Commit 28fd6f30 authored by Tejun Heo's avatar Tejun Heo
Browse files

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: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarLi Zefan <lizefan@huawei.com>
parent 2243076a

kernel/cgroup.c

+5 −25
Original line number Diff line number Diff line
@@ -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);

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