Commit e2691f6b authored by Tejun Heo's avatar Tejun Heo Committed by Greg Kroah-Hartman
Browse files

cgroup: Implement cgroup_file_show() 



Add cgroup_file_show() which allows toggling visibility of a cgroup file
using the new kernfs_show(). This will be used to hide psi interface files
on cgroups where it's disabled.

Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: default avatarChengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: default avatarChengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220828050440.734579-10-tj@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 783bd07d

include/linux/cgroup.h

+1 −0
Original line number Diff line number Diff line
@@ -114,6 +114,7 @@ int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); 
int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);

int cgroup_rm_cftypes(struct cftype *cfts);

void cgroup_file_notify(struct cgroup_file *cfile);

void cgroup_file_show(struct cgroup_file *cfile, bool show);



int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);

int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry);

kernel/cgroup/cgroup.c

+20 −0
Original line number Diff line number Diff line
@@ -4339,6 +4339,26 @@ void cgroup_file_notify(struct cgroup_file *cfile) 
	spin_unlock_irqrestore(&cgroup_file_kn_lock, flags);

}



/**

 * cgroup_file_show - show or hide a hidden cgroup file

 * @cfile: target cgroup_file obtained by setting cftype->file_offset

 * @show: whether to show or hide

 */

void cgroup_file_show(struct cgroup_file *cfile, bool show)

{

	struct kernfs_node *kn;



	spin_lock_irq(&cgroup_file_kn_lock);

	kn = cfile->kn;

	kernfs_get(kn);

	spin_unlock_irq(&cgroup_file_kn_lock);



	if (kn)

		kernfs_show(kn, show);



	kernfs_put(kn);

}



/**

 * css_next_child - find the next child of a given css

 * @pos: the current position (%NULL to initiate traversal)