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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> |
ddbcc7e8 | 20 | |
b4a04ab7 | 21 | #include <linux/cgroup-defs.h> |
ddbcc7e8 PM |
22 | |
23 | #ifdef CONFIG_CGROUPS | |
24 | ||
6abc8ca1 TH |
25 | /* |
26 | * All weight knobs on the default hierarhcy should use the following min, | |
27 | * default and max values. The default value is the logarithmic center of | |
28 | * MIN and MAX and allows 100x to be expressed in both directions. | |
29 | */ | |
30 | #define CGROUP_WEIGHT_MIN 1 | |
31 | #define CGROUP_WEIGHT_DFL 100 | |
32 | #define CGROUP_WEIGHT_MAX 10000 | |
33 | ||
c326aa2b TH |
34 | /* a css_task_iter should be treated as an opaque object */ |
35 | struct css_task_iter { | |
36 | struct cgroup_subsys *ss; | |
37 | ||
38 | struct list_head *cset_pos; | |
39 | struct list_head *cset_head; | |
ddbcc7e8 | 40 | |
c326aa2b TH |
41 | struct list_head *task_pos; |
42 | struct list_head *tasks_head; | |
43 | struct list_head *mg_tasks_head; | |
ed27b9f7 TH |
44 | |
45 | struct css_set *cur_cset; | |
46 | struct task_struct *cur_task; | |
47 | struct list_head iters_node; /* css_set->task_iters */ | |
c326aa2b | 48 | }; |
ddbcc7e8 | 49 | |
c326aa2b TH |
50 | extern struct cgroup_root cgrp_dfl_root; |
51 | extern struct css_set init_css_set; | |
a424316c | 52 | |
c326aa2b | 53 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys; |
817929ec | 54 | #include <linux/cgroup_subsys.h> |
817929ec PM |
55 | #undef SUBSYS |
56 | ||
49d1dc4b TH |
57 | #define SUBSYS(_x) \ |
58 | extern struct static_key_true _x ## _cgrp_subsys_enabled_key; \ | |
59 | extern struct static_key_true _x ## _cgrp_subsys_on_dfl_key; | |
60 | #include <linux/cgroup_subsys.h> | |
61 | #undef SUBSYS | |
62 | ||
63 | /** | |
64 | * cgroup_subsys_enabled - fast test on whether a subsys is enabled | |
65 | * @ss: subsystem in question | |
66 | */ | |
67 | #define cgroup_subsys_enabled(ss) \ | |
68 | static_branch_likely(&ss ## _enabled_key) | |
69 | ||
70 | /** | |
71 | * cgroup_subsys_on_dfl - fast test on whether a subsys is on default hierarchy | |
72 | * @ss: subsystem in question | |
73 | */ | |
74 | #define cgroup_subsys_on_dfl(ss) \ | |
75 | static_branch_likely(&ss ## _on_dfl_key) | |
76 | ||
c326aa2b TH |
77 | bool css_has_online_children(struct cgroup_subsys_state *css); |
78 | struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss); | |
79 | struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgroup, | |
80 | struct cgroup_subsys *ss); | |
81 | struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry, | |
82 | struct cgroup_subsys *ss); | |
83 | ||
84 | bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor); | |
85 | int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); | |
86 | int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from); | |
87 | ||
88 | int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); | |
89 | int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); | |
90 | int cgroup_rm_cftypes(struct cftype *cfts); | |
91 | ||
92 | char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen); | |
93 | int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry); | |
94 | int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, | |
95 | struct pid *pid, struct task_struct *tsk); | |
96 | ||
97 | void cgroup_fork(struct task_struct *p); | |
7e47682e AS |
98 | extern int cgroup_can_fork(struct task_struct *p, |
99 | void *ss_priv[CGROUP_CANFORK_COUNT]); | |
100 | extern void cgroup_cancel_fork(struct task_struct *p, | |
101 | void *ss_priv[CGROUP_CANFORK_COUNT]); | |
102 | extern void cgroup_post_fork(struct task_struct *p, | |
103 | void *old_ss_priv[CGROUP_CANFORK_COUNT]); | |
c326aa2b | 104 | void cgroup_exit(struct task_struct *p); |
2e91fa7f | 105 | void cgroup_free(struct task_struct *p); |
c326aa2b TH |
106 | |
107 | int cgroup_init_early(void); | |
108 | int cgroup_init(void); | |
109 | ||
5c9d535b | 110 | /* |
c326aa2b TH |
