--- /dev/null
+#include "cgroup-internal.h"
+
+#include <linux/kmod.h>
+#include <linux/sort.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/delayacct.h>
+#include <linux/pid_namespace.h>
+#include <linux/cgroupstats.h>
+
+#include <trace/events/cgroup.h>
+
+/*
+ * pidlists linger the following amount before being destroyed. The goal
+ * is avoiding frequent destruction in the middle of consecutive read calls
+ * Expiring in the middle is a performance problem not a correctness one.
+ * 1 sec should be enough.
+ */
+#define CGROUP_PIDLIST_DESTROY_DELAY HZ
+
+/* Controllers blocked by the commandline in v1 */
+static u16 cgroup_no_v1_mask;
+
+/*
+ * pidlist destructions need to be flushed on cgroup destruction. Use a
+ * separate workqueue as flush domain.
+ */
+static struct workqueue_struct *cgroup_pidlist_destroy_wq;
+
+/*
+ * Protects cgroup_subsys->release_agent_path. Modifying it also requires
+ * cgroup_mutex. Reading requires either cgroup_mutex or this spinlock.
+ */
+DEFINE_SPINLOCK(release_agent_path_lock);
+
+bool cgroup_ssid_no_v1(int ssid)
+{
+ return cgroup_no_v1_mask & (1 << ssid);
+}
+
+/**
+ * cgroup_attach_task_all - attach task 'tsk' to all cgroups of task 'from'
+ * @from: attach to all cgroups of a given task
+ * @tsk: the task to be attached
+ */
+int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk)
+{
+ struct cgroup_root *root;
+ int retval = 0;
+
+ mutex_lock(&cgroup_mutex);
+ percpu_down_write(&cgroup_threadgroup_rwsem);
+ for_each_root(root) {
+ struct cgroup *from_cgrp;
+
+ if (root == &cgrp_dfl_root)
+ continue;
+
+ spin_lock_irq(&css_set_lock);
+ from_cgrp = task_cgroup_from_root(from, root);
+ spin_unlock_irq(&css_set_lock);
+
+ retval = cgroup_attach_task(from_cgrp, tsk, false);
+ if (retval)
+ break;
+ }
+ percpu_up_write(&cgroup_threadgroup_rwsem);
+ mutex_unlock(&cgroup_mutex);
+
+ return retval;
+}
+EXPORT_SYMBOL_GPL(cgroup_attach_task_all);
+
+/**
+ * cgroup_trasnsfer_tasks - move tasks from one cgroup to another
+ * @to: cgroup to which the tasks will be moved
+ * @from: cgroup in which the tasks currently reside
+ *
+ * Locking rules between cgroup_post_fork() and the migration path
+ * guarantee that, if a task is forking while being migrated, the new child
+ * is guaranteed to be either visible in the source cgroup after the
+ * parent's migration is complete or put into the target cgroup. No task
+ * can slip out of migration through forking.
+ */
+int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from)
+{
+ LIST_HEAD(preloaded_csets);
+ struct cgrp_cset_link *link;
+ struct css_task_iter it;
+ struct task_struct *task;
+ int ret;
+
+ if (cgroup_on_dfl(to))
+ return -EINVAL;
+
+ if (!cgroup_may_migrate_to(to))
+ return -EBUSY;
+
+ mutex_lock(&cgroup_mutex);
+
+ percpu_down_write(&cgroup_threadgroup_rwsem);
+
+ /* all tasks in @from are being moved, all csets are source */
+ spin_lock_irq(&css_set_lock);
+ list_for_each_entry(link, &from->cset_links, cset_link)
+ cgroup_migrate_add_src(link->cset, to, &preloaded_csets);
+ spin_unlock_irq(&css_set_lock);
+
+ ret = cgroup_migrate_prepare_dst(&preloaded_csets);
+ if (ret)
+ goto out_err;
+
+ /*
+ * Migrate tasks one-by-one until @from is empty. This fails iff
+ * ->can_attach() fails.
+ */
+ do {
+ css_task_iter_start(&from->self, &it);
+ task = css_task_iter_next(&it);
+ if (task)
+ get_task_struct(task);
+ css_task_iter_end(&it);
+
+ if (task) {
+ ret = cgroup_migrate(task, false, to->root);
+ if (!ret)
+ trace_cgroup_transfer_tasks(to, task, false);
+ put_task_struct(task);
+ }
+ } while (task && !ret);
+out_err:
+ cgroup_migrate_finish(&preloaded_csets);
+ percpu_up_write(&cgroup_threadgroup_rwsem);
+ mutex_unlock(&cgroup_mutex);
+ return ret;
+}
+
+/*
+ * Stuff for reading the 'tasks'/'procs' files.
+ *
+ * Reading this file can return large amounts of data if a cgroup has
+ * *lots* of attached tasks. So it may need several calls to read(),
+ * but we cannot guarantee that the information we produce is correct
+ * unless we produce it entirely atomically.
+ *
+ */
+
+/* which pidlist file are we talking about? */
+enum cgroup_filetype {
+ CGROUP_FILE_PROCS,
+ CGROUP_FILE_TASKS,
+};
+
+/*
+ * A pidlist is a list of pids that virtually represents the contents of one
+ * of the cgroup files ("procs" or "tasks"). We keep a list of such pidlists,
+ * a pair (one each for procs, tasks) for each pid namespace that's relevant
+ * to the cgroup.
+ */
+struct cgroup_pidlist {
+ /*
+ * used to find which pidlist is wanted. doesn't change as long as
+ * this particular list stays in the list.
+ */
+ struct { enum cgroup_filetype type; struct pid_namespace *ns; } key;
+ /* array of xids */
+ pid_t *list;
+ /* how many elements the above list has */
+ int length;
+ /* each of these stored in a list by its cgroup */
+ struct list_head links;
+ /* pointer to the cgroup we belong to, for list removal purposes */
+ struct cgroup *owner;
+ /* for delayed destruction */
+ struct delayed_work destroy_dwork;
+};
+
+/*
+ * The following two functions "fix" the issue where there are more pids
+ * than kmalloc will give memory for; in such cases, we use vmalloc/vfree.
+ * TODO: replace with a kernel-wide solution to this problem
+ */
+#define PIDLIST_TOO_LARGE(c) ((c) * sizeof(pid_t) > (PAGE_SIZE * 2))
+static void *pidlist_allocate(int count)
+{
+ if (PIDLIST_TOO_LARGE(count))
+ return vmalloc(count * sizeof(pid_t));
+ else
+ return kmalloc(count * sizeof(pid_t), GFP_KERNEL);
+}
+
+static void pidlist_free(void *p)
+{
+ kvfree(p);
+}
+
+/*
+ * Used to destroy all pidlists lingering waiting for destroy timer. None
+ * should be left afterwards.
+ */
+void cgroup_pidlist_destroy_all(struct cgroup *cgrp)
+{
+ struct cgroup_pidlist *l, *tmp_l;
+
+ mutex_lock(&cgrp->pidlist_mutex);
+ list_for_each_entry_safe(l, tmp_l, &cgrp->pidlists, links)
+ mod_delayed_work(cgroup_pidlist_destroy_wq, &l->destroy_dwork, 0);
+ mutex_unlock(&cgrp->pidlist_mutex);
+
+ flush_workqueue(cgroup_pidlist_destroy_wq);
+ BUG_ON(!list_empty(&cgrp->pidlists));
+}
+
+static void cgroup_pidlist_destroy_work_fn(struct work_struct *work)
+{
+ struct delayed_work *dwork = to_delayed_work(work);
+ struct cgroup_pidlist *l = container_of(dwork, struct cgroup_pidlist,
+ destroy_dwork);
+ struct cgroup_pidlist *tofree = NULL;
+
+ mutex_lock(&l->owner->pidlist_mutex);
+
+ /*
+ * Destroy iff we didn't get queued again. The state won't change
+ * as destroy_dwork can only be queued while locked.
+ */
+ if (!delayed_work_pending(dwork)) {
+ list_del(&l->links);
+ pidlist_free(l->list);
+ put_pid_ns(l->key.ns);
+ tofree = l;
+ }
+
+ mutex_unlock(&l->owner->pidlist_mutex);
+ kfree(tofree);
+}
+
+/*
+ * pidlist_uniq - given a kmalloc()ed list, strip out all duplicate entries
+ * Returns the number of unique elements.
+ */
+static int pidlist_uniq(pid_t *list, int length)
+{
+ int src, dest = 1;
+
+ /*
+ * we presume the 0th element is unique, so i starts at 1. trivial
+ * edge cases first; no work needs to be done for either
+ */
+ if (length == 0 || length == 1)
+ return length;
+ /* src and dest walk down the list; dest counts unique elements */
+ for (src = 1; src < length; src++) {
+ /* find next unique element */
+ while (list[src] == list[src-1]) {
+ src++;
+ if (src == length)
+ goto after;
+ }
+ /* dest always points to where the next unique element goes */
+ list[dest] = list[src];
+ dest++;
+ }
+after:
+ return dest;
+}
+
+/*
+ * The two pid files - task and cgroup.procs - guaranteed that the result
+ * is sorted, which forced this whole pidlist fiasco. As pid order is
+ * different per namespace, each namespace needs differently sorted list,
+ * making it impossible to use, for example, single rbtree of member tasks
+ * sorted by task pointer. As pidlists can be fairly large, allocating one
+ * per open file is dangerous, so cgroup had to implement shared pool of
+ * pidlists keyed by cgroup and namespace.
