cgroup: reorder operations in cgroup_mkdir()

Currently, operations to initialize internal objects and create
interface directory and files are intermixed in cgroup_mkdir().  We're
in the process of refactoring cgroup and css management paths to
separate them out to eventually allow cgroups which aren't visible
through cgroup fs.

This patch reorders operations inside cgroup_mkdir() so that interface
directory and file handling comes after internal object
initialization.  This will enable further refactoring.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Zefan Li <lizefan@huawei.com>

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index a9a53ca942f3bbcb9afd4e441564d02f98706161..a6d484a667aa485ca7cf330fb6a1892c9f548f9c 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4945,20 +4945,6 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
        if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &parent->flags))
                set_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags);
 
-       /* create the directory */
-       kn = kernfs_create_dir(parent->kn, name, mode, cgrp);
-       if (IS_ERR(kn)) {
-               ret = PTR_ERR(kn);
-               goto out_free_id;
-       }
-       cgrp->kn = kn;
-
-       /*
-        * This extra ref will be put in cgroup_free_fn() and guarantees
-        * that @cgrp->kn is always accessible.
-        */
-       kernfs_get(kn);
-
        cgrp->self.serial_nr = css_serial_nr_next++;
 
        /* allocation complete, commit to creation */
@@ -4972,15 +4958,7 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
         */
        cgroup_idr_replace(&root->cgroup_idr, cgrp, cgrp->id);
 
-       ret = cgroup_kn_set_ugid(kn);
-       if (ret)
-               goto out_destroy;
-
-       ret = css_populate_dir(&cgrp->self, NULL);
-       if (ret)
-               goto out_destroy;
-
-       /* let's create and online css's */
+       /* create the csses */
        do_each_subsys_mask(ss, ssid, parent->subtree_ss_mask) {
                struct cgroup_subsys_state *css;
 
@@ -4989,12 +4967,6 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
                        ret = PTR_ERR(css);
                        goto out_destroy;
                }
-
-               if (parent->subtree_control & (1 << ssid)) {
-                       ret = css_populate_dir(css, NULL);
-                       if (ret)
-                               goto out_destroy;
-               }
        } while_each_subsys_mask();
 
        /*
@@ -5006,13 +4978,40 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
                cgroup_refresh_subtree_ss_mask(cgrp);
        }
 
+       /* create the directory */
+       kn = kernfs_create_dir(parent->kn, name, mode, cgrp);
+       if (IS_ERR(kn)) {
+               ret = PTR_ERR(kn);
+               goto out_destroy;
+       }
+       cgrp->kn = kn;
+
+       /*
+        * This extra ref will be put in cgroup_free_fn() and guarantees
+        * that @cgrp->kn is always accessible.
+        */
+       kernfs_get(kn);
+
+       ret = cgroup_kn_set_ugid(kn);
+       if (ret)
+               goto out_destroy;
+
+       ret = css_populate_dir(&cgrp->self, NULL);
+       if (ret)
+               goto out_destroy;
+
+       do_each_subsys_mask(ss, ssid, parent->subtree_control) {
+               ret = css_populate_dir(cgroup_css(cgrp, ss), NULL);
+               if (ret)
+                       goto out_destroy;
+       } while_each_subsys_mask();
+
+       /* let's create and online css's */
        kernfs_activate(kn);
 
        ret = 0;
        goto out_unlock;
 
-out_free_id:
-       cgroup_idr_remove(&root->cgroup_idr, cgrp->id);
 out_cancel_ref:
        percpu_ref_exit(&cgrp->self.refcnt);
 out_free_cgrp: