/* * Generic process-grouping system. * * Based originally on the cpuset system, extracted by Paul Menage * Copyright (C) 2006 Google, Inc * * Notifications support * Copyright (C) 2009 Nokia Corporation * Author: Kirill A. Shutemov * * Copyright notices from the original cpuset code: * -------------------------------------------------- * Copyright (C) 2003 BULL SA. * Copyright (C) 2004-2006 Silicon Graphics, Inc. * * Portions derived from Patrick Mochel's sysfs code. * sysfs is Copyright (c) 2001-3 Patrick Mochel * * 2003-10-10 Written by Simon Derr. * 2003-10-22 Updates by Stephen Hemminger. * 2004 May-July Rework by Paul Jackson. * --------------------------------------------------- * * This file is subject to the terms and conditions of the GNU General Public * License. See the file COPYING in the main directory of the Linux * distribution for more details. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static DEFINE_MUTEX(cgroup_mutex); static DEFINE_MUTEX(cgroup_root_mutex); #define SUBSYS(_x) &_x ## _subsys, static struct cgroup_subsys *subsys[CGROUP_SUBSYS_COUNT] = { #include }; #define MAX_CGROUP_ROOT_NAMELEN 64 struct cgroupfs_root { struct super_block *sb; unsigned long subsys_bits; int hierarchy_id; unsigned long actual_subsys_bits; struct list_head subsys_list; struct cgroup top_cgroup; int number_of_cgroups; struct list_head root_list; unsigned long flags; char release_agent_path[PATH_MAX]; char name[MAX_CGROUP_ROOT_NAMELEN]; }; static struct cgroupfs_root rootnode; #define CSS_ID_MAX (65535) struct css_id { struct cgroup_subsys_state __rcu *css; unsigned short id; unsigned short depth; struct rcu_head rcu_head; unsigned short stack[0]; }; struct cgroup_event { struct cgroup *cgrp; struct cftype *cft; struct eventfd_ctx *eventfd; struct list_head list; poll_table pt; wait_queue_head_t *wqh; wait_queue_t wait; struct work_struct remove; }; static LIST_HEAD(roots); static int root_count; static DEFINE_IDA(hierarchy_ida); static int next_hierarchy_id; static DEFINE_SPINLOCK(hierarchy_id_lock); #define dummytop (&rootnode.top_cgroup) static int need_forkexit_callback __read_mostly; #ifdef CONFIG_PROVE_LOCKING int cgroup_lock_is_held(void) { return lockdep_is_held(&cgroup_mutex); } #else int cgroup_lock_is_held(void) { return mutex_is_locked(&cgroup_mutex); } #endif EXPORT_SYMBOL_GPL(cgroup_lock_is_held); inline int cgroup_is_removed(const struct cgroup *cgrp) { return test_bit(CGRP_REMOVED, &cgrp->flags); } enum { ROOT_NOPREFIX, }; static int cgroup_is_releasable(const struct cgroup *cgrp) { const int bits = (1 << CGRP_RELEASABLE) | (1 << CGRP_NOTIFY_ON_RELEASE); return (cgrp->flags & bits) == bits; } static int notify_on_release(const struct cgroup *cgrp) { return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); } static int clone_children(const struct cgroup *cgrp) { return test_bit(CGRP_CLONE_CHILDREN, &cgrp->flags); } #define for_each_subsys(_root, _ss) \ list_for_each_entry(_ss, &_root->subsys_list, sibling) #define for_each_active_root(_root) \ list_for_each_entry(_root, &roots, root_list) static LIST_HEAD(release_list); static DEFINE_RAW_SPINLOCK(release_list_lock); static void cgroup_release_agent(struct work_struct *work); static DECLARE_WORK(release_agent_work, cgroup_release_agent); static void check_for_release(struct cgroup *cgrp); static DECLARE_WAIT_QUEUE_HEAD(cgroup_rmdir_waitq); static void cgroup_wakeup_rmdir_waiter(struct cgroup *cgrp) { if (unlikely(test_and_clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags))) wake_up_all(&cgroup_rmdir_waitq); } void cgroup_exclude_rmdir(struct cgroup_subsys_state *css) { css_get(css); } void cgroup_release_and_wakeup_rmdir(struct cgroup_subsys_state *css) { cgroup_wakeup_rmdir_waiter(css->cgroup); css_put(css); } struct cg_cgroup_link { struct list_head cgrp_link_list; struct cgroup *cgrp; struct list_head cg_link_list; struct css_set *cg; }; static struct css_set init_css_set; static struct cg_cgroup_link init_css_set_link; static int cgroup_init_idr(struct cgroup_subsys *ss, struct cgroup_subsys_state *css); static DEFINE_RWLOCK(css_set_lock); static int css_set_count; #define CSS_SET_HASH_BITS 7 #define CSS_SET_TABLE_SIZE (1 << CSS_SET_HASH_BITS) static struct hlist_head css_set_table[CSS_SET_TABLE_SIZE]; static struct hlist_head *css_set_hash(struct cgroup_subsys_state *css[]) { int i; int index; unsigned long tmp = 0UL; for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) tmp += (unsigned long)css[i]; tmp = (tmp >> 16) ^ tmp; index = hash_long(tmp, CSS_SET_HASH_BITS); return &css_set_table[index]; } static void free_css_set_work(struct work_struct *work) { struct css_set *cg = container_of(work, struct css_set, work); struct cg_cgroup_link *link; struct cg_cgroup_link *saved_link; write_lock(&css_set_lock); list_for_each_entry_safe(link, saved_link, &cg->cg_links, cg_link_list) { struct cgroup *cgrp = link->cgrp; list_del(&link->cg_link_list); list_del(&link->cgrp_link_list); if (atomic_dec_and_test(&cgrp->count)) { check_for_release(cgrp); cgroup_wakeup_rmdir_waiter(cgrp); } kfree(link); } write_unlock(&css_set_lock); kfree(cg); } static void free_css_set_rcu(struct rcu_head *obj) { struct css_set *cg = container_of(obj, struct css_set, rcu_head); INIT_WORK(&cg->work, free_css_set_work); schedule_work(&cg->work); } static int use_task_css_set_links __read_mostly; static inline void get_css_set(struct css_set *cg) { atomic_inc(&cg->refcount); } static void put_css_set(struct css_set *cg) { if (atomic_add_unless(&cg->refcount, -1, 1)) return; write_lock(&css_set_lock); if (!atomic_dec_and_test(&cg->refcount)) { write_unlock(&css_set_lock); return; } hlist_del(&cg->hlist); css_set_count--; write_unlock(&css_set_lock); call_rcu(&cg->rcu_head, free_css_set_rcu); } static bool compare_css_sets(struct css_set *cg, struct css_set *old_cg, struct cgroup *new_cgrp, struct cgroup_subsys_state *template[]) { struct list_head *l1, *l2; if (memcmp(template, cg->subsys, sizeof(cg->subsys))) { return false; } l1 = &cg->cg_links; l2 = &old_cg->cg_links; while (1) { struct cg_cgroup_link *cgl1, *cgl2; struct cgroup *cg1, *cg2; l1 = l1->next; l2 = l2->next; if (l1 == &cg->cg_links) { BUG_ON(l2 != &old_cg->cg_links); break; } else { BUG_ON(l2 == &old_cg->cg_links); } cgl1 = list_entry(l1, struct cg_cgroup_link, cg_link_list); cgl2 = list_entry(l2, struct cg_cgroup_link, cg_link_list); cg1 = cgl1->cgrp; cg2 = cgl2->cgrp; BUG_ON(cg1->root != cg2->root); if (cg1->root == new_cgrp->root) { if (cg1 != new_cgrp) return false; } else { if (cg1 != cg2) return false; } } return true; } static struct css_set *find_existing_css_set( struct css_set *oldcg, struct cgroup *cgrp, struct cgroup_subsys_state *template[]) { int i; struct cgroupfs_root *root = cgrp->root; struct hlist_head *hhead; struct hlist_node *node; struct css_set *cg; for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { if (root->subsys_bits & (1UL << i)) { template[i] = cgrp->subsys[i]; } else { template[i] = oldcg->subsys[i]; } } hhead = css_set_hash(template); hlist_for_each_entry(cg, node, hhead, hlist) { if (!compare_css_sets(cg, oldcg, cgrp, template)) continue; return cg; } return NULL; } static void free_cg_links(struct list_head *tmp) { struct cg_cgroup_link *link; struct cg_cgroup_link *saved_link; list_for_each_entry_safe(link, saved_link, tmp, cgrp_link_list) { list_del(&link->cgrp_link_list); kfree(link); } } static int allocate_cg_links(int count, struct list_head *tmp) { struct cg_cgroup_link *link; int i; INIT_LIST_HEAD(tmp); for (i = 0; i < count; i++) { link = kmalloc(sizeof(*link), GFP_KERNEL); if (!link) { free_cg_links(tmp); return -ENOMEM; } list_add(&link->cgrp_link_list, tmp); } return 0; } static void link_css_set(struct list_head *tmp_cg_links, struct css_set *cg, struct cgroup *cgrp) { struct cg_cgroup_link *link; BUG_ON(list_empty(tmp_cg_links)); link = list_first_entry(tmp_cg_links, struct cg_cgroup_link, cgrp_link_list); link->cg = cg; link->cgrp = cgrp; atomic_inc(&cgrp->count); list_move(&link->cgrp_link_list, &cgrp->css_sets); list_add_tail(&link->cg_link_list, &cg->cg_links); } static struct css_set *find_css_set( struct css_set *oldcg, struct cgroup *cgrp) { struct css_set *res; struct cgroup_subsys_state *template[CGROUP_SUBSYS_COUNT]; struct list_head tmp_cg_links; struct hlist_head *hhead; struct cg_cgroup_link *link; read_lock(&css_set_lock); res = find_existing_css_set(oldcg, cgrp, template); if (res) get_css_set(res); read_unlock(&css_set_lock); if (res) return res; res = kmalloc(sizeof(*res), GFP_KERNEL); if (!res) return NULL; if (allocate_cg_links(root_count, &tmp_cg_links) < 0) { kfree(res); return NULL; } atomic_set(&res->refcount, 1); INIT_LIST_HEAD(&res->cg_links); INIT_LIST_HEAD(&res->tasks); INIT_HLIST_NODE(&res->hlist); memcpy(res->subsys, template, sizeof(res->subsys)); write_lock(&css_set_lock); list_for_each_entry(link, &oldcg->cg_links, cg_link_list) { struct cgroup *c = link->cgrp; if (c->root == cgrp->root) c = cgrp; link_css_set(&tmp_cg_links, res, c); } BUG_ON(!list_empty(&tmp_cg_links)); css_set_count++; hhead = css_set_hash(res->subsys); hlist_add_head(&res->hlist, hhead); write_unlock(&css_set_lock); return res; } static struct cgroup *task_cgroup_from_root(struct task_struct *task, struct cgroupfs_root *root) { struct css_set *css; struct cgroup *res = NULL; BUG_ON(!mutex_is_locked(&cgroup_mutex)); read_lock(&css_set_lock); css = task->cgroups; if (css == &init_css_set) { res = &root->top_cgroup; } else { struct cg_cgroup_link *link; list_for_each_entry(link, &css->cg_links, cg_link_list) { struct cgroup *c = link->cgrp; if (c->root == root) { res = c; break; } } } read_unlock(&css_set_lock); BUG_ON(!res); return res; } void cgroup_lock(void) { mutex_lock(&cgroup_mutex); } EXPORT_SYMBOL_GPL(cgroup_lock); void cgroup_unlock(void) { mutex_unlock(&cgroup_mutex); } EXPORT_SYMBOL_GPL(cgroup_unlock); static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode); static struct dentry *cgroup_lookup(struct inode *, struct dentry *, struct nameidata *); static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry); static int cgroup_populate_dir(struct cgroup *cgrp); static const struct inode_operations cgroup_dir_inode_operations; static const struct file_operations proc_cgroupstats_operations; static struct backing_dev_info cgroup_backing_dev_info = { .name = "cgroup", .