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authorLi Zefan <lizf@cn.fujitsu.com>2010-05-07 06:57:00 (GMT)
committerJens Axboe <jens.axboe@oracle.com>2010-05-07 06:57:00 (GMT)
commit0341509fdfc9519f7de6aabc5dd23217cef72b73 (patch)
tree84415f35129013b9d8fb3f5f0ef266437a02f09c /block/blk-cgroup.c
parentdcf097b247affd8b88ad410a92298590c5600f44 (diff)
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 <lizf@cn.fujitsu.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-cgroup.c')
-rw-r--r--block/blk-cgroup.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 5fe03de..2cc682b 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);

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