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ddbcc7e8 PM |
1 | #ifndef _LINUX_CGROUP_H |
2 | #define _LINUX_CGROUP_H | |
3 | /* | |
4 | * cgroup interface | |
5 | * | |
6 | * Copyright (C) 2003 BULL SA | |
7 | * Copyright (C) 2004-2006 Silicon Graphics, Inc. | |
8 | * | |
9 | */ | |
10 | ||
11 | #include <linux/sched.h> | |
ddbcc7e8 PM |
12 | #include <linux/cpumask.h> |
13 | #include <linux/nodemask.h> | |
eb6fd504 | 14 | #include <linux/rculist.h> |
846c7bb0 | 15 | #include <linux/cgroupstats.h> |
25a7e684 | 16 | #include <linux/fs.h> |
7da11279 | 17 | #include <linux/seq_file.h> |
2bd59d48 | 18 | #include <linux/kernfs.h> |
49d1dc4b | 19 | #include <linux/jump_label.h> |
a79a908f AK |
20 | #include <linux/types.h> |
21 | #include <linux/ns_common.h> | |
22 | #include <linux/nsproxy.h> | |
23 | #include <linux/user_namespace.h> | |
387ad967 | 24 | #include <linux/refcount.h> |
ddbcc7e8 | 25 | |
b4a04ab7 | 26 | #include <linux/cgroup-defs.h> |
ddbcc7e8 PM |
27 | |
28 | #ifdef CONFIG_CGROUPS | |
29 | ||
6abc8ca1 TH |
30 | /* |
31 | * All weight knobs on the default hierarhcy should use the following min, | |
32 | * default and max values. The default value is the logarithmic center of | |
33 | * MIN and MAX and allows 100x to be expressed in both directions. | |
34 | */ | |
35 | #define CGROUP_WEIGHT_MIN 1 | |
36 | #define CGROUP_WEIGHT_DFL 100 | |
37 | #define CGROUP_WEIGHT_MAX 10000 | |
38 | ||
bc2fb7ed TH |
39 | /* walk only threadgroup leaders */ |
40 | #define CSS_TASK_ITER_PROCS (1U << 0) | |
450ee0c1 TH |
41 | /* walk all threaded css_sets in the domain */ |
42 | #define CSS_TASK_ITER_THREADED (1U << 1) | |
bc2fb7ed | 43 | |
c326aa2b TH |
44 | /* a css_task_iter should be treated as an opaque object */ |
45 | struct css_task_iter { | |
46 | struct cgroup_subsys *ss; | |
bc2fb7ed | 47 | unsigned int flags; |
c326aa2b TH |
48 | |
49 | struct list_head *cset_pos; | |
50 | struct list_head *cset_head; | |
ddbcc7e8 | 51 | |
450ee0c1 TH |
52 | struct list_head *tcset_pos; |
53 | struct list_head *tcset_head; | |
54 | ||
c326aa2b TH |
55 | struct list_head *task_pos; |
56 | struct list_head *tasks_head; | |
57 | struct list_head *mg_tasks_head; | |
ed27b9f7 TH |
58 | |
59 | struct css_set *cur_cset; | |
450ee0c1 | 60 | struct css_set *cur_dcset; |
ed27b9f7 TH |
61 | struct task_struct *cur_task; |
62 | struct list_head iters_node; /* css_set->task_iters */ | |
c326aa2b | 63 | }; |
ddbcc7e8 | 64 | |
c326aa2b TH |
65 | extern struct cgroup_root cgrp_dfl_root; |
66 | extern struct css_set init_css_set; | |
a424316c | 67 | |
c326aa2b | 68 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys; |
817929ec | 69 | #include <linux/cgroup_subsys.h> |
817929ec PM |
70 | #undef SUBSYS |
71 | ||
49d1dc4b TH |
72 | #define SUBSYS(_x) \ |
73 | extern struct static_key_true _x ## _cgrp_subsys_enabled_key; \ | |
74 | extern struct static_key_true _x ## _cgrp_subsys_on_dfl_key; | |
75 | #include <linux/cgroup_subsys.h> | |
76 | #undef SUBSYS | |
77 | ||
78 | /** | |
79 | * cgroup_subsys_enabled - fast test on whether a subsys is enabled | |
80 | * @ss: subsystem in question | |
81 | */ | |
82 | #define cgroup_subsys_enabled(ss) \ | |
83 | static_branch_likely(&ss ## _enabled_key) | |
84 | ||
85 | /** | |
86 | * cgroup_subsys_on_dfl - fast test on whether a subsys is on default hierarchy | |
87 | * @ss: subsystem in question | |
88 | */ | |
89 | #define cgroup_subsys_on_dfl(ss) \ | |
90 | static_branch_likely(&ss ## _on_dfl_key) | |
91 | ||
c326aa2b TH |
92 | bool css_has_online_children(struct cgroup_subsys_state *css); |
93 | struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss); | |
94 | struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgroup, | |
95 | struct cgroup_subsys *ss); | |
96 | struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry, | |
97 | struct cgroup_subsys *ss); | |
98 | ||
16af4396 | 99 | struct cgroup *cgroup_get_from_path(const char *path); |
1f3fe7eb | 100 | struct cgroup *cgroup_get_from_fd(int fd); |
16af4396 | 101 | |
c326aa2b TH |
102 | int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); |
