| // SPDX-License-Identifier: GPL-2.0 |
| // Copyright (c) 2019 Facebook |
| #include <linux/bpf.h> |
| #include <linux/version.h> |
| #include "bpf_helpers.h" |
| |
| #define VAR_NUM 16 |
| |
| struct hmap_elem { |
| struct bpf_spin_lock lock; |
| int var[VAR_NUM]; |
| }; |
| |
| struct bpf_map_def SEC("maps") hash_map = { |
| .type = BPF_MAP_TYPE_HASH, |
| .key_size = sizeof(int), |
| .value_size = sizeof(struct hmap_elem), |
| .max_entries = 1, |
| }; |
| |
| BPF_ANNOTATE_KV_PAIR(hash_map, int, struct hmap_elem); |
| |
| struct array_elem { |
| struct bpf_spin_lock lock; |
| int var[VAR_NUM]; |
| }; |
| |
| struct bpf_map_def SEC("maps") array_map = { |
| .type = BPF_MAP_TYPE_ARRAY, |
| .key_size = sizeof(int), |
| .value_size = sizeof(struct array_elem), |
| .max_entries = 1, |
| }; |
| |
| BPF_ANNOTATE_KV_PAIR(array_map, int, struct array_elem); |
| |
| SEC("map_lock_demo") |
| int bpf_map_lock_test(struct __sk_buff *skb) |
| { |
| struct hmap_elem zero = {}, *val; |
| int rnd = bpf_get_prandom_u32(); |
| int key = 0, err = 1, i; |
| struct array_elem *q; |
| |
| val = bpf_map_lookup_elem(&hash_map, &key); |
| if (!val) |
| goto err; |
| /* spin_lock in hash map */ |
| bpf_spin_lock(&val->lock); |
| for (i = 0; i < VAR_NUM; i++) |
| val->var[i] = rnd; |
| bpf_spin_unlock(&val->lock); |
| |
| /* spin_lock in array */ |
| q = bpf_map_lookup_elem(&array_map, &key); |
| if (!q) |
| goto err; |
| bpf_spin_lock(&q->lock); |
| for (i = 0; i < VAR_NUM; i++) |
| q->var[i] = rnd; |
| bpf_spin_unlock(&q->lock); |
| err = 0; |
| err: |
| return err; |
| } |
| char _license[] SEC("license") = "GPL"; |