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Commit 03970d3c authored by Tejun Heo's avatar Tejun Heo
Browse files

cgroup: use cgroup_apply_enable_control() in cgroup creation path 



cgroup_create() manually updates control masks and creates child csses
which cgroup_mkdir() then manually populates.  Both can be simplified
by using cgroup_apply_enable_control() and friends.  The only catch is
that it calls css_populate_dir() with NULL cgroup->kn during
cgroup_create().  This is worked around by making the function noop on
NULL kn.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarZefan Li <lizefan@huawei.com>
parent 945ba199

kernel/cgroup.c

+14 −24
Original line number Diff line number Diff line
@@ -1490,7 +1490,7 @@ static int css_populate_dir(struct cgroup_subsys_state *css, 
	struct cftype *cfts, *failed_cfts;

	int ret;



	if (css->flags & CSS_VISIBLE)

	if ((css->flags & CSS_VISIBLE) || !cgrp->kn)

		return 0;



	if (!css->ss) {
@@ -5042,10 +5042,9 @@ static struct cgroup_subsys_state *css_create(struct cgroup *cgrp, 
static struct cgroup *cgroup_create(struct cgroup *parent)

{

	struct cgroup_root *root = parent->root;

	struct cgroup_subsys *ss;

	struct cgroup *cgrp, *tcgrp;

	int level = parent->level + 1;

	int ssid, ret;

	int ret;



	/* allocate the cgroup and its ID, 0 is reserved for the root */

	cgrp = kzalloc(sizeof(*cgrp) +
@@ -5095,25 +5094,19 @@ static struct cgroup *cgroup_create(struct cgroup *parent) 
	 */

	cgroup_idr_replace(&root->cgroup_idr, cgrp, cgrp->id);



	/* create the csses */

	do_each_subsys_mask(ss, ssid, cgroup_ss_mask(cgrp)) {

		struct cgroup_subsys_state *css;



		css = css_create(cgrp, ss);

		if (IS_ERR(css)) {

			ret = PTR_ERR(css);

			goto out_destroy;

		}

	} while_each_subsys_mask();



	/*

	 * On the default hierarchy, a child doesn't automatically inherit

	 * subtree_control from the parent.  Each is configured manually.

	 */

	if (!cgroup_on_dfl(cgrp)) {

	if (!cgroup_on_dfl(cgrp))

		cgrp->subtree_control = cgroup_control(cgrp);

		cgroup_refresh_subtree_ss_mask(cgrp);

	}



	cgroup_propagate_control(cgrp);



	/* @cgrp doesn't have dir yet so the following will only create csses */

	ret = cgroup_apply_control_enable(cgrp);

	if (ret)

		goto out_destroy;



	return cgrp;
@@ -5131,9 +5124,8 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, 
			umode_t mode)

{

	struct cgroup *parent, *cgrp;

	struct cgroup_subsys *ss;

	struct kernfs_node *kn;

	int ssid, ret;

	int ret;



	/* do not accept '\n' to prevent making /proc/<pid>/cgroup unparsable */

	if (strchr(name, '\n'))
@@ -5171,11 +5163,9 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, 
	if (ret)

		goto out_destroy;



	do_each_subsys_mask(ss, ssid, cgroup_control(cgrp)) {

		ret = css_populate_dir(cgroup_css(cgrp, ss), NULL);

	ret = cgroup_apply_control_enable(cgrp);

	if (ret)

		goto out_destroy;

	} while_each_subsys_mask();



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

	kernfs_activate(kn);