diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/Makefile | 5 | ||||
| -rw-r--r-- | kernel/cgroup/Makefile | 6 | ||||
| -rw-r--r-- | kernel/cgroup/cgroup-internal.h | 214 | ||||
| -rw-r--r-- | kernel/cgroup/cgroup-v1.c | 1395 | ||||
| -rw-r--r-- | kernel/cgroup/cgroup.c (renamed from kernel/cgroup.c) | 2081 | ||||
| -rw-r--r-- | kernel/cgroup/cpuset.c (renamed from kernel/cpuset.c) | 0 | ||||
| -rw-r--r-- | kernel/cgroup/freezer.c (renamed from kernel/cgroup_freezer.c) | 0 | ||||
| -rw-r--r-- | kernel/cgroup/namespace.c | 155 | ||||
| -rw-r--r-- | kernel/cgroup/pids.c (renamed from kernel/cgroup_pids.c) | 0 | ||||
| -rw-r--r-- | kernel/cgroup/rdma.c | 619 | ||||
| -rw-r--r-- | kernel/events/core.c | 6 |
11 files changed, 2641 insertions, 1840 deletions
diff --git a/kernel/Makefile b/kernel/Makefile index 12c679f769c6..b302b4731d16 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -64,10 +64,7 @@ obj-$(CONFIG_KEXEC) += kexec.o obj-$(CONFIG_KEXEC_FILE) += kexec_file.o obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o obj-$(CONFIG_COMPAT) += compat.o -obj-$(CONFIG_CGROUPS) += cgroup.o -obj-$(CONFIG_CGROUP_FREEZER) += cgroup_freezer.o -obj-$(CONFIG_CGROUP_PIDS) += cgroup_pids.o -obj-$(CONFIG_CPUSETS) += cpuset.o +obj-$(CONFIG_CGROUPS) += cgroup/ obj-$(CONFIG_UTS_NS) += utsname.o obj-$(CONFIG_USER_NS) += user_namespace.o obj-$(CONFIG_PID_NS) += pid_namespace.o diff --git a/kernel/cgroup/Makefile b/kernel/cgroup/Makefile new file mode 100644 index 000000000000..387348a40c64 --- /dev/null +++ b/kernel/cgroup/Makefile @@ -0,0 +1,6 @@ +obj-y := cgroup.o namespace.o cgroup-v1.o + +obj-$(CONFIG_CGROUP_FREEZER) += freezer.o +obj-$(CONFIG_CGROUP_PIDS) += pids.o +obj-$(CONFIG_CGROUP_RDMA) += rdma.o +obj-$(CONFIG_CPUSETS) += cpuset.o diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h new file mode 100644 index 000000000000..9203bfb05603 --- /dev/null +++ b/kernel/cgroup/cgroup-internal.h @@ -0,0 +1,214 @@ +#ifndef __CGROUP_INTERNAL_H +#define __CGROUP_INTERNAL_H + +#include <linux/cgroup.h> +#include <linux/kernfs.h> +#include <linux/workqueue.h> +#include <linux/list.h> + +/* + * 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; +}; + +/* used to track tasks and csets during migration */ +struct cgroup_taskset { + /* the src and dst cset list running through cset->mg_node */ + struct list_head src_csets; + struct list_head dst_csets; + + /* the subsys currently being processed */ + int ssid; + + /* + * Fields for cgroup_taskset_*() iteration. + * + * Before migration is committed, the target migration tasks are on + * ->mg_tasks of the csets on ->src_csets. After, on ->mg_tasks of + * the csets on ->dst_csets. ->csets point to either ->src_csets + * or ->dst_csets depending on whether migration is committed. + * + * ->cur_csets and ->cur_task point to the current task position + * during iteration. + */ + struct list_head *csets; + struct css_set *cur_cset; + struct task_struct *cur_task; +}; + +/* migration context also tracks preloading */ +struct cgroup_mgctx { + /* + * Preloaded source and destination csets. Used to guarantee + * atomic success or failure on actual migration. + */ + struct list_head preloaded_src_csets; + struct list_head preloaded_dst_csets; + + /* tasks and csets to migrate */ + struct cgroup_taskset tset; + + /* subsystems affected by migration */ + u16 ss_mask; +}; + +#define CGROUP_TASKSET_INIT(tset) \ +{ \ + .src_csets = LIST_HEAD_INIT(tset.src_csets), \ + .dst_csets = LIST_HEAD_INIT(tset.dst_csets), \ + .csets = &tset.src_csets, \ +} + +#define CGROUP_MGCTX_INIT(name) \ +{ \ + LIST_HEAD_INIT(name.preloaded_src_csets), \ + LIST_HEAD_INIT(name.preloaded_dst_csets), \ + CGROUP_TASKSET_INIT(name.tset), \ +} + +#define DEFINE_CGROUP_MGCTX(name) \ + struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name) + +struct cgroup_sb_opts { + u16 subsys_mask; + unsigned int flags; + char *release_agent; + bool cpuset_clone_children; + char *name; + /* User explicitly requested empty subsystem */ + bool none; +}; + +extern struct mutex cgroup_mutex; +extern spinlock_t css_set_lock; +extern struct cgroup_subsys *cgroup_subsys[]; +extern struct list_head cgroup_roots; +extern struct file_system_type cgroup_fs_type; + +/* iterate across the hierarchies */ +#define for_each_root(root) \ + list_for_each_entry((root), &cgroup_roots, root_list) + +/** + * 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)++) + +static inline bool cgroup_is_dead(const struct cgroup *cgrp) +{ + return !(cgrp->self.flags & CSS_ONLINE); +} + +static inline bool notify_on_release(const struct cgroup *cgrp) +{ + return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); +} + +void put_css_set_locked(struct css_set *cset); + +static inline void put_css_set(struct css_set *cset) +{ + unsigned long flags; + + /* + * Ensure that the refcount doesn't hit zero while any readers + * can see it. Similar to atomic_dec_and_lock(), but for an + * rwlock + */ + if (atomic_add_unless(&cset->refcount, -1, 1)) + return; + + spin_lock_irqsave(&css_set_lock, flags); + put_css_set_locked(cset); + spin_unlock_irqrestore(&css_set_lock, flags); +} + +/* + * refcounted get/put for css_set objects + */ +static inline void get_css_set(struct css_set *cset) +{ + atomic_inc(&cset->refcount); +} + +bool cgroup_ssid_enabled(int ssid); +bool cgroup_on_dfl(const struct cgroup *cgrp); + +struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root); +struct cgroup *task_cgroup_from_root(struct task_struct *task, + struct cgroup_root *root); +struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline); +void cgroup_kn_unlock(struct kernfs_node *kn); +int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen, + struct cgroup_namespace *ns); + +void cgroup_free_root(struct cgroup_root *root); +void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts); +int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask); +int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask); +struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags, + struct cgroup_root *root, unsigned long magic, + struct cgroup_namespace *ns); + +bool cgroup_may_migrate_to(struct cgroup *dst_cgrp); +void cgroup_migrate_finish(struct cgroup_mgctx *mgctx); +void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp, + struct cgroup_mgctx *mgctx); +int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx); +int cgroup_migrate(struct task_struct *leader, bool threadgroup, + struct cgroup_mgctx *mgctx); + +int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader, + bool threadgroup); +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); + +void cgroup_lock_and_drain_offline(struct cgroup *cgrp); + +int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode); +int cgroup_rmdir(struct kernfs_node *kn); +int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node, + struct kernfs_root *kf_root); + +/* + * namespace.c + */ +extern const struct proc_ns_operations cgroupns_operations; + +/* + * cgroup-v1.c + */ +extern struct cftype cgroup1_base_files[]; +extern const struct file_operations proc_cgroupstats_operations; +extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops; + +bool cgroup1_ssid_disabled(int ssid); +void cgroup1_pidlist_destroy_all(struct cgroup *cgrp); +void cgroup1_release_agent(struct work_struct *work); +void cgroup1_check_for_release(struct cgroup *cgrp); +struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags, + void *data, unsigned long magic, + struct cgroup_namespace *ns); + +#endif /* __CGROUP_INTERNAL_H */ diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c new file mode 100644 index 000000000000..fc34bcf2329f --- /dev/null +++ b/kernel/cgroup/cgroup-v1.c @@ -0,0 +1,1395 @@ +#include "cgroup-internal.h" + +#include <linux/ctype.h> +#include <linux/kmod.h> +#include <linux/sort.h> +#include <linux/delay.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. + */ +static DEFINE_SPINLOCK(release_agent_path_lock); + +bool cgroup1_ssid_disabled(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) +{ + DEFINE_CGROUP_MGCTX(mgctx); + 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, &mgctx); + spin_unlock_irq(&css_set_lock); + + ret = cgroup_migrate_prepare_dst(&mgctx); + 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, &mgctx); + if (!ret) + trace_cgroup_transfer_tasks(to, task, false); + put_task_struct(task); + } + } while (task && !ret); +out_err: + cgroup_migrate_finish(&mgctx); + 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 cgroup1_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 cgroup1_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(*(void __rcu __force **)&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 cgroup1_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 cgroup1_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. + */ +static int cgroup1_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; + + /* + * 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 cgroup1_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; + int ssid; + + for_each_subsys(ss, ssid) + if (root->subsys_mask & (1 << ssid)) + seq_show_option(seq, ss->legacy_name, NULL); + if (root->flags & CGRP_ROOT_NOPREFIX) + seq_puts(seq, ",noprefix"); + if (root->flags & CGRP_ROOT_XATTR) + seq_puts(seq, ",xattr"); + + spin_lock(&release_agent_path_lock); + if (strlen(root->release_agent_path)) + seq_show_option(seq, "release_agent", + root->release_agent_path); + spin_unlock(&release_agent_path_lock); + + if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags)) + seq_puts(seq, ",clone_children"); + if (strlen(root->name)) + seq_show_option(seq, "name", root->name); + return 0; +} + +static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) +{ + char *token, *o = data; + bool all_ss = false, one_ss = false; + u16 mask = U16_MAX; + struct cgroup_subsys *ss; + int nr_opts = 0; + int i; + +#ifdef CONFIG_CPUSETS + mask = ~((u16)1 << cpuset_cgrp_id); +#endif + + memset(opts, 0, sizeof(*opts)); + + while ((token = strsep(&o, ",")) != NULL) { + nr_opts++; + + if (!*token) + return -EINVAL; + if (!strcmp(token, "none")) { + /* Explicitly have no subsystems */ + opts->none = true; + continue; + } + if (!strcmp(token, "all")) { + /* Mutually exclusive option 'all' + subsystem name */ + if (one_ss) + return -EINVAL; + all_ss = true; + continue; + } + if (!strcmp(token, "noprefix")) { + opts->flags |= CGRP_ROOT_NOPREFIX; + continue; + } + if (!strcmp(token, "clone_children")) { + opts->cpuset_clone_children = true; + continue; + } + if (!strcmp(token, "xattr")) { + opts->flags |= CGRP_ROOT_XATTR; + continue; + } + if (!strncmp(token, "release_agent=", 14)) { + /* Specifying two release agents is forbidden */ + if (opts->release_agent) + return -EINVAL; + opts->release_agent = + kstrndup(token + 14, PATH_MAX - 1, GFP_KERNEL); + if (!opts->release_agent) + return -ENOMEM; + continue; + } + if (!strncmp(token, "name=", 5)) { + const char *name = token + 5; + /* Can't specify an empty name */ + if (!strlen(name)) + return -EINVAL; + /* Must match [\w.