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, }; static int alloc_css_id(struct cgroup_subsys *ss, struct cgroup *parent, struct cgroup *child); static struct inode *cgroup_new_inode(umode_t mode, struct super_block *sb) { struct inode *inode = new_inode(sb); if (inode) { inode->i_ino = get_next_ino(); inode->i_mode = mode; inode->i_uid = current_fsuid(); inode->i_gid = current_fsgid(); inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; inode->i_mapping->backing_dev_info = &cgroup_backing_dev_info; } return inode; } static int cgroup_call_pre_destroy(struct cgroup *cgrp) { struct cgroup_subsys *ss; int ret = 0; for_each_subsys(cgrp->root, ss) if (ss->pre_destroy) { ret = ss->pre_destroy(cgrp); if (ret) break; } return ret; } static void cgroup_diput(struct dentry *dentry, struct inode *inode) { if (S_ISDIR(inode->i_mode)) { struct cgroup *cgrp = dentry->d_fsdata; struct cgroup_subsys *ss; BUG_ON(!(cgroup_is_removed(cgrp))); synchronize_rcu(); mutex_lock(&cgroup_mutex); for_each_subsys(cgrp->root, ss) ss->destroy(cgrp); cgrp->root->number_of_cgroups--; mutex_unlock(&cgroup_mutex); deactivate_super(cgrp->root->sb); BUG_ON(!list_empty(&cgrp->pidlists)); kfree_rcu(cgrp, rcu_head); } iput(inode); } static int cgroup_delete(const struct dentry *d) { return 1; } static void remove_dir(struct dentry *d) { struct dentry *parent = dget(d->d_parent); d_delete(d); simple_rmdir(parent->d_inode, d); dput(parent); } static void cgroup_clear_directory(struct dentry *dentry) { struct list_head *node; BUG_ON(!mutex_is_locked(&dentry->d_inode->i_mutex)); spin_lock(&dentry->d_lock); node = dentry->d_subdirs.next; while (node != &dentry->d_subdirs) { struct dentry *d = list_entry(node, struct dentry, d_u.d_child); spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED); list_del_init(node); if (d->d_inode) { BUG_ON(d->d_inode->i_mode & S_IFDIR); dget_dlock(d); spin_unlock(&d->d_lock); spin_unlock(&dentry->d_lock); d_delete(d); simple_unlink(dentry->d_inode, d); dput(d); spin_lock(&dentry->d_lock); } else spin_unlock(&d->d_lock); node = dentry->d_subdirs.next; } spin_unlock(&dentry->d_lock); } static void cgroup_d_remove_dir(struct dentry *dentry) { struct dentry *parent; cgroup_clear_directory(dentry); parent = dentry->d_parent; spin_lock(&parent->d_lock); spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); list_del_init(&dentry->d_u.d_child); spin_unlock(&dentry->d_lock); spin_unlock(&parent->d_lock); remove_dir(dentry); } static int rebind_subsystems(struct cgroupfs_root *root, unsigned long final_bits) { unsigned long added_bits, removed_bits; struct cgroup *cgrp = &root->top_cgroup; int i; BUG_ON(!mutex_is_locked(&cgroup_mutex)); BUG_ON(!mutex_is_locked(&cgroup_root_mutex)); removed_bits = root->actual_subsys_bits & ~final_bits; added_bits = final_bits & ~root->actual_subsys_bits; for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { unsigned long bit = 1UL << i; struct cgroup_subsys *ss = subsys[i]; if (!(bit & added_bits)) continue; BUG_ON(ss == NULL); if (ss->root != &rootnode) { return -EBUSY; } } if (root->number_of_cgroups > 1) return -EBUSY; for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; unsigned long bit = 1UL << i; if (bit & added_bits) { BUG_ON(ss == NULL); BUG_ON(cgrp->subsys[i]); BUG_ON(!dummytop->subsys[i]); BUG_ON(dummytop->subsys[i]->cgroup != dummytop); mutex_lock(&ss->hierarchy_mutex); cgrp->subsys[i] = dummytop->subsys[i]; cgrp->subsys[i]->cgroup = cgrp; list_move(&ss->sibling, &root->subsys_list); ss->root = root; if (ss->bind) ss->bind(cgrp); mutex_unlock(&ss->hierarchy_mutex); } else if (bit & removed_bits) { BUG_ON(ss == NULL); BUG_ON(cgrp->subsys[i] != dummytop->subsys[i]); BUG_ON(cgrp->subsys[i]->cgroup != cgrp); mutex_lock(&ss->hierarchy_mutex); if (ss->bind) ss->bind(dummytop); dummytop->subsys[i]->cgroup = dummytop; cgrp->subsys[i] = NULL; subsys[i]->root = &rootnode; list_move(&ss->sibling, &rootnode.subsys_list); mutex_unlock(&ss->hierarchy_mutex); module_put(ss->module); } else if (bit & final_bits) { BUG_ON(ss == NULL); BUG_ON(!cgrp->subsys[i]); module_put(ss->module); #ifdef CONFIG_MODULE_UNLOAD BUG_ON(ss->module && !module_refcount(ss->module)); #endif } else { BUG_ON(cgrp->subsys[i]); } } root->subsys_bits = root->actual_subsys_bits = final_bits; synchronize_rcu(); return 0; } static int cgroup_show_options(struct seq_file *seq, struct dentry *dentry) { struct cgroupfs_root *root = dentry->d_sb->s_fs_info; struct cgroup_subsys *ss; mutex_lock(&cgroup_root_mutex); for_each_subsys(root, ss) seq_printf(seq, ",%s", ss->name); if (test_bit(ROOT_NOPREFIX, &root->flags)) seq_puts(seq, ",noprefix"); if (strlen(root->release_agent_path)) seq_printf(seq, ",release_agent=%s", root->release_agent_path); if (clone_children(&root->top_cgroup)) seq_puts(seq, ",clone_children"); if (strlen(root->name)) seq_printf(seq, ",name=%s", root->name); mutex_unlock(&cgroup_root_mutex); return 0; } struct cgroup_sb_opts { unsigned long subsys_bits; unsigned long flags; char *release_agent; bool clone_children; char *name; bool none; struct cgroupfs_root *new_root; }; static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) { char *token, *o = data; bool all_ss = false, one_ss = false; unsigned long mask = (unsigned long)-1; int i; bool module_pin_failed = false; BUG_ON(!mutex_is_locked(&cgroup_mutex)); #ifdef CONFIG_CPUSETS mask = ~(1UL << cpuset_subsys_id); #endif memset(opts, 0, sizeof(*opts)); while ((token = strsep(&o, ",")) != NULL) { if (!*token) return -EINVAL; if (!strcmp(token, "none")) { opts->none = true; continue; } if (!strcmp(token, "all")) { if (one_ss) return -EINVAL; all_ss = true; continue; } if (!strcmp(token, "noprefix")) { set_bit(ROOT_NOPREFIX, &opts->flags); continue; } if (!strcmp(token, "clone_children")) { opts->clone_children = true; continue; } if (!strncmp(token, "release_agent=", 14)) { 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; if (!strlen(name)) return -EINVAL; for (i = 0; i < strlen(name); i++) { char c = name[i]; if (isalnum(c)) continue; if ((c == '.') || (c == '-') || (c == '_')) continue; return -EINVAL; } if (opts->name) return -EINVAL; opts->name = kstrndup(name, MAX_CGROUP_ROOT_NAMELEN - 1, GFP_KERNEL); if (!opts->name) return -ENOMEM; continue; } for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; if (ss == NULL) continue; if (strcmp(token, ss->name)) continue; if (ss->disabled) continue; if (all_ss) return -EINVAL; set_bit(i, &opts->subsys_bits); one_ss = true; break; } if (i == CGROUP_SUBSYS_COUNT) return -ENOENT; } if (all_ss || (!one_ss && !opts->none && !opts->name)) { for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; if (ss == NULL) continue; if (ss->disabled) continue; set_bit(i, &opts->subsys_bits); } } if (test_bit(ROOT_NOPREFIX, &opts->flags) && (opts->subsys_bits & mask)) return -EINVAL; if (opts->subsys_bits && opts->none) return -EINVAL; if (!opts->subsys_bits && !opts->name) return -EINVAL; for (i = CGROUP_BUILTIN_SUBSYS_COUNT; i < CGROUP_SUBSYS_COUNT; i++) { unsigned long bit = 1UL << i; if (!(bit & opts->subsys_bits)) continue; if (!try_module_get(subsys[i]->module)) { module_pin_failed = true; break; } } if (module_pin_failed) { for (i--; i >= CGROUP_BUILTIN_SUBSYS_COUNT; i--) { unsigned long bit = 1UL << i; if (!(bit & opts->subsys_bits)) continue; module_put(subsys[i]->module); } return -ENOENT; } return 0; } static void drop_parsed_module_refcounts(unsigned long subsys_bits) { int i; for (i = CGROUP_BUILTIN_SUBSYS_COUNT; i < CGROUP_SUBSYS_COUNT; i++) { unsigned long bit = 1UL << i; if (!(bit & subsys_bits)) continue; module_put(subsys[i]->module); } } static int cgroup_remount(struct super_block *sb, int *flags, char *data) { int ret = 0; struct cgroupfs_root *root = sb->s_fs_info; struct cgroup *cgrp = &root->top_cgroup; struct cgroup_sb_opts opts; mutex_lock(&cgrp->dentry->d_inode->i_mutex); mutex_lock(&cgroup_mutex); mutex_lock(&cgroup_root_mutex); ret = parse_cgroupfs_options(data, &opts); if (ret) goto out_unlock; if (opts.flags != root->flags || (opts.name && strcmp(opts.name, root->name))) { ret = -EINVAL; drop_parsed_module_refcounts(opts.subsys_bits); goto out_unlock; } ret = rebind_subsystems(root, opts.subsys_bits); if (ret) { drop_parsed_module_refcounts(opts.subsys_bits); goto out_unlock; } cgroup_populate_dir(cgrp); if (opts.release_agent) strcpy(root->release_agent_path, opts.release_agent); out_unlock: kfree(opts.release_agent); kfree(opts.name); mutex_unlock(&cgroup_root_mutex); mutex_unlock(&cgroup_mutex); mutex_unlock(&cgrp->dentry->d_inode->i_mutex); return ret; } static const struct super_operations cgroup_ops = { .statfs = simple_statfs, .drop_inode = generic_delete_inode, .show_options = cgroup_show_options, .remount_fs = cgroup_remount, }; static void init_cgroup_housekeeping(struct cgroup *cgrp) { INIT_LIST_HEAD(&cgrp->sibling); INIT_LIST_HEAD(&cgrp->children); INIT_LIST_HEAD(&cgrp->css_sets); INIT_LIST_HEAD(&cgrp->release_list); INIT_LIST_HEAD(&cgrp->pidlists); mutex_init(&cgrp->pidlist_mutex); INIT_LIST_HEAD(&cgrp->event_list); spin_lock_init(&cgrp->event_list_lock); } static void init_cgroup_root(struct cgroupfs_root *root) { struct cgroup *cgrp = &root->top_cgroup; INIT_LIST_HEAD(&root->subsys_list); INIT_LIST_HEAD(&root->root_list); root->number_of_cgroups = 1; cgrp->root = root; cgrp->top_cgroup = cgrp; init_cgroup_housekeeping(cgrp); } static bool init_root_id(struct cgroupfs_root *root) { int ret = 0; do { if (!ida_pre_get(&hierarchy_ida, GFP_KERNEL)) return false; spin_lock(&hierarchy_id_lock); ret = ida_get_new_above(&hierarchy_ida, next_hierarchy_id, &root->hierarchy_id); if (ret == -ENOSPC) ret = ida_get_new(&hierarchy_ida, &root->hierarchy_id); if (!ret) { next_hierarchy_id = root->hierarchy_id + 1; } else if (ret != -EAGAIN) { BUG_ON(ret); } spin_unlock(&hierarchy_id_lock); } while (ret); return true; } static int cgroup_test_super(struct super_block *sb, void *data) { struct cgroup_sb_opts *opts = data; struct cgroupfs_root *root = sb->s_fs_info; if (opts->name && strcmp(opts->name, root->name)) return 0; if ((opts->subsys_bits || opts->none) && (opts->subsys_bits != root->subsys_bits)) return 0; return 1; } static struct cgroupfs_root *cgroup_root_from_opts(struct cgroup_sb_opts *opts) { struct cgroupfs_root *root; if (!opts->subsys_bits && !opts->none) return NULL; root = kzalloc(sizeof(*root), GFP_KERNEL); if (!root) return ERR_PTR(-ENOMEM); if (!init_root_id(root)) { kfree(root); return ERR_PTR(-ENOMEM); } init_cgroup_root(root); root->subsys_bits = opts->subsys_bits; root->flags = opts->flags; if (opts->release_agent) strcpy(root->release_agent_path, opts->release_agent); if (opts->name) strcpy(root->name, opts->name); if (opts->clone_children) set_bit(CGRP_CLONE_CHILDREN, &root->top_cgroup.flags); return