~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/kernel/cgroup/cgroup-v1.c

Version: ~ [ linux-5.9 ] ~ [ linux-5.8.14 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.70 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.150 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.200 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.238 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.238 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: GPL-2.0-only
  2 #include "cgroup-internal.h"
  3 
  4 #include <linux/ctype.h>
  5 #include <linux/kmod.h>
  6 #include <linux/sort.h>
  7 #include <linux/delay.h>
  8 #include <linux/mm.h>
  9 #include <linux/sched/signal.h>
 10 #include <linux/sched/task.h>
 11 #include <linux/magic.h>
 12 #include <linux/slab.h>
 13 #include <linux/vmalloc.h>
 14 #include <linux/delayacct.h>
 15 #include <linux/pid_namespace.h>
 16 #include <linux/cgroupstats.h>
 17 #include <linux/fs_parser.h>
 18 
 19 #include <trace/events/cgroup.h>
 20 
 21 #define cg_invalf(fc, fmt, ...) invalf(fc, fmt, ## __VA_ARGS__)
 22 
 23 /*
 24  * pidlists linger the following amount before being destroyed.  The goal
 25  * is avoiding frequent destruction in the middle of consecutive read calls
 26  * Expiring in the middle is a performance problem not a correctness one.
 27  * 1 sec should be enough.
 28  */
 29 #define CGROUP_PIDLIST_DESTROY_DELAY    HZ
 30 
 31 /* Controllers blocked by the commandline in v1 */
 32 static u16 cgroup_no_v1_mask;
 33 
 34 /* disable named v1 mounts */
 35 static bool cgroup_no_v1_named;
 36 
 37 /*
 38  * pidlist destructions need to be flushed on cgroup destruction.  Use a
 39  * separate workqueue as flush domain.
 40  */
 41 static struct workqueue_struct *cgroup_pidlist_destroy_wq;
 42 
 43 /*
 44  * Protects cgroup_subsys->release_agent_path.  Modifying it also requires
 45  * cgroup_mutex.  Reading requires either cgroup_mutex or this spinlock.
 46  */
 47 static DEFINE_SPINLOCK(release_agent_path_lock);
 48 
 49 bool cgroup1_ssid_disabled(int ssid)
 50 {
 51         return cgroup_no_v1_mask & (1 << ssid);
 52 }
 53 
 54 /**
 55  * cgroup_attach_task_all - attach task 'tsk' to all cgroups of task 'from'
 56  * @from: attach to all cgroups of a given task
 57  * @tsk: the task to be attached
 58  */
 59 int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk)
 60 {
 61         struct cgroup_root *root;
 62         int retval = 0;
 63 
 64         mutex_lock(&cgroup_mutex);
 65         percpu_down_write(&cgroup_threadgroup_rwsem);
 66         for_each_root(root) {
 67                 struct cgroup *from_cgrp;
 68 
 69                 if (root == &cgrp_dfl_root)
 70                         continue;
 71 
 72                 spin_lock_irq(&css_set_lock);
 73                 from_cgrp = task_cgroup_from_root(from, root);
 74                 spin_unlock_irq(&css_set_lock);
 75 
 76                 retval = cgroup_attach_task(from_cgrp, tsk, false);
 77                 if (retval)
 78                         break;
 79         }
 80         percpu_up_write(&cgroup_threadgroup_rwsem);
 81         mutex_unlock(&cgroup_mutex);
 82 
 83         return retval;
 84 }
 85 EXPORT_SYMBOL_GPL(cgroup_attach_task_all);
 86 
 87 /**
 88  * cgroup_trasnsfer_tasks - move tasks from one cgroup to another
 89  * @to: cgroup to which the tasks will be moved
 90  * @from: cgroup in which the tasks currently reside
 91  *
 92  * Locking rules between cgroup_post_fork() and the migration path
 93  * guarantee that, if a task is forking while being migrated, the new child
 94  * is guaranteed to be either visible in the source cgroup after the
 95  * parent's migration is complete or put into the target cgroup.  No task
 96  * can slip out of migration through forking.
 97  */
 98 int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from)
 99 {
100         DEFINE_CGROUP_MGCTX(mgctx);
101         struct cgrp_cset_link *link;
102         struct css_task_iter it;
103         struct task_struct *task;
104         int ret;
105 
106         if (cgroup_on_dfl(to))
107                 return -EINVAL;
108 
109         ret = cgroup_migrate_vet_dst(to);
110         if (ret)
111                 return ret;
112 
113         mutex_lock(&cgroup_mutex);
114 
115         percpu_down_write(&cgroup_threadgroup_rwsem);
116 
117         /* all tasks in @from are being moved, all csets are source */
118         spin_lock_irq(&css_set_lock);
119         list_for_each_entry(link, &from->cset_links, cset_link)
120                 cgroup_migrate_add_src(link->cset, to, &mgctx);
121         spin_unlock_irq(&css_set_lock);
122 
123         ret = cgroup_migrate_prepare_dst(&mgctx);
124         if (ret)
125                 goto out_err;
126 
127         /*
128          * Migrate tasks one-by-one until @from is empty.  This fails iff
129          * ->can_attach() fails.
130          */
131         do {
132                 css_task_iter_start(&from->self, 0, &it);
133 
134                 do {
135                         task = css_task_iter_next(&it);
136                 } while (task && (task->flags & PF_EXITING));
137 
138                 if (task)
139                         get_task_struct(task);
140                 css_task_iter_end(&it);
141 
142                 if (task) {
143                         ret = cgroup_migrate(task, false, &mgctx);
144                         if (!ret)
145                                 TRACE_CGROUP_PATH(transfer_tasks, to, task, false);
146                         put_task_struct(task);
147                 }
148         } while (task && !ret);
149 out_err:
150         cgroup_migrate_finish(&mgctx);
151         percpu_up_write(&cgroup_threadgroup_rwsem);
152         mutex_unlock(&cgroup_mutex);
153         return ret;
154 }
155 
156 /*
157  * Stuff for reading the 'tasks'/'procs' files.