103 | int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from); | |
104 | ||
105 | int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); | |
106 | int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); | |
107 | int cgroup_rm_cftypes(struct cftype *cfts); | |
34c06254 | 108 | void cgroup_file_notify(struct cgroup_file *cfile); |
c326aa2b | 109 | |
4c737b41 | 110 | int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen); |
c326aa2b TH |
111 | int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry); |
112 | int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, | |
113 | struct pid *pid, struct task_struct *tsk); | |
114 | ||
115 | void cgroup_fork(struct task_struct *p); | |
b53202e6 ON |
116 | extern int cgroup_can_fork(struct task_struct *p); |
117 | extern void cgroup_cancel_fork(struct task_struct *p); | |
118 | extern void cgroup_post_fork(struct task_struct *p); | |
c326aa2b | 119 | void cgroup_exit(struct task_struct *p); |
2e91fa7f | 120 | void cgroup_free(struct task_struct *p); |
c326aa2b TH |
121 | |
122 | int cgroup_init_early(void); | |
123 | int cgroup_init(void); | |
124 | ||
5c9d535b | 125 | /* |
c326aa2b TH |
126 | * Iteration helpers and macros. |
127 | */ | |
128 | ||
129 | struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos, | |
130 | struct cgroup_subsys_state *parent); | |
131 | struct cgroup_subsys_state *css_next_descendant_pre(struct cgroup_subsys_state *pos, | |
132 | struct cgroup_subsys_state *css); | |
133 | struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state *pos); | |
134 | struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos, | |
135 | struct cgroup_subsys_state *css); | |
136 | ||
1f7dd3e5 TH |
137 | struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset, |
138 | struct cgroup_subsys_state **dst_cssp); | |
139 | struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset, | |
140 | struct cgroup_subsys_state **dst_cssp); | |
c326aa2b | 141 | |
bc2fb7ed | 142 | void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags, |
c326aa2b TH |
143 | struct css_task_iter *it); |
144 | struct task_struct *css_task_iter_next(struct css_task_iter *it); | |
145 | void css_task_iter_end(struct css_task_iter *it); | |
146 | ||
147 | /** | |
148 | * css_for_each_child - iterate through children of a css | |
149 | * @pos: the css * to use as the loop cursor | |
150 | * @parent: css whose children to walk | |
151 | * | |
152 | * Walk @parent's children. Must be called under rcu_read_lock(). | |
153 | * | |
154 | * If a subsystem synchronizes ->css_online() and the start of iteration, a | |
155 | * css which finished ->css_online() is guaranteed to be visible in the | |
156 | * future iterations and will stay visible until the last reference is put. | |
157 | * A css which hasn't finished ->css_online() or already finished | |
158 | * ->css_offline() may show up during traversal. It's each subsystem's | |
159 | * responsibility to synchronize against on/offlining. | |
5c9d535b | 160 | * |
c326aa2b TH |
161 | * It is allowed to temporarily drop RCU read lock during iteration. The |
162 | * caller is responsible for ensuring that @pos remains accessible until | |
163 | * the start of the next iteration by, for example, bumping the css refcnt. | |
5c9d535b | 164 | */ |
c326aa2b TH |
165 | #define css_for_each_child(pos, parent) \ |
166 | for ((pos) = css_next_child(NULL, (parent)); (pos); \ | |
167 | (pos) = css_next_child((pos), (parent))) | |
ddbcc7e8 | 168 | |
c326aa2b TH |
169 | /** |
170 | * css_for_each_descendant_pre - pre-order walk of a css's descendants | |
171 | * @pos: the css * to use as the loop cursor | |
172 | * @root: css whose descendants to walk | |
173 | * | |
174 | * Walk @root's descendants. @root is included in the iteration and the | |
175 | * first node to be visited. Must be called under rcu_read_lock(). | |
176 | * | |
177 | * If a subsystem synchronizes ->css_online() and the start of iteration, a | |
178 | * css which finished ->css_online() is guaranteed to be visible in the | |
179 | * future iterations and will stay visible until the last reference is put. | |
180 | * A css which hasn't finished ->css_online() or already finished | |