root; } static void cgroup_drop_root(struct cgroupfs_root *root) { if (!root) return; BUG_ON(!root->hierarchy_id); spin_lock(&hierarchy_id_lock); ida_remove(&hierarchy_ida, root->hierarchy_id); spin_unlock(&hierarchy_id_lock); kfree(root); } static int cgroup_set_super(struct super_block *sb, void *data) { int ret; struct cgroup_sb_opts *opts = data; if (!opts->new_root) return -EINVAL; BUG_ON(!opts->subsys_bits && !opts->none); ret = set_anon_super(sb, NULL); if (ret) return ret; sb->s_fs_info = opts->new_root; opts->new_root->sb = sb; sb->s_blocksize = PAGE_CACHE_SIZE; sb->s_blocksize_bits = PAGE_CACHE_SHIFT; sb->s_magic = CGROUP_SUPER_MAGIC; sb->s_op = &cgroup_ops; return 0; } static int cgroup_get_rootdir(struct super_block *sb) { static const struct dentry_operations cgroup_dops = { .d_iput = cgroup_diput, .d_delete = cgroup_delete, }; struct inode *inode = cgroup_new_inode(S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR, sb); if (!inode) return -ENOMEM; inode->i_fop = &simple_dir_operations; inode->i_op = &cgroup_dir_inode_operations; inc_nlink(inode); sb->s_root = d_make_root(inode); if (!sb->s_root) return -ENOMEM; sb->s_d_op = &cgroup_dops; return 0; } static struct dentry *cgroup_mount(struct file_system_type *fs_type, int flags, const char *unused_dev_name, void *data) { struct cgroup_sb_opts opts; struct cgroupfs_root *root; int ret = 0; struct super_block *sb; struct cgroupfs_root *new_root; struct inode *inode; mutex_lock(&cgroup_mutex); ret = parse_cgroupfs_options(data, &opts); mutex_unlock(&cgroup_mutex); if (ret) goto out_err; new_root = cgroup_root_from_opts(&opts); if (IS_ERR(new_root)) { ret = PTR_ERR(new_root); goto drop_modules; } opts.new_root = new_root; sb = sget(fs_type, cgroup_test_super, cgroup_set_super, &opts); if (IS_ERR(sb)) { ret = PTR_ERR(sb); cgroup_drop_root(opts.new_root); goto drop_modules; } root = sb->s_fs_info; BUG_ON(!root); if (root == opts.new_root) { struct list_head tmp_cg_links; struct cgroup *root_cgrp = &root->top_cgroup; struct cgroupfs_root *existing_root; const struct cred *cred; int i; BUG_ON(sb->s_root != NULL); ret = cgroup_get_rootdir(sb); if (ret) goto drop_new_super; inode = sb->s_root->d_inode; mutex_lock(&inode->i_mutex); mutex_lock(&cgroup_mutex); mutex_lock(&cgroup_root_mutex); ret = -EBUSY; if (strlen(root->name)) for_each_active_root(existing_root) if (!strcmp(existing_root->name, root->name)) goto unlock_drop; ret = allocate_cg_links(css_set_count, &tmp_cg_links); if (ret) goto unlock_drop; ret = rebind_subsystems(root, root->subsys_bits); if (ret == -EBUSY) { free_cg_links(&tmp_cg_links); goto unlock_drop; } BUG_ON(ret); list_add(&root->root_list, &roots); root_count++; sb->s_root->d_fsdata = root_cgrp; root->top_cgroup.dentry = sb->s_root; write_lock(&css_set_lock); for (i = 0; i < CSS_SET_TABLE_SIZE; i++) { struct hlist_head *hhead = &css_set_table[i]; struct hlist_node *node; struct css_set *cg; hlist_for_each_entry(cg, node, hhead, hlist) link_css_set(&tmp_cg_links, cg, root_cgrp); } write_unlock(&css_set_lock); free_cg_links(&tmp_cg_links); BUG_ON(!list_empty(&root_cgrp->sibling)); BUG_ON(!list_empty(&root_cgrp->children)); BUG_ON(root->number_of_cgroups != 1); cred = override_creds(&init_cred); cgroup_populate_dir(root_cgrp); revert_creds(cred); mutex_unlock(&cgroup_root_mutex); mutex_unlock(&cgroup_mutex); mutex_unlock(&inode->i_mutex); } else { cgroup_drop_root(opts.new_root); drop_parsed_module_refcounts(opts.subsys_bits); } kfree(opts.release_agent); kfree(opts.name); return dget(sb->s_root); unlock_drop: mutex_unlock(&cgroup_root_mutex); mutex_unlock(&cgroup_mutex); mutex_unlock(&inode->i_mutex); drop_new_super: deactivate_locked_super(sb); drop_modules: drop_parsed_module_refcounts(opts.subsys_bits); out_err: kfree(opts.release_agent); kfree(opts.name); return ERR_PTR(ret); } static void cgroup_kill_sb(struct super_block *sb) { struct cgroupfs_root *root = sb->s_fs_info; struct cgroup *cgrp = &root->top_cgroup; int ret; struct cg_cgroup_link *link; struct cg_cgroup_link *saved_link; BUG_ON(!root); BUG_ON(root->number_of_cgroups != 1); BUG_ON(!list_empty(&cgrp->children)); BUG_ON(!list_empty(&cgrp->sibling)); mutex_lock(&cgroup_mutex); mutex_lock(&cgroup_root_mutex); ret = rebind_subsystems(root, 0); BUG_ON(ret); write_lock(&css_set_lock); list_for_each_entry_safe(link, saved_link, &cgrp->css_sets, cgrp_link_list) { list_del(&link->cg_link_list); list_del(&link->cgrp_link_list); kfree(link); } write_unlock(&css_set_lock); if (!list_empty(&root->root_list)) { list_del(&root->root_list); root_count--; } mutex_unlock(&cgroup_root_mutex); mutex_unlock(&cgroup_mutex); kill_litter_super(sb); cgroup_drop_root(root); } static struct file_system_type cgroup_fs_type = { .name = "cgroup", .mount = cgroup_mount, .kill_sb = cgroup_kill_sb, }; static struct kobject *cgroup_kobj; static inline struct cgroup *__d_cgrp(struct dentry *dentry) { return dentry->d_fsdata; } static inline struct cftype *__d_cft(struct dentry *dentry) { return dentry->d_fsdata; } int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen) { char *start; struct dentry *dentry = rcu_dereference_check(cgrp->dentry, cgroup_lock_is_held()); if (!dentry || cgrp == dummytop) { strcpy(buf, "/"); return 0; } start = buf + buflen; *--start = '\0'; for (;;) { int len = dentry->d_name.len; if ((start -= len) < buf) return -ENAMETOOLONG; memcpy(start, dentry->d_name.name, len); cgrp = cgrp->parent; if (!cgrp) break; dentry = rcu_dereference_check(cgrp->dentry, cgroup_lock_is_held()); if (!cgrp->parent) continue; if (--start < buf) return -ENAMETOOLONG; *start = '/'; } memmove(buf, start, buf + buflen - start); return 0; } EXPORT_SYMBOL_GPL(cgroup_path); struct task_and_cgroup { struct task_struct *task; struct cgroup *cgrp; struct css_set *cg; }; struct cgroup_taskset { struct task_and_cgroup single; struct flex_array *tc_array; int tc_array_len; int idx; struct cgroup *cur_cgrp; }; struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset) { if (tset->tc_array) { tset->idx = 0; return cgroup_taskset_next(tset); } else { tset->cur_cgrp = tset->single.cgrp; return tset->single.task; } } EXPORT_SYMBOL_GPL(cgroup_taskset_first); struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset) { struct task_and_cgroup *tc; if (!tset->tc_array || tset->idx >= tset->tc_array_len) return NULL; tc = flex_array_get(tset->tc_array, tset->idx++); tset->cur_cgrp = tc->cgrp; return tc->task; } EXPORT_SYMBOL_GPL(cgroup_taskset_next); struct cgroup *cgroup_taskset_cur_cgroup(struct cgroup_taskset *tset) { return tset->cur_cgrp; } EXPORT_SYMBOL_GPL(cgroup_taskset_cur_cgroup); int cgroup_taskset_size(struct cgroup_taskset *tset) { return tset->tc_array ? tset->tc_array_len : 1; } EXPORT_SYMBOL_GPL(cgroup_taskset_size); static void cgroup_task_migrate(struct cgroup *cgrp, struct cgroup *oldcgrp, struct task_struct *tsk, struct css_set *newcg) { struct css_set *oldcg; WARN_ON_ONCE(tsk->flags & PF_EXITING); oldcg = tsk->cgroups; task_lock(tsk); rcu_assign_pointer(tsk->cgroups, newcg); task_unlock(tsk); write_lock(&css_set_lock); if (!list_empty(&tsk->cg_list)) list_move(&tsk->cg_list, &newcg->tasks); write_unlock(&css_set_lock); put_css_set(oldcg); set_bit(CGRP_RELEASABLE, &oldcgrp->flags); } int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk) { int retval = 0; struct cgroup_subsys *ss, *failed_ss = NULL; struct cgroup *oldcgrp; struct cgroupfs_root *root = cgrp->root; struct cgroup_taskset tset = { }; struct css_set *newcg; struct css_set *cg; if (tsk->flags & PF_EXITING) return -ESRCH; oldcgrp = task_cgroup_from_root(tsk, root); if (cgrp == oldcgrp) return 0; tset.single.task = tsk; tset.single.cgrp = oldcgrp; for_each_subsys(root, ss) { if (ss->can_attach) { retval = ss->can_attach(cgrp, &tset); if (retval) { failed_ss = ss; goto out; } } } newcg = find_css_set(tsk->cgroups, cgrp); if (!newcg) { retval = -ENOMEM; goto out; } task_lock(tsk); cg = tsk->cgroups; get_css_set(cg); task_unlock(tsk); cgroup_task_migrate(cgrp, oldcgrp, tsk, newcg); for_each_subsys(root, ss) { if (ss->attach) ss->attach(cgrp, &tset); } set_bit(CGRP_RELEASABLE, &cgrp->flags); put_css_set(cg); cgroup_wakeup_rmdir_waiter(cgrp); out: if (retval) { for_each_subsys(root, ss) { if (ss == failed_ss) break; if (ss->cancel_attach) ss->cancel_attach(cgrp, &tset); } } return retval; } int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk) { struct cgroupfs_root *root; int retval = 0; cgroup_lock(); for_each_active_root(root) { struct cgroup *from_cg = task_cgroup_from_root(from, root); retval = cgroup_attach_task(from_cg, tsk); if (retval) break; } cgroup_unlock(); return retval; } EXPORT_SYMBOL_GPL(cgroup_attach_task_all); static int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader) { int retval, i, group_size; struct cgroup_subsys *ss, *failed_ss = NULL; struct cgroupfs_root *root = cgrp->root; struct task_struct *tsk; struct task_and_cgroup *tc; struct flex_array *group; struct cgroup_taskset tset = { }; group_size = get_nr_threads(leader); group = flex_array_alloc(sizeof(*tc), group_size, GFP_KERNEL); if (!group) return -ENOMEM; retval = flex_array_prealloc(group, 0, group_size - 1, GFP_KERNEL); if (retval) goto out_free_group_list; tsk = leader; i = 0; rcu_read_lock(); do { struct task_and_cgroup ent; if (tsk->flags & PF_EXITING) continue; BUG_ON(i >= group_size); ent.task = tsk; ent.cgrp = task_cgroup_from_root(tsk, root); if (ent.cgrp == cgrp) continue; retval = flex_array_put(group, i, &ent, GFP_ATOMIC); BUG_ON(retval != 0); i++; } while_each_thread(leader, tsk); rcu_read_unlock(); group_size = i; tset.tc_array = group; tset.tc_array_len = group_size; retval = 0; if (!group_size) goto out_free_group_list; for_each_subsys(root, ss) { if (ss->can_attach) { retval = ss->can_attach(cgrp, &tset); if (retval) { failed_ss = ss; goto out_cancel_attach; } } } for (i = 0; i < group_size; i++) { tc = flex_array_get(group, i); tc->cg = find_css_set(tc->task->cgroups, cgrp); if (!tc->cg) { retval = -ENOMEM; goto out_put_css_set_refs; } } for (i = 0; i < group_size; i++) { tc = flex_array_get(group, i); cgroup_task_migrate(cgrp, tc->cgrp, tc->task, tc->cg); } for_each_subsys(root, ss) { if (ss->attach) ss->attach(cgrp, &tset); } synchronize_rcu(); cgroup_wakeup_rmdir_waiter(cgrp); retval = 0; out_put_css_set_refs: if (retval) { for (i = 0; i < group_size; i++) { tc = flex_array_get(group, i); if (!tc->cg) break; put_css_set(tc->cg); } } out_cancel_attach: if (retval) { for_each_subsys(root, ss) { if (ss == failed_ss) break; if (ss->cancel_attach) ss->cancel_attach(cgrp, &tset); } } out_free_group_list: flex_array_free(group); return retval; } static int cgroup_allow_attach(struct cgroup *cgrp, struct cgroup_taskset *tset) { struct cgroup_subsys *ss; int ret; for_each_subsys(cgrp->root, ss) { if (ss->allow_attach) { ret = ss->allow_attach(cgrp, tset); if (ret) return ret; } else { return -EACCES; } } return 0; } static int attach_task_by_pid(struct cgroup *cgrp, u64 pid, bool threadgroup) { struct task_struct *tsk; const struct cred *cred = current_cred(), *tcred; int ret; if (!cgroup_lock_live_group(cgrp)) return -ENODEV; retry_find_task: rcu_read_lock(); if (pid) { tsk = find_task_by_vpid(pid); if (!tsk) { rcu_read_unlock(); ret= -ESRCH; goto out_unlock_cgroup; } tcred = __task_cred(tsk); if (cred->euid && cred->euid != tcred->uid && cred->euid != tcred->suid) { struct cgroup_taskset tset = { }; tset.single.task = tsk; tset.single.cgrp = cgrp; ret = cgroup_allow_attach(cgrp, &tset); if (ret) { rcu_read_unlock(); goto out_unlock_cgroup; } } } else tsk = current; if (threadgroup) tsk = tsk->group_leader; get_task_struct(tsk); rcu_read_unlock(); threadgroup_lock(tsk); if (threadgroup) { if (!thread_group_leader(tsk)) { threadgroup_unlock(tsk); put_task_struct(tsk); goto retry_find_task; } ret = cgroup_attach_proc(cgrp, tsk); } else ret = cgroup_attach_task(cgrp, tsk); threadgroup_unlock(tsk); put_task_struct(tsk); out_unlock_cgroup: cgroup_unlock(); return ret; } static int cgroup_tasks_write(struct cgroup *cgrp, struct cftype *cft, u64 pid) { return attach_task_by_pid(cgrp, pid, false); } static int cgroup_procs_write(struct cgroup *cgrp, struct cftype *cft, u64 tgid) { return attach_task_by_pid(cgrp, tgid, true); } bool cgroup_lock_live_group(struct cgroup *cgrp) { mutex_lock(&cgroup_mutex); if (cgroup_is_removed(cgrp)) { mutex_unlock(&cgroup_mutex); return false; } return true; } EXPORT_SYMBOL_GPL(cgroup_lock_live_group); static int cgroup_release_agent_write(struct cgroup *cgrp, struct cftype *cft, const char *buffer) { BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX); if (strlen(buffer) >= PATH_MAX) return -EINVAL; if (!cgroup_lock_live_group(cgrp)) return -ENODEV; mutex_lock(&cgroup_root_mutex); strcpy(cgrp->root->release_agent_path, buffer); mutex_unlock(&cgroup_root_mutex); cgroup_unlock(); return 0; } static int cgroup_release_agent_show(struct cgroup *cgrp, struct cftype *cft, struct seq_file *seq) { if (!cgroup_lock_live_group(cgrp)) return -ENODEV; seq_puts(seq, cgrp->root->release_agent_path); seq_putc(seq, '\n'); cgroup_unlock(); return 0; } #define CGROUP_LOCAL_BUFFER_SIZE 64 static ssize_t cgroup_write_X64(struct cgroup *cgrp, struct cftype *cft, struct file *file, const char __user *userbuf, size_t nbytes, loff_t *unused_ppos) { char buffer[CGROUP_LOCAL_BUFFER_SIZE]; int retval = 0; char *end; if (!nbytes) return -EINVAL; if (nbytes >= sizeof(buffer)) return -E2BIG; if (copy_from_user(buffer, userbuf, nbytes)) return -EFAULT; buffer[nbytes] = 0; if (cft->write_u64) { u64 val = simple_strtoull(strstrip(buffer), &end, 0); if (*end) return -EINVAL; retval = cft->write_u64(cgrp, cft, val); } else { s64 val = simple_strtoll(strstrip(buffer), &end, 0); if (*end) return -EINVAL; retval = cft->write_s64(cgrp, cft, val); } if (!retval) retval = nbytes; return retval; } static ssize_t cgroup_write_string(struct cgroup *cgrp, struct cftype *cft, struct file *file, const char __user *userbuf, size_t nbytes, loff_t *unused_ppos) { char local_buffer[CGROUP_LOCAL_BUFFER_SIZE]; int retval = 0; size_t max_bytes = cft->max_write_len; char *buffer = local_buffer; if (!max_bytes) max_bytes = sizeof(local_buffer) - 1; if (nbytes >= max_bytes) return -E2BIG; if (nbytes >= sizeof(local_buffer)) { buffer = kmalloc(nbytes + 1, GFP_KERNEL); if (buffer == NULL) return -ENOMEM; } if (nbytes && copy_from_user(buffer, userbuf, nbytes)) { retval = -EFAULT; goto out; } buffer[nbytes] = 0; retval = cft->write_string(cgrp, cft, strstrip(buffer)); if (!retval) retval = nbytes; out: if (buffer != local_buffer) kfree(buffer); return retval; } static ssize_t cgroup_file_write(struct file *file, const char __user *buf, size_t nbytes, loff_t *ppos) { struct cftype *cft = __d_cft(file->f_dentry); struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent); if (cgroup_is_removed(cgrp)) return -ENODEV; if (cft->write) return cft->write(cgrp, cft, file, buf, nbytes, ppos); if (cft->write_u64 || cft->write_s64) return cgroup_write_X64(cgrp, cft, file, buf, nbytes, ppos); if (cft->write_string) return cgroup_write_string(cgrp, cft, file, buf, nbytes, ppos); if (cft->trigger) { int ret = cft->trigger(cgrp, (unsigned int)cft->private); return ret ? ret : nbytes; } return -EINVAL; } static ssize_t cgroup_read_u64(struct cgroup *cgrp, struct cftype *cft, struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) { char tmp[CGROUP_LOCAL_BUFFER_SIZE]; u64 val = cft->read_u64(cgrp, cft); int len = sprintf(tmp, "%llu\n", (unsigned long long) val); return simple_read_from_buffer(buf, nbytes, ppos, tmp, len); } static ssize_t cgroup_read_s64(struct cgroup *cgrp, struct cftype *cft, struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) { char tmp[CGROUP_LOCAL_BUFFER_SIZE]; s64 val = cft->read_s64(cgrp, cft); int len = sprintf(tmp, "%lld\n", (long long) val); return simple_read_from_buffer(buf, nbytes, ppos, tmp, len); } static ssize_t cgroup_file_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) { struct cftype *cft = __d_cft(file->f_dentry); struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent); if (cgroup_is_removed(cgrp)) return -ENODEV; if (cft->read) return cft->read(cgrp, cft, file, buf, nbytes, ppos); if (cft->read_u64) return cgroup_read_u64(cgrp, cft, file, buf, nbytes, ppos); if (cft->read_s64) return cgroup_read_s64(cgrp, cft, file, buf, nbytes, ppos); return -EINVAL; } struct cgroup_seqfile_state { struct cftype *cft; struct cgroup *cgroup; }; static int cgroup_map_add(struct cgroup_map_cb *cb, const char *key, u64 value) { struct seq_file *sf = cb->state; return seq_printf(sf, "%s %llu\n", key, (unsigned long long)value); } static int cgroup_seqfile_show(struct seq_file *m, void *arg) { struct cgroup_seqfile_state *state = m->private; struct cftype *cft = state->cft; if (cft->read_map) { struct cgroup_map_cb cb = { .fill = cgroup_map_add, .state = m, }; return cft->read_map(state->cgroup, cft, &cb); } return cft->read_seq_string(state->cgroup, cft, m); } static int cgroup_seqfile_release(struct inode *inode, struct file *file) { struct seq_file *seq = file->private_data; kfree(seq->private); return single_release(inode, file); } static const struct file_operations cgroup_seqfile_operations = { .read = seq_read, .write = cgroup_file_write, .llseek = seq_lseek, .release = cgroup_seqfile_release, }; static int cgroup_file_open(struct inode *inode, struct file *file) { int err; struct cftype *cft; err = generic_file_open(inode, file); if (err) return err; cft = __d_cft(file->f_dentry); if (cft->read_map || cft->read_seq_string) { struct cgroup_seqfile_state *state = kzalloc(sizeof(*state), GFP_USER); if (!state) return -ENOMEM; state->cft = cft; state->cgroup = __d_cgrp(file->f_dentry->d_parent); file->f_op = &cgroup_seqfile_operations; err = single_open(file, cgroup_seqfile_show, state); if (err < 0) kfree(state); } else if (cft->open) err = cft->open(inode, file); else err = 0; return err; } static int cgroup_file_release(struct inode *inode, struct file *file) { struct cftype *cft = __d_cft(file->f_dentry); if (cft->release) return cft->release(inode, file); return 0; } static int cgroup_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) { if (!S_ISDIR(old_dentry->d_inode->i_mode)) return -ENOTDIR; if (new_dentry->d_inode) return -EEXIST; if (old_dir != new_dir) return -EIO; return simple_rename(old_dir, old_dentry, new_dir, new_dentry); } static const struct file_operations cgroup_file_operations = { .read = cgroup_file_read, .write = cgroup_file_write, .llseek = generic_file_llseek, .open = cgroup_file_open, .release = cgroup_file_release, }; static const struct inode_operations cgroup_dir_inode_operations = { .lookup = cgroup_lookup, .mkdir = cgroup_mkdir, .rmdir = cgroup_rmdir, .rename = cgroup_rename, }; static struct dentry *cgroup_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) { if (dentry->d_name.len > NAME_MAX) return ERR_PTR(-ENAMETOOLONG); d_add(dentry, NULL); return NULL; } static inline struct cftype *__file_cft(struct file *file) { if (file->f_dentry->d_inode->i_fop != &cgroup_file_operations) return ERR_PTR(-EINVAL); return __d_cft(file->f_dentry); } static int cgroup_create_file(struct dentry *dentry, umode_t mode, struct super_block *sb) { struct inode *inode; if (!dentry) return -ENOENT; if (dentry->d_inode) return -EEXIST; inode = cgroup_new_inode(mode, sb); if (!inode) return -ENOMEM; if (S_ISDIR(mode)) { inode->i_op = &cgroup_dir_inode_operations; inode->i_fop = &simple_dir_operations; inc_nlink(inode); mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD); } else if (S_ISREG(mode)) { inode->i_size = 0; inode->i_fop = &cgroup_file_operations; } d_instantiate(dentry, inode); dget(dentry); return 0; } static int cgroup_create_dir(struct cgroup *cgrp, struct dentry *dentry, umode_t mode) { struct dentry *parent; int error = 0; parent = cgrp->parent->dentry; error = cgroup_create_file(dentry, S_IFDIR | mode, cgrp->root->sb); if (!error) { dentry->d_fsdata = cgrp; inc_nlink(parent->d_inode); rcu_assign_pointer(cgrp->dentry, dentry); dget(dentry); } dput(dentry); return error; } static umode_t cgroup_file_mode(const struct cftype *cft) { umode_t mode = 0; if (cft->mode) return cft->mode; if (cft->read || cft->read_u64 || cft->read_s64 || cft->read_map || cft->read_seq_string) mode |= S_IRUGO; if (cft->write || cft->write_u64 || cft->write_s64 || cft->write_string || cft->trigger) mode |= S_IWUSR; return mode; } int cgroup_add_file(struct cgroup *cgrp, struct cgroup_subsys *subsys, const struct cftype *cft) { struct dentry *dir = cgrp->dentry; struct dentry *dentry; int error; umode_t mode; char name[MAX_CGROUP_TYPE_NAMELEN + MAX_CFTYPE_NAME + 2] = { 0 }; if (subsys && !test_bit(ROOT_NOPREFIX, &cgrp->root->flags)) { strcpy(name, subsys->name); strcat(name, "."); } strcat(name, cft->name); BUG_ON(!mutex_is_locked(&dir->d_inode->i_mutex)); dentry = lookup_one_len(name, dir, strlen(name)); if (!IS_ERR(dentry)) { mode = cgroup_file_mode(cft); error = cgroup_create_file(dentry, mode | S_IFREG, cgrp->root->sb); if (!error) dentry->d_fsdata = (void *)cft; dput(dentry); } else error = PTR_ERR(dentry); return error; } EXPORT_SYMBOL_GPL(cgroup_add_file); int cgroup_add_files(struct cgroup *cgrp, struct cgroup_subsys *subsys, const struct cftype cft[], int count) { int i, err; for (i = 0; i < count; i++) { err = cgroup_add_file(cgrp, subsys, &cft[i]); if (err) return err; } return 0; } EXPORT_SYMBOL_GPL(cgroup_add_files); int cgroup_task_count(const struct cgroup *cgrp) { int count = 0; struct cg_cgroup_link *link; read_lock(&css_set_lock); list_for_each_entry(link, &cgrp->css_sets, cgrp_link_list) { count += atomic_read(&link->cg->refcount); } read_unlock(&css_set_lock); return count; } static void cgroup_advance_iter(struct cgroup *cgrp, struct cgroup_iter *it) { struct list_head *l = it->cg_link; struct cg_cgroup_link *link; struct css_set *cg; do { l = l->next; if (l == &cgrp->css_sets) { it->cg_link = NULL; return; } link = list_entry(l, struct cg_cgroup_link, cgrp_link_list); cg = link->cg; } while (list_empty(&cg->tasks)); it->cg_link = l; it->task = cg->tasks.next; } static void cgroup_enable_task_cg_lists(void) { struct task_struct *p, *g; write_lock(&css_set_lock); use_task_css_set_links = 1; read_lock(&tasklist_lock); do_each_thread(g, p) { task_lock(p); if (!