Re: [PATCH RFC v2 06/13] sysctl, net: add register_net_sysctl{_sz}() wrappers for MODULE_SYSCTL_TABLE

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] When `CONFIG_SYSCTL` is disabled, the build fails due to a preprocessor conflict where the newly introduced `register_net_sysctl_sz` macro expands inside its own fallback static inline function definition.
--

--- Patch [6]: [PATCH RFC v2 06/13] sysctl, net: add register_net_sysctl{_sz}() wrappers for MODULE_SYSCTL_TABLE ---
commit fad97277609904f7e692d6e11a61fdff7e4ff635
Author: Mauricio Faria de Oliveira <mfo@igalia.com>

sysctl, net: add register_net_sysctl{_sz}() wrappers for MODULE_SYSCTL_TABLE

This commit replaces register_net_sysctl() and register_net_sysctl_sz() with
macros that automatically use MODULE_SYSCTL_TABLE for existing callers. It
renames the actual sysctl registration function to __register_net_sysctl_sz()
and adds optional template arguments to support dynamically defined paths and
tables.

> diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
> index e5ee673b9fcf8..2127049c71ced 100644
> --- a/include/net/net_namespace.h
> +++ b/include/net/net_namespace.h
[ ... ]
> @@ -520,13 +520,48 @@ void unregister_pernet_device(struct pernet_operations *);
>  
>  struct ctl_table;
>  
> -#define register_net_sysctl(net, path, table)	\
> -	register_net_sysctl_sz(net, path, table, ARRAY_SIZE(table))
> +/*
> + * The register_net_sysctl{_sz}() wrappers for MODULE_SYSCTL_TABLE
> + * automatically create symbols in sysctl registration sites.
[ ... ]
> + */
> +#define _register_net_sysctl_sz(net, path, table, size, table_tmpl, path_tmpl)	\
> +({										\
> +	MODULE_SYSCTL_TABLE(path_tmpl, table_tmpl);				\
> +	__register_net_sysctl_sz(net, path, table, size);			\
> +})
> +
> +#define register_net_sysctl_sz(net, path, table, size, tmpl_args...)		\
> +	_register_net_sysctl_sz(net, path, table, size,				\
> +				__sysctl_table_tmpl_or_default(table,		\
> +							       ## tmpl_args),	\
> +				__sysctl_path_tmpl_or_default(path,		\
> +							      ## tmpl_args))
> +#define register_net_sysctl(net, path, table, tmpl_args...)			\
> +	register_net_sysctl_sz(net, path, table,				\
> +			       __sysctl_table_array_size(table, ## tmpl_args),	\
> +			       ## tmpl_args)
> +
> +/* Helper macro for optional template arguments */
> +#define __sysctl_table_array_size(table, tmpl_args...)	\
> +	ARRAY_SIZE(__sysctl_table_tmpl_or_default(table, ## tmpl_args))
> +
>  #ifdef CONFIG_SYSCTL
>  int net_sysctl_init(void);
> -struct ctl_table_header *register_net_sysctl_sz(struct net *net, const char *path,
> -						const struct ctl_table *table,
> -						size_t table_size);
> +struct ctl_table_header *__register_net_sysctl_sz(struct net *net,
> +						  const char *path,
> +						  const struct ctl_table *table,
> +						  size_t table_size);
>  void unregister_net_sysctl_table(struct ctl_table_header *header);
>  #else
>  static inline int net_sysctl_init(void) { return 0; }

[Severity: Low]
Does this commit break the build when CONFIG_SYSCTL is disabled?

Because register_net_sysctl_sz() is now defined as a macro unconditionally
above, the fallback static inline function in this #else block:

static inline struct ctl_table_header *register_net_sysctl_sz(struct net *net,
	const char *path, const struct ctl_table *table, size_t table_size)
{
	return NULL;
}

will cause a macro expansion conflict.

Should this static inline function be renamed to __register_net_sysctl_sz()
to avoid expanding the macro in its own definition and to provide the fallback
implementation needed by the new macro?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260818-sysctl-module-aliases-v2-0-d5a69dae5798@igalia.com?part=6