181 | * ->css_offline() may show up during traversal. It's each subsystem's | |
182 | * responsibility to synchronize against on/offlining. | |
183 | * | |
184 | * For example, the following guarantees that a descendant can't escape | |
185 | * state updates of its ancestors. | |
186 | * | |
187 | * my_online(@css) | |
188 | * { | |
189 | * Lock @css's parent and @css; | |
190 | * Inherit state from the parent; | |
191 | * Unlock both. | |
192 | * } | |
193 | * | |
194 | * my_update_state(@css) | |
195 | * { | |
196 | * css_for_each_descendant_pre(@pos, @css) { | |
197 | * Lock @pos; | |
198 | * if (@pos == @css) | |
199 | * Update @css's state; | |
200 | * else | |
201 | * Verify @pos is alive and inherit state from its parent; | |
202 | * Unlock @pos; | |
203 | * } | |
204 | * } | |
205 | * | |
206 | * As long as the inheriting step, including checking the parent state, is | |
207 | * enclosed inside @pos locking, double-locking the parent isn't necessary | |
208 | * while inheriting. The state update to the parent is guaranteed to be | |
209 | * visible by walking order and, as long as inheriting operations to the | |
210 | * same @pos are atomic to each other, multiple updates racing each other | |
211 | * still result in the correct state. It's guaranateed that at least one | |
212 | * inheritance happens for any css after the latest update to its parent. | |
213 | * | |
214 | * If checking parent's state requires locking the parent, each inheriting | |
215 | * iteration should lock and unlock both @pos->parent and @pos. | |
216 | * | |
217 | * Alternatively, a subsystem may choose to use a single global lock to | |
218 | * synchronize ->css_online() and ->css_offline() against tree-walking | |
219 | * operations. | |
220 | * | |
221 | * It is allowed to temporarily drop RCU read lock during iteration. The | |
222 | * caller is responsible for ensuring that @pos remains accessible until | |
223 | * the start of the next iteration by, for example, bumping the css refcnt. | |
224 | */ | |
225 | #define css_for_each_descendant_pre(pos, css) \ | |
226 | for ((pos) = css_next_descendant_pre(NULL, (css)); (pos); \ | |
227 | (pos) = css_next_descendant_pre((pos), (css))) | |
228 | ||
229 | /** | |
230 | * css_for_each_descendant_post - post-order walk of a css's descendants | |
231 | * @pos: the css * to use as the loop cursor | |
232 | * @css: css whose descendants to walk | |
233 | * | |
234 | * Similar to css_for_each_descendant_pre() but performs post-order | |
235 | * traversal instead. @root is included in the iteration and the last | |
236 | * node to be visited. | |
237 | * | |
238 | * If a subsystem synchronizes ->css_online() and the start of iteration, a | |
239 | * css which finished ->css_online() is guaranteed to be visible in the | |
240 | * future iterations and will stay visible until the last reference is put. | |
241 | * A css which hasn't finished ->css_online() or already finished | |
242 | * ->css_offline() may show up during traversal. It's each subsystem's | |
243 | * responsibility to synchronize against on/offlining. | |
244 | * | |
245 | * Note that the walk visibility guarantee example described in pre-order | |
246 | * walk doesn't apply the same to post-order walks. | |
247 | */ | |
248 | #define css_for_each_descendant_post(pos, css) \ | |
249 | for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \ | |
250 | (pos) = css_next_descendant_post((pos), (css))) | |
251 | ||
252 | /** | |
253 | * cgroup_taskset_for_each - iterate cgroup_taskset | |
254 | * @task: the loop cursor | |
1f7dd3e5 | 255 | * @dst_css: the destination css |
c326aa2b | 256 | * @tset: taskset to iterate |
4530eddb TH |
257 | * |
258 | * @tset may contain multiple tasks and they may belong to multiple | |
1f7dd3e5 TH |
259 | * processes. |
260 | * | |
261 | * On the v2 hierarchy, there may be tasks from multiple processes and they | |
262 | * may not share the source or destination csses. | |
263 | * | |
264 | * On traditional hierarchies, when there are multiple tasks in @tset, if a | |
265 | * task of a process is in @tset, all tasks of the process are in @tset. | |
266 | * Also, all are guaranteed to share the same source and destination csses. | |
4530eddb TH |
267 | * |
268 | * Iteration is not in any specific order. | |
c326aa2b | 269 | */ |
1f7dd3e5 TH |
270 | #define cgroup_taskset_for_each(task, dst_css, tset) \ |
271 | for ((task) = cgroup_taskset_first((tset), &(dst_css)); \ | |
272 | (task); \ | |
273 | (task) = cgroup_taskset_next((tset), &(dst_css))) | |
ddbcc7e8 | 274 | |
4530eddb TH |
275 | /** |
276 | * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset | |
277 | * @leader: the loop cursor | |
1f7dd3e5 | 278 | * @dst_css: the destination css |
7b4632f0 | 279 | * @tset: taskset to iterate |
4530eddb TH |
280 | * |
281 | * Iterate threadgroup leaders of @tset. For single-task migrations, @tset | |
282 | * may not contain any. | |
283 | */ | |
1f7dd3e5 TH |
284 | #define cgroup_taskset_for_each_leader(leader, dst_css, tset) \ |
285 | for ((leader) = cgroup_taskset_first((tset), &(dst_css)); \ | |
286 | (leader); \ | |
287 | (leader) = cgroup_taskset_next((tset), &(dst_css))) \ | |
4530eddb TH |
288 | if ((leader) != (leader)->group_leader) \ |
289 | ; \ | |
290 | else | |
291 | ||
c326aa2b TH |
292 | /* |
293 | * Inline functions. | |
294 | */ | |
ddbcc7e8 | 295 | |
5de0107e TH |
296 | /** |
297 | * css_get - obtain a reference on the specified css | |
298 | * @css: target css | |
299 | * | |
300 | * The caller must already have a reference. | |
ddbcc7e8 | 301 | */ |
ddbcc7e8 PM |
302 | static inline void css_get(struct cgroup_subsys_state *css) |
303 | { | |
3b514d24 TH |
304 | if (!(css->flags & CSS_NO_REF)) |
305 | percpu_ref_get(&css->refcnt); | |
ddbcc7e8 | 306 | } |
e7c5ec91 | 307 | |
e8ea14cc JW |
308 | /** |
309 | * css_get_many - obtain references on the specified css | |
310 | * @css: target css | |
311 | * @n: number of references to get | |
312 | * | |
313 | * The caller must already have a reference. | |
314 | */ | |
315 | static inline void css_get_many(struct cgroup_subsys_state *css, unsigned int n) | |
316 | { | |
317 | if (!(css->flags & CSS_NO_REF)) | |
318 | percpu_ref_get_many(&css->refcnt, n); | |
319 | } | |
320 | ||
6f4524d3 TH |
321 | /** |
322 | * css_tryget - try to obtain a reference on the specified css | |
323 | * @css: target css | |
324 | * | |
325 | * Obtain a reference on @css unless it already has reached zero and is | |
326 | * being released. This function doesn't care whether @css is on or | |
327 | * offline. The caller naturally needs to ensure that @css is accessible | |
328 | * but doesn't have to be holding a reference on it - IOW, RCU protected | |
329 | * access is good enough for this function. Returns %true if a reference | |
330 | * count was successfully obtained; %false otherwise. | |
331 | */ | |
332 | static inline bool css_tryget(struct cgroup_subsys_state *css) | |
333 | { | |
334 | if (!(css->flags & CSS_NO_REF)) | |
335 | return percpu_ref_tryget(&css->refcnt); | |
336 | return true; | |
337 | } | |
338 | ||
5de0107e | 339 | /** |
ec903c0c | 340 | * css_tryget_online - try to obtain a reference on the specified css if online |
5de0107e TH |
341 | * @css: target css |
342 | * | |
ec903c0c TH |
343 | * Obtain a reference on @css if it's online. The caller naturally needs |
344 | * to ensure that @css is accessible but doesn't have to be holding a | |
5de0107e TH |
345 | * reference on it - IOW, RCU protected access is good enough for this |
346 | * function. Returns %true if a reference count was successfully obtained; | |
347 | * %false otherwise. | |
348 | */ | |
ec903c0c | 349 | static inline bool css_tryget_online(struct cgroup_subsys_state *css) |
e7c5ec91 | 350 | { |
3b514d24 TH |
351 | if (!(css->flags & CSS_NO_REF)) |
352 | return percpu_ref_tryget_live(&css->refcnt); | |
353 | return true; | |
e7c5ec91 | 354 | } |
2f7ee569 | 355 | |
41c25707 TH |
356 | /** |
357 | * css_is_dying - test whether the specified css is dying | |
358 | * @css: target css | |
359 | * | |
360 | * Test whether @css is in the process of offlining or already offline. In | |
361 | * most cases, ->css_online() and ->css_offline() callbacks should be | |
