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Subject: Re: [PATCH bpf-next v3] bpf: btf: include linux/types.h for u32
To: Dmitrii Bundin <dmitrii.bundin.a@gmail.com>, olsajiri@gmail.com
Cc: andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org, dxu@dxuuu.xyz,
 eddyz87@gmail.com, haoluo@google.com, john.fastabend@gmail.com,
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 martin.lau@linux.dev, ncopa@alpinelinux.org, ndesaulniers@google.com,
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References: <Zh93hKfHgsw5wQAw@krava>
 <20240420042457.3198883-1-dmitrii.bundin.a@gmail.com>
From: Daniel Borkmann <daniel@iogearbox.net>
Message-ID: <9ca4b5dd-20be-79ac-52eb-a19c0c82280f@iogearbox.net>
Date: Fri, 26 Apr 2024 17:54:28 +0200
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On 4/20/24 6:24 AM, Dmitrii Bundin wrote:
> Inclusion of the header linux/btf_ids.h relies on indirect inclusion of
> the header linux/types.h. Including it directly on the top level helps
> to avoid potential problems if linux/types.h hasn't been included
> before.
> 
> The main motiviation to introduce this it is to avoid similar problems that

nit: spelling

> was shown up in the bpf tool where GNU libc indirectly pulls
> linux/types.h causing compile error of the form:
> 
>     error: unknown type name 'u32'
>                               u32 cnt;
>                               ^~~
> 
> The bpf tool compile error was fixed at 62248b22d01e96a4d669cde0d7005bd51ebf9e76
> 
> Fixes: 9707ac4fe2f5 ("tools/resolve_btfids: Refactor set sorting with types from btf_ids.h")
> 
> Signed-off-by: Dmitrii Bundin <dmitrii.bundin.a@gmail.com>
> ---
> 
> Changes in v2: Add bpf-next to the subject
> Changes in v3: Add Fixes tag and bpf tool commit reference
> 
>   include/linux/btf_ids.h | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
> index e24aabfe8ecc..c0e3e1426a82 100644
> --- a/include/linux/btf_ids.h
> +++ b/include/linux/btf_ids.h
> @@ -3,6 +3,8 @@
>   #ifndef _LINUX_BTF_IDS_H
>   #define _LINUX_BTF_IDS_H
>   
> +#include <linux/types.h> /* for u32 */
> +
>   struct btf_id_set {
>   	u32 cnt;
>   	u32 ids[];
> 

Lgtm, not sure if its worth it but also doesn't hurt and aligns the header
from tooling a bit closer to the kernel one. Just to clarify, this does not
fix a concrete issue today, so small 'cleanup' rather than 'fix'.

Thanks,
Daniel