-]+ */ + for (i = 0; i < strlen(name); i++) { + char c = name[i]; + if (isalnum(c)) + continue; + if ((c == '.') || (c == '-') || (c == '_')) + continue; + return -EINVAL; + } + /* Specifying two names is forbidden */ + if (opts->name) + return -EINVAL; + opts->name = kstrndup(name, + MAX_CGROUP_ROOT_NAMELEN - 1, + GFP_KERNEL); + if (!opts->name) + return -ENOMEM; + + continue; + } + + for_each_subsys(ss, i) { + if (strcmp(token, ss->legacy_name)) + continue; + if (!cgroup_ssid_enabled(i)) + continue; + if (cgroup1_ssid_disabled(i)) + continue; + + /* Mutually exclusive option 'all' + subsystem name */ + if (all_ss) + return -EINVAL; + opts->subsys_mask |= (1 << i); + one_ss = true; + + break; + } + if (i == CGROUP_SUBSYS_COUNT) + return -ENOENT; + } + + /* + * If the 'all' option was specified select all the subsystems, + * otherwise if 'none', 'name=' and a subsystem name options were + * not specified, let's default to 'all' + */ + if (all_ss || (!one_ss && !opts->none && !opts->name)) + for_each_subsys(ss, i) + if (cgroup_ssid_enabled(i) && !cgroup1_ssid_disabled(i)) + opts->subsys_mask |= (1 << i); + + /* + * We either have to specify by name or by subsystems. (So all + * empty hierarchies must have a name). + */ + if (!opts->subsys_mask && !opts->name) + return -EINVAL; + + /* + * Option noprefix was introduced just for backward compatibility + * with the old cpuset, so we allow noprefix only if mounting just + * the cpuset subsystem. + */ + if ((opts->flags & CGRP_ROOT_NOPREFIX) && (opts->subsys_mask & mask)) + return -EINVAL; + + /* Can't specify "none" and some subsystems */ + if (opts->subsys_mask && opts->none) + return -EINVAL; + + return 0; +} + +static int cgroup1_remount(struct kernfs_root *kf_root, int *flags, char *data) +{ + int ret = 0; + struct cgroup_root *root = cgroup_root_from_kf(kf_root); + struct cgroup_sb_opts opts; + u16 added_mask, removed_mask; + + cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp); + + /* See what subsystems are wanted */ + ret = parse_cgroupfs_options(data, &opts); + if (ret) + goto out_unlock; + + if (opts.subsys_mask != root->subsys_mask || opts.release_agent) + pr_warn("option changes via remount are deprecated (pid=%d comm=%s)\n", + task_tgid_nr(current), current->comm); + + added_mask = opts.subsys_mask & ~root->subsys_mask; + removed_mask = root->subsys_mask & ~opts.subsys_mask; + + /* Don't allow flags or name to change at remount */ + if ((opts.flags ^ root->flags) || + (opts.name && strcmp(opts.name, root->name))) { + pr_err("option or name mismatch, new: 0x%x \"%s\", old: 0x%x \"%s\"\n", + opts.flags, opts.name ?: "", root->flags, root->name); + ret = -EINVAL; + goto out_unlock; + } + + /* remounting is not allowed for populated hierarchies */ + if (!list_empty(&root->cgrp.self.children)) { + ret = -EBUSY; + goto out_unlock; + } + + ret = rebind_subsystems(root, added_mask); + if (ret) + goto out_unlock; + + WARN_ON(rebind_subsystems(&cgrp_dfl_root, removed_mask)); + + if (opts.release_agent) { + spin_lock(&release_agent_path_lock); + strcpy(root->release_agent_path, opts.release_agent); + spin_unlock(&release_agent_path_lock); + } + + trace_cgroup_remount(root); + + out_unlock: + kfree(opts.release_agent); + kfree(opts.name); + mutex_unlock(&cgroup_mutex); + return ret; +} + +struct kernfs_syscall_ops cgroup1_kf_syscall_ops = { + .rename = cgroup1_rename, + .show_options = cgroup1_show_options, + .remount_fs = cgroup1_remount, + .mkdir = cgroup_mkdir, + .rmdir = cgroup_rmdir, + .show_path = cgroup_show_path, +}; + +struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags, + void *data, unsigned long magic, + struct cgroup_namespace *ns) +{ + struct super_block *pinned_sb = NULL; + struct cgroup_sb_opts opts; + struct cgroup_root *root; + struct cgroup_subsys *ss; + struct dentry *dentry; + int i, ret; + + cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp); + + /* First find the desired set of subsystems */ + ret = parse_cgroupfs_options(data, &opts); + if (ret) + goto out_unlock; + + /* + * Destruction of cgroup root is asynchronous, so subsystems may + * still be dying after the previous unmount. Let's drain the + * dying subsystems. We just need to ensure that the ones + * unmounted previously finish dying and don't care about new ones + * starting. Testing ref liveliness is good enough. + */ + for_each_subsys(ss, i) { + if (!(opts.subsys_mask & (1 << i)) || + ss->root == &cgrp_dfl_root) + continue; + + if (!percpu_ref_tryget_live(&ss->root->cgrp.self.refcnt)) { + mutex_unlock(&cgroup_mutex); + msleep(10); + ret = restart_syscall(); + goto out_free; + } + cgroup_put(&ss->root->cgrp); + } + + for_each_root(root) { + bool name_match = false; + + if (root == &cgrp_dfl_root) + continue; + + /* + * If we asked for a name then it must match. Also, if + * name matches but sybsys_mask doesn't, we should fail. + * Remember whether name matched. + */ + if (opts.name) { + if (strcmp(opts.name, root->name)) + continue; + name_match = true; + } + + /* + * If we asked for subsystems (or explicitly for no + * subsystems) then they must match. + */ + if ((opts.subsys_mask || opts.none) && + (opts.subsys_mask != root->subsys_mask)) { + if (!name_match) + continue; + ret = -EBUSY; + goto out_unlock; + } + + if (root->flags ^ opts.flags) + pr_warn("new mount options do not match the existing superblock, will be ignored\n"); + + /* + * We want to reuse @root whose lifetime is governed by its + * ->cgrp. Let's check whether @root is alive and keep it + * that way. As cgroup_kill_sb() can happen anytime, we + * want to block it by pinning the sb so that @root doesn't + * get killed before mount is complete. + * + * With the sb pinned, tryget_live can reliably indicate + * whether @root can be reused. If it's being killed, + * drain it. We can use wait_queue for the wait but this + * path is super cold. Let's just sleep a bit and retry. + */ + pinned_sb = kernfs_pin_sb(root->kf_root, NULL); + if (IS_ERR(pinned_sb) || + !percpu_ref_tryget_live(&root->cgrp.self.refcnt)) { + mutex_unlock(&cgroup_mutex); + if (!IS_ERR_OR_NULL(pinned_sb)) + deactivate_super(pinned_sb); + msleep(10); + ret = restart_syscall(); + goto out_free; + } + + ret = 0; + goto out_unlock; + } + + /* + * No such thing, create a new one. name= matching without subsys + * specification is allowed for already existing hierarchies but we + * can't create new one without subsys specification. + */ + if (!opts.subsys_mask && !opts.none) { + ret = -EINVAL; + goto out_unlock; + } + + /* Hierarchies may only be created in the initial cgroup namespace. */ + if (ns != &init_cgroup_ns) { + ret = -EPERM; + goto out_unlock; + } + + root = kzalloc(sizeof(*root), GFP_KERNEL); + if (!root) { + ret = -ENOMEM; + goto out_unlock; + } + + init_cgroup_root(root, &opts); + + ret = cgroup_setup_root(root, opts.subsys_mask); + if (ret) + cgroup_free_root(root); + +out_unlock: + mutex_unlock(&cgroup_mutex); +out_free: + kfree(opts.release_agent); + kfree(opts.name); + + if (ret) + return ERR_PTR(ret); + + dentry = cgroup_do_mount(&cgroup_fs_type, flags, root, + CGROUP_SUPER_MAGIC, ns); + + /* + * If @pinned_sb, we're reusing an existing root and holding an + * extra ref on its sb. Mount is complete. Put the extra ref. + */ + if (pinned_sb) + deactivate_super(pinned_sb); + + return dentry; +} + +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 */ diff --git a/kernel/cgroup.c b/kernel/cgroup/cgroup.c index 53bbca7c4859..e8f87bf9840c 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -28,15 +28,13 @@ #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> @@ -47,16 +45,9 @@ #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> #include <linux/cpuset.h> #include <linux/proc_ns.h> @@ -67,14 +58,6 @@ #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) @@ -88,14 +71,12 @@ * 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 /* @@ -110,12 +91,6 @@ static DEFINE_SPINLOCK(cgroup_idr_lock); */ 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() \ @@ -131,15 +106,9 @@ struct percpu_rw_semaphore cgroup_threadgroup_rwsem; */ 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 @@ -186,18 +155,14 @@ EXPORT_SYMBOL_GPL(cgrp_dfl_root); */ 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; /* some controllers are implicitly enabled on the default hierarchy */ -static unsigned long cgrp_dfl_implicit_ss_mask; +static u16 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 */ @@ -213,13 +178,13 @@ static DEFINE_IDR(cgroup_hierarchy_idr); static u64 css_serial_nr_next = 1; /* - * These bitmask flags indicate whether tasks in the fork and exit paths have - * fork/exit handlers to call. This avoids us having to do extra work in the - * fork/exit path to check which subsystems have fork/exit callbacks. + * These bitmasks identify subsystems with specific features to avoid + * having to do iterative checks repeatedly. */ static u16 have_fork_callback __read_mostly; static u16 have_exit_callback __read_mostly; static u16 have_free_callback __read_mostly; +static u16 have_canfork_callback __read_mostly; /* cgroup namespace for init task */ struct cgroup_namespace init_cgroup_ns = { @@ -230,15 +195,9 @@ struct cgroup_namespace init_cgroup_ns = { .root_cset = &init_css_set, }; -/* Ditto for the can_fork callback. */ -static u16 have_canfork_callback __read_mostly; - static struct file_system_type cgroup2_fs_type; -static struct cftype cgroup_dfl_base_files[]; -static struct cftype cgroup_legacy_base_files[]; +static struct cftype cgroup_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); @@ -259,7 +218,7 @@ static int cgroup_addrm_files(struct cgroup_subsys_state *css, * 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; @@ -267,11 +226,6 @@ static bool cgroup_ssid_enabled(int ssid) 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 @@ -325,7 +279,7 @@ static bool cgroup_ssid_no_v1(int ssid) * * - 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; } @@ -481,12 +435,6 @@ out_unlock: 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)); @@ -518,11 +466,6 @@ struct cgroup_subsys_state *of_css(struct kernfs_open_file *of) } 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 @@ -553,15 +496,6 @@ static int notify_on_release(const struct cgroup *cgrp) 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 * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end @@ -585,10 +519,6 @@ static int notify_on_release(const struct cgroup *cgrp) } \ } 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) \ @@ -615,29 +545,6 @@ static int notify_on_release(const