include/linux/cgroup.h

   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>
  12 #include <linux/cpumask.h>
  13 #include <linux/nodemask.h>
  14 #include <linux/rculist.h>
  15 #include <linux/cgroupstats.h>
  16 #include <linux/fs.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/kernfs.h>
  19 #include <linux/jump_label.h>
  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>
  25
  26 #include <linux/cgroup-defs.h>
  27
  28 #ifdef CONFIG_CGROUPS
  29
  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
  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;
  45
  46         struct list_head                *task_pos;
  47         struct list_head                *tasks_head;
  48         struct list_head                *mg_tasks_head;
  49
  50         struct css_set                  *cur_cset;
  51         struct task_struct              *cur_task;
  52         struct list_head                iters_node;     /* css_set->task_iters */
  53 };
  54
  55 extern struct cgroup_root cgrp_dfl_root;
  56 extern struct css_set init_css_set;
  57
  58 #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys;
  59 #include <linux/cgroup_subsys.h>
  60 #undef SUBSYS
  61
  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
  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
  89 struct cgroup *cgroup_get_from_path(const char *path);
  90 struct cgroup *cgroup_get_from_fd(int fd);
  91
  92 int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);
  93 int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
  94
  95 int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
  96 int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
  97 int cgroup_rm_cftypes(struct cftype *cfts);
  98 void cgroup_file_notify(struct cgroup_file *cfile);
  99
 100 int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);
 101 int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry);
 102 int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
 103                      struct pid *pid, struct task_struct *tsk);
 104
 105 void cgroup_fork(struct task_struct *p);
 106 extern int cgroup_can_fork(struct task_struct *p);
 107 extern void cgroup_cancel_fork(struct task_struct *p);
 108 extern void cgroup_post_fork(struct task_struct *p);
 109 void cgroup_exit(struct task_struct *p);
 110 void cgroup_free(struct task_struct *p);
 111
 112 int cgroup_init_early(void);
 113 int cgroup_init(void);
 114
 115 /*
 116  * Iteration helpers and macros.
 117  */
 118
 119 struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos,
 120                                            struct cgroup_subsys_state *parent);
 121 struct cgroup_subsys_state *css_next_descendant_pre(struct cgroup_subsys_state *pos,
 122                                                     struct cgroup_subsys_state *css);
 123 struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state *pos);
 124 struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos,
 125                                                      struct cgroup_subsys_state *css);
 126
 127 struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset,
 128                                          struct cgroup_subsys_state **dst_cssp);
 129 struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset,
 130                                         struct cgroup_subsys_state **dst_cssp);
 131
 132 void css_task_iter_start(struct cgroup_subsys_state *css,
 133                          struct css_task_iter *it);
 134 struct task_struct *css_task_iter_next(struct css_task_iter *it);
 135 void css_task_iter_end(struct css_task_iter *it);
 136
 137 /**
 138  * css_for_each_child - iterate through children of a css
 139  * @pos: the css * to use as the loop cursor
 140  * @parent: css whose children to walk
 141  *
 142  * Walk @parent's children.  Must be called under rcu_read_lock().
 143  *
 144  * If a subsystem synchronizes ->css_online() and the start of iteration, a
 145  * css which finished ->css_online() is guaranteed to be visible in the
 146  * future iterations and will stay visible until the last reference is put.
 147  * A css which hasn't finished ->css_online() or already finished
 148  * ->css_offline() may show up during traversal.  It's each subsystem's
 149  * responsibility to synchronize against on/offlining.
 150  *
 151  * It is allowed to temporarily drop RCU read lock during iteration.  The
 152  * caller is responsible for ensuring that @pos remains accessible until
 153  * the start of the next iteration by, for example, bumping the css refcnt.
