cgroup: move v1 mount functions to kernel/cgroup/cgroup-v1.c
authorTejun Heo <tj@kernel.org>
Tue, 27 Dec 2016 19:49:08 +0000 (14:49 -0500)
committerTejun Heo <tj@kernel.org>
Tue, 27 Dec 2016 19:49:08 +0000 (14:49 -0500)
Now that the v1 mount code is split into separate functions, move them
to kernel/cgroup/cgroup-v1.c along with the mount option handling
code.  As this puts all v1-only kernfs_syscall_ops in cgroup-v1.c,
move cgroup1_kf_syscall_ops to cgroup-v1.c too.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Acked-by: Zefan Li <lizefan@huawei.com>
kernel/cgroup/cgroup-internal.h
kernel/cgroup/cgroup-v1.c
kernel/cgroup/cgroup.c

index 5790e5ff9a0f80d26ce200861231aa8847371598..710edeeb1f9f133b4c0a68561f565fa98f76cf7f 100644 (file)
@@ -26,6 +26,16 @@ struct cgrp_cset_link {
        struct list_head        cgrp_link;
 };
 
+struct cgroup_sb_opts {
+       u16 subsys_mask;
+       unsigned int flags;
+       char *release_agent;
+       bool cpuset_clone_children;
+       char *name;
+       /* User explicitly requested empty subsystem */
+       bool none;
+};
+
 extern struct mutex cgroup_mutex;
 extern spinlock_t css_set_lock;
 extern struct cgroup_subsys *cgroup_subsys[];
@@ -66,7 +76,13 @@ void cgroup_kn_unlock(struct kernfs_node *kn);
 int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
                          struct cgroup_namespace *ns);
 
+void cgroup_free_root(struct cgroup_root *root);
+void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts);
+int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask);
 int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
+struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags,
+                              struct cgroup_root *root, unsigned long magic,
+                              struct cgroup_namespace *ns);
 
 bool cgroup_may_migrate_to(struct cgroup *dst_cgrp);
 void cgroup_migrate_finish(struct list_head *preloaded_csets);
@@ -86,18 +102,24 @@ ssize_t cgroup_procs_write(struct kernfs_open_file *of, char *buf, size_t nbytes
 
 void cgroup_lock_and_drain_offline(struct cgroup *cgrp);
 
+int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode);
+int cgroup_rmdir(struct kernfs_node *kn);
+int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
+                    struct kernfs_root *kf_root);
+
 /*
  * cgroup-v1.c
  */
-extern spinlock_t release_agent_path_lock;
 extern struct cftype cgroup_legacy_base_files[];
 extern const struct file_operations proc_cgroupstats_operations;
+extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops;
 
 bool cgroup_ssid_no_v1(int ssid);
 void cgroup_pidlist_destroy_all(struct cgroup *cgrp);
-int cgroup1_rename(struct kernfs_node *kn, struct kernfs_node *new_parent,
-                  const char *new_name_str);
 void cgroup_release_agent(struct work_struct *work);
 void check_for_release(struct cgroup *cgrp);
+struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags,
+                            void *data, unsigned long magic,
+                            struct cgroup_namespace *ns);
 
 #endif /* __CGROUP_INTERNAL_H */
index 0b2c24f0b3102c1bb026b7aff56169144ca7f5ce..ae240c0d33cb5c0ef506a11ac32d53d622c5af5e 100644 (file)
@@ -1,7 +1,9 @@
 #include "cgroup-internal.h"
 
+#include <linux/ctype.h>
 #include <linux/kmod.h>
 #include <linux/sort.h>
+#include <linux/delay.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
@@ -32,7 +34,7 @@ static struct workqueue_struct *cgroup_pidlist_destroy_wq;
  * Protects cgroup_subsys->release_agent_path.  Modifying it also requires
  * cgroup_mutex.  Reading requires either cgroup_mutex or this spinlock.
  */
-DEFINE_SPINLOCK(release_agent_path_lock);
+static DEFINE_SPINLOCK(release_agent_path_lock);
 
 bool cgroup_ssid_no_v1(int ssid)
 {
@@ -800,8 +802,8 @@ out_free:
 /*
  * cgroup_rename - Only allow simple rename of directories in place.
  */
-int cgroup1_rename(struct kernfs_node *kn, struct kernfs_node *new_parent,
-                  const char *new_name_str)
+static int cgroup1_rename(struct kernfs_node *kn, struct kernfs_node *new_parent,
+                         const char *new_name_str)
 {
        struct cgroup *cgrp = kn->priv;
        int ret;
@@ -832,6 +834,379 @@ int cgroup1_rename(struct kernfs_node *kn, struct kernfs_node *new_parent,
        return ret;
 }
 