362 | * enough; however, the actual offline operations are RCU delayed and this | |
363 | * test returns %true also when @css is scheduled to be offlined. | |
364 | * | |
365 | * This is useful, for example, when the use case requires synchronous | |
366 | * behavior with respect to cgroup removal. cgroup removal schedules css | |
367 | * offlining but the css can seem alive while the operation is being | |
368 | * delayed. If the delay affects user visible semantics, this test can be | |
369 | * used to resolve the situation. | |
370 | */ | |
371 | static inline bool css_is_dying(struct cgroup_subsys_state *css) | |
372 | { | |
373 | return !(css->flags & CSS_NO_REF) && percpu_ref_is_dying(&css->refcnt); | |
374 | } | |
375 | ||
2f7ee569 | 376 | /** |
5de0107e TH |
377 | * css_put - put a css reference |
378 | * @css: target css | |
379 | * | |
ec903c0c | 380 | * Put a reference obtained via css_get() and css_tryget_online(). |
2f7ee569 | 381 | */ |
ddbcc7e8 PM |
382 | static inline void css_put(struct cgroup_subsys_state *css) |
383 | { | |
3b514d24 TH |
384 | if (!(css->flags & CSS_NO_REF)) |
385 | percpu_ref_put(&css->refcnt); | |
ddbcc7e8 | 386 | } |
2f7ee569 | 387 | |
e8ea14cc JW |
388 | /** |
389 | * css_put_many - put css references | |
390 | * @css: target css | |
391 | * @n: number of references to put | |
392 | * | |
393 | * Put references obtained via css_get() and css_tryget_online(). | |
21acb9ca | 394 | */ |
e8ea14cc JW |
395 | static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n) |
396 | { | |
397 | if (!(css->flags & CSS_NO_REF)) | |
398 | percpu_ref_put_many(&css->refcnt, n); | |
399 | } | |
ddbcc7e8 | 400 | |
3e48930c TH |
401 | static inline void cgroup_get(struct cgroup *cgrp) |
402 | { | |
403 | css_get(&cgrp->self); | |
404 | } | |
405 | ||
406 | static inline bool cgroup_tryget(struct cgroup *cgrp) | |
407 | { | |
408 | return css_tryget(&cgrp->self); | |
409 | } | |
410 | ||
16af4396 TH |
411 | static inline void cgroup_put(struct cgroup *cgrp) |
412 | { | |
413 | css_put(&cgrp->self); | |
414 | } | |
415 | ||
14611e51 TH |
416 | /** |
417 | * task_css_set_check - obtain a task's css_set with extra access conditions | |
418 | * @task: the task to obtain css_set for | |
419 | * @__c: extra condition expression to be passed to rcu_dereference_check() | |
420 | * | |
421 | * A task's css_set is RCU protected, initialized and exited while holding | |
422 | * task_lock(), and can only be modified while holding both cgroup_mutex | |
423 | * and task_lock() while the task is alive. This macro verifies that the | |
424 | * caller is inside proper critical section and returns @task's css_set. | |
425 | * | |
426 | * The caller can also specify additional allowed conditions via @__c, such | |
427 | * as locks used during the cgroup_subsys::attach() methods. | |
dc61b1d6 | 428 | */ |
2219449a TH |
429 | #ifdef CONFIG_PROVE_RCU |
430 | extern struct mutex cgroup_mutex; | |
f0d9a5f1 | 431 | extern spinlock_t css_set_lock; |
14611e51 TH |
432 | #define task_css_set_check(task, __c) \ |
433 | rcu_dereference_check((task)->cgroups, \ | |
0e1d768f | 434 | lockdep_is_held(&cgroup_mutex) || \ |
f0d9a5f1 | 435 | lockdep_is_held(&css_set_lock) || \ |
0e1d768f | 436 | ((task)->flags & PF_EXITING) || (__c)) |
2219449a | 437 | #else |
14611e51 TH |
438 | #define task_css_set_check(task, __c) \ |
439 | rcu_dereference((task)->cgroups) | |
2219449a | 440 | #endif |
dc61b1d6 | 441 | |
14611e51 | 442 | /** |
8af01f56 | 443 | * task_css_check - obtain css for (task, subsys) w/ extra access conds |
14611e51 TH |
444 | * @task: the target task |
445 | * @subsys_id: the target subsystem ID | |
446 | * @__c: extra condition expression to be passed to rcu_dereference_check() | |
447 | * | |
448 | * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The | |
449 | * synchronization rules are the same as task_css_set_check(). | |
450 | */ | |
8af01f56 | 451 | #define task_css_check(task, subsys_id, __c) \ |
14611e51 TH |
452 | task_css_set_check((task), (__c))->subsys[(subsys_id)] |
453 | ||
454 | /** | |
455 | * task_css_set - obtain a task's css_set | |