111 | * Iteration helpers and macros. |
112 | */ | |
113 | ||
114 | struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos, | |
115 | struct cgroup_subsys_state *parent); | |
116 | struct cgroup_subsys_state *css_next_descendant_pre(struct cgroup_subsys_state *pos, | |
117 | struct cgroup_subsys_state *css); | |
118 | struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state *pos); | |
119 | struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos, | |
120 | struct cgroup_subsys_state *css); | |
121 | ||
122 | struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset); | |
123 | struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset); | |
124 | ||
125 | void css_task_iter_start(struct cgroup_subsys_state *css, | |
126 | struct css_task_iter *it); | |
127 | struct task_struct *css_task_iter_next(struct css_task_iter *it); | |
128 | void css_task_iter_end(struct css_task_iter *it); | |
129 | ||
130 | /** | |
131 | * css_for_each_child - iterate through children of a css | |
132 | * @pos: the css * to use as the loop cursor | |
133 | * @parent: css whose children to walk | |
134 | * | |
135 | * Walk @parent's children. Must be called under rcu_read_lock(). | |
136 | * | |
137 | * If a subsystem synchronizes ->css_online() and the start of iteration, a | |
138 | * css which finished ->css_online() is guaranteed to be visible in the | |
139 | * future iterations and will stay visible until the last reference is put. | |
140 | * A css which hasn't finished ->css_online() or already finished | |
141 | * ->css_offline() may show up during traversal. It's each subsystem's | |
142 | * responsibility to synchronize against on/offlining. | |
5c9d535b | 143 | * |
c326aa2b TH |
144 | * It is allowed to temporarily drop RCU read lock during iteration. The |
145 | * caller is responsible for ensuring that @pos remains accessible until | |
146 | * the start of the next iteration by, for example, bumping the css refcnt. | |
5c9d535b | 147 | */ |
c326aa2b TH |
148 | #define css_for_each_child(pos, parent) \ |
149 | for ((pos) = css_next_child(NULL, (parent)); (pos); \ | |
150 | (pos) = css_next_child((pos), (parent))) | |
ddbcc7e8 | 151 | |
c326aa2b TH |
152 | /** |
153 | * css_for_each_descendant_pre - pre-order walk of a css's descendants | |
154 | * @pos: the css * to use as the loop cursor | |
155 | * @root: css whose descendants to walk | |
156 | * | |
157 | * Walk @root's descendants. @root is included in the iteration and the | |
158 | * first node to be visited. Must be called under rcu_read_lock(). | |
159 | * | |
160 | * If a subsystem synchronizes ->css_online() and the start of iteration, a | |
161 | * css which finished ->css_online() is guaranteed to be visible in the | |
162 | * future iterations and will stay visible until the last reference is put. | |
163 | * A css which hasn't finished ->css_online() or already finished | |
164 | * ->css_offline() may show up during traversal. It's each subsystem's | |
165 | * responsibility to synchronize against on/offlining. | |
166 | * | |
167 | * For example, the following guarantees that a descendant can't escape | |
168 | * state updates of its ancestors. | |
169 | * | |
170 | * my_online(@css) | |
171 | * { | |
172 | * Lock @css's parent and @css; | |
173 | * Inherit state from the parent; | |
174 | * Unlock both. | |
175 | * } | |
176 | * | |
177 | * my_update_state(@css) | |
178 | * { | |
179 | * css_for_each_descendant_pre(@pos, @css) { | |
180 | * Lock @pos; | |
181 | * if (@pos == @css) | |
182 | * Update @css's state; | |
183 | * else | |
184 | * Verify @pos is alive and inherit state from its parent; | |
185 | * Unlock @pos; | |
186 | * } | |
187 | * } | |
188 | * | |
189 | * As long as the inheriting step, including checking the parent state, is | |
190 | * enclosed inside @pos locking, double-locking the parent isn't necessary | |
191 | * while inheriting. The state update to the parent is guaranteed to be | |