+ */
+static int cmppid(const void *a, const void *b)
+{
+ return *(pid_t *)a - *(pid_t *)b;
+}
+
+static struct cgroup_pidlist *cgroup_pidlist_find(struct cgroup *cgrp,
+ enum cgroup_filetype type)
+{
+ struct cgroup_pidlist *l;
+ /* don't need task_nsproxy() if we're looking at ourself */
+ struct pid_namespace *ns = task_active_pid_ns(current);
+
+ lockdep_assert_held(&cgrp->pidlist_mutex);
+
+ list_for_each_entry(l, &cgrp->pidlists, links)
+ if (l->key.type == type && l->key.ns == ns)
+ return l;
+ return NULL;
+}
+
+/*
+ * find the appropriate pidlist for our purpose (given procs vs tasks)
+ * returns with the lock on that pidlist already held, and takes care
+ * of the use count, or returns NULL with no locks held if we're out of
+ * memory.
+ */
+static struct cgroup_pidlist *cgroup_pidlist_find_create(struct cgroup *cgrp,
+ enum cgroup_filetype type)
+{
+ struct cgroup_pidlist *l;
+
+ lockdep_assert_held(&cgrp->pidlist_mutex);
+
+ l = cgroup_pidlist_find(cgrp, type);
+ if (l)
+ return l;
+
+ /* entry not found; create a new one */
+ l = kzalloc(sizeof(struct cgroup_pidlist), GFP_KERNEL);
+ if (!l)
+ return l;
+
+ INIT_DELAYED_WORK(&l->destroy_dwork, cgroup_pidlist_destroy_work_fn);
+ l->key.type = type;
+ /* don't need task_nsproxy() if we're looking at ourself */
+ l->key.ns = get_pid_ns(task_active_pid_ns(current));
+ l->owner = cgrp;
+ list_add(&l->links, &cgrp->pidlists);
+ return l;
+}
+
+/**
+ * cgroup_task_count - count the number of tasks in a cgroup.
+ * @cgrp: the cgroup in question
+ *
+ * Return the number of tasks in the cgroup. The returned number can be
+ * higher than the actual number of tasks due to css_set references from
+ * namespace roots and temporary usages.
+ */
+static int cgroup_task_count(const struct cgroup *cgrp)
+{
+ int count = 0;
+ struct cgrp_cset_link *link;
+
+ spin_lock_irq(&css_set_lock);
+ list_for_each_entry(link, &cgrp->cset_links, cset_link)
+ count += atomic_read(&link->cset->refcount);
+ spin_unlock_irq(&css_set_lock);
+ return count;
+}
+
+/*
+ * Load a cgroup's pidarray with either procs' tgids or tasks' pids
+ */
+static int pidlist_array_load(struct cgroup *cgrp, enum cgroup_filetype type,
+ struct cgroup_pidlist **lp)
+{
+ pid_t *array;
+ int length;
+ int pid, n = 0; /* used for populating the array */
+ struct css_task_iter it;
+ struct task_struct *tsk;
+ struct cgroup_pidlist *l;
+
+ lockdep_assert_held(&cgrp->pidlist_mutex);
+
+ /*
+ * If cgroup gets more users after we read count, we won't have
+ * enough space - tough. This race is indistinguishable to the
+ * caller from the case that the additional cgroup users didn't
+ * show up until sometime later on.
+ */
+ length = cgroup_task_count(cgrp);
+ array = pidlist_allocate(length);
+ if (!array)
+ return -ENOMEM;
+ /* now, populate the array */
+ css_task_iter_start(&cgrp->self, &it);
+ while ((tsk = css_task_iter_next(&it))) {
+ if (unlikely(n == length))
+ break;
+ /* get tgid or pid for procs or tasks file respectively */
+ if (type == CGROUP_FILE_PROCS)
+ pid = task_tgid_vnr(tsk);
+ else
+ pid = task_pid_vnr(tsk);
+ if (pid > 0) /* make sure to only use valid results */
+ array[n++] = pid;
+ }
+ css_task_iter_end(&it);
+ length = n;
+ /* now sort & (if procs) strip out duplicates */
+ sort(array, length, sizeof(pid_t), cmppid, NULL);
+ if (type == CGROUP_FILE_PROCS)
+ length = pidlist_uniq(array, length);
+
+ l = cgroup_pidlist_find_create(cgrp, type);
+ if (!l) {
+ pidlist_free(array);
+ return -ENOMEM;
+ }
+
+ /* store array, freeing old if necessary */
+ pidlist_free(l->list);
+ l->list = array;
+ l->length = length;
+ *lp = l;
+ return 0;
+}
+
+/*
+ * seq_file methods for the tasks/procs files. The seq_file position is the
+ * next pid to display; the seq_file iterator is a pointer to the pid
+ * in the cgroup->l->list array.
+ */
+
+static void *cgroup_pidlist_start(struct seq_file *s, loff_t *pos)
+{
+ /*
+ * Initially we receive a position value that corresponds to
+ * one more than the last pid shown (or 0 on the first call or
+ * after a seek to the start). Use a binary-search to find the
+ * next pid to display, if any
+ */
+ struct kernfs_open_file *of = s->private;
+ struct cgroup *cgrp = seq_css(s)->cgroup;
+ struct cgroup_pidlist *l;
+ enum cgroup_filetype type = seq_cft(s)->private;
+ int index = 0, pid = *pos;
+ int *iter, ret;
+
+ mutex_lock(&cgrp->pidlist_mutex);
+
+ /*
+ * !NULL @of->priv indicates that this isn't the first start()
+ * after open. If the matching pidlist is around, we can use that.
+ * Look for it. Note that @of->priv can't be used directly. It
+ * could already have been destroyed.
+ */
+ if (of->priv)
+ of->priv = cgroup_pidlist_find(cgrp, type);
+
+ /*
+ * Either this is the first start() after open or the matching
+ * pidlist has been destroyed inbetween. Create a new one.
+ */
+ if (!of->priv) {
+ ret = pidlist_array_load(cgrp, type,
+ (struct cgroup_pidlist **)&of->priv);
+ if (ret)
+ return ERR_PTR(ret);
+ }
+ l = of->priv;
+
+ if (pid) {
+ int end = l->length;
+
+ while (index < end) {
+ int mid = (index + end) / 2;
+ if (l->list[mid] == pid) {
+ index = mid;
+ break;
+ } else if (l->list[mid] <= pid)
+ index = mid + 1;
+ else
+ end = mid;
+ }
+ }
+ /* If we're off the end of the array, we're done */
+ if (index >= l->length)
+ return NULL;
+ /* Update the abstract position to be the actual pid that we found */
+ iter = l->list + index;
+ *pos = *iter;
+ return iter;
+}
+
+static void cgroup_pidlist_stop(struct seq_file *s, void *v)
+{
+ struct kernfs_open_file *of = s->private;
+ struct cgroup_pidlist *l = of->priv;
+
+ if (l)
+ mod_delayed_work(cgroup_pidlist_destroy_wq, &l->destroy_dwork,
+ CGROUP_PIDLIST_DESTROY_DELAY);
+ mutex_unlock(&seq_css(s)->cgroup->pidlist_mutex);
+}
+
+static void *cgroup_pidlist_next(struct seq_file *s, void *v, loff_t *pos)
+{
+ struct kernfs_open_file *of = s->private;
+ struct cgroup_pidlist *l = of->priv;
+ pid_t *p = v;
+ pid_t *end = l->list + l->length;
+ /*
+ * Advance to the next pid in the array. If this goes off the
+ * end, we're done
+ */
+ p++;
+ if (p >= end) {
+ return NULL;
+ } else {
+ *pos = *p;
+ return p;
+ }
+}
+
+static int cgroup_pidlist_show(struct seq_file *s, void *v)
+{
+ seq_printf(s, "%d\n", *(int *)v);
+
+ return 0;
+}
+
+static ssize_t cgroup_tasks_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ return __cgroup_procs_write(of, buf, nbytes, off, false);
+}
+
+static ssize_t cgroup_release_agent_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct cgroup *cgrp;
+
+ BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX);
+
+ cgrp = cgroup_kn_lock_live(of->kn, false);
+ if (!cgrp)
+ return -ENODEV;
+ spin_lock(&release_agent_path_lock);
+ strlcpy(cgrp->root->release_agent_path, strstrip(buf),
+ sizeof(cgrp->root->release_agent_path));
+ spin_unlock(&release_agent_path_lock);
+ cgroup_kn_unlock(of->kn);
+ return nbytes;
+}
+
+static int cgroup_release_agent_show(struct seq_file *seq, void *v)
+{
+ struct cgroup *cgrp = seq_css(seq)->cgroup;
+
+ spin_lock(&release_agent_path_lock);
+ seq_puts(seq, cgrp->root->release_agent_path);
+ spin_unlock(&release_agent_path_lock);
+ seq_putc(seq, '\n');
+ return 0;
+}
+
+static int cgroup_sane_behavior_show(struct seq_file *seq, void *v)
+{
+ seq_puts(seq, "0\n");
+ return 0;
+}
+
+static u64 cgroup_read_notify_on_release(struct cgroup_subsys_state *css,
+ struct cftype *cft)
+{
+ return notify_on_release(css->cgroup);
+}
+
+static int cgroup_write_notify_on_release(struct cgroup_subsys_state *css,
+ struct cftype *cft, u64 val)
+{
+ if (val)
+ set_bit(CGRP_NOTIFY_ON_RELEASE, &css->cgroup->flags);
+ else
+ clear_bit(CGRP_NOTIFY_ON_RELEASE, &css->cgroup->flags);
+ return 0;
+}
+
+static u64 cgroup_clone_children_read(struct cgroup_subsys_state *css,
+ struct cftype *cft)
+{
+ return test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
+}
+
+static int cgroup_clone_children_write(struct cgroup_subsys_state *css,
+ struct cftype *cft, u64 val)
+{
+ if (val)
+ set_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
+ else
+ clear_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
+ return 0;
+}
+
+/* cgroup core interface files for the legacy hierarchies */
+struct cftype cgroup_legacy_base_files[] = {
+ {
+ .name = "cgroup.procs",
+ .seq_start = cgroup_pidlist_start,
+ .seq_next = cgroup_pidlist_next,
+ .seq_stop = cgroup_pidlist_stop,
+ .seq_show = cgroup_pidlist_show,
+ .private = CGROUP_FILE_PROCS,
+ .write = cgroup_procs_write,
+ },
+ {
+ .name = "cgroup.clone_children",
+ .read_u64 = cgroup_clone_children_read,
+ .write_u64 = cgroup_clone_children_write,
+ },
+ {
+ .name = "cgroup.sane_behavior",
+ .flags = CFTYPE_ONLY_ON_ROOT,
+ .seq_show = cgroup_sane_behavior_show,
+ },
+ {
+ .name = "tasks",
+ .seq_start = cgroup_pidlist_start,
+ .seq_next = cgroup_pidlist_next,
+ .seq_stop = cgroup_pidlist_stop,
+ .seq_show = cgroup_pidlist_show,
+ .private = CGROUP_FILE_TASKS,
+ .write = cgroup_tasks_write,
+ },
+ {
+ .name = "notify_on_release",
+ .read_u64 = cgroup_read_notify_on_release,
+ .write_u64 = cgroup_write_notify_on_release,
+ },
+ {
+ .name = "release_agent",
+ .flags = CFTYPE_ONLY_ON_ROOT,
+ .seq_show = cgroup_release_agent_show,
+ .write = cgroup_release_agent_write,
+ .max_write_len = PATH_MAX - 1,
+ },
+ { } /* terminate */
+};
+
+/* Display information about each subsystem and each hierarchy */
+static int proc_cgroupstats_show(struct seq_file *m, void *v)
+{
+ struct cgroup_subsys *ss;
+ int i;
+
+ seq_puts(m, "#subsys_name\thierarchy\tnum_cgroups\tenabled\n");
+ /*
+ * ideally we don't want subsystems moving around while we do this.
