Re: [PATCH v2 2/6] sysctl: add unsigned int limit constants

[Joel Granados]

On Mon, Sep 21, 2026 at 12:54:49PM +0200, Alexey Gladkov wrote:
> Some sysctl handlers use unsigned int storage for their limit arguments.
> In particular, proc_dou8vec_minmax() expects extra1 and extra2 to point
> to unsigned int values even though the controlled data is an u8.

This one reads like a fix as opposed to part of your series. Is it
strictly needed for what you are proposing here?

> 
> Provide shared unsigned int constants so typed sysctl descriptors can
> pass correctly typed min and max pointers without casting the existing
> int constants.
> 
> Signed-off-by: Alexey Gladkov <legion@xxxxxxxxxx>
> ---
>  include/linux/sysctl.h | 7 +++++++
>  kernel/sysctl.c        | 3 +++
>  2 files changed, 10 insertions(+)
> 
> diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
> index e5d7226ab6f5..7139a4c72736 100644
> --- a/include/linux/sysctl.h
> +++ b/include/linux/sysctl.h
> @@ -59,6 +59,12 @@ extern const int sysctl_vals[];
>  #define SYSCTL_LONG_ONE		((void *)&sysctl_long_vals[1])
>  #define SYSCTL_LONG_MAX		((void *)&sysctl_long_vals[2])
>  
> +#define SYSCTL_UINT_ZERO	((unsigned int *)&sysctl_uint_vals[0])
> +#define SYSCTL_UINT_ONE		((unsigned int *)&sysctl_uint_vals[1])
> +#define SYSCTL_UINT_TWO		((unsigned int *)&sysctl_uint_vals[2])
> +#define SYSCTL_UINT_THREE	((unsigned int *)&sysctl_uint_vals[3])
> +#define SYSCTL_UINT_FOUR	((unsigned int *)&sysctl_uint_vals[4])

I would really like to avoid that. Its one of the things that should
probably go away in the future [1], [2], [3], [4]

[1] https://lore.kernel.org/all/875xyczpzm.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
[2] https://lore.kernel.org/all/tencent_C5E6023F97E7CC2A046AAEA09BC9ACF43907@xxxxxx/
[3] https://lore.kernel.org/all/cover.1739115369.git.wen.yang@xxxxxxxxx/
[4] https://lore.kernel.org/all/qnrzl4tjlgw5rzlvxavr3pt7fhkslnm4dd62q7uqzb3mfoa2jg@fuayx77rfcs6/


> +
>  /*
>   *
>   * "dir" originates from read_iter (dir = 0) or write_iter (dir = 1)
> @@ -73,6 +79,7 @@ extern const int sysctl_vals[];
>  #define SYSCTL_KERN_TO_USER(dir) (!dir)
>  
>  extern const unsigned long sysctl_long_vals[];
> +extern const unsigned int sysctl_uint_vals[];
>  
>  typedef int proc_handler(const struct ctl_table *ctl, int dir, void *buf,
>  			 size_t *lenp, loff_t *ppos);
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index f7b75985d542..54edaa2fd5d5 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -29,6 +29,9 @@ EXPORT_SYMBOL(sysctl_vals);
>  const unsigned long sysctl_long_vals[] = { 0, 1, LONG_MAX };
>  EXPORT_SYMBOL_GPL(sysctl_long_vals);
>  
> +const unsigned int sysctl_uint_vals[] = { 0, 1, 2, 3, 4 };
> +EXPORT_SYMBOL_GPL(sysctl_uint_vals);
> +
>  #if defined(CONFIG_SYSCTL)
>  
>  /* Constants used for minimum and maximum */
> -- 
> 2.55.0
>

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