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Commit 9d403e99 authored by Tejun Heo's avatar Tejun Heo
Browse files

cgroup: combine css handling loops in cgroup_create() 



Now that css operations in cgroup_create() are back-to-back, there
isn't much point in allocating css's in one loop and onlining them in
another.  Merge the two loops so that a css is allocated and onlined
on each iteration.

css_ar[] is no longer necessary and replaced with a single pointer.
This also simplifies the error handling path.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarLi Zefan <lizefan@huawei.com>
parent 0d80255e

kernel/cgroup.c

+7 −18
Original line number Diff line number Diff line
@@ -4084,7 +4084,7 @@ static void offline_css(struct cgroup_subsys_state *css) 
static long cgroup_create(struct cgroup *parent, struct dentry *dentry,

			     umode_t mode)

{

	struct cgroup_subsys_state *css_ar[CGROUP_SUBSYS_COUNT] = { };

	struct cgroup_subsys_state *css = NULL;

	struct cgroup *cgrp;

	struct cgroup_name *name;

	struct cgroupfs_root *root = parent->root;
@@ -4173,26 +4173,20 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, 
	if (err)

		goto err_destroy;



	/* let's create and online css's */

	for_each_root_subsys(root, ss) {

		struct cgroup_subsys_state *css;



		css = ss->css_alloc(cgroup_css(parent, ss));

		if (IS_ERR(css)) {

			err = PTR_ERR(css);

			css = NULL;

			goto err_destroy;

		}

		css_ar[ss->subsys_id] = css;



		err = percpu_ref_init(&css->refcnt, css_release);

		if (err)

			goto err_destroy;



		init_css(css, ss, cgrp);

	}



	/* creation succeeded, notify subsystems */

	for_each_root_subsys(root, ss) {

		struct cgroup_subsys_state *css = css_ar[ss->subsys_id];



		err = cgroup_populate_dir(cgrp, 1 << ss->subsys_id);

		if (err)
@@ -4202,12 +4196,11 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, 
		if (err)

			goto err_destroy;



		/* each css holds a ref to the cgroup's dentry and parent css */

		dget(dentry);

		css_get(css->parent);



		/* mark it consumed for error path */

		css_ar[ss->subsys_id] = NULL;

		css = NULL;



		if (ss->broken_hierarchy && !ss->warned_broken_hierarchy &&

		    parent->parent) {
@@ -4237,13 +4230,9 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, 
	return err;



err_destroy:

	for_each_root_subsys(root, ss) {

		struct cgroup_subsys_state *css = css_ar[ss->subsys_id];



	if (css) {

		percpu_ref_cancel_init(&css->refcnt);

			ss->css_free(css);

		}

		css->ss->css_free(css);

	}

	cgroup_destroy_locked(cgrp);

	mutex_unlock(&cgroup_mutex);