aboutsummaryrefslogtreecommitdiffstats
path: root/block
diff options
context:
space:
mode:
authorLi Zefan <lizf@cn.fujitsu.com>2010-05-07 02:57:00 -0400
committerJens Axboe <jens.axboe@oracle.com>2010-05-07 02:57:00 -0400
commit0341509fdfc9519f7de6aabc5dd23217cef72b73 (patch)
tree84415f35129013b9d8fb3f5f0ef266437a02f09c /block
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')
-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 5fe03def34b2..2cc682b860ea 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -286,16 +286,16 @@ done:
286static struct cgroup_subsys_state * 286static struct cgroup_subsys_state *
287blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup) 287blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup)
288{ 288{
289 struct blkio_cgroup *blkcg, *parent_blkcg; 289 struct blkio_cgroup *blkcg;
290 struct cgroup *parent = cgroup->parent;
290 291
291 if (!cgroup->parent) { 292 if (!parent) {
292 blkcg = &blkio_root_cgroup; 293 blkcg = &blkio_root_cgroup;
293 goto done; 294 goto done;
294 } 295 }
295 296
296 /* Currently we do not support hierarchy deeper than two level (0,1) */ 297 /* Currently we do not support hierarchy deeper than two level (0,1) */
297 parent_blkcg = cgroup_to_blkio_cgroup(cgroup->parent); 298 if (parent != cgroup->top_cgroup)
298 if (css_depth(&parent_blkcg->css) > 0)
299 return ERR_PTR(-EINVAL); 299 return ERR_PTR(-EINVAL);
300 300
301 blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL); 301 blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);