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
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[];
-- 
2.34.1

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

On Fri, Apr 26, 2024 at 8:54 AM Daniel Borkmann <daniel@iogearbox.net> wrote:
>
> 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'.
>

Adjusted commit message and pushed to bpf-next, thanks.

> Thanks,
> Daniel