+ * cgroup_mutex is also necessary to guarantee an atomic snapshot of
+ * subsys/hierarchy state.
+ */
+ mutex_lock(&cgroup_mutex);
+
+ for_each_subsys(ss, i)
+ seq_printf(m, "%s\t%d\t%d\t%d\n",
+ ss->legacy_name, ss->root->hierarchy_id,
+ atomic_read(&ss->root->nr_cgrps),
+ cgroup_ssid_enabled(i));
+
+ mutex_unlock(&cgroup_mutex);
+ return 0;
+}
+
+static int cgroupstats_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, proc_cgroupstats_show, NULL);
+}
+
+const struct file_operations proc_cgroupstats_operations = {
+ .open = cgroupstats_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+/**
+ * cgroupstats_build - build and fill cgroupstats
+ * @stats: cgroupstats to fill information into
+ * @dentry: A dentry entry belonging to the cgroup for which stats have
+ * been requested.
+ *
+ * Build and fill cgroupstats so that taskstats can export it to user
+ * space.
+ */
+int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
+{
+ struct kernfs_node *kn = kernfs_node_from_dentry(dentry);
+ struct cgroup *cgrp;
+ struct css_task_iter it;
+ struct task_struct *tsk;
+
+ /* it should be kernfs_node belonging to cgroupfs and is a directory */
+ if (dentry->d_sb->s_type != &cgroup_fs_type || !kn ||
+ kernfs_type(kn) != KERNFS_DIR)
+ return -EINVAL;
+
+ mutex_lock(&cgroup_mutex);
+
+ /*
+ * We aren't being called from kernfs and there's no guarantee on
+ * @kn->priv's validity. For this and css_tryget_online_from_dir(),
+ * @kn->priv is RCU safe. Let's do the RCU dancing.
+ */
+ rcu_read_lock();
+ cgrp = rcu_dereference(kn->priv);
+ if (!cgrp || cgroup_is_dead(cgrp)) {
+ rcu_read_unlock();
+ mutex_unlock(&cgroup_mutex);
+ return -ENOENT;
+ }
+ rcu_read_unlock();
+
+ css_task_iter_start(&cgrp->self, &it);
+ while ((tsk = css_task_iter_next(&it))) {
+ switch (tsk->state) {
+ case TASK_RUNNING:
+ stats->nr_running++;
+ break;
+ case TASK_INTERRUPTIBLE:
+ stats->nr_sleeping++;
+ break;
+ case TASK_UNINTERRUPTIBLE:
+ stats->nr_uninterruptible++;
+ break;
+ case TASK_STOPPED:
+ stats->nr_stopped++;
+ break;
+ default:
+ if (delayacct_is_task_waiting_on_io(tsk))
+ stats->nr_io_wait++;
+ break;
+ }
+ }
+ css_task_iter_end(&it);
+
+ mutex_unlock(&cgroup_mutex);
+ return 0;
+}
+
+void check_for_release(struct cgroup *cgrp)
+{
+ if (notify_on_release(cgrp) && !cgroup_is_populated(cgrp) &&
+ !css_has_online_children(&cgrp->self) && !cgroup_is_dead(cgrp))
+ schedule_work(&cgrp->release_agent_work);
+}
+
+/*
+ * Notify userspace when a cgroup is released, by running the
+ * configured release agent with the name of the cgroup (path
+ * relative to the root of cgroup file system) as the argument.
+ *
+ * Most likely, this user command will try to rmdir this cgroup.
+ *
+ * This races with the possibility that some other task will be
+ * attached to this cgroup before it is removed, or that some other
+ * user task will 'mkdir' a child cgroup of this cgroup. That's ok.
+ * The presumed 'rmdir' will fail quietly if this cgroup is no longer
+ * unused, and this cgroup will be reprieved from its death sentence,
+ * to continue to serve a useful existence. Next time it's released,
+ * we will get notified again, if it still has 'notify_on_release' set.
+ *
+ * The final arg to call_usermodehelper() is UMH_WAIT_EXEC, which
+ * means only wait until the task is successfully execve()'d. The
+ * separate release agent task is forked by call_usermodehelper(),
+ * then control in this thread returns here, without waiting for the
+ * release agent task. We don't bother to wait because the caller of
+ * this routine has no use for the exit status of the release agent
+ * task, so no sense holding our caller up for that.
+ */
+void cgroup_release_agent(struct work_struct *work)
+{
+ struct cgroup *cgrp =
+ container_of(work, struct cgroup, release_agent_work);
+ char *pathbuf = NULL, *agentbuf = NULL;
+ char *argv[3], *envp[3];
+ int ret;
+
+ mutex_lock(&cgroup_mutex);
+
+ pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
+ agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL);
+ if (!pathbuf || !agentbuf)
+ goto out;
+
+ spin_lock_irq(&css_set_lock);
+ ret = cgroup_path_ns_locked(cgrp, pathbuf, PATH_MAX, &init_cgroup_ns);
+ spin_unlock_irq(&css_set_lock);
+ if (ret < 0 || ret >= PATH_MAX)
+ goto out;
+
+ argv[0] = agentbuf;
+ argv[1] = pathbuf;
+ argv[2] = NULL;
+
+ /* minimal command environment */
+ envp[0] = "HOME=/";
+ envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
+ envp[2] = NULL;
+
+ mutex_unlock(&cgroup_mutex);
+ call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
+ goto out_free;
+out:
+ mutex_unlock(&cgroup_mutex);
+out_free:
+ kfree(agentbuf);
+ kfree(pathbuf);
+}
+
+/*
+ * cgroup_rename - Only allow simple rename of directories in place.
+ */
+int cgroup_rename(struct kernfs_node *kn, struct kernfs_node *new_parent,
+ const char *new_name_str)
+{
+ struct cgroup *cgrp = kn->priv;
+ int ret;
+
+ if (kernfs_type(kn) != KERNFS_DIR)
+ return -ENOTDIR;
+ if (kn->parent != new_parent)
+ return -EIO;
+
+ /*
+ * This isn't a proper migration and its usefulness is very
+ * limited. Disallow on the default hierarchy.
+ */
+ if (cgroup_on_dfl(cgrp))
+ return -EPERM;
+
+ /*
+ * We're gonna grab cgroup_mutex which nests outside kernfs
+ * active_ref. kernfs_rename() doesn't require active_ref
+ * protection. Break them before grabbing cgroup_mutex.
+ */
+ kernfs_break_active_protection(new_parent);
+ kernfs_break_active_protection(kn);
+
+ mutex_lock(&cgroup_mutex);
+
+ ret = kernfs_rename(kn, new_parent, new_name_str);
+ if (!ret)
+ trace_cgroup_rename(cgrp);
+
+ mutex_unlock(&cgroup_mutex);
+
+ kernfs_unbreak_active_protection(kn);
+ kernfs_unbreak_active_protection(new_parent);
+ return ret;
+}
+
+static int __init cgroup1_wq_init(void)
+{
+ /*
+ * Used to destroy pidlists and separate to serve as flush domain.
+ * Cap @max_active to 1 too.
