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authorTejun Heo <tj@kernel.org>2015-11-05 00:12:24 -0500
committerTejun Heo <tj@kernel.org>2015-11-16 10:58:26 -0500
commit34c06254ff82a815fdccdfae7517a06c9b768cee (patch)
tree95b146ae8a28f04a91a84983a407b463460662cb /include/linux/cgroup-defs.h
parent8005c49d9aea74d382f474ce11afbbc7d7130bec (diff)
cgroup: fix cftype->file_offset handling
6f60eade2433 ("cgroup: generalize obtaining the handles of and notifying cgroup files") introduced cftype->file_offset so that the handles for per-css file instances can be recorded. These handles then can be used, for example, to generate file modified notifications. Unfortunately, it made the wrong assumption that files are created once for a given css and removed on its destruction. Due to the dependencies among subsystems, a css may be hidden from userland and then later shown again. This is implemented by removing and re-creating the affected files, so the associated kernfs_node for a given cgroup file may change over time. This incorrect assumption led to the corruption of css->files lists. Reimplement cftype->file_offset handling so that cgroup_file->kn is protected by a lock and updated as files are created and destroyed. This also makes keeping them on per-cgroup list unnecessary. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: James Sedgwick <jsedgwick@fb.com> Fixes: 6f60eade2433 ("cgroup: generalize obtaining the handles of and notifying cgroup files") Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Zefan Li <lizefan@huawei.com>
Diffstat (limited to 'include/linux/cgroup-defs.h')
-rw-r--r--include/linux/cgroup-defs.h4
1 files changed, 0 insertions, 4 deletions
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 60d44b26276d..869fd4a3d28e 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -90,7 +90,6 @@ enum {
*/
struct cgroup_file {
/* do not access any fields from outside cgroup core */
- struct list_head node; /* anchored at css->files */
struct kernfs_node *kn;
};
@@ -134,9 +133,6 @@ struct cgroup_subsys_state {
*/
u64 serial_nr;
- /* all cgroup_files associated with this css */
- struct list_head files;
-
/* percpu_ref killing and RCU release */
struct rcu_head rcu_head;
struct work_struct destroy_work;