struct cgroup *cgrp) ; \ 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 @@ -647,12 +554,12 @@ struct cgrp_cset_link { */ struct css_set init_css_set = { .refcount = ATOMIC_INIT(1), - .cgrp_links = LIST_HEAD_INIT(init_css_set.cgrp_links), .tasks = LIST_HEAD_INIT(init_css_set.tasks), .mg_tasks = LIST_HEAD_INIT(init_css_set.mg_tasks), + .task_iters = LIST_HEAD_INIT(init_css_set.task_iters), + .cgrp_links = LIST_HEAD_INIT(init_css_set.cgrp_links), .mg_preload_node = LIST_HEAD_INIT(init_css_set.mg_preload_node), .mg_node = LIST_HEAD_INIT(init_css_set.mg_node), - .task_iters = LIST_HEAD_INIT(init_css_set.task_iters), }; static int css_set_count = 1; /* 1 for init_css_set */ @@ -699,7 +606,7 @@ static void cgroup_update_populated(struct cgroup *cgrp, bool populated) if (!trigger) break; - check_for_release(cgrp); + cgroup1_check_for_release(cgrp); cgroup_file_notify(&cgrp->events_file); cgrp = cgroup_parent(cgrp); @@ -808,7 +715,7 @@ static unsigned long css_set_hash(struct cgroup_subsys_state *css[]) return key; } -static void put_css_set_locked(struct css_set *cset) +void put_css_set_locked(struct css_set *cset) { struct cgrp_cset_link *link, *tmp_link; struct cgroup_subsys *ss; @@ -838,31 +745,6 @@ static void put_css_set_locked(struct css_set *cset) kfree_rcu(cset, rcu_head); } -static void put_css_set(struct css_set *cset) -{ - unsigned long flags; - - /* - * Ensure that the refcount doesn't hit zero while any readers - * can see it. Similar to atomic_dec_and_lock(), but for an - * rwlock - */ - if (atomic_add_unless(&cset->refcount, -1, 1)) - return; - - spin_lock_irqsave(&css_set_lock, flags); - put_css_set_locked(cset); - spin_unlock_irqrestore(&css_set_lock, flags); -} - -/* - * refcounted get/put for css_set objects - */ -static inline void get_css_set(struct css_set *cset) -{ - atomic_inc(&cset->refcount); -} - /** * compare_css_sets - helper function for find_existing_css_set(). * @cset: candidate css_set being tested @@ -1095,13 +977,13 @@ static struct css_set *find_css_set(struct css_set *old_cset, } atomic_set(&cset->refcount, 1); - INIT_LIST_HEAD(&cset->cgrp_links); INIT_LIST_HEAD(&cset->tasks); INIT_LIST_HEAD(&cset->mg_tasks); - INIT_LIST_HEAD(&cset->mg_preload_node); - INIT_LIST_HEAD(&cset->mg_node); INIT_LIST_HEAD(&cset->task_iters); INIT_HLIST_NODE(&cset->hlist); + INIT_LIST_HEAD(&cset->cgrp_links); + INIT_LIST_HEAD(&cset->mg_preload_node); + INIT_LIST_HEAD(&cset->mg_node); /* Copy the set of subsystem state objects generated in * find_existing_css_set() */ @@ -1138,7 +1020,7 @@ static struct css_set *find_css_set(struct css_set *old_cset, 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; @@ -1166,7 +1048,7 @@ static void cgroup_exit_root_id(struct cgroup_root *root) idr_remove(&cgroup_hierarchy_idr, root->hierarchy_id); } -static void cgroup_free_root(struct cgroup_root *root) +void cgroup_free_root(struct cgroup_root *root) { if (root) { idr_destroy(&root->cgroup_idr); @@ -1283,8 +1165,8 @@ static struct cgroup *cset_cgroup_from_root(struct css_set *cset, * 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 @@ -1321,7 +1203,6 @@ static struct cgroup *task_cgroup_from_root(struct task_struct *task, */ 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) @@ -1415,7 +1296,7 @@ static u16 cgroup_calc_subtree_ss_mask(u16 subtree_control, u16 this_ss_mask) * 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; @@ -1447,8 +1328,7 @@ static void cgroup_kn_unlock(struct kernfs_node *kn) * 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; @@ -1532,9 +1412,9 @@ static int css_populate_dir(struct cgroup_subsys_state *css) if (!css->ss) { if (cgroup_on_dfl(cgrp)) - cfts = cgroup_dfl_base_files; + cfts = cgroup_base_files; else - cfts = cgroup_legacy_base_files; + cfts = cgroup1_base_files; return cgroup_addrm_files(&cgrp->self, cgrp, cfts, true); } @@ -1559,7 +1439,7 @@ err: 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; @@ -1629,8 +1509,8 @@ static int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask) return 0; } -static int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node, - struct kernfs_root *kf_root) +int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node, + struct kernfs_root *kf_root) { int len = 0; char *buf = NULL; @@ -1656,237 +1536,10 @@ static int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node, return len; } -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; - int ssid; - - if (root != &cgrp_dfl_root) - for_each_subsys(ss, ssid) - if (root->subsys_mask & (1 << ssid)) - seq_show_option(seq, ss->legacy_name, NULL); - if (root->flags & CGRP_ROOT_NOPREFIX) - seq_puts(seq, ",noprefix"); - if (root->flags & CGRP_ROOT_XATTR) - seq_puts(seq, ",xattr"); - - spin_lock(&release_agent_path_lock); - if (strlen(root->release_agent_path)) - seq_show_option(seq, "release_agent", - root->release_agent_path); - spin_unlock(&release_agent_path_lock); - - if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags)) - seq_puts(seq, ",clone_children"); - if (strlen(root->name)) - seq_show_option(seq, "name", root->name); - return 0; -} - -struct cgroup_sb_opts { - u16 subsys_mask; - unsigned int flags; - char *release_agent; - bool cpuset_clone_children; - char *name; - /* User explicitly requested empty subsystem */ - bool none; -}; - -static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) -{ - char *token, *o = data; - bool all_ss = false, one_ss = false; - u16 mask = U16_MAX; - struct cgroup_subsys *ss; - int nr_opts = 0; - int i; - -#ifdef CONFIG_CPUSETS - mask = ~((u16)1 << cpuset_cgrp_id); -#endif - - memset(opts, 0, sizeof(*opts)); - - while ((token = strsep(&o, ",")) != NULL) { - nr_opts++; - - if (!*token) - return -EINVAL; - if (!strcmp(token, "none")) { - /* Explicitly have no subsystems */ - opts->none = true; - continue; - } - if (!strcmp(token, "all")) { - /* Mutually exclusive option 'all' + subsystem name */ - if (one_ss) - return -EINVAL; - all_ss = true; - continue; - } - if (!strcmp(token, "noprefix")) { - opts->flags |= CGRP_ROOT_NOPREFIX; - continue; - } - if (!strcmp(token, "clone_children")) { - opts->cpuset_clone_children = true; - continue; - } - if (!strcmp(token, "xattr")) { - opts->flags |= CGRP_ROOT_XATTR; - continue; - } - if (!strncmp(token, "release_agent=", 14)) { - /* Specifying two release agents is forbidden */ - if (opts->release_agent) - return -EINVAL; - opts->release_agent = - kstrndup(token + 14, PATH_MAX - 1, GFP_KERNEL); - if (!opts->release_agent) - return -ENOMEM; - continue; - } - if (!strncmp(token, "name=", 5)) { - const char *name = token + 5; - /* Can't specify an empty name */ - if (!strlen(name)) - return -EINVAL; - /* Must match [\w.-]+ */ - for (i = 0; i < strlen(name); i++) { - char c = name[i]; - if (isalnum(c)) - continue; - if ((c == '.') || (c == '-') || (c == '_')) - continue; - return -EINVAL; - } - /* Specifying two names is forbidden */ - if (opts->name) - return -EINVAL; - opts->name = kstrndup(name, - MAX_CGROUP_ROOT_NAMELEN - 1, - GFP_KERNEL); - if (!opts->name) - return -ENOMEM; - - continue; - } - - for_each_subsys(ss, i) { - if (strcmp(token, ss->legacy_name)) - continue; - if (!cgroup_ssid_enabled(i)) - continue; - if (cgroup_ssid_no_v1(i)) - continue; - - /* Mutually exclusive option 'all' + subsystem name */ - if (all_ss) - return -EINVAL; - opts->subsys_mask |= (1 << i); - one_ss = true; - - break; - } - if (i == CGROUP_SUBSYS_COUNT) - return -ENOENT; - } - - /* - * If the 'all' option was specified select all the subsystems, - * otherwise if 'none', 'name=' and a subsystem name options were - * not specified, let's default to 'all' - */ - if (all_ss || (!one_ss && !opts->none && !opts->name)) - for_each_subsys(ss, i) - if (cgroup_ssid_enabled(i) && !cgroup_ssid_no_v1(i)) - opts->subsys_mask |= (1 << i); - - /* - * We either have to specify by name or by subsystems. (So all - * empty hierarchies must have a name). - */ - if (!opts->subsys_mask && !opts->name) - return -EINVAL; - - /* - * Option noprefix was introduced just for backward compatibility - * with the old cpuset, so we allow noprefix only if mounting just - * the cpuset subsystem. - */ - if ((opts->flags & CGRP_ROOT_NOPREFIX) && (opts->subsys_mask & mask)) - return -EINVAL; - - /* Can't specify "none" and some subsystems */ - if (opts->subsys_mask && opts->none) - return -EINVAL; - - return 0; -} - static int cgroup_remount(struct kernfs_root *kf_root, int *flags, char *data) { - int ret = 0; - struct cgroup_root *root = cgroup_root_from_kf(kf_root); - struct cgroup_sb_opts opts; - u16 added_mask, removed_mask; - - if (root == &cgrp_dfl_root) { - pr_err("remount is not allowed\n"); - return -EINVAL; - } - - cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp); - - /* See what subsystems are wanted */ - ret = parse_cgroupfs_options(data, &opts); - if (ret) - goto out_unlock; - - if (opts.subsys_mask != root->subsys_mask || opts.release_agent) - pr_warn("option changes via remount are deprecated (pid=%d comm=%s)\n", - task_tgid_nr(current), current->comm); - - added_mask = opts.subsys_mask & ~root->subsys_mask; - removed_mask = root->subsys_mask & ~opts.subsys_mask; - - /* Don't allow flags or name to change at remount */ - if ((opts.flags ^ root->flags) || - (opts.name && strcmp(opts.name, root->name))) { - pr_err("option or name mismatch, new: 0x%x \"%s\", old: 0x%x \"%s\"\n", - opts.flags, opts.name ?: "", root->flags, root->name); - ret = -EINVAL; - goto out_unlock; - } - - /* remounting is not allowed for populated hierarchies */ - if (!list_empty(&root->cgrp.self.children)) { - ret = -EBUSY; - goto out_unlock; - } - - ret = rebind_subsystems(root, added_mask); - if (ret) - goto out_unlock; - - WARN_ON(rebind_subsystems(&cgrp_dfl_root, removed_mask)); - - if (opts.release_agent) { - spin_lock(&release_agent_path_lock); - strcpy(root->release_agent_path, opts.release_agent); - spin_unlock(&release_agent_path_lock); - } - - trace_cgroup_remount(root); - - out_unlock: - kfree(opts.release_agent); - kfree(opts.name); - mutex_unlock(&cgroup_mutex); - return ret; + pr_err("remount is not allowed\n"); + return -EINVAL; } /* @@ -1964,11 +1617,10 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp) INIT_LIST_HEAD(&cgrp->e_csets[ssid]); init_waitqueue_head(&cgrp->offline_waitq); - INIT_WORK(&cgrp->release_agent_work, cgroup_release_agent); + INIT_WORK(&cgrp->release_agent_work, cgroup1_release_agent); } -static void init_cgroup_root(struct cgroup_root *root, - struct cgroup_sb_opts *opts) +void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts) { struct cgroup *cgrp = &root->cgrp; @@ -1987,10 +1639,11 @@ static void init_cgroup_root(struct cgroup_root *root, set_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags); } -static