+ */
+ cgroup_pidlist_destroy_wq = alloc_workqueue("cgroup_pidlist_destroy",
+ 0, 1);
+ BUG_ON(!cgroup_pidlist_destroy_wq);
+ return 0;
+}
+core_initcall(cgroup1_wq_init);
+
+static int __init cgroup_no_v1(char *str)
+{
+ struct cgroup_subsys *ss;
+ char *token;
+ int i;
+
+ while ((token = strsep(&str, ",")) != NULL) {
+ if (!*token)
+ continue;
+
+ if (!strcmp(token, "all")) {
+ cgroup_no_v1_mask = U16_MAX;
+ break;
+ }
+
+ for_each_subsys(ss, i) {
+ if (strcmp(token, ss->name) &&
+ strcmp(token, ss->legacy_name))
+ continue;
+
+ cgroup_no_v1_mask |= 1 << i;
+ }
+ }
+ return 1;
+}
+__setup("cgroup_no_v1=", cgroup_no_v1);
+
+
+#ifdef CONFIG_CGROUP_DEBUG
+static struct cgroup_subsys_state *
+debug_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+ struct cgroup_subsys_state *css = kzalloc(sizeof(*css), GFP_KERNEL);
+
+ if (!css)
+ return ERR_PTR(-ENOMEM);
+
+ return css;
+}
+
+static void debug_css_free(struct cgroup_subsys_state *css)
+{
+ kfree(css);
+}
+
+static u64 debug_taskcount_read(struct cgroup_subsys_state *css,
+ struct cftype *cft)
+{
+ return cgroup_task_count(css->cgroup);
+}
+
+static u64 current_css_set_read(struct cgroup_subsys_state *css,
+ struct cftype *cft)
+{
+ return (u64)(unsigned long)current->cgroups;
+}
+
+static u64 current_css_set_refcount_read(struct cgroup_subsys_state *css,
+ struct cftype *cft)
+{
+ u64 count;
+
+ rcu_read_lock();
+ count = atomic_read(&task_css_set(current)->refcount);
+ rcu_read_unlock();
+ return count;
+}
+
+static int current_css_set_cg_links_read(struct seq_file *seq, void *v)
+{
+ struct cgrp_cset_link *link;
+ struct css_set *cset;
+ char *name_buf;
+
+ name_buf = kmalloc(NAME_MAX + 1, GFP_KERNEL);
+ if (!name_buf)
+ return -ENOMEM;
+
+ spin_lock_irq(&css_set_lock);
+ rcu_read_lock();
+ cset = rcu_dereference(current->cgroups);
+ list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
+ struct cgroup *c = link->cgrp;
+
+ cgroup_name(c, name_buf, NAME_MAX + 1);
+ seq_printf(seq, "Root %d group %s\n",
+ c->root->hierarchy_id, name_buf);
+ }
+ rcu_read_unlock();
+ spin_unlock_irq(&css_set_lock);
+ kfree(name_buf);
+ return 0;
+}
+
+#define MAX_TASKS_SHOWN_PER_CSS 25
+static int cgroup_css_links_read(struct seq_file *seq, void *v)
+{
+ struct cgroup_subsys_state *css = seq_css(seq);
+ struct cgrp_cset_link *link;
+
+ spin_lock_irq(&css_set_lock);
+ list_for_each_entry(link, &css->cgroup->cset_links, cset_link) {
+ struct css_set *cset = link->cset;
+ struct task_struct *task;
+ int count = 0;
+
+ seq_printf(seq, "css_set %p\n", cset);
+
+ list_for_each_entry(task, &cset->tasks, cg_list) {
+ if (count++ > MAX_TASKS_SHOWN_PER_CSS)
+ goto overflow;
+ seq_printf(seq, " task %d\n", task_pid_vnr(task));
+ }
+
+ list_for_each_entry(task, &cset->mg_tasks, cg_list) {
+ if (count++ > MAX_TASKS_SHOWN_PER_CSS)
+ goto overflow;
+ seq_printf(seq, " task %d\n", task_pid_vnr(task));
+ }
+ continue;
+ overflow:
+ seq_puts(seq, " ...\n");
+ }
+ spin_unlock_irq(&css_set_lock);
+ return 0;
+}
+
+static u64 releasable_read(struct cgroup_subsys_state *css, struct cftype *cft)
+{
+ return (!cgroup_is_populated(css->cgroup) &&
+ !css_has_online_children(&css->cgroup->self));
+}
+
+static struct cftype debug_files[] = {
+ {
+ .name = "taskcount",
+ .read_u64 = debug_taskcount_read,
+ },
+
+ {
+ .name = "current_css_set",
+ .read_u64 = current_css_set_read,
+ },
+
+ {
+ .name = "current_css_set_refcount",
+ .read_u64 = current_css_set_refcount_read,
+ },
+
+ {
+ .name = "current_css_set_cg_links",
+ .seq_show = current_css_set_cg_links_read,
+ },
+
+ {
+ .name = "cgroup_css_links",
+ .seq_show = cgroup_css_links_read,
+ },
+
+ {
+ .name = "releasable",
+ .read_u64 = releasable_read,
+ },
+
+ { } /* terminate */
+};
+
+struct cgroup_subsys debug_cgrp_subsys = {
+ .css_alloc = debug_css_alloc,
+ .css_free = debug_css_free,
+ .legacy_cftypes = debug_files,
+};
+#endif /* CONFIG_CGROUP_DEBUG */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-#include <linux/cgroup.h>
+#include "cgroup-internal.h"
+
#include <linux/cred.h>
#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/init_task.h>
#include <linux/kernel.h>
-#include <linux/list.h>
#include <linux/magic.h>
-#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/mount.h>
#include <linux/pagemap.h>
#include <linux/spinlock.h>
#include <linux/percpu-rwsem.h>
#include <linux/string.h>
-#include <linux/sort.h>
-#include <linux/kmod.h>
-#include <linux/delayacct.h>
-#include <linux/cgroupstats.h>
#include <linux/hashtable.h>
-#include <linux/pid_namespace.h>
#include <linux/idr.h>
-#include <linux/vmalloc.h> /* TODO: replace with more sophisticated array */
#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/atomic.h>
#define CREATE_TRACE_POINTS
#include <trace/events/cgroup.h>
-/*
- * pidlists linger the following amount before being destroyed. The goal
- * is avoiding frequent destruction in the middle of consecutive read calls
- * Expiring in the middle is a performance problem not a correctness one.
- * 1 sec should be enough.
- */
-#define CGROUP_PIDLIST_DESTROY_DELAY HZ
-
#define CGROUP_FILE_NAME_MAX (MAX_CGROUP_TYPE_NAMELEN + \
MAX_CFTYPE_NAME + 2)
* These locks are exported if CONFIG_PROVE_RCU so that accessors in
* cgroup.h can use them for lockdep annotations.
*/
-#ifdef CONFIG_PROVE_RCU
DEFINE_MUTEX(cgroup_mutex);
DEFINE_SPINLOCK(css_set_lock);
+
+#ifdef CONFIG_PROVE_RCU
EXPORT_SYMBOL_GPL(cgroup_mutex);
EXPORT_SYMBOL_GPL(css_set_lock);
-#else
-static DEFINE_MUTEX(cgroup_mutex);
-static DEFINE_SPINLOCK(css_set_lock);
#endif
/*
*/
static DEFINE_SPINLOCK(cgroup_file_kn_lock);
-/*
- * Protects cgroup_subsys->release_agent_path. Modifying it also requires
- * cgroup_mutex. Reading requires either cgroup_mutex or this spinlock.
- */
-static DEFINE_SPINLOCK(release_agent_path_lock);
-
struct percpu_rw_semaphore cgroup_threadgroup_rwsem;
#define cgroup_assert_mutex_or_rcu_locked() \
*/
static struct workqueue_struct *cgroup_destroy_wq;
-/*
- * pidlist destructions need to be flushed on cgroup destruction. Use a
- * separate workqueue as flush domain.
- */
-static struct workqueue_struct *cgroup_pidlist_destroy_wq;
-
/* generate an array of cgroup subsystem pointers */
#define SUBSYS(_x) [_x ## _cgrp_id] = &_x ## _cgrp_subsys,
-static struct cgroup_subsys *cgroup_subsys[] = {
+struct cgroup_subsys *cgroup_subsys[] = {
#include <linux/cgroup_subsys.h>
};
#undef SUBSYS
*/
static bool cgrp_dfl_visible;
-/* Controllers blocked by the commandline in v1 */
-static u16 cgroup_no_v1_mask;
-
/* some controllers are not supported in the default hierarchy */
static u16 cgrp_dfl_inhibit_ss_mask;
static unsigned long cgrp_dfl_implicit_ss_mask;
/* The list of hierarchy roots */
-
-static LIST_HEAD(cgroup_roots);
+LIST_HEAD(cgroup_roots);
static int cgroup_root_count;
/* hierarchy ID allocation and mapping, protected by cgroup_mutex */
static struct file_system_type cgroup2_fs_type;
static struct cftype cgroup_dfl_base_files[];
-static struct cftype cgroup_legacy_base_files[];
-static int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
-static void cgroup_lock_and_drain_offline(struct cgroup *cgrp);
static int cgroup_apply_control(struct cgroup *cgrp);
static void cgroup_finalize_control(struct cgroup *cgrp, int ret);
static void css_task_iter_advance(struct css_task_iter *it);
* is fine for individual subsystems but unsuitable for cgroup core. This
* is slower static_key_enabled() based test indexed by @ssid.
*/
-static bool cgroup_ssid_enabled(int ssid)
+bool cgroup_ssid_enabled(int ssid)
{
if (CGROUP_SUBSYS_COUNT == 0)
return false;
return static_key_enabled(cgroup_subsys_enabled_key[ssid]);
}
-static bool cgroup_ssid_no_v1(int ssid)
-{
- return cgroup_no_v1_mask & (1 << ssid);
-}
-
/**
* cgroup_on_dfl - test whether a cgroup is on the default hierarchy
* @cgrp: the cgroup of interest
*
* - debug: disallowed on the default hierarchy.
*/
-static bool cgroup_on_dfl(const struct cgroup *cgrp)
+bool cgroup_on_dfl(const struct cgroup *cgrp)
{
return cgrp->root == &cgrp_dfl_root;
}
return css;
}
-/* convenient tests for these bits */
-static inline bool cgroup_is_dead(const struct cgroup *cgrp)
-{
- return !(cgrp->self.flags & CSS_ONLINE);
-}
-
static void cgroup_get(struct cgroup *cgrp)
{
WARN_ON_ONCE(cgroup_is_dead(cgrp));
}
EXPORT_SYMBOL_GPL(of_css);
-static int notify_on_release(const struct cgroup *cgrp)
-{
- return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
-}
-
/**
* for_each_css - iterate all css's of a cgroup
* @css: the iteration cursor
; \
else
-/**
- * for_each_subsys - iterate all enabled cgroup subsystems
- * @ss: the iteration cursor
- * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end
- */
-#define for_each_subsys(ss, ssid) \
- for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT && \
- (((ss) = cgroup_subsys[ssid]) || true); (ssid)++)
-
/**
* do_each_subsys_mask - filter for_each_subsys with a bitmask
* @ss: the iteration cursor
} \
} while (false)
-/* iterate across the hierarchies */
-#define for_each_root(root) \
- list_for_each_entry((root), &cgroup_roots, root_list)
-
/* iterate over child cgrps, lock should be held throughout iteration */
#define cgroup_for_each_live_child(child, cgrp) \
list_for_each_entry((child), &(cgrp)->self.children, self.sibling) \
; \
else
-static void cgroup_release_agent(struct work_struct *work);
-static void check_for_release(struct cgroup *cgrp);
-
-/*
- * A cgroup can be associated with multiple css_sets as different tasks may
- * belong to different cgroups on different hierarchies. In the other
- * direction, a css_set is naturally associated with multiple cgroups.
