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author | Andrii Nakryiko <andrii@kernel.org> | 2022-01-19 22:05:29 -0800 |
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committer | Alexei Starovoitov <ast@kernel.org> | 2022-01-20 21:19:05 -0800 |
commit | 96c85308eed9a31a53a0f4f2bd6a85bb88776e93 (patch) | |
tree | 7f71ccb566383db2b21700a76f30867954b76ed9 /Documentation/bpf | |
parent | 93b8952d223af03c51fba0c6258173d2ffbd2cb7 (diff) | |
download | linux-96c85308eed9a31a53a0f4f2bd6a85bb88776e93.tar.bz2 |
docs/bpf: update BPF map definition example
Use BTF-defined map definition in the documentation example.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220120060529.1890907-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'Documentation/bpf')
-rw-r--r-- | Documentation/bpf/btf.rst | 32 |
1 files changed, 14 insertions, 18 deletions
diff --git a/Documentation/bpf/btf.rst b/Documentation/bpf/btf.rst index 1ebf4c5c7ddc..ab08852e53ae 100644 --- a/Documentation/bpf/btf.rst +++ b/Documentation/bpf/btf.rst @@ -565,18 +565,15 @@ A map can be created with ``btf_fd`` and specified key/value type id.:: In libbpf, the map can be defined with extra annotation like below: :: - struct bpf_map_def SEC("maps") btf_map = { - .type = BPF_MAP_TYPE_ARRAY, - .key_size = sizeof(int), - .value_size = sizeof(struct ipv_counts), - .max_entries = 4, - }; - BPF_ANNOTATE_KV_PAIR(btf_map, int, struct ipv_counts); + struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, struct ipv_counts); + __uint(max_entries, 4); + } btf_map SEC(".maps"); -Here, the parameters for macro BPF_ANNOTATE_KV_PAIR are map name, key and -value types for the map. During ELF parsing, libbpf is able to extract -key/value type_id's and assign them to BPF_MAP_CREATE attributes -automatically. +During ELF parsing, libbpf is able to extract key/value type_id's and assign +them to BPF_MAP_CREATE attributes automatically. .. _BPF_Prog_Load: @@ -824,13 +821,12 @@ structure has bitfields. For example, for the following map,:: ___A b1:4; enum A b2:4; }; - struct bpf_map_def SEC("maps") tmpmap = { - .type = BPF_MAP_TYPE_ARRAY, - .key_size = sizeof(__u32), - .value_size = sizeof(struct tmp_t), - .max_entries = 1, - }; - BPF_ANNOTATE_KV_PAIR(tmpmap, int, struct tmp_t); + struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, struct tmp_t); + __uint(max_entries, 1); + } tmpmap SEC(".maps"); bpftool is able to pretty print like below: :: |