158  *
159  * Reading this file can return large amounts of data if a cgroup has
160  * *lots* of attached tasks. So it may need several calls to read(),
161  * but we cannot guarantee that the information we produce is correct
162  * unless we produce it entirely atomically.
163  *
164  */
165 
166 /* which pidlist file are we talking about? */
167 enum cgroup_filetype {
168         CGROUP_FILE_PROCS,
169         CGROUP_FILE_TASKS,
170 };
171 
172 /*
173  * A pidlist is a list of pids that virtually represents the contents of one
174  * of the cgroup files ("procs" or "tasks"). We keep a list of such pidlists,
175  * a pair (one each for procs, tasks) for each pid namespace that's relevant
176  * to the cgroup.
177  */
178 struct cgroup_pidlist {
179         /*
180          * used to find which pidlist is wanted. doesn't change as long as
181          * this particular list stays in the list.
182         */
183         struct { enum cgroup_filetype type; struct pid_namespace *ns; } key;
184         /* array of xids */
185         pid_t *list;
186         /* how many elements the above list has */
187         int length;
188         /* each of these stored in a list by its cgroup */
189         struct list_head links;
190         /* pointer to the cgroup we belong to, for list removal purposes */
191         struct cgroup *owner;
192         /* for delayed destruction */
193         struct delayed_work destroy_dwork;
194 };
195 
196 /*
197  * The following two functions "fix" the issue where there are more pids
198  * than kmalloc will give memory for; in such cases, we use vmalloc/vfree.
199  * TODO: replace with a kernel-wide solution to this problem
200  */
201 #define PIDLIST_TOO_LARGE(c) ((c) * sizeof(pid_t) > (PAGE_SIZE * 2))
202 static void *pidlist_allocate(int count)
203 {
204         if (PIDLIST_TOO_LARGE(count))
205                 return vmalloc(array_size(count, sizeof(pid_t)));
206         else
207                 return kmalloc_array(count, sizeof(pid_t), GFP_KERNEL);
208 }
209 
210 static void pidlist_free(void *p)
211 {
212         kvfree(p);
213 }
214 
215 /*
216  * Used to destroy all pidlists lingering waiting for destroy timer.  None
217  * should be left afterwards.
218  */
219 void cgroup1_pidlist_destroy_all(struct cgroup *cgrp)
220 {
221         struct cgroup_pidlist *l, *tmp_l;
222 
223         mutex_lock(&cgrp->pidlist_mutex);
224         list_for_each_entry_safe(l, tmp_l, &cgrp->pidlists, links)
225                 mod_delayed_work(cgroup_pidlist_destroy_wq, &l->destroy_dwork, 0);
226         mutex_unlock(&cgrp->pidlist_mutex);
227 
228         flush_workqueue(cgroup_pidlist_destroy_wq);
229         BUG_ON(!list_empty(&cgrp->pidlists));
230 }
231 
232 static void cgroup_pidlist_destroy_work_fn(struct work_struct *work)
233 {
234         struct delayed_work *dwork = to_delayed_work(work);
235         struct cgroup_pidlist *l = container_of(dwork, struct cgroup_pidlist,
236                                                 destroy_dwork);
237         struct cgroup_pidlist *tofree = NULL;
238 
239         mutex_lock(&l->owner->pidlist_mutex);
240 
241         /*
242          * Destroy iff we didn't get queued again.  The state won't change
243          * as destroy_dwork can only be queued while locked.
244          */
245         if (!delayed_work_pending(dwork)) {
246                 list_del(&l->links);
247                 pidlist_free(l->list);
248                 put_pid_ns(l->key.ns);
249                 tofree = l;
250         }
251 
252         mutex_unlock(&l->owner->pidlist_mutex);
253         kfree(tofree);
254 }
255 
256 /*
257  * pidlist_uniq - given a kmalloc()ed list, strip out all duplicate entries
258  * Returns the number of unique elements.
259  */
260 static int pidlist_uniq(pid_t *list, int length)
261 {
262         int src, dest = 1;
263 
264         /*
265          * we presume the 0th element is unique, so i starts at 1. trivial
266          * edge cases first; no work needs to be done for either
267          */
268         if (length == 0 || length == 1)
269                 return length;
270         /* src and dest walk down the list; dest counts unique elements */
271         for (src = 1; src < length; src++) {
272                 /* find next unique element */
273                 while (list[src] == list[src-1]) {
274                         src++;
275                         if (src == length)
276                                 goto after;
277                 }
278                 /* dest always points to where the next unique element goes */
279                 list[dest] = list[src];
280                 dest++;
281         }
282 after:
283         return dest;
284 }
285 
286 /*
287  * The two pid files - task and cgroup.procs - guaranteed that the result
288  * is sorted, which forced this whole pidlist fiasco.  As pid order is
289  * different per namespace, each namespace needs differently sorted list,
290  * making it impossible to use, for example, single rbtree of member tasks
291  * sorted by task pointer.  As pidlists can be fairly large, allocating one
292  * per open file is dangerous, so cgroup had to implement shared pool of
293  * pidlists keyed by cgroup and namespace.
294  */
295 static int cmppid(const void *a, const void *b)
296 {
297         return *(pid_t *)a - *(pid_t *)b;
298 }
299 
300 static struct cgroup_pidlist *cgroup_pidlist_find(struct cgroup *cgrp,
301                                                   enum cgroup_filetype type)
302 {
303         struct cgroup_pidlist *l;
304         /* don't need task_nsproxy() if we're looking at ourself */
305         struct pid_namespace *ns = task_active_pid_ns(current);
306 
307         lockdep_assert_held(&cgrp->pidlist_mutex);
308 
309         list_for_each_entry(l, &cgrp->pidlists, links)
310                 if (l->key.type == type && l->key.ns == ns)
311                         return l;
312         return NULL;
313 }
314 
315 /*
316  * find the appropriate pidlist for our purpose (given procs vs tasks)
317  * returns with the lock on that pidlist already held, and takes care
318  * of the use count, or returns NULL with no locks held if we're out of
319  * memory.