(p->flags & PF_EXITING) && list_empty(&p->cg_list)) list_add(&p->cg_list, &p->cgroups->tasks); task_unlock(p); } while_each_thread(g, p); read_unlock(&tasklist_lock); write_unlock(&css_set_lock); } void cgroup_iter_start(struct cgroup *cgrp, struct cgroup_iter *it) __acquires(css_set_lock) { if (!use_task_css_set_links) cgroup_enable_task_cg_lists(); read_lock(&css_set_lock); it->cg_link = &cgrp->css_sets; cgroup_advance_iter(cgrp, it); } struct task_struct *cgroup_iter_next(struct cgroup *cgrp, struct cgroup_iter *it) { struct task_struct *res; struct list_head *l = it->task; struct cg_cgroup_link *link; if (!it->cg_link) return NULL; res = list_entry(l, struct task_struct, cg_list); l = l->next; link = list_entry(it->cg_link, struct cg_cgroup_link, cgrp_link_list); if (l == &link->cg->tasks) { cgroup_advance_iter(cgrp, it); } else { it->task = l; } return res; } void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it) __releases(css_set_lock) { read_unlock(&css_set_lock); } static inline int started_after_time(struct task_struct *t1, struct timespec *time, struct task_struct *t2) { int start_diff = timespec_compare(&t1->start_time, time); if (start_diff > 0) { return 1; } else if (start_diff < 0) { return 0; } else { return t1 > t2; } } static inline int started_after(void *p1, void *p2) { struct task_struct *t1 = p1; struct task_struct *t2 = p2; return started_after_time(t1, &t2->start_time, t2); } /** * cgroup_scan_tasks - iterate though all the tasks in a cgroup * @scan: struct cgroup_scanner containing arguments for the scan * * Arguments include pointers to callback functions test_task() and * process_task(). * Iterate through all the tasks in a cgroup, calling test_task() for each, * and if it returns true, call process_task() for it also. * The test_task pointer may be NULL, meaning always true (select all tasks). * Effectively duplicates cgroup_iter_{start,next,end}() * but does not lock css_set_lock for the call to process_task(). * The struct cgroup_scanner may be embedded in any structure of the caller's * creation. * It is guaranteed that process_task() will act on every task that * is a member of the cgroup for the duration of this call. This * function may or may not call process_task() for tasks that exit * or move to a different cgroup during the call, or are forked or * move into the cgroup during the call. * * Note that test_task() may be called with locks held, and may in some * situations be called multiple times for the same task, so it should * be cheap. * If the heap pointer in the struct cgroup_scanner is non-NULL, a heap has been * pre-allocated and will be used for heap operations (and its "gt" member will * be overwritten), else a temporary heap will be used (allocation of which * may cause this function to fail). */ int cgroup_scan_tasks(struct cgroup_scanner *scan) { int retval, i; struct cgroup_iter it; struct task_struct *p, *dropped; struct task_struct *latest_task = NULL; struct ptr_heap tmp_heap; struct ptr_heap *heap; struct timespec latest_time = { 0, 0 }; if (scan->heap) { heap = scan->heap; heap->gt = &started_after; } else { heap = &tmp_heap; retval = heap_init(heap, PAGE_SIZE, GFP_KERNEL, &started_after); if (retval) return retval; } again: heap->size = 0; cgroup_iter_start(scan->cg, &it); while ((p = cgroup_iter_next(scan->cg, &it))) { if (scan->test_task && !scan->test_task(p, scan)) continue; if (!started_after_time(p, &latest_time, latest_task)) continue; dropped = heap_insert(heap, p); if (dropped == NULL) { get_task_struct(p); } else if (dropped != p) { get_task_struct(p); put_task_struct(dropped); } } cgroup_iter_end(scan->cg, &it); if (heap->size) { for (i = 0; i < heap->size; i++) { struct task_struct *q = heap->ptrs[i]; if (i == 0) { latest_time = q->start_time; latest_task = q; } scan->process_task(q, scan); put_task_struct(q); } goto again; } if (heap == &tmp_heap) heap_free(&tmp_heap); return 0; } enum cgroup_filetype { CGROUP_FILE_PROCS, CGROUP_FILE_TASKS, }; struct cgroup_pidlist { struct { enum cgroup_filetype type; struct pid_namespace *ns; } key; pid_t *list; int length; int use_count; struct list_head links; struct cgroup *owner; struct rw_semaphore mutex; }; #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) { if (is_vmalloc_addr(p)) vfree(p); else kfree(p); } static void *pidlist_resize(void *p, int newcount) { void *newlist; if (is_vmalloc_addr(p)) { newlist = vmalloc(newcount * sizeof(pid_t)); if (!newlist) return NULL; memcpy(newlist, p, newcount * sizeof(pid_t)); vfree(p); } else { newlist = krealloc(p, newcount * sizeof(pid_t), GFP_KERNEL); } return newlist; } #define PIDLIST_REALLOC_DIFFERENCE(old, new) ((old) - PAGE_SIZE >= (new)) static int pidlist_uniq(pid_t **p, int length) { int src, dest = 1; pid_t *list = *p; pid_t *newlist; if (length == 0 || length == 1) return length; for (src = 1; src < length; src++) { while (list[src] == list[src-1]) { src++; if (src == length) goto after; } list[dest] = list[src]; dest++; } after: if (PIDLIST_REALLOC_DIFFERENCE(length, dest)) { newlist = pidlist_resize(list, dest); if (newlist) *p = newlist; } return dest; } 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; struct pid_namespace *ns = current->nsproxy->pid_ns; mutex_lock(&cgrp->pidlist_mutex); list_for_each_entry(l, &cgrp->pidlists, links) { if (l->key.type == type && l->key.ns == ns) { down_write(&l->mutex); mutex_unlock(&cgrp->pidlist_mutex); return l; } } l = kmalloc(sizeof(struct cgroup_pidlist), GFP_KERNEL); if (!l) { mutex_unlock(&cgrp->pidlist_mutex); return l; } init_rwsem(&l->mutex); down_write(&l->mutex); l->key.type = type; l->key.ns = get_pid_ns(ns); l->use_count = 0; l->list = NULL; l->owner = cgrp; list_add(&l->links, &cgrp->pidlists); mutex_unlock(&cgrp->pidlist_mutex); return l; } 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; struct cgroup_iter it; struct task_struct *tsk; struct cgroup_pidlist *l; length = cgroup_task_count(cgrp); array = pidlist_allocate(length); if (!array) return -ENOMEM; cgroup_iter_start(cgrp, &it); while ((tsk = cgroup_iter_next(cgrp, &it))) { if (unlikely(n == length)) break; if (type == CGROUP_FILE_PROCS) pid = task_tgid_vnr(tsk); else pid = task_pid_vnr(tsk); if (pid > 0) array[n++] = pid; } cgroup_iter_end(cgrp, &it); length = n; sort(array, length, sizeof(pid_t), cmppid, NULL); if (type == CGROUP_FILE_PROCS) length = pidlist_uniq(&array, length); l = cgroup_pidlist_find(cgrp, type); if (!l) { pidlist_free(array); return -ENOMEM; } pidlist_free(l->list); l->list = array; l->length = length; l->use_count++; up_write(&l->mutex); *lp = l; return 0; } int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry) { int ret = -EINVAL; struct cgroup *cgrp; struct cgroup_iter it; struct task_struct *tsk; if (dentry->d_sb->s_op != &cgroup_ops || !S_ISDIR(dentry->d_inode->i_mode)) goto err; ret = 0; cgrp = dentry->d_fsdata; cgroup_iter_start(cgrp, &it); while ((tsk = cgroup_iter_next(cgrp, &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; } } cgroup_iter_end(cgrp, &it); err: return ret; } static void *cgroup_pidlist_start(struct seq_file *s, loff_t *pos) { struct cgroup_pidlist *l = s->private; int index = 0, pid = *pos; int *iter; down_read(&l->mutex); 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 (index >= l->length) return NULL; iter = l->list + index; *pos = *iter; return iter; } static void cgroup_pidlist_stop(struct seq_file *s, void *v) { struct cgroup_pidlist *l = s->private; up_read(&l->mutex); } static void *cgroup_pidlist_next(struct seq_file *s, void *v, loff_t *pos) { struct cgroup_pidlist *l = s->private; pid_t *p = v; pid_t *end = l->list + l->length; p++; if (p >= end) { return NULL; } else { *pos = *p; return p; } } static int cgroup_pidlist_show(struct seq_file *s, void *v) { return seq_printf(s, "%d\n", *(int *)v); } static const struct seq_operations cgroup_pidlist_seq_operations = { .start = cgroup_pidlist_start, .stop = cgroup_pidlist_stop, .next = cgroup_pidlist_next, .show = cgroup_pidlist_show, }; static void cgroup_release_pid_array(struct cgroup_pidlist *l) { mutex_lock(&l->owner->pidlist_mutex); down_write(&l->mutex); BUG_ON(!l->use_count); if (!--l->use_count) { list_del(&l->links); mutex_unlock(&l->owner->pidlist_mutex); pidlist_free(l->list); put_pid_ns(l->key.ns); up_write(&l->mutex); kfree(l); return; } mutex_unlock(&l->owner->pidlist_mutex); up_write(&l->mutex); } static int cgroup_pidlist_release(struct inode *inode, struct file *file) { struct cgroup_pidlist *l; if (!(file->f_mode & FMODE_READ)) return 0; l = ((struct seq_file *)file->private_data)->private; cgroup_release_pid_array(l); return seq_release(inode, file); } static const struct file_operations cgroup_pidlist_operations = { .read = seq_read, .llseek = seq_lseek, .write = cgroup_file_write, .release = cgroup_pidlist_release, }; static int cgroup_pidlist_open(struct file *file, enum cgroup_filetype type) { struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent); struct cgroup_pidlist *l; int retval; if (!