int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask) +int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask) { LIST_HEAD(tmp_links); struct cgroup *root_cgrp = &root->cgrp; + struct kernfs_syscall_ops *kf_sops; struct css_set *cset; int i, ret; @@ -2022,7 +1675,10 @@ static int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask) if (ret) goto cancel_ref; - root->kf_root = kernfs_create_root(&cgroup_kf_syscall_ops, + kf_sops = root == &cgrp_dfl_root ? + &cgroup_kf_syscall_ops : &cgroup1_kf_syscall_ops; + + root->kf_root = kernfs_create_root(kf_sops, KERNFS_ROOT_CREATE_DEACTIVATED, root_cgrp); if (IS_ERR(root->kf_root)) { @@ -2080,182 +1736,18 @@ out: return ret; } -static struct dentry *cgroup_mount(struct file_system_type *fs_type, - int flags, const char *unused_dev_name, - void *data) +struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags, + struct cgroup_root *root, unsigned long magic, + struct cgroup_namespace *ns) { - bool is_v2 = fs_type == &cgroup2_fs_type; - struct super_block *pinned_sb = NULL; - struct cgroup_namespace *ns = current->nsproxy->cgroup_ns; - struct cgroup_subsys *ss; - struct cgroup_root *root; - struct cgroup_sb_opts opts; struct dentry *dentry; - int ret; - int i; bool new_sb; - get_cgroup_ns(ns); - - /* Check if the caller has permission to mount. */ - if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) { - put_cgroup_ns(ns); - return ERR_PTR(-EPERM); - } - - /* - * The first time anyone tries to mount a cgroup, enable the list - * linking each css_set to its tasks and fix up all existing tasks. - */ - if (!use_task_css_set_links) - cgroup_enable_task_cg_lists(); - - if (is_v2) { - if (data) { - pr_err("cgroup2: unknown option \"%s\"\n", (char *)data); - put_cgroup_ns(ns); - return ERR_PTR(-EINVAL); - } - cgrp_dfl_visible = true; - root = &cgrp_dfl_root; - cgroup_get(&root->cgrp); - goto out_mount; - } - - cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp); - - /* First find the desired set of subsystems */ - ret = parse_cgroupfs_options(data, &opts); - if (ret) - goto out_unlock; - - /* - * Destruction of cgroup root is asynchronous, so subsystems may - * still be dying after the previous unmount. Let's drain the - * dying subsystems. We just need to ensure that the ones - * unmounted previously finish dying and don't care about new ones - * starting. Testing ref liveliness is good enough. - */ - for_each_subsys(ss, i) { - if (!(opts.subsys_mask & (1 << i)) || - ss->root == &cgrp_dfl_root) - continue; - - if (!percpu_ref_tryget_live(&ss->root->cgrp.self.refcnt)) { - mutex_unlock(&cgroup_mutex); - msleep(10); - ret = restart_syscall(); - goto out_free; - } - cgroup_put(&ss->root->cgrp); - } - - for_each_root(root) { - bool name_match = false; - - if (root == &cgrp_dfl_root) - continue; - - /* - * If we asked for a name then it must match. Also, if - * name matches but sybsys_mask doesn't, we should fail. - * Remember whether name matched. - */ - if (opts.name) { - if (strcmp(opts.name, root->name)) - continue; - name_match = true; - } - - /* - * If we asked for subsystems (or explicitly for no - * subsystems) then they must match. - */ - if ((opts.subsys_mask || opts.none) && - (opts.subsys_mask != root->subsys_mask)) { - if (!name_match) - continue; - ret = -EBUSY; - goto out_unlock; - } - - if (root->flags ^ opts.flags) - pr_warn("new mount options do not match the existing superblock, will be ignored\n"); - - /* - * We want to reuse @root whose lifetime is governed by its - * ->cgrp. Let's check whether @root is alive and keep it - * that way. As cgroup_kill_sb() can happen anytime, we - * want to block it by pinning the sb so that @root doesn't - * get killed before mount is complete. - * - * With the sb pinned, tryget_live can reliably indicate - * whether @root can be reused. If it's being killed, - * drain it. We can use wait_queue for the wait but this - * path is super cold. Let's just sleep a bit and retry. - */ - pinned_sb = kernfs_pin_sb(root->kf_root, NULL); - if (IS_ERR(pinned_sb) || - !percpu_ref_tryget_live(&root->cgrp.self.refcnt)) { - mutex_unlock(&cgroup_mutex); - if (!IS_ERR_OR_NULL(pinned_sb)) - deactivate_super(pinned_sb); - msleep(10); - ret = restart_syscall(); - goto out_free; - } - - ret = 0; - goto out_unlock; - } + dentry = kernfs_mount(fs_type, flags, root->kf_root, magic, &new_sb); /* - * No such thing, create a new one. name= matching without subsys - * specification is allowed for already existing hierarchies but we - * can't create new one without subsys specification. - */ - if (!opts.subsys_mask && !opts.none) { - ret = -EINVAL; - goto out_unlock; - } - - /* Hierarchies may only be created in the initial cgroup namespace. */ - if (ns != &init_cgroup_ns) { - ret = -EPERM; - goto out_unlock; - } - - root = kzalloc(sizeof(*root), GFP_KERNEL); - if (!root) { - ret = -ENOMEM; - goto out_unlock; - } - - init_cgroup_root(root, &opts); - - ret = cgroup_setup_root(root, opts.subsys_mask); - if (ret) - cgroup_free_root(root); - -out_unlock: - mutex_unlock(&cgroup_mutex); -out_free: - kfree(opts.release_agent); - kfree(opts.name); - - if (ret) { - put_cgroup_ns(ns); - return ERR_PTR(ret); - } -out_mount: - dentry = kernfs_mount(fs_type, flags, root->kf_root, - is_v2 ? CGROUP2_SUPER_MAGIC : CGROUP_SUPER_MAGIC, - &new_sb); - - /* - * In non-init cgroup namespace, instead of root cgroup's - * dentry, we return the dentry corresponding to the - * cgroupns->root_cgrp. + * In non-init cgroup namespace, instead of root cgroup's dentry, + * we return the dentry corresponding to the cgroupns->root_cgrp. */ if (!IS_ERR(dentry) && ns != &init_cgroup_ns) { struct dentry *nsdentry; @@ -2277,13 +1769,45 @@ out_mount: if (IS_ERR(dentry) || !new_sb) cgroup_put(&root->cgrp); + return dentry; +} + +static struct dentry *cgroup_mount(struct file_system_type *fs_type, + int flags, const char *unused_dev_name, + void *data) +{ + struct cgroup_namespace *ns = current->nsproxy->cgroup_ns; + struct dentry *dentry; + + get_cgroup_ns(ns); + + /* Check if the caller has permission to mount. */ + if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) { + put_cgroup_ns(ns); + return ERR_PTR(-EPERM); + } + /* - * If @pinned_sb, we're reusing an existing root and holding an - * extra ref on its sb. Mount is complete. Put the extra ref. + * The first time anyone tries to mount a cgroup, enable the list + * linking each css_set to its tasks and fix up all existing tasks. */ - if (pinned_sb) { - WARN_ON(new_sb); - deactivate_super(pinned_sb); + if (!use_task_css_set_links) + cgroup_enable_task_cg_lists(); + + if (fs_type == &cgroup2_fs_type) { + if (data) { + pr_err("cgroup2: unknown option \"%s\"\n", (char *)data); + put_cgroup_ns(ns); + return ERR_PTR(-EINVAL); + } + cgrp_dfl_visible = true; + cgroup_get(&cgrp_dfl_root.cgrp); + + dentry = cgroup_do_mount(&cgroup2_fs_type, flags, &cgrp_dfl_root, + CGROUP2_SUPER_MAGIC, ns); + } else { + dentry = cgroup1_mount(&cgroup_fs_type, flags, data, + CGROUP_SUPER_MAGIC, ns); } put_cgroup_ns(ns); @@ -2311,7 +1835,7 @@ static void cgroup_kill_sb(struct super_block *sb) 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, @@ -2325,8 +1849,8 @@ static struct file_system_type cgroup2_fs_type = { .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); @@ -2389,49 +1913,18 @@ int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen) } EXPORT_SYMBOL_GPL(task_cgroup_path); -/* used to track tasks and other necessary states during migration */ -struct cgroup_taskset { - /* the src and dst cset list running through cset->mg_node */ - struct list_head src_csets; - struct list_head dst_csets; - - /* the subsys currently being processed */ - int ssid; - - /* - * Fields for cgroup_taskset_*() iteration. - * - * Before migration is committed, the target migration tasks are on - * ->mg_tasks of the csets on ->src_csets. After, on ->mg_tasks of - * the csets on ->dst_csets. ->csets point to either ->src_csets - * or ->dst_csets depending on whether migration is committed. - * - * ->cur_csets and ->cur_task point to the current task position - * during iteration. - */ - struct list_head *csets; - struct css_set *cur_cset; - struct task_struct *cur_task; -}; - -#define CGROUP_TASKSET_INIT(tset) (struct cgroup_taskset){ \ - .src_csets = LIST_HEAD_INIT(tset.src_csets), \ - .dst_csets = LIST_HEAD_INIT(tset.dst_csets), \ - .csets = &tset.src_csets, \ -} - /** - * cgroup_taskset_add - try to add a migration target task to a taskset + * cgroup_migrate_add_task - add a migration target task to a migration context * @task: target task - * @tset: target taskset + * @mgctx: target migration context * - * Add @task, which is a migration target, to @tset. This function becomes - * noop if @task doesn't need to be migrated. @task's css_set should have - * been added as a migration source and @task->cg_list will be moved from - * the css_set's tasks list to mg_tasks one. + * Add @task, which is a migration target, to @mgctx->tset. This function + * becomes noop if @task doesn't need to be migrated. @task's css_set + * should have been added as a migration source and @task->cg_list will be + * moved from the css_set's tasks list to mg_tasks one. */ -static void cgroup_taskset_add(struct task_struct *task, - struct cgroup_taskset *tset) +static void cgroup_migrate_add_task(struct task_struct *task, + struct cgroup_mgctx *mgctx) { struct css_set *cset; @@ -2451,10 +1944,11 @@ static void cgroup_taskset_add(struct task_struct *task, list_move_tail(&task->cg_list, &cset->mg_tasks); if (list_empty(&cset->mg_node)) - list_add_tail(&cset->mg_node, &tset->src_csets); + list_add_tail(&cset->mg_node, + &mgctx->tset.src_csets); if (list_empty(&cset->mg_dst_cset->mg_node)) - list_move_tail(&cset->mg_dst_cset->mg_node, - &tset->dst_csets); + list_add_tail(&cset->mg_dst_cset->mg_node, + &mgctx->tset.dst_csets); } /** @@ -2521,17 +2015,16 @@ struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset, /** * cgroup_taskset_migrate - migrate a taskset - * @tset: taget taskset - * @root: cgroup root the migration is taking place on + * @mgctx: migration context * - * Migrate tasks in @tset as setup by migration preparation functions. + * Migrate tasks in @mgctx as setup by migration preparation functions. * This function fails iff one of the ->can_attach callbacks fails and - * guarantees that either all or none of the tasks in @tset are migrated. - * @tset is consumed regardless of success. + * guarantees that either all or none of the tasks in @mgctx are migrated. + * @mgctx is consumed regardless of success. */ -static int cgroup_taskset_migrate(struct cgroup_taskset *tset, - struct cgroup_root *root) +static int cgroup_migrate_execute(struct cgroup_mgctx *mgctx) { + struct cgroup_taskset *tset = &mgctx->tset; struct cgroup_subsys *ss; struct task_struct *task, *tmp_task; struct css_set *cset, *tmp_cset; @@ -2542,7 +2035,7 @@ static int cgroup_taskset_migrate(struct cgroup_taskset *tset, return 0; /* check that we can legitimately attach to the cgroup */ - do_each_subsys_mask(ss, ssid, root->subsys_mask) { + do_each_subsys_mask(ss, ssid, mgctx->ss_mask) { if (ss->can_attach) { tset->ssid = ssid; ret = ss->can_attach(tset); @@ -2578,7 +2071,7 @@ static int cgroup_taskset_migrate(struct cgroup_taskset *tset, */ tset->csets = &tset->dst_csets; - do_each_subsys_mask(ss, ssid, root->subsys_mask) { + do_each_subsys_mask(ss, ssid, mgctx->ss_mask) { if (ss->attach) { tset->ssid = ssid; ss->attach(tset); @@ -2589,7 +2082,7 @@ static int cgroup_taskset_migrate(struct cgroup_taskset *tset, goto out_release_tset; out_cancel_attach: - do_each_subsys_mask(ss, ssid, root->subsys_mask) { + do_each_subsys_mask(ss, ssid, mgctx->ss_mask) { if (ssid == failed_ssid) break; if (ss->cancel_attach) { @@ -2616,7 +2109,7 @@ out_release_tset: * 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; @@ -2624,25 +2117,31 @@ static bool cgroup_may_migrate_to(struct cgroup *dst_cgrp) /** * cgroup_migrate_finish - cleanup after attach - * @preloaded_csets: list of preloaded css_sets + * @mgctx: migration context * * 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 cgroup_mgctx *mgctx) { + LIST_HEAD(preloaded); struct css_set *cset, *tmp_cset; lockdep_assert_held(&cgroup_mutex); spin_lock_irq(&css_set_lock); - list_for_each_entry_safe(cset, tmp_cset, preloaded_csets, mg_preload_node) { + + list_splice_tail_init(&mgctx->preloaded_src_csets, &preloaded); + list_splice_tail_init(&mgctx->preloaded_dst_csets, &preloaded); + + list_for_each_entry_safe(cset, tmp_cset, &preloaded, mg_preload_node) { cset->mg_src_cgrp = NULL; cset->mg_dst_cgrp = NULL; cset->mg_dst_cset = NULL; list_del_init(&cset->mg_preload_node); put_css_set_locked(cset); } + spin_unlock_irq(&css_set_lock); } @@ -2650,10 +2149,10 @@ static void cgroup_migrate_finish(struct list_head *preloaded_csets) * cgroup_migrate_add_src - add a migration source css_set * @src_cset: the source css_set to add * @dst_cgrp: the destination cgroup - * @preloaded_csets: list of preloaded css_sets + * @mgctx: migration context * * Tasks belonging to @src_cset are about to be migrated to @dst_cgrp. Pin - * @src_cset and add it to @preloaded_csets, which should later be cleaned + * @src_cset and add it to @mgctx->src_csets, which should later be cleaned * up by cgroup_migrate_finish(). * * This function may be called without holding cgroup_threadgroup_rwsem @@ -2662,9 +2161,9 @@ static void cgroup_migrate_finish(struct list_head *preloaded_csets) * 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 cgroup_mgctx *mgctx) { struct cgroup *src_cgrp; @@ -2692,33 +2191,35 @@ static void cgroup_migrate_add_src(struct css_set *src_cset, src_cset->mg_src_cgrp = src_cgrp; src_cset->mg_dst_cgrp = dst_cgrp; get_css_set(src_cset); - list_add(&src_cset->mg_preload_node, preloaded_csets); + list_add_tail(&src_cset->mg_preload_node, &mgctx->preloaded_src_csets); } /** * cgroup_migrate_prepare_dst - prepare destination css_sets for migration - * @preloaded_csets: list of preloaded source css_sets + * @mgctx: migration context * * Tasks are about to be moved and all the source css_sets have been - * preloaded to @preloaded_csets. This function looks up and pins all - * destination css_sets, links each to its source, and append them to - * @preloaded_csets. + * preloaded to @mgctx->preloaded_src_csets. This function looks up and + * pins all destination css_sets, links each to its source, and append them + * to @mgctx->preloaded_dst_csets. * * This function must be called after cgroup_migrate_add_src() has been * called on each migration source css_set. After migration is performed * using cgroup_migrate(), cgroup_migrate_finish() must be called on - * @preloaded_csets. + * @mgctx. */ -static int cgroup_migrate_prepare_dst(struct list_head *preloaded_csets) +int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx) { - LIST_HEAD(csets); struct css_set *src_cset, *tmp_cset; lockdep_assert_held(&cgroup_mutex); /* look up the dst cset for each src cset and link it to src */ - list_for_each_entry_safe(src_cset, tmp_cset, preloaded_csets, mg_preload_node) { + list_for_each_entry_safe(src_cset, tmp_cset, &mgctx->preloaded_src_csets, + mg_preload_node) { struct css_set *dst_cset; + struct cgroup_subsys *ss; + int ssid; dst_cset = find_css_set(src_cset, src_cset->mg_dst_cgrp); if (!dst_cset) @@ -2743,15 +2244,19 @@ static int cgroup_migrate_prepare_dst(struct list_head *preloaded_csets) src_cset->mg_dst_cset = dst_cset; if (list_empty(&dst_cset->mg_preload_node)) - list_add(&dst_cset->mg_preload_node, &csets); + list_add_tail(&dst_cset->mg_preload_node, + &mgctx->preloaded_dst_csets); else put_css_set(dst_cset); + + for_each_subsys(ss, ssid) + if (src_cset->subsys[ssid] != dst_cset->subsys[ssid]) + mgctx->ss_mask |= 1 << ssid; } - list_splice_tail(&csets, preloaded_csets); return 0; err: - cgroup_migrate_finish(&csets); + cgroup_migrate_finish(mgctx); return -ENOMEM; } @@ -2759,7 +2264,7 @@ err: * cgroup_migrate - migrate a process or task to a cgroup * @leader: the leader of the process or the task to migrate * @threadgroup: whether @leader points to the whole process or a single task - * @root: cgroup root migration is taking place on + * @mgctx: migration context * * Migrate a process or task denoted by @leader. If migrating a process, * the caller must be holding cgroup_threadgroup_rwsem. The caller is also @@ -2773,10 +2278,9 @@ err: * 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_mgctx *mgctx) { - struct cgroup_taskset tset = CGROUP_TASKSET_INIT(tset); struct task_struct *task; /* @@ -2788,14 +2292,14 @@ static int cgroup_migrate(struct task_struct *leader, bool threadgroup, rcu_read_lock(); task = leader; do { - cgroup_taskset_add(task, &tset); + cgroup_migrate_add_task(task, mgctx); if (!threadgroup) break; } while_each_thread(leader, task); rcu_read_unlock(); spin_unlock_irq(&css_set_lock); - return cgroup_taskset_migrate(&tset, root); + return cgroup_migrate_execute(mgctx); } /** @@ -2806,10 +2310,10 @@ static int cgroup_migrate(struct task_struct *leader, bool threadgroup, * * 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); + DEFINE_CGROUP_MGCTX(mgctx); struct task_struct *task; int ret; @@ -2821,8 +2325,7 @@ static int cgroup_attach_task(struct cgroup *dst_cgrp, rcu_read_lock(); task = leader; do { - cgroup_migrate_add_src(task_css_set(task), dst_cgrp, - &preloaded_csets); + cgroup_migrate_add_src(task_css_set(task), dst_cgrp, &mgctx); if (!threadgroup) break; } while_each_thread(leader, task); @@ -2830,11 +2333,11 @@ static int cgroup_attach_task(struct cgroup *dst_cgrp, spin_unlock_irq(&css_set_lock); /* prepare dst csets and commit */ - ret = cgroup_migrate_prepare_dst(&preloaded_csets); + ret = cgroup_migrate_prepare_dst(&mgctx); if (!ret) - ret = cgroup_migrate(leader, threadgroup, dst_cgrp->root); + ret = cgroup_migrate(leader, threadgroup, &mgctx); - cgroup_migrate_finish(&preloaded_csets); + cgroup_migrate_finish(&mgctx); if (!ret) trace_cgroup_attach_task(dst_cgrp, leader, threadgroup); @@ -2846,20 +2349,9 @@ static int cgroup_procs_write_permission(struct task_struct *task, struct cgroup *dst_cgrp, struct kernfs_open_file *of) { - const struct cred *cred = current_cred(); - const struct cred *tcred = get_task_cred(task); int ret = 0; - /* - * even if we're attaching all tasks in the thread group, we only - * need to check permissions on one of them. - */ - if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) && - !uid_eq(cred->euid, tcred->uid) && - !uid_eq(cred->euid, tcred->suid)) - ret = -EACCES; - - if (!ret && cgroup_on_dfl(dst_cgrp)) { + if (cgroup_on_dfl(dst_cgrp)) { struct super_block *sb = of->file->f_path.dentry->d_sb; struct cgroup *cgrp; struct inode *inode; @@ -2877,9 +2369,21 @@ static int cgroup_procs_write_permission(struct task_struct *task, ret = inode_permission(inode, MAY_WRITE); iput(inode); } + } else { + const struct cred *cred = current_cred(); + const struct cred *tcred = get_task_cred(task); + + /* + * even if we're attaching all tasks in the thread group, + * we only need to check permissions on one of them. + */ + if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) && + !uid_eq(cred->euid, tcred->uid) && + !uid_eq(cred->euid, tcred->suid)) + ret = -EACCES; + put_cred(tcred); } - put_cred(tcred); return ret; } @@ -2888,8 +2392,8 @@ static int cgroup_procs_write_permission(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; @@ -2950,86 +2454,12 @@ out_unlock_threadgroup: 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; @@ -3075,8 +2505,7 @@ static int cgroup_subtree_control_show(struct seq_file *seq, void *v) */ static int cgroup_update_dfl_csses(struct cgroup *cgrp) { - LIST_HEAD(preloaded_csets); - struct cgroup_taskset tset = CGROUP_TASKSET_INIT(tset); + DEFINE_CGROUP_MGCTX(mgctx); struct cgroup_subsys_state *d_css; struct cgroup *dsct; struct css_set *src_cset; @@ -3092,33 +2521,28 @@ static int cgroup_update_dfl_csses(struct cgroup *cgrp) struct cgrp_cset_link *link; list_for_each_entry(link, &dsct->cset_links, cset_link) - cgroup_migrate_add_src(link->cset, dsct, - &preloaded_csets); + cgroup_migrate_add_src(link->cset, dsct, &mgctx); } spin_unlock_irq(&css_set_lock); /* NULL dst indicates self on default hierarchy */ - ret = cgroup_migrate_prepare_dst(&preloaded_csets); + ret = cgroup_migrate_prepare_dst(&mgctx); if (ret) goto out_finish; spin_lock_irq(&css_set_lock); - list_for_each_entry(src_cset, &preloaded_csets, mg_preload_node) { + list_for_each_entry(src_cset, &mgctx.preloaded_src_csets, mg_preload_node) { struct task_struct *task, *ntask; - /* src_csets precede dst_csets, break on the first dst_cset */ - if (!src_cset->mg_src_cgrp) - break; - /* all tasks in src_csets need to be migrated */ list_for_each_entry_safe(task, ntask, &src_cset->tasks, cg_list) - cgroup_taskset_add(task, &tset); + cgroup_migrate_add_task(task, &mgctx); } spin_unlock_irq(&css_set_lock); - ret = cgroup_taskset_migrate(&tset, cgrp->root); + ret = cgroup_migrate_execute(&mgctx); out_finish: - cgroup_migrate_finish(&preloaded_csets); + cgroup_migrate_finish(&mgctx); percpu_up_write(&cgroup_threadgroup_rwsem); return ret; } @@ -3131,7 +2555,7 @@ out_finish: * 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; @@ -3503,6 +2927,23 @@ static int cgroup_events_show(struct seq_file *seq, void *v) return 0; } +static int cgroup_file_open(struct kernfs_open_file *of) +{ + struct cftype *cft = of->kn->priv; + + if (cft->open) + return cft->open(of); + return 0; +} + +static void cgroup_file_release(struct kernfs_open_file *of) +{ + struct cftype *cft = of->kn->priv; + + if (cft->release) + cft->release(of); +} + static ssize_t cgroup_file_write(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { @@ -3553,7 +2994,8 @@ static void *cgroup_seqfile_next(struct seq_file *seq, void *v, loff_t *ppos) static void cgroup_seqfile_stop(struct seq_file *seq, void *v) { - seq_cft(seq)->seq_stop(seq, v); + if (seq_cft(seq)->seq_stop) + seq_cft(seq)->seq_stop(seq, v); } static int cgroup_seqfile_show(struct seq_file *m, void *arg) @@ -3575,12 +3017,16 @@ static int cgroup_seqfile_show(struct seq_file *m, void *arg) static struct kernfs_ops cgroup_kf_single_ops = { .atomic_write_len = PAGE_SIZE, + .open = cgroup_file_open, + .release = cgroup_file_release, .write = cgroup_file_write, .seq_show = cgroup_seqfile_show, }; static struct kernfs_ops cgroup_kf_ops = { .atomic_write_len = PAGE_SIZE, + .open = cgroup_file_open, + .release = cgroup_file_release, .write = cgroup_file_write, .seq_start = cgroup_seqfile_start, .seq_next = cgroup_seqfile_next, @@ -3588,48 +3034,6 @@ static struct kernfs_ops cgroup_kf_ops = { .