1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2019 Facebook
3 #include <linux/bpf.h>
4 #include <linux/version.h>
5 #include <bpf/bpf_helpers.h>
6 
7 #define VAR_NUM 16
8 
9 struct hmap_elem {
10 	struct bpf_spin_lock lock;
11 	int var[VAR_NUM];
12 };
13 
14 struct {
15 	__uint(type, BPF_MAP_TYPE_HASH);
16 	__uint(max_entries, 1);
17 	__type(key, __u32);
18 	__type(value, struct hmap_elem);
19 } hash_map SEC(".maps");
20 
21 struct array_elem {
22 	struct bpf_spin_lock lock;
23 	int var[VAR_NUM];
24 };
25 
26 struct {
27 	__uint(type, BPF_MAP_TYPE_ARRAY);
28 	__uint(max_entries, 1);
29 	__type(key, int);
30 	__type(value, struct array_elem);
31 } array_map SEC(".maps");
32 
33 SEC("cgroup/skb")
34 int bpf_map_lock_test(struct __sk_buff *skb)
35 {
36 	struct hmap_elem zero = {}, *val;
37 	int rnd = bpf_get_prandom_u32();
38 	int key = 0, err = 1, i;
39 	struct array_elem *q;
40 
41 	val = bpf_map_lookup_elem(&hash_map, &key);
42 	if (!val)
43 		goto err;
44 	/* spin_lock in hash map */
45 	bpf_spin_lock(&val->lock);
46 	for (i = 0; i < VAR_NUM; i++)
47 		val->var[i] = rnd;
48 	bpf_spin_unlock(&val->lock);
49 
50 	/* spin_lock in array */
51 	q = bpf_map_lookup_elem(&array_map, &key);
52 	if (!q)
53 		goto err;
54 	bpf_spin_lock(&q->lock);
55 	for (i = 0; i < VAR_NUM; i++)
56 		q->var[i] = rnd;
57 	bpf_spin_unlock(&q->lock);
58 	err = 0;
59 err:
60 	return err;
61 }
62 char _license[] SEC("license") = "GPL";
63