- * This M:N relationship is represented by the following link structure
- * which exists for each association and allows traversing the associations
- * from both sides.
- */
-struct cgrp_cset_link {
- /* the cgroup and css_set this link associates */
- struct cgroup *cgrp;
- struct css_set *cset;
-
- /* list of cgrp_cset_links anchored at cgrp->cset_links */
- struct list_head cset_link;
-
- /* list of cgrp_cset_links anchored at css_set->cgrp_links */
- struct list_head cgrp_link;
-};
-
/*
* The default css_set - used by init and its children prior to any
* hierarchies being mounted. It contains a pointer to the root state
return cset;
}
-static struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root)
+struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root)
{
struct cgroup *root_cgrp = kf_root->kn->priv;
* Return the cgroup for "task" from the given hierarchy. Must be
* called with cgroup_mutex and css_set_lock held.
*/
-static struct cgroup *task_cgroup_from_root(struct task_struct *task,
- struct cgroup_root *root)
+struct cgroup *task_cgroup_from_root(struct task_struct *task,
+ struct cgroup_root *root)
{
/*
* No need to lock the task - since we hold cgroup_mutex the
*/
static struct kernfs_syscall_ops cgroup_kf_syscall_ops;
-static const struct file_operations proc_cgroupstats_operations;
static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft,
char *buf)
* inaccessible any time. If the caller intends to continue to access the
* cgroup, it should pin it before invoking this function.
*/
-static void cgroup_kn_unlock(struct kernfs_node *kn)
+void cgroup_kn_unlock(struct kernfs_node *kn)
{
struct cgroup *cgrp;
* locking under kernfs active protection and allows all kernfs operations
* including self-removal.
*/
-static struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn,
- bool drain_offline)
+struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline)
{
struct cgroup *cgrp;
return ret;
}
-static int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask)
+int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask)
{
struct cgroup *dcgrp = &dst_root->cgrp;
struct cgroup_subsys *ss;
return len;
}
-static int cgroup_show_options(struct seq_file *seq,
- struct kernfs_root *kf_root)
+static int cgroup_show_options(struct seq_file *seq, struct kernfs_root *kf_root)
{
struct cgroup_root *root = cgroup_root_from_kf(kf_root);
struct cgroup_subsys *ss;
kernfs_kill_sb(sb);
}
-static struct file_system_type cgroup_fs_type = {
+struct file_system_type cgroup_fs_type = {
.name = "cgroup",
.mount = cgroup_mount,
.kill_sb = cgroup_kill_sb,
.fs_flags = FS_USERNS_MOUNT,
};
-static int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
- struct cgroup_namespace *ns)
+int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns)
{
struct cgroup *root = cset_cgroup_from_root(ns->root_cset, cgrp->root);
* zero for migration destination cgroups with tasks so that child cgroups
* don't compete against tasks.
*/
-static bool cgroup_may_migrate_to(struct cgroup *dst_cgrp)
+bool cgroup_may_migrate_to(struct cgroup *dst_cgrp)
{
return !cgroup_on_dfl(dst_cgrp) || !cgroup_parent(dst_cgrp) ||
!dst_cgrp->subtree_control;
* Undo cgroup_migrate_add_src() and cgroup_migrate_prepare_dst(). See
* those functions for details.
*/
-static void cgroup_migrate_finish(struct list_head *preloaded_csets)
+void cgroup_migrate_finish(struct list_head *preloaded_csets)
{
struct css_set *cset, *tmp_cset;
* into play and the preloaded css_sets are guaranteed to cover all
* migrations.
*/
-static void cgroup_migrate_add_src(struct css_set *src_cset,
- struct cgroup *dst_cgrp,
- struct list_head *preloaded_csets)
+void cgroup_migrate_add_src(struct css_set *src_cset,
+ struct cgroup *dst_cgrp,
+ struct list_head *preloaded_csets)
{
struct cgroup *src_cgrp;
* using cgroup_migrate(), cgroup_migrate_finish() must be called on
* @preloaded_csets.
*/
-static int cgroup_migrate_prepare_dst(struct list_head *preloaded_csets)
+int cgroup_migrate_prepare_dst(struct list_head *preloaded_csets)
{
LIST_HEAD(csets);
struct css_set *src_cset, *tmp_cset;
* decided for all targets by invoking group_migrate_prepare_dst() before
* actually starting migrating.
*/
-static int cgroup_migrate(struct task_struct *leader, bool threadgroup,
- struct cgroup_root *root)
+int cgroup_migrate(struct task_struct *leader, bool threadgroup,
+ struct cgroup_root *root)
{
struct cgroup_taskset tset = CGROUP_TASKSET_INIT(tset);
struct task_struct *task;
*
* Call holding cgroup_mutex and cgroup_threadgroup_rwsem.
*/
-static int cgroup_attach_task(struct cgroup *dst_cgrp,
- struct task_struct *leader, bool threadgroup)
+int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
+ bool threadgroup)
{
LIST_HEAD(preloaded_csets);
struct task_struct *task;
* function to attach either it or all tasks in its threadgroup. Will lock
* cgroup_mutex and threadgroup.
*/
-static ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf,
- size_t nbytes, loff_t off, bool threadgroup)
+ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf,
+ size_t nbytes, loff_t off, bool threadgroup)
{
struct task_struct *tsk;
struct cgroup_subsys *ss;
return ret ?: nbytes;
}
-/**
- * cgroup_attach_task_all - attach task 'tsk' to all cgroups of task 'from'
- * @from: attach to all cgroups of a given task
- * @tsk: the task to be attached
- */
-int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk)
-{
- struct cgroup_root *root;
- int retval = 0;
-
- mutex_lock(&cgroup_mutex);
- percpu_down_write(&cgroup_threadgroup_rwsem);
- for_each_root(root) {
- struct cgroup *from_cgrp;
-
- if (root == &cgrp_dfl_root)
- continue;
-
- spin_lock_irq(&css_set_lock);
- from_cgrp = task_cgroup_from_root(from, root);
- spin_unlock_irq(&css_set_lock);
-
- retval = cgroup_attach_task(from_cgrp, tsk, false);
- if (retval)
- break;
- }
- percpu_up_write(&cgroup_threadgroup_rwsem);
- mutex_unlock(&cgroup_mutex);
-
- return retval;
-}
-EXPORT_SYMBOL_GPL(cgroup_attach_task_all);
-
-static ssize_t cgroup_tasks_write(struct kernfs_open_file *of,
- char *buf, size_t nbytes, loff_t off)
-{
- return __cgroup_procs_write(of, buf, nbytes, off, false);
-}
-
-static ssize_t cgroup_procs_write(struct kernfs_open_file *of,
- char *buf, size_t nbytes, loff_t off)
+ssize_t cgroup_procs_write(struct kernfs_open_file *of, char *buf, size_t nbytes,
+ loff_t off)
{
return __cgroup_procs_write(of, buf, nbytes, off, true);
}
-static ssize_t cgroup_release_agent_write(struct kernfs_open_file *of,
- char *buf, size_t nbytes, loff_t off)
-{
- struct cgroup *cgrp;
-
- BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX);
-
- cgrp = cgroup_kn_lock_live(of->kn, false);
- if (!cgrp)
- return -ENODEV;
- spin_lock(&release_agent_path_lock);
- strlcpy(cgrp->root->release_agent_path, strstrip(buf),
- sizeof(cgrp->root->release_agent_path));
- spin_unlock(&release_agent_path_lock);
- cgroup_kn_unlock(of->kn);
- return nbytes;
-}
-
-static int cgroup_release_agent_show(struct seq_file *seq, void *v)
-{
- struct cgroup *cgrp = seq_css(seq)->cgroup;
-
- spin_lock(&release_agent_path_lock);
- seq_puts(seq, cgrp->root->release_agent_path);
- spin_unlock(&release_agent_path_lock);
- seq_putc(seq, '\n');
- return 0;
-}
-
-static int cgroup_sane_behavior_show(struct seq_file *seq, void *v)
-{
- seq_puts(seq, "0\n");
- return 0;
-}
-
static void cgroup_print_ss_mask(struct seq_file *seq, u16 ss_mask)
{
struct cgroup_subsys *ss;
* controller while the previous css is still around. This function grabs
* cgroup_mutex and drains the previous css instances of @cgrp's subtree.
*/
-static void cgroup_lock_and_drain_offline(struct cgroup *cgrp)
+void cgroup_lock_and_drain_offline(struct cgroup *cgrp)
__acquires(&cgroup_mutex)
{
struct cgroup *dsct;
.seq_show = cgroup_seqfile_show,
};
-/*
- * cgroup_rename - Only allow simple rename of directories in place.
- */
-static int cgroup_rename(struct kernfs_node *kn, struct kernfs_node *new_parent,
- const char *new_name_str)
-{
- struct cgroup *cgrp = kn->priv;
- int ret;
-
- if (kernfs_type(kn) != KERNFS_DIR)
- return -ENOTDIR;
- if (kn->parent != new_parent)
- return -EIO;
-
- /*
- * This isn't a proper migration and its usefulness is very
- * limited. Disallow on the default hierarchy.
