Commit da70862e authored by Michal Koutný's avatar Michal Koutný Committed by Tejun Heo
Browse files

cgroup: cgroup.{procs,threads} factor out common parts 



The functions cgroup_threads_write and cgroup_procs_write are almost
identical. In order to reduce duplication, factor out the common code in
similar fashion we already do for other threadgroup/task functions. No
functional changes are intended.

Suggested-by: default avatarHao Lee <haolee.swjtu@gmail.com>
Signed-off-by: default avatarMichal Koutný <mkoutny@suse.com>
Reviewed-by: default avatarDaniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent b5e56576

kernel/cgroup/cgroup.c

+14 −41
Original line number Diff line number Diff line
@@ -4726,8 +4726,8 @@ static int cgroup_attach_permissions(struct cgroup *src_cgrp, 
	return ret;

}



static ssize_t cgroup_procs_write(struct kernfs_open_file *of,

				  char *buf, size_t nbytes, loff_t off)

static ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf,

				    bool threadgroup)

{

	struct cgroup *src_cgrp, *dst_cgrp;

	struct task_struct *task;
@@ -4738,7 +4738,7 @@ static ssize_t cgroup_procs_write(struct kernfs_open_file *of, 
	if (!dst_cgrp)

		return -ENODEV;



	task = cgroup_procs_write_start(buf, true, &locked);

	task = cgroup_procs_write_start(buf, threadgroup, &locked);

	ret = PTR_ERR_OR_ZERO(task);

	if (ret)

		goto out_unlock;
@@ -4748,19 +4748,26 @@ static ssize_t cgroup_procs_write(struct kernfs_open_file *of, 
	src_cgrp = task_cgroup_from_root(task, &cgrp_dfl_root);

	spin_unlock_irq(&css_set_lock);



	/* process and thread migrations follow same delegation rule */

	ret = cgroup_attach_permissions(src_cgrp, dst_cgrp,

					of->file->f_path.dentry->d_sb, true);

					of->file->f_path.dentry->d_sb, threadgroup);

	if (ret)

		goto out_finish;



	ret = cgroup_attach_task(dst_cgrp, task, true);

	ret = cgroup_attach_task(dst_cgrp, task, threadgroup);



out_finish:

	cgroup_procs_write_finish(task, locked);

out_unlock:

	cgroup_kn_unlock(of->kn);



	return ret ?: nbytes;

	return ret;

}



static ssize_t cgroup_procs_write(struct kernfs_open_file *of,

				  char *buf, size_t nbytes, loff_t off)

{

	return __cgroup_procs_write(of, buf, true) ?: nbytes;

}



static void *cgroup_threads_start(struct seq_file *s, loff_t *pos)
@@ -4771,41 +4778,7 @@ static void *cgroup_threads_start(struct seq_file *s, loff_t *pos) 
static ssize_t cgroup_threads_write(struct kernfs_open_file *of,

				    char *buf, size_t nbytes, loff_t off)

{

	struct cgroup *src_cgrp, *dst_cgrp;

	struct task_struct *task;

	ssize_t ret;

	bool locked;



	buf = strstrip(buf);



	dst_cgrp = cgroup_kn_lock_live(of->kn, false);

	if (!dst_cgrp)

		return -ENODEV;



	task = cgroup_procs_write_start(buf, false, &locked);

	ret = PTR_ERR_OR_ZERO(task);

	if (ret)

		goto out_unlock;



	/* find the source cgroup */

	spin_lock_irq(&css_set_lock);

	src_cgrp = task_cgroup_from_root(task, &cgrp_dfl_root);

	spin_unlock_irq(&css_set_lock);



	/* thread migrations follow the cgroup.procs delegation rule */

	ret = cgroup_attach_permissions(src_cgrp, dst_cgrp,

					of->file->f_path.dentry->d_sb, false);

	if (ret)

		goto out_finish;



	ret = cgroup_attach_task(dst_cgrp, task, false);



out_finish:

	cgroup_procs_write_finish(task, locked);

out_unlock:

	cgroup_kn_unlock(of->kn);



	return ret ?: nbytes;

	return __cgroup_procs_write(of, buf, false) ?: nbytes;

}



/* cgroup core interface files for the default hierarchy */