1/* SPDX-License-Identifier: GPL-2.0 */
2/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
3
4#ifndef _CGRP_KFUNC_COMMON_H
5#define _CGRP_KFUNC_COMMON_H
6
7#include <errno.h>
8#include <vmlinux.h>
9#include <bpf/bpf_helpers.h>
10#include <bpf/bpf_tracing.h>
11
12struct __cgrps_kfunc_map_value {
13 struct cgroup __kptr * cgrp;
14};
15
16struct hash_map {
17 __uint(type, BPF_MAP_TYPE_HASH);
18 __type(key, int);
19 __type(value, struct __cgrps_kfunc_map_value);
20 __uint(max_entries, 1);
21} __cgrps_kfunc_map SEC(".maps");
22
23struct cgroup *bpf_cgroup_acquire(struct cgroup *p) __ksym;
24void bpf_cgroup_release(struct cgroup *p) __ksym;
25struct cgroup *bpf_cgroup_ancestor(struct cgroup *cgrp, int level) __ksym;
26struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym;
27void bpf_rcu_read_lock(void) __ksym;
28void bpf_rcu_read_unlock(void) __ksym;
29
30static inline struct __cgrps_kfunc_map_value *cgrps_kfunc_map_value_lookup(struct cgroup *cgrp)
31{
32 s32 id;
33 long status;
34
35 status = bpf_probe_read_kernel(&id, sizeof(id), &cgrp->self.id);
36 if (status)
37 return NULL;
38
39 return bpf_map_lookup_elem(&__cgrps_kfunc_map, &id);
40}
41
42static inline int cgrps_kfunc_map_insert(struct cgroup *cgrp)
43{
44 struct __cgrps_kfunc_map_value local, *v;
45 long status;
46 struct cgroup *acquired, *old;
47 s32 id;
48
49 status = bpf_probe_read_kernel(&id, sizeof(id), &cgrp->self.id);
50 if (status)
51 return status;
52
53 local.cgrp = NULL;
54 status = bpf_map_update_elem(&__cgrps_kfunc_map, &id, &local, BPF_NOEXIST);
55 if (status)
56 return status;
57
58 v = bpf_map_lookup_elem(&__cgrps_kfunc_map, &id);
59 if (!v) {
60 bpf_map_delete_elem(&__cgrps_kfunc_map, &id);
61 return -ENOENT;
62 }
63
64 acquired = bpf_cgroup_acquire(cgrp);
65 if (!acquired) {
66 bpf_map_delete_elem(&__cgrps_kfunc_map, &id);
67 return -ENOENT;
68 }
69
70 old = bpf_kptr_xchg(&v->cgrp, acquired);
71 if (old) {
72 bpf_cgroup_release(old);
73 return -EEXIST;
74 }
75
76 return 0;
77}
78
79#endif /* _CGRP_KFUNC_COMMON_H */
80

source code of linux/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h