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 #include "bpf_misc.h"
7
8 struct hmap_elem {
9 volatile int cnt;
10 struct bpf_spin_lock lock;
11 int test_padding;
12 };
13
14 struct {
15 __uint(type, BPF_MAP_TYPE_HASH);
16 __uint(max_entries, 1);
17 __type(key, int);
18 __type(value, struct hmap_elem);
19 } hmap SEC(".maps");
20
21 struct cls_elem {
22 struct bpf_spin_lock lock;
23 volatile int cnt;
24 };
25
26 struct {
27 __uint(type, BPF_MAP_TYPE_CGROUP_STORAGE);
28 __type(key, struct bpf_cgroup_storage_key);
29 __type(value, struct cls_elem);
30 } cls_map SEC(".maps");
31
32 struct bpf_vqueue {
33 struct bpf_spin_lock lock;
34 /* 4 byte hole */
35 unsigned long long lasttime;
36 int credit;
37 unsigned int rate;
38 };
39
40 struct {
41 __uint(type, BPF_MAP_TYPE_ARRAY);
42 __uint(max_entries, 1);
43 __type(key, int);
44 __type(value, struct bpf_vqueue);
45 } vqueue SEC(".maps");
46
47 #define CREDIT_PER_NS(delta, rate) (((delta) * rate) >> 20)
48
49 SEC("cgroup_skb/ingress")
bpf_spin_lock_test(struct __sk_buff * skb)50 int bpf_spin_lock_test(struct __sk_buff *skb)
51 {
52 volatile int credit = 0, max_credit = 100, pkt_len = 64;
53 struct hmap_elem zero = {}, *val;
54 unsigned long long curtime;
55 struct bpf_vqueue *q;
56 struct cls_elem *cls;
57 int key = 0;
58 int err = 0;
59
60 val = bpf_map_lookup_elem(&hmap, &key);
61 if (!val) {
62 bpf_map_update_elem(&hmap, &key, &zero, 0);
63 val = bpf_map_lookup_elem(&hmap, &key);
64 if (!val) {
65 err = 1;
66 goto err;
67 }
68 }
69 /* spin_lock in hash map run time test */
70 bpf_spin_lock(&val->lock);
71 if (val->cnt)
72 val->cnt--;
73 else
74 val->cnt++;
75 if (val->cnt != 0 && val->cnt != 1)
76 err = 1;
77 bpf_spin_unlock(&val->lock);
78
79 /* spin_lock in array. virtual queue demo */
80 q = bpf_map_lookup_elem(&vqueue, &key);
81 if (!q)
82 goto err;
83 curtime = bpf_ktime_get_ns();
84 bpf_spin_lock(&q->lock);
85 q->credit += CREDIT_PER_NS(curtime - q->lasttime, q->rate);
86 q->lasttime = curtime;
87 if (q->credit > max_credit)
88 q->credit = max_credit;
89 q->credit -= pkt_len;
90 credit = q->credit;
91 bpf_spin_unlock(&q->lock);
92
93 __sink(credit);
94
95 /* spin_lock in cgroup local storage */
96 cls = bpf_get_local_storage(&cls_map, 0);
97 bpf_spin_lock(&cls->lock);
98 cls->cnt++;
99 bpf_spin_unlock(&cls->lock);
100
101 err:
102 return err;
103 }
104 char _license[] SEC("license") = "GPL";
105