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| author | Tejun Heo <tj@kernel.org> | 2014-04-23 11:13:15 -0400 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2014-04-23 11:13:15 -0400 |
| commit | 3b281afbc3a06cd69c54e6db1a04a8e73997723f (patch) | |
| tree | fe6fd8897b317f391ec7d2f55f7cb6f6370d8a7f /kernel/cgroup.c | |
| parent | 2d8f243a5e6efa57fb7c46fe83fafa45b33d0ec2 (diff) | |
| download | lwn-3b281afbc3a06cd69c54e6db1a04a8e73997723f.tar.gz lwn-3b281afbc3a06cd69c54e6db1a04a8e73997723f.zip | |
cgroup: make css_next_child() skip missing csses
css_next_child() walks the children of the specified css. It does
this by finding the next cgroup and then returning the requested css.
On the default unified hierarchy, a cgroup may not have a css
associated with it even if the hierarchy has the subsystem enabled.
This patch updates css_next_child() so that it skips children without
the requested css associated.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 37d966289978..0edc186cd545 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2708,10 +2708,19 @@ css_next_child(struct cgroup_subsys_state *pos_css, break; } - if (&next->sibling == &cgrp->children) - return NULL; + /* + * @next, if not pointing to the head, can be dereferenced and is + * the next sibling; however, it might have @ss disabled. If so, + * fast-forward to the next enabled one. + */ + while (&next->sibling != &cgrp->children) { + struct cgroup_subsys_state *next_css = cgroup_css(next, parent_css->ss); - return cgroup_css(next, parent_css->ss); + if (next_css) + return next_css; + next = list_entry_rcu(next->sibling.next, struct cgroup, sibling); + } + return NULL; } /** |