From: Martin KaFai Lau <martin.lau@linux.dev>
To: Kui-Feng Lee <sinquersw@gmail.com>
Cc: kuifeng@meta.com, netdev@vger.kernel.org, bpf@vger.kernel.org,
ast@kernel.org, song@kernel.org, kernel-team@meta.com,
andrii@kernel.org, thinker.li@gmail.com, drosen@google.com
Subject: Re: [PATCH bpf-next v8 07/10] bpf, net: switch to dynamic registration
Date: Tue, 31 Oct 2023 17:02:56 -0700 [thread overview]
Message-ID: <5a8520dd-0dd6-4d51-9e4a-6eebcf7e792d@linux.dev> (raw)
In-Reply-To: <10f383a2-c83b-4a40-a1f9-bcf33c76c164@gmail.com>
On 10/31/23 4:34 PM, Kui-Feng Lee wrote:
>>> diff --git a/include/linux/btf.h b/include/linux/btf.h
>>> index a8813605f2f6..954536431e0b 100644
>>> --- a/include/linux/btf.h
>>> +++ b/include/linux/btf.h
>>> @@ -12,6 +12,8 @@
>>> #include <uapi/linux/bpf.h>
>>> #define BTF_TYPE_EMIT(type) ((void)(type *)0)
>>> +#define BTF_STRUCT_OPS_TYPE_EMIT(type) {((void)(struct type *)0); \
>>
>> ((void)(struct type *)0); is new. Why is it needed?
>
> This is a trick of BTF to force compiler generate type info for
> the given type. Without trick, compiler may skip these types if these
> type are not used at all in the module. For example, modules usually
> don't use value types of struct_ops directly.
It is not the value type and value type emit is understood. It is the struct_ops
type itself and it is new addition in this patchset afaict. The value type emit
is in the next line which was cut out from the context here.
next prev parent reply other threads:[~2023-11-01 0:03 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-30 19:28 [PATCH bpf-next v8 00/10] Registrating struct_ops types from modules thinker.li
2023-10-30 19:28 ` [PATCH bpf-next v8 01/10] bpf: refactory struct_ops type initialization to a function thinker.li
2023-10-30 19:28 ` [PATCH bpf-next v8 02/10] bpf, net: introduce bpf_struct_ops_desc thinker.li
2023-10-31 6:40 ` Martin KaFai Lau
2023-10-31 16:00 ` Kui-Feng Lee
2023-10-30 19:28 ` [PATCH bpf-next v8 03/10] bpf: add struct_ops_tab to btf thinker.li
2023-10-31 1:09 ` Martin KaFai Lau
2023-10-31 16:57 ` Kui-Feng Lee
2023-10-30 19:28 ` [PATCH bpf-next v8 04/10] bpf: hold module for bpf_struct_ops_map thinker.li
2023-10-31 1:21 ` Martin KaFai Lau
2023-10-31 17:46 ` Kui-Feng Lee
2023-10-30 19:28 ` [PATCH bpf-next v8 05/10] bpf: validate value_type thinker.li
2023-10-30 19:28 ` [PATCH bpf-next v8 06/10] bpf: pass attached BTF to the bpf_struct_ops subsystem thinker.li
2023-10-31 1:53 ` Martin KaFai Lau
2023-10-31 20:31 ` Kui-Feng Lee
2023-10-30 19:28 ` [PATCH bpf-next v8 07/10] bpf, net: switch to dynamic registration thinker.li
2023-10-31 6:36 ` Martin KaFai Lau
2023-10-31 23:34 ` Kui-Feng Lee
2023-11-01 0:02 ` Martin KaFai Lau [this message]
2023-11-01 0:19 ` Kui-Feng Lee
2023-11-01 0:19 ` Kui-Feng Lee
2023-11-02 0:17 ` Martin KaFai Lau
2023-11-02 0:59 ` Kui-Feng Lee
2023-11-02 1:32 ` Martin KaFai Lau
2023-11-02 4:19 ` Kui-Feng Lee
2023-10-30 19:28 ` [PATCH bpf-next v8 08/10] libbpf: Find correct module BTFs for struct_ops maps and progs thinker.li
2023-10-30 19:28 ` [PATCH bpf-next v8 09/10] bpf: export btf_ctx_access to modules thinker.li
2023-10-30 19:28 ` [PATCH bpf-next v8 10/10] selftests/bpf: test case for register_bpf_struct_ops() thinker.li
2023-10-31 6:59 ` Martin KaFai Lau
2023-11-01 0:30 ` Kui-Feng Lee
2023-11-02 1:43 ` Martin KaFai Lau
2023-11-02 18:26 ` Kui-Feng Lee
2023-10-31 20:45 ` [PATCH bpf-next v8 00/10] Registrating struct_ops types from modules Martin KaFai Lau
2023-11-01 0:48 ` Kui-Feng Lee
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