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