From 0341509fdfc9519f7de6aabc5dd23217cef72b73 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Fri, 7 May 2010 08:57:00 +0200 Subject: blk-cgroup: Fix an RCU warning in blkiocg_create() with CONFIG_PROVE_RCU=y, a warning can be triggered: # mount -t cgroup -o blkio xxx /mnt # mkdir /mnt/subgroup ... kernel/cgroup.c:4442 invoked rcu_dereference_check() without protection! ... To fix this, we avoid caling css_depth() here, which is a bit simpler than the original code. Signed-off-by: Li Zefan Acked-by: Vivek Goyal Signed-off-by: Jens Axboe --- block/blk-cgroup.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'block') diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 5fe03def34b2..2cc682b860ea 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -286,16 +286,16 @@ done: static struct cgroup_subsys_state * blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup) { - struct blkio_cgroup *blkcg, *parent_blkcg; + struct blkio_cgroup *blkcg; + struct cgroup *parent = cgroup->parent; - if (!cgroup->parent) { + if (!parent) { blkcg = &blkio_root_cgroup; goto done; } /* Currently we do not support hierarchy deeper than two level (0,1) */ - parent_blkcg = cgroup_to_blkio_cgroup(cgroup->parent); - if (css_depth(&parent_blkcg->css) > 0) + if (parent != cgroup->top_cgroup) return ERR_PTR(-EINVAL); blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL); -- cgit v1.2.1