192 | * visible by walking order and, as long as inheriting operations to the | |
193 | * same @pos are atomic to each other, multiple updates racing each other | |
194 | * still result in the correct state. It's guaranateed that at least one | |
195 | * inheritance happens for any css after the latest update to its parent. | |
196 | * | |
197 | * If checking parent's state requires locking the parent, each inheriting | |
198 | * iteration should lock and unlock both @pos->parent and @pos. | |
199 | * | |
200 | * Alternatively, a subsystem may choose to use a single global lock to | |
201 | * synchronize ->css_online() and ->css_offline() against tree-walking | |
202 | * operations. | |
203 | * | |
204 | * It is allowed to temporarily drop RCU read lock during iteration. The | |
205 | * caller is responsible for ensuring that @pos remains accessible until | |
206 | * the start of the next iteration by, for example, bumping the css refcnt. | |
207 | */ | |
208 | #define css_for_each_descendant_pre(pos, css) \ | |
209 | for ((pos) = css_next_descendant_pre(NULL, (css)); (pos); \ | |
210 | (pos) = css_next_descendant_pre((pos), (css))) | |
211 | ||
212 | /** | |
213 | * css_for_each_descendant_post - post-order walk of a css's descendants | |
214 | * @pos: the css * to use as the loop cursor | |
215 | * @css: css whose descendants to walk | |
216 | * | |
217 | * Similar to css_for_each_descendant_pre() but performs post-order | |
218 | * traversal instead. @root is included in the iteration and the last | |
219 | * node to be visited. | |
220 | * | |
221 | * If a subsystem synchronizes ->css_online() and the start of iteration, a | |
222 | * css which finished ->css_online() is guaranteed to be visible in the | |
223 | * future iterations and will stay visible until the last reference is put. | |
224 | * A css which hasn't finished ->css_online() or already finished | |
225 | * ->css_offline() may show up during traversal. It's each subsystem's | |
226 | * responsibility to synchronize against on/offlining. | |
227 | * | |
228 | * Note that the walk visibility guarantee example described in pre-order | |
229 | * walk doesn't apply the same to post-order walks. | |
230 | */ | |
231 | #define css_for_each_descendant_post(pos, css) \ | |
232 | for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \ | |
233 | (pos) = css_next_descendant_post((pos), (css))) | |
234 | ||
235 | /** | |
236 | * cgroup_taskset_for_each - iterate cgroup_taskset | |
237 | * @task: the loop cursor | |
238 | * @tset: taskset to iterate | |
4530eddb TH |
239 | * |
240 | * @tset may contain multiple tasks and they may belong to multiple | |
241 | * processes. When there are multiple tasks in @tset, if a task of a | |
242 | * process is in @tset, all tasks of the process are in @tset. Also, all | |
243 | * are guaranteed to share the same source and destination csses. | |
244 | * | |
245 | * Iteration is not in any specific order. | |
c326aa2b TH |
246 | */ |
247 | #define cgroup_taskset_for_each(task, tset) \ | |
248 | for ((task) = cgroup_taskset_first((tset)); (task); \ | |
249 | (task) = cgroup_taskset_next((tset))) | |
ddbcc7e8 | 250 | |
4530eddb TH |
251 | /** |
252 | * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset | |
253 | * @leader: the loop cursor | |
254 | * @tset: takset to iterate | |
255 | * | |
256 | * Iterate threadgroup leaders of @tset. For single-task migrations, @tset | |
257 | * may not contain any. | |
258 | */ | |
259 | #define cgroup_taskset_for_each_leader(leader, tset) \ | |
260 | for ((leader) = cgroup_taskset_first((tset)); (leader); \ | |
261 | (leader) = cgroup_taskset_next((tset))) \ | |
262 | if ((leader) != (leader)->group_leader) \ | |
263 | ; \ | |
264 | else | |
265 | ||
c326aa2b TH |
266 | /* |
267 | * Inline functions. | |
268 | */ | |
ddbcc7e8 | 269 | |
5de0107e TH |
270 | /** |
271 | * css_get - obtain a reference on the specified css | |
272 | * @css: target css | |
273 | * | |
