Commit b4f5f93b authored by Lu Jialin's avatar Lu Jialin Committed by yanhaitao
Browse files

cgroup: factor out __cgroup_get_from_id() for cgroup v1 

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8LY4S



-------------------------------

Add __cgroup_get_from_id() function to help cgroupv1 get cgroup through
cgroup inode;

The patch also export cgroup_tryget_css(), which will be used later

Signed-off-by: default avatarLu Jialin <lujialin4@huawei.com>
Signed-off-by: default avatarchenridong <chenridong@huawei.com>
parent 6d225089

include/linux/cgroup-defs.h

+2 −0
Original line number Diff line number Diff line
@@ -778,6 +778,8 @@ static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) 
	percpu_up_read(&cgroup_threadgroup_rwsem);

}



struct cgroup_subsys_state *cgroup_tryget_css(struct cgroup *cgrp,

					      struct cgroup_subsys *ss);

#else	/* CONFIG_CGROUPS */



#define CGROUP_SUBSYS_COUNT 0

include/linux/cgroup.h

+1 −0
Original line number Diff line number Diff line
@@ -633,6 +633,7 @@ static inline void cgroup_kthread_ready(void) 
}



void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen);

struct cgroup *__cgroup_get_from_id(struct cgroup_root *root, u64 id);

struct cgroup *cgroup_get_from_id(u64 id);

#else /* !CONFIG_CGROUPS */

kernel/cgroup/cgroup.c

+24 −6
Original line number Diff line number Diff line
@@ -3652,7 +3652,6 @@ static int cgroup_stat_show(struct seq_file *seq, void *v) 
	return 0;

}



#ifdef CONFIG_CGROUP_SCHED

/**

 * cgroup_tryget_css - try to get a cgroup's css for the specified subsystem

 * @cgrp: the cgroup of interest
@@ -3661,7 +3660,7 @@ static int cgroup_stat_show(struct seq_file *seq, void *v) 
 * Find and get @cgrp's css associated with @ss.  If the css doesn't exist

 * or is offline, %NULL is returned.

 */

static struct cgroup_subsys_state *cgroup_tryget_css(struct cgroup *cgrp,

struct cgroup_subsys_state *cgroup_tryget_css(struct cgroup *cgrp,

						     struct cgroup_subsys *ss)

{

	struct cgroup_subsys_state *css;
@@ -3675,6 +3674,7 @@ static struct cgroup_subsys_state *cgroup_tryget_css(struct cgroup *cgrp, 
	return css;

}



#ifdef CONFIG_CGROUP_SCHED

static int cgroup_extra_stat_show(struct seq_file *seq, int ssid)

{

	struct cgroup *cgrp = seq_css(seq)->cgroup;
@@ -6203,17 +6203,18 @@ void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen) 
}



/*

 * cgroup_get_from_id : get the cgroup associated with cgroup id

 * __cgroup_get_from_id : get the cgroup associated with cgroup root and id

 * @root: hierarchy root

 * @id: cgroup id

 * On success return the cgrp or ERR_PTR on failure

 * Only cgroups within current task's cgroup NS are valid.

 */

struct cgroup *cgroup_get_from_id(u64 id)

struct cgroup *__cgroup_get_from_id(struct cgroup_root *root, u64 id)

{

	struct kernfs_node *kn;

	struct cgroup *cgrp, *root_cgrp;



	kn = kernfs_find_and_get_node_by_id(cgrp_dfl_root.kf_root, id);

	kn = kernfs_find_and_get_node_by_id(root->kf_root, id);

	if (!kn)

		return ERR_PTR(-ENOENT);
@@ -6234,7 +6235,13 @@ struct cgroup *cgroup_get_from_id(u64 id) 
	if (!cgrp)

		return ERR_PTR(-ENOENT);



	if (root == &cgrp_dfl_root)

		root_cgrp = current_cgns_cgroup_dfl();

	else {

		spin_lock_irq(&css_set_lock);

		root_cgrp = current_cgns_cgroup_from_root(root);

		spin_unlock_irq(&css_set_lock);

	}

	if (!cgroup_is_descendant(cgrp, root_cgrp)) {

		cgroup_put(cgrp);

		return ERR_PTR(-ENOENT);
@@ -6242,6 +6249,17 @@ struct cgroup *cgroup_get_from_id(u64 id) 


	return cgrp;

}



/*

 * cgroup_get_from_id : get the cgroup at dfl hierarchy associated with cgroup id

 * @id: cgroup id

 * On success return the cgrp or ERR_PTR on failure

 * Only cgroups within current task's cgroup NS are valid.

 */

struct cgroup *cgroup_get_from_id(u64 id)

{

	return __cgroup_get_from_id(&cgrp_dfl_root, id);

}

EXPORT_SYMBOL_GPL(cgroup_get_from_id);



/*