tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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_helpers.h"
6
7#define VAR_NUM 16
8
9struct hmap_elem {
10 struct bpf_spin_lock lock;
11 int var[VAR_NUM];
12};
13
14struct bpf_map_def SEC("maps") hash_map = {
15 .type = BPF_MAP_TYPE_HASH,
16 .key_size = sizeof(int),
17 .value_size = sizeof(struct hmap_elem),
18 .max_entries = 1,
19};
20
21BPF_ANNOTATE_KV_PAIR(hash_map, int, struct hmap_elem);
22
23struct array_elem {
24 struct bpf_spin_lock lock;
25 int var[VAR_NUM];
26};
27
28struct bpf_map_def SEC("maps") array_map = {
29 .type = BPF_MAP_TYPE_ARRAY,
30 .key_size = sizeof(int),
31 .value_size = sizeof(struct array_elem),
32 .max_entries = 1,
33};
34
35BPF_ANNOTATE_KV_PAIR(array_map, int, struct array_elem);
36
37SEC("map_lock_demo")
38int bpf_map_lock_test(struct __sk_buff *skb)
39{
40 struct hmap_elem zero = {}, *val;
41 int rnd = bpf_get_prandom_u32();
42 int key = 0, err = 1, i;
43 struct array_elem *q;
44
45 val = bpf_map_lookup_elem(&hash_map, &key);
46 if (!val)
47 goto err;
48 /* spin_lock in hash map */
49 bpf_spin_lock(&val->lock);
50 for (i = 0; i < VAR_NUM; i++)
51 val->var[i] = rnd;
52 bpf_spin_unlock(&val->lock);
53
54 /* spin_lock in array */
55 q = bpf_map_lookup_elem(&array_map, &key);
56 if (!q)
57 goto err;
58 bpf_spin_lock(&q->lock);
59 for (i = 0; i < VAR_NUM; i++)
60 q->var[i] = rnd;
61 bpf_spin_unlock(&q->lock);
62 err = 0;
63err:
64 return err;
65}
66char _license[] SEC("license") = "GPL";