274 | * The caller must already have a reference. | |
ddbcc7e8 | 275 | */ |
ddbcc7e8 PM |
276 | static inline void css_get(struct cgroup_subsys_state *css) |
277 | { | |
3b514d24 TH |
278 | if (!(css->flags & CSS_NO_REF)) |
279 | percpu_ref_get(&css->refcnt); | |
ddbcc7e8 | 280 | } |
e7c5ec91 | 281 | |
e8ea14cc JW |
282 | /** |
283 | * css_get_many - obtain references on the specified css | |
284 | * @css: target css | |
285 | * @n: number of references to get | |
286 | * | |
287 | * The caller must already have a reference. | |
288 | */ | |
289 | static inline void css_get_many(struct cgroup_subsys_state *css, unsigned int n) | |
290 | { | |
291 | if (!(css->flags & CSS_NO_REF)) | |
292 | percpu_ref_get_many(&css->refcnt, n); | |
293 | } | |
294 | ||
6f4524d3 TH |
295 | /** |
296 | * css_tryget - try to obtain a reference on the specified css | |
297 | * @css: target css | |
298 | * | |
299 | * Obtain a reference on @css unless it already has reached zero and is | |
300 | * being released. This function doesn't care whether @css is on or | |
301 | * offline. The caller naturally needs to ensure that @css is accessible | |
302 | * but doesn't have to be holding a reference on it - IOW, RCU protected | |
303 | * access is good enough for this function. Returns %true if a reference | |
304 | * count was successfully obtained; %false otherwise. | |
305 | */ | |
306 | static inline bool css_tryget(struct cgroup_subsys_state *css) | |
307 | { | |
308 | if (!(css->flags & CSS_NO_REF)) | |
309 | return percpu_ref_tryget(&css->refcnt); | |
310 | return true; | |
311 | } | |
312 | ||
5de0107e | 313 | /** |
ec903c0c | 314 | * css_tryget_online - try to obtain a reference on the specified css if online |
5de0107e TH |
315 | * @css: target css |
316 | * | |
ec903c0c TH |
317 | * Obtain a reference on @css if it's online. The caller naturally needs |
318 | * to ensure that @css is accessible but doesn't have to be holding a | |
5de0107e TH |
319 | * reference on it - IOW, RCU protected access is good enough for this |
320 | * function. Returns %true if a reference count was successfully obtained; | |
321 | * %false otherwise. | |
322 | */ | |
ec903c0c | 323 | static inline bool css_tryget_online(struct cgroup_subsys_state *css) |
e7c5ec91 | 324 | { |
3b514d24 TH |
325 | if (!(css->flags & CSS_NO_REF)) |
326 | return percpu_ref_tryget_live(&css->refcnt); | |
327 | return true; | |
e7c5ec91 | 328 | } |
2f7ee569 TH |
329 | |
330 | /** | |
5de0107e TH |
331 | * css_put - put a css reference |
332 | * @css: target css | |
333 | * | |
ec903c0c | 334 | * Put a reference obtained via css_get() and css_tryget_online(). |
2f7ee569 | 335 | */ |
ddbcc7e8 PM |
336 | static inline void css_put(struct cgroup_subsys_state *css) |
337 | { | |
3b514d24 TH |
338 | if (!(css->flags & CSS_NO_REF)) |
339 | percpu_ref_put(&css->refcnt); | |
ddbcc7e8 | 340 | } |
2f7ee569 | 341 | |
e8ea14cc JW |
342 | /** |
343 | * css_put_many - put css references | |
344 | * @css: target css | |
345 | * @n: number of references to put | |
346 | * | |
347 | * Put references obtained via css_get() and css_tryget_online(). | |
21acb9ca | 348 | */ |
e8ea14cc JW |
349 | static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n) |
350 | { | |
351 | if (!(css->flags & CSS_NO_REF)) | |
352 | percpu_ref_put_many(&css->refcnt, n); | |
353 | } | |
ddbcc7e8 | 354 | |
14611e51 TH |
355 | /** |
356 | * task_css_set_check - obtain a task's css_set with extra access conditions | |
357 | * @task: the task to obtain css_set for | |
358 | * @__c: extra condition expression to be passed to rcu_dereference_check() | |
359 | * | |
360 | * A task's css_set is RCU protected, initialized and exited while holding | |
361 | * task_lock(), and can only be modified while holding both cgroup_mutex | |
362 | * and task_lock() while the task is alive. This macro verifies that the | |
363 | * caller is inside proper critical section and returns @task's css_set. | |
364 | * | |