+static int cgroup1_show_options(struct seq_file *seq, struct kernfs_root *kf_root)
+{
+       struct cgroup_root *root = cgroup_root_from_kf(kf_root);
+       struct cgroup_subsys *ss;
+       int ssid;
+
+       for_each_subsys(ss, ssid)
+               if (root->subsys_mask & (1 << ssid))
+                       seq_show_option(seq, ss->legacy_name, NULL);
+       if (root->flags & CGRP_ROOT_NOPREFIX)
+               seq_puts(seq, ",noprefix");
+       if (root->flags & CGRP_ROOT_XATTR)
+               seq_puts(seq, ",xattr");
+
+       spin_lock(&release_agent_path_lock);
+       if (strlen(root->release_agent_path))
+               seq_show_option(seq, "release_agent",
+                               root->release_agent_path);
+       spin_unlock(&release_agent_path_lock);
+
+       if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags))
+               seq_puts(seq, ",clone_children");
+       if (strlen(root->name))
+               seq_show_option(seq, "name", root->name);
+       return 0;
+}
+
+static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
+{
+       char *token, *o = data;
+       bool all_ss = false, one_ss = false;
+       u16 mask = U16_MAX;
+       struct cgroup_subsys *ss;
+       int nr_opts = 0;
+       int i;
+
+#ifdef CONFIG_CPUSETS
+       mask = ~((u16)1 << cpuset_cgrp_id);
+#endif
+
+       memset(opts, 0, sizeof(*opts));
+
+       while ((token = strsep(&o, ",")) != NULL) {
+               nr_opts++;
+
+               if (!*token)
+                       return -EINVAL;
+               if (!strcmp(token, "none")) {
+                       /* Explicitly have no subsystems */
+                       opts->none = true;
+                       continue;
+               }
+               if (!strcmp(token, "all")) {
+                       /* Mutually exclusive option 'all' + subsystem name */
+                       if (one_ss)
+                               return -EINVAL;
+                       all_ss = true;
+                       continue;
+               }
+               if (!strcmp(token, "noprefix")) {
+                       opts->flags |= CGRP_ROOT_NOPREFIX;
+                       continue;
+               }
+               if (!strcmp(token, "clone_children")) {
+                       opts->cpuset_clone_children = true;
+                       continue;
+               }
+               if (!strcmp(token, "xattr")) {
+                       opts->flags |= CGRP_ROOT_XATTR;
+                       continue;
+               }
+               if (!strncmp(token, "release_agent=", 14)) {
+                       /* Specifying two release agents is forbidden */
+                       if (opts->release_agent)
+                               return -EINVAL;
+                       opts->release_agent =
+                               kstrndup(token + 14, PATH_MAX - 1, GFP_KERNEL);
+                       if (!opts->release_agent)
+                               return -ENOMEM;
+                       continue;
+               }
+               if (!strncmp(token, "name=", 5)) {
+                       const char *name = token + 5;
+                       /* Can't specify an empty name */
+                       if (!strlen(name))
+                               return -EINVAL;
+                       /* Must match [\w.-]+ */
+                       for (i = 0; i < strlen(name); i++) {
+                               char c = name[i];
+                               if (isalnum(c))
+                                       continue;
+                               if ((c == '.') || (c == '-') || (c == '_'))
+                                       continue;
+                               return -EINVAL;
+                       }
+                       /* Specifying two names is forbidden */
+                       if (opts->name)
+                               return -EINVAL;
+                       opts->name = kstrndup(name,
+                                             MAX_CGROUP_ROOT_NAMELEN - 1,
+                                             GFP_KERNEL);
+                       if (!opts->name)
+                               return -ENOMEM;
+
+                       continue;
+               }
+
+               for_each_subsys(ss, i) {
+                       if (strcmp(token, ss->legacy_name))
+                               continue;
+                       if (!cgroup_ssid_enabled(i))
+                               continue;
+                       if (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;
+}
+
+struct kernfs_syscall_ops cgroup1_kf_syscall_ops = {
+       .rename                 = cgroup1_rename,
+       .show_options           = cgroup1_show_options,
+       .remount_fs             = cgroup1_remount,
+       .mkdir                  = cgroup_mkdir,
+       .rmdir                  = cgroup_rmdir,
+       .show_path              = cgroup_show_path,
+};
+
+struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags,
+                            void *data, unsigned long magic,
+                            struct cgroup_namespace *ns)
+{
+       struct super_block *pinned_sb = NULL;
+       struct cgroup_sb_opts opts;
+       struct cgroup_root *root;
+       struct cgroup_subsys *ss;
