cgroup: introduce cgroup_ino()
mm/memory-failure.c::hwpoison_filter_task() has been reaching into
cgroup to extract the associated ino to be used as a filtering
criterion. This is an implementation detail which shouldn't be
depended upon from outside cgroup proper and is about to change with
the scheduled kernfs conversion.
This patch introduces a proper interface to determine the associated
ino, cgroup_ino(), and updates hwpoison_filter_task() to use it
instead of reaching directly into cgroup.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 4f08a2d..9b5933c 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -145,14 +145,10 @@
return -EINVAL;
css = mem_cgroup_css(mem);
- /* root_mem_cgroup has NULL dentries */
- if (!css->cgroup->dentry)
- return -EINVAL;
-
- ino = css->cgroup->dentry->d_inode->i_ino;
+ ino = cgroup_ino(css->cgroup);
css_put(css);
- if (ino != hwpoison_filter_memcg)
+ if (!ino || ino != hwpoison_filter_memcg)
return -EINVAL;
return 0;