 154  */
 155 #define css_for_each_child(pos, parent)                                 \
 156         for ((pos) = css_next_child(NULL, (parent)); (pos);             \
 157              (pos) = css_next_child((pos), (parent)))
 158
 159 /**
 160  * css_for_each_descendant_pre - pre-order walk of a css's descendants
 161  * @pos: the css * to use as the loop cursor
 162  * @root: css whose descendants to walk
 163  *
 164  * Walk @root's descendants.  @root is included in the iteration and the
 165  * first node to be visited.  Must be called under rcu_read_lock().
 166  *
 167  * If a subsystem synchronizes ->css_online() and the start of iteration, a
 168  * css which finished ->css_online() is guaranteed to be visible in the
 169  * future iterations and will stay visible until the last reference is put.
 170  * A css which hasn't finished ->css_online() or already finished
 171  * ->css_offline() may show up during traversal.  It's each subsystem's
 172  * responsibility to synchronize against on/offlining.
 173  *
 174  * For example, the following guarantees that a descendant can't escape
 175  * state updates of its ancestors.
 176  *
 177  * my_online(@css)
 178  * {
 179  *      Lock @css's parent and @css;
 180  *      Inherit state from the parent;
 181  *      Unlock both.
 182  * }
 183  *
 184  * my_update_state(@css)
 185  * {
 186  *      css_for_each_descendant_pre(@pos, @css) {
 187  *              Lock @pos;
 188  *              if (@pos == @css)
 189  *                      Update @css's state;
 190  *              else
 191  *                      Verify @pos is alive and inherit state from its parent;
 192  *              Unlock @pos;
 193  *      }
 194  * }
 195  *
 196  * As long as the inheriting step, including checking the parent state, is
 197  * enclosed inside @pos locking, double-locking the parent isn't necessary
 198  * while inheriting.  The state update to the parent is guaranteed to be
 199  * visible by walking order and, as long as inheriting operations to the
 200  * same @pos are atomic to each other, multiple updates racing each other
 201  * still result in the correct state.  It's guaranateed that at least one
 202  * inheritance happens for any css after the latest update to its parent.
 203  *
 204  * If checking parent's state requires locking the parent, each inheriting
 205  * iteration should lock and unlock both @pos->parent and @pos.
 206  *
 207  * Alternatively, a subsystem may choose to use a single global lock to
 208  * synchronize ->css_online() and ->css_offline() against tree-walking
 209  * operations.
 210  *
 211  * It is allowed to temporarily drop RCU read lock during iteration.  The
 212  * caller is responsible for ensuring that @pos remains accessible until
 213  * the start of the next iteration by, for example, bumping the css refcnt.
 214  */
 215 #define css_for_each_descendant_pre(pos, css)                           \
 216         for ((pos) = css_next_descendant_pre(NULL, (css)); (pos);       \
 217              (pos) = css_next_descendant_pre((pos), (css)))
 218
 219 /**
 220  * css_for_each_descendant_post - post-order walk of a css's descendants
 221  * @pos: the css * to use as the loop cursor
 222  * @css: css whose descendants to walk
 223  *
 224  * Similar to css_for_each_descendant_pre() but performs post-order
 225  * traversal instead.  @root is included in the iteration and the last
 226  * node to be visited.
 227  *
 228  * If a subsystem synchronizes ->css_online() and the start of iteration, a
 229  * css which finished ->css_online() is guaranteed to be visible in the
 230  * future iterations and will stay visible until the last reference is put.
 231  * A css which hasn't finished ->css_online() or already finished
 232  * ->css_offline() may show up during traversal.  It's each subsystem's
 233  * responsibility to synchronize against on/offlining.
 234  *
 235  * Note that the walk visibility guarantee example described in pre-order
 236  * walk doesn't apply the same to post-order walks.
 237  */
 238 #define css_for_each_descendant_post(pos, css)                          \
 239         for ((pos) = css_next_descendant_post(NULL, (css)); (pos);      \
 240              (pos) = css_next_descendant_post((pos), (css)))
 241
 242 /**
 243  * cgroup_taskset_for_each - iterate cgroup_taskset
 244  * @task: the loop cursor
 245  * @dst_css: the destination css
 246  * @tset: taskset to iterate
 247  *
 248  * @tset may contain multiple tasks and they may belong to multiple
 249  * processes.
