cgroup: make cgrp_dfl_root mountable (a2dd4247) · Commits · e / devices / android_kernel_xiaomi_markw

include/linux/cgroup.h

+10 −0

Original line number	Original line	Diff line number	Diff line
	@@ -250,6 +250,9 @@ enum {
	*		*
	* - "cgroup.clone_children" is removed.		* - "cgroup.clone_children" is removed.
	*		*
			* - If mount is requested with sane_behavior but without any
			* subsystem, the default unified hierarchy is mounted.
			*
	* - cpuset: tasks will be kept in empty cpusets when hotplug happens		* - cpuset: tasks will be kept in empty cpusets when hotplug happens
	* and take masks of ancestors with non-empty cpus/mems, instead of		* and take masks of ancestors with non-empty cpus/mems, instead of
	* being moved to an ancestor.		* being moved to an ancestor.
	@@ -468,6 +471,13 @@ struct cftype {
	#endif		#endif
	};		};

			extern struct cgroup_root cgrp_dfl_root;

			static inline bool cgroup_on_dfl(const struct cgroup *cgrp)
			{
			return cgrp->root == &cgrp_dfl_root;
			}

	/*		/*
	* See the comment above CGRP_ROOT_SANE_BEHAVIOR for details. This		* See the comment above CGRP_ROOT_SANE_BEHAVIOR for details. This
	* function can be called as long as @cgrp is accessible.		* function can be called as long as @cgrp is accessible.

kernel/cgroup.c

+61 −33

Original line number	Original line	Diff line number	Diff line
	@@ -142,7 +142,13 @@ static const char *cgroup_subsys_name[] = {
	* unattached - it never has more than a single cgroup, and all tasks are		* unattached - it never has more than a single cgroup, and all tasks are
	* part of that cgroup.		* part of that cgroup.
	*/		*/
	static struct cgroup_root cgrp_dfl_root;		struct cgroup_root cgrp_dfl_root;

			/*
			* The default hierarchy always exists but is hidden until mounted for the
			* first time. This is for backward compatibility.
			*/
			static bool cgrp_dfl_root_visible;

	/* The list of hierarchy roots */		/* The list of hierarchy roots */

	@@ -999,10 +1005,22 @@ static int rebind_subsystems(struct cgroup_root *dst_root,
	return -EBUSY;		return -EBUSY;
	}		}

	if (dst_root != &cgrp_dfl_root) {
	ret = cgroup_populate_dir(&dst_root->cgrp, ss_mask);		ret = cgroup_populate_dir(&dst_root->cgrp, ss_mask);
	if (ret)		if (ret) {
			if (dst_root != &cgrp_dfl_root)
	return ret;		return ret;

			/*
			* Rebinding back to the default root is not allowed to
			* fail. Using both default and non-default roots should
			* be rare. Moving subsystems back and forth even more so.
			* Just warn about it and continue.
			*/
			if (cgrp_dfl_root_visible) {
			pr_warning("cgroup: failed to create files (%d) while rebinding 0x%lx to default root\n",
			ret, ss_mask);
			pr_warning("cgroup: you may retry by moving them to a different hierarchy and unbinding\n");
			}
	}		}

	/*		/*
	@@ -1011,7 +1029,7 @@ static int rebind_subsystems(struct cgroup_root *dst_root,
	*/		*/
	mutex_unlock(&cgroup_mutex);		mutex_unlock(&cgroup_mutex);
	for_each_subsys(ss, ssid)		for_each_subsys(ss, ssid)
	if ((ss_mask & (1 << ssid)) && ss->root != &cgrp_dfl_root)		if (ss_mask & (1 << ssid))
	cgroup_clear_dir(&ss->root->cgrp, 1 << ssid);		cgroup_clear_dir(&ss->root->cgrp, 1 << ssid);
	mutex_lock(&cgroup_mutex);		mutex_lock(&cgroup_mutex);

	@@ -1039,7 +1057,6 @@ static int rebind_subsystems(struct cgroup_root *dst_root,
	ss->bind(css);		ss->bind(css);
	}		}

	if (dst_root != &cgrp_dfl_root)
	kernfs_activate(dst_root->cgrp.kn);		kernfs_activate(dst_root->cgrp.kn);
	return 0;		return 0;
	}		}
	@@ -1190,16 +1207,6 @@ static int parse_cgroupfs_options(char data, struct cgroup_sb_opts opts)
	return -ENOENT;		return -ENOENT;
	}		}

	/*
	* If the 'all' option was specified select all the subsystems,
	* otherwise if 'none', 'name=' and a subsystem name options
	* were not specified, let's default to 'all'
	*/
	if (all_ss \|\| (!one_ss && !opts->none && !opts->name))
	for_each_subsys(ss, i)
	if (!ss->disabled)
	set_bit(i, &opts->subsys_mask);

