cgroup: open-code cgroup_create_dir()

The operation order of cgroup creation is about to change and
cgroup_create_dir() is more of a hindrance than a proper abstraction.
Open-code it by moving the parent nlink adjustment next to self nlink
adjustment in cgroup_create_file() and the rest to cgroup_create().

This patch doesn't introduce any behavior change.

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

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index ed0e177..b042673 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2652,6 +2652,7 @@ static int cgroup_create_file(struct dentry *dentry, umode_t mode,
 
                /* start off with i_nlink == 2 (for "." entry) */
                inc_nlink(inode);
+               inc_nlink(dentry->d_parent->d_inode);
 
                /* start with the directory inode held, so that we can
                 * populate it without racing with another mkdir */
@@ -2666,30 +2667,6 @@ static int cgroup_create_file(struct dentry *dentry, umode_t mode,
        return 0;
 }
 
-/*
- * cgroup_create_dir - create a directory for an object.
- * @cgrp: the cgroup we create the directory for. It must have a valid
- *        ->parent field. And we are going to fill its ->dentry field.
- * @dentry: dentry of the new cgroup
- * @mode: mode to set on new directory.
- */
-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);
-       }
-
-       return error;
-}
-
 /**
  * cgroup_file_mode - deduce file mode of a control file
  * @cft: the control file in question
@@ -4138,10 +4115,13 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
        list_add_tail_rcu(&cgrp->sibling, &cgrp->parent->children);
        root->number_of_cgroups++;
 
-       err = cgroup_create_dir(cgrp, dentry, mode);
+       err = cgroup_create_file(dentry, S_IFDIR | mode, sb);
        if (err < 0)
                goto err_remove;
 
+       dentry->d_fsdata = cgrp;
+       rcu_assign_pointer(cgrp->dentry, dentry);
+
        for_each_subsys(root, ss) {
                /* each css holds a ref to the cgroup's dentry */
                dget(dentry);