456 | * @task: the task to obtain css_set for | |
457 | * | |
458 | * See task_css_set_check(). | |
459 | */ | |
460 | static inline struct css_set *task_css_set(struct task_struct *task) | |
461 | { | |
462 | return task_css_set_check(task, false); | |
463 | } | |
464 | ||
465 | /** | |
8af01f56 | 466 | * task_css - obtain css for (task, subsys) |
14611e51 TH |
467 | * @task: the target task |
468 | * @subsys_id: the target subsystem ID | |
469 | * | |
8af01f56 | 470 | * See task_css_check(). |
14611e51 | 471 | */ |
8af01f56 TH |
472 | static inline struct cgroup_subsys_state *task_css(struct task_struct *task, |
473 | int subsys_id) | |
ddbcc7e8 | 474 | { |
8af01f56 | 475 | return task_css_check(task, subsys_id, false); |
ddbcc7e8 PM |
476 | } |
477 | ||
ec438699 TH |
478 | /** |
479 | * task_get_css - find and get the css for (task, subsys) | |
480 | * @task: the target task | |
481 | * @subsys_id: the target subsystem ID | |
482 | * | |
483 | * Find the css for the (@task, @subsys_id) combination, increment a | |
484 | * reference on and return it. This function is guaranteed to return a | |
485 | * valid css. | |
486 | */ | |
487 | static inline struct cgroup_subsys_state * | |
488 | task_get_css(struct task_struct *task, int subsys_id) | |
489 | { | |
490 | struct cgroup_subsys_state *css; | |
491 | ||
492 | rcu_read_lock(); | |
493 | while (true) { | |
494 | css = task_css(task, subsys_id); | |
495 | if (likely(css_tryget_online(css))) | |
496 | break; | |
497 | cpu_relax(); | |
498 | } | |
499 | rcu_read_unlock(); | |
500 | return css; | |
501 | } | |
502 | ||
5024ae29 TH |
503 | /** |
504 | * task_css_is_root - test whether a task belongs to the root css | |
505 | * @task: the target task | |
506 | * @subsys_id: the target subsystem ID | |
507 | * | |
508 | * Test whether @task belongs to the root css on the specified subsystem. | |
509 | * May be invoked in any context. | |
510 | */ | |
511 | static inline bool task_css_is_root(struct task_struct *task, int subsys_id) | |
512 | { | |
513 | return task_css_check(task, subsys_id, true) == | |
514 | init_css_set.subsys[subsys_id]; | |
515 | } | |
516 | ||
8af01f56 TH |
517 | static inline struct cgroup *task_cgroup(struct task_struct *task, |
518 | int subsys_id) | |
ddbcc7e8 | 519 | { |
8af01f56 | 520 | return task_css(task, subsys_id)->cgroup; |
ddbcc7e8 PM |
521 | } |
522 | ||
3e48930c TH |
523 | static inline struct cgroup *task_dfl_cgroup(struct task_struct *task) |
524 | { | |
525 | return task_css_set(task)->dfl_cgrp; | |
526 | } | |
527 | ||
528 | static inline struct cgroup *cgroup_parent(struct cgroup *cgrp) | |
529 | { | |
530 | struct cgroup_subsys_state *parent_css = cgrp->self.parent; | |
531 | ||
532 | if (parent_css) | |
533 | return container_of(parent_css, struct cgroup, self); | |
534 | return NULL; | |
535 | } | |
536 | ||
b11cfb58 TH |
537 | /** |
538 | * cgroup_is_descendant - test ancestry | |
539 | * @cgrp: the cgroup to be tested | |
540 | * @ancestor: possible ancestor of @cgrp | |
541 | * | |
542 | * Test whether @cgrp is a descendant of @ancestor. It also returns %true | |
543 | * if @cgrp == @ancestor. This function is safe to call as long as @cgrp | |
544 | * and @ancestor are accessible. | |
545 | */ | |
546 | static inline bool cgroup_is_descendant(struct cgroup *cgrp, | |
547 | struct cgroup *ancestor) | |
548 | { | |
549 | if (cgrp->root != ancestor->root || cgrp->level < ancestor->level) | |
550 | return false; | |
551 | return cgrp->ancestor_ids[ancestor->level] == ancestor->id; | |
552 | } | |
553 | ||
aed704b7 SD |
554 | /** |
555 | * task_under_cgroup_hierarchy - test task's membership of cgroup ancestry | |
556 | * @task: the task to be tested | |
557 | * @ancestor: possible ancestor of @task's cgroup | |
558 | * | |
559 | * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor. | |
560 | * It follows all the same rules as cgroup_is_descendant, and only applies | |
561 | * to the default hierarchy. | |
562 | */ | |
563 | static inline bool task_under_cgroup_hierarchy(struct task_struct *task, | |
564 | struct cgroup *ancestor) | |
565 | { | |
566 | struct css_set *cset = task_css_set(task); | |