 250  *
 251  * On the v2 hierarchy, there may be tasks from multiple processes and they
 252  * may not share the source or destination csses.
 253  *
 254  * On traditional hierarchies, when there are multiple tasks in @tset, if a
 255  * task of a process is in @tset, all tasks of the process are in @tset.
 256  * Also, all are guaranteed to share the same source and destination csses.
 257  *
 258  * Iteration is not in any specific order.
 259  */
 260 #define cgroup_taskset_for_each(task, dst_css, tset)                    \
 261         for ((task) = cgroup_taskset_first((tset), &(dst_css));         \
 262              (task);                                                    \
 263              (task) = cgroup_taskset_next((tset), &(dst_css)))
 264
 265 /**
 266  * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset
 267  * @leader: the loop cursor
 268  * @dst_css: the destination css
 269  * @tset: takset to iterate
 270  *
 271  * Iterate threadgroup leaders of @tset.  For single-task migrations, @tset
 272  * may not contain any.
 273  */
 274 #define cgroup_taskset_for_each_leader(leader, dst_css, tset)           \
 275         for ((leader) = cgroup_taskset_first((tset), &(dst_css));       \
 276              (leader);                                                  \
 277              (leader) = cgroup_taskset_next((tset), &(dst_css)))        \
 278                 if ((leader) != (leader)->group_leader)                 \
 279                         ;                                               \
 280                 else
 281
 282 /*
 283  * Inline functions.
 284  */
 285
 286 /**
 287  * css_get - obtain a reference on the specified css
 288  * @css: target css
 289  *
 290  * The caller must already have a reference.
 291  */
 292 static inline void css_get(struct cgroup_subsys_state *css)
 293 {
 294         if (!(css->flags & CSS_NO_REF))
 295                 percpu_ref_get(&css->refcnt);
 296 }
 297
 298 /**
 299  * css_get_many - obtain references on the specified css
 300  * @css: target css
 301  * @n: number of references to get
 302  *
 303  * The caller must already have a reference.
 304  */
 305 static inline void css_get_many(struct cgroup_subsys_state *css, unsigned int n)
 306 {
 307         if (!(css->flags & CSS_NO_REF))
 308                 percpu_ref_get_many(&css->refcnt, n);
 309 }
 310
 311 /**
 312  * css_tryget - try to obtain a reference on the specified css
 313  * @css: target css
 314  *
 315  * Obtain a reference on @css unless it already has reached zero and is
 316  * being released.  This function doesn't care whether @css is on or
 317  * offline.  The caller naturally needs to ensure that @css is accessible
 318  * but doesn't have to be holding a reference on it - IOW, RCU protected
 319  * access is good enough for this function.  Returns %true if a reference
 320  * count was successfully obtained; %false otherwise.
 321  */
 322 static inline bool css_tryget(struct cgroup_subsys_state *css)
 323 {
 324         if (!(css->flags & CSS_NO_REF))
 325                 return percpu_ref_tryget(&css->refcnt);
 326         return true;
 327 }
 328
 329 /**
 330  * css_tryget_online - try to obtain a reference on the specified css if online
 331  * @css: target css
 332  *
 333  * Obtain a reference on @css if it's online.  The caller naturally needs
 334  * to ensure that @css is accessible but doesn't have to be holding a
 335  * reference on it - IOW, RCU protected access is good enough for this
 336  * function.  Returns %true if a reference count was successfully obtained;
 337  * %false otherwise.
 338  */
 339 static inline bool css_tryget_online(struct cgroup_subsys_state *css)
 340 {
 341         if (!(css->flags & CSS_NO_REF))
 342                 return percpu_ref_tryget_live(&css->refcnt);
 343         return true;
 344 }
 345
 346 /**
 347  * css_put - put a css reference
 348  * @css: target css
 349  *
 350  * Put a reference obtained via css_get() and css_tryget_online().
