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Commit 33a68ac1 authored by Li Zefan's avatar Li Zefan Committed by Linus Torvalds
Browse files

cgroups: add inactive subsystems to rootnode.subsys_list 



Though for an inactive hierarchy, we have subsys->root == &rootnode, but
rootnode's subsys_list is always empty.

This conflicts with the code in find_css_set():

	for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
		...
		if (ss->root->subsys_list.next == &ss->sibling) {
			...
		}
	}
	if (list_empty(&rootnode.subsys_list)) {
		...
	}

The above code assumes rootnode.subsys_list links all inactive
hierarchies.

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e5f6a860

kernel/cgroup.c

+3 −2
Original line number Diff line number Diff line
@@ -712,7 +712,7 @@ static int rebind_subsystems(struct cgroupfs_root *root, 
			BUG_ON(dummytop->subsys[i]->cgroup != dummytop);

			cgrp->subsys[i] = dummytop->subsys[i];

			cgrp->subsys[i]->cgroup = cgrp;

			list_add(&ss->sibling, &root->subsys_list);

			list_move(&ss->sibling, &root->subsys_list);

			ss->root = root;

			if (ss->bind)

				ss->bind(ss, cgrp);
@@ -726,7 +726,7 @@ static int rebind_subsystems(struct cgroupfs_root *root, 
			dummytop->subsys[i]->cgroup = dummytop;

			cgrp->subsys[i] = NULL;

			subsys[i]->root = &rootnode;

			list_del(&ss->sibling);

			list_move(&ss->sibling, &rootnode.subsys_list);

		} else if (bit & final_bits) {

			/* Subsystem state should already exist */

			BUG_ON(!cgrp->subsys[i]);
@@ -2521,6 +2521,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss) 
	printk(KERN_INFO "Initializing cgroup subsys %s\n", ss->name);



	/* Create the top cgroup state for this subsystem */

	list_add(&ss->sibling, &rootnode.subsys_list);

	ss->root = &rootnode;

	css = ss->create(ss, dummytop);

	/* We don't handle early failures gracefully */