Messages in this thread Patch in this message | | | From | Tejun Heo <> | Subject | [PATCH 04/12] cgroup: make css_next_child() skip missing csses | Date | Mon, 14 Apr 2014 17:37:02 -0400 |
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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> --- kernel/cgroup.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 29e8698..f525578 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2712,10 +2712,19 @@ 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; } /** -- 1.9.0
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