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Commit bee55099 authored by Tejun Heo's avatar Tejun Heo
Browse files

cgroup: update error handling in cgroup_populate_dir() 



cgroup_populate_dir() didn't use to check whether the actual file
creations were successful and could return success with only subset of
the requested files created, which is nasty.

This patch udpates cgroup_populate_dir() so that it either succeeds
with all files or fails with no file.

v2: The original patch also converted for_each_root_subsys() usages to
    for_each_subsys() without explaining why.  That part has been
    moved to a separate patch.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarLi Zefan <lizefan@huawei.com>
parent 628f7cd4

kernel/cgroup.c

+11 −2
Original line number Diff line number Diff line
@@ -4171,10 +4171,13 @@ static struct cftype cgroup_base_files[] = { 
 * cgroup_populate_dir - create subsys files in a cgroup directory

 * @cgrp: target cgroup

 * @subsys_mask: mask of the subsystem ids whose files should be added

 *

 * On failure, no file is added.

 */

static int cgroup_populate_dir(struct cgroup *cgrp, unsigned long subsys_mask)

{

	struct cgroup_subsys *ss;

	int ret = 0;



	/* process cftsets of each subsystem */

	for_each_root_subsys(cgrp->root, ss) {
@@ -4182,8 +4185,11 @@ static int cgroup_populate_dir(struct cgroup *cgrp, unsigned long subsys_mask) 
		if (!test_bit(ss->subsys_id, &subsys_mask))

			continue;



		list_for_each_entry(set, &ss->cftsets, node)

			cgroup_addrm_files(cgrp, ss, set->cfts, true);

		list_for_each_entry(set, &ss->cftsets, node) {

			ret = cgroup_addrm_files(cgrp, ss, set->cfts, true);

			if (ret < 0)

				goto err;

		}

	}



	/* This cgroup is ready now */
@@ -4201,6 +4207,9 @@ static int cgroup_populate_dir(struct cgroup *cgrp, unsigned long subsys_mask) 
	}



	return 0;

err:

	cgroup_clear_dir(cgrp, subsys_mask);

	return ret;

}



static void css_dput_fn(struct work_struct *work)