365 | * The caller can also specify additional allowed conditions via @__c, such | |
366 | * as locks used during the cgroup_subsys::attach() methods. | |
dc61b1d6 | 367 | */ |
2219449a TH |
368 | #ifdef CONFIG_PROVE_RCU |
369 | extern struct mutex cgroup_mutex; | |
f0d9a5f1 | 370 | extern spinlock_t css_set_lock; |
14611e51 TH |
371 | #define task_css_set_check(task, __c) \ |
372 | rcu_dereference_check((task)->cgroups, \ | |
0e1d768f | 373 | lockdep_is_held(&cgroup_mutex) || \ |
f0d9a5f1 | 374 | lockdep_is_held(&css_set_lock) || \ |
0e1d768f | 375 | ((task)->flags & PF_EXITING) || (__c)) |
2219449a | 376 | #else |
14611e51 TH |
377 | #define task_css_set_check(task, __c) \ |
378 | rcu_dereference((task)->cgroups) | |
2219449a | 379 | #endif |
dc61b1d6 | 380 | |
14611e51 | 381 | /** |
8af01f56 | 382 | * task_css_check - obtain css for (task, subsys) w/ extra access conds |
14611e51 TH |
383 | * @task: the target task |
384 | * @subsys_id: the target subsystem ID | |
385 | * @__c: extra condition expression to be passed to rcu_dereference_check() | |
386 | * | |
387 | * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The | |
388 | * synchronization rules are the same as task_css_set_check(). | |
389 | */ | |
8af01f56 | 390 | #define task_css_check(task, subsys_id, __c) \ |
14611e51 TH |
391 | task_css_set_check((task), (__c))->subsys[(subsys_id)] |
392 | ||
393 | /** | |
394 | * task_css_set - obtain a task's css_set | |
395 | * @task: the task to obtain css_set for | |
396 | * | |
397 | * See task_css_set_check(). | |
398 | */ | |
399 | static inline struct css_set *task_css_set(struct task_struct *task) | |
400 | { | |
401 | return task_css_set_check(task, false); | |
402 | } | |
403 | ||
404 | /** | |
8af01f56 | 405 | * task_css - obtain css for (task, subsys) |
14611e51 TH |
406 | * @task: the target task |
407 | * @subsys_id: the target subsystem ID | |
408 | * | |
8af01f56 | 409 | * See task_css_check(). |
14611e51 | 410 | */ |
8af01f56 TH |
411 | static inline struct cgroup_subsys_state *task_css(struct task_struct *task, |
412 | int subsys_id) | |
ddbcc7e8 | 413 | { |
8af01f56 | 414 | return task_css_check(task, subsys_id, false); |
ddbcc7e8 PM |
415 | } |
416 | ||
ec438699 TH |
417 | /** |
418 | * task_get_css - find and get the css for (task, subsys) | |
419 | * @task: the target task | |
420 | * @subsys_id: the target subsystem ID | |
421 | * | |
422 | * Find the css for the (@task, @subsys_id) combination, increment a | |
423 | * reference on and return it. This function is guaranteed to return a | |
424 | * valid css. | |
425 | */ | |
426 | static inline struct cgroup_subsys_state * | |
427 | task_get_css(struct task_struct *task, int subsys_id) | |
428 | { | |
429 | struct cgroup_subsys_state *css; | |
430 | ||
431 | rcu_read_lock(); | |
432 | while (true) { | |
433 | css = task_css(task, subsys_id); | |
434 | if (likely(css_tryget_online(css))) | |
435 | break; | |
436 | cpu_relax(); | |
437 | } | |
438 | rcu_read_unlock(); | |
439 | return css; | |
440 | } | |
441 | ||
5024ae29 TH |
442 | /** |
443 | * task_css_is_root - test whether a task belongs to the root css | |
444 | * @task: the target task | |
445 | * @subsys_id: the target subsystem ID | |
446 | * | |
447 | * Test whether @task belongs to the root css on the specified subsystem. | |
448 | * May be invoked in any context. | |
449 | */ | |
450 | static inline bool task_css_is_root(struct task_struct *task, int subsys_id) | |
451 | { | |
452 | return task_css_check(task, subsys_id, true) == | |
453 | init_css_set.subsys[subsys_id]; | |
454 | } | |
455 | ||
8af01f56 TH |
456 | static inline struct cgroup *task_cgroup(struct task_struct *task, |
457 | int subsys_id) | |
ddbcc7e8 | 458 | { |
8af01f56 | 459 | return task_css(task, subsys_id)->cgroup; |
ddbcc7e8 PM |
460 | } |
461 | ||
07bc356e | 462 | /* no synchronization, the result can only be used as a hint */ |
27bd4dbb | 463 | static inline bool cgroup_is_populated(struct cgroup *cgrp) |
