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