bpf: Eliminate rlimit-based memory accounting for hashtab maps

Do not use rlimit-based memory accounting for hashtab 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/20201201215900.3569844-24-guro@fb.com

kernel/bpf/hashtab.c

@@ -443,7 +443,6 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
 	bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
 	struct bpf_htab *htab;
 	int err, i;
-	u64 cost;
 
 	htab = kzalloc(sizeof(*htab), GFP_USER | __GFP_ACCOUNT);
 	if (!htab)
@@ -481,26 +480,12 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
 	    htab->n_buckets > U32_MAX / sizeof(struct bucket))
 		goto free_htab;
 
-	cost = (u64) htab->n_buckets * sizeof(struct bucket) +
-	       (u64) htab->elem_size * htab->map.max_entries;
-
-	if (percpu)
-		cost += (u64) round_up(htab->map.value_size, 8) *
-			num_possible_cpus() * htab->map.max_entries;
-	else
-	       cost += (u64) htab->elem_size * num_possible_cpus();
-
-	/* if map size is larger than memlock limit, reject it */
-	err = bpf_map_charge_init(&htab->map.memory, cost);
-	if (err)
-		goto free_htab;
-
 	err = -ENOMEM;
 	htab->buckets = bpf_map_area_alloc(htab->n_buckets *
 					   sizeof(struct bucket),
 					   htab->map.numa_node);
 	if (!htab->buckets)
-		goto free_charge;
+		goto free_htab;
 
 	for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++) {
 		htab->map_locked[i] = bpf_map_alloc_percpu(&htab->map,
@@ -541,8 +526,6 @@ free_map_locked:
 	for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
 		free_percpu(htab->map_locked[i]);
 	bpf_map_area_free(htab->buckets);
-free_charge:
-	bpf_map_charge_finish(&htab->map.memory);
 free_htab:
 	lockdep_unregister_key(&htab->lockdep_key);
 	kfree(htab);