernfs_name(cgrp->kn, buf, buflen);
651 : : }
652 : :
653 : : static inline int cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen)
654 : : {
655 : 0 : return kernfs_path(cgrp->kn, buf, buflen);
656 : : }
657 : :
658 : : static inline void pr_cont_cgroup_name(struct cgroup *cgrp)
659 : : {
660 : 0 : pr_cont_kernfs_name(cgrp->kn);
661 : : }
662 : :
663 : : static inline void pr_cont_cgroup_path(struct cgroup *cgrp)
664 : : {
665 : 0 : pr_cont_kernfs_path(cgrp->kn);
666 : : }
667 : :
668 : : static inline struct psi_group *cgroup_psi(struct cgroup *cgrp)
669 : : {
670 : : return &cgrp->psi;
671 : : }
672 : :
673 : : static inline void cgroup_init_kthreadd(void)
674 : : {
675 : : /*
676 : : * kthreadd is inherited by all kthreads, keep it in the root so
677 : : * that the new kthreads are guaranteed to stay in the root until
678 : : * initialization is finished.
679 : : */
680 : 3 : current->no_cgroup_migration = 1;
681 : : }
682 : :
683 : : static inline void cgroup_kthread_ready(void)
684 : : {
685 : : /*
686 : : * This kthread finished initialization. The creator should have
687 : : * set PF_NO_SETAFFINITY if this kthread should stay in the root.
688 : : */
689 : 3 : current->no_cgroup_migration = 0;
690 : : }
691 : :
692 : : static inline union kernfs_node_id *cgroup_get_kernfs_id(struct cgroup *cgrp)
693 : : {
694 : 0 : return &cgrp->kn->id;
695 : : }
696 : :
697 : : void cgroup_path_from_kernfs_id(const union kernfs_node_id *id,
698 : : char *buf, size_t buflen);
699 : : #else /* !CONFIG_CGROUPS */
700 : :
701 : : struct cgroup_subsys_state;
702 : : struct cgroup;
703 : :
704 : : static inline void css_get(struct cgroup_subsys_state *css) {}
705 : : static inline void css_put(struct cgroup_subsys_state *css) {}
706 : : static inline int cgroup_attach_task_all(struct task_struct *from,
707 : : struct task_struct *t) { return 0; }
708 : : static inline int cgroupstats_build(struct cgroupstats *stats,
709 : : struct dentry *dentry) { return -EINVAL; }
710 : :
711 : : static inline void cgroup_fork(struct task_struct *p) {}
712 : : static inline int cgroup_can_fork(struct task_struct *p) { return 0; }
713 : : static inline void cgroup_cancel_fork(struct task_struct *p) {}
714 : : static inline void cgroup_post_fork(struct task_struct *p) {}
715 : : static inline void cgroup_exit(struct task_struct *p) {}
716 : : static inline void cgroup_release(struct task_struct *p) {}
717 : : static inline void cgroup_free(struct task_struct *p) {}
718 : :
719 : : static inline int cgroup_init_early(void) { return 0; }
720 : : static inline int cgroup_init(void) { return 0; }
721 : : static inline void cgroup_init_kthreadd(void) {}
722 : : static inline void cgroup_kthread_ready(void) {}
723 : : static inline union kernfs_node_id *cgroup_get_kernfs_id(struct cgroup *cgrp)
724 : : {
725 : : return NULL;
726 : : }
727 : :
728 : : static inline struct cgroup *cgroup_parent(struct cgroup *cgrp)
729 : : {
730 : : return NULL;
731 : : }
732 : :
733 : : static inline struct psi_group *cgroup_psi(struct cgroup *cgrp)
734 : : {
735 : : return NULL;
736 : : }
737 : :
738 : : static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
739 : : struct cgroup *ancestor)
740 : : {
741 : : return true;
742 : : }
743 : :
744 : : static inline void cgroup_path_from_kernfs_id(const union kernfs_node_id *id,
745 : : char *buf, size_t buflen) {}
746 : : #endif /* !CONFIG_CGROUPS */
747 : :
748 : : #ifdef CONFIG_CGROUPS
749 : : /*
750 : : * cgroup scalable recursive statistics.
