diff options
| -rw-r--r-- | mm/bpf_memcontrol.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/mm/bpf_memcontrol.c b/mm/bpf_memcontrol.c index 716df49d7647..f95cd5d16f4c 100644 --- a/mm/bpf_memcontrol.c +++ b/mm/bpf_memcontrol.c @@ -13,12 +13,12 @@ __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. + * Return: A pointer to the root memory cgroup. Notably, the pointer to the + * returned struct mem_cgroup is trusted by default, so it's perfectably + * acceptable to also pass this pointer into other BPF kfuncs (e.g., + * bpf_mem_cgroup_usage()). Additionally, this BPF kfunc does not make use of + * KF_ACQUIRE semantics, so there's no requirement for the BPF program to call + * bpf_put_mem_cgroup() on the pointer returned by this BPF kfunc. */ __bpf_kfunc struct mem_cgroup *bpf_get_root_mem_cgroup(void) { @@ -162,7 +162,7 @@ __bpf_kfunc void bpf_mem_cgroup_flush_stats(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_root_mem_cgroup, 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) |