Subject: Re: [PATCH iproute2] Fix compilation with kernel headers < 3.4

From: Stephen Hemminger <[email-masked]>
Date: Mon, 26 Feb 2018 10:58:10 -0800

On Mon, 26 Feb 2018 19:51:12 +0100
Thomas De Schampheleire <[email-masked]> wrote:

> Since commit 596b1c94aa38e21b7a8c8562e8b61ccb744255d2, iproute2 uses types
> __kernel_long_t and __kernel_ulong_t but does not provide internal
> definitions for it.
> 
> This means that compilation using kernel headers that are older than 3.4
> (where these types were added) will fail. This situation may be uncommon for
> native compilation, but not uncommon for cross compilation where the
> toolchains may be a bit older.
> 
> Provide the necessary types internally if not provided by the kernel
> headers to fix compilation in such cases.
> 
> Signed-off-by: Thomas De Schampheleire <[email-masked]>
> ---
>  include/uapi/linux/posix_types.h | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/include/uapi/linux/posix_types.h b/include/uapi/linux/posix_types.h
> index 9a7a740b..60f3d378 100644
> --- a/include/uapi/linux/posix_types.h
> +++ b/include/uapi/linux/posix_types.h
> @@ -35,4 +35,13 @@ typedef int __kernel_mqd_t;
>  
>  #include <asm/posix_types.h>
>  
> +/* in case the kernel header asm/posix_types.h is too old (< 3.4) to provide
> + * __kernel_long_t, provide it here */
> +#ifndef __kernel_long_t
> +typedef long		__kernel_long_t;
> +#endif
> +#ifndef __kernel_ulong_t
> +typedef unsigned long	__kernel_ulong_t;
> +#endif
> +
>  #endif /* _LINUX_POSIX_TYPES_H */

No.

The headers in uapi are automatically generated from the upstream kernel
headers. If there are places that need to have backwards compatibility,
fix it in the main iproute2 source.