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bpf: Compute map_btf_id during build time

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For now, the field 'map_btf_id' in 'struct bpf_map_ops' for all map
types are computed during vmlinux-btf init:

  btf_parse_vmlinux() -> btf_vmlinux_map_ids_init()

It will lookup the btf_type according to the 'map_btf_name' field in
'struct bpf_map_ops'. This process can be done during build time,
thanks to Jiri's resolve_btfids.

selftest of map_ptr has passed:

  $96 map_ptr:OK
  Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Menglong Dong 2022-04-25 21:32:47 +08:00 • committed by Alexei Starovoitov
parent 367590b7fc
commit c317ab71fa
19 changed files with 62 additions and 129 deletions
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5
kernel/bpf/stackmap.c
View file

@ -654,7 +654,7 @@ static void stack_map_free(struct bpf_map *map)
put_callchain_buffers();
}
static int stack_trace_map_btf_id;
BTF_ID_LIST_SINGLE(stack_trace_map_btf_ids, struct, bpf_stack_map)
const struct bpf_map_ops stack_trace_map_ops = {
.map_meta_equal = bpf_map_meta_equal,
.map_alloc = stack_map_alloc,
@ -664,6 +664,5 @@ const struct bpf_map_ops stack_trace_map_ops = {
.map_update_elem = stack_map_update_elem,
.map_delete_elem = stack_map_delete_elem,
.map_check_btf = map_check_no_btf,
.map_btf_name = "bpf_stack_map",
.map_btf_id = &stack_trace_map_btf_id,
.map_btf_id = &stack_trace_map_btf_ids[0],
};