Commit a6d1ce59 authored by Yosry Ahmed's avatar Yosry Ahmed Committed by Tejun Heo
Browse files

cgroup: add cgroup_v1v2_get_from_[fd/file]() 



Add cgroup_v1v2_get_from_fd() and cgroup_v1v2_get_from_file() that
support both cgroup1 and cgroup2.

Signed-off-by: default avatarYosry Ahmed <yosryahmed@google.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 03db7716

include/linux/cgroup.h

+1 −0
Original line number Diff line number Diff line
@@ -106,6 +106,7 @@ struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry, 


struct cgroup *cgroup_get_from_path(const char *path);

struct cgroup *cgroup_get_from_fd(int fd);

struct cgroup *cgroup_v1v2_get_from_fd(int fd);



int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);

int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);

kernel/cgroup/cgroup.c

+44 −6
Original line number Diff line number Diff line
@@ -6224,16 +6224,36 @@ void cgroup_fork(struct task_struct *child) 
	INIT_LIST_HEAD(&child->cg_list);

}



static struct cgroup *cgroup_get_from_file(struct file *f)

/**

 * cgroup_v1v2_get_from_file - get a cgroup pointer from a file pointer

 * @f: file corresponding to cgroup_dir

 *

 * Find the cgroup from a file pointer associated with a cgroup directory.

 * Returns a pointer to the cgroup on success. ERR_PTR is returned if the

 * cgroup cannot be found.

 */

static struct cgroup *cgroup_v1v2_get_from_file(struct file *f)

{

	struct cgroup_subsys_state *css;

	struct cgroup *cgrp;



	css = css_tryget_online_from_dir(f->f_path.dentry, NULL);

	if (IS_ERR(css))

		return ERR_CAST(css);



	cgrp = css->cgroup;

	return css->cgroup;

}



/**

 * cgroup_get_from_file - same as cgroup_v1v2_get_from_file, but only supports

 * cgroup2.

 */

static struct cgroup *cgroup_get_from_file(struct file *f)

{

	struct cgroup *cgrp = cgroup_v1v2_get_from_file(f);



	if (IS_ERR(cgrp))

		return ERR_CAST(cgrp);



	if (!cgroup_on_dfl(cgrp)) {

		cgroup_put(cgrp);

		return ERR_PTR(-EBADF);
@@ -6734,14 +6754,14 @@ EXPORT_SYMBOL_GPL(cgroup_get_from_path); 


/**

 * cgroup_get_from_fd - get a cgroup pointer from a fd

 * @fd: fd obtained by open(cgroup2_dir)

 * @fd: fd obtained by open(cgroup_dir)

 *

 * Find the cgroup from a fd which should be obtained

 * by opening a cgroup directory.  Returns a pointer to the

 * cgroup on success. ERR_PTR is returned if the cgroup

 * cannot be found.

 */

struct cgroup *cgroup_get_from_fd(int fd)

struct cgroup *cgroup_v1v2_get_from_fd(int fd)

{

	struct cgroup *cgrp;

	struct file *f;
@@ -6750,10 +6770,28 @@ struct cgroup *cgroup_get_from_fd(int fd) 
	if (!f)

		return ERR_PTR(-EBADF);



	cgrp = cgroup_get_from_file(f);

	cgrp = cgroup_v1v2_get_from_file(f);

	fput(f);

	return cgrp;

}



/**

 * cgroup_get_from_fd - same as cgroup_v1v2_get_from_fd, but only supports

 * cgroup2.

 */

struct cgroup *cgroup_get_from_fd(int fd)

{

	struct cgroup *cgrp = cgroup_v1v2_get_from_fd(fd);



	if (IS_ERR(cgrp))

		return ERR_CAST(cgrp);



	if (!cgroup_on_dfl(cgrp)) {

		cgroup_put(cgrp);

		return ERR_PTR(-EBADF);

	}

	return cgrp;

}

EXPORT_SYMBOL_GPL(cgroup_get_from_fd);



static u64 power_of_ten(int power)