On Tue, May 13, 2025 at 09:07:32AM -0400, Kent Overstreet wrote:
> Static keys can now be a module parameter, e.g.
>
> module_param_named(foo, foo.key, static_key_t, 0644)
>
> bcachefs is now using this.
>
> Cc: Luis Chamberlain <mcg...@kernel.org>
> Cc: Petr Pavlu <petr.pa...@suse.com>
> Cc: Sami Tolvanen <samitolva...@google.com>
> Cc: Daniel Gomez <da.go...@samsung.com>
> Cc: linux-modu...@vger.kernel.org
> Cc: Peter Zijlstra <pet...@infradead.org>
> Cc: Josh Poimboeuf <jpoim...@kernel.org>
> Cc: Jason Baron <jba...@akamai.com>
> Cc: Steven Rostedt <rost...@goodmis.org>
> Cc: Ard Biesheuvel <a...@kernel.org>
> Signed-off-by: Kent Overstreet <kent.overstr...@linux.dev>
> ---
> include/linux/jump_label.h | 2 ++
> include/linux/moduleparam.h | 7 +++++++
> kernel/params.c | 35 +++++++++++++++++++++++++++++++++++
> 3 files changed, 44 insertions(+)
>
> diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
> index fdb79dd1ebd8..0fc9b71db56f 100644
> --- a/include/linux/jump_label.h
> +++ b/include/linux/jump_label.h
> @@ -107,6 +107,8 @@ struct static_key {
> #endif /* CONFIG_JUMP_LABEL */
> };
>
> +typedef struct static_key static_key_t;
> +
> #endif /* __ASSEMBLY__ */
>
> #ifdef CONFIG_JUMP_LABEL
> diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
> index bfb85fd13e1f..11e8d5c57435 100644
> --- a/include/linux/moduleparam.h
> +++ b/include/linux/moduleparam.h
> @@ -122,6 +122,7 @@ struct kparam_array
> * charp: a character pointer
> * bool: a bool, values 0/1, y/n, Y/N.
> * invbool: the above, only sense-reversed (N = true).
> + * static_key_t: same as bool, but updates a 'struct static_key'
The static_key_*() interfaces are deprecated because they're really easy
to use incorrectly. I don't think we want to propagate that misuse to
modules.
It would be better to have type(s) based on static_key_false and/or
static_key_true, depending on whatever the default is.
--
Josh