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) { @@ -3926,26 +3330,6 @@ void cgroup_file_notify(struct cgroup_file *cfile) } /** - * 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) * @parent: css whose children to walk @@ -4343,560 +3727,69 @@ void css_task_iter_end(struct css_task_iter *it) 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_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. - */ -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. - * - * All this extra complexity was caused by the original implementation - * committing to an entirely unnecessary property. In the long term, we - * want to do away with it. Explicitly scramble sort order if on the - * default hierarchy so that no such expectation exists in the new - * interface. - * - * Scrambling is done by swapping every two consecutive bits, which is - * non-identity one-to-one mapping which disturbs sort order sufficiently. - */ -static pid_t pid_fry(pid_t pid) +static void cgroup_procs_release(struct kernfs_open_file *of) { - unsigned a = pid & 0x55555555; - unsigned b = pid & 0xAAAAAAAA; - - return (a << 1) | (b >> 1); -} - -static pid_t cgroup_pid_fry(struct cgroup *cgrp, pid_t pid) -{ - if (cgroup_on_dfl(cgrp)) - return pid_fry(pid); - else - return pid; -} - -static int cmppid(const void *a, const void *b) -{ - return *(pid_t *)a - *(pid_t *)b; -} - -static int fried_cmppid(const void *a, const void *b) -{ - return pid_fry(*(pid_t *)a) - pid_fry(*(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 */ - if (cgroup_on_dfl(cgrp)) - sort(array, length, sizeof(pid_t), fried_cmppid, NULL); - else - 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; + if (of->priv) { + css_task_iter_end(of->priv); + kfree(of->priv); } - - /* 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) +static void *cgroup_procs_next(struct seq_file *s, void *v, loff_t *pos) { - 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(); + struct kernfs_open_file *of = s->private; + struct css_task_iter *it = of->priv; + struct task_struct *task; - 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); + do { + task = css_task_iter_next(it); + } while (task && !thread_group_leader(task)); - mutex_unlock(&cgroup_mutex); - return 0; + return task; } - -/* - * 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) +static void *cgroup_procs_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); + struct css_task_iter *it = of->priv; /* - * !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. + * When a seq_file is seeked, it's always traversed sequentially + * from position 0, so we can simply keep iterating on !0 *pos. */ - 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 (cgroup_pid_fry(cgrp, l->list[mid]) == pid) { - index = mid; - break; - } else if (cgroup_pid_fry(cgrp, 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 = cgroup_pid_fry(cgrp, *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); -} + if (!it) { + if (WARN_ON_ONCE((*pos)++)) + return ERR_PTR(-EINVAL); -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 = cgroup_pid_fry(seq_css(s)->cgroup, *p); - return p; + it = kzalloc(sizeof(*it), GFP_KERNEL); + if (!it) + return ERR_PTR(-ENOMEM); + of->priv = it; + css_task_iter_start(&cgrp->self, it); + } else if (!(*pos)++) { + css_task_iter_end(it); + css_task_iter_start(&cgrp->self, it); } -} - -static int cgroup_pidlist_show(struct seq_file *s, void *v) -{ - seq_printf(s, "%d\n", *(int *)v); - return 0; + return cgroup_procs_next(s, NULL, NULL); } -static u64 cgroup_read_notify_on_release(struct cgroup_subsys_state *css, - struct cftype *cft) +static int cgroup_procs_show(struct seq_file *s, void *v) { - 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); + seq_printf(s, "%d\n", task_tgid_vnr(v)); return 0; } /* cgroup core interface files for the default hierarchy */ -static struct cftype cgroup_dfl_base_files[] = { +static struct cftype cgroup_base_files[] = { { .name = "cgroup.procs", .file_offset = offsetof(struct cgroup, procs_file), - .seq_start = cgroup_pidlist_start, - .seq_next = cgroup_pidlist_next, - .seq_stop = cgroup_pidlist_stop, - .seq_show = cgroup_pidlist_show, - .private = CGROUP_FILE_PROCS, + .release = cgroup_procs_release, + .seq_start = cgroup_procs_start, + .seq_next = cgroup_procs_next, + .seq_show = cgroup_procs_show, .write = cgroup_procs_write, }, { @@ -4917,51 +3810,6 @@ 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. * @@ -5007,7 +3855,7 @@ static void css_free_work_fn(struct work_struct *work) } else { /* cgroup free path */ atomic_dec(&cgrp->root->nr_cgrps); - cgroup_pidlist_destroy_all(cgrp); + cgroup1_pidlist_destroy_all(cgrp); cancel_work_sync(&cgrp->release_agent_work); if (cgroup_parent(cgrp)) { @@ -5302,8 +4150,7 @@ out_free_cgrp: return ERR_PTR(ret); } -static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, - umode_t mode) +int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode) { struct cgroup *parent, *cgrp; struct kernfs_node *kn; @@ -5507,7 +4354,7 @@ static int cgroup_destroy_locked(struct cgroup *cgrp) */ kernfs_remove(cgrp->kn); - check_for_release(cgroup_parent(cgrp)); + cgroup1_check_for_release(cgroup_parent(cgrp)); /* put the base reference */ percpu_ref_kill(&cgrp->self.refcnt); @@ -5515,7 +4362,7 @@ static int cgroup_destroy_locked(struct cgroup *cgrp) return 0; }; -static int cgroup_rmdir(struct kernfs_node *kn) +int cgroup_rmdir(struct kernfs_node *kn) { struct cgroup *cgrp; int ret = 0; @@ -5535,10 +4382,8 @@ static int cgroup_rmdir(struct kernfs_node *kn) static struct kernfs_syscall_ops cgroup_kf_syscall_ops = { .remount_fs = cgroup_remount, - .show_options = cgroup_show_options, .mkdir = cgroup_mkdir, .rmdir = cgroup_rmdir, - .rename = cgroup_rename, .show_path = cgroup_show_path, }; @@ -5646,8 +4491,8 @@ int __init cgroup_init(void) BUILD_BUG_ON(CGROUP_SUBSYS_COUNT > 16); BUG_ON(percpu_init_rwsem(&cgroup_threadgroup_rwsem)); - BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files)); - BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files)); + BUG_ON(cgroup_init_cftypes(NULL, cgroup_base_files)); + BUG_ON(cgroup_init_cftypes(NULL, cgroup1_base_files)); /* * The latency of the synchronize_sched() is too high for cgroups, @@ -5697,7 +4542,7 @@ int __init cgroup_init(void) continue; } - if (cgroup_ssid_no_v1(ssid)) + if (cgroup1_ssid_disabled(ssid)) printk(KERN_INFO "Disabling %s control group subsystem in v1 mounts\n", ss->name); @@ -5744,15 +4589,6 @@ static int __init cgroup_wq_init(void) */ 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); @@ -5835,42 +4671,6 @@ out: 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. @@ -6050,76 +4850,6 @@ void cgroup_free(struct task_struct *task) 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; @@ -6141,33 +4871,6 @@ static int __init cgroup_disable(char *str) } __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 @@ -6197,7 +4900,7 @@ struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry, * have been or be removed at any point. @kn->priv is RCU * protected for this access. See css_release_work_fn() for details. */ - cgrp = rcu_dereference(kn->priv); + cgrp = rcu_dereference(*(void __rcu __force **)&kn->priv); if (cgrp) css = cgroup_css(cgrp, ss); @@ -6349,154 +5052,6 @@ void cgroup_sk_free(struct sock_cgroup_data *skcd) #endif /* CONFIG_SOCK_CGROUP_DATA */ -/* cgroup namespaces */ - -static struct ucounts *inc_cgroup_namespaces(struct user_namespace *ns) -{ - return inc_ucount(ns, current_euid(), UCOUNT_CGROUP_NAMESPACES); -} - -static void dec_cgroup_namespaces(struct ucounts *ucounts) -{ - dec_ucount(ucounts, UCOUNT_CGROUP_NAMESPACES); -} - -static struct cgroup_namespace *alloc_cgroup_ns(void) -{ - struct cgroup_namespace *new_ns; - int ret; - - new_ns = kzalloc(sizeof(struct cgroup_namespace), GFP_KERNEL); - if (!new_ns) - return ERR_PTR(-ENOMEM); - ret = ns_alloc_inum(&new_ns->ns); - if (ret) { - kfree(new_ns); - return ERR_PTR(ret); - } - atomic_set(&new_ns->count, 1); - new_ns->ns.ops = &cgroupns_operations; - return new_ns; -} - -void free_cgroup_ns(struct cgroup_namespace *ns) -{ - put_css_set(ns->root_cset); - dec_cgroup_namespaces(ns->ucounts); - put_user_ns(ns->user_ns); - ns_free_inum(&ns->ns); - kfree(ns); -} -EXPORT_SYMBOL(free_cgroup_ns); - -struct cgroup_namespace *copy_cgroup_ns(unsigned long flags, - struct user_namespace *user_ns, - struct cgroup_namespace *old_ns) -{ - struct cgroup_namespace *new_ns; - struct ucounts *ucounts; - struct css_set *cset; - - BUG_ON(!old_ns); - - if (!