320  */
321 static struct cgroup_pidlist *cgroup_pidlist_find_create(struct cgroup *cgrp,
322                                                 enum cgroup_filetype type)
323 {
324         struct cgroup_pidlist *l;
325 
326         lockdep_assert_held(&cgrp->pidlist_mutex);
327 
328         l = cgroup_pidlist_find(cgrp, type);
329         if (l)
330                 return l;
331 
332         /* entry not found; create a new one */
333         l = kzalloc(sizeof(struct cgroup_pidlist), GFP_KERNEL);
334         if (!l)
335                 return l;
336 
337         INIT_DELAYED_WORK(&l->destroy_dwork, cgroup_pidlist_destroy_work_fn);
338         l->key.type = type;
339         /* don't need task_nsproxy() if we're looking at ourself */
340         l->key.ns = get_pid_ns(task_active_pid_ns(current));
341         l->owner = cgrp;
342         list_add(&l->links, &cgrp->pidlists);
343         return l;
344 }
345 
346 /*
347  * Load a cgroup's pidarray with either procs' tgids or tasks' pids
348  */
349 static int pidlist_array_load(struct cgroup *cgrp, enum cgroup_filetype type,
350                               struct cgroup_pidlist **lp)
351 {
352         pid_t *array;
353         int length;
354         int pid, n = 0; /* used for populating the array */
355         struct css_task_iter it;
356         struct task_struct *tsk;
357         struct cgroup_pidlist *l;
358 
359         lockdep_assert_held(&cgrp->pidlist_mutex);
360 
361         /*
362          * If cgroup gets more users after we read count, we won't have
363          * enough space - tough.  This race is indistinguishable to the
364          * caller from the case that the additional cgroup users didn't
365          * show up until sometime later on.
366          */
367         length = cgroup_task_count(cgrp);
368         array = pidlist_allocate(length);
369         if (!array)
370                 return -ENOMEM;
371         /* now, populate the array */
372         css_task_iter_start(&cgrp->self, 0, &it);
373         while ((tsk = css_task_iter_next(&it))) {
374                 if (unlikely(n == length))
375                         break;
376                 /* get tgid or pid for procs or tasks file respectively */
377                 if (type == CGROUP_FILE_PROCS)
378                         pid = task_tgid_vnr(tsk);
379                 else
380                         pid = task_pid_vnr(tsk);
381                 if (pid > 0) /* make sure to only use valid results */
382                         array[n++] = pid;
383         }
384         css_task_iter_end(&it);
385         length = n;
386         /* now sort & (if procs) strip out duplicates */
387         sort(array, length, sizeof(pid_t), cmppid, NULL);
388         if (type == CGROUP_FILE_PROCS)
389                 length = pidlist_uniq(array, length);
390 
391         l = cgroup_pidlist_find_create(cgrp, type);
392         if (!l) {
393                 pidlist_free(array);
394                 return -ENOMEM;
395         }
396 
397         /* store array, freeing old if necessary */
398         pidlist_free(l->list);
399         l->list = array;
400         l->length = length;
401         *lp = l;
402         return 0;
403 }
404 
405 /*
406  * seq_file methods for the tasks/procs files. The seq_file position is the
407  * next pid to display; the seq_file iterator is a pointer to the pid
408  * in the cgroup->l->list array.
409  */
410 
411 static void *cgroup_pidlist_start(struct seq_file *s, loff_t *pos)
412 {
413         /*
414          * Initially we receive a position value that corresponds to
415          * one more than the last pid shown (or 0 on the first call or
416          * after a seek to the start). Use a binary-search to find the
417          * next pid to display, if any
418          */
419         struct kernfs_open_file *of = s->private;
420         struct cgroup *cgrp = seq_css(s)->cgroup;
421         struct cgroup_pidlist *l;
422         enum cgroup_filetype type = seq_cft(s)->private;
423         int index = 0, pid = *pos;
424         int *iter, ret;
425 
426         mutex_lock(&cgrp->pidlist_mutex);
427 
428         /*
429          * !NULL @of->priv indicates that this isn't the first start()
430          * after open.  If the matching pidlist is around, we can use that.
431          * Look for it.  Note that @of->priv can't be used directly.  It
432          * could already have been destroyed.
433          */
434         if (of->priv)
435                 of->priv = cgroup_pidlist_find(cgrp, type);
436 
437         /*
438          * Either this is the first start() after open or the matching
439          * pidlist has been destroyed inbetween.  Create a new one.
440          */
441         if (!of->priv) {
442                 ret = pidlist_array_load(cgrp, type,
443                                          (struct cgroup_pidlist **)&of->priv);
444                 if (ret)
445                         return ERR_PTR(ret);
446         }
447         l = of->priv;
448 
449         if (pid) {
450                 int end = l->length;
451 
452                 while (index < end) {
453                         int mid = (index + end) / 2;
454                         if (l->list[mid] == pid) {
455                                 index = mid;
456                                 break;
457                         } else if (l->list[mid] <= pid)
458                                 index = mid + 1;
459                         else
460                                 end = mid;
461                 }
462         }
463         /* If we're off the end of the array, we're done */
464         if (index >= l->length)
465                 return NULL;
466         /* Update the abstract position to be the actual pid that we found */
467         iter = l->list + index;
468         *pos = *iter;
469         return iter;
470 }
471 
472 static void cgroup_pidlist_stop(struct seq_file *s, void *v)
473 {
474         struct kernfs_open_file *of = s->private;
475         struct cgroup_pidlist *l = of->priv;
476 
477         if (l)
478                 mod_delayed_work(cgroup_pidlist_destroy_wq, &l->destroy_dwork,
479                                  CGROUP_PIDLIST_DESTROY_DELAY);
480         mutex_unlock(&seq_css(s)->cgroup->pidlist_mutex);
481 }
482 
483 static void *cgroup_pidlist_next(struct seq_file *s, void *v, loff_t *pos)
484 {
485         struct kernfs_open_file *of = s->private;
486         struct cgroup_pidlist *l = of->priv;
487         pid_t *p = v;
488         pid_t *end = l->list + l->length;
489         /*
490          * Advance to the next pid in the array. If this goes off the
491          * end, we're done
492          */
493         p++;
494         if (p >= end) {
495                 return NULL;
496         } else {
497                 *pos = *p;
498                 return p;
499         }
500 }
501 
502 static int cgroup_pidlist_show(struct seq_file *s, void *v)
503 {
504         seq_printf(s, "%d\n", *(int *)v);
505 
506         return 0;
507 }
508 
509 static ssize_t __cgroup1_procs_write(struct kernfs_open_file *of,
510                                      char *buf, size_t nbytes, loff_t off,
511                                      bool threadgroup)
512 {
513         struct cgroup *cgrp;
514         struct task_struct *task;
515         const struct cred *cred, *tcred;
516         ssize_t ret;
517 
518         cgrp = cgroup_kn_lock_live(of->kn, false);
519         if (!cgrp)
520                 return -ENODEV;
521 
522         task = cgroup_procs_write_start(buf, threadgroup);
523         ret = PTR_ERR_OR_ZERO(task);
524         if (ret)
525                 goto out_unlock;
526 
527         /*
528          * Even if we're attaching all tasks in the thread group, we only
529          * need to check permissions on one of them.
