The current implementation of cgroup_get_from_id() only searches the
default hierarchy for the given id. Make it compatible with cgroup v1 by
looking through all the roots instead.
cgrp_dfl_root should be the first element in the list so there shouldn't
be a performance impact for cgroup v2 users (in the case of a valid id).
Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
---
kernel/cgroup/cgroup.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index af703cfcb9d2..12700cd21973 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -5970,10 +5970,16 @@ void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen)
*/
struct cgroup *cgroup_get_from_id(u64 id)
{
- struct kernfs_node *kn;
+ struct kernfs_node *kn = NULL;
struct cgroup *cgrp = NULL;
+ struct cgroup_root *root;
+
+ for_each_root(root) {
+ kn = kernfs_find_and_get_node_by_id(root->kf_root, id);
+ if (kn)
+ break;
+ }
- kn = kernfs_find_and_get_node_by_id(cgrp_dfl_root.kf_root, id);
if (!kn)
goto out;
--
2.36.0.512.ge40c2bad7a-goog