(file->f_mode & FMODE_READ)) return 0; retval = pidlist_array_load(cgrp, type, &l); if (retval) return retval; file->f_op = &cgroup_pidlist_operations; retval = seq_open(file, &cgroup_pidlist_seq_operations); if (retval) { cgroup_release_pid_array(l); return retval; } ((struct seq_file *)file->private_data)->private = l; return 0; } static int cgroup_tasks_open(struct inode *unused, struct file *file) { return cgroup_pidlist_open(file, CGROUP_FILE_TASKS); } static int cgroup_procs_open(struct inode *unused, struct file *file) { return cgroup_pidlist_open(file, CGROUP_FILE_PROCS); } static u64 cgroup_read_notify_on_release(struct cgroup *cgrp, struct cftype *cft) { return notify_on_release(cgrp); } static int cgroup_write_notify_on_release(struct cgroup *cgrp, struct cftype *cft, u64 val) { clear_bit(CGRP_RELEASABLE, &cgrp->flags); if (val) set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); else clear_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); return 0; } static void cgroup_event_remove(struct work_struct *work) { struct cgroup_event *event = container_of(work, struct cgroup_event, remove); struct cgroup *cgrp = event->cgrp; event->cft->unregister_event(cgrp, event->cft, event->eventfd); eventfd_ctx_put(event->eventfd); kfree(event); dput(cgrp->dentry); } static int cgroup_event_wake(wait_queue_t *wait, unsigned mode, int sync, void *key) { struct cgroup_event *event = container_of(wait, struct cgroup_event, wait); struct cgroup *cgrp = event->cgrp; unsigned long flags = (unsigned long)key; if (flags & POLLHUP) { __remove_wait_queue(event->wqh, &event->wait); spin_lock(&cgrp->event_list_lock); list_del(&event->list); spin_unlock(&cgrp->event_list_lock); schedule_work(&event->remove); } return 0; } static void cgroup_event_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh, poll_table *pt) { struct cgroup_event *event = container_of(pt, struct cgroup_event, pt); event->wqh = wqh; add_wait_queue(wqh, &event->wait); } static int cgroup_write_event_control(struct cgroup *cgrp, struct cftype *cft, const char *buffer) { struct cgroup_event *event = NULL; unsigned int efd, cfd; struct file *efile = NULL; struct file *cfile = NULL; char *endp; int ret; efd = simple_strtoul(buffer, &endp, 10); if (*endp != ' ') return -EINVAL; buffer = endp + 1; cfd = simple_strtoul(buffer, &endp, 10); if ((*endp != ' ') && (*endp != '\0')) return -EINVAL; buffer = endp + 1; event = kzalloc(sizeof(*event), GFP_KERNEL); if (!event) return -ENOMEM; event->cgrp = cgrp; INIT_LIST_HEAD(&event->list); init_poll_funcptr(&event->pt, cgroup_event_ptable_queue_proc); init_waitqueue_func_entry(&event->wait, cgroup_event_wake); INIT_WORK(&event->remove, cgroup_event_remove); efile = eventfd_fget(efd); if (IS_ERR(efile)) { ret = PTR_ERR(efile); goto fail; } event->eventfd = eventfd_ctx_fileget(efile); if (IS_ERR(event->eventfd)) { ret = PTR_ERR(event->eventfd); goto fail; } cfile = fget(cfd); if (!cfile) { ret = -EBADF; goto fail; } ret = inode_permission(cfile->f_path.dentry->d_inode, MAY_READ); if (ret < 0) goto fail; event->cft = __file_cft(cfile); if (IS_ERR(event->cft)) { ret = PTR_ERR(event->cft); goto fail; } if (!event->cft->register_event || !event->cft->unregister_event) { ret = -EINVAL; goto fail; } ret = event->cft->register_event(cgrp, event->cft, event->eventfd, buffer); if (ret) goto fail; if (efile->f_op->poll(efile, &event->pt) & POLLHUP) { event->cft->unregister_event(cgrp, event->cft, event->eventfd); ret = 0; goto fail; } dget(cgrp->dentry); spin_lock(&cgrp->event_list_lock); list_add(&event->list, &cgrp->event_list); spin_unlock(&cgrp->event_list_lock); fput(cfile); fput(efile); return 0; fail: if (cfile) fput(cfile); if (event && event->eventfd && !IS_ERR(event->eventfd)) eventfd_ctx_put(event->eventfd); if (!IS_ERR_OR_NULL(efile)) fput(efile); kfree(event); return ret; } static u64 cgroup_clone_children_read(struct cgroup *cgrp, struct cftype *cft) { return clone_children(cgrp); } static int cgroup_clone_children_write(struct cgroup *cgrp, struct cftype *cft, u64 val) { if (val) set_bit(CGRP_CLONE_CHILDREN, &cgrp->flags); else clear_bit(CGRP_CLONE_CHILDREN, &cgrp->flags); return 0; } #define CGROUP_FILE_GENERIC_PREFIX "cgroup." static struct cftype files[] = { { .name = "tasks", .open = cgroup_tasks_open, .write_u64 = cgroup_tasks_write, .release = cgroup_pidlist_release, .mode = S_IRUGO | S_IWUSR, }, { .name = CGROUP_FILE_GENERIC_PREFIX "procs", .open = cgroup_procs_open, .write_u64 = cgroup_procs_write, .release = cgroup_pidlist_release, .mode = S_IRUGO | S_IWUSR, }, { .name = "notify_on_release", .read_u64 = cgroup_read_notify_on_release, .write_u64 = cgroup_write_notify_on_release, }, { .name = CGROUP_FILE_GENERIC_PREFIX "event_control", .write_string = cgroup_write_event_control, .mode = S_IWUGO, }, { .name = "cgroup.clone_children", .read_u64 = cgroup_clone_children_read, .write_u64 = cgroup_clone_children_write, }, }; static struct cftype cft_release_agent = { .name = "release_agent", .read_seq_string = cgroup_release_agent_show, .write_string = cgroup_release_agent_write, .max_write_len = PATH_MAX, }; static int cgroup_populate_dir(struct cgroup *cgrp) { int err; struct cgroup_subsys *ss; cgroup_clear_directory(cgrp->dentry); err = cgroup_add_files(cgrp, NULL, files, ARRAY_SIZE(files)); if (err < 0) return err; if (cgrp == cgrp->top_cgroup) { if ((err = cgroup_add_file(cgrp, NULL, &cft_release_agent)) < 0) return err; } for_each_subsys(cgrp->root, ss) { if (ss->populate && (err = ss->populate(ss, cgrp)) < 0) return err; } for_each_subsys(cgrp->root, ss) { struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id]; if (css->id) rcu_assign_pointer(css->id->css, css); } return 0; } static void init_cgroup_css(struct cgroup_subsys_state *css, struct cgroup_subsys *ss, struct cgroup *cgrp) { css->cgroup = cgrp; atomic_set(&css->refcnt, 1); css->flags = 0; css->id = NULL; if (cgrp == dummytop) set_bit(CSS_ROOT, &css->flags); BUG_ON(cgrp->subsys[ss->subsys_id]); cgrp->subsys[ss->subsys_id] = css; } static void cgroup_lock_hierarchy(struct cgroupfs_root *root) { int i; for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; if (ss == NULL) continue; if (ss->root == root) mutex_lock(&ss->hierarchy_mutex); } } static void cgroup_unlock_hierarchy(struct cgroupfs_root *root) { int i; for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; if (ss == NULL) continue; if (ss->root == root) mutex_unlock(&ss->hierarchy_mutex); } } static long cgroup_create(struct cgroup *parent, struct dentry *dentry, umode_t mode) { struct cgroup *cgrp; struct cgroupfs_root *root = parent->root; int err = 0; struct cgroup_subsys *ss; struct super_block *sb = root->sb; cgrp = kzalloc(sizeof(*cgrp), GFP_KERNEL); if (!cgrp) return -ENOMEM; atomic_inc(&sb->s_active); mutex_lock(&cgroup_mutex); init_cgroup_housekeeping(cgrp); cgrp->parent = parent; cgrp->root = parent->root; cgrp->top_cgroup = parent->top_cgroup; if (notify_on_release(parent)) set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); if (clone_children(parent)) set_bit(CGRP_CLONE_CHILDREN, &cgrp->flags); for_each_subsys(root, ss) { struct cgroup_subsys_state *css = ss->create(cgrp); if (IS_ERR(css)) { err = PTR_ERR(css); goto err_destroy; } init_cgroup_css(css, ss, cgrp); if (ss->use_id) { err = alloc_css_id(ss, parent, cgrp); if (err) goto err_destroy; } if (clone_children(parent) && ss->post_clone) ss->post_clone(cgrp); } cgroup_lock_hierarchy(root); list_add(&cgrp->sibling, &cgrp->parent->children); cgroup_unlock_hierarchy(root); root->number_of_cgroups++; err = cgroup_create_dir(cgrp, dentry, mode); if (err < 0) goto err_remove; set_bit(CGRP_RELEASABLE, &parent->flags); BUG_ON(!mutex_is_locked(&cgrp->dentry->d_inode->i_mutex)); err = cgroup_populate_dir(cgrp); mutex_unlock(&cgroup_mutex); mutex_unlock(&cgrp->dentry->d_inode->i_mutex); return 0; err_remove: cgroup_lock_hierarchy(root); list_del(&cgrp->sibling); cgroup_unlock_hierarchy(root); root->number_of_cgroups--; err_destroy: for_each_subsys(root, ss) { if (cgrp->subsys[ss->subsys_id]) ss->destroy(cgrp); } mutex_unlock(&cgroup_mutex); deactivate_super(sb); kfree(cgrp); return err; } static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) { struct cgroup *c_parent = dentry->d_parent->d_fsdata; return cgroup_create(c_parent, dentry, mode | S_IFDIR); } static int cgroup_has_css_refs(struct cgroup *cgrp) { int i; for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; struct cgroup_subsys_state *css; if (ss == NULL || ss->root != cgrp->root) continue; css = cgrp->subsys[ss->subsys_id]; if (css && (atomic_read(&css->refcnt) > 1)) return 1; } return 0; } static int cgroup_clear_css_refs(struct cgroup *cgrp) { struct cgroup_subsys *ss; unsigned long flags; bool failed = false; local_irq_save(flags); for_each_subsys(cgrp->root, ss) { struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id]; int refcnt; while (1) { refcnt = atomic_read(&css->refcnt); if (refcnt > 1) { failed = true; goto done; } BUG_ON(!refcnt); if (atomic_cmpxchg(&css->refcnt, refcnt, 0) == refcnt) break; cpu_relax(); } } done: for_each_subsys(cgrp->root, ss) { struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id]; if (failed) { if (!atomic_read(&css->refcnt)) atomic_set(&css->refcnt, 1); } else { set_bit(CSS_REMOVED, &css->flags); } } local_irq_restore(flags); return !failed; } static int cgroup_css_sets_empty(struct cgroup *cgrp) { struct cg_cgroup_link *link; list_for_each_entry(link, &cgrp->css_sets, cgrp_link_list) { struct css_set *cg = link->cg; if (atomic_read(&cg->refcount) > 0) return 0; } return 1; } static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry) { struct cgroup *cgrp = dentry->d_fsdata; struct dentry *d; struct cgroup *parent; DEFINE_WAIT(wait); struct cgroup_event *event, *tmp; int ret; again: mutex_lock(&cgroup_mutex); if (!cgroup_css_sets_empty(cgrp)) { mutex_unlock(&cgroup_mutex); return -EBUSY; } if (!list_empty(&cgrp->children)) { mutex_unlock(&cgroup_mutex); return -EBUSY; } mutex_unlock(&cgroup_mutex); set_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags); ret = cgroup_call_pre_destroy(cgrp); if (ret) { clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags); return ret; } mutex_lock(&cgroup_mutex); parent = cgrp->parent; if (!cgroup_css_sets_empty(cgrp) || !list_empty(&cgrp->children)) { clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags); mutex_unlock(&cgroup_mutex); return -EBUSY; } prepare_to_wait(&cgroup_rmdir_waitq, &wait, TASK_INTERRUPTIBLE); if (!cgroup_clear_css_refs(cgrp)) { mutex_unlock(&cgroup_mutex); if (test_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags)) schedule(); finish_wait(&cgroup_rmdir_waitq, &wait); clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags); if (signal_pending(current)) return -EINTR; goto again; } finish_wait(&cgroup_rmdir_waitq, &wait); clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags); raw_spin_lock(&release_list_lock); set_bit(CGRP_REMOVED, &cgrp->flags); if (!list_empty(&cgrp->release_list)) list_del_init(&cgrp->release_list); raw_spin_unlock(&release_list_lock); cgroup_lock_hierarchy(cgrp->root); list_del_init(&cgrp->sibling); cgroup_unlock_hierarchy(cgrp->root); d = dget(cgrp->dentry); cgroup_d_remove_dir(d); dput(d); check_for_release(parent); spin_lock(&cgrp->event_list_lock); list_for_each_entry_safe(event, tmp, &cgrp->event_list, list) { list_del(&event->list); remove_wait_queue(event->wqh, &event->wait); eventfd_signal(event->eventfd, 1); schedule_work(&event->remove); } spin_unlock(&cgrp->event_list_lock); mutex_unlock(&cgroup_mutex); return 0; } static void __init cgroup_init_subsys(struct cgroup_subsys *ss) { struct cgroup_subsys_state *css; printk(KERN_INFO "Initializing cgroup subsys %s\n", ss->name); list_add(&ss->sibling, &rootnode.subsys_list); ss->root = &rootnode; css = ss->create(dummytop); BUG_ON(IS_ERR(css)); init_cgroup_css(css, ss, dummytop); init_css_set.subsys[ss->subsys_id] = dummytop->subsys[ss->subsys_id]; need_forkexit_callback |= ss->fork || ss->exit; BUG_ON(!list_empty(&init_task.tasks)); mutex_init(&ss->hierarchy_mutex); lockdep_set_class(&ss->hierarchy_mutex, &ss->subsys_key); ss->active = 1; BUG_ON(ss->module); } int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) { int i; struct cgroup_subsys_state *css; if (ss->name == NULL || strlen(ss->name) > MAX_CGROUP_TYPE_NAMELEN || ss->create == NULL || ss->destroy == NULL) return -EINVAL; if (ss->fork || ss->exit) return -EINVAL; if (ss->module == NULL) { BUG_ON(ss->subsys_id >= CGROUP_BUILTIN_SUBSYS_COUNT); BUG_ON(subsys[ss->subsys_id] != ss); return 0; } mutex_lock(&cgroup_mutex); for (i = CGROUP_BUILTIN_SUBSYS_COUNT; i < CGROUP_SUBSYS_COUNT; i++) { if (subsys[i] == NULL) break; } if (i == CGROUP_SUBSYS_COUNT) { mutex_unlock(&cgroup_mutex); return -EBUSY; } ss->subsys_id = i; subsys[i] = ss; css = ss->create(dummytop); if (IS_ERR(css)) { subsys[i] = NULL; mutex_unlock(&cgroup_mutex); return PTR_ERR(css); } list_add(&ss->sibling, &rootnode.subsys_list); ss->root = &rootnode; init_cgroup_css(css, ss, dummytop); if (ss->use_id) { int ret = cgroup_init_idr(ss, css); if (ret) { dummytop->subsys[ss->subsys_id] = NULL; ss->destroy(dummytop); subsys[i] = NULL; mutex_unlock(&cgroup_mutex); return ret; } } write_lock(&css_set_lock); for (i = 0; i < CSS_SET_TABLE_SIZE; i++) { struct css_set *cg; struct hlist_node *node, *tmp; struct hlist_head *bucket = &css_set_table[i], *new_bucket; hlist_for_each_entry_safe(cg, node, tmp, bucket, hlist) { if (cg->subsys[ss->subsys_id]) continue; hlist_del(&cg->hlist); cg->subsys[ss->subsys_id] = css; new_bucket = css_set_hash(cg->subsys); hlist_add_head(&cg->hlist, new_bucket); } } write_unlock(&css_set_lock); mutex_init(&ss->hierarchy_mutex); lockdep_set_class(&ss->hierarchy_mutex, &ss->subsys_key); ss->active = 1; mutex_unlock(&cgroup_mutex); return 0; } EXPORT_SYMBOL_GPL(cgroup_load_subsys); void cgroup_unload_subsys(struct cgroup_subsys *ss) { struct cg_cgroup_link *link; struct hlist_head *hhead; BUG_ON(ss->module == NULL); BUG_ON(ss->root != &rootnode); mutex_lock(&cgroup_mutex); BUG_ON(ss->subsys_id < CGROUP_BUILTIN_SUBSYS_COUNT); subsys[ss->subsys_id] = NULL; list_del_init(&ss->sibling); write_lock(&css_set_lock); list_for_each_entry(link, &dummytop->css_sets, cgrp_link_list) { struct css_set *cg = link->cg; hlist_del(&cg->hlist); BUG_ON(!cg->subsys[ss->subsys_id]); cg->subsys[ss->subsys_id] = NULL; hhead = css_set_hash(cg->subsys); hlist_add_head(&cg->hlist, hhead); } write_unlock(&css_set_lock); ss->destroy(dummytop); dummytop->subsys[ss->subsys_id] = NULL; mutex_unlock(&cgroup_mutex); } EXPORT_SYMBOL_GPL(cgroup_unload_subsys); int __init cgroup_init_early(void) { int i; atomic_set(&init_css_set.refcount, 1); INIT_LIST_HEAD(&init_css_set.cg_links); INIT_LIST_HEAD(&init_css_set.tasks); INIT_HLIST_NODE(&init_css_set.hlist); css_set_count = 1; init_cgroup_root(&rootnode); root_count = 1; init_task.cgroups = &init_css_set; init_css_set_link.cg = &init_css_set; init_css_set_link.cgrp = dummytop; list_add(&init_css_set_link.cgrp_link_list, &rootnode.top_cgroup.css_sets); list_add(&init_css_set_link.cg_link_list, &init_css_set.cg_links); for (i = 0; i < CSS_SET_TABLE_SIZE; i++) INIT_HLIST_HEAD(&css_set_table[i]); for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; BUG_ON(!ss->name); BUG_ON(strlen(ss->name) > MAX_CGROUP_TYPE_NAMELEN); BUG_ON(!ss->create); BUG_ON(!ss->destroy); if (ss->subsys_id != i) { printk(KERN_ERR "cgroup: Subsys %s id == %d\n", ss->name, ss->subsys_id); BUG(); } if (ss->early_init) cgroup_init_subsys(ss); } return 0; } int __init cgroup_init(void) { int err; int i; struct hlist_head *hhead; err = bdi_init(&cgroup_backing_dev_info); if (err) return err; for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; if (!ss->early_init) cgroup_init_subsys(ss); if (ss->use_id) cgroup_init_idr(ss, init_css_set.subsys[ss->subsys_id]); } hhead = css_set_hash(init_css_set.subsys); hlist_add_head(&init_css_set.hlist, hhead); BUG_ON(!init_root_id(&rootnode)); cgroup_kobj = kobject_create_and_add("cgroup", fs_kobj); if (!cgroup_kobj) { err = -ENOMEM; goto out; } err = register_filesystem(&cgroup_fs_type); if (err < 0) { kobject_put(cgroup_kobj); goto out; } proc_create("cgroups", 0, NULL, &proc_cgroupstats_operations); out: if (err) bdi_destroy(&cgroup_backing_dev_info); return err; } static int proc_cgroup_show(struct seq_file *m, void *v) { struct pid *pid; struct task_struct *tsk; char *buf; int retval; struct cgroupfs_root *root; retval = -ENOMEM; buf = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!buf) goto out; retval = -ESRCH; pid = m->private; tsk = get_pid_task(pid, PIDTYPE_PID); if (!tsk) goto out_free; retval = 0; mutex_lock(&cgroup_mutex); for_each_active_root(root) { struct cgroup_subsys *ss; struct cgroup *cgrp; int count = 0; seq_printf(m, "%d:", root->hierarchy_id); for_each_subsys(root, ss) seq_printf(m, "%s%s", count++ ? "," : "", ss->name); if (strlen(root->name)) seq_printf(m, "%sname=%s", count ? "," : "", root->name); seq_putc(m, ':'); cgrp = task_cgroup_from_root(tsk, root); retval = cgroup_path(cgrp, buf, PAGE_SIZE); if (retval < 0) goto out_unlock; seq_puts(m, buf); seq_putc(m, '\n'); } out_unlock: mutex_unlock(&cgroup_mutex); put_task_struct(tsk); out_free: kfree(buf); out: return retval; } static int cgroup_open(struct inode *inode, struct file *file) { struct pid *pid = PROC_I(inode)->pid; return single_open(file, proc_cgroup_show, pid); } const struct file_operations proc_cgroup_operations = { .open = cgroup_open, .read = seq_read, .llseek = seq_lseek, .release = single_release, }; static int proc_cgroupstats_show(struct seq_file *m, void *v) { int i; seq_puts(m, "#subsys_name\thierarchy\tnum_cgroups\tenabled\n"); mutex_lock(&cgroup_mutex); for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; if (ss == NULL) continue; seq_printf(m, "%s\t%d\t%d\t%d\n", ss->name, ss->root->hierarchy_id, ss->root->number_of_cgroups, !ss->disabled); } 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, }; void cgroup_fork(struct task_struct *child) { child->cgroups = current->cgroups; get_css_set(child->cgroups); INIT_LIST_HEAD(&child->cg_list); } /** * cgroup_post_fork - called on a new task after adding it to the task list * @child: the task in question * * Adds the task to the list running through its css_set if necessary and * call the subsystem fork() callbacks. Has to be after the task is * visible on the task list in case we race with the first call to * cgroup_iter_start() - to guarantee that the new task ends up on its * list. */ void cgroup_post_fork(struct task_struct *child) { int i; /* * use_task_css_set_links is set to 1 before we walk the tasklist * under the tasklist_lock and we read it here after we added the child * to the tasklist under the tasklist_lock as well. If the child wasn't * yet in the tasklist when we walked through it from * cgroup_enable_task_cg_lists(), then use_task_css_set_links value * should be visible now due to the paired locking and barriers implied * by LOCK/UNLOCK: it is written before the tasklist_lock unlock * in cgroup_enable_task_cg_lists() and read here after the tasklist_lock * lock on fork. */ if (use_task_css_set_links) { write_lock(&css_set_lock); if (list_empty(&child->cg_list)) { list_add(&child->cg_list, &child->cgroups->tasks); } write_unlock(&css_set_lock); } /* * Call ss->fork(). This must happen after @child is linked on * css_set; otherwise, @child might change state between ->fork() * and addition to css_set. */ if (need_forkexit_callback) { for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; if (ss->fork) ss->fork(child); } } } /** * cgroup_exit - detach cgroup from exiting task * @tsk: pointer to task_struct of exiting process * @run_callback: run exit callbacks? * * Description: Detach cgroup from @tsk and release it. * * Note that cgroups marked notify_on_release force every task in * them to take the global cgroup_mutex mutex when exiting. * This could impact scaling on very large systems. Be reluctant to * use notify_on_release cgroups where very high task exit scaling * is required on large systems. * * the_top_cgroup_hack: * * Set the exiting tasks cgroup to the root cgroup (top_cgroup). * * We call cgroup_exit() while the task is still competent to * handle notify_on_release(), then leave the task attached to the * root cgroup in each hierarchy for the remainder of its exit. * * To do this properly, we would increment the reference count on * top_cgroup, and near the very end of the kernel/exit.c do_exit() * code we would add a second cgroup function call, to drop that * reference. This would just create an unnecessary hot spot on * the top_cgroup reference count, to no avail. * * Normally, holding a reference to a cgroup without bumping its * count is unsafe. The cgroup could go away, or someone could * attach us to a different cgroup, decrementing the count on * the first cgroup that we never incremented. But in this case, * top_cgroup isn't going away, and either task has PF_EXITING set, * which wards off any cgroup_attach_task() attempts, or task is a failed * fork, never visible to cgroup_attach_task. */ void cgroup_exit(struct task_struct *tsk, int run_callbacks) { struct css_set *cg; int i; if (!list_empty(&tsk->cg_list)) { write_lock(&css_set_lock); if (!list_empty(&tsk->cg_list)) list_del_init(&tsk->cg_list); write_unlock(&css_set_lock); } task_lock(tsk); cg = tsk->cgroups; tsk->cgroups = &init_css_set; if (run_callbacks && need_forkexit_callback) { for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; if (ss->exit) { struct cgroup *old_cgrp = rcu_dereference_raw(cg->subsys[i])->cgroup; struct cgroup *cgrp = task_cgroup(tsk, i); ss->exit(cgrp, old_cgrp, tsk); } } } task_unlock(tsk); if (cg) put_css_set(cg); } int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task) { int ret; struct cgroup *target; if (cgrp == dummytop) return 1; target = task_cgroup_from_root(task, cgrp->root); while (cgrp != target && cgrp!