530          */
531         cred = current_cred();
532         tcred = get_task_cred(task);
533         if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) &&
534             !uid_eq(cred->euid, tcred->uid) &&
535             !uid_eq(cred->euid, tcred->suid))
536                 ret = -EACCES;
537         put_cred(tcred);
538         if (ret)
539                 goto out_finish;
540 
541         ret = cgroup_attach_task(cgrp, task, threadgroup);
542 
543 out_finish:
544         cgroup_procs_write_finish(task);
545 out_unlock:
546         cgroup_kn_unlock(of->kn);
547 
548         return ret ?: nbytes;
549 }
550 
551 static ssize_t cgroup1_procs_write(struct kernfs_open_file *of,
552                                    char *buf, size_t nbytes, loff_t off)
553 {
554         return __cgroup1_procs_write(of, buf, nbytes, off, true);
555 }
556 
557 static ssize_t cgroup1_tasks_write(struct kernfs_open_file *of,
558                                    char *buf, size_t nbytes, loff_t off)
559 {
560         return __cgroup1_procs_write(of, buf, nbytes, off, false);
561 }
562 
563 static ssize_t cgroup_release_agent_write(struct kernfs_open_file *of,
564                                           char *buf, size_t nbytes, loff_t off)
565 {
566         struct cgroup *cgrp;
567 
568         BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX);
569 
570         cgrp = cgroup_kn_lock_live(of->kn, false);
571         if (!cgrp)
572                 return -ENODEV;
573         spin_lock(&release_agent_path_lock);
574         strlcpy(cgrp->root->release_agent_path, strstrip(buf),
575                 sizeof(cgrp->root->release_agent_path));
576         spin_unlock(&release_agent_path_lock);
577         cgroup_kn_unlock(of->kn);
578         return nbytes;
579 }
580 
581 static int cgroup_release_agent_show(struct seq_file *seq, void *v)
582 {
583         struct cgroup *cgrp = seq_css(seq)->cgroup;
584 
585         spin_lock(&release_agent_path_lock);
586         seq_puts(seq, cgrp->root->release_agent_path);
587         spin_unlock(&release_agent_path_lock);
588         seq_putc(seq, '\n');
589         return 0;
590 }
591 
592 static int cgroup_sane_behavior_show(struct seq_file *seq, void *v)
593 {
594         seq_puts(seq, "\n");
595         return 0;
596 }
597 
598 static u64 cgroup_read_notify_on_release(struct cgroup_subsys_state *css,
599                                          struct cftype *cft)
600 {
601         return notify_on_release(css->cgroup);
602 }
603 
604 static int cgroup_write_notify_on_release(struct cgroup_subsys_state *css,
605                                           struct cftype *cft, u64 val)
606 {
607         if (val)
608                 set_bit(CGRP_NOTIFY_ON_RELEASE, &css->cgroup->flags);
609         else
610                 clear_bit(CGRP_NOTIFY_ON_RELEASE, &css->cgroup->flags);
611         return 0;
612 }
613 
614 static u64 cgroup_clone_children_read(struct cgroup_subsys_state *css,
615                                       struct cftype *cft)
616 {
617         return test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
618 }
619 
620 static int cgroup_clone_children_write(struct cgroup_subsys_state *css,
621                                        struct cftype *cft, u64 val)
622 {
623         if (val)
624                 set_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
625         else
626                 clear_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
627         return 0;
628 }
629 
630 /* cgroup core interface files for the legacy hierarchies */
631 struct cftype cgroup1_base_files[] = {
632         {
633                 .name = "cgroup.procs",
634                 .seq_start = cgroup_pidlist_start,
635                 .seq_next = cgroup_pidlist_next,
636                 .seq_stop = cgroup_pidlist_stop,
637                 .seq_show = cgroup_pidlist_show,
638                 .private = CGROUP_FILE_PROCS,
639                 .write = cgroup1_procs_write,
640         },
641         {
642                 .name = "cgroup.clone_children",
643                 .read_u64 = cgroup_clone_children_read,
644                 .write_u64 = cgroup_clone_children_write,
645         },
646         {
647                 .name = "cgroup.sane_behavior",
648                 .flags = CFTYPE_ONLY_ON_ROOT,
649                 .seq_show = cgroup_sane_behavior_show,
650         },
651         {
652                 .name = "tasks",
653                 .seq_start = cgroup_pidlist_start,
654                 .seq_next = cgroup_pidlist_next,
655                 .seq_stop = cgroup_pidlist_stop,
656                 .seq_show = cgroup_pidlist_show,
657                 .private = CGROUP_FILE_TASKS,
658                 .write = cgroup1_tasks_write,
659         },
660         {
661                 .name = "notify_on_release",
662                 .read_u64 = cgroup_read_notify_on_release,
663                 .write_u64 = cgroup_write_notify_on_release,
664         },
665         {
666                 .name = "release_agent",
667                 .flags = CFTYPE_ONLY_ON_ROOT,
668                 .seq_show = cgroup_release_agent_show,
669                 .write = cgroup_release_agent_write,
670                 .max_write_len = PATH_MAX - 1,
671         },
672         { }     /* terminate */
673 };
674 
675 /* Display information about each subsystem and each hierarchy */
676 int proc_cgroupstats_show(struct seq_file *m, void *v)
677 {
678         struct cgroup_subsys *ss;
679         int i;
680 
681         seq_puts(m, "#subsys_name\thierarchy\tnum_cgroups\tenabled\n");
682         /*
683          * ideally we don't want subsystems moving around while we do this.