 351  */
 352 static inline void css_put(struct cgroup_subsys_state *css)
 353 {
 354         if (!(css->flags & CSS_NO_REF))
 355                 percpu_ref_put(&css->refcnt);
 356 }
 357
 358 /**
 359  * css_put_many - put css references
 360  * @css: target css
 361  * @n: number of references to put
 362  *
 363  * Put references obtained via css_get() and css_tryget_online().
 364  */
 365 static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n)
 366 {
 367         if (!(css->flags & CSS_NO_REF))
 368                 percpu_ref_put_many(&css->refcnt, n);
 369 }
 370
 371 static inline void cgroup_put(struct cgroup *cgrp)
 372 {
 373         css_put(&cgrp->self);
 374 }
 375
 376 /**
 377  * task_css_set_check - obtain a task's css_set with extra access conditions
 378  * @task: the task to obtain css_set for
 379  * @__c: extra condition expression to be passed to rcu_dereference_check()
 380  *
 381  * A task's css_set is RCU protected, initialized and exited while holding
 382  * task_lock(), and can only be modified while holding both cgroup_mutex
 383  * and task_lock() while the task is alive.  This macro verifies that the
 384  * caller is inside proper critical section and returns @task's css_set.
 385  *
 386  * The caller can also specify additional allowed conditions via @__c, such
 387  * as locks used during the cgroup_subsys::attach() methods.
 388  */
 389 #ifdef CONFIG_PROVE_RCU
 390 extern struct mutex cgroup_mutex;
 391 extern spinlock_t css_set_lock;
 392 #define task_css_set_check(task, __c)                                   \
 393         rcu_dereference_check((task)->cgroups,                          \
 394                 lockdep_is_held(&cgroup_mutex) ||                       \
 395                 lockdep_is_held(&css_set_lock) ||                       \
 396                 ((task)->flags & PF_EXITING) || (__c))
 397 #else
 398 #define task_css_set_check(task, __c)                                   \
 399         rcu_dereference((task)->cgroups)
 400 #endif
 401
 402 /**
 403  * task_css_check - obtain css for (task, subsys) w/ extra access conds
 404  * @task: the target task
 405  * @subsys_id: the target subsystem ID
 406  * @__c: extra condition expression to be passed to rcu_dereference_check()
 407  *
 408  * Return the cgroup_subsys_state for the (@task, @subsys_id) pair.  The
 409  * synchronization rules are the same as task_css_set_check().
 410  */
 411 #define task_css_check(task, subsys_id, __c)                            \
 412         task_css_set_check((task), (__c))->subsys[(subsys_id)]
 413
 414 /**
 415  * task_css_set - obtain a task's css_set
 416  * @task: the task to obtain css_set for
 417  *
 418  * See task_css_set_check().
 419  */
 420 static inline struct css_set *task_css_set(struct task_struct *task)
 421 {
 422         return task_css_set_check(task, false);
 423 }
 424
 425 /**
 426  * task_css - obtain css for (task, subsys)
 427  * @task: the target task
 428  * @subsys_id: the target subsystem ID
 429  *
 430  * See task_css_check().
 431  */
 432 static inline struct cgroup_subsys_state *task_css(struct task_struct *task,
 433                                                    int subsys_id)
 434 {
 435         return task_css_check(task, subsys_id, false);
 436 }
 437
 438 /**
 439  * task_get_css - find and get the css for (task, subsys)
 440  * @task: the target task
 441  * @subsys_id: the target subsystem ID
 442  *
 443  * Find the css for the (@task, @subsys_id) combination, increment a
 444  * reference on and return it.  This function is guaranteed to return a
 445  * valid css.
 446  */
 447 static inline struct cgroup_subsys_state *
 448 task_get_css(struct task_struct *task, int subsys_id)
 449 {
 450         struct cgroup_subsys_state *css;
 451
 452         rcu_read_lock();
 453         while (true) {
 454                 css = task_css(task, subsys_id);
 455                 if (likely(css_tryget_online(css)))
 456                         break;
 457                 cpu_relax();
 458         }
 459         rcu_read_unlock();
 460         return css;
 461 }
 462
 463 /**
 464  * task_css_is_root - test whether a task belongs to the root css
 465  * @task: the target task
 466  * @subsys_id: the target subsystem ID
 467  *
 468  * Test whether @task belongs to the root css on the specified subsystem.
 469  * May be invoked in any context.
 470  */
 471 static inline bool task_css_is_root(struct task_struct *task, int subsys_id)
 472 {
 473         return task_css_check(task, subsys_id, true) ==
 474                 init_css_set.subsys[subsys_id];
 475 }
 476
 477 static inline struct cgroup *task_cgroup(struct task_struct *task,
 478                                          int subsys_id)
 479 {
 480         return task_css(task, subsys_id)->cgroup;
 481 }
 482
 483 /**
 484  * cgroup_is_descendant - test ancestry
 485  * @cgrp: the cgroup to be tested
 486  * @ancestor: possible ancestor of @cgrp
 487  *
 488  * Test whether @cgrp is a descendant of @ancestor.  It also returns %true
 489  * if @cgrp == @ancestor.  This function is safe to call as long as @cgrp
 490  * and @ancestor are accessible.
 491  */
 492 static inline bool cgroup_is_descendant(struct cgroup *cgrp,
 493                                         struct cgroup *ancestor)
 494 {
 495         if (cgrp->root != ancestor->root || cgrp->level < ancestor->level)
 496                 return false;
 497         return cgrp->ancestor_ids[ancestor->level] == ancestor->id;
 498 }
 499
 500 /**
 501  * task_under_cgroup_hierarchy - test task's membership of cgroup ancestry
 502  * @task: the task to be tested
 503  * @ancestor: possible ancestor of @task's cgroup
 504  *
 505  * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor.
 506  * It follows all the same rules as cgroup_is_descendant, and only applies
 507  * to the default hierarchy.
 508  */
 509 static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
 510                                                struct cgroup *ancestor)
 511 {
 512         struct css_set *cset = task_css_set(task);
 513
 514         return cgroup_is_descendant(cset->dfl_cgrp, ancestor);
 515 }
 516
 517 /* no synchronization, the result can only be used as a hint */
 518 static inline bool cgroup_is_populated(struct cgroup *cgrp)
 519 {
 520         return cgrp->populated_cnt;
 521 }
 522
 523 /* returns ino associated with a cgroup */
 524 static inline ino_t cgroup_ino(struct cgroup *cgrp)
 525 {
 526         return cgrp->kn->ino;
 527 }
 528
 529 /* cft/css accessors for cftype->write() operation */
 530 static inline struct cftype *of_cft(struct kernfs_open_file *of)
 531 {
 532         return of->kn->priv;
 533 }
 534
 535 struct cgroup_subsys_state *of_css(struct kernfs_open_file *of);
 536
 537 /* cft/css accessors for cftype->seq_*() operations */
 538 static inline struct cftype *seq_cft(struct seq_file *seq)
 539 {
 540         return of_cft(seq->private);
 541 }
 542
 543 static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq)
 544 {
 545         return of_css(seq->private);
 546 }
 547
 548 /*
 549  * Name / path handling functions.  All are thin wrappers around the kernfs
 550  * counterparts and can be called under any context.