= cgrp->top_cgroup) cgrp = cgrp->parent; ret = (cgrp == target); return ret; } static void check_for_release(struct cgroup *cgrp) { if (cgroup_is_releasable(cgrp) && !atomic_read(&cgrp->count) && list_empty(&cgrp->children) && !cgroup_has_css_refs(cgrp)) { int need_schedule_work = 0; raw_spin_lock(&release_list_lock); if (!cgroup_is_removed(cgrp) && list_empty(&cgrp->release_list)) { list_add(&cgrp->release_list, &release_list); need_schedule_work = 1; } raw_spin_unlock(&release_list_lock); if (need_schedule_work) schedule_work(&release_agent_work); } } void __css_get(struct cgroup_subsys_state *css, int count) { atomic_add(count, &css->refcnt); set_bit(CGRP_RELEASABLE, &css->cgroup->flags); } EXPORT_SYMBOL_GPL(__css_get); void __css_put(struct cgroup_subsys_state *css, int count) { struct cgroup *cgrp = css->cgroup; int val; rcu_read_lock(); val = atomic_sub_return(count, &css->refcnt); if (val == 1) { check_for_release(cgrp); cgroup_wakeup_rmdir_waiter(cgrp); } rcu_read_unlock(); WARN_ON_ONCE(val < 1); } EXPORT_SYMBOL_GPL(__css_put); static void cgroup_release_agent(struct work_struct *work) { BUG_ON(work != &release_agent_work); mutex_lock(&cgroup_mutex); raw_spin_lock(&release_list_lock); while (!list_empty(&release_list)) { char *argv[3], *envp[3]; int i; char *pathbuf = NULL, *agentbuf = NULL; struct cgroup *cgrp = list_entry(release_list.next, struct cgroup, release_list); list_del_init(&cgrp->release_list); raw_spin_unlock(&release_list_lock); pathbuf = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!pathbuf) goto continue_free; if (cgroup_path(cgrp, pathbuf, PAGE_SIZE) < 0) goto continue_free; agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL); if (!agentbuf) goto continue_free; i = 0; argv[i++] = agentbuf; argv[i++] = pathbuf; argv[i] = NULL; i = 0; envp[i++] = "HOME=/"; envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; envp[i] = NULL; mutex_unlock(&cgroup_mutex); call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC); mutex_lock(&cgroup_mutex); continue_free: kfree(pathbuf); kfree(agentbuf); raw_spin_lock(&release_list_lock); } raw_spin_unlock(&release_list_lock); mutex_unlock(&cgroup_mutex); } static int __init cgroup_disable(char *str) { int i; char *token; while ((token = strsep(&str, ",")) != NULL) { if (!*token) continue; for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; if (!strcmp(token, ss->name)) { ss->disabled = 1; printk(KERN_INFO "Disabling %s control group" " subsystem\n", ss->name); break; } } } return 1; } __setup("cgroup_disable=", cgroup_disable); unsigned short css_id(struct cgroup_subsys_state *css) { struct css_id *cssid; cssid = rcu_dereference_check(css->id, atomic_read(&css->refcnt)); if (cssid) return cssid->id; return 0; } EXPORT_SYMBOL_GPL(css_id); unsigned short css_depth(struct cgroup_subsys_state *css) { struct css_id *cssid; cssid = rcu_dereference_check(css->id, atomic_read(&css->refcnt)); if (cssid) return cssid->depth; return 0; } EXPORT_SYMBOL_GPL(css_depth); /** * css_is_ancestor - test "root" css is an ancestor of "child" * @child: the css to be tested. * @root: the css supporsed to be an ancestor of the child. * * Returns true if "root" is an ancestor of "child" in its hierarchy. Because * this function reads css->id, the caller must hold rcu_read_lock(). * But, considering usual usage, the csses should be valid objects after test. * Assuming that the caller will do some action to the child if this returns * returns true, the caller must take "child";s reference count. * If "child" is valid object and this returns true, "root" is valid, too. */ bool css_is_ancestor(struct cgroup_subsys_state *child, const struct cgroup_subsys_state *root) { struct css_id *child_id; struct css_id *root_id; child_id = rcu_dereference(child->id); if (!child_id) return false; root_id = rcu_dereference(root->id); if (!root_id) return false; if (child_id->depth < root_id->depth) return false; if (child_id->stack[root_id->depth] != root_id->id) return false; return true; } void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css) { struct css_id *id = css->id; if (!id) return; BUG_ON(!ss->use_id); rcu_assign_pointer(id->css, NULL); rcu_assign_pointer(css->id, NULL); spin_lock(&ss->id_lock); idr_remove(&ss->idr, id->id); spin_unlock(&ss->id_lock); kfree_rcu(id, rcu_head); } EXPORT_SYMBOL_GPL(free_css_id); static struct css_id *get_new_cssid(struct cgroup_subsys *ss, int depth) { struct css_id *newid; int myid, error, size; BUG_ON(!ss->use_id); size = sizeof(*newid) + sizeof(unsigned short) * (depth + 1); newid = kzalloc(size, GFP_KERNEL); if (!newid) return ERR_PTR(-ENOMEM); if (unlikely(!idr_pre_get(&ss->idr, GFP_KERNEL))) { error = -ENOMEM; goto err_out; } spin_lock(&ss->id_lock); error = idr_get_new_above(&ss->idr, newid, 1, &myid); spin_unlock(&ss->id_lock); if (error) { error = -ENOSPC; goto err_out; } if (myid > CSS_ID_MAX) goto remove_idr; newid->id = myid; newid->depth = depth; return newid; remove_idr: error = -ENOSPC; spin_lock(&ss->id_lock); idr_remove(&ss->idr, myid); spin_unlock(&ss->id_lock); err_out: kfree(newid); return ERR_PTR(error); } static int __init_or_module cgroup_init_idr(struct cgroup_subsys *ss, struct cgroup_subsys_state *rootcss) { struct css_id *newid; spin_lock_init(&ss->id_lock); idr_init(&ss->idr); newid = get_new_cssid(ss, 0); if (IS_ERR(newid)) return PTR_ERR(newid); newid->stack[0] = newid->id; newid->css = rootcss; rootcss->id = newid; return 0; } static int alloc_css_id(struct cgroup_subsys *ss, struct cgroup *parent, struct cgroup *child) { int subsys_id, i, depth = 0; struct cgroup_subsys_state *parent_css, *child_css; struct css_id *child_id, *parent_id; subsys_id = ss->subsys_id; parent_css = parent->subsys[subsys_id]; child_css = child->subsys[subsys_id]; parent_id = parent_css->id; depth = parent_id->depth + 1; child_id = get_new_cssid(ss, depth); if (IS_ERR(child_id)) return PTR_ERR(child_id); for (i = 0; i < depth; i++) child_id->stack[i] = parent_id->stack[i]; child_id->stack[depth] = child_id->id; rcu_assign_pointer(child_css->id, child_id); return 0; } struct cgroup_subsys_state *css_lookup(struct cgroup_subsys *ss, int id) { struct css_id *cssid = NULL; BUG_ON(!ss->use_id); cssid = idr_find(&ss->idr, id); if (unlikely(!cssid)) return NULL; return rcu_dereference(cssid->css); } EXPORT_SYMBOL_GPL(css_lookup); struct cgroup_subsys_state * css_get_next(struct cgroup_subsys *ss, int id, struct cgroup_subsys_state *root, int *foundid) { struct cgroup_subsys_state *ret = NULL; struct css_id *tmp; int tmpid; int rootid = css_id(root); int depth = css_depth(root); if (!rootid) return NULL; BUG_ON(!ss->use_id); WARN_ON_ONCE(!rcu_read_lock_held()); tmpid = id; while (1) { tmp = idr_get_next(&ss->idr, &tmpid); if (!tmp) break; if (tmp->depth >= depth && tmp->stack[depth] == rootid) { ret = rcu_dereference(tmp->css); if (ret) { *foundid = tmpid; break; } } tmpid = tmpid + 1; } return ret; } struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id) { struct cgroup *cgrp; struct inode *inode; struct cgroup_subsys_state *css; inode = f->f_dentry->d_inode; if (inode->i_op != &cgroup_dir_inode_operations) return ERR_PTR(-EBADF); if (id < 0 || id >= CGROUP_SUBSYS_COUNT) return ERR_PTR(-EINVAL); cgrp = __d_cgrp(f->f_dentry); css = cgrp->subsys[id]; return css ? css : ERR_PTR(-ENOENT); } #ifdef CONFIG_CGROUP_DEBUG static struct cgroup_subsys_state *debug_create(struct cgroup *cont) { struct cgroup_subsys_state *css = kzalloc(sizeof(*css), GFP_KERNEL); if (!css) return ERR_PTR(-ENOMEM); return css; } static void debug_destroy(struct cgroup *cont) { kfree(cont->subsys[debug_subsys_id]); } static u64 cgroup_refcount_read(struct cgroup *cont, struct cftype *cft) { return atomic_read(&cont->count); } static u64 debug_taskcount_read(struct cgroup *cont, struct cftype *cft) { return cgroup_task_count(cont); } static u64 current_css_set_read(struct cgroup *cont, struct cftype *cft) { return (u64)(unsigned long)current->cgroups; } static u64 current_css_set_refcount_read(struct cgroup *cont, struct cftype *cft) { u64 count; rcu_read_lock(); count = atomic_read(¤t->cgroups->refcount); rcu_read_unlock(); return count; } static int current_css_set_cg_links_read(struct cgroup *cont, struct cftype *cft, struct seq_file *seq) { struct cg_cgroup_link *link; struct css_set *cg; read_lock(&css_set_lock); rcu_read_lock(); cg = rcu_dereference(current->cgroups); list_for_each_entry(link, &cg->cg_links, cg_link_list) { struct cgroup *c = link->cgrp; const char *name; if (c->dentry) name = c->dentry->d_name.name; else name = "?"; seq_printf(seq, "Root %d group %s\n", c->root->hierarchy_id, name); } rcu_read_unlock(); read_unlock(&css_set_lock); return 0; } #define MAX_TASKS_SHOWN_PER_CSS 25 static int cgroup_css_links_read(struct cgroup *cont, struct cftype *cft, struct seq_file *seq) { struct cg_cgroup_link *link; read_lock(&css_set_lock); list_for_each_entry(link, &cont->css_sets, cgrp_link_list) { struct css_set *cg = link->cg; struct task_struct *task; int count = 0; seq_printf(seq, "css_set %p\n", cg); list_for_each_entry(task, &cg->tasks, cg_list) { if (count++ > MAX_TASKS_SHOWN_PER_CSS) { seq_puts(seq, " ...\n"); break; } else { seq_printf(seq, " task %d\n", task_pid_vnr(task)); } } } read_unlock(&css_set_lock); return 0; } static u64 releasable_read(struct cgroup *cgrp, struct cftype *cft) { return test_bit(CGRP_RELEASABLE, &cgrp->flags); } static struct cftype debug_files[] = { { .name = "cgroup_refcount", .read_u64 = cgroup_refcount_read, }, { .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", .read_seq_string = current_css_set_cg_links_read, }, { .name = "cgroup_css_links", .read_seq_string = cgroup_css_links_read, }, { .name = "releasable", .read_u64 = releasable_read, }, }; static int debug_populate(struct cgroup_subsys *ss, struct cgroup *cont) { return cgroup_add_files(cont, ss, debug_files, ARRAY_SIZE(debug_files)); } struct cgroup_subsys debug_subsys = { .name = "debug", .create = debug_create, .destroy = debug_destroy, .populate = debug_populate, .subsys_id = debug_subsys_id, }; #endif