- */
- if (cgroup_on_dfl(cgrp))
- return -EPERM;
-
- /*
- * We're gonna grab cgroup_mutex which nests outside kernfs
- * active_ref. kernfs_rename() doesn't require active_ref
- * protection. Break them before grabbing cgroup_mutex.
- */
- kernfs_break_active_protection(new_parent);
- kernfs_break_active_protection(kn);
-
- mutex_lock(&cgroup_mutex);
-
- ret = kernfs_rename(kn, new_parent, new_name_str);
- if (!ret)
- trace_cgroup_rename(cgrp);
-
- mutex_unlock(&cgroup_mutex);
-
- kernfs_unbreak_active_protection(kn);
- kernfs_unbreak_active_protection(new_parent);
- return ret;
-}
-
/* set uid and gid of cgroup dirs and files to that of the creator */
static int cgroup_kn_set_ugid(struct kernfs_node *kn)
{
spin_unlock_irqrestore(&cgroup_file_kn_lock, flags);
}
-/**
- * cgroup_task_count - count the number of tasks in a cgroup.
- * @cgrp: the cgroup in question
- *
- * Return the number of tasks in the cgroup. The returned number can be
- * higher than the actual number of tasks due to css_set references from
- * namespace roots and temporary usages.
- */
-static int cgroup_task_count(const struct cgroup *cgrp)
-{
- int count = 0;
- struct cgrp_cset_link *link;
-
- spin_lock_irq(&css_set_lock);
- list_for_each_entry(link, &cgrp->cset_links, cset_link)
- count += atomic_read(&link->cset->refcount);
- spin_unlock_irq(&css_set_lock);
- return count;
-}
-
/**
* css_next_child - find the next child of a given css
* @pos: the current position (%NULL to initiate traversal)
put_task_struct(it->cur_task);
}
-/**
- * cgroup_trasnsfer_tasks - move tasks from one cgroup to another
- * @to: cgroup to which the tasks will be moved
- * @from: cgroup in which the tasks currently reside
- *
- * Locking rules between cgroup_post_fork() and the migration path
- * guarantee that, if a task is forking while being migrated, the new child
- * is guaranteed to be either visible in the source cgroup after the
- * parent's migration is complete or put into the target cgroup. No task
- * can slip out of migration through forking.
- */
-int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from)
-{
- LIST_HEAD(preloaded_csets);
- struct cgrp_cset_link *link;
- struct css_task_iter it;
- struct task_struct *task;
- int ret;
-
- if (cgroup_on_dfl(to))
- return -EINVAL;
-
- if (!cgroup_may_migrate_to(to))
- return -EBUSY;
-
- mutex_lock(&cgroup_mutex);
-
- percpu_down_write(&cgroup_threadgroup_rwsem);
-
- /* all tasks in @from are being moved, all csets are source */
- spin_lock_irq(&css_set_lock);
- list_for_each_entry(link, &from->cset_links, cset_link)
- cgroup_migrate_add_src(link->cset, to, &preloaded_csets);
- spin_unlock_irq(&css_set_lock);
-
- ret = cgroup_migrate_prepare_dst(&preloaded_csets);
- if (ret)
- goto out_err;
-
- /*
- * Migrate tasks one-by-one until @from is empty. This fails iff
- * ->can_attach() fails.
- */
- do {
- css_task_iter_start(&from->self, &it);
- task = css_task_iter_next(&it);
- if (task)
- get_task_struct(task);
- css_task_iter_end(&it);
-
- if (task) {
- ret = cgroup_migrate(task, false, to->root);
- if (!ret)
- trace_cgroup_transfer_tasks(to, task, false);
- put_task_struct(task);
- }
- } while (task && !ret);
-out_err:
- cgroup_migrate_finish(&preloaded_csets);
- percpu_up_write(&cgroup_threadgroup_rwsem);
- mutex_unlock(&cgroup_mutex);
- return ret;
-}
-
static void cgroup_procs_release(struct kernfs_open_file *of)
{
if (of->priv) {
return 0;
}
-/*
- * Stuff for reading the 'tasks'/'procs' files.
- *
- * Reading this file can return large amounts of data if a cgroup has
- * *lots* of attached tasks. So it may need several calls to read(),
- * but we cannot guarantee that the information we produce is correct
- * unless we produce it entirely atomically.
- *
- */
-
-/* which pidlist file are we talking about? */
-enum cgroup_filetype {
- CGROUP_FILE_PROCS,
- CGROUP_FILE_TASKS,
-};
-
-/*
- * A pidlist is a list of pids that virtually represents the contents of one
- * of the cgroup files ("procs" or "tasks"). We keep a list of such pidlists,
- * a pair (one each for procs, tasks) for each pid namespace that's relevant
- * to the cgroup.
- */
-struct cgroup_pidlist {
- /*
- * used to find which pidlist is wanted. doesn't change as long as
- * this particular list stays in the list.
- */
- struct { enum cgroup_filetype type; struct pid_namespace *ns; } key;
- /* array of xids */
- pid_t *list;
- /* how many elements the above list has */
- int length;
- /* each of these stored in a list by its cgroup */
- struct list_head links;
- /* pointer to the cgroup we belong to, for list removal purposes */
- struct cgroup *owner;
- /* for delayed destruction */
- struct delayed_work destroy_dwork;
-};
-
-/*
- * The following two functions "fix" the issue where there are more pids
- * than kmalloc will give memory for; in such cases, we use vmalloc/vfree.
- * TODO: replace with a kernel-wide solution to this problem
- */
-#define PIDLIST_TOO_LARGE(c) ((c) * sizeof(pid_t) > (PAGE_SIZE * 2))
-static void *pidlist_allocate(int count)
-{
- if (PIDLIST_TOO_LARGE(count))
- return vmalloc(count * sizeof(pid_t));
- else
- return kmalloc(count * sizeof(pid_t), GFP_KERNEL);
-}
-
-static void pidlist_free(void *p)
-{
- kvfree(p);
-}
-
-/*
- * Used to destroy all pidlists lingering waiting for destroy timer. None
- * should be left afterwards.
- */
-static void cgroup_pidlist_destroy_all(struct cgroup *cgrp)
-{
- struct cgroup_pidlist *l, *tmp_l;
-
- mutex_lock(&cgrp->pidlist_mutex);
- list_for_each_entry_safe(l, tmp_l, &cgrp->pidlists, links)
- mod_delayed_work(cgroup_pidlist_destroy_wq, &l->destroy_dwork, 0);
- mutex_unlock(&cgrp->pidlist_mutex);
-
- flush_workqueue(cgroup_pidlist_destroy_wq);
- BUG_ON(!list_empty(&cgrp->pidlists));
-}
-
-static void cgroup_pidlist_destroy_work_fn(struct work_struct *work)
-{
- struct delayed_work *dwork = to_delayed_work(work);
- struct cgroup_pidlist *l = container_of(dwork, struct cgroup_pidlist,
- destroy_dwork);
- struct cgroup_pidlist *tofree = NULL;
-
- mutex_lock(&l->owner->pidlist_mutex);
-
- /*
- * Destroy iff we didn't get queued again. The state won't change
- * as destroy_dwork can only be queued while locked.
- */
- if (!delayed_work_pending(dwork)) {
- list_del(&l->links);
- pidlist_free(l->list);
- put_pid_ns(l->key.ns);
- tofree = l;
- }
-
- mutex_unlock(&l->owner->pidlist_mutex);
- kfree(tofree);
-}
-
-/*
- * pidlist_uniq - given a kmalloc()ed list, strip out all duplicate entries
- * Returns the number of unique elements.
- */
-static int pidlist_uniq(pid_t *list, int length)
-{
- int src, dest = 1;
-
- /*
- * we presume the 0th element is unique, so i starts at 1. trivial
- * edge cases first; no work needs to be done for either
- */
- if (length == 0 || length == 1)
- return length;
- /* src and dest walk down the list; dest counts unique elements */
- for (src = 1; src < length; src++) {
- /* find next unique element */
- while (list[src] == list[src-1]) {
- src++;
- if (src == length)
- goto after;
- }
- /* dest always points to where the next unique element goes */
- list[dest] = list[src];
- dest++;
- }
-after:
- return dest;
-}
-
-/*
- * The two pid files - task and cgroup.procs - guaranteed that the result
- * is sorted, which forced this whole pidlist fiasco. As pid order is
- * different per namespace, each namespace needs differently sorted list,
- * making it impossible to use, for example, single rbtree of member tasks
- * sorted by task pointer. As pidlists can be fairly large, allocating one
- * per open file is dangerous, so cgroup had to implement shared pool of
- * pidlists keyed by cgroup and namespace.
- */
-static int cmppid(const void *a, const void *b)
-{
- return *(pid_t *)a - *(pid_t *)b;
-}
-
-static struct cgroup_pidlist *cgroup_pidlist_find(struct cgroup *cgrp,
- enum cgroup_filetype type)
-{
- struct cgroup_pidlist *l;
- /* don't need task_nsproxy() if we're looking at ourself */
- struct pid_namespace *ns = task_active_pid_ns(current);
-
- lockdep_assert_held(&cgrp->pidlist_mutex);
-
- list_for_each_entry(l, &cgrp->pidlists, links)
- if (l->key.type == type && l->key.ns == ns)
- return l;
- return NULL;
-}
-
-/*
- * find the appropriate pidlist for our purpose (given procs vs tasks)
- * returns with the lock on that pidlist already held, and takes care
- * of the use count, or returns NULL with no locks held if we're out of
- * memory.