 551  */
 552
 553 static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen)
 554 {
 555         return kernfs_name(cgrp->kn, buf, buflen);
 556 }
 557
 558 static inline int cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen)
 559 {
 560         return kernfs_path(cgrp->kn, buf, buflen);
 561 }
 562
 563 static inline void pr_cont_cgroup_name(struct cgroup *cgrp)
 564 {
 565         pr_cont_kernfs_name(cgrp->kn);
 566 }
 567
 568 static inline void pr_cont_cgroup_path(struct cgroup *cgrp)
 569 {
 570         pr_cont_kernfs_path(cgrp->kn);
 571 }
 572
 573 #else /* !CONFIG_CGROUPS */
 574
 575 struct cgroup_subsys_state;
 576 struct cgroup;
 577
 578 static inline void css_put(struct cgroup_subsys_state *css) {}
 579 static inline int cgroup_attach_task_all(struct task_struct *from,
 580                                          struct task_struct *t) { return 0; }
 581 static inline int cgroupstats_build(struct cgroupstats *stats,
 582                                     struct dentry *dentry) { return -EINVAL; }
 583
 584 static inline void cgroup_fork(struct task_struct *p) {}
 585 static inline int cgroup_can_fork(struct task_struct *p) { return 0; }
 586 static inline void cgroup_cancel_fork(struct task_struct *p) {}
 587 static inline void cgroup_post_fork(struct task_struct *p) {}
 588 static inline void cgroup_exit(struct task_struct *p) {}
 589 static inline void cgroup_free(struct task_struct *p) {}
 590
 591 static inline int cgroup_init_early(void) { return 0; }
 592 static inline int cgroup_init(void) { return 0; }
 593
 594 static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
 595                                                struct cgroup *ancestor)
 596 {
 597         return true;
 598 }
 599 #endif /* !CONFIG_CGROUPS */
 600
 601 /*
 602  * sock->sk_cgrp_data handling.  For more info, see sock_cgroup_data
 603  * definition in cgroup-defs.h.
 604  */
 605 #ifdef CONFIG_SOCK_CGROUP_DATA
 606
 607 #if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID)
 608 extern spinlock_t cgroup_sk_update_lock;
 609 #endif
 610
 611 void cgroup_sk_alloc_disable(void);
 612 void cgroup_sk_alloc(struct sock_cgroup_data *skcd);
 613 void cgroup_sk_free(struct sock_cgroup_data *skcd);
 614
 615 static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd)
 616 {
 617 #if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID)
 618         unsigned long v;
 619
 620         /*
 621          * @skcd->val is 64bit but the following is safe on 32bit too as we
 622          * just need the lower ulong to be written and read atomically.
 623          */
 624         v = READ_ONCE(skcd->val);
 625
 626         if (v & 1)
 627                 return &cgrp_dfl_root.cgrp;
 628
 629         return (struct cgroup *)(unsigned long)v ?: &cgrp_dfl_root.cgrp;
 630 #else
 631         return (struct cgroup *)(unsigned long)skcd->val;
 632 #endif
 633 }
 634
 635 #else   /* CONFIG_CGROUP_DATA */
 636
 637 static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {}
 638 static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {}
 639
 640 #endif  /* CONFIG_CGROUP_DATA */
 641
 642 struct cgroup_namespace {
 643         atomic_t                count;
 644         struct ns_common        ns;
 645         struct user_namespace   *user_ns;
 646         struct css_set          *root_cset;
 647 };
 648
 649 extern struct cgroup_namespace init_cgroup_ns;
 650
 651 #ifdef CONFIG_CGROUPS
 652
 653 void free_cgroup_ns(struct cgroup_namespace *ns);
 654
 655 struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,
 656                                         struct user_namespace *user_ns,
 657                                         struct cgroup_namespace *old_ns);
 658
 659 int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
 660                    struct cgroup_namespace *ns);
 661
 662 #else /* !CONFIG_CGROUPS */
 663
 664 static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
 665 static inline struct cgroup_namespace *
 666 copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
 667                struct cgroup_namespace *old_ns)
 668 {
 669         return old_ns;
 670 }
 671
 672 #endif /* !CONFIG_CGROUPS */
 673
 674 static inline void get_cgroup_ns(struct cgroup_namespace *ns)
 675 {
 676         if (ns)
 677                 atomic_inc(&ns->count);
 678 }
 679
 680 static inline void put_cgroup_ns(struct cgroup_namespace *ns)
 681 {
 682         if (ns && atomic_dec_and_test(&ns->count))
 683                 free_cgroup_ns(ns);
 684 }
 685
 686 #endif /* _LINUX_CGROUP_H */