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authorAndrii Nakryiko <andrii@kernel.org>2022-01-20 09:05:29 +0300
committerAlexei Starovoitov <ast@kernel.org>2022-01-21 08:19:05 +0300
commit96c85308eed9a31a53a0f4f2bd6a85bb88776e93 (patch)
tree7f71ccb566383db2b21700a76f30867954b76ed9 /Documentation/bpf
parent93b8952d223af03c51fba0c6258173d2ffbd2cb7 (diff)
downloadlinux-96c85308eed9a31a53a0f4f2bd6a85bb88776e93.tar.xz
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.rst32
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:
::