751 : : */
752 : : void cgroup_rstat_updated(struct cgroup *cgrp, int cpu);
753 : : void cgroup_rstat_flush(struct cgroup *cgrp);
754 : : void cgroup_rstat_flush_irqsafe(struct cgroup *cgrp);
755 : : void cgroup_rstat_flush_hold(struct cgroup *cgrp);
756 : : void cgroup_rstat_flush_release(void);
757 : :
758 : : /*
759 : : * Basic resource stats.
760 : : */
761 : : #ifdef CONFIG_CGROUP_CPUACCT
762 : : void cpuacct_charge(struct task_struct *tsk, u64 cputime);
763 : : void cpuacct_account_field(struct task_struct *tsk, int index, u64 val);
764 : : #else
765 : : static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
766 : : static inline void cpuacct_account_field(struct task_struct *tsk, int index,
767 : : u64 val) {}
768 : : #endif
769 : :
770 : : void __cgroup_account_cputime(struct cgroup *cgrp, u64 delta_exec);
771 : : void __cgroup_account_cputime_field(struct cgroup *cgrp,
772 : : enum cpu_usage_stat index, u64 delta_exec);
773 : :
774 : 3 : static inline void cgroup_account_cputime(struct task_struct *task,
775 : : u64 delta_exec)
776 : : {
777 : : struct cgroup *cgrp;
778 : :
779 : 3 : cpuacct_charge(task, delta_exec);
780 : :
781 : : rcu_read_lock();
782 : : cgrp = task_dfl_cgroup(task);
783 : 3 : if (cgroup_parent(cgrp))
784 : 3 : __cgroup_account_cputime(cgrp, delta_exec);
785 : : rcu_read_unlock();
786 : 3 : }
787 : :
788 : 3 : static inline void cgroup_account_cputime_field(struct task_struct *task,
789 : : enum cpu_usage_stat index,
790 : : u64 delta_exec)
791 : : {
792 : : struct cgroup *cgrp;
793 : :
794 : 3 : cpuacct_account_field(task, index, delta_exec);
795 : :
796 : : rcu_read_lock();
797 : : cgrp = task_dfl_cgroup(task);
798 : 3 : if (cgroup_parent(cgrp))
799 : 3 : __cgroup_account_cputime_field(cgrp, index, delta_exec);
800 : : rcu_read_unlock();
801 : 3 : }
802 : :
803 : : #else /* CONFIG_CGROUPS */
804 : :
805 : : static inline void cgroup_account_cputime(struct task_struct *task,
806 : : u64 delta_exec) {}
807 : : static inline void cgroup_account_cputime_field(struct task_struct *task,
808 : : enum cpu_usage_stat index,
809 : : u64 delta_exec) {}
810 : :
811 : : #endif /* CONFIG_CGROUPS */
812 : :
813 : : /*
814 : : * sock->sk_cgrp_data handling. For more info, see sock_cgroup_data
815 : : * definition in cgroup-defs.h.
816 : : */
817 : : #ifdef CONFIG_SOCK_CGROUP_DATA
818 : :
819 : : #if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID)
820 : : extern spinlock_t cgroup_sk_update_lock;
821 : : #endif
822 : :
823 : : void cgroup_sk_alloc_disable(void);
824 : : void cgroup_sk_alloc(struct sock_cgroup_data *skcd);
825 : : void cgroup_sk_clone(struct sock_cgroup_data *skcd);
826 : : void cgroup_sk_free(struct sock_cgroup_data *skcd);
827 : :
828 : 0 : static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd)
829 : : {
830 : : #if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID)
831 : : unsigned long v;
832 : :
833 : : /*
834 : : * @skcd->val is 64bit but the following is safe on 32bit too as we
835 : : * just need the lower ulong to be written and read atomically.
