diff options
Diffstat (limited to 'kernel/cgroup/cgroup.c')
-rw-r--r-- | kernel/cgroup/cgroup.c | 410 |
1 files changed, 10 insertions, 400 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index de6a2ac41d0b..4be306510aff 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -31,7 +31,6 @@ #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> @@ -49,7 +48,6 @@ #include <linux/hashtable.h> #include <linux/idr.h> #include <linux/kthread.h> -#include <linux/delay.h> #include <linux/atomic.h> #include <linux/cpuset.h> #include <linux/proc_ns.h> @@ -1078,7 +1076,7 @@ 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); @@ -1232,7 +1230,6 @@ struct cgroup *task_cgroup_from_root(struct task_struct *task, * update of a tasks cgroup pointer by cgroup_attach_task() */ -static struct kernfs_syscall_ops cgroup1_kf_syscall_ops; static struct kernfs_syscall_ops cgroup_kf_syscall_ops; static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft, @@ -1540,8 +1537,8 @@ 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; @@ -1567,232 +1564,6 @@ static int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node, return len; } -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; -} - -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 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; -} - static int cgroup_remount(struct kernfs_root *kf_root, int *flags, char *data) { pr_err("remount is not allowed\n"); @@ -1877,8 +1648,7 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp) INIT_WORK(&cgrp->release_agent_work, cgroup_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; @@ -1897,7 +1667,7 @@ 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; @@ -1994,10 +1764,9 @@ out: return ret; } -static struct dentry *cgroup_do_mount(struct file_system_type *fs_type, - int flags, struct cgroup_root *root, - unsigned long magic, - struct cgroup_namespace *ns) +struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags, + struct cgroup_root *root, unsigned long magic, + struct cgroup_namespace *ns) { struct dentry *dentry; bool new_sb; @@ -2031,155 +1800,6 @@ static struct dentry *cgroup_do_mount(struct file_system_type *fs_type, return dentry; } -static 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 struct dentry *cgroup_mount(struct file_system_type *fs_type, int flags, const char *unused_dev_name, void *data) @@ -4587,8 +4207,7 @@ out_destroy: 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; @@ -4800,7 +4419,7 @@ 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; @@ -4818,15 +4437,6 @@ static int cgroup_rmdir(struct kernfs_node *kn) return ret; } -static struct kernfs_syscall_ops cgroup1_kf_syscall_ops = { - .remount_fs = cgroup1_remount, - .show_options = cgroup1_show_options, - .rename = cgroup1_rename, - .mkdir = cgroup_mkdir, - .rmdir = cgroup_rmdir, - .show_path = cgroup_show_path, -}; - static struct kernfs_syscall_ops cgroup_kf_syscall_ops = { .remount_fs = cgroup_remount, .mkdir = cgroup_mkdir, |