684          * cgroup_mutex is also necessary to guarantee an atomic snapshot of
685          * subsys/hierarchy state.
686          */
687         mutex_lock(&cgroup_mutex);
688 
689         for_each_subsys(ss, i)
690                 seq_printf(m, "%s\t%d\t%d\t%d\n",
691                            ss->legacy_name, ss->root->hierarchy_id,
692                            atomic_read(&ss->root->nr_cgrps),
693                            cgroup_ssid_enabled(i));
694 
695         mutex_unlock(&cgroup_mutex);
696         return 0;
697 }
698 
699 /**
700  * cgroupstats_build - build and fill cgroupstats
701  * @stats: cgroupstats to fill information into
702  * @dentry: A dentry entry belonging to the cgroup for which stats have
703  * been requested.
704  *
705  * Build and fill cgroupstats so that taskstats can export it to user
706  * space.
707  */
708 int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
709 {
710         struct kernfs_node *kn = kernfs_node_from_dentry(dentry);
711         struct cgroup *cgrp;
712         struct css_task_iter it;
713         struct task_struct *tsk;
714 
715         /* it should be kernfs_node belonging to cgroupfs and is a directory */
716         if (dentry->d_sb->s_type != &cgroup_fs_type || !kn ||
717             kernfs_type(kn) != KERNFS_DIR)
718                 return -EINVAL;
719 
720         mutex_lock(&cgroup_mutex);
721 
722         /*
723          * We aren't being called from kernfs and there's no guarantee on
724          * @kn->priv's validity.  For this and css_tryget_online_from_dir(),
725          * @kn->priv is RCU safe.  Let's do the RCU dancing.
726          */
727         rcu_read_lock();
728         cgrp = rcu_dereference(*(void __rcu __force **)&kn->priv);
729         if (!cgrp || cgroup_is_dead(cgrp)) {
730                 rcu_read_unlock();
731                 mutex_unlock(&cgroup_mutex);
732                 return -ENOENT;
733         }
734         rcu_read_unlock();
735 
736         css_task_iter_start(&cgrp->self, 0, &it);
737         while ((tsk = css_task_iter_next(&it))) {
738                 switch (tsk->state) {
739                 case TASK_RUNNING:
740                         stats->nr_running++;
741                         break;
742                 case TASK_INTERRUPTIBLE:
743                         stats->nr_sleeping++;
744                         break;
745                 case TASK_UNINTERRUPTIBLE:
746                         stats->nr_uninterruptible++;
747                         break;
748                 case TASK_STOPPED:
749                         stats->nr_stopped++;
750                         break;
751                 default:
752                         if (delayacct_is_task_waiting_on_io(tsk))
753                                 stats->nr_io_wait++;
754                         break;
755                 }
756         }
757         css_task_iter_end(&it);
758 
759         mutex_unlock(&cgroup_mutex);
760         return 0;
761 }
762 
763 void cgroup1_check_for_release(struct cgroup *cgrp)
764 {
765         if (notify_on_release(cgrp) && !cgroup_is_populated(cgrp) &&
766             !css_has_online_children(&cgrp->self) && !cgroup_is_dead(cgrp))
767                 schedule_work(&cgrp->release_agent_work);
768 }
769 
770 /*
771  * Notify userspace when a cgroup is released, by running the
772  * configured release agent with the name of the cgroup (path
773  * relative to the root of cgroup file system) as the argument.
774  *
775  * Most likely, this user command will try to rmdir this cgroup.
776  *
777  * This races with the possibility that some other task will be
778  * attached to this cgroup before it is removed, or that some other
779  * user task will 'mkdir' a child cgroup of this cgroup.  That's ok.
780  * The presumed 'rmdir' will fail quietly if this cgroup is no longer
781  * unused, and this cgroup will be reprieved from its death sentence,
782  * to continue to serve a useful existence.  Next time it's released,
783  * we will get notified again, if it still has 'notify_on_release' set.
784  *
785  * The final arg to call_usermodehelper() is UMH_WAIT_EXEC, which
786  * means only wait until the task is successfully execve()'d.  The
787  * separate release agent task is forked by call_usermodehelper(),
788  * then control in this thread returns here, without waiting for the
789  * release agent task.  We don't bother to wait because the caller of
790  * this routine has no use for the exit status of the release agent
791  * task, so no sense holding our caller up for that.
792  */
793 void cgroup1_release_agent(struct work_struct *work)
794 {
795         struct cgroup *cgrp =
796                 container_of(work, struct cgroup, release_agent_work);
797         char *pathbuf = NULL, *agentbuf = NULL;
798         char *argv[3], *envp[3];
799         int ret;
800 
801         mutex_lock(&cgroup_mutex);
802 
803         pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
804         agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL);
805         if (!pathbuf || !agentbuf)
806                 goto out;
807 
808         spin_lock_irq(&css_set_lock);
809         ret = cgroup_path_ns_locked(cgrp, pathbuf, PATH_MAX, &init_cgroup_ns);
810         spin_unlock_irq(&css_set_lock);
811         if (ret < 0 || ret >= PATH_MAX)
812                 goto out;
813 
814         argv[0] = agentbuf;
815         argv[1] = pathbuf;
816         argv[2] = NULL;
817 
818         /* minimal command environment */
819         envp[0] = "HOME=/";
820         envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
821         envp[2] = NULL;
822 
823         mutex_unlock(&cgroup_mutex);
824         call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
825         goto out_free;
826 out:
827         mutex_unlock(&cgroup_mutex);
828 out_free:
829         kfree(agentbuf);
830         kfree(pathbuf);
831 }
832 
833 /*
834  * cgroup_rename - Only allow simple rename of directories in place.