836 : : */
837 : 3 : v = READ_ONCE(skcd->val);
838 : :
839 : 3 : if (v & 3)
840 : : return &cgrp_dfl_root.cgrp;
841 : :
842 : 3 : return (struct cgroup *)(unsigned long)v ?: &cgrp_dfl_root.cgrp;
843 : : #else
844 : : return (struct cgroup *)(unsigned long)skcd->val;
845 : : #endif
846 : : }
847 : :
848 : : #else /* CONFIG_CGROUP_DATA */
849 : :
850 : : static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {}
851 : : static inline void cgroup_sk_clone(struct sock_cgroup_data *skcd) {}
852 : : static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {}
853 : :
854 : : #endif /* CONFIG_CGROUP_DATA */
855 : :
856 : : struct cgroup_namespace {
857 : : refcount_t count;
858 : : struct ns_common ns;
859 : : struct user_namespace *user_ns;
860 : : struct ucounts *ucounts;
861 : : struct css_set *root_cset;
862 : : };
863 : :
864 : : extern struct cgroup_namespace init_cgroup_ns;
865 : :
866 : : #ifdef CONFIG_CGROUPS
867 : :
868 : : void free_cgroup_ns(struct cgroup_namespace *ns);
869 : :
870 : : struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,
871 : : struct user_namespace *user_ns,
872 : : struct cgroup_namespace *old_ns);
873 : :
874 : : int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
875 : : struct cgroup_namespace *ns);
876 : :
877 : : #else /* !CONFIG_CGROUPS */
878 : :
879 : : static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
880 : : static inline struct cgroup_namespace *
881 : : copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
882 : : struct cgroup_namespace *old_ns)
883 : : {
884 : : return old_ns;
885 : : }
886 : :
887 : : #endif /* !CONFIG_CGROUPS */
888 : :
889 : : static inline void get_cgroup_ns(struct cgroup_namespace *ns)
890 : : {
891 : 3 : if (ns)
892 : 3 : refcount_inc(&ns->count);
893 : : }
894 : :
895 : 3 : static inline void put_cgroup_ns(struct cgroup_namespace *ns)
896 : : {
897 : 3 : if (ns && refcount_dec_and_test(&ns->count))
898 : 0 : free_cgroup_ns(ns);
899 : 3 : }
900 : :
901 : : #ifdef CONFIG_CGROUPS
902 : :
903 : : void cgroup_enter_frozen(void);
904 : : void cgroup_leave_frozen(bool always_leave);
905 : : void cgroup_update_frozen(struct cgroup *cgrp);
906 : : void cgroup_freeze(struct cgroup *cgrp, bool freeze);
907 : : void cgroup_freezer_migrate_task(struct task_struct *task, struct cgroup *src,
908 : : struct cgroup *dst);
909 : :
910 : 3 : static inline bool cgroup_task_freeze(struct task_struct *task)
911 : : {
912 : : bool ret;
913 : :
914 : 3 : if (task->flags & PF_KTHREAD)
915 : : return false;
916 : :
917 : : rcu_read_lock();
918 : 3 : ret = test_bit(CGRP_FREEZE, &task_dfl_cgroup(task)->flags);
919 : : rcu_read_unlock();
920 : :
921 : 3 : return ret;
922 : : }
923 : :
924 : : static inline bool cgroup_task_frozen(struct task_struct *task)
925 : : {
926 : 3 : return task->frozen;
927 : : }
928 : :
929 : : #else /* !CONFIG_CGROUPS */
930 : :
931 : : static inline void cgroup_enter_frozen(void) { }
932 : : static inline void cgroup_leave_frozen(bool always_leave) { }
933 : : static inline bool cgroup_task_freeze(struct task_struct *task)
934 : : {
935 : : return false;
936 : : }
937 : : static inline bool cgroup_task_frozen(struct task_struct *task)
938 : : {
939 : : return false;
940 : : }
941 : :
942 : : #endif /* !CONFIG_CGROUPS */
943 : :
944 : : #ifdef CONFIG_CGROUP_BPF
945 : : static inline void cgroup_bpf_get(struct cgroup *cgrp)
946 : : {
947 : 3 : percpu_ref_get(&cgrp->bpf.refcnt);
948 : : }
949 : :
950 : : static inline void cgroup_bpf_put(struct cgroup *cgrp)
951 : : {
952 : 3 : percpu_ref_put(&cgrp->bpf.refcnt);
953 : : }
954 : :
955 : : #else /* CONFIG_CGROUP_BPF */
956 : :
957 : : static inline void cgroup_bpf_get(struct cgroup *cgrp) {}
958 : : static inline void cgroup_bpf_put(struct cgroup *cgrp) {}
959 : :
960 : : #endif /* CONFIG_CGROUP_BPF */
961 : :
962 : : #endif /* _LINUX_CGROUP_H */
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