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Commit 1cb650b9 authored by Li Zefan's avatar Li Zefan Committed by Tejun Heo
Browse files

cgroup: change cgroup_from_id() to css_from_id() 



Now we want cgroup core to always provide the css to use to the
subsystems, so change this API to css_from_id().

Uninline css_from_id(), because it's getting bigger and cgroup_css()
has been unexported.

While at it, remove the #ifdef, and shuffle the order of the args.

Signed-off-by: default avatarLi Zefan <lizefan@huawei.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 930913a3

include/linux/cgroup.h

+2 −18
Original line number Diff line number Diff line
@@ -741,27 +741,11 @@ static inline struct cgroup *task_cgroup(struct task_struct *task, 
	return task_css(task, subsys_id)->cgroup;

}



/**

 * cgroup_from_id - lookup cgroup by id

 * @ss: cgroup subsys to be looked into

 * @id: the cgroup id

 *

 * Returns the cgroup if there's valid one with @id, otherwise returns NULL.

 * Should be called under rcu_read_lock().

 */

static inline struct cgroup *cgroup_from_id(struct cgroup_subsys *ss, int id)

{

#ifdef CONFIG_PROVE_RCU

	rcu_lockdep_assert(rcu_read_lock_held() ||

			   lockdep_is_held(&cgroup_mutex),

			   "cgroup_from_id() needs proper protection");

#endif

	return idr_find(&ss->root->cgroup_idr, id);

}



struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos,

					   struct cgroup_subsys_state *parent);



struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss);



/**

 * css_for_each_child - iterate through children of a css

 * @pos: the css * to use as the loop cursor

kernel/cgroup.c

+22 −0
Original line number Diff line number Diff line
@@ -5717,6 +5717,28 @@ struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id) 
	return css ? css : ERR_PTR(-ENOENT);

}



/**

 * css_from_id - lookup css by id

 * @id: the cgroup id

 * @ss: cgroup subsys to be looked into

 *

 * Returns the css if there's valid one with @id, otherwise returns NULL.

 * Should be called under rcu_read_lock().

 */

struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss)

{

	struct cgroup *cgrp;



	rcu_lockdep_assert(rcu_read_lock_held() ||

			   lockdep_is_held(&cgroup_mutex),

			   "css_from_id() needs proper protection");



	cgrp = idr_find(&ss->root->cgroup_idr, id);

	if (cgrp)

		return cgroup_css(cgrp, ss->subsys_id);

	return NULL;

}



#ifdef CONFIG_CGROUP_DEBUG

static struct cgroup_subsys_state *

debug_css_alloc(struct cgroup_subsys_state *parent_css)