	/* Consistency checks */		/* Consistency checks */

	if (opts->flags & CGRP_ROOT_SANE_BEHAVIOR) {		if (opts->flags & CGRP_ROOT_SANE_BEHAVIOR) {
	@@ -1211,6 +1218,23 @@ static int parse_cgroupfs_options(char data, struct cgroup_sb_opts opts)
	pr_err("cgroup: sane_behavior: noprefix, xattr, clone_children, release_agent and name are not allowed\n");		pr_err("cgroup: sane_behavior: noprefix, xattr, clone_children, release_agent and name are not allowed\n");
	return -EINVAL;		return -EINVAL;
	}		}
			} else {
			/*
			* If the 'all' option was specified select all the
			* subsystems, otherwise if 'none', 'name=' and a subsystem
			* name options were not specified, let's default to 'all'
			*/
			if (all_ss \|\| (!one_ss && !opts->none && !opts->name))
			for_each_subsys(ss, i)
			if (!ss->disabled)
			set_bit(i, &opts->subsys_mask);

			/*
			* We either have to specify by name or by subsystems. (So
			* all empty hierarchies must have a name).
			*/
			if (!opts->subsys_mask && !opts->name)
			return -EINVAL;
	}		}

	/*		/*
	@@ -1226,13 +1250,6 @@ static int parse_cgroupfs_options(char data, struct cgroup_sb_opts opts)
	if (opts->subsys_mask && opts->none)		if (opts->subsys_mask && opts->none)
	return -EINVAL;		return -EINVAL;

	/*
	* We either have to specify by name or by subsystems. (So all
	* empty hierarchies must have a name).
	*/
	if (!opts->subsys_mask && !opts->name)
	return -EINVAL;

	return 0;		return 0;
	}		}

	@@ -1487,6 +1504,14 @@ retry:
	goto out_unlock;		goto out_unlock;

	/* look for a matching existing root */		/* look for a matching existing root */
			if (!opts.subsys_mask && !opts.none && !opts.name) {
			cgrp_dfl_root_visible = true;
			root = &cgrp_dfl_root;
			cgroup_get(&root->cgrp);
			ret = 0;
			goto out_unlock;
			}

	for_each_root(root) {		for_each_root(root) {
	bool name_match = false;		bool name_match = false;

	@@ -3622,6 +3647,13 @@ static long cgroup_create(struct cgroup parent, const char name,
	struct cgroup_subsys *ss;		struct cgroup_subsys *ss;
	struct kernfs_node *kn;		struct kernfs_node *kn;

			/*
			* XXX: The default hierarchy isn't fully implemented yet. Block
			* !root cgroup creation on it for now.
			*/
			if (root == &cgrp_dfl_root)
			return -EINVAL;

	/* allocate the cgroup and its ID, 0 is reserved for the root */		/* allocate the cgroup and its ID, 0 is reserved for the root */
	cgrp = kzalloc(sizeof(*cgrp), GFP_KERNEL);		cgrp = kzalloc(sizeof(*cgrp), GFP_KERNEL);
	if (!cgrp)		if (!cgrp)
	@@ -4061,7 +4093,8 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss)
	*/		*/
	int __init cgroup_init_early(void)		int __init cgroup_init_early(void)
	{		{
	static struct cgroup_sb_opts __initdata opts = { };		static struct cgroup_sb_opts __initdata opts =
			{ .flags = CGRP_ROOT_SANE_BEHAVIOR };
	struct cgroup_subsys *ss;		struct cgroup_subsys *ss;
	int i;		int i;

	@@ -4198,7 +4231,7 @@ int proc_cgroup_show(struct seq_file m, void v)
	struct cgroup *cgrp;		struct cgroup *cgrp;
	int ssid, count = 0;		int ssid, count = 0;

	if (root == &cgrp_dfl_root)		if (root == &cgrp_dfl_root && !cgrp_dfl_root_visible)
	continue;		continue;

	seq_printf(m, "%d:", root->hierarchy_id);		seq_printf(m, "%d:", root->hierarchy_id);
	@@ -4631,15 +4664,10 @@ static int current_css_set_cg_links_read(struct seq_file seq, void v)
	cset = rcu_dereference(current->cgroups);		cset = rcu_dereference(current->cgroups);
	list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {		list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
	struct cgroup *c = link->cgrp;		struct cgroup *c = link->cgrp;
	const char *name = "?";

	if (c != &cgrp_dfl_root.cgrp) {
	cgroup_name(c, name_buf, NAME_MAX + 1);		cgroup_name(c, name_buf, NAME_MAX + 1);
	name = name_buf;
	}

	seq_printf(seq, "Root %d group %s\n",		seq_printf(seq, "Root %d group %s\n",
	c->root->hierarchy_id, name);		c->root->hierarchy_id, name_buf);
	}		}
	rcu_read_unlock();		rcu_read_unlock();
	up_read(&css_set_rwsem);		up_read(&css_set_rwsem);