+       struct dentry *dentry;
+       int i, ret;
+
+       cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
+
+       /* First find the desired set of subsystems */
+       ret = parse_cgroupfs_options(data, &opts);
+       if (ret)
+               goto out_unlock;
+
+       /*
+        * Destruction of cgroup root is asynchronous, so subsystems may
+        * still be dying after the previous unmount.  Let's drain the
+        * dying subsystems.  We just need to ensure that the ones
+        * unmounted previously finish dying and don't care about new ones
+        * starting.  Testing ref liveliness is good enough.
+        */
+       for_each_subsys(ss, i) {
+               if (!(opts.subsys_mask & (1 << i)) ||
+                   ss->root == &cgrp_dfl_root)
+                       continue;
+
+               if (!percpu_ref_tryget_live(&ss->root->cgrp.self.refcnt)) {
+                       mutex_unlock(&cgroup_mutex);
+                       msleep(10);
+                       ret = restart_syscall();
+                       goto out_free;
+               }
+               cgroup_put(&ss->root->cgrp);
+       }
+
+       for_each_root(root) {
+               bool name_match = false;
+
+               if (root == &cgrp_dfl_root)
+                       continue;
+
+               /*
+                * If we asked for a name then it must match.  Also, if
+                * name matches but sybsys_mask doesn't, we should fail.
+                * Remember whether name matched.
+                */
+               if (opts.name) {
+                       if (strcmp(opts.name, root->name))
+                               continue;
+                       name_match = true;
+               }
+
+               /*
+                * If we asked for subsystems (or explicitly for no
+                * subsystems) then they must match.
+                */
+               if ((opts.subsys_mask || opts.none) &&
+                   (opts.subsys_mask != root->subsys_mask)) {
+                       if (!name_match)
+                               continue;
+                       ret = -EBUSY;
+                       goto out_unlock;
+               }
+
+               if (root->flags ^ opts.flags)
+                       pr_warn("new mount options do not match the existing superblock, will be ignored\n");
+
+               /*
+                * We want to reuse @root whose lifetime is governed by its
+                * ->cgrp.  Let's check whether @root is alive and keep it
+                * that way.  As cgroup_kill_sb() can happen anytime, we
+                * want to block it by pinning the sb so that @root doesn't
+                * get killed before mount is complete.
+                *
+                * With the sb pinned, tryget_live can reliably indicate
+                * whether @root can be reused.  If it's being killed,
+                * drain it.  We can use wait_queue for the wait but this
+                * path is super cold.  Let's just sleep a bit and retry.
+                */
+               pinned_sb = kernfs_pin_sb(root->kf_root, NULL);
+               if (IS_ERR(pinned_sb) ||
+                   !percpu_ref_tryget_live(&root->cgrp.self.refcnt)) {
+                       mutex_unlock(&cgroup_mutex);
+                       if (!IS_ERR_OR_NULL(pinned_sb))
+                               deactivate_super(pinned_sb);
+                       msleep(10);
+                       ret = restart_syscall();
+                       goto out_free;
+               }
+
+               ret = 0;
+               goto out_unlock;
+       }
+
+       /*
+        * No such thing, create a new one.  name= matching without subsys
+        * specification is allowed for already existing hierarchies but we
+        * can't create new one without subsys specification.
+        */
+       if (!opts.subsys_mask && !opts.none) {
+               ret = -EINVAL;
+               goto out_unlock;
+       }
+
+       /* Hierarchies may only be created in the initial cgroup namespace. */
+       if (ns != &init_cgroup_ns) {
+               ret = -EPERM;
+               goto out_unlock;
+       }
+
+       root = kzalloc(sizeof(*root), GFP_KERNEL);
+       if (!root) {
+               ret = -ENOMEM;
+               goto out_unlock;
+       }
+
+       init_cgroup_root(root, &opts);
+
+       ret = cgroup_setup_root(root, opts.subsys_mask);
+       if (ret)
+               cgroup_free_root(root);
+
+out_unlock:
+       mutex_unlock(&cgroup_mutex);
+out_free:
+       kfree(opts.release_agent);
+       kfree(opts.name);
+
+       if (ret)
+               return ERR_PTR(ret);
+
+       dentry = cgroup_do_mount(&cgroup_fs_type, flags, root,
+                                CGROUP_SUPER_MAGIC, ns);
+
+       /*
+        * If @pinned_sb, we're reusing an existing root and holding an
+        * extra ref on its sb.  Mount is complete.  Put the extra ref.
+        */
+       if (pinned_sb)
+               deactivate_super(pinned_sb);
+
+       return dentry;
+}
+
 static int __init cgroup1_wq_init(void)
 {
        /*
index de6a2ac41d0b1e88e09a34c06a2566923299a636..4be306510aff9555c73a5240e707851cf6b7f560 100644 (file)
@@ -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,