835  */
836 static int cgroup1_rename(struct kernfs_node *kn, struct kernfs_node *new_parent,
837                           const char *new_name_str)
838 {
839         struct cgroup *cgrp = kn->priv;
840         int ret;
841 
842         if (kernfs_type(kn) != KERNFS_DIR)
843                 return -ENOTDIR;
844         if (kn->parent != new_parent)
845                 return -EIO;
846 
847         /*
848          * We're gonna grab cgroup_mutex which nests outside kernfs
849          * active_ref.  kernfs_rename() doesn't require active_ref
850          * protection.  Break them before grabbing cgroup_mutex.
851          */
852         kernfs_break_active_protection(new_parent);
853         kernfs_break_active_protection(kn);
854 
855         mutex_lock(&cgroup_mutex);
856 
857         ret = kernfs_rename(kn, new_parent, new_name_str);
858         if (!ret)
859                 TRACE_CGROUP_PATH(rename, cgrp);
860 
861         mutex_unlock(&cgroup_mutex);
862 
863         kernfs_unbreak_active_protection(kn);
864         kernfs_unbreak_active_protection(new_parent);
865         return ret;
866 }
867 
868 static int cgroup1_show_options(struct seq_file *seq, struct kernfs_root *kf_root)
869 {
870         struct cgroup_root *root = cgroup_root_from_kf(kf_root);
871         struct cgroup_subsys *ss;
872         int ssid;
873 
874         for_each_subsys(ss, ssid)
875                 if (root->subsys_mask & (1 << ssid))
876                         seq_show_option(seq, ss->legacy_name, NULL);
877         if (root->flags & CGRP_ROOT_NOPREFIX)
878                 seq_puts(seq, ",noprefix");
879         if (root->flags & CGRP_ROOT_XATTR)
880                 seq_puts(seq, ",xattr");
881         if (root->flags & CGRP_ROOT_CPUSET_V2_MODE)
882                 seq_puts(seq, ",cpuset_v2_mode");
883 
884         spin_lock(&release_agent_path_lock);
885         if (strlen(root->release_agent_path))
886                 seq_show_option(seq, "release_agent",
887                                 root->release_agent_path);
888         spin_unlock(&release_agent_path_lock);
889 
890         if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags))
891                 seq_puts(seq, ",clone_children");
892         if (strlen(root->name))
893                 seq_show_option(seq, "name", root->name);
894         return 0;
895 }
896 
897 enum cgroup1_param {
898         Opt_all,
899         Opt_clone_children,
900         Opt_cpuset_v2_mode,
901         Opt_name,
902         Opt_none,
903         Opt_noprefix,
904         Opt_release_agent,
905         Opt_xattr,
906 };
907 
908 static const struct fs_parameter_spec cgroup1_param_specs[] = {
909         fsparam_flag  ("all",           Opt_all),
910         fsparam_flag  ("clone_children", Opt_clone_children),
911         fsparam_flag  ("cpuset_v2_mode", Opt_cpuset_v2_mode),
912         fsparam_string("name",          Opt_name),
913         fsparam_flag  ("none",          Opt_none),
914         fsparam_flag  ("noprefix",      Opt_noprefix),
915         fsparam_string("release_agent", Opt_release_agent),
916         fsparam_flag  ("xattr",         Opt_xattr),
917         {}
918 };
919 
920 const struct fs_parameter_description cgroup1_fs_parameters = {
921         .name           = "cgroup1",
922         .specs          = cgroup1_param_specs,
923 };
924 
925 int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param)
926 {
927         struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
928         struct cgroup_subsys *ss;
929         struct fs_parse_result result;
930         int opt, i;
931 
932         opt = fs_parse(fc, &cgroup1_fs_parameters, param, &result);
933         if (opt == -ENOPARAM) {
934                 if (strcmp(param->key, "source") == 0) {
935                         fc->source = param->string;
936                         param->string = NULL;
937                         return 0;
938                 }
939                 for_each_subsys(ss, i) {
940                         if (strcmp(param->key, ss->legacy_name))
941                                 continue;
942                         ctx->subsys_mask |= (1 << i);
943                         return 0;
944                 }
945                 return cg_invalf(fc, "cgroup1: Unknown subsys name '%s'", param->key);
946         }
947         if (opt < 0)
948                 return opt;
949 
950         switch (opt) {
951         case Opt_none:
952                 /* Explicitly have no subsystems */
953                 ctx->none = true;
954                 break;
955         case Opt_all:
956                 ctx->all_ss = true;
957                 break;
958         case Opt_noprefix:
959                 ctx->flags |= CGRP_ROOT_NOPREFIX;
960                 break;
961         case Opt_clone_children:
962                 ctx->cpuset_clone_children = true;
963                 break;
964         case Opt_cpuset_v2_mode:
965                 ctx->flags |= CGRP_ROOT_CPUSET_V2_MODE;
966                 break;
967         case Opt_xattr:
968                 ctx->flags |= CGRP_ROOT_XATTR;
969                 break;
970         case Opt_release_agent:
971                 /* Specifying two release agents is forbidden */
972                 if (ctx->release_agent)
973                         return cg_invalf(fc, "cgroup1: release_agent respecified");
974                 ctx->release_agent = param->string;
975                 param->string = NULL;
976                 break;
977         case Opt_name:
978                 /* blocked by boot param? */
979                 if (cgroup_no_v1_named)
980                         return -ENOENT;
981                 /* Can't specify an empty name */
982                 if (!param->size)
983                         return cg_invalf(fc, "cgroup1: Empty name");
984                 if (param->size > MAX_CGROUP_ROOT_NAMELEN - 1)
985                         return cg_invalf(fc, "cgroup1: Name too long");
986                 /* Must match [\w.-]+ */
987                 for (i = 0; i < param->size; i++) {
988                         char c = param->string[i];
989                         if (isalnum(c))
990                                 continue;
991                         if ((c == '.') || (c == '-') || (c == '_'))
992                                 continue;
993                         return cg_invalf(fc, "cgroup1: Invalid name");
994                 }
995                 /* Specifying two names is forbidden */
996                 if (ctx->name)
997                         return cg_invalf(fc, "cgroup1: name respecified");
998                 ctx->name = param->string;
999                 param->string = NULL;
1000                 break;
1001         }
1002         return 0;
1003 }
1004 
1005 static int check_cgroupfs_options(struct fs_context *fc)
1006 {
1007         struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
1008         u16 mask = U16_MAX;
1009         u16 enabled = 0;
1010         struct cgroup_subsys *ss;
1011         int i;
1012 
1013 #ifdef CONFIG_CPUSETS
1014         mask = ~((u16)1 << cpuset_cgrp_id);
1015 #endif
1016         for_each_subsys(ss, i)
1017                 if (cgroup_ssid_enabled(i) && !cgroup1_ssid_disabled(i))
1018                         enabled |= 1 << i;
1019 
1020         ctx->subsys_mask &= enabled;
1021 
1022         /*
1023          * In absense of 'none', 'name=' or subsystem name options,
1024          * let's default to 'all'.