07bc356e | 464 | { |
27bd4dbb | 465 | return cgrp->populated_cnt; |
07bc356e | 466 | } |
f3d46500 | 467 | |
f29374b1 | 468 | /* returns ino associated with a cgroup */ |
b1664924 TH |
469 | static inline ino_t cgroup_ino(struct cgroup *cgrp) |
470 | { | |
f29374b1 | 471 | return cgrp->kn->ino; |
b1664924 | 472 | } |
3ebb2b6e | 473 | |
b4168640 TH |
474 | /* cft/css accessors for cftype->write() operation */ |
475 | static inline struct cftype *of_cft(struct kernfs_open_file *of) | |
7da11279 | 476 | { |
2bd59d48 | 477 | return of->kn->priv; |
7da11279 | 478 | } |
0f0a2b4f | 479 | |
b4168640 | 480 | struct cgroup_subsys_state *of_css(struct kernfs_open_file *of); |
817929ec | 481 | |
b4168640 TH |
482 | /* cft/css accessors for cftype->seq_*() operations */ |
483 | static inline struct cftype *seq_cft(struct seq_file *seq) | |
484 | { | |
485 | return of_cft(seq->private); | |
486 | } | |
e535837b | 487 | |
b4168640 TH |
488 | static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq) |
489 | { | |
490 | return of_css(seq->private); | |
491 | } | |
31583bb0 | 492 | |
e61734c5 TH |
493 | /* |
494 | * Name / path handling functions. All are thin wrappers around the kernfs | |
495 | * counterparts and can be called under any context. | |
496 | */ | |
38460b48 | 497 | |
e61734c5 TH |
498 | static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen) |
499 | { | |
fdce6bf8 | 500 | return kernfs_name(cgrp->kn, buf, buflen); |
e61734c5 | 501 | } |
ddbcc7e8 | 502 | |
e61734c5 TH |
503 | static inline char * __must_check cgroup_path(struct cgroup *cgrp, char *buf, |
504 | size_t buflen) | |
505 | { | |
fdce6bf8 | 506 | return kernfs_path(cgrp->kn, buf, buflen); |
e61734c5 | 507 | } |
f3ba5380 | 508 | |
e61734c5 TH |
509 | static inline void pr_cont_cgroup_name(struct cgroup *cgrp) |
510 | { | |
fdce6bf8 | 511 | pr_cont_kernfs_name(cgrp->kn); |
e61734c5 | 512 | } |
ddbcc7e8 | 513 | |
e61734c5 | 514 | static inline void pr_cont_cgroup_path(struct cgroup *cgrp) |
846c7bb0 | 515 | { |
fdce6bf8 | 516 | pr_cont_kernfs_path(cgrp->kn); |
846c7bb0 | 517 | } |
ddbcc7e8 | 518 | |
6f60eade TH |
519 | /** |
520 | * cgroup_file_notify - generate a file modified event for a cgroup_file | |
521 | * @cfile: target cgroup_file | |
522 | * | |
523 | * @cfile must have been obtained by setting cftype->file_offset. | |
524 | */ | |
525 | static inline void cgroup_file_notify(struct cgroup_file *cfile) | |
526 | { | |
527 | /* might not have been created due to one of the CFTYPE selector flags */ | |
528 | if (cfile->kn) | |
529 | kernfs_notify(cfile->kn); | |
530 | } | |
531 | ||
ddbcc7e8 PM |
532 | #else /* !CONFIG_CGROUPS */ |
533 | ||
f3ba5380 | 534 | struct cgroup_subsys_state; |
f3ba5380 | 535 | |
c326aa2b | 536 | static inline void css_put(struct cgroup_subsys_state *css) {} |
31583bb0 | 537 | static inline int cgroup_attach_task_all(struct task_struct *from, |
c326aa2b TH |
538 | struct task_struct *t) { return 0; } |
539 | static inline int cgroupstats_build(struct cgroupstats *stats, | |
540 | struct dentry *dentry) { return -EINVAL; } | |
541 | ||
b4f48b63 | 542 | static inline void cgroup_fork(struct task_struct *p) {} |
7e47682e AS |
543 | static inline int cgroup_can_fork(struct task_struct *p, |
544 | void *ss_priv[CGROUP_CANFORK_COUNT]) | |
545 | { return 0; } | |
546 | static inline void cgroup_cancel_fork(struct task_struct *p, | |
547 | void *ss_priv[CGROUP_CANFORK_COUNT]) {} | |
548 | static inline void cgroup_post_fork(struct task_struct *p, | |
549 | void *ss_priv[CGROUP_CANFORK_COUNT]) {} | |
1ec41830 | 550 | static inline void cgroup_exit(struct task_struct *p) {} |
2e91fa7f | 551 | static inline void cgroup_free(struct task_struct *p) {} |
ddbcc7e8 | 552 | |
c326aa2b TH |
553 | static inline int cgroup_init_early(void) { return 0; } |
554 | static inline int cgroup_init(void) { return 0; } | |
d7926ee3 | 555 | |
ddbcc7e8 PM |
556 | #endif /* !CONFIG_CGROUPS */ |
557 | ||
558 | #endif /* _LINUX_CGROUP_H */ |