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