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 | |
12 | struct __cgrps_kfunc_map_value { |
13 | struct cgroup __kptr * cgrp; |
14 | }; |
15 | |
16 | struct 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 | |
23 | struct cgroup *bpf_cgroup_acquire(struct cgroup *p) __ksym; |
24 | void bpf_cgroup_release(struct cgroup *p) __ksym; |
25 | struct cgroup *bpf_cgroup_ancestor(struct cgroup *cgrp, int level) __ksym; |
26 | struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym; |
27 | void bpf_rcu_read_lock(void) __ksym; |
28 | void bpf_rcu_read_unlock(void) __ksym; |
29 | |
30 | static 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 | |
42 | static 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 | |