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From:   Jiri Olsa <olsajiri@gmail.com>
Date:   Tue, 17 Oct 2023 18:13:24 +0200
To:     Arnd Bergmann <arnd@kernel.org>
Cc:     Yury Norov <yury.norov@gmail.com>,
        Song Liu <songliubraving@fb.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] buildid: reduce header file dependencies for module
Message-ID: <ZS6ypB/Jb+rOXqVK@krava>
References: <20231017143408.2876181-1-arnd@kernel.org>
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On Tue, Oct 17, 2023 at 04:33:58PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> The vmlinux decompressor code intentionally has only a limited set of
> included header files, but this started running into a build failure
> because of the bitmap logic needing linux/errno.h:
> 
> In file included from include/linux/cpumask.h:12,
>                  from include/linux/mm_types_task.h:14,
>                  from include/linux/mm_types.h:5,
>                  from include/linux/buildid.h:5,
>                  from include/linux/module.h:14,
>                  from arch/arm/boot/compressed/../../../../lib/lz4/lz4_decompress.c:39,
>                  from arch/arm/boot/compressed/../../../../lib/decompress_unlz4.c:10,
>                  from arch/arm/boot/compressed/decompress.c:60:
> include/linux/bitmap.h: In function 'bitmap_allocate_region':
> include/linux/bitmap.h:527:25: error: 'EBUSY' undeclared (first use in this function)
>   527 |                 return -EBUSY;
>       |                         ^~~~~
> include/linux/bitmap.h:527:25: note: each undeclared identifier is reported only once for each function it appears in
> include/linux/bitmap.h: In function 'bitmap_find_free_region':
> include/linux/bitmap.h:554:17: error: 'ENOMEM' undeclared (first use in this function)
>   554 |         return -ENOMEM;
>       |                 ^~~~~~
> 
> This is easily avoided by changing linux/buildid.h to no longer depend on
> linux/mm_types.h, a header that pulls in a huge number of indirect dependencies.
> 
> Fixes: b9c957f554442 ("bitmap: move bitmap_*_region() functions to bitmap.h")
> Fixes: bd7525dacd7e2 ("bpf: Move stack_map_get_build_id into lib")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  include/linux/buildid.h | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/buildid.h b/include/linux/buildid.h
> index 3b7a0ff4642fd..8a582d242f067 100644
> --- a/include/linux/buildid.h
> +++ b/include/linux/buildid.h
> @@ -2,10 +2,11 @@
>  #ifndef _LINUX_BUILDID_H
>  #define _LINUX_BUILDID_H
>  
> -#include <linux/mm_types.h>
> +#include <linux/types.h>

looks good, but I think we should now include <linux/mm_types.h> in lib/buildid.c ?

thanks,
jirka

>  
>  #define BUILD_ID_SIZE_MAX 20
>  
> +struct vm_area_struct;
>  int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id,
>  		   __u32 *size);
>  int build_id_parse_buf(const void *buf, unsigned char *build_id, u32 buf_size);
> -- 
> 2.39.2
>