diff options
| -rw-r--r-- | mm/bpf_memcontrol.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/mm/bpf_memcontrol.c b/mm/bpf_memcontrol.c index 82eb95de77b7..187919eb2fe2 100644 --- a/mm/bpf_memcontrol.c +++ b/mm/bpf_memcontrol.c @@ -11,6 +11,25 @@ __bpf_kfunc_start_defs(); /** + * bpf_get_root_mem_cgroup - Returns a pointer to the root memory cgroup + * + * The function has KF_ACQUIRE semantics, even though the root memory + * cgroup is never destroyed after being created and doesn't require + * reference counting. And it's perfectly safe to pass it to + * bpf_put_mem_cgroup() + * + * Return: A pointer to the root memory cgroup. + */ +__bpf_kfunc struct mem_cgroup *bpf_get_root_mem_cgroup(void) +{ + if (mem_cgroup_disabled()) + return NULL; + + /* css_get() is not needed */ + return root_mem_cgroup; +} + +/** * bpf_get_mem_cgroup - Get a reference to a memory cgroup * @css: pointer to the css structure * @@ -64,6 +83,7 @@ __bpf_kfunc void bpf_put_mem_cgroup(struct mem_cgroup *memcg) __bpf_kfunc_end_defs(); BTF_KFUNCS_START(bpf_memcontrol_kfuncs) +BTF_ID_FLAGS(func, bpf_get_root_mem_cgroup, KF_ACQUIRE | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_get_mem_cgroup, KF_ACQUIRE | KF_RET_NULL | KF_RCU) BTF_ID_FLAGS(func, bpf_put_mem_cgroup, KF_RELEASE) |