- */
-static struct cgroup_pidlist *cgroup_pidlist_find_create(struct cgroup *cgrp,
- enum cgroup_filetype type)
-{
- struct cgroup_pidlist *l;
-
- lockdep_assert_held(&cgrp->pidlist_mutex);
-
- l = cgroup_pidlist_find(cgrp, type);
- if (l)
- return l;
-
- /* entry not found; create a new one */
- l = kzalloc(sizeof(struct cgroup_pidlist), GFP_KERNEL);
- if (!l)
- return l;
-
- INIT_DELAYED_WORK(&l->destroy_dwork, cgroup_pidlist_destroy_work_fn);
- l->key.type = type;
- /* don't need task_nsproxy() if we're looking at ourself */
- l->key.ns = get_pid_ns(task_active_pid_ns(current));
- l->owner = cgrp;
- list_add(&l->links, &cgrp->pidlists);
- return l;
-}
-
-/*
- * Load a cgroup's pidarray with either procs' tgids or tasks' pids
- */
-static int pidlist_array_load(struct cgroup *cgrp, enum cgroup_filetype type,
- struct cgroup_pidlist **lp)
-{
- pid_t *array;
- int length;
- int pid, n = 0; /* used for populating the array */
- struct css_task_iter it;
- struct task_struct *tsk;
- struct cgroup_pidlist *l;
-
- lockdep_assert_held(&cgrp->pidlist_mutex);
-
- /*
- * If cgroup gets more users after we read count, we won't have
- * enough space - tough. This race is indistinguishable to the
- * caller from the case that the additional cgroup users didn't
- * show up until sometime later on.
- */
- length = cgroup_task_count(cgrp);
- array = pidlist_allocate(length);
- if (!array)
- return -ENOMEM;
- /* now, populate the array */
- css_task_iter_start(&cgrp->self, &it);
- while ((tsk = css_task_iter_next(&it))) {
- if (unlikely(n == length))
- break;
- /* get tgid or pid for procs or tasks file respectively */
- if (type == CGROUP_FILE_PROCS)
- pid = task_tgid_vnr(tsk);
- else
- pid = task_pid_vnr(tsk);
- if (pid > 0) /* make sure to only use valid results */
- array[n++] = pid;
- }
- css_task_iter_end(&it);
- length = n;
- /* now sort & (if procs) strip out duplicates */
- sort(array, length, sizeof(pid_t), cmppid, NULL);
- if (type == CGROUP_FILE_PROCS)
- length = pidlist_uniq(array, length);
-
- l = cgroup_pidlist_find_create(cgrp, type);
- if (!l) {
- pidlist_free(array);
- return -ENOMEM;
- }
-
- /* store array, freeing old if necessary */
- pidlist_free(l->list);
- l->list = array;
- l->length = length;
- *lp = l;
- return 0;
-}
-
-/**
- * cgroupstats_build - build and fill cgroupstats
- * @stats: cgroupstats to fill information into
- * @dentry: A dentry entry belonging to the cgroup for which stats have
- * been requested.
- *
- * Build and fill cgroupstats so that taskstats can export it to user
- * space.
- */
-int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
-{
- struct kernfs_node *kn = kernfs_node_from_dentry(dentry);
- struct cgroup *cgrp;
- struct css_task_iter it;
- struct task_struct *tsk;
-
- /* it should be kernfs_node belonging to cgroupfs and is a directory */
- if (dentry->d_sb->s_type != &cgroup_fs_type || !kn ||
- kernfs_type(kn) != KERNFS_DIR)
- return -EINVAL;
-
- mutex_lock(&cgroup_mutex);
-
- /*
- * We aren't being called from kernfs and there's no guarantee on
- * @kn->priv's validity. For this and css_tryget_online_from_dir(),
- * @kn->priv is RCU safe. Let's do the RCU dancing.
- */
- rcu_read_lock();
- cgrp = rcu_dereference(kn->priv);
- if (!cgrp || cgroup_is_dead(cgrp)) {
- rcu_read_unlock();
- mutex_unlock(&cgroup_mutex);
- return -ENOENT;
- }
- rcu_read_unlock();
-
- css_task_iter_start(&cgrp->self, &it);
- while ((tsk = css_task_iter_next(&it))) {
- switch (tsk->state) {
- case TASK_RUNNING:
- stats->nr_running++;
- break;
- case TASK_INTERRUPTIBLE:
- stats->nr_sleeping++;
- break;
- case TASK_UNINTERRUPTIBLE:
- stats->nr_uninterruptible++;
- break;
- case TASK_STOPPED:
- stats->nr_stopped++;
- break;
- default:
- if (delayacct_is_task_waiting_on_io(tsk))
- stats->nr_io_wait++;
- break;
- }
- }
- css_task_iter_end(&it);
-
- mutex_unlock(&cgroup_mutex);
- return 0;
-}
-
-
-/*
- * seq_file methods for the tasks/procs files. The seq_file position is the
- * next pid to display; the seq_file iterator is a pointer to the pid
- * in the cgroup->l->list array.
- */
-
-static void *cgroup_pidlist_start(struct seq_file *s, loff_t *pos)
-{
- /*
- * Initially we receive a position value that corresponds to
- * one more than the last pid shown (or 0 on the first call or
- * after a seek to the start). Use a binary-search to find the
- * next pid to display, if any
- */
- struct kernfs_open_file *of = s->private;
- struct cgroup *cgrp = seq_css(s)->cgroup;
- struct cgroup_pidlist *l;
- enum cgroup_filetype type = seq_cft(s)->private;
- int index = 0, pid = *pos;
- int *iter, ret;
-
- mutex_lock(&cgrp->pidlist_mutex);
-
- /*
- * !NULL @of->priv indicates that this isn't the first start()
- * after open. If the matching pidlist is around, we can use that.
- * Look for it. Note that @of->priv can't be used directly. It
- * could already have been destroyed.
- */
- if (of->priv)
- of->priv = cgroup_pidlist_find(cgrp, type);
-
- /*
- * Either this is the first start() after open or the matching
- * pidlist has been destroyed inbetween. Create a new one.
- */
- if (!of->priv) {
- ret = pidlist_array_load(cgrp, type,
- (struct cgroup_pidlist **)&of->priv);
- if (ret)
- return ERR_PTR(ret);
- }
- l = of->priv;
-
- if (pid) {
- int end = l->length;
-
- while (index < end) {
- int mid = (index + end) / 2;
- if (l->list[mid] == pid) {
- index = mid;
- break;
- } else if (l->list[mid] <= pid)
- index = mid + 1;
- else
- end = mid;
- }
- }
- /* If we're off the end of the array, we're done */
- if (index >= l->length)
- return NULL;
- /* Update the abstract position to be the actual pid that we found */
- iter = l->list + index;
- *pos = *iter;
- return iter;
-}
-
-static void cgroup_pidlist_stop(struct seq_file *s, void *v)
-{
- struct kernfs_open_file *of = s->private;
- struct cgroup_pidlist *l = of->priv;
-
- if (l)
- mod_delayed_work(cgroup_pidlist_destroy_wq, &l->destroy_dwork,
- CGROUP_PIDLIST_DESTROY_DELAY);
- mutex_unlock(&seq_css(s)->cgroup->pidlist_mutex);
-}
-
-static void *cgroup_pidlist_next(struct seq_file *s, void *v, loff_t *pos)
-{
- struct kernfs_open_file *of = s->private;
- struct cgroup_pidlist *l = of->priv;
- pid_t *p = v;
- pid_t *end = l->list + l->length;
- /*
- * Advance to the next pid in the array. If this goes off the
- * end, we're done
- */
- p++;
- if (p >= end) {
- return NULL;
- } else {
- *pos = *p;
- return p;
- }
-}
-
-static int cgroup_pidlist_show(struct seq_file *s, void *v)
-{
- seq_printf(s, "%d\n", *(int *)v);
-
- return 0;
-}
-
-static u64 cgroup_read_notify_on_release(struct cgroup_subsys_state *css,
- struct cftype *cft)
-{
- return notify_on_release(css->cgroup);
-}
-
-static int cgroup_write_notify_on_release(struct cgroup_subsys_state *css,
- struct cftype *cft, u64 val)
-{
- if (val)
- set_bit(CGRP_NOTIFY_ON_RELEASE, &css->cgroup->flags);
- else
- clear_bit(CGRP_NOTIFY_ON_RELEASE, &css->cgroup->flags);
- return 0;
-}
-
-static u64 cgroup_clone_children_read(struct cgroup_subsys_state *css,
- struct cftype *cft)
-{
- return test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
-}
-
-static int cgroup_clone_children_write(struct cgroup_subsys_state *css,
- struct cftype *cft, u64 val)
-{
- if (val)
- set_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
- else
- clear_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags);
- return 0;
-}
-
/* cgroup core interface files for the default hierarchy */
static struct cftype cgroup_dfl_base_files[] = {
{
{ } /* terminate */
};
-/* cgroup core interface files for the legacy hierarchies */
-static struct cftype cgroup_legacy_base_files[] = {
- {
- .name = "cgroup.procs",
- .seq_start = cgroup_pidlist_start,
- .seq_next = cgroup_pidlist_next,
- .seq_stop = cgroup_pidlist_stop,
- .seq_show = cgroup_pidlist_show,
- .private = CGROUP_FILE_PROCS,
- .write = cgroup_procs_write,
- },
- {
- .name = "cgroup.clone_children",
- .read_u64 = cgroup_clone_children_read,
- .write_u64 = cgroup_clone_children_write,
- },
- {
- .name = "cgroup.sane_behavior",
- .flags = CFTYPE_ONLY_ON_ROOT,
- .seq_show = cgroup_sane_behavior_show,
- },
- {
- .name = "tasks",
- .seq_start = cgroup_pidlist_start,
- .seq_next = cgroup_pidlist_next,
- .seq_stop = cgroup_pidlist_stop,
- .seq_show = cgroup_pidlist_show,
- .private = CGROUP_FILE_TASKS,
- .write = cgroup_tasks_write,
- },
- {
- .name = "notify_on_release",
- .read_u64 = cgroup_read_notify_on_release,
- .write_u64 = cgroup_write_notify_on_release,
- },
- {
- .name = "release_agent",
- .flags = CFTYPE_ONLY_ON_ROOT,
- .seq_show = cgroup_release_agent_show,
- .write = cgroup_release_agent_write,
- .max_write_len = PATH_MAX - 1,
- },
- { } /* terminate */
-};
-
/*
* css destruction is four-stage process.