1025          */
1026         if (!ctx->subsys_mask && !ctx->none && !ctx->name)
1027                 ctx->all_ss = true;
1028 
1029         if (ctx->all_ss) {
1030                 /* Mutually exclusive option 'all' + subsystem name */
1031                 if (ctx->subsys_mask)
1032                         return cg_invalf(fc, "cgroup1: subsys name conflicts with all");
1033                 /* 'all' => select all the subsystems */
1034                 ctx->subsys_mask = enabled;
1035         }
1036 
1037         /*
1038          * We either have to specify by name or by subsystems. (So all
1039          * empty hierarchies must have a name).
1040          */
1041         if (!ctx->subsys_mask && !ctx->name)
1042                 return cg_invalf(fc, "cgroup1: Need name or subsystem set");
1043 
1044         /*
1045          * Option noprefix was introduced just for backward compatibility
1046          * with the old cpuset, so we allow noprefix only if mounting just
1047          * the cpuset subsystem.
1048          */
1049         if ((ctx->flags & CGRP_ROOT_NOPREFIX) && (ctx->subsys_mask & mask))
1050                 return cg_invalf(fc, "cgroup1: noprefix used incorrectly");
1051 
1052         /* Can't specify "none" and some subsystems */
1053         if (ctx->subsys_mask && ctx->none)
1054                 return cg_invalf(fc, "cgroup1: none used incorrectly");
1055 
1056         return 0;
1057 }
1058 
1059 int cgroup1_reconfigure(struct fs_context *fc)
1060 {
1061         struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
1062         struct kernfs_root *kf_root = kernfs_root_from_sb(fc->root->d_sb);
1063         struct cgroup_root *root = cgroup_root_from_kf(kf_root);
1064         int ret = 0;
1065         u16 added_mask, removed_mask;
1066 
1067         cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
1068 
1069         /* See what subsystems are wanted */
1070         ret = check_cgroupfs_options(fc);
1071         if (ret)
1072                 goto out_unlock;
1073 
1074         if (ctx->subsys_mask != root->subsys_mask || ctx->release_agent)
1075                 pr_warn("option changes via remount are deprecated (pid=%d comm=%s)\n",
1076                         task_tgid_nr(current), current->comm);
1077 
1078         added_mask = ctx->subsys_mask & ~root->subsys_mask;
1079         removed_mask = root->subsys_mask & ~ctx->subsys_mask;
1080 
1081         /* Don't allow flags or name to change at remount */
1082         if ((ctx->flags ^ root->flags) ||
1083             (ctx->name && strcmp(ctx->name, root->name))) {
1084                 cg_invalf(fc, "option or name mismatch, new: 0x%x \"%s\", old: 0x%x \"%s\"",
1085                        ctx->flags, ctx->name ?: "", root->flags, root->name);
1086                 ret = -EINVAL;
1087                 goto out_unlock;
1088         }
1089 
1090         /* remounting is not allowed for populated hierarchies */
1091         if (!list_empty(&root->cgrp.self.children)) {
1092                 ret = -EBUSY;
1093                 goto out_unlock;
1094         }
1095 
1096         ret = rebind_subsystems(root, added_mask);
1097         if (ret)
1098                 goto out_unlock;
1099 
1100         WARN_ON(rebind_subsystems(&cgrp_dfl_root, removed_mask));
1101 
1102         if (ctx->release_agent) {
1103                 spin_lock(&release_agent_path_lock);
1104                 strcpy(root->release_agent_path, ctx->release_agent);
1105                 spin_unlock(&release_agent_path_lock);
1106         }
1107 
1108         trace_cgroup_remount(root);
1109 
1110  out_unlock:
1111         mutex_unlock(&cgroup_mutex);
1112         return ret;
1113 }
1114 
1115 struct kernfs_syscall_ops cgroup1_kf_syscall_ops = {
1116         .rename                 = cgroup1_rename,
1117         .show_options           = cgroup1_show_options,
1118         .mkdir                  = cgroup_mkdir,
1119         .rmdir                  = cgroup_rmdir,
1120         .show_path              = cgroup_show_path,
1121 };
1122 
1123 /*
1124  * The guts of cgroup1 mount - find or create cgroup_root to use.
1125  * Called with cgroup_mutex held; returns 0 on success, -E... on
1126  * error and positive - in case when the candidate is busy dying.