(flags & CLONE_NEWCGROUP)) { - get_cgroup_ns(old_ns); - return old_ns; - } - - /* Allow only sysadmin to create cgroup namespace. */ - if (!ns_capable(user_ns, CAP_SYS_ADMIN)) - return ERR_PTR(-EPERM); - - ucounts = inc_cgroup_namespaces(user_ns); - if (!ucounts) - return ERR_PTR(-ENOSPC); - - /* It is not safe to take cgroup_mutex here */ - spin_lock_irq(&css_set_lock); - cset = task_css_set(current); - get_css_set(cset); - spin_unlock_irq(&css_set_lock); - - new_ns = alloc_cgroup_ns(); - if (IS_ERR(new_ns)) { - put_css_set(cset); - dec_cgroup_namespaces(ucounts); - return new_ns; - } - - new_ns->user_ns = get_user_ns(user_ns); - new_ns->ucounts = ucounts; - new_ns->root_cset = cset; - - return new_ns; -} - -static inline struct cgroup_namespace *to_cg_ns(struct ns_common *ns) -{ - return container_of(ns, struct cgroup_namespace, ns); -} - -static int cgroupns_install(struct nsproxy *nsproxy, struct ns_common *ns) -{ - struct cgroup_namespace *cgroup_ns = to_cg_ns(ns); - - if (!ns_capable(current_user_ns(), CAP_SYS_ADMIN) || - !ns_capable(cgroup_ns->user_ns, CAP_SYS_ADMIN)) - return -EPERM; - - /* Don't need to do anything if we are attaching to our own cgroupns. */ - if (cgroup_ns == nsproxy->cgroup_ns) - return 0; - - get_cgroup_ns(cgroup_ns); - put_cgroup_ns(nsproxy->cgroup_ns); - nsproxy->cgroup_ns = cgroup_ns; - - return 0; -} - -static struct ns_common *cgroupns_get(struct task_struct *task) -{ - struct cgroup_namespace *ns = NULL; - struct nsproxy *nsproxy; - - task_lock(task); - nsproxy = task->nsproxy; - if (nsproxy) { - ns = nsproxy->cgroup_ns; - get_cgroup_ns(ns); - } - task_unlock(task); - - return ns ? &ns->ns : NULL; -} - -static void cgroupns_put(struct ns_common *ns) -{ - put_cgroup_ns(to_cg_ns(ns)); -} - -static struct user_namespace *cgroupns_owner(struct ns_common *ns) -{ - return to_cg_ns(ns)->user_ns; -} - -const struct proc_ns_operations cgroupns_operations = { - .name = "cgroup", - .type = CLONE_NEWCGROUP, - .get = cgroupns_get, - .put = cgroupns_put, - .install = cgroupns_install, - .owner = cgroupns_owner, -}; - -static __init int cgroup_namespaces_init(void) -{ - return 0; -} -subsys_initcall(cgroup_namespaces_init); - #ifdef CONFIG_CGROUP_BPF int cgroup_bpf_update(struct cgroup *cgrp, struct bpf_prog *prog, enum bpf_attach_type type, bool overridable) @@ -6510,149 +5065,3 @@ int cgroup_bpf_update(struct cgroup *cgrp, struct bpf_prog *prog, return ret; } #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 */ diff --git a/kernel/cpuset.c b/kernel/cgroup/cpuset.c index b3088886cd37..b3088886cd37 100644 --- a/kernel/cpuset.c +++ b/kernel/cgroup/cpuset.c diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup/freezer.c index 1b72d56edce5..1b72d56edce5 100644 --- a/kernel/cgroup_freezer.c +++ b/kernel/cgroup/freezer.c diff --git a/kernel/cgroup/namespace.c b/kernel/cgroup/namespace.c new file mode 100644 index 000000000000..cff7ea62c38f --- /dev/null +++ b/kernel/cgroup/namespace.c @@ -0,0 +1,155 @@ +#include "cgroup-internal.h" + +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/nsproxy.h> +#include <linux/proc_ns.h> + + +/* cgroup namespaces */ + +static struct ucounts *inc_cgroup_namespaces(struct user_namespace *ns) +{ + return inc_ucount(ns, current_euid(), UCOUNT_CGROUP_NAMESPACES); +} + +static void dec_cgroup_namespaces(struct ucounts *ucounts) +{ + dec_ucount(ucounts, UCOUNT_CGROUP_NAMESPACES); +} + +static struct cgroup_namespace *alloc_cgroup_ns(void) +{ + struct cgroup_namespace *new_ns; + int ret; + + new_ns = kzalloc(sizeof(struct cgroup_namespace), GFP_KERNEL); + if (!new_ns) + return ERR_PTR(-ENOMEM); + ret = ns_alloc_inum(&new_ns->ns); + if (ret) { + kfree(new_ns); + return ERR_PTR(ret); + } + atomic_set(&new_ns->count, 1); + new_ns->ns.ops = &cgroupns_operations; + return new_ns; +} + +void free_cgroup_ns(struct cgroup_namespace *ns) +{ + put_css_set(ns->root_cset); + dec_cgroup_namespaces(ns->ucounts); + put_user_ns(ns->user_ns); + ns_free_inum(&ns->ns); + kfree(ns); +} +EXPORT_SYMBOL(free_cgroup_ns); + +struct cgroup_namespace *copy_cgroup_ns(unsigned long flags, + struct user_namespace *user_ns, + struct cgroup_namespace *old_ns) +{ + struct cgroup_namespace *new_ns; + struct ucounts *ucounts; + struct css_set *cset; + + BUG_ON(!old_ns); + + if (!(flags & CLONE_NEWCGROUP)) { + get_cgroup_ns(old_ns); + return old_ns; + } + + /* Allow only sysadmin to create cgroup namespace. */ + if (!ns_capable(user_ns, CAP_SYS_ADMIN)) + return ERR_PTR(-EPERM); + + ucounts = inc_cgroup_namespaces(user_ns); + if (!ucounts) + return ERR_PTR(-ENOSPC); + + /* It is not safe to take cgroup_mutex here */ + spin_lock_irq(&css_set_lock); + cset = task_css_set(current); + get_css_set(cset); + spin_unlock_irq(&css_set_lock); + + new_ns = alloc_cgroup_ns(); + if (IS_ERR(new_ns)) { + put_css_set(cset); + dec_cgroup_namespaces(ucounts); + return new_ns; + } + + new_ns->user_ns = get_user_ns(user_ns); + new_ns->ucounts = ucounts; + new_ns->root_cset = cset; + + return new_ns; +} + +static inline struct cgroup_namespace *to_cg_ns(struct ns_common *ns) +{ + return container_of(ns, struct cgroup_namespace, ns); +} + +static int cgroupns_install(struct nsproxy *nsproxy, struct ns_common *ns) +{ + struct cgroup_namespace *cgroup_ns = to_cg_ns(ns); + + if (!ns_capable(current_user_ns(), CAP_SYS_ADMIN) || + !ns_capable(cgroup_ns->user_ns, CAP_SYS_ADMIN)) + return -EPERM; + + /* Don't need to do anything if we are attaching to our own cgroupns. */ + if (cgroup_ns == nsproxy->cgroup_ns) + return 0; + + get_cgroup_ns(cgroup_ns); + put_cgroup_ns(nsproxy->cgroup_ns); + nsproxy->cgroup_ns = cgroup_ns; + + return 0; +} + +static struct ns_common *cgroupns_get(struct task_struct *task) +{ + struct cgroup_namespace *ns = NULL; + struct nsproxy *nsproxy; + + task_lock(task); + nsproxy = task->nsproxy; + if (nsproxy) { + ns = nsproxy->cgroup_ns; + get_cgroup_ns(ns); + } + task_unlock(task); + + return ns ? &ns->ns : NULL; +} + +static void cgroupns_put(struct ns_common *ns) +{ + put_cgroup_ns(to_cg_ns(ns)); +} + +static struct user_namespace *cgroupns_owner(struct ns_common *ns) +{ + return to_cg_ns(ns)->user_ns; +} + +const struct proc_ns_operations cgroupns_operations = { + .name = "cgroup", + .type = CLONE_NEWCGROUP, + .get = cgroupns_get, + .put = cgroupns_put, + .install = cgroupns_install, + .owner = cgroupns_owner, +}; + +static __init int cgroup_namespaces_init(void) +{ + return 0; +} +subsys_initcall(cgroup_namespaces_init); diff --git a/kernel/cgroup_pids.c b/kernel/cgroup/pids.c index 2bd673783f1a..2bd673783f1a 100644 --- a/kernel/cgroup_pids.c +++ b/kernel/cgroup/pids.c diff --git a/kernel/cgroup/rdma.c b/kernel/cgroup/rdma.c new file mode 100644 index 000000000000..defad3c5e7dc --- /dev/null +++ b/kernel/cgroup/rdma.c @@ -0,0 +1,619 @@ +/* + * RDMA resource limiting controller for cgroups. + * + * Used to allow a cgroup hierarchy to stop processes from consuming + * additional RDMA resources after a certain limit is reached. + * + * Copyright (C) 2016 Parav Pandit <pandit.parav@gmail.com> + * + * This file is subject to the terms and conditions of version 2 of the GNU + * General Public License. See the file COPYING in the main directory of the + * Linux distribution for more details. + */ + +#include <linux/bitops.h> +#include <linux/slab.h> +#include <linux/seq_file.h> +#include <linux/cgroup.h> +#include <linux/parser.h> +#include <linux/cgroup_rdma.h> + +#define RDMACG_MAX_STR "max" + +/* + * Protects list of resource pools maintained on per cgroup basis + * and rdma device list. + */ +static DEFINE_MUTEX(rdmacg_mutex); +static LIST_HEAD(rdmacg_devices); + +enum rdmacg_file_type { + RDMACG_RESOURCE_TYPE_MAX, + RDMACG_RESOURCE_TYPE_STAT, +}; + +/* + * resource table definition as to be seen by the user. + * Need to add entries to it when more resources are + * added/defined at IB verb/core layer. + */ +static char const *rdmacg_resource_names[] = { + [RDMACG_RESOURCE_HCA_HANDLE] = "hca_handle", + [RDMACG_RESOURCE_HCA_OBJECT] = "hca_object", +}; + +/* resource tracker for each resource of rdma cgroup */ +struct rdmacg_resource { + int max; + int usage; +}; + +/* + * resource pool object which represents per cgroup, per device + * resources. There are multiple instances of this object per cgroup, + * therefore it cannot be embedded within rdma_cgroup structure. It + * is maintained as list. + */ +struct rdmacg_resource_pool { + struct rdmacg_device *device; + struct rdmacg_resource resources[RDMACG_RESOURCE_MAX]; + + struct list_head cg_node; + struct list_head dev_node; + + /* count active user tasks of this pool */ + u64 usage_sum; + /* total number counts which are set to max */ + int num_max_cnt; +}; + +static struct rdma_cgroup *css_rdmacg(struct cgroup_subsys_state *css) +{ + return container_of(css, struct rdma_cgroup, css); +} + +static struct rdma_cgroup *parent_rdmacg(struct rdma_cgroup *cg) +{ + return css_rdmacg(cg->css.parent); +} + +static inline struct rdma_cgroup *get_current_rdmacg(void) +{ + return css_rdmacg(task_get_css(current, rdma_cgrp_id)); +} + +static void set_resource_limit(struct rdmacg_resource_pool *rpool, + int index, int new_max) +{ + if (new_max == S32_MAX) { + if (rpool->resources[index].max != S32_MAX) + rpool->num_max_cnt++; + } else { + if (rpool->resources[index].max == S32_MAX) + rpool->num_max_cnt--; + } + rpool->resources[index].max = new_max; +} + +static void set_all_resource_max_limit(struct rdmacg_resource_pool *rpool) +{ + int i; + + for (i = 0; i < RDMACG_RESOURCE_MAX; i++) + set_resource_limit(rpool, i, S32_MAX); +} + +static void free_cg_rpool_locked(struct rdmacg_resource_pool *rpool) +{ + lockdep_assert_held(&rdmacg_mutex); + + list_del(&rpool->cg_node); + list_del(&rpool->dev_node); + kfree(rpool); +} + +static struct rdmacg_resource_pool * +find_cg_rpool_locked(struct rdma_cgroup *cg, + struct rdmacg_device *device) + +{ + struct rdmacg_resource_pool *pool; + + lockdep_assert_held(&rdmacg_mutex); + + list_for_each_entry(pool, &cg->rpools, cg_node) + if (pool->device == device) + return pool; + + return NULL; +} + +static struct rdmacg_resource_pool * +get_cg_rpool_locked(struct rdma_cgroup *cg, struct rdmacg_device *device) +{ + struct rdmacg_resource_pool *rpool; + + rpool = find_cg_rpool_locked(cg, device); + if (rpool) + return rpool; + + rpool = kzalloc(sizeof(*rpool), GFP_KERNEL); + if (!rpool) + return ERR_PTR(-ENOMEM); + + rpool->device = device; + set_all_resource_max_limit(rpool); + + INIT_LIST_HEAD(&rpool->cg_node); + INIT_LIST_HEAD(&rpool->dev_node); + list_add_tail(&rpool->cg_node, &cg->rpools); + list_add_tail(&rpool->dev_node, &device->rpools); + return rpool; +} + +/** + * uncharge_cg_locked - uncharge resource for rdma cgroup + * @cg: pointer to cg to uncharge and all parents in hierarchy + * @device: pointer to rdmacg device + * @index: index of the resource to uncharge in cg (resource pool) + * + * It also frees the resource pool which was created as part of + * charging operation when there are no resources attached to + * resource pool. + */ +static void +uncharge_cg_locked(struct rdma_cgroup *cg, + struct rdmacg_device *device, + enum rdmacg_resource_type index) +{ + struct rdmacg_resource_pool *rpool; + + rpool = find_cg_rpool_locked(cg, device); + + /* + * rpool cannot be null at this stage. Let kernel operate in case + * if there a bug in IB stack or rdma controller, instead of crashing + * the system. + */ + if (unlikely(!rpool)) { + pr_warn("Invalid device %p or rdma cgroup %p\n", cg, device); + return; + } + + rpool->resources[index].usage--; + + /* + * A negative count (or overflow) is invalid, + * it indicates a bug in the rdma controller. + */ + WARN_ON_ONCE(rpool->resources[index].usage < 0); + rpool->usage_sum--; + if (rpool->usage_sum == 0 && + rpool->num_max_cnt == RDMACG_RESOURCE_MAX) { + /* + * No user of the rpool and all entries are set to max, so + * safe to delete this rpool. + */ + free_cg_rpool_locked(rpool); + } +} + +/** + * rdmacg_uncharge_hierarchy - hierarchically uncharge rdma resource count + * @device: pointer to rdmacg device + * @stop_cg: while traversing hirerchy, when meet with stop_cg cgroup + * stop