*
*/
cgroup_destroy_wq = alloc_workqueue("cgroup_destroy", 0, 1);
BUG_ON(!cgroup_destroy_wq);
-
- /*
- * Used to destroy pidlists and separate to serve as flush domain.
- * Cap @max_active to 1 too.
- */
- cgroup_pidlist_destroy_wq = alloc_workqueue("cgroup_pidlist_destroy",
- 0, 1);
- BUG_ON(!cgroup_pidlist_destroy_wq);
-
return 0;
}
core_initcall(cgroup_wq_init);
return retval;
}
-/* Display information about each subsystem and each hierarchy */
-static int proc_cgroupstats_show(struct seq_file *m, void *v)
-{
- struct cgroup_subsys *ss;
- int i;
-
- seq_puts(m, "#subsys_name\thierarchy\tnum_cgroups\tenabled\n");
- /*
- * ideally we don't want subsystems moving around while we do this.
- * cgroup_mutex is also necessary to guarantee an atomic snapshot of
- * subsys/hierarchy state.
- */
- mutex_lock(&cgroup_mutex);
-
- for_each_subsys(ss, i)
- seq_printf(m, "%s\t%d\t%d\t%d\n",
- ss->legacy_name, ss->root->hierarchy_id,
- atomic_read(&ss->root->nr_cgrps),
- cgroup_ssid_enabled(i));
-
- mutex_unlock(&cgroup_mutex);
- return 0;
-}
-
-static int cgroupstats_open(struct inode *inode, struct file *file)
-{
- return single_open(file, proc_cgroupstats_show, NULL);
-}
-
-static const struct file_operations proc_cgroupstats_operations = {
- .open = cgroupstats_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = single_release,
-};
-
/**
* cgroup_fork - initialize cgroup related fields during copy_process()
* @child: pointer to task_struct of forking parent process.
put_css_set(cset);
}
-static void check_for_release(struct cgroup *cgrp)
-{
- if (notify_on_release(cgrp) && !cgroup_is_populated(cgrp) &&
- !css_has_online_children(&cgrp->self) && !cgroup_is_dead(cgrp))
- schedule_work(&cgrp->release_agent_work);
-}
-
-/*
- * Notify userspace when a cgroup is released, by running the
- * configured release agent with the name of the cgroup (path
- * relative to the root of cgroup file system) as the argument.
- *
- * Most likely, this user command will try to rmdir this cgroup.
- *
- * This races with the possibility that some other task will be
- * attached to this cgroup before it is removed, or that some other
- * user task will 'mkdir' a child cgroup of this cgroup. That's ok.
- * The presumed 'rmdir' will fail quietly if this cgroup is no longer
- * unused, and this cgroup will be reprieved from its death sentence,
- * to continue to serve a useful existence. Next time it's released,
- * we will get notified again, if it still has 'notify_on_release' set.
- *
- * The final arg to call_usermodehelper() is UMH_WAIT_EXEC, which
- * means only wait until the task is successfully execve()'d. The
- * separate release agent task is forked by call_usermodehelper(),
- * then control in this thread returns here, without waiting for the
- * release agent task. We don't bother to wait because the caller of
- * this routine has no use for the exit status of the release agent
- * task, so no sense holding our caller up for that.
- */
-static void cgroup_release_agent(struct work_struct *work)
-{
- struct cgroup *cgrp =
- container_of(work, struct cgroup, release_agent_work);
- char *pathbuf = NULL, *agentbuf = NULL;
- char *argv[3], *envp[3];
- int ret;
-
- mutex_lock(&cgroup_mutex);
-
- pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
- agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL);
- if (!pathbuf || !agentbuf)
- goto out;
-
- spin_lock_irq(&css_set_lock);
- ret = cgroup_path_ns_locked(cgrp, pathbuf, PATH_MAX, &init_cgroup_ns);
- spin_unlock_irq(&css_set_lock);
- if (ret < 0 || ret >= PATH_MAX)
- goto out;
-
- argv[0] = agentbuf;
- argv[1] = pathbuf;
- argv[2] = NULL;
-
- /* minimal command environment */
- envp[0] = "HOME=/";
- envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
- envp[2] = NULL;
-
- mutex_unlock(&cgroup_mutex);
- call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
- goto out_free;
-out:
- mutex_unlock(&cgroup_mutex);
-out_free:
- kfree(agentbuf);
- kfree(pathbuf);
-}
-
static int __init cgroup_disable(char *str)
{
struct cgroup_subsys *ss;
}
__setup("cgroup_disable=", cgroup_disable);
-static int __init cgroup_no_v1(char *str)
-{
- struct cgroup_subsys *ss;
- char *token;
- int i;
-
- while ((token = strsep(&str, ",")) != NULL) {
- if (!*token)
- continue;
-
- if (!strcmp(token, "all")) {
- cgroup_no_v1_mask = U16_MAX;
- break;
- }
-
- for_each_subsys(ss, i) {
- if (strcmp(token, ss->name) &&
- strcmp(token, ss->legacy_name))
- continue;
-
- cgroup_no_v1_mask |= 1 << i;
- }
- }
- return 1;
-}
-__setup("cgroup_no_v1=", cgroup_no_v1);
-
/**
* css_tryget_online_from_dir - get corresponding css from a cgroup dentry
* @dentry: directory dentry of interest
mutex_unlock(&cgroup_mutex);
}
#endif /* CONFIG_CGROUP_BPF */
-
-#ifdef CONFIG_CGROUP_DEBUG
-static struct cgroup_subsys_state *
-debug_css_alloc(struct cgroup_subsys_state *parent_css)
-{
- struct cgroup_subsys_state *css = kzalloc(sizeof(*css), GFP_KERNEL);
-
- if (!css)
- return ERR_PTR(-ENOMEM);
-
- return css;
-}
-
-static void debug_css_free(struct cgroup_subsys_state *css)
-{
- kfree(css);
-}
-
-static u64 debug_taskcount_read(struct cgroup_subsys_state *css,
- struct cftype *cft)
-{
- return cgroup_task_count(css->cgroup);
-}
-
-static u64 current_css_set_read(struct cgroup_subsys_state *css,
- struct cftype *cft)
-{
- return (u64)(unsigned long)current->cgroups;
-}
-
-static u64 current_css_set_refcount_read(struct cgroup_subsys_state *css,
- struct cftype *cft)
-{
- u64 count;
-
- rcu_read_lock();
- count = atomic_read(&task_css_set(current)->refcount);
- rcu_read_unlock();
- return count;
-}
-
-static int current_css_set_cg_links_read(struct seq_file *seq, void *v)
-{
- struct cgrp_cset_link *link;
- struct css_set *cset;
- char *name_buf;
-
- name_buf = kmalloc(NAME_MAX + 1, GFP_KERNEL);
- if (!name_buf)
- return -ENOMEM;
-
- spin_lock_irq(&css_set_lock);
- rcu_read_lock();
- cset = rcu_dereference(current->cgroups);
- list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
- struct cgroup *c = link->cgrp;
-
- cgroup_name(c, name_buf, NAME_MAX + 1);
- seq_printf(seq, "Root %d group %s\n",
- c->root->hierarchy_id, name_buf);
- }
- rcu_read_unlock();
- spin_unlock_irq(&css_set_lock);
- kfree(name_buf);
- return 0;
-}
-
-#define MAX_TASKS_SHOWN_PER_CSS 25
-static int cgroup_css_links_read(struct seq_file *seq, void *v)
-{
- struct cgroup_subsys_state *css = seq_css(seq);
- struct cgrp_cset_link *link;
-
- spin_lock_irq(&css_set_lock);
- list_for_each_entry(link, &css->cgroup->cset_links, cset_link) {
- struct css_set *cset = link->cset;
- struct task_struct *task;
- int count = 0;
-
- seq_printf(seq, "css_set %p\n", cset);
-
- list_for_each_entry(task, &cset->tasks, cg_list) {
- if (count++ > MAX_TASKS_SHOWN_PER_CSS)
- goto overflow;
- seq_printf(seq, " task %d\n", task_pid_vnr(task));
- }
-
- list_for_each_entry(task, &cset->mg_tasks, cg_list) {
- if (count++ > MAX_TASKS_SHOWN_PER_CSS)
- goto overflow;
- seq_printf(seq, " task %d\n", task_pid_vnr(task));
- }
- continue;
- overflow:
- seq_puts(seq, " ...\n");
- }
- spin_unlock_irq(&css_set_lock);
- return 0;
-}
-
-static u64 releasable_read(struct cgroup_subsys_state *css, struct cftype *cft)
-{
- return (!cgroup_is_populated(css->cgroup) &&
- !css_has_online_children(&css->cgroup->self));
-}
-
-static struct cftype debug_files[] = {
- {
- .name = "taskcount",
- .read_u64 = debug_taskcount_read,
- },
-
- {
- .name = "current_css_set",
- .read_u64 = current_css_set_read,
- },
-
- {
- .name = "current_css_set_refcount",
- .read_u64 = current_css_set_refcount_read,
- },
-
- {
- .name = "current_css_set_cg_links",
- .seq_show = current_css_set_cg_links_read,
- },
-
- {
- .name = "cgroup_css_links",
- .seq_show = cgroup_css_links_read,
- },
-
- {
- .name = "releasable",
- .read_u64 = releasable_read,
- },
-
- { } /* terminate */
-};
-
-struct cgroup_subsys debug_cgrp_subsys = {
- .css_alloc = debug_css_alloc,
- .css_free = debug_css_free,
- .legacy_cftypes = debug_files,
-};
-#endif /* CONFIG_CGROUP_DEBUG */
projects / mirror_ubuntu-artful-kernel.git / commitdiff