567 | ||
568 | return cgroup_is_descendant(cset->dfl_cgrp, ancestor); | |
569 | } | |
570 | ||
07bc356e | 571 | /* no synchronization, the result can only be used as a hint */ |
27bd4dbb | 572 | static inline bool cgroup_is_populated(struct cgroup *cgrp) |
07bc356e | 573 | { |
454000ad TH |
574 | return cgrp->nr_populated_csets + cgrp->nr_populated_domain_children + |
575 | cgrp->nr_populated_threaded_children; | |
07bc356e | 576 | } |
f3d46500 | 577 | |
f29374b1 | 578 | /* returns ino associated with a cgroup */ |
b1664924 TH |
579 | static inline ino_t cgroup_ino(struct cgroup *cgrp) |
580 | { | |
c53cd490 | 581 | return cgrp->kn->id.ino; |
b1664924 | 582 | } |
3ebb2b6e | 583 | |
b4168640 TH |
584 | /* cft/css accessors for cftype->write() operation */ |
585 | static inline struct cftype *of_cft(struct kernfs_open_file *of) | |
7da11279 | 586 | { |
2bd59d48 | 587 | return of->kn->priv; |
7da11279 | 588 | } |
0f0a2b4f | 589 | |
b4168640 | 590 | struct cgroup_subsys_state *of_css(struct kernfs_open_file *of); |
817929ec | 591 | |
b4168640 TH |
592 | /* cft/css accessors for cftype->seq_*() operations */ |
593 | static inline struct cftype *seq_cft(struct seq_file *seq) | |
594 | { | |
595 | return of_cft(seq->private); | |
596 | } | |
e535837b | 597 | |
b4168640 TH |
598 | static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq) |
599 | { | |
600 | return of_css(seq->private); | |
601 | } | |
31583bb0 | 602 | |
e61734c5 TH |
603 | /* |
604 | * Name / path handling functions. All are thin wrappers around the kernfs | |
605 | * counterparts and can be called under any context. | |
606 | */ | |
38460b48 | 607 | |
e61734c5 TH |
608 | static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen) |
609 | { | |
fdce6bf8 | 610 | return kernfs_name(cgrp->kn, buf, buflen); |
e61734c5 | 611 | } |
ddbcc7e8 | 612 | |
4c737b41 | 613 | static inline int cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen) |
e61734c5 | 614 | { |
fdce6bf8 | 615 | return kernfs_path(cgrp->kn, buf, buflen); |
e61734c5 | 616 | } |
f3ba5380 | 617 | |
e61734c5 TH |
618 | static inline void pr_cont_cgroup_name(struct cgroup *cgrp) |
619 | { | |
fdce6bf8 | 620 | pr_cont_kernfs_name(cgrp->kn); |
e61734c5 | 621 | } |
ddbcc7e8 | 622 | |
e61734c5 | 623 | static inline void pr_cont_cgroup_path(struct cgroup *cgrp) |
846c7bb0 | 624 | { |
fdce6bf8 | 625 | pr_cont_kernfs_path(cgrp->kn); |
846c7bb0 | 626 | } |
ddbcc7e8 | 627 | |
77f88796 TH |
628 | static inline void cgroup_init_kthreadd(void) |
629 | { | |
630 | /* | |
631 | * kthreadd is inherited by all kthreads, keep it in the root so | |
632 | * that the new kthreads are guaranteed to stay in the root until | |
633 | * initialization is finished. | |
634 | */ | |
635 | current->no_cgroup_migration = 1; | |
636 | } | |
637 | ||
638 | static inline void cgroup_kthread_ready(void) | |
639 | { | |
640 | /* | |
641 | * This kthread finished initialization. The creator should have | |
642 | * set PF_NO_SETAFFINITY if this kthread should stay in the root. | |
643 | */ | |
644 | current->no_cgroup_migration = 0; | |
645 | } | |
646 | ||
121508df SL |
647 | static inline union kernfs_node_id *cgroup_get_kernfs_id(struct cgroup *cgrp) |
648 | { | |
649 | return &cgrp->kn->id; | |
650 | } | |
69fd5c39 SL |
651 | |
652 | void cgroup_path_from_kernfs_id(const union kernfs_node_id *id, | |
653 | char *buf, size_t buflen); | |
ddbcc7e8 PM |
654 | #else /* !CONFIG_CGROUPS */ |
655 | ||
f3ba5380 | 656 | struct cgroup_subsys_state; |
aed704b7 | 657 | struct cgroup; |
f3ba5380 | 658 | |
c326aa2b | 659 | static inline void css_put(struct cgroup_subsys_state *css) {} |
31583bb0 | 660 | static inline int cgroup_attach_task_all(struct task_struct *from, |
c326aa2b TH |
661 | struct task_struct *t) { return 0; } |
662 | static inline int cgroupstats_build(struct cgroupstats *stats, | |
663 | struct dentry *dentry) { return -EINVAL; } | |
664 | ||
b4f48b63 | 665 | static inline void cgroup_fork(struct task_struct *p) {} |
b53202e6 ON |
666 | static inline int cgroup_can_fork(struct task_struct *p) { return 0; } |
667 | static inline void cgroup_cancel_fork(struct task_struct *p) {} | |
668 | static inline void cgroup_post_fork(struct task_struct *p) {} | |
1ec41830 | 669 | static inline void cgroup_exit(struct task_struct *p) {} |
2e91fa7f | 670 | static inline void cgroup_free(struct task_struct *p) {} |
ddbcc7e8 | 671 | |
c326aa2b TH |
672 | static inline int cgroup_init_early(void) { return 0; } |
673 | static inline int cgroup_init(void) { return 0; } | |
77f88796 TH |
674 | static inline void cgroup_init_kthreadd(void) {} |
675 | static inline void cgroup_kthread_ready(void) {} | |
121508df SL |
676 | static inline union kernfs_node_id *cgroup_get_kernfs_id(struct cgroup *cgrp) |
677 | { | |
678 | return NULL; | |
679 | } | |
d7926ee3 | 680 | |
aed704b7 SD |
681 | static inline bool task_under_cgroup_hierarchy(struct task_struct *task, |
682 | struct cgroup *ancestor) | |
683 | { | |
684 | return true; | |
685 | } | |
69fd5c39 SL |
686 | |
687 | static inline void cgroup_path_from_kernfs_id(const union kernfs_node_id *id, | |
688 | char *buf, size_t buflen) {} | |
ddbcc7e8 PM |
689 | #endif /* !CONFIG_CGROUPS */ |
690 | ||
bd1060a1 TH |
691 | /* |
692 | * sock->sk_cgrp_data handling. For more info, see sock_cgroup_data | |
693 | * definition in cgroup-defs.h. | |
694 | */ | |
695 | #ifdef CONFIG_SOCK_CGROUP_DATA | |
696 | ||
697 | #if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID) | |
698 | extern spinlock_t cgroup_sk_update_lock; | |
699 | #endif | |
700 | ||
701 | void cgroup_sk_alloc_disable(void); | |
702 | void cgroup_sk_alloc(struct sock_cgroup_data *skcd); | |
703 | void cgroup_sk_free(struct sock_cgroup_data *skcd); | |
704 | ||
705 | static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd) | |
706 | { | |
707 | #if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID) | |
708 | unsigned long v; | |
709 | ||
710 | /* | |
711 | * @skcd->val is 64bit but the following is safe on 32bit too as we | |
712 | * just need the lower ulong to be written and read atomically. | |
713 | */ | |
714 | v = READ_ONCE(skcd->val); | |
715 | ||
716 | if (v & 1) | |
717 | return &cgrp_dfl_root.cgrp; | |
718 | ||
719 | return (struct cgroup *)(unsigned long)v ?: &cgrp_dfl_root.cgrp; | |
720 | #else | |
721 | return (struct cgroup *)(unsigned long)skcd->val; | |
722 | #endif | |
723 | } | |
724 | ||
725 | #else /* CONFIG_CGROUP_DATA */ | |
726 | ||
727 | static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {} | |
728 | static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {} | |
729 | ||
730 | #endif /* CONFIG_CGROUP_DATA */ | |
731 | ||
a79a908f | 732 | struct cgroup_namespace { |
387ad967 | 733 | refcount_t count; |
a79a908f AK |
734 | struct ns_common ns; |
735 | struct user_namespace *user_ns; | |
d08311dd | 736 | struct ucounts *ucounts; |
a79a908f AK |
737 | struct css_set *root_cset; |
738 | }; | |
739 | ||
740 | extern struct cgroup_namespace init_cgroup_ns; | |
741 | ||
742 | #ifdef CONFIG_CGROUPS | |
743 | ||
744 | void free_cgroup_ns(struct cgroup_namespace *ns); | |
745 | ||
746 | struct cgroup_namespace *copy_cgroup_ns(unsigned long flags, | |
747 | struct user_namespace *user_ns, | |
748 | struct cgroup_namespace *old_ns); | |
749 | ||
4c737b41 TH |
750 | int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen, |
751 | struct cgroup_namespace *ns); | |
a79a908f AK |
752 | |
753 | #else /* !CONFIG_CGROUPS */ | |
754 | ||
755 | static inline void free_cgroup_ns(struct cgroup_namespace *ns) { } | |
756 | static inline struct cgroup_namespace * | |
757 | copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns, | |
758 | struct cgroup_namespace *old_ns) | |
759 | { | |
760 | return old_ns; | |
761 | } | |
762 | ||
763 | #endif /* !CONFIG_CGROUPS */ | |
764 | ||
765 | static inline void get_cgroup_ns(struct cgroup_namespace *ns) | |
766 | { | |
767 | if (ns) | |
387ad967 | 768 | refcount_inc(&ns->count); |
a79a908f AK |
769 | } |
770 | ||
771 | static inline void put_cgroup_ns(struct cgroup_namespace *ns) | |
772 | { | |
387ad967 | 773 | if (ns && refcount_dec_and_test(&ns->count)) |
a79a908f AK |
774 | free_cgroup_ns(ns); |
775 | } | |
776 | ||
ddbcc7e8 | 777 | #endif /* _LINUX_CGROUP_H */ |