uncharging + * @index: index of the resource to uncharge in cg in given resource pool + */ +static void rdmacg_uncharge_hierarchy(struct rdma_cgroup *cg, + struct rdmacg_device *device, + struct rdma_cgroup *stop_cg, + enum rdmacg_resource_type index) +{ + struct rdma_cgroup *p; + + mutex_lock(&rdmacg_mutex); + + for (p = cg; p != stop_cg; p = parent_rdmacg(p)) + uncharge_cg_locked(p, device, index); + + mutex_unlock(&rdmacg_mutex); + + css_put(&cg->css); +} + +/** + * rdmacg_uncharge - hierarchically uncharge rdma resource count + * @device: pointer to rdmacg device + * @index: index of the resource to uncharge in cgroup in given resource pool + */ +void rdmacg_uncharge(struct rdma_cgroup *cg, + struct rdmacg_device *device, + enum rdmacg_resource_type index) +{ + if (index >= RDMACG_RESOURCE_MAX) + return; + + rdmacg_uncharge_hierarchy(cg, device, NULL, index); +} +EXPORT_SYMBOL(rdmacg_uncharge); + +/** + * rdmacg_try_charge - hierarchically try to charge the rdma resource + * @rdmacg: pointer to rdma cgroup which will own this resource + * @device: pointer to rdmacg device + * @index: index of the resource to charge in cgroup (resource pool) + * + * This function follows charging resource in hierarchical way. + * It will fail if the charge would cause the new value to exceed the + * hierarchical limit. + * Returns 0 if the charge succeded, otherwise -EAGAIN, -ENOMEM or -EINVAL. + * Returns pointer to rdmacg for this resource when charging is successful. + * + * Charger needs to account resources on two criteria. + * (a) per cgroup & (b) per device resource usage. + * Per cgroup resource usage ensures that tasks of cgroup doesn't cross + * the configured limits. Per device provides granular configuration + * in multi device usage. It allocates resource pool in the hierarchy + * for each parent it come across for first resource. Later on resource + * pool will be available. Therefore it will be much faster thereon + * to charge/uncharge. + */ +int rdmacg_try_charge(struct rdma_cgroup **rdmacg, + struct rdmacg_device *device, + enum rdmacg_resource_type index) +{ + struct rdma_cgroup *cg, *p; + struct rdmacg_resource_pool *rpool; + s64 new; + int ret = 0; + + if (index >= RDMACG_RESOURCE_MAX) + return -EINVAL; + + /* + * hold on to css, as cgroup can be removed but resource + * accounting happens on css. + */ + cg = get_current_rdmacg(); + + mutex_lock(&rdmacg_mutex); + for (p = cg; p; p = parent_rdmacg(p)) { + rpool = get_cg_rpool_locked(p, device); + if (IS_ERR(rpool)) { + ret = PTR_ERR(rpool); + goto err; + } else { + new = rpool->resources[index].usage + 1; + if (new > rpool->resources[index].max) { + ret = -EAGAIN; + goto err; + } else { + rpool->resources[index].usage = new; + rpool->usage_sum++; + } + } + } + mutex_unlock(&rdmacg_mutex); + + *rdmacg = cg; + return 0; + +err: + mutex_unlock(&rdmacg_mutex); + rdmacg_uncharge_hierarchy(cg, device, p, index); + return ret; +} +EXPORT_SYMBOL(rdmacg_try_charge); + +/** + * rdmacg_register_device - register rdmacg device to rdma controller. + * @device: pointer to rdmacg device whose resources need to be accounted. + * + * If IB stack wish a device to participate in rdma cgroup resource + * tracking, it must invoke this API to register with rdma cgroup before + * any user space application can start using the RDMA resources. + * Returns 0 on success or EINVAL when table length given is beyond + * supported size. + */ +int rdmacg_register_device(struct rdmacg_device *device) +{ + INIT_LIST_HEAD(&device->dev_node); + INIT_LIST_HEAD(&device->rpools); + + mutex_lock(&rdmacg_mutex); + list_add_tail(&device->dev_node, &rdmacg_devices); + mutex_unlock(&rdmacg_mutex); + return 0; +} +EXPORT_SYMBOL(rdmacg_register_device); + +/** + * rdmacg_unregister_device - unregister rdmacg device from rdma controller. + * @device: pointer to rdmacg device which was previously registered with rdma + * controller using rdmacg_register_device(). + * + * IB stack must invoke this after all the resources of the IB device + * are destroyed and after ensuring that no more resources will be created + * when this API is invoked. + */ +void rdmacg_unregister_device(struct rdmacg_device *device) +{ + struct rdmacg_resource_pool *rpool, *tmp; + + /* + * Synchronize with any active resource settings, + * usage query happening via configfs. + */ + mutex_lock(&rdmacg_mutex); + list_del_init(&device->dev_node); + + /* + * Now that this device is off the cgroup list, its safe to free + * all the rpool resources. + */ + list_for_each_entry_safe(rpool, tmp, &device->rpools, dev_node) + free_cg_rpool_locked(rpool); + + mutex_unlock(&rdmacg_mutex); +} +EXPORT_SYMBOL(rdmacg_unregister_device); + +static int parse_resource(char *c, int *intval) +{ + substring_t argstr; + const char **table = &rdmacg_resource_names[0]; + char *name, *value = c; + size_t len; + int ret, i = 0; + + name = strsep(&value, "="); + if (!name || !value) + return -EINVAL; + + len = strlen(value); + + for (i = 0; i < RDMACG_RESOURCE_MAX; i++) { + if (strcmp(table[i], name)) + continue; + + argstr.from = value; + argstr.to = value + len; + + ret = match_int(&argstr, intval); + if (ret >= 0) { + if (*intval < 0) + break; + return i; + } + if (strncmp(value, RDMACG_MAX_STR, len) == 0) { + *intval = S32_MAX; + return i; + } + break; + } + return -EINVAL; +} + +static int rdmacg_parse_limits(char *options, + int *new_limits, unsigned long *enables) +{ + char *c; + int err = -EINVAL; + + /* parse resource options */ + while ((c = strsep(&options, " ")) != NULL) { + int index, intval; + + index = parse_resource(c, &intval); + if (index < 0) + goto err; + + new_limits[index] = intval; + *enables |= BIT(index); + } + return 0; + +err: + return err; +} + +static struct rdmacg_device *rdmacg_get_device_locked(const char *name) +{ + struct rdmacg_device *device; + + lockdep_assert_held(&rdmacg_mutex); + + list_for_each_entry(device, &rdmacg_devices, dev_node) + if (!strcmp(name, device->name)) + return device; + + return NULL; +} + +static ssize_t rdmacg_resource_set_max(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct rdma_cgroup *cg = css_rdmacg(of_css(of)); + const char *dev_name; + struct rdmacg_resource_pool *rpool; + struct rdmacg_device *device; + char *options = strstrip(buf); + int *new_limits; + unsigned long enables = 0; + int i = 0, ret = 0; + + /* extract the device name first */ + dev_name = strsep(&options, " "); + if (!dev_name) { + ret = -EINVAL; + goto err; + } + + new_limits = kcalloc(RDMACG_RESOURCE_MAX, sizeof(int), GFP_KERNEL); + if (!new_limits) { + ret = -ENOMEM; + goto err; + } + + ret = rdmacg_parse_limits(options, new_limits, &enables); + if (ret) + goto parse_err; + + /* acquire lock to synchronize with hot plug devices */ + mutex_lock(&rdmacg_mutex); + + device = rdmacg_get_device_locked(dev_name); + if (!device) { + ret = -ENODEV; + goto dev_err; + } + + rpool = get_cg_rpool_locked(cg, device); + if (IS_ERR(rpool)) { + ret = PTR_ERR(rpool); + goto dev_err; + } + + /* now set the new limits of the rpool */ + for_each_set_bit(i, &enables, RDMACG_RESOURCE_MAX) + set_resource_limit(rpool, i, new_limits[i]); + + if (rpool->usage_sum == 0 && + rpool->num_max_cnt == RDMACG_RESOURCE_MAX) { + /* + * No user of the rpool and all entries are set to max, so + * safe to delete this rpool. + */ + free_cg_rpool_locked(rpool); + } + +dev_err: + mutex_unlock(&rdmacg_mutex); + +parse_err: + kfree(new_limits); + +err: + return ret ?: nbytes; +} + +static void print_rpool_values(struct seq_file *sf, + struct rdmacg_resource_pool *rpool) +{ + enum rdmacg_file_type sf_type; + int i; + u32 value; + + sf_type = seq_cft(sf)->private; + + for (i = 0; i < RDMACG_RESOURCE_MAX; i++) { + seq_puts(sf, rdmacg_resource_names[i]); + seq_putc(sf, '='); + if (sf_type == RDMACG_RESOURCE_TYPE_MAX) { + if (rpool) + value = rpool->resources[i].max; + else + value = S32_MAX; + } else { + if (rpool) + value = rpool->resources[i].usage; + else + value = 0; + } + + if (value == S32_MAX) + seq_puts(sf, RDMACG_MAX_STR); + else + seq_printf(sf, "%d", value); + seq_putc(sf, ' '); + } +} + +static int rdmacg_resource_read(struct seq_file *sf, void *v) +{ + struct rdmacg_device *device; + struct rdmacg_resource_pool *rpool; + struct rdma_cgroup *cg = css_rdmacg(seq_css(sf)); + + mutex_lock(&rdmacg_mutex); + + list_for_each_entry(device, &rdmacg_devices, dev_node) { + seq_printf(sf, "%s ", device->name); + + rpool = find_cg_rpool_locked(cg, device); + print_rpool_values(sf, rpool); + + seq_putc(sf, '\n'); + } + + mutex_unlock(&rdmacg_mutex); + return 0; +} + +static struct cftype rdmacg_files[] = { + { + .name = "max", + .write = rdmacg_resource_set_max, + .seq_show = rdmacg_resource_read, + .private = RDMACG_RESOURCE_TYPE_MAX, + .flags = CFTYPE_NOT_ON_ROOT, + }, + { + .name = "current", + .seq_show = rdmacg_resource_read, + .private = RDMACG_RESOURCE_TYPE_STAT, + .flags = CFTYPE_NOT_ON_ROOT, + }, + { } /* terminate */ +}; + +static struct cgroup_subsys_state * +rdmacg_css_alloc(struct cgroup_subsys_state *parent) +{ + struct rdma_cgroup *cg; + + cg = kzalloc(sizeof(*cg), GFP_KERNEL); + if (!cg) + return ERR_PTR(-ENOMEM); + + INIT_LIST_HEAD(&cg->rpools); + return &cg->css; +} + +static void rdmacg_css_free(struct cgroup_subsys_state *css) +{ + struct rdma_cgroup *cg = css_rdmacg(css); + + kfree(cg); +} + +/** + * rdmacg_css_offline - cgroup css_offline callback + * @css: css of interest + * + * This function is called when @css is about to go away and responsible + * for shooting down all rdmacg associated with @css. As part of that it + * marks all the resource pool entries to max value, so that when resources are + * uncharged, associated resource pool can be freed as well. + */ +static void rdmacg_css_offline(struct cgroup_subsys_state *css) +{ + struct rdma_cgroup *cg = css_rdmacg(css); + struct rdmacg_resource_pool *rpool; + + mutex_lock(&rdmacg_mutex); + + list_for_each_entry(rpool, &cg->rpools, cg_node) + set_all_resource_max_limit(rpool); + + mutex_unlock(&rdmacg_mutex); +} + +struct cgroup_subsys rdma_cgrp_subsys = { + .css_alloc = rdmacg_css_alloc, + .css_free = rdmacg_css_free, + .css_offline = rdmacg_css_offline, + .legacy_cftypes = rdmacg_files, + .dfl_cftypes = rdmacg_files, +}; diff --git a/kernel/events/core.c b/kernel/events/core.c index b2eb3542e829..5b4e0b98f4eb 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -10959,5 +10959,11 @@ struct cgroup_subsys perf_event_cgrp_subsys = { .css_alloc = perf_cgroup_css_alloc, .css_free = perf_cgroup_css_free, .attach = perf_cgroup_attach, + /* + * Implicitly enable on dfl hierarchy so that perf events can + * always be filtered by cgroup2 path as long as perf_event + * controller is not mounted on a legacy hierarchy. + */ + .implicit_on_dfl = true, }; #endif /* CONFIG_CGROUP_PERF */ |