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-rw-r--r--kernel/bpf/helpers.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 420a4251cccc..e4e9db301db5 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -1938,6 +1938,25 @@ void bpf_cgroup_release(struct cgroup *cgrp)
cgroup_put(cgrp);
}
+
+/**
+ * bpf_cgroup_ancestor - Perform a lookup on an entry in a cgroup's ancestor
+ * array. A cgroup returned by this kfunc which is not subsequently stored in a
+ * map, must be released by calling bpf_cgroup_release().
+ * @cgrp: The cgroup for which we're performing a lookup.
+ * @level: The level of ancestor to look up.
+ */
+struct cgroup *bpf_cgroup_ancestor(struct cgroup *cgrp, int level)
+{
+ struct cgroup *ancestor;
+
+ if (level > cgrp->level || level < 0)
+ return NULL;
+
+ ancestor = cgrp->ancestors[level];
+ cgroup_get(ancestor);
+ return ancestor;
+}
#endif /* CONFIG_CGROUPS */
void *bpf_cast_to_kern_ctx(void *obj)
@@ -1970,6 +1989,7 @@ BTF_ID_FLAGS(func, bpf_task_release, KF_RELEASE)
BTF_ID_FLAGS(func, bpf_cgroup_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS)
BTF_ID_FLAGS(func, bpf_cgroup_kptr_get, KF_ACQUIRE | KF_KPTR_GET | KF_RET_NULL)
BTF_ID_FLAGS(func, bpf_cgroup_release, KF_RELEASE)
+BTF_ID_FLAGS(func, bpf_cgroup_ancestor, KF_ACQUIRE | KF_TRUSTED_ARGS | KF_RET_NULL)
#endif
BTF_SET8_END(generic_btf_ids)