1127  * On success it stashes a reference to cgroup_root into given
1128  * cgroup_fs_context; that reference is *NOT* counting towards the
1129  * cgroup_root refcount.
1130  */
1131 static int cgroup1_root_to_use(struct fs_context *fc)
1132 {
1133         struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
1134         struct cgroup_root *root;
1135         struct cgroup_subsys *ss;
1136         int i, ret;
1137 
1138         /* First find the desired set of subsystems */
1139         ret = check_cgroupfs_options(fc);
1140         if (ret)
1141                 return ret;
1142 
1143         /*
1144          * Destruction of cgroup root is asynchronous, so subsystems may
1145          * still be dying after the previous unmount.  Let's drain the
1146          * dying subsystems.  We just need to ensure that the ones
1147          * unmounted previously finish dying and don't care about new ones
1148          * starting.  Testing ref liveliness is good enough.
1149          */
1150         for_each_subsys(ss, i) {
1151                 if (!(ctx->subsys_mask & (1 << i)) ||
1152                     ss->root == &cgrp_dfl_root)
1153                         continue;
1154 
1155                 if (!percpu_ref_tryget_live(&ss->root->cgrp.self.refcnt))
1156                         return 1;       /* restart */
1157                 cgroup_put(&ss->root->cgrp);
1158         }
1159 
1160         for_each_root(root) {
1161                 bool name_match = false;
1162 
1163                 if (root == &cgrp_dfl_root)
1164                         continue;
1165 
1166                 /*
1167                  * If we asked for a name then it must match.  Also, if
1168                  * name matches but sybsys_mask doesn't, we should fail.
1169                  * Remember whether name matched.
1170                  */
1171                 if (ctx->name) {
1172                         if (strcmp(ctx->name, root->name))
1173                                 continue;
1174                         name_match = true;
1175                 }
1176 
1177                 /*
1178                  * If we asked for subsystems (or explicitly for no
1179                  * subsystems) then they must match.
1180                  */
1181                 if ((ctx->subsys_mask || ctx->none) &&
1182                     (ctx->subsys_mask != root->subsys_mask)) {
1183                         if (!name_match)
1184                                 continue;
1185                         return -EBUSY;
1186                 }
1187 
1188                 if (root->flags ^ ctx->flags)
1189                         pr_warn("new mount options do not match the existing superblock, will be ignored\n");
1190 
1191                 ctx->root = root;
1192                 return 0;
1193         }
1194 
1195         /*
1196          * No such thing, create a new one.  name= matching without subsys
1197          * specification is allowed for already existing hierarchies but we
1198          * can't create new one without subsys specification.
1199          */
1200         if (!ctx->subsys_mask && !ctx->none)
1201                 return cg_invalf(fc, "cgroup1: No subsys list or none specified");
1202 
1203         /* Hierarchies may only be created in the initial cgroup namespace. */
1204         if (ctx->ns != &init_cgroup_ns)
1205                 return -EPERM;
1206 
1207         root = kzalloc(sizeof(*root), GFP_KERNEL);
1208         if (!root)
1209                 return -ENOMEM;
1210 
1211         ctx->root = root;
1212         init_cgroup_root(ctx);
1213 
1214         ret = cgroup_setup_root(root, ctx->subsys_mask);
1215         if (ret)
1216                 cgroup_free_root(root);
1217         return ret;
1218 }
1219 
1220 int cgroup1_get_tree(struct fs_context *fc)
1221 {
1222         struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
1223         int ret;
1224 
1225         /* Check if the caller has permission to mount. */
1226         if (!ns_capable(ctx->ns->user_ns, CAP_SYS_ADMIN))
1227                 return -EPERM;
1228 
1229         cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
1230 
1231         ret = cgroup1_root_to_use(fc);
1232         if (!ret && !percpu_ref_tryget_live(&ctx->root->cgrp.self.refcnt))
1233                 ret = 1;        /* restart */
1234 
1235         mutex_unlock(&cgroup_mutex);
1236 
1237         if (!ret)
1238                 ret = cgroup_do_get_tree(fc);
1239 
1240         if (!ret && percpu_ref_is_dying(&ctx->root->cgrp.self.refcnt)) {
1241                 struct super_block *sb = fc->root->d_sb;
1242                 dput(fc->root);
1243                 deactivate_locked_super(sb);
1244                 ret = 1;
1245         }
1246 
1247         if (unlikely(ret > 0)) {
1248                 msleep(10);
1249                 return restart_syscall();
1250         }
1251         return ret;
1252 }
1253 
1254 static int __init cgroup1_wq_init(void)
1255 {
1256         /*
1257          * Used to destroy pidlists and separate to serve as flush domain.
1258          * Cap @max_active to 1 too.
1259          */
1260         cgroup_pidlist_destroy_wq = alloc_workqueue("cgroup_pidlist_destroy",
1261                                                     0, 1);
1262         BUG_ON(!cgroup_pidlist_destroy_wq);
1263         return 0;
1264 }
1265 core_initcall(cgroup1_wq_init);
1266 
1267 static int __init cgroup_no_v1(char *str)
1268 {
1269         struct cgroup_subsys *ss;
1270         char *token;
1271         int i;
1272 
1273         while ((token = strsep(&str, ",")) != NULL) {
1274                 if (!*token)
1275                         continue;
1276 
1277                 if (!strcmp(token, "all")) {
1278                         cgroup_no_v1_mask = U16_MAX;
1279                         continue;
1280                 }
1281 
1282                 if (!strcmp(token, "named")) {
1283                         cgroup_no_v1_named = true;
1284                         continue;
1285                 }
1286 
1287                 for_each_subsys(ss, i) {
1288                         if (strcmp(token, ss->name) &&
1289                             strcmp(token, ss->legacy_name))
1290                                 continue;
1291 
1292                         cgroup_no_v1_mask |= 1 << i;
1293                 }
1294         }
1295         return 1;
1296 }
1297 __setup("cgroup_no_v1=", cgroup_no_v1);
1298 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp