1 files changed, 79 insertions, 61 deletions

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index d34c170f87ef..228dd9ae708b 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -1989,48 +1989,55 @@ out:
         return ret;
 }
 
-static struct dentry *cgroup_mount(struct file_system_type *fs_type,
-                         int flags, const char *unused_dev_name,
-                         void *data)
+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)
 {
-        bool is_v2 = fs_type == &cgroup2_fs_type;
-        struct super_block *pinned_sb = NULL;
-        struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;
-        struct cgroup_subsys *ss;
-        struct cgroup_root *root;
-        struct cgroup_sb_opts opts;
         struct dentry *dentry;
-        int ret;
-        int i;
         bool new_sb;
 
-        get_cgroup_ns(ns);
-
-        /* Check if the caller has permission to mount. */
-        if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) {
-                put_cgroup_ns(ns);
-                return ERR_PTR(-EPERM);
-        }
+        dentry = kernfs_mount(fs_type, flags, root->kf_root, magic, &new_sb);
 
         /*
-         * The first time anyone tries to mount a cgroup, enable the list
-         * linking each css_set to its tasks and fix up all existing tasks.
+         * In non-init cgroup namespace, instead of root cgroup's dentry,
+         * we return the dentry corresponding to the cgroupns->root_cgrp.
          */
-        if (!use_task_css_set_links)
-                cgroup_enable_task_cg_lists();
+        if (!IS_ERR(dentry) && ns != &init_cgroup_ns) {
+                struct dentry *nsdentry;
+                struct cgroup *cgrp;
 
-        if (is_v2) {
-                if (data) {
-                        pr_err("cgroup2: unknown option \"%s\"\n", (char *)data);
-                        put_cgroup_ns(ns);
-                        return ERR_PTR(-EINVAL);
-                }
-                cgrp_dfl_visible = true;
-                root = &cgrp_dfl_root;
-                cgroup_get(&root->cgrp);
-                goto out_mount;
+                mutex_lock(&cgroup_mutex);
+                spin_lock_irq(&css_set_lock);
+
+                cgrp = cset_cgroup_from_root(ns->root_cset, root);
+
+                spin_unlock_irq(&css_set_lock);
+                mutex_unlock(&cgroup_mutex);
+
+                nsdentry = kernfs_node_dentry(cgrp->kn, dentry->d_sb);
+                dput(dentry);
+                dentry = nsdentry;
         }
 
+        if (IS_ERR(dentry) || !new_sb)
+                cgroup_put(&root->cgrp);
+
+        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 */
@@ -2152,47 +2159,58 @@ out_free:
         kfree(opts.release_agent);
         kfree(opts.name);
 
-        if (ret) {
-                put_cgroup_ns(ns);
+        if (ret)
                 return ERR_PTR(ret);
-        }
-out_mount:
-        dentry = kernfs_mount(fs_type, flags, root->kf_root,
-                              is_v2 ? CGROUP2_SUPER_MAGIC : CGROUP_SUPER_MAGIC,
-                              &new_sb);
+
+        dentry = cgroup_do_mount(&cgroup_fs_type, flags, root,
+                                 CGROUP_SUPER_MAGIC, ns);
 
         /*
-         * In non-init cgroup namespace, instead of root cgroup's
-         * dentry, we return the dentry corresponding to the
-         * cgroupns->root_cgrp.
+         * 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 (!IS_ERR(dentry) && ns != &init_cgroup_ns) {
-                struct dentry *nsdentry;
-                struct cgroup *cgrp;
+        if (pinned_sb)
+                deactivate_super(pinned_sb);
 
-                mutex_lock(&cgroup_mutex);
-                spin_lock_irq(&css_set_lock);
+        return dentry;
+}
 
-                cgrp = cset_cgroup_from_root(ns->root_cset, root);
+static struct dentry *cgroup_mount(struct file_system_type *fs_type,
+                         int flags, const char *unused_dev_name,
+                         void *data)
+{
+        struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;
+        struct dentry *dentry;
 
-                spin_unlock_irq(&css_set_lock);
-                mutex_unlock(&cgroup_mutex);
+        get_cgroup_ns(ns);
 
-                nsdentry = kernfs_node_dentry(cgrp->kn, dentry->d_sb);
-                dput(dentry);
-                dentry = nsdentry;
+        /* Check if the caller has permission to mount. */
+        if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) {
+                put_cgroup_ns(ns);
+                return ERR_PTR(-EPERM);
         }
 
-        if (IS_ERR(dentry) || !new_sb)
-                cgroup_put(&root->cgrp);
-
         /*
-         * If @pinned_sb, we're reusing an existing root and holding an
-         * extra ref on its sb.  Mount is complete.  Put the extra ref.
+         * The first time anyone tries to mount a cgroup, enable the list
+         * linking each css_set to its tasks and fix up all existing tasks.
          */
-        if (pinned_sb) {
-                WARN_ON(new_sb);
-                deactivate_super(pinned_sb);
+        if (!use_task_css_set_links)
+                cgroup_enable_task_cg_lists();
+
+        if (fs_type == &cgroup2_fs_type) {
+                if (data) {
+                        pr_err("cgroup2: unknown option \"%s\"\n", (char *)data);
+                        put_cgroup_ns(ns);
+                        return ERR_PTR(-EINVAL);
+                }
+                cgrp_dfl_visible = true;
+                cgroup_get(&cgrp_dfl_root.cgrp);
+
+                dentry = cgroup_do_mount(&cgroup2_fs_type, flags, &cgrp_dfl_root,
+                                         CGROUP2_SUPER_MAGIC, ns);
+        } else {
+                dentry = cgroup1_mount(&cgroup_fs_type, flags, data,
+                                       CGROUP_SUPER_MAGIC, ns);
         }
 
         put_cgroup_ns(ns);