cgroup: move number_of_cgroups test out of rebind_subsystems() into cgroup_remount() (f172e67c) · Commits · 戴 / test

rebind_subsystems() currently fails if the hierarchy has any !root cgroups; however, on the planned unified hierarchy, rebind_subsystems() will be used while populated. Move the test to cgroup_remount(), which is the only place the test is necessary anyway. As it's impossible for the other two callers of rebind_subsystems() to have populated hierarchy, this doesn't make any behavior changes. Signed-off-by:

Tejun Heo <tj@kernel.org> Acked-by:

Li Zefan <lizefan@huawei.com>

kernel/cgroup.c

+6 −7

Original line number	Diff line number	Diff line
		@@ -1021,13 +1021,6 @@ static int rebind_subsystems(struct cgroupfs_root *root,
		}
		}

		/* Currently we don't handle adding/removing subsystems when
		* any child cgroups exist. This is theoretically supportable
		* but involves complex error handling, so it's being left until
		* later */
		if (root->number_of_cgroups > 1)
		return -EBUSY;

		ret = cgroup_populate_dir(cgrp, added_mask);
		if (ret)
		return ret;
		@@ -1373,6 +1366,12 @@ static int cgroup_remount(struct super_block sb, int flags, char *data)
		goto out_unlock;
		}

		/* remounting is not allowed for populated hierarchies */
		if (root->number_of_cgroups > 1) {
		ret = -EBUSY;
		goto out_unlock;
		}

		ret = rebind_subsystems(root, added_mask, removed_mask);
		if (ret)
		goto out_unlock;

Admin message