bpf: Eliminate rlimit-based memory accounting for stackmap maps

Do not use rlimit-based memory accounting for stackmap maps.
It has been replaced with the memcg-based memory accounting.
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20201201215900.3569844-30-guro@fb.com

kernel/bpf/stackmap.c

@@ -90,7 +90,6 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
 {
 	u32 value_size = attr->value_size;
 	struct bpf_stack_map *smap;
-	struct bpf_map_memory mem;
 	u64 cost, n_buckets;
 	int err;
 
@@ -119,15 +118,9 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
 
 	cost = n_buckets * sizeof(struct stack_map_bucket *) + sizeof(*smap);
 	cost += n_buckets * (value_size + sizeof(struct stack_map_bucket));
-	err = bpf_map_charge_init(&mem, cost);
-	if (err)
-		return ERR_PTR(err);
-
 	smap = bpf_map_area_alloc(cost, bpf_map_attr_numa_node(attr));
-	if (!smap) {
-		bpf_map_charge_finish(&mem);
+	if (!smap)
 		return ERR_PTR(-ENOMEM);
-	}
 
 	bpf_map_init_from_attr(&smap->map, attr);
 	smap->map.value_size = value_size;
@@ -135,20 +128,17 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
 
 	err = get_callchain_buffers(sysctl_perf_event_max_stack);
 	if (err)
-		goto free_charge;
+		goto free_smap;
 
 	err = prealloc_elems_and_freelist(smap);
 	if (err)
 		goto put_buffers;
 
-	bpf_map_charge_move(&smap->map.memory, &mem);
-
 	return &smap->map;
 
 put_buffers:
 	put_callchain_buffers();
-free_charge:
-	bpf_map_charge_finish(&mem);
+free_smap:
 	bpf